| Title of Invention | “PROCESS FOR PRODUCING PROPYLENE” |
|---|---|
| Abstract | DISCLOSED IS A NOVEL PROCESS FOR PRODUCING PROPYLENE BY USING ETHYLENE AND AT LEAST ONE MEMBER SELECTED FROM METHANOL AND DIMETHYL ETHER AS STARTING MATERIALS, WHICH CAN REDUCE THE AMOUNT OF UNREACTED ETHYLENE TO BE RECYCLED AND HAS LOW EQUIPMENT COST AND RUNNING COST. SPECIFICALLY DISCLOSED IS A PROCESS FOR PRODUCING PROPYLENE BY USING ETHYLENE AND AT LEAST ONE MEMBER SELECTED FROM METHANOL AND DIMETHYL ETHER AS STARTING MATERIALS, WHICH COMPRISES REACTING ETHYLENE AND AT LEAST ONE MEMBER SELECTED FROM METHANOL AND DIMETHYL ETHER UNDER SPECIFIC CONDITIONS TO PRODUCE A FLUID CONTAINING AN OLEFIN HAVING 4 OR MORE CARBON ATOMS, AND THEN REACTING AT LEAST A PART OF THE OLEFIN HAVING 4 OR MORE CARBON ATOMS CONTAINED IN THE FLUID WITH AT LEAST ONE MEMBER SELECTED FROM METHANOL AND DIMETHYL ETHER UNDER SPECIFIC CONDITIONS, THEREBY PRODUCING PROPYLENE. |
| Full Text | DESCRIPTION PROCESS FOR PRODUCING PROPYLENE [Technical Field] The present invention relates to a process for producing propylene with the use of ethylene and at least one of methanol and dimethyl ether as raw material. [Background Art] Conventionally, steam cracking using naphtha or ethane and fluid catalytic cracking of vacuum gas oil have been generally carried out for producing propylene. Further, metathesis using ethylene and 2-butene as a raw material, catalytic cracking of olefin of 4 or more carbon atoms, and the methanol to olefin (MTO) process using at least one of methanol and dimethyl ether as a raw material are currently noticeable as a process for producing propylene. In addition, it is known to produce propylene involving olefin and at least one of methanol and dimethyl ether. A process which uses olefin of 4 or more carbon atoms as a raw material and a process which uses ethylene are disclosed in the following patent documents 1 and 2, respectively. [Patent Document 1] U.S. Patent Application No. 6,888,038 [Patent Document 2] W02005/056504 Meanwhile, as a process of producing butane, a process to dimerize ethylene is disclosed {Non-patent documents 1 and 2) . [Non-patent Document 1] Catalysis Today, 14, (1992) 28 [Non-patent Document 2] Journal of the Chemical Society of Japan. Industrial chemistry Vol.66, Issue 7 (1963) 973 [Disclosure of the Invention] [Problem that the Invention is to solve] Among a variety of processes for producing propylene, a process involving steam cracking is widely used in the world, but it has limitations in changing yield balance of ethylene and propylene depending on changes on balance of their supply and demand. In the case that a ratio of demand for propylene to demand for ethylene is increased, a process for producing propylene using ethylene as a feed is effective. For example, the re is a method to produce propylene involving a reaction of ethylene and at least one of methanol and dimethyl ether. However, in the results of studying from the reaction of ethylene and at least one of methanol and dimethyl ether, it is recognized that the production of olefin of 4 or more carbon atoms is large under the reaction conditions where the conversion ratio of ethylene is improved so that a high selectivity of propylene may not be obtained. Meanwhile, it is also recognized that the conversion ratio of ethylene is low under the reaction conditions where propylene is high- selectively obtained, and thus a weight ratio of ethylene to propylene becomes considerably high in an outlet of a reactor (generally, the weight ratio of ethylene/propylene is 2.0 or more). In this case, it is necessary to recycle a great amount of unreacted ethylene in the reactor, and accordingly, there is a problem that the cost for equipment and service becomes a great deal. Accordingly, the present invention is to provide a novel process for producing propylene using ethylene and at least one of methanol and dimethyl ether as raw material in which the amount of unreacted ethylene to be recycled is small and the cost for equipment and service is low. [Means for Solving the Problem] With a result that the inventors of the present invention examine a process to reduce the recycling amount of ethylene, it is found that ethylene and at least one of methanol and dimethyl ether are reacted with each other under specific reaction conditions to obtain a fluid containing propylene and olefin of 4 or more carbon atoms, and at least part of the olefin of 4 or more carbon atoms contained in the fluid is reacted with at least one of methanol and dimethyl ether to thereby reduce the recycling amount of ethylene and to produce propylene in high selectivity. Further, as a result of inventors' examination on a process for producing propylene by reacting olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether, it is found that, instead of directly reacting ethylene with at least one of methanol and dimethyl ether, in the case that ethylene is converted into hydrocarbon of 4 or more carbon atoms and at least one of methanol and dimethyl ether is reacted with the hydrocarbon of 4 or more carbon atoms, the conversion ratio of the raw materials into olefin is improved as compared with in the case ethylene and at least one of methanol and dimethyl ether are reacted with each other. Here, ethylene is also generated as a by-product along with propylene, and a weight ratio of ethylene/propylene in an outlet of a reactor is greatly less than 2.0. Thus, it is found that the recycling amount of ethylene to the reactor is remarkably decreased, thereby reducing the cost for equipment and service. As a result of studying a method of reducing a recycled amount of ethylene, it is found that propylene can be produced in a high selectivity as well as a reduction of recycled amount of ethylene by a process for producing propylene which comprises reacting ethylene and at least one of methanol and dimethyl ether under a specific condition to obtain a fluid containing propylene and olefin of 4 or more carbon atoms; and then reacting at least part of olefin of 4 or more carbon atoms contained in the fluid (A) and at least one of methanol and dimethyl ether, The present invention is achieved on the basis of these findings, and summarized as followings. [1] A process for producing propylene using ethylene, or ethylene and at least one of methanol and dimethyl ether as a raw material, wherein the raw material is reacted in the presence of a first catalyst in a first reactor to obtain a fluid (X) including olefin of 4 or more carbon atoms, and at least part of the fluid (X) is reacted with at least one of methanol and dimethyl ether in the presence of a second catalyst in a second reactor to obtain a fluid which includes propylene. [2] A process for producing propylene using ethylene and at least one of methanol and dimethyl ether as a raw material, wherein the ethylene and at least one of methanol and dimethyl ether are reacted in the presence of a first catalyst in a first reactor to obtain a fluid (A) which includes propylene and olefin of 4 or more carbon atoms, and at least part of olefin of 4 or more carbon atoms contained in the fluid (A) is reacted with at least one of methanol and dimethyl ether in the presence of a second catalyst in a second reactor to obtain propylene. [3] The process for producing propylene according to [2], comprising the following steps (1A), (2A), (3A), (4A), and (5A): step(lA): feeding an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (F) recycled from a step (4A) to a first reactor; and contacting the raw materials with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water, step (2A): feeding at least one of methanol and dimethyl ether as a raw material and a fluid (G) recycled from a step (5A) to a second reactor; and contacting the raw materials with a second catalyst, thereby obtaining a fluid (B) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water, step (3A): separating a fluid (C) where the fluid (A) and the fluid (B) are mixed into a hydrocarbon of 2 or less carbon atom-rich fluid (D) , a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (E), and a water-rich fluid, step (4A): recycling a part fluid (F) of the fluid (D) to the first reactor and removing the remaining fluid from the process, and step (5A): recycling a part fluid (G) of the fluid (E) to the second reactor and removing the remaining fluid from the process. [4] The process for producing propylene according to [3]^ wherein the amount of ethylene contained in the fluid (C) is less than 2.0 in a weight ratio, with respect to the amount of propylene contained in the fluid (C). [5] The process for producing propylene according to [2], comprising the following steps (IB), (2B), (3B), (4B), and {5B): step(lB): feeding an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (L) recycled from a step (4B) to a first reactor; and contacting the raw materials with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water, step (2B): feeding the fluid (A), at least one of methanol and dimethyl ether as a raw material, and a fluid (M) recycled from a step (5B) to a second reactor; and contacting the raw materials with a second catalyst, thereby obtaining a fluid (I) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water, step (3B): separating the fluid (I) into a hydrocarbon of 2 or less carbon atom-rich fluid (J), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (K), and a water-rich fluid, step (4B): recycling a part fluid (L) of the fluid (J) to the first reactor and removing the remaining fluid from the process, and step (5B): recycling a part fluid (M) of the fluid (K) to the second reactor and removing the remaining fluid from the process. [6] The process for producing propylene according to [5], wherein the amount of ethylene contained in the fluid (I) is less than 2.0 in a weight ratio, with respect to the amount of propylene contained in the fluid (I). [7] The process for producing propylene according to any one of [1] to [6], Wherein a fluid which contains olefin of 4 or more carbon atoms is fed into the second reactor out of the process. [8] The process for producing propylene according to any one of [1] to [7], wherein an outlet of the first reactor is lower in temperature than an outlet of the second reactor. [9] The process for producing propylene according to any one of [1] to [8], wherein the conversion ratio of ethylene in the first reactor which is calculated by the following equation is 30% or more: Conversion ratio of ethylene (%) = {(flow rate of ethylene in inlet of first reactor - flow rate of ethylene in outlet of first reactor)/ flow rate of ethylene in inlet of first reactor} x 100. [10] A process for producing propylene using ethylene and at least one of methanol and dimethyl ether as a raw material, comprising a step of reacting at least one of methanol and dimethyl ether and hydrocarbon of 4 carbon atoms obtained by a dimerization reaction of ethylene. [11] The process for producing propylene according to [10], comprising the following steps (1C), (2C), (3C), (4C), and (5C): step(lC): feeding an ethylene as a raw material, and a fluid (P) recycled from a step (4C) to a first reactor; and contacting the raw materials with an ethylene dimerization catalyst, thereby obtaining a fluid (Q) which contains hydrocarbon of 4 carbon atoms, step (2C): feeding the fluid (Q) from the step (1C), a fluid (R) recycled from a step (5C), and at least one of methanol and dimethyl ether to a second reactor; and contacting the materials with a propylene production catalyst, thereby obtaining a fluid (S) which contains propylene, ethylene, the other olefin, paraffin, aromatic compound, and water, step (3C): separating the fluid (S) from the step (2C) into a hydrocarbon of 2 or less carbon atom-rich fluid (T), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (U), and a water-rich fluid, step (4C): recycling a part fluid (P) of the fluid (T) from the step (3C) to the first reactor and removing the remaining fluid from the process, and step (5C): recycling a part fluid (R) of the fluid (U) from the step (3C) to the second reactor and removing the remaining fluid from the process. [12] The process for producing propylene according to [11], wherein a part of the fluid (Q) is not fed into the second reactor in the step (2C) but removed outside the process. [13] The process for producing propylene according to [11] or [12], wherein a fluid which contains olefin of 4 or more carbon atoms is fed into the second reactor out of the process. [14] The process for producing propylene according to any one of [10] to [13], wherein the amount of ethylene contained in the fluid (S) is less than 2.0 in a weight ratio, with respect to the amount of propylene contained in the fluid (S). [Advantage of the Invention] According to the present invention, it is provided that a process for producing propylene using ethylene and at least one of methanol and dimethyl ether as raw materia in which the recycling amount of ethylene is reduced and the cost for equipment and service is not high. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a schematic diagram showing one example of an embodiment of a process for producing propylene according to the present invention. [Fig. 2] Fig. 2 is a schematic diagram showing another example of an embodiment of a process for producing propylene according to the present invention. [Fig. 3] Fig. 3 is a schematic diagram showing another example of an embodiment of a process for producing propylene according to the present invention. [Fig. 4] Fig. 4 is a schematic diagram showing a process for producing propylene of Comparative Example. [Description of Reference Numerals and Signs] 10: FIRST REACTOR 20: SECOND REACTOR 30: SEPARATION AND PURIFICATION SYSTEM 13: FIRST REACTOR 23: SECOND REACTOR 33: SEPARATION AND PURIFICATION SYSTEM [Best Mode for Carrying Out the Invention] Hereinbelow, representative embodiments to carry out the invention will be described in detail, but the invention is not limited by the following embodiments as long as it is within the scope of the invention. A process for producing propylene in accordance with the present invention is characterized by a process for producing propylene using ethylene, or ethylene and at least one of methanol and dimethyl ether as raw material, wherein the raw materials are reacted in the presence of a first catalyst in a first reactor to obtain a fluid (X) including olefin of 4 or more carbon atoms, and at least part of the fluid (X) is reacted with at least one of methanol and dimethyl ether in the presence of a second catalyst in a second reactor to obtain a fluid which includes propylene. In detail, the present invention will be illustrated with reference to a first to third embodiments in the following. A process for producing propylene in according with the present invention is characterized by a process for producing propylene using ethylene and at least one of methanol and dimethyl ether as raw material, wherein the ethylene and at least one of methanol' and dimethyl ether are reacted in the presence of a first catalyst in a first reactor to obtain a fluid (A) which includes propylene and olefin of 4 or more carbon atoms, and at least part of olefin of 4 or more carbon atoms contained in the fluid (A) is contacted with at least one of methanol and dimethyl ether in the presence of a second catalyst in a second reactor to obtain propylene. Exemplarily, the present invention comprises a process (hereinafter, referred to as a first embodiment) which includes the following steps (1A), (2A), (3A), (4A), and (5A), or a process (hereinafter, referred to as a second embodiment) which includes the following steps (IB), (2B), (3B), (4B), and First embodiment Step(lA): a step of feeding an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (F) recycled from a step (4A) to a first reactor; and contacting the raw materials with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water, Step (2A): a step of feeding at least one of methanol and dimethyl ether as a raw material and a fluid (G) recycled from a step (5A) to a second reactor; and contacting the raw materials with a second catalyst, thereby obtaining a fluid (B) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water, Step (3A): a step of separating a fluid (C) where the fluid (A) and the fluid (B) are mixed into a hydrocarbon of 2 or less carbon atom-rich fluid (D), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (E), and a water-rich fluid, Step (4A): a step of recycling a part fluid (F) of the fluid (D) to the first reactor and removing the remaining fluid from the process, and Step (5A): a step of recycling part fluid (G) of the fluid (E) to the second reactor and removing the remaining fluid from the process. Second embodiment Step(IB): a step of feeding .an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (L) recycled from a step (4B) to a first reactor; and contacting the raw materials with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water, Step (2B) : a step of feeding the fluid (A), at least one of methanol and dimethyl ether as a raw material, and a fluid (M) recycled from a step (5B) to a second reactor; and contacting the raw materials with a second catalyst, thereby obtaining a fluid (I) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water, Step (3B): a step of separating the fluid (I) into a hydrocarbon of 2 or less carbon atom-rich fluid (J), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (K), and a water-rich fluid, Step (4B): a step of recycling a part fluid (L) of the fluid (J) to the first reactor and removing the remaining fluid from the process, and Step (5B): a step of recycling a part fluid (M) of the fluid (K) to the second reactor and removing the remaining fluid from the process. According to the present invention, the term "rich" implies that a purity of the target product is 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more in the degree of purity of a target material. For example, the ^hydrocarbon of 4 or more carbon atoms-rich fluid (E)" refers to a fluid which contains "hydrocarbon of 4 or more carbon atoms" in an amount of 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more. Herein, the term "removed from the present process" means that a recycling into each of the first and second reactors in the present process is not taking place. As described above, the present invention preferably includes the steps (1A), (2A), In a third embodiment, a process for producing propylene using ethylene and at least one of methanol and dimethyl ether as raw material includes a process of reacting at least one of methanol and dimethyl ether and hydrocarbon of 4 carbon atoms obtained by a dimerization reaction of ethylene, but preferably comprises the five steps of (1), (2), (3), (4), and (5): Step(l): feeding an ethylene as a raw material, and a fluid (A) recycled from a step (4) to a first reactor; and contacting the raw materials with an ethylene dimerization catalyst, thereby obtaining a fluid (B) which contains hydrocarbon of 4 carbon atoms, Step (2): feeding the fluid (B) from the step (1), a fluid (C) recycled from a step (5), and at least one of methanol and dimethyl ether to a second reactor; and contacting the materials with a propylene production catalyst, thereby obtaining a fluid (D) which contains propylene, ethylene, the other olefin, paraffin, aromatic compound, and water, Step (3): separating the fluid (D) from the step (2) into a hydrocarbon of 2 or less carbon atom-rich fluid (E), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (F), and a water-rich fluid, Step (4): recycling a part fluid (A) of the fluid (E) from the step (3) to the first reactor and removing the remaining fluid from the process, and Step (5): recycling a part fluid (C) of the fluid (F) from the step (3) to the second reactor and removing the remaining fluid from the process. According to the present invention, the term "rich" implies that a purity of the target product is 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more in the degree of purity of a target material. For example, the "hydrocarbon of 4 or more carbon atoms-rich fluid (F)" refers to a fluid which contains "hydrocarbon of 4 or more carbon atoms" in an amount of 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% of more. Herein, the term "removed from the present process" means that a recycling into each of the first and second reactors in the present process is not taking place. As described above, the present invention preferably includes the steps (1), (2), (3), (4), and (5) but does not exclude the other processes, and another process may be included, as far as following a purpose to solve the problems of the present invention. For example, additional steps may precede or follow the five steps, or be interposed between the steps. Hereinafter, a process for producing propylene in the present invention will be explained according to the aforementioned embodiments. {First embodiment} First, the steps (1A), (2A), (3A), (4A), and (5A) in the first embodiment are described. [Explanation on the Step (1A)] In a step (1A), an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (F) recycled from a step (4A) are fed into a first reactor, and the raw materials are contacted with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water. . In the present invention, the "first catalyst" in the first embodiment refers to a catalyst which is employed in the first reactor and capable of reacting the ethylene and at least one of methanol and dimethyl ether, thereby producing propylene and olefin of 4 or more carbon atoms. There is no particular limitation on a catalyst used in the reaction as long as the catalyst is a solid catalyst having Bronsted acid, and known catalysts can be used. For example, there may be used solid acid catalysts: clay minerals such as kaolin; a catalyst in which an acid such as sulfuric acid or phosphoric acid is impregnated in or supported on a carrier such as a clay mineral; acid ion exchange resins; zeolites; aluminum phosphates; and mesoporous silica alumina such as A1-MCM41, etc. Among those solid acid catalysts, the solid catalyst having a molecular sieve effect is preferable, and one not' so strong acidity is preferable. Among the solid acid catalysts, when the structure type of zeolites or aluminum phosphates is assigned as a code by the International Zeolite Association (IZA), it may be mentioned by AEI, AET, AEL, AFI, AFO, AFS, AST, ATN, BEA, CAN, CHA, EMT, ERI, EUO, FAU, FER, LEV, LTL, MAZ, MEL, MFI, MOR, MTT, MTW, MWW, OFF, PAU, RHO, STT, TON, etc. In particular, a catalyst having a framework density of 18.0 T/nm3 or less is preferable, and examples thereof include preferably MFI, MEL, MOR, MWW, FAU, BEA, and CHA, more preferably MFI, MEL, MOR, MWW, and CHA, and particularly preferably MFI, MEL, MWW, and CHA. Here, the framework density (unit: T/nm3) refers to the number of T atom (atoms constituting the skeleton of zeolite excluding oxygen atoms) per a unit volume (1 nm3) of zeolite, and this value depends on the structure of zeolite. Further, the solid catalyst is preferably crystalline aluminosilicates, metallosilicates,' crystalline aluminum phosphates, or the like, each of which has micro pores of 0.3 to 0.9 nm in size, a BET specific surface area of 200 to 700 m2/g, and a pore volume of 0,1 to 0.5 g/cc. Here, the size of micro pores refers to the crystallographic free diameter of the channels defined by the International Zeolite Association (IZA). When the pore (channel) is in a circular shape, the size refers to its diameter, and when the pore is in an oval shape, the size refers to its minor axis. The aluminosilicates are preferably those having I Si02/Al203 of 10 or more in a molar ratio. When the molar ratio of Si02/Al203 is too low, durability of the catalyst undesirably deteriorates, thus is not preferable. The upper limit of the molar ratio of Si02/Al203 is generally 10,000 or less. When the molar ratio of Si02/Al203 is higher than the limit, activity of the catalyst deteriorates, thus is not preferable. The molar ratio can be determined by usual methods such as X-ray fluorescence and chemical analyses. The aluminum content in a catalyst can be controlled by the input amount of raw materials when preparing the catalyst, and also Al can be reduced by steaming or the like after the catalyst preparation. A part of aluminum may be replaced by other element such as boron, gallium, or the like, and particularly preferably replaced by boron. The catalyst may be used alone or in a combination of two or more kinds. For the invention, the components mentioned above may be used in the reaction by being palletized/molded using a substance or a binder inactive in the reaction or as a mixture thereof. As the substance or binder inactive in the reaction, there may be exemplified by alumina, aluminazol, silica, silica gel, quartz, or mixtures thereof. The aforementioned catalyst composition is a composition including only the catalytically active component without any substances or binders inactive in the reaction. Meanwhile, the catalyst related to the invention refers to either a catalyst provided as a combination of the catalytically active component and a substance or binder inactive in the reaction when a substance or binder inactive in the reaction is employed, or a catalyst provided as a catalytically active component only when a substance or a binder inactive in the reaction is not employed. The particle size of the catalytically active component used in the invention varies depending on conditions during the synthesis, but usually the mean particle size is 0.01 to 500 (im. When the particle size of the catalyst is too large, a surface area expressing the catalytic activity gets smaller, and when the size is too small, it gives difficulty in handling, thus both cases are not preferable. This mean particle size can be determined by a scanning electro microscope (SEM) or the like. There are no particular limitations on a preparation method of the catalyst used in the invention, and the catalyst can be usually prepared in accordance with the known method called a hydrothermal synthesis. In addition, the composition can be changed by after the hydrothermal synthesis, subjecting an ion exchange, a dealuminization treatment, and a modification by impregnating, supporting, etc. The catalyst used in the invention may be any prepared in accordance with any processes as long as it has the aforementioned "properties and composition when provided in the reaction. There is no particularly limitation on the ethylene as a raw material used in the reaction. For example, there can be arbitrarily used those produced in accordance with various known methods, such as those produced by catalytic cracking or steam cracking of petroleum feedstock, those produced by carrying out an FT (Fisher-Tropsch) synthesis with the use of a hydrogen/CO gas mixture obtained by gasifying coal as a raw material, those obtained by dehydrogenation or oxidative dehydrogenation of ethane, those obtained by metathesis and homologation of propylene, those obtained by an MTO reaction, those obtained by dehydrogenation of ethanol, and the like. Here, the ethylene provided as a mixture including other compounds which are produced in such production process may be used directly as it is, or the purified ethylene may be used. The production origin of at least one of methanol and dimethyl ether used in the reaction as raw material is not particularly limited. For example, there may be mentioned by those obtained by hydrogenation of coal, natural gas, and a hydrogen/CO gas mixture derived from byproducts from iron production, those obtained by modification of plant- derived alcohols, those obtained by fermentation, or those obtained by organic substances such as recycle plastics, urban wastes, or the like. Here, the at least one of methanol and dimethyl ether provided as a mixture including other compounds which are produced in such production process may be used directly as it is, or the purified at least one of methanol and dimethyl ether may be used. The "fluid (F) recycled from step (4A)" refers to a recycled fluid (F) which is obtained through the step (4A) and includes ethylene. The fluid (F) is a part of the hydrocarbon of 2 or less carbon atom-rich fluid (D) in the step (3A). Here, the term "part" indicates the range of 10 to 99 wt% of the amount of the fluid (D), preferably 50 to 95 wt% thereof. Below the range, the flow rate of an ethylene as raw material fed into the first reactor is undesirably increased. Over the range, methane or ethane is accumulated in the first reactor and the recycled fluid, which is not preferable, either. The recycled fluid (F) to the first reactor may include a compound such as methane or ethane which is not involved in the. reaction. A reaction performed in the first reactor is a gas- phase reaction. The gas reactor is not particularly restricted in the form, but usually a continuous fixed bed reactor or fluidized bed reactor is selected and preferably the fixed bed reactor is selected. When the aforementioned catalyst is filled in the fixed bed reactor, particulate substances such as quartz sand, alumina, silica, silica- alumina, etc., which are inactive in the reaction, may be mixed with the catalyst and filled in the reactor to control the temperature distribution in a catalyst layer to be low. In this case, the used amount of particulate substances inactive in the reaction such as quartz sand is not particularly limited. Further, the particulate substance preferably has a similar size with the catalyst regarding the uniform mixing with the catalyst. A reaction temperature refers to a gas temperature of a first reactor inlet. A minimum reaction temperature is generally 300°C or more, preferably 400°C or more, and a maximum reaction temperature is generally 600°C or less, preferably 500°C or less. If the temperature is too low, a reaction rate is low, and thus the raw materials tend to be much left unreacted and the yield of propylene decreases. Meanwhile, if the temperature is too high, the yield of propylene remarkably decreases and the conversion ratio of ethylene is also reduced, thus is not preferable.- Also, the temperature of a first reactor outlet is preferably lower than the temperature of a second reactor outlet at the step outlet by 50°C or more in temperature, for example, more preferably by 50 to 200°C. As the first reactor and the second reactor are operated under such temperature condition, it is possible to obtain propylene with high selectivity in the condition where the recycling amount of ethylene is reduced. A maximum reaction pressure is generally 2 MPa (absolute pressure, hereinafter, refer to the same) or less, preferably 1 MPa or less, more preferably 0.7 MPa or less. A minimum reaction pressure is not limited to a certain value, but generally 1 kPa or more, preferably 50 kPa or more. If the reaction pressure is too high, undesired byproducts such as paraffins, aromatic compounds, or the like are increasingly formed, thereby deteriorating the yield of propylene. If the reaction pressure is too low, the reaction rate tends to be low. The amount of ethylene fed into the first reactor is 0.2 or more in a molar ratio, preferably 0.5 or more, and 5 or less, preferably 2 or less, with respect to the total amount of moles of methanol fed into the reactor and double moles of dimethyl ether fed into the reactor. That is, provided that a feeding molar amount of ethylene is Met, a feeding molar amount of methanol is Mm, and a feeding molar amount of dimethyl ether is Mdm, the Met is 0.2 to 5 times, preferably 0.5 to 2 times the (Mm + 2Mdm). If the feeding concentration ratio is both too low and too high, the reaction is retarded, thus is not preferable. In particular, if the feeding concentration ratio is too high, as ethylene in the reactor outlet increases, its recycling amount increases, thus is not preferable. Here, the feeding concentration ratio can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the reactor or a composition of the mixed fluid. Also, the ethylene and at least one of methanol and dimethyl ether are separately fed into the reactor, or a part or all of the materials are mixed with each other and then fed to the reactor. Of all materials fed into the first reactor, the total concentration (concentration of substrate) of ethylene and at least one of methanol and dimethyl ether is 20 vol% to 80 vol% of the concentration of all materials fed into the first reactor, preferably 30 vol% to 70 vol%. Here, the substrate concentration can .be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the first reactor or a composition of the mixed fluid. If the substrate concentration is too high, aromatic compounds or paraffins are considerably produced, so that the selectivity of propylene tends to deteriorate. On the contrary, if the substrate concentration is too low, a reaction rate becomes low. Accordingly, a great quantity of catalyst is needed and the cost for equipment and service increases due to refining a product or reaction equipment, which is not effective in the cost for equipment. Thus, the reaction substrate is diluted with a diluent gas (mentioned later) so as to satisfy the substrate concentration within the foregoing range. The substrate concentration is controlled by regulating the flow rate of a fluid removed from the process. Adjusting the flow rate of the fluid removed from the process changes the fluid of the diluent gas recycled into the first reactor, thereby controlling the substrate concentration. In the first reactor may be present paraffins, aromatic compounds, vapor, carbon dioxide, carbon monoxide, nitrogen, argon, helium and mixtures thereof, which are inactive gases to the reaction, in addition to ethylene and at least one of methanol and dimethyl ether. Of their diluent gases, the paraffins or aromatic compounds may react slightly depending on reaction conditions. However, their reaction amounts are small, and thus they are defined as a diluent gas. As for the diluent gases, impurities itself contained in the reaction materials may be used, or an additionally prepared diluent gas mixed with the reaction material may be used. The diluent gases may be mixed with the reaction material before being fed into the first reactor or be separately fed into the first reactor from the reaction material. The spatial velocity is preferably between O.lHr-1 and 500Hr_1, more preferably between O.lHr"1 and lOOHr"1. If the spatial velocity is too high, the conversion ratio of the ethylene raw material and at least one of methanol and dimethyl ether becomes low. Further, if the spatial velocity is too low, the amount of catalyst necessary to obtain certain yield is increased, and thus the first reactor needs to be large and byproducts such as aromatic compounds, paraffins, or the like are undesirably produced. Here, the spatial velocity refers to the flow rate of the ethylene raw material per the weight of a catalyst (catalytically active component). The weight of a catalyst refers to the weight of a catalytically active component excluding inactive materials or binders used for fabricating and molding a catalyst. Further, the flow rate refers to the amount of ethylene (weight/hour). With the total amount of the mole flow rate of methanol fed into the first reactor and the double mole flow rate of dimethyl ether fed into the first reactor, the total amount of the mole flow rate of methanol from the first reactor outlet and the double mole flow rate of dimethyl ether from the first reactor outlet is preferably less than 1%, more preferably less than 0.1%. If the amount of methanol or dimethyl ether from the first reactor outlet is considerably increased as its consuming amount is small, it is not simple to refine the olefin product. In order to increase the consuming amount, the reaction temperature is raised or the spatial velocity is brought down. Here, the flow rate of methanol, the flow rate of dimethyl ether, and the flow rate of ethylene which are fed into the first reactor can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the first reactor or a composition of the mixed fluid and measuring the amount of each fluid. The flow rate of methanol, the flow rate of dimethyl ether, and the flow rate of ethylene from the first reactor outlet are calculated by carrying out general quantitative analysis, such as gas chromatography or the like, on the composition of the fluids from the first reactor outlet and measuring the flow rate of the fluids from the first reactor outlet. The conversion ratio of ethylene in the first reactor is generally 30% or more, preferably 40% or more and less than 80%. If the conversion ratio of ethylene is below the range, a large quantity of olefin remains unreacted and the flow rate of the fluid recycling to the first reactor is excessive, thus is not preferable. If the conversion is over the range, undesired byproducts such as paraffin or aromatic compounds are produced, thus is not preferable. The term "conversion ratio of ethylene" mentioned in the present invention refers to a rate of ethylene converted into another compound aside from ethylene and is represented as the following equation: Conversion ratio of ethylene (%) = {(flow rate of ethylene in inlet of first reactor - flow rate of ethylene in outlet of first reactor) / flow rate of ethylene in inlet of first reactor} x 100. The conversion ratio of ethylene may be quantitatively analyzed by a general analysis method, such as gas chromatography or the like, and a flowmeter. The "fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water" refers to an effluent fluid from the first reactor outlet. As the effluent fluid (A) from the first reactor outlet, a mixed gas which includes propylene that is the reaction product, unreacted raw materials, byproducts, and diluents are obtained. The concentration of propylene is generally 5 to 95 wt% of the mixed gas. The unreacted raw materials are generally ethylene. The unreacted raw materials may include at least one of methanol and dimethyl ether depending on reaction conditions. However, it is desirable to perform the reaction under conditions where at least one of methanol and dimethyl ether is not to remain. Accordingly, the product and the unreacted raw materials are simply separated from each other. The product may be olefin of 4 or more carbon atoms, praraffins, aromatic compounds, and water in addition to propylene. [Explanation on the Step (2A)] In a step (2A) , at least one of methanol and dimethyl ether as a raw material and a fluid (G) recycled from a step (5A) are fed into the second reactor, and the raw materials are contacted with the second catalyst, thereby obtaining a fluid (B) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water. In the present invention, the "second catalyst" refers to a catalyst which is employed in the second reactor and capable of reacting the at least one of methanol and dimethyl ether and olefin of 4 or more carbon atoms, thereby producing propylene and olefin of 4 or more carbon atoms. The second catalyst may employ one of those for the first catalyst mentioned in the description on the step (1A). In this case, both the same catalyst in structure and composition as the first catalyst and a different one in structure and/or composition may be used as a second catalyst. In case of using catalysts having a different composition from each other, it is preferable that the molar ratio of SiO2/Al203 in the second catalyst is higher than that of Si02/Al2C>3 in the first catalyst. It is preferable that the molar ratio of Si02/Al203 is high, since the generation of paraffin and aromatic compound is suppressed, but when the molar ratio of Si02/Al203 in the first catalyst is too high, the conversion ratio of ethylene tends to become low. The production origin of at least one of methanol and dimethyl ether used in the reaction as raw material is not .particularly limited. For example, there may be mentioned by those obtained by hydrogenation of coal, natural gas, and a hydrogen/CO gas mixture derived from byproducts from iron production, those obtained by modification of plant- derived alcohols, those obtained by fermentation, or those obtained by organic substances such as recycle plastics, urban wastes, or the like. Here, the at least one of methanol and dimethyl ether provided as a mixture including other compounds which are produced in such production process may be used directly as it is, or the purified at least one of methanol and dimethyl ether may be used. A "fluid (G) recycled from the step (5A)" refers to a recycled fluid (G) obtained at the step (5A). The fluid (G) includes hydrocarbon of 4 or more carbons. The fluid (G) is a part of the hydrocarbon of 4 or more carbon atoms-rich fluid (E) at the step (3A). Here, the term "part" generally indicates the range of 10 to 99 wt% of the amount of the fluid (E), preferably 50 to 95 wt% thereof. Below the range, the amount of olefin is small, thereby decreasing the yield of propylene. Over the range, paraffin contained in the fluid (E) is accumulated and the flow rate of the fluid (B), the flow rate of the fluid (C), and the flow rate of the fluid (G) increase, thereby causing increase of the cost of equipment and service. The hydrocarbon of 4 or more carbon atoms-rich fluid (G) recycled into the second reactor is not limited as long as it includes olefin, and may include paraffin or aromatic compounds. A gas reaction is performed in the second reactor. The gas reactor is not restricted in the form, but generally selected from a continuous fixed bed reactor or a fluidized bed reactor. Preferably, the gas reactor is provided as a fixed bed reactor. When the foregoing catalyst is filled in the fixed bed reactor, particles such as quartz sand, alumina, silica, silica-alumina, etc., which are inactive to the reaction, may be mixed with the catalyst and filled in the reactor to control temperature distribution in a catalyst layer small. In this case, the particles such as quartz sand or the like which is not active to the reaction are not limited with respect to the amount. Further, the particles preferably have a similar size with the catalyst regarding uniformly mixing with the catalyst. A minimum reaction temperature is generally about 300°C or above, preferably 400°C or above, and a maximum reaction temperature is generally 700°C or below, preferably 600°C or below, for the gas temperature of the second .reactor inlet. When the reaction temperature is too low, a reaction rate decreases which causes unreacted raw materials to more likely remain, and also the yield of propylene decreases. On the other hand, when the reaction temperature is too high, the yield of propylene significantly decreases. A maximum reaction pressure is generally 2 MPa (absolute pressure, hereinafter referred as the same) or less, preferably 1 MPa or less, more preferably 0.7 MPa or less. A minimum reaction pressure is not particularly limited, but generally 1 kPa or more, preferably 50 kPa or more. When the reaction pressure is too high, undesired byproducts such as paraffins, aromatic compounds, or the like are increasingly produced, thereby deteriorating the yield of propylene. When the reaction pressure is too low, the reaction rate tends to be low. The amount of olefin of 4 or more carbon atoms fed into the second reactor is 0.2 or more in a molar ratio, preferably 0.5 or more, and 10 or less, preferably 5 or less, with respect to the total amount of moles of methanol fed into the second reactor and double moles of dimethyl ether fed into the reactor. That is, provided that a feeding molar amount of olefin of 4 or more carbon atoms is Mc4, a feeding molar amount of methanol is Mm, and a feeding molar amount of dimethyl ether is Mdm, the Mc4 is 0.2 to 10 times, preferably 0.5 to 5 times the (Mm + 2Mdm). When this feeding concentration ratio is either too low or too high, the reaction slows down, thus is not . preferable. In particular, when the feeding concentration ratio is too low, the amount of olefin raw material consumed is reduced, thus is not preferable. Here, the feeding concentration ratio can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the second reactor or a composition of the mixed fluid. When feeding the olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether to the second reactor, these may be separately fed to the reactor, or a part or all of those may be mixed in advance to be fed to the reactor. Of all materials fed into the second reactor, the total concentration {concentration of substrate) of olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether is 20 vol% to 80 vol% of the concentration of all materials, preferably 30 vol% to 70 vol%. Here, the substrate concentration can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the second reactor or a composition of the mixed fluid. ~ -If - the -substrate concentration is too high, aromatic compounds or paraffins are considerably produced, so that the selectivity of propylene tends to deteriorate. On the contrary, if the substrate concentration is too low, a reaction rate becomes low. Accordingly, a great quantity of catalyst is needed and the cost increases due to refining a product or reaction equipment, which is not effective in cost. Thus, the reaction substrate is diluted with a diluent gas (mentioned later) so as to satisfy the substrate concentration within the foregoing range. The substrate concentration is controlled by regulating the flow rate of a fluid removed from the process. Adjusting the flow rate of the fluid removed from the process changes the fluid of the diluent gas recycled into the second reactor, thereby controlling the substrate concentration. There is a case where the hydrocarbon fluid to be recycled into the second reactor and/or the olefin of 4 or more carbon atoms raw material contain a butadiene compound. The concentration of butadiene in total components to be fed to the second reactor is preferably 2.0 vol% or less. Here, the concentration of butadiene can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fl- uids to be fed to the second reactor or a composition of the mixed fluid. If the concentration of butadiene is high, deterioration by coking of the catalyst becomes fast. The concentration of butadiene is reduced by partial hydrogenation where the fluid is converted into olefins by contacting with a hydrogen adding catalyst. The hydrocarbon fluid recycled into the second reactor may include an aromatic compound. The amount of the aromatic compound contained all gases fed into the second reactor is preferably less than 0.05 in molar ratio, with respect to the amount of the olefin of 4 or more carbon atoms contained all gases fed into the second reactor. A ratio of the amount of the aromatic compound to the amount of the olefin of 4 or more carbon atoms can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the second reactor or a composition of the mixed fluid. If the concentration of the aromatic compound is high, the aromatic compound reacts with at least one of methanol and dimethyl ether in the second reactor, and thus at least one of methanol and dimethyl ether is undesirably consumed more than needed. The concentration of the aromatic compound is decreased by a separation method by distillation. In the second reactor, there may be paraffins, aromatic compounds, vapor, carbon dioxide, carbon monoxide, nitrogen, argon, helium, and mixtures thereof, which are inert gases to the reaction, in addition to the olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether. Of these diluent gases, paraffins and aromatic compounds may slightly react depending on the reaction conditions, but these are still referred as diluent gases as a small amount of reaction is only taking place. As the diluent gases, impurities contained in the reaction materials may be directly used, or a mixture of additionally prepared diluent gases with the reaction materials may be used. The diluent gases may be mixed with the reaction materials before a feeding to the second reactor or may be separately fed to the second reactor from the reaction materials. The spatial velocity is preferably between O.lHr"1 and 500Hr_1, more preferably between O.lHr"1 and lOOHr"1. When the spatial velocity is too high, conversion ratio of the olefin raw material and at least one of methanol and dimethyl ether becomes low and sufficient selectivity of propylene cannot be obtained. When the spatial velocity is too low, it is not preferable because the amount of catalyst required to obtain certain yield is increased and the second reactor has to be made too large, " and also byproducts such as aromatic compounds, paraffins, or the like are undesirably produced, thereby deteriorating the selectivity of propylene. Here, the spatial velocity refers to the flow rate of the olefin of 4 or more carbon atoms serving as the reaction raw material per the catalyst (catalytically active component) weight. Here, the catalyst weight refers to the weight of a catalytically active component not including inactive components or binders used for palletizing/molding a catalyst. Further, the flow rate refers to the flow rate (weight/hour) of the olefin of 4 or more carbon atoms. A sum of the molar flow rate of methanol and twice the molar flow rate of dimethyl ether in the second reactor outlet, with respect to the sum of the molar flow rate of methanol and twice the molar flow rate of dimethyl ether which are to be fed to the second reactor, is preferably less than 1%, and more preferably less than 0.1%. When a small amount of methanol and dimethyl ether in the reactor is consumed and the amount of methanol and dimethyl ether in the reactor outlet is too much increased, it becomes difficult to purify the olefin product. In order to increase the consuming amount of methanol and dimethyl ether, the reaction temperature may be increased or the spatial velocity may be brought down.With the total mole flow rate of olefin of 4 or more carbon atoms fed into the second reactor, the total mole flow rate of olefin of 4 or more carbon atoms from the second reactor outlet is 20% or more and less than 70%, preferably 25% or more and less than 60%. When the consuming amount of the olefin of 4 or more carbon atoms in the reactor is too small, it is not preferable because the amount of olefin remaining unreacted increases, and thus the flow rate of the fluid to be recycled into the second reactor undesirably becomes great. On the other hand, when the amount consumed is too much, it is also not preferable because byproducts such as paraffin, aromatic compounds, or the like, are produced, and thus the yield of propylene decreases. In order to adjust the consuming amount of the olefin of 4 or more carbon atoms in the reactor, the reaction temperature or the spatial velocity may be appropriately selected. Here, the flow rates of methanol, dimethyl ether, and olefin of 4 or more carbon atoms which are to be fed to the second reactor can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the reactor or a composition of the mixed fluid and then measuring the flow rate of each fluid. The flow rates of methanol, dimethyl ether, and olefin of 4 or more carbon atoms in the second reactor outlet are realized by carrying out a general analysis such as gas chromatography, on the composition of reactor outlet fluids and then measuring or calculating the flow rate of the second reactor outlet fluids. The "fluid (B) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water" refers to an effluent fluid from the second reactor outlet. As the effluent fluid (B) from the second reactor outlet, there obtained a gas mixture including propylene which is the reaction product, unreacted raw materials, byproducts, and diluents. The concentration of propylene in the gas mixture is usually from 5 to 95 wt%. The unreacted raw materials are usually olefin of 4 or more carbon atoms. The unreacted raw materials may include at least one of methanol and dimethyl ether depending on reaction conditions, but it is preferable to carry out the reaction under conditions of giving no remaining at least one of methanol and dimethyl ether. In this manner, the separation of the reaction product and the unreacted raw materials becomes .simple. The byproducts may be ethylene, olefin of 4 or more carbon atoms, praraffins, aromatic compounds, and water. [Explanation on the Step (3A)] In the step (3A), the fluid (C) where the fluid (B) obtained in the step (2A) is mixed, is separated into a hydrocarbon of 2 or less carbon atom-rich fluid (D), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (E), and a water-rich fluid. The amount of ethylene contained in the mixed fluid (C) is preferably less than 2.0, more preferably less than 1.5, and still more preferably less than 1.0, in a weight ratio with respect to the amount of propylene contained in the mixed fluid (C) . Accordingly, the cost of equipment and service for the process may be considerably reduced. A weight ratio of ethylene contained in the fluid (C) to propylene therein can be realized by carrying out a general quantitative analysis such as gas chromatography, on the composition of the fluid. Also, the weight ratio of ethylene of the fluid (C) to propylene thereof is changed by adjusting reaction conditions such as the reaction temperature of the first reactor and/or the second reactor, the spatial velocity thereof, or the like. The fluid (C) is separated by cooling, compressing, distillation,, etc. into the hydrocarbon of 2 or less carbon atom-rich fluid (D), the propylene-rich fluid, the hydrocarbon of 4 or more carbon atoms-rich fluid (E), and the water-rich fluid. Here, the respective fluids are not limited to one fluid but may be a plurality of fluids. For example, the hydrocarbon of 2 or less carbon atom-rich fluid (D) may be a single fluid which includes methane, ethylene, and ethane, or may be two fluids which are a methane-rich fluid and an ethylene and ethane-rich fluid. As necessary, quenching, alkaline cleaning, dehydration, etc. are preferably carried out. If the fluid (C) includes an oxygen containing compound, at least a part of the oxygen containing compound is removed by quenching. If an effluent gas from the reactor outlet includes an acid gas such as carbon dioxide or the like, at least a part of the acid gas is removed by alkaline cleaning. The water is condensed mostly by compressing and cooling, thereby separating. Remaining moisture is preferably removed by an absorbent, e.g., molecular sieve. The water removed by condensing and/or absorbing may be provided to a waste water treatment process such as active sludge or the like, or used for the process. If the process is close to a steam cracking process, the water is preferably used as a steam source of a cracker. In addition, the water is recycled into the first reactor of the step- (1A) and/or the second reactor of the step (2A) and then used as a diluent gas. The propylene-rich fluid is preferably brought into a purification step such as distillation so as to obtain propylene with higher purity. The purity of propylene is 95% or more, preferably 99% or more, and more preferably 99.9% or more. The produced propylene may be used for a raw material of propylene derivatives which are generally produced. For example, the propylene can be used for producing, for example, acrylonitrile by ammoxidation; acrolein, acrylic acid, and acrylate ester, by selective oxidation; oxo alcohols such as normal butanol and 2-ethylhexanol by an oxo reaction; polypropylene by a polymerization of propylene; propylene oxide, propylene glycol, and the like, by selective oxidation of propylene. In addition, acetone can be produced according to the Wacker reaction, and methyl isobutyl ketone can be produced from the acetone. Also from the acetone, acetonecyanhydrin can be produced which can be finally converted into methyl methacrylate. The propylene can be used to produce isopropyl alcohol by hydration of propylene. Further, phenol, bisphenol A, and polycarbonate resins can be produced with the use of cumene produced by alkylating benzene as a raw material. [Explanation on the Step (4A)] In the step (4A), a fluid (F), which is a part of the fluid (D) at the step (3A), is recycled into the first reactor, and the remaining fluid is removed from the process of the present invention (hereinafter, also may be referred to as the "present process") . Here, the fluid (D) may not be introduced to the separation process but just separated into the fluid (F) to be recycled and the fluid to be removed. Also, the fluid (D) may be introduced to the separation process and a fluid of which the concentration of ethylene is increased more than in the fluid (D) is recycled into the first reactor. The removed fluid may be refined to collect available substances such as ethylene or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. The term "removed from the process" means that recycling into the first reactor or into the second reactor is not taking place. [Explanation on Step (5A)] In the step (5A) , a fluid (G) , which is a part of the fluid (E) at the step (3A), is recycled into the second reactor, and the remaining fluid is removed from the process. Here, the fluid (E) may not be introduced to the separation process but just separated into the fluid (G) to be recycled and the fluid to be removed. Also, the fluid (E) may be introduced to the separation process and a fluid of which the concentration of butene is increased more than in the fluid (E) is recycled into the second reactor. The removed fluid may be refined to collect available substances such as butene, aromatic compounds, or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. {Second embodiment} Next, the steps (1B), (2B), (3B), (4B), and (5B) in the second embodiment are described. [Explanation on Step (IB)] In the step (1B) , an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (L) recycled from the step (4B) are fed into a first reactor, and the raw materials are contacted with a first catalyst, thereby obtaining a fluid (A) which includes propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound and a water containing fluid. In the step (1B), descriptions on The "fluid (L) recycled from step (4B)" refers to a recycled fluid (L) which is obtained through the step (4B) and includes ethylene. The fluid (L) is a part of the hydrocarbon of 2 or less carbon atom-rich fluid (J) in the step (3B). Here, the term "part" generally indicates the range of 10 to 99 wt% of the flow rate of the fluid (J), preferably 50 to 95 wt% thereof. Below the range, the flow rate of an ethylene raw material fed into the first reactor is undesirably increased. Over the range, methane or ethane is accumulated in the first reactor and the recycled fluid, which is not preferable, either. The recycled fluid (L) recycled into the first reactor may include methane or ethane. [Description of the Step (2B)] In the step (2B), the fluid (A) obtained at the step (IB), at least one of methanol and dimethyl ether as a raw material, and a fluid (M) to be recycled from the step (5B) are fed into a second reactor, and the raw materials are contacted with a second catalyst, thereby obtaining a fluid (I) which includes propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound and a water. In the step (2B), descriptions on A "fluid (M) recycled from the step (5B)" refers to a recycled fluid (M) obtained at the step (5B) and a fluid which includes hydrocarbon of 4 or more carbon atoms. The fluid (M) is a part of the hydrocarbon of 4 or more carbon atoms-rich fluid (K) at the step (3B). Here, the term "part" generally indicates the range of 10 to 99 wt% of the flow rate of the fluid (K), preferably 50 to 95 wt% thereof Below the range, the amount of olefin recycled in the reactor is small, thereby decreasing the yield of propylene Over the range, paraffin contained in the fluid The "fluid (I) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compounds, and water" refers to an effluent fluid from the second reactor outlet at the step (2B). As the fluid (I) from the second reactor outlet, there obtained a gas mixture including propylene which is the reaction product, unreacted raw materials, byproducts, and diluents. The concentration of propylene in the gas mixture is usually from 5 to 95 wt%. The unreacted raw materials are usually olefin of 4 or more carbon atoms. The unreacted raw materials may include at least one of methanol and dimethyl ether depending on reaction conditions, but it is preferable to carry out the reaction under conditions of giving no remaining at least one of methanol and dimethyl ether. In this manner, the separation of the reaction product and the unreacted raw materials becomes simple. The byproducts may be ethylene, olefin of 4 or more carbon atoms, praraffins, aromatic compounds, and water. The amount of ethylene contained in the fluid (I) is preferably less than 2.0, more preferably less than 1.5, and still more preferably less than 1.0, in a weight ratio with respect to the amount of propylene contained in the mixed fluid (I). Accordingly, the cost of equipment and service for the process may be considerably reduced. A weight ratio of ethylene contained in the fluid (I) to propylene therein can be realized by carrying out a general quantitative analysis such as gas chromatography, on the composition of the fluid. Also, the weight ratio of ethylene of the fluid (I) to propylene thereof is changed by adjusting reaction conditions such as the reaction temperature of the first reactor and/or the second reactor, the spatial velocity thereof, or the like. [Explanation on Step (3B)] In the step (3B), the fluid (I) obtained in the step (2B) is separated into a hydrocarbon of 2 or less carbon atom-rich fluid (J), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (K) , and a water-rich fluid. The fluid (I) obtained at the step (2B) is separated by cooling, compressing, distillation, etc. into the hydrocarbon of 2 or less carbon atom-rich fluid (J), the propylene-rich fluid, the hydrocarbon of 4 or more carbon atoms-rich fluid (K), and the water-rich fluid. Here, the respective fluids are not limited to one fluid but may be a plurality of fluids. For example, the hydrocarbon of 2 or less carbon atom-rich fluid (J) may be a single fluid which includes methane, ethylene, and ethane, or may be two fluids which are a methane-rich fluid and an ethylene and ethane-rich fluid. As necessary, quenching, alkaline cleaning, dehydration, etc. are preferably carried out. If the fluid (I) includes an oxygen containing compound, at least a part of the oxygen containing compound is removed by quenching. If an effluent gas from the reactor outlet includes an acid gas such as carbon dioxide or the like, at least a part of the acid gas is removed by alkaline cleaning. The water is condensed mostly by compressing and cooling, thereby separating. Remaining moisture is preferably removed by an absorbent, e.g., molecular sieve. The water removed by condensing and/or absorbing may be provided to a waste water treatment process to treat active sludge or the like, or used for the process. If the process is close to a steam cracking process, the water is preferably used as a steam source of a cracker. In addition, the water is recycled into the first reactor of the step (IB) and/or the second reactor of the step (2B) and then used as a diluent gas. The propylene-rich fluid is desirably refined by a purifying process such as distillation or the like to give propylene with high purity. The purity of propylene is 95% or more, preferably 99% or more, more preferably 99.9% or more. The produced propylene may be used for a raw material of propylene derivatives which are generally produced. The propylene can be used for producing, for example, acrylonitrile by ammoxidation; acrolein, acrylic acid, and acrylate ester, by selective oxidation; oxo alcohols such as normal butanol and 2-ethylhexanol by an oxo reaction; polypropylene by a polymerization of propylene; propylene oxide, propylene glycol, and the like, by selective oxidation of propylene. In addition, acetone can be produced according to the Wacker reaction, and methyl isobutyl ketone can be produced from the acetone. Also from the acetone, acetonecyanhydrin can be produced which can be finally converted into methyl methacrylate. The propylene can be used to produce isopropyl alcohol by hydration of propylene. Further, phenol, bisphenol A, and polycarbonate resins can be produced with the use of cumene produced by alkylating benzene as a raw material. [Explanation on Step (4B)] In the step (4B), a fluid (L), which is a part of the fluid (J) at the step (3B) is recycled into the first reactor, and the remaining fluid is removed from the process. Here, the fluid (J) may not be introduced to the separation process but just separated into the fluid (L) to be recycled and the fluid to be removed. Also, the fluid (J) may be introduced to the separation process and a fluid of which the concentration of ethylene is increased more than in the fluid (J) is recycled into the first reactor. The removed fluid may be refined to collect available substances such as ethylene or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. The term "removed from the process" means that recycling into the first reactor or into the second reactor is not taking place. [Explanation on Step (5B)] In the step (5B), a fluid (M) , which is a part of the fluid (K) at the step (3B) is recycled into the second reactor, and the remaining fluid is removed from the process. Here, the fluid (K) may not be introduced to the separation process but just separated into the fluid (M) to be recycled and the fluid to be removed. Also, the fluid (K) may be introduced to the separation process and a fluid of which the concentration of butene is increased more than in the fluid (K) is recycled into the second reactor. The removed fluid may be refined to collect available substances such a-s butene, aromatic compounds, or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. {Introduction of reaction raw material in first and second embodiments) According to the present invention, the fluid which contains olefin of 4 or more carbon atoms may be fed into the second reactor at the step (2A) or (2B) as a new raw material to produce propylene. A olefin of 4 or more carbon atoms as a raw material is not limited to a specific one. For example, the olefin of 4 or more carbon atoms as a raw material may be used with olefin of 4 or more carbon atoms, particularly any one of olefins of 4 to 10 carbon atoms, obtained by any one of the following known processes: catalytic cracking or steam cracking from a petroleum feedstock {product: BB distillate, C4 raffinate-1, C4 raffinate-2, etc.); carrying out Fisher- Tropsch (FT) synthesis on a hydrogen/CO gas mixture as a raw material obtained by gasifying coal; dehydrogenating or oxidatively dehydrogenating paraffin of 4 or more carbon atoms; the MTO process; dehydrating alcohol; hydrogenating diene compounds of 4 or more carbon atoms; etc. Here, the olefin of 4 or more carbon atoms raw material may be used with a mixture itself of olefin of 4 or more carbon atoms and other compounds formed due to the producing processes or refined one. An olefin raw material which includes paraffins is preferably used. The paraffins function as a diluent gas, so that it is not difficult to control the reaction temperature. Further, the raw material including paraffins is not expensive. An olefin raw material which includes normal butane and/or isobutane is more preferable. For example, there are BB distillate, C4 raffinate-1, and C4 raffinate-2. Here, a distillate includes a large deal of butadiene, and thus it is contacted with a hydrogen adding catalyst to decrease the concentration of butadiene. Then, the product thus obtained is used as a raw material. The supplied amount of a fluid which contains olefin of 4 or more carbon atoms from an outside process is not limited. {Properties of steps (1A) to (5A) and steps (IB) to (5B)} With respect to properties of the steps (1A) to (5A) according to the first embodiment, hydrocarbon of 3 or less carbon atom, such as ethylene, propylene, or the like, produced in the first reactor is not fed into the second reactor. Thus, propylene produced in the first reactor and in the second reactor, respectively, is efficiently removed as a product. Meanwhile, with respect to properties of the steps (IB) to (5B) according to the second embodiment, as ethylene or propylene produced in the first reactor is fed into the second reactor, a part of the propylene reacts to be converted into another compound. However, since the flow rate of the fluid (I) fed into a separation and purification system at the step (3B) is considerably little as compared with the flow rate of the fluid (C) fed into a separation and purification system at the step (3A), the cost of equipment and service for the separation and purification system is low. Thus, as both embodiments have their own properties, proper one may be selected from the processes considering the processing cost or the yield of propylene. {Third embodiment} In the step (1C), an ethylene as a raw material and a fluid (P) to be recycled from the step (4C) are fed into a first reactor, and the raw materials are contacted with an ethylene dimerization catalyst, thereby obtaining a fluid (Q) which contains hydrocarbon of 4 carbon atoms. The "ethylene dimerization catalyst" (hereinafter, referred to as just a "catalyst" at the step (1C)) used in the reaction involved in the present invention refers to a catalyst which is capable of producing hydrocarbon of 4 carbon atoms (butane) with an ethylene as a raw material. The catalyst is not limited to specific one but may be used with known catalysts as long as one has a catalytic ability with respect to the reaction where butane is produced by dimerization of ethylene. - The eatalyst refers to both a complex catalyst and a solid catalyst. The complex catalyst, for example, includes a titanium containing catalyst which such as tetrabutoxytitanium triethylaluminum composite catalyst, a nickel containing catalyst, a palladium containing catalyst, etc. Meanwhile, the solid catalyst includes a nickel containing catalyst such as a nickel oxide-supported catalyst, etc. The complex catalyst is preferably used in the reaction under the liquid condition, and the solid catalyst is preferably used in the reaction, under the gaseous condition. One kind of catalyst may be independently used, or a mixture two or more kinds of catalysts may be used. An ethylene raw material used in the reaction is not particularly limited. For example, the ethylene raw material may be used with any one obtained by one of the following known processes: catalytic cracking or steam cracking from a petroleum feedstock; carrying out Fisher- Tropsch (FT) synthesis on a hydrogen/CO gas mixture raw material obtained by gasifying coal; dehydrogenating or oxidatively dehydrogenating ethane; metathesis and homologation of propylene; the MTO process; dehydrating ethanol; etc. Here, the ethylene raw material may be used with a mixture itself of ethylene and other compounds formed due to the producing processes or refined one. The "fluid (P) recycled from step (4C)" refers to a fluid (P) which is obtained at the step (3C) and includes ethylene. The fluid (P) is a part of the hydrocarbon of 2 or less carbon atom-rich fluid (T) and is to be recycled into the first reactor. Here, the term "part" indicates the range of 10 to 99 wt% of the amount of the fluid (T), preferably 50 to 95 wt% thereof. Below the range, the amount of the ethylene raw material fed into the first reactor is undesirably increased. Over the range, methane or ethane is accumulated in the first reactor and the recycled fluid, which is not preferable, either. The recycled fluid (P) into the first reactor may include a compound such as methane or ethane which is not involved in the reaction. Reaction conditions are changed depending on the type of reaction or a catalyst. Generally, in the reaction with a complex catalyst under the liquid condition, a reaction temperature of 300°C or less, for example 20 to 200°C, and a reaction pressure of 0.5 MPa or more, for example 1.0 to 5.0 MPa are preferable. In the reaction with a solid catalyst under the gaseous condition, a reaction temperature of 200°C or more, for example 300 to 700°C, and a reaction pressure of 1 MPa or less, for example 0.1 to 0.5 MPa are preferable. In the reaction under the liquid condition, a solvent is used for the reaction but the butene product is also available as a solvent. The solvent is not limited as long as it is inactive in the reaction, but paraffins are preferable. The concentration of the solvent is less than 90 wt% of the total concentration, for example, preferably 0 to 50 wt%. If the concentration of the solvent is too high, the reaction rate is undesirably retarded. In the reaction under the gaseous condition, a diluent gas may be used. The diluent gas is not particularly limited in its kind as long as it is inactive in the reaction, which includes paraffins, aromatic compounds, vapor, carbon dioxide, carbon monoxide, nitrogen, argon, helium and mixtures thereof. The concentration of the diluent gas is less than 90 vol% of the total- concentration, for example, preferably 0 to 80 vol%. If the concentration of the diluent gas is too high, the reaction rate is undesirably retarded. Here, the concentration of the solvent and the concentratior of the diluent gas may be obtained by a general analysis method such as gas chromatography or the like. The consuming amount of ethylene is preferably 50% or more with the amount of the ethylene fed into the first reactor. If the consuming amount of ethylene is little, the recycling amount of unreacted ethylene is undesirably increased. In order to increase the consuming amount, the reaction temperature or the reaction pressure is raised or the amount of catalyst is increased. The "fluid (Q) which contains hydrocarbon of 4 carbon atoms" refers to an effluent fluid from the first reactor outlet. The effluent fluid (Q) from the first reactor generally includes unreacted ethylene, hexene of byproducts, or the like in addition to the target product of butene. In the reaction under the liquid condition, a stop to separate the catalyst is necessary. However, an> other separation is not performed during the step-and ^he fluid which contains ethylene, butene, and hexane is introduced into the second reactor at the step 2C. Instead, the unreacted ethylene may be separated by a typical separation method such as distillation or the like and the separated ethylene is recycled into the first reactor, and the remaining fluid is introduced into the second reactor at the step (2C) . Further, a part of the fluid (Q), for example 0 to 80%, may not be fed into the second reactor at the step (2C) but removed from the process of the present invention {hereinafter, referred to as "the process"). In this case, the removed fluid is refined to separate butene, and the separated butene may be preferably used for other purposes. One of the purposes is a raw material for producing butadiene by oxidative dehydrogenation or dehydrogenation. The term "removed from the process" means that recycling into the first reactor or into the second reactor is not taking place. [Explanation on Step (2C)] In the step (2C), the fluid (Q) from the step (1C), the fluid (R) recycled from the step The "propylene production catalyst" (hereinafter, referred to as just "catalyst" in the step (2C)) mentioned in the present invention refers to a catalyst which is capable of producing propylene from olefin of 4 or more carbon atoms, at least one of methanol and dimethyl ether. [Catalyst] There is no particular limitation on a catalyst used in the reaction related to the invention as long as the catalyst is a solid catalyst having Bronsted acid, and examples thereof include solid acid catalysts: clay minerals such as kaolin; a catalyst in which an acid such as sulfuric acid or phosphoric acid is impregnated in or supported on a carrier such as a clay mineral; acid ion exchange resins; zeolites; aluminum phosphates; and mesoporous silica alumina such as A1-MCM41, etc. Among those solid acid catalysts, the solid catalyst having a molecular sieve effect is preferable and one not so strong acidity is preferable. Among the solid acid catalysts, when the structure type of zeolites or aluminum phosphates is assigned as a code by the International Zeolite Association (I2A), it may be mentioned by AEI, AET, AEL, AFI, AFO, AFS, AST, ATN, BEA, CAN, CHA, EMT, .ERI, EUO, FAU, FER, LEV, LTL, MAZ, MEL, MFI, MOR, MTT, MTW, MWW, OFF, PAU, RHO, STT, TON, etc. In particular, a catalyst having a framework density of 18.0 T/nm3 or less is preferable, and examples thereof include preferably MFI, MEL, MOR, MWW, FAU, BEA, and CHA, more preferably MFI, MEL, MOR, MWW, and CHA, and particularly preferably MFI, MEL, MWW, and CHA. Here, the framework density {unit: T/nm3) refers to the number of T atom {atoms constituting the skeleton of zeolite excluding oxygen atoms) per a unit volume (1 nm3) of zeolite, and this value depends on the structure of zeolite. Further, the solid catalyst is preferably crystalline aluminosilicates, metallosilicates, crystalline aluminum phosphates, or the like, which has micro pores having 0.3 to 0.9 nm in size, a BET specific surface area between 200 and 700 m2/g, and a pore volume between 0.1 and 0.5 g/ml. Here, the size of micro pores refers to the crystallographic free diameter of the channels defined by the International Zeolite Association (IZA). When the pore (channel) is in a circular shape, the size refers to its diameter, and when the pore is in an oval shape, the size refers to its minor axis. The aluminosilicates are preferably those having Si02/Al203 of 10 or more in a molar ratio. When the molar ratio of Si02/Al203 is too low, durability of the catalyst undesirably deteriorates, thus is not preferable. The upper limit of the molar ratio of Si02/Al203 is generally 10,000 or less. When the molar ratio of Si02/Al203 is higher than the limit, activity of the catalyst deteriorates, thus is not preferable. The molar ratio can be determined by usual methods such as X-ray fluorescence and chemical analyses. The aluminum content in a catalyst can be controlled by the input amount of raw materials when preparing the catalyst, and also A1 can be reduced by steaming or the like after the catalyst preparation. A part of aluminum may be replaced by other element such as boron, gallium, or the like, and particularly preferably replaced by boron. The catalyst may be used alone or in a combination of two or more kinds. For the invention, the components may be used in the reaction by being palletized/molded using a substance or binder inactive in the reaction or as a mixture thereof. As the substance or binder inactive in the reaction, there may be exemplified by alumina, aluminazol, silica, silica gel, quartz, or mixtures thereof. The aforementioned catalyst composition is a composition including only the catalytically active component without any substances or binders inactive in the reaction. Meanwhile, the catalyst related to the invention refers to either a catalyst provided as a combination of the catalytically active component and a substance or binder inactive in the reaction when a substance or binder inactive in the reaction is employed, or a catalyst provided as a catalytically active component only when a substance or a binder inactive in the reaction is not employed. The particle size of the catalytically active component used in the invention varies depending on conditions during the synthesis, but usually the mean particle size is between 0.01 and 500 |im. When the particle size of the catalyst is too large, a surface area specifying the catalytic activity gets smaller, and when the size is too small, it gives difficulty in handling, thus both cases are not preferable. This mean particle size can be determined by a scanning electro microscope (SEM) or the like. There are no particular limitations on a preparation method of the catalyst used in the invention, and the catalyst can be usually prepared in accordance with the known method called a hydrothermal synthesis. In addition, the composition can be changed by after the hydrothermal synthesis, subjecting an ion exchange, a dealuminization treatment, and a modification by impregnating, supporting, etc. The catalyst used in the invention may be any prepared in accordance with any processes as long as it has the aforementioned properties and composition when provided in the reaction. With respect to a catalyst, the "ethylene dimerization catalyst" preferably employs a complex catalyst which contains titanium or nickel, and the "propylene production catalyst" employs the composition of a catalyst which has an MFI structure or an MWW structure. The production origin of at least one of methanol and dimethyl ether used in the reaction as raw material is not particularly limited. For example, there may be mentioned by those obtained by hydrogenation of coal, natural gas, and a hydrogen/CO gas mixture derived from byproducts from iron production, those obtained by modification of plant- derived alcohols, those obtained by fermentation, or those obtained by organic substances such as recycle plastics, urban wastes, or the like. Here, the at least one of methanol and dimethyl ether provided as a mixture including other compounds which are produced in such production process may be used directly as it is, or the purified at least one of methanol and dimethyl ether may be used. The "fluid (R) recycled from step (5C)" refers to a recycled fluid (R) which is obtained at the step (5C) and a hydrocarbon of 4 or more carbon atoms-rich fluid. The fluid (R) is a part of the hydrocarbon of 4 or more carbon atoms-rich fluid (U) at the step (3C) and recycled to the second reactor. Here, the term "part" usually indicates the range of 10 to 99 wt% of the amount of the fluid (U), preferably 50 to 95 wt% thereof. If the ratio of the fluid (R) is below the range, the amount of olefin of 4 or more carbon atoms fed into the second reactor is undesirably increased, and thus the yield of propylene is decreased. Over the range, paraffin is accumulated in the reactor and the recycled fluid, which is not preferable, either. The recycled fluid (R) in the second reactor is not limited as long as it contains olefin and may include paraffin or aromatic compound. A gas reaction is performed in the second reactor. The gas reactor is not particularly restricted in the form, but usually a continuous fixed bed reactor or fluidized bed reactor is selected and preferably the fixed bed reactor is selected. When the aforementioned catalyst is filled in the fixed bed reactor, particulate substances such as quartz sand, alumina, silica, silica-alumina, etc., which are inactive in the reaction, may be mixed with the catalyst and filled in the reactor to control the temperature distribution in a catalyst layer to be low. In this case, the used amount of particulate substances inactive in the reaction such as quartz sand is not particularly limited. Further, the particulate substance preferably has a similar size with the catalyst regarding the uniform mixing with the catalyst. A reaction temperature refers to a gas temperature of a first reactor inlet. A minimum reaction temperature is generally about 300°C or above, preferably 400°C or above, and a maximum reaction temperature is generally 700°C or below, preferably 600°C or below, for the gas temperature of the reactor inlet. When the reaction temperature is too low, a reaction rate decreases which causes unreacted raw materials to more likely remain, and also the yield of propylene decreases. On the other hand, when the reaction temperature is too high, the yield of propylene significantly decreases. A maximum reaction pressure is generally 2MPa (absolute pressure, hereinafter, refer to the same) or less, preferably 1 MPa or less, more preferably 0.7 MPa or less. A minimum reaction pressure is not limited to a certain value, but generally 1 kPa or more, preferably 50 kPa or more. If the reaction pressure is too high, undesired byproducts such as paraffins, aromatic compounds, or- the like are increasingly formed, thereby deteriorating the yield of propylene. If the reaction pressure is too low, the reaction rate tends to be low. The amount of olefin of 4 or more carbon atoms fed to the second reactor is, in a molar ratio, 0.2 or more, preferably 0.5 or more to 10 or less, preferably 5 or less, with respect to the sum of number of moles of methanol and twice the number of moles of dimethyl ether which are to be fed to the reactor. That is, provided that a feeding molar amount of olefin of 4 or more carbon atoms is Mc4, a feeding molar amount of methanol is Mm, and a feeding molar amount of dimethyl ether is Mdm, the Mc4 is 0.2 to 10 times, preferably 0.5 to 5 times the (Mm + 2Mdm). When this feeding concentration ratio is either too low or too high, the reaction slows down, thus is not preferable. In particular, when the feeding concentration ratio is too low, the amount of olefin raw material consumed is reduced, thus is not preferable. Here, the feeding concentration ratio can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the reactor or a composition of the mixed fluid. When feeding the olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether to the reactor, these may be separately fed to the reactor, or a part or all of those may be mixed in advance to be fed to the reactor. Of all materials fed into the second reactor, the total concentration (substrate concentration) of olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether is preferably 20 to 80 vol%, and more preferably 30 to 70 vol%, of the total concentration. Here, the substrate concentration can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the reactor or a composition of the mixed fluid. When the substrate concentration is too high, aromatic compounds or paraffins are considerably produced, so that the selectivity of propylene tends to deteriorate. On the contrary, when the substrate concentration is too low, a reaction rate becomes low, so that a large amount of catalyst is needed further resulting in a cost increase for purifying products and building reaction equipments, thereby being uneconomical. Accordingly, in order to give a substrate concentration in the above range, the reaction substrate is diluted with the use of a diluent gas described later. A method of regulating the flow rate of a fluid removed from the process can be employed as the method for controlling the substrate concentration. That is, the substrate concentration can be changed by adjusting the flow rate of a fluid removed from the process which then changes the flow rate of a diluent gas to be recycled into the reactor. The fluid (R) recycled into the second reactor and/or a fluid of the olefin of 4 or more carbon atoms raw material provided from an outside process may contain a butadiene compound. The concentration of butadiene is preferably 2.0 vol% or less of all materials fed into the second reactor. Here, the concentration of butadiene can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the second reactor or a composition of the mixed fluid. When the concentration of butadiene is high, deterioration in catalyst by coking becomes fast. As the method of reducing the butadiene concentration, there may be employed a partial hydrogenation method comprising bringing the fluid into contact with a partial hydrogenation catalyst to be converted into olefins. The fluid (R) recycled into the second reactor may include an aromatic compound. The total amount of the aromatic compound contained in all gases fed to the second reactor is preferably less than 0.05 in a molar ratio, with respect to the amount of the olefin of 4 or more carbon atoms contained in all gases fed to the second reactor. A ratio of the amount of the aromatic compound to the amount of the olefin of 4 or more carbon atoms can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the second reactor or a composition of the mixed fluid. When the concentration of the aromatic compound is high, at least one of methanol and dimethyl ether in the second reactor react (s) with the aromatic compound thereby spending more than needed amount of at least one of methanol and dimethyl ether, thus is not preferable. As the method of reducing the concentration of the aromatic compound, there may be employed a separation process by distillation. In the second reactor, there may be paraffins, aromatic compounds, vapor, carbon dioxide, carbon monoxide, nitrogen, argon, helium, and mixtures thereof, which are inert gases to the reaction, in addition to the olefin of 4 or more carbon atoms and at least one of methanol and dimethyl ether. Of these diluent gases, paraffins and aromatic compounds may slightly react depending on the reaction conditions, but these are still referred as diluent gases as a small amount of reaction is only taking place. As the diluent gases, impurities contained in the reaction materials may be directly used, or a mixture of additionally prepared diluent gases with the reaction materials may be used. The diluent gases may be mixed with the reaction materials before a feeding to the second reactor or may be separately fed to the second reactor from the reaction materials. The spatial velocity is preferably between O.lHr"1 and 500Hr-1, more preferably between O.lHr"1 and lOOHr"1. When the spatial velocity is too high, conversion ratio of the olefin raw material and at least one of methanol and dimethyl ether becomes low and sufficient selectivity of propylene cannot be obtained. When the spatial velocity is too low, it is not preferable because the amount of catalyst required to obtain certain yield is increased and the reactor has to be made too large, and also byproducts such as aromatic compounds, paraffins, or the like are undesirably produced, thereby deteriorating the selectivity. Here, the spatial velocity refers to the flow rate of the olefin of 4 or more carbon atoms serving as the reaction raw material per the catalyst (catalytically active component) weight. Here, the catalyst weight refers to the weight of a catalytically active component not including inactive components or binders used for palletizing/molding a catalyst. Further, the flow rate refers to the flow rate (weight/hour) of the olefin of 4 or more carbon atoms. CConsuming Amount of raw material in Reaction> A sum of the molar flow rate of methanol and twice the molar flow rate of dimethyl ether in the second reactor outlet, with respect to the sum of the molar flow rate of methanol and twice the molar flow rate of dimethyl ether which are to be fed to the second reactor, is preferably less than 1%, and more preferably less than 0.1%. When a small amount of methanol and dimethyl ether in the reactor is consumed and thus the amount thereof in the second reactor outlet is too much increased, it becomes difficult to purify the olefin product. In order to increase the consuming amount of methanol and dimethyl ether, the reaction temperature may be increased or the spatial velocity may be brought down. The molar flow rate of the olefin of 4 or more carbon atoms in the second reactor outlet is set to be in the range of 20% or more to less than 70%, with respect to the molar flow rate of the olefin of 4 or more carbon atoms to be fed to the second reactor. The ratio of the molar flow rate is preferably from 25% or more to less than 60% or less. When the consuming amount is too small, it is not preferable because the amount of olefin remaining unreacted increases, and thus the flow rate of the fluid to be recycled into the second reactor undesirably becomes great. On the other hand, when the amount consumed is too much, it is also not preferable because byproducts such as paraffin, aromatic compounds, or the like, are produced, and thus the yield of propylene decreases. In order to adjust the consuming amount of the olefin of 4 or more carbon atoms in the reactor, the reaction temperature or the spatial velocity may be appropriately selected. Here, the flow rates of methanol, dimethyl ether, and olefin of 4 or more carbon atoms which are to be fed to the second reactor can be realized by carrying out a general quantitative analysis such as gas chromatography, on the respective fluids to be fed to the second reactor or a composition of the mixed fluid and then measuring the flow rate of each fluid. The flow rates of methanol, dimethyl ether, and olefin of 4 or more carbon atoms in the second reactor outlet are realized by carrying out a general analysis such as gas chromatography, on the composition of second reactor outlet fluids and then measuring or calculating the flow rate of the second reactor outlet fluids. The "fluid (S) which contains propylene, ethylene, the other olefins, paraffin, aromatic compound, and water" refers to an effluent fluid from the second reactor outlet. As the effluent fluid (S) from the second reactor As the effluent fluid (S) from the second reactor outlet, a mixed gas which includes propylene that is the reaction product, unreacted raw materials, byproducts, and diluents are obtained. The concentration of propylene is generally 5 to 95 wt% of the mixed gas. The unreacted raw materials are generally olefin of 4 or more carbon atoms. The unreacted raw materials may include at least one of methanol and dimethyl ether depending on reaction conditions. However, it is desirable to perform the reaction under conditions where at least one of methanol and dimethyl ether is not to remain. Accordingly, the product and the unreacted raw materials are simply separated from each other. The byproducts may be ethylene, olefin of 4 or more carbon atoms, praraffins, aromatic compounds, and water. Here, the amount of ethylene contained in the effluent fluid (S) in the reactor outlet is preferably 2.0 or less, more preferably less than 1.5, and still more preferably less than 1.0, in a weight ratio with respect to the amount of propylene contained in the same fluid. Above the range, a larger scale of equipment is required for the process, and thus the cost increases. Accordingly, the cost of service for the process is also substantially increased. Within the range, the cost of equipment and service for the process may be considerably reduced. [Explanation on Step (3C)] In the step (3C), the fluid (S) from the step The fluid (S) obtained at the step (2C) is separated by cooling, compressing, distillation, etc. into the hydrocarbon of 2 or less carbon atom-rich fluid (T), the propylene-rich fluid, the hydrocarbon of 4 or more carbon atoms-rich fluid (U), and the water-rich fluid. Here, each of the fluids are not limited to one fluid but may be a plurality of fluids. For example, the hydrocarbon of 2 or less carbon atom-rich fluid (T) may be a single fluid which includes methane, ethylene, and ethane, or may be two fluids which are a methane-rich fluid and an ethylene and ethane-rich fluid. According to necessity, quenching, alkaline cleaning, dehydration, etc. are preferably carried out. When oxygen- containing compounds are included in the reactor outlet gas (S), at least a part of the oxygen-containing compounds are removed by a quenching process. When acidic gases such as carbon dioxide are included in the reactor outlet gas, at least a part of the acidic gases are removed by an alkaline cleaning. Water can be separated by condensation involving compression and cooling. The remaining water content is preferably removed by an absorbent, e.g., molecular sieve. The water removed by condensation and/or absorption may be provided in a process for treating wastewater such as active sludge or the like, or may be used for the water process or the like. When the present process is close to the steam cracking process, the water is preferably used as a steam source of a cracker. In addition, the water may be recycled into the second reactor of the step (2C) so as to be used as a diluent gas. The propylene-rich fluid is desirably refined by a purifying process such as distillation or the like to give propylene with high purity. The purity of propylene is 95% or more, preferably 99% or more, more preferably 99.9% or more. The produced propylene may be used for a raw material of propylene derivatives which are generally produced. For example, the propylene can be used for producing, for example, acrylonitrile by ammoxidation; acrolein, acrylic acid, and acrylate ester, by selective oxidation; oxo alcohols such as normal butanol and 2-ethylhexanol by an oxo reaction; polypropylene by a polymerization of propylene; propylene oxide, propylene glycol, and the like, by selective oxidation of propylene. In addition, acetone can be produced according to the Wacker reaction, and methyl isobutyl ketone can be produced from the acetone. Also from the acetone, acetonecyanhydrin can be produced which can be finally,converted into methyl methacrylate. The propylene can be used to produce isopropyl alcohol by hydration of propylene. Further, phenol, bisphenol A, and polycarbonate resins can be produced with the use of cumene produced by alkylating benzene as a raw material. [Explanation on Step (4C)] In the step (4C), a fluid (P), which is a part of the fluid (T) at the step (3C) is recycled into the first reactor, and the remaining fluid is removed from the process. Here, the fluid (T) may not be introduced to the separation process but just separated into the fluid (P) to be recycled and the fluid to be removed. Also, the fluid (T) may be introduced to the separation process and a fluid of which the concentration of ethylene is increased more than in the fluid (T) is recycled into the first reactor. The removed fluid may be refined to collect available substances such as ethylene or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. Here, the term "part" indicates the range of 10 to 99 wt% of the amount of the fluid (T), preferably 50 to 95 wt% thereof. Below the range, the amount of ethylene a new raw material fed into the first reactor is undesirably increased. Over the range, methane or ethane is accumulated in the first reactor and the recycled fluid, which is not preferable, either. [Explanation on Step (5C)] In the step (5C), a fluid (R), which is a part of the fluid (U) from the step (3C) is recycled into the second reactor, and the remaining fluid is removed from the process. Here, the fluid (U) may not be introduced to the separation process but just separated into the fluid (R) to be recycled and the fluid to be removed. Also, the fluid (U) may be introduced to the separation process and a fluid of which the concentration of butene is increased more than in the fluid (U) is recycled into the second reactor. The removed fluid may be refined to collect available substances such as butene, aromatic compounds, or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. Here, the term "part" generally indicates the range of 10 to 99 wt% of the amount of the fluid (U), preferably 50 to 95 wt% thereof. Below the range, the amount of olefin of 4 or more.carbon atoms fed into the second reactor is decreased, thereby reducing the yield of propylene. Over the range, paraffin is undesirably accumulated in the second reactor and the recycled fluid. [Introduction of Reaction Raw Material] According to the present invention, the fluid which contains olefin of 4 or more carbon atoms may be fed into the second reactor at the step (2C) as a new raw material to produce propylene. There is no particularly limitation on the olefin of 4 or more carbon atoms used in the reaction as a raw material. For example, there can be arbitrarily used olefins having 4 or more carbon atoms, particularly 4 to 10 carbon atoms, which can be produced in accordance with various known methods, such as those produced by catalytic cracking or steam cracking of petroleum feedstock (BB distillate, C4 raffinate-1, C4 raffinate-2, etc.), those produced by carrying out an FT (Fisher-Tropsch) synthesis with the use of a hydrogen/CO gas mixture obtained by gasifying coal as a raw material, those obtained by dehydrogenation or oxidative dehydrogenation of paraffin of 4 or more carbon atoms, those obtained by an MTO reaction, those obtained by dehydrogenation of alcohol, those obtained by hydrogenation of a diene compound of 4 or more carbon atoms, and the like. Here, the olefin of 4 or more carbon atoms provided as a mixture including compounds ' other than olefin of 4 or more carbon atoms which are produced in such production process may be used directly as it is, or the purified olefin may be used. Among them, olefins containing paraffins can be preferably used as a raw material, because the paraffin plays a role as a diluent gas thereby allowing an easy control of the reaction temperature, and also paraffin- containing raw materials are usually easily available with a cheap price. Further preferred are olefin raw materials containing normal butane and/or isobutene. As such preferred raw materials, aforementioned BB distillate, C4 raffinate-1, and C4 raffinate-2, can be mentioned. Here, since the BB distillate contains a large amount of butadiene, it is preferably brought into contact with a hydrogenation catalyst to give a fluid lowered in a butadiene concentration which to be used as a raw material. The supplied amount of a fluid which contains olefin of 4 or more carbon atoms from an outside process is not limited. {Mode for process} Hereinafter, modes for the process according to the present invention will be described with reference to drawings. Fig. 1 illustrates a first embodiment of the process according to the present invention, and Fig. 2 illustrates a second embodiment of the process according to the present invention. In Fig. 1, reference numeral 10 refers to a first reactor, reference numeral 20 refers to a second reactor, and reference numeral 30 refers to a separation and purification system. Reference numerals 101 to 117 indicate pipes, respectively. In Fig. 2, reference numeral 12 refers to a first reactor, reference numeral 22 refers to a second reactor, and reference numeral 32 refers to a separation and purification system. Reference numerals 201 to 217 indicate pipes, respectively. [Explanation on First Embodiment (Fig. 1)3 An ethylene raw material, at least one of methanol and dimethyl ether, and a hydrocarbon of 2 or less carbon atom fluid (F) from a separation and purification system 30 are fed into a first reactor 10 via pipes 101, 102, 103, and 104, respectively. The fluid which is fed into the first reactor via the pipes 101 and/or 103 may include C2- paraffins, for example methane, ethane, or the'like. Also, the raw material fluid fed via the pipe 104 includes the total fluids fed via the pipes 101, 102, and 103, but the fluids may not join before being fed into the first reactor 10. The fluids may be separately fed into the first reactor 10. The raw materials fed into the first reactor 10 are contacted with a catalyst and react in the first reactor 10, thereby giving an effluent fluid (A) from a reactor outlet which contains propylene, hydrocarbon of 4 carbon atoms, ethylene, paraffin, aromatic compounds, and water. Methanol and/or dimethyl ether and a hydrocarbon of 4 or more carbon atoms fluid (G) from the separation and purification system 30 are fed into a second reactor 20 via the pipes 106, 107, and 109, respectively. Also, a olefin of 4 or more carbon atoms raw material may be fed into the second reactor 20 though the pipes 108 and 109. A fluid fed into the second reactor 20 via the pipes 108 and/or 107 may include C4+ paraffins, for example normal butane, isobutane, and the like. A fluid fed into the second reactor 20 via the pipe 109 may include butadiene, aromatic compounds, and water. Also, the raw material fluid introduced via the pipe 109 may include the total fluids fed via the pipes 106 and 107, the fluid fed via the pipe 108 as necessary, but the fluids may not join before being fed into the second reactor 20. The fluids may be separately fed into the second reactor 20. The raw materials fed into the second reactor 20 are contacted with a catalyst and react in the second reactor 20, thereby giving an effluent fluid (B) from a reactor outlet which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compounds, and water. The fluid (A) from the outlet of the first reactor 10 and the fluid (B) from the outlet of the second reactor 20 join via the pipe 105 and the pipe 110, respectively, thereby giving a fluid (C). The fluid (C) is provided to the separation and purification system 30 via a pipe 111 for cooling, compressing, and distillation, and separated into a hydrocarbon of 2 or less carbon atom-rich fluid (D), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (E), and a water-rich fluid. The respective fluids are removed via pipes 112, 113, 114, and 115. Here, each of the fluids represents one or more, fluid. For example, the hydrocarbon of 2 or less carbon atom-rich fluid (D) may be a single fluid which includes methane, ethylene, and ethane, or may be two fluids which are a methane-rich fluid and an ethylene and ethane-rich fluid. A part (F) of the hydrocarbon of 2 or less carbon atom-rich fluid (D) is recycled into the first reactor 10 via the pipe 103, and the remaining fluid is removed from the process via the pipe 116. Here, the fluid (D) may be separated and purified by distillation or the like to thereby increase the concentration of ethylene and recycled into the first reactor 10. The removed fluid via the pipe 116 may be refined to collect available substances such as ethylene or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. The propylene-rich fluid obtained via the pipe 113 is separated and purified by distillation or the like, thereby desirably giving propylene with high purity. The water obtained via the pipe 115 may be provided to a waste water treatment process to treat active sludge or the like, or used for the process. If the process is close to a steam cracking process, the water is preferably used as a steam source of a cracker. In addition, the water is recycled into the first reactor 10 and/or the second reactor 20 and then used as a diluent gas. A part (G) of the hydrocarbon of 4 or more carbon atoms-rich fluid (E) is recycled into the second reactor 20 via the pipe 107, and the remaining fluid is removed from the process via the pipe 117. Here, the fluid (E) may be separated and purified by distillation or the like to thereby increase the concentration of butene and recycled into the second reactor 20. The removed fluid via the pipe 117 may be refined to collect available substances such as butene, aromatic compound, or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. [Explanation on Second Embodiment (Fig. 2)] An ethylene raw material, at least one of methanol and dimethyl ether, and a hydrocarbon of 2 or less carbon atom fluid (L) from a separation and purification system 32 are fed into a first reactor 12 via pipes 201, 202, 203, and 204, respectively. The fluid which is fed into the first reactor via the pipes 201 and/or 203 may include C2- paraffins, for example methane, ethane, and the like. Also, the raw material fluid fed via the pipe 204 includes the total fluids fed via the pipes 201, 202, and 203, but the fluids may not join before being fed into the first reactor 12. The fluids may be separately fed into the first reactor 12. The raw materials fed into the first reactor 12 are contacted with a catalyst and react in the first reactor 12, thereby giving an effluent fluid (A) from a reactor outlet which contains propylene, hydrocarbon of 4 carbon atoms, ethylene, paraffin, aromatic compounds, and water. The fluid (A) from the outlet of the first reactor 12, at least one of methanol and dimethyl ether, and a hydrocarbon of 4 or more carbon atoms fluid (M) from the separation and purification system 30 are fed into a second reactor 22 via the pipes 205, 206, 207, and 209, respectively. Also, a olefin of 4 or more carbon atoms raw material may be fed into the second reactor 22 though the pipes 208 and 209. A fluid fed into the second reactor 22 via the pipes 208 and/or 207 may include C4+ paraffins, for example normal butane, isobutane, and the like. A fluid fed into the second reactor 22 via the pipe 209 may include butadiene, aromatic compounds, and water. Also, the raw material fluid introduced via the pipe 209 may include the total fluids fed via the pipes 205, 206 and 207, including the fluid fed via the pipe 208 as necessary, but the fluids may not join before being fed into the second reactor 22. The fluids may be separately fed into the second reactor 22. The raw materials fed into the second reactor 22 are contacted with a catalyst and react in the second reactor 22, thereby giving an effluent fluid (I) from a reactor outlet which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compounds, and water. The effluent fluid (I) from the outlet of the second reactor 22 is provided to the separation and purification system 32 via a pipe 210 for cooling, compressing, and distillation, and separated into a hydrocarbon of 2 or less carbon atom-rich fluid (J), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (K), and a water-rich fluid. The respective fluids are removed via pipes 212, 213, 214, and 215. Here, each of the fluids represents one or more fluid. For example, the hydrocarbon of 2 or less carbon atom-rich fluid (J) may be a single fluid which includes methane, ethylene, and ethane, or may be two fluids which are a methane-rich fluid and an ethylene and ethane-rich fluid. A part (L) of the hydrocarbon of 2 or less carbon atom-rich fluid (J) is recycled into the first reactor 12 via the pipe 203, and the remaining fluid is removed from the process via the pipe 216. Here, the fluid (J) may be separated and purified by distillation or the like to thereby increase the concentration of ethylene and recycled into the first reactor 12. The removed fluid via the pipe 216 may be refined to collect available substances such as ethylene or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. ^ The propylene-rich fluid obtained via the pipe 213 is separated and purified by distillation or the like, thereby desirably giving propylene with high purity. The water obtained via the pipe 215 may be provided to a waste water treatment process to treat active sludge or the like, or used for the process. If the process is close to a steam cracking process, the water is preferably used as a steam source of a cracker. In addition, the water is recycled into the first reactor 12 and/or the second reactor 22 and then used as a diluent gas. A part (M) of the hydrocarbon of 4 or more carbon atoms-rich fluid (K) is recycled into the second reactor 22 via the pipe 207, and the remaining fluid is.removed from the process via the pipe 217. Here, the fluid (K) may be separated and purified by distillation or the like to thereby increase the concentration of butene and recycled into the second reactor 22. The removed fluid via the pipe 217 may be refined to collect available substances such as butene, aromatic compound, or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. [Explanation on Third Embodiment (Fig. 3)] Hereinafter, an embodiment of the process according to the present invention will be described with reference to drawing. Fig. 3 illustrates an embodiment of the process according to the present invention. [0069] In Fig. 3, reference numeral 13 refers to a first reactor, reference numeral 23 refers to a second reactor, and reference numeral 33 refers to a separation and purification system. Reference numerals 301 to 315 indicate pipes, respectively. An ethylene raw material and a hydrocarbon of 2 or less carbon atom-rich fluid (P) from the separation and purification system 33 are fed into a first reactor 13 via pipes 301, 302 and 303. The fluid which is fed into the reactor 13 via the pipes 301 and/or 302 may include C2- paraffins, for example methane, ethane, and the like. Also, the raw material fluid fed via the pipe 303 includes the total fluids fed via the pipes 301 and 302, but the fluids may not join before being fed into the first reactor 13. The fluids may be separately fed the first reactor 13. The raw materials fed into the first reactor 13 are contacted with an ethylene dimerization catalyst and react in the reactor 13, thereby giving an effluent fluid (Q) from a reactor outlet which contains hydrocarbon of 4 carbon atoms. In Fig. 3, the first reactor 13 is provided as a liquid reactor, but a gas reactor is also available. In the case of a liquid reactor, a step of removing a catalyst is performed after a reaction. According to Fig. 3, the whole fluid (Q) is fed into the second reactor 23 via pipes 304 and 308. As necessary, however, a part of the fluid (Q) is removed to be used for another purpose. The fluid (Q) from the first reactor outlet, a hydrocarbon of 4 or more carbon atoms-rich fluid (R) from the separation and purification system 33, and at least one of methanol and dimethyl ether, are fed into a second reactor 23 via the pipes 304, 306, 307, and 308, respectively. Also, a olefin of 4 or more carbon atoms raw material may be fed into the second reactor 23 though the pipes 305 and 308. A fluid fed into the second reactor 23 via the pipes 306 and/or 305 may include C4+ paraffins, for example normal butane, isobutane, and the like. A fluid fed into the second reactor 23 via the pipe 308 may include butadiene, aromatic compounds, and water. Also, the raw material fluid introduced via the pipe 308 may include the total fluids fed via the pipes 304, 306 and 307, including the fluid fed via the pipe 305 as necessary, but the fluids may not join before being fed into the second reactor 23. The fluids may be separately fed into the second reactor 23. The raw materials fed into the second reactor 23 are contacted with a propylene production catalyst and react in the second reactor 23, thereby giving an effluent fluid (S) from a reactor outlet which contains propylene, ethylene, other olefins, paraffin, aromatic compounds, and water. The effluent fluid (S) from the outlet of the second reactor 23 is provided to the separation and purification system 33 for cooling, compressing, and distillation, and separated into a hydrocarbon of 2 or less carbon atom-rich fluid (T), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (U), and a water-rich fluid. The respective fluids are removed via pipes 310, 311, 312, and 313. Here r each of the fluids represents one or more fluid. For example, the hydrocarbon of 2 or less carbon atom-rich fluid (T) may be a single fluid which includes methane, ethylene, and ethane, or may be two fluids which are a methane-rich fluid and an ethylene and ethane-rich fluid. A part (P) of the hydrocarbon of 2 or less carbon atom-rich fluid (T) is recycled into the first reactor 13 via the pipe 302, and the remaining fluid is removed from the process via the pipe 314. Here, the fluid (T) may be separated and purified by distillation or the like to thereby increase the concentration of ethylene and recycled into the first reactor 13. The removed fluid via the pipe 314 may be refined to collect available substances such as ethylene or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. The propylene-rich fluid obtained via the pipe 311 is separated and purified by distillation or the like, thereby desirably giving propylene with high purity. The water obtained via the pipe 313 may be provided to a waste water treatment process to treat active sludge or the like, or used for the process. If the process is close to a steam cracking process, the water is preferably used as a steam source of a cracker. I n addition, the water is recycled into the second reactor 23 and then used as a diluent gas. A part (R) of the hydrocarbon of 4 or more carbon atoms-rich fluid (U) is recycled into the second reactor via the pipe 306, and the remaining fluid is removed from the process via the pipe 315. Here, the fluid (U) may be separated and purified by distillation or the like to thereby increase the concentration of butene and recycled into the second reactor 23. The removed fluid via the pipe 315 may be refined to collect available substances such as butene, aromatic compound, or the like, and used as a fuel. Further, the removed fluid may be used as a raw material for steam cracking. [EXAMPLES] Hereinafter, the present invention will be described in detail with reference to examples, but is not limited by the following examples. [Preparation of Catalyst] Catalysts used for the following Examples and Comparative Example were prepared in the following manner. 2 6.6 g of bromide tetra-n-propyl ammonium bromide (TPABr) and 4.8 g of sodium hydroxide were sequentially dissolved in 280 g of water. Next, the mixed solution of 75 g of colloidal silica (Si02 = 40 wt%, Al 2.0 g of the Na-type alumino silicate was suspended in 40 ml of a 1M aqueous ammonium nitrate solution, and the resultant solution was stirred at 80°C for 2 hours. The solid component was separated from the solution after the treatment by filtration under absorption, resuspended in 40 ml of a 1M aqueous ammonium nitrate solution after being thoroughly washed with water, and the resultant solution was stirred at 80°C for 2 hours. The solid component was separated from the solution after the treatment by filtration under absorption, and dried at 100°C for 24 hours after being thoroughly washed with water. The dried catalyst was burned at 550°C for 4 hours under a ventilation condition to obtain H-type alumino silicate. It is confirmed that the catalyst is an MFI type in zeolite structure by X-ray diffraction (XRD). According to a chemical analysis, the composition of the catalyst was Si02/Al203 = 1100 in a molar ratio. [Preparation of Propylene] Hereinafter, Examples and Comparative Example of preparation of propylene using the catalyst will be shown. Referring to Fig. 2, the flow rate (weight/hour) of the ethylene raw material (pipe 201 in the figure) was given as 100 and the flow rates (weight/hour) of the methanol raw materials to be fed from the pipe 202 and pipe 206 were each given as 225 (250 in total), to prepare the simulated gas (including ethylene and methanol) of the first reactor (12) inlet (pipe 204), and further the simulated gas (including ethylene, methanol, and butene) of a fluid (total fluid combined with fluids in pipe 206 and pipe 207) freshly introduced in the second reactor (22) was prepared, so as to carry out a production of propylene in the two reactors arranged in series as illustrated in Fig. 3. The catalyst was filled in the both reactors and the reaction was carried out under a normal pressure, but the reaction temperature in the first reactor outlet was 4 50°C and the reaction temperature in the second reactor outlet was 550°C. A separation step (32) of an effluent gas from the second reactor was carried out with the use of an Aspen Plus simulator, and the flow rates of fluids containing recycling gas were determined. On the basis of the obtained flow rate of the recycling gas (pipes 203 and 207), the gas composition of fluids (pipes 206 and 207 in total) freshly introducing into the first reactor inlet and the second reactor (22} was calculated, and the reaction was again carried out using the re-prepared simulated gas. This procedure was repeated 10 times, thereby finally determining the flow rates of each fluid for the process in Fig. 2 by experiment and simulation. As a result, the flow rate (weight/hour) of ethylene in the first reactor inlet (pipe 204) was 244, the flow rate (weight/hour) of ethylene in the first reactor outlet (pipe 205) was 144, and the flow rate (weight/hour) of olefin of 4 or more carbon atoms of the fluid (pipe 207) recycled into the second reactor was 381. The conversion ratio of ethylene in the first reactor was 41%. Further, the flow rate (weight/hour) of propylene in the second reactor outlet (pipe 210: fluid O) was 185, the flow rate (weight/hour) of ethylene was 156, and the flow rate of olefin of 4 or more carbon atoms was 385. The amount of ethylene contained in the fluid (I) was 0.84 in a weight ratio with respect to the amount of propylene. Referring to Fig. 3, the flow rate (weight/hour) of the ethylene raw material (pipe 301 in the figure) was given as 100 and the flow rates (weight/hour) of the methanol raw materials (pipe 307 in the figure) was given as 250, to prepare the simulated gas (including ethylene, methanol, and butene) of the second reactor (23) inlet (pipe 308), and carry out a production of propylene with the use of the catalyst under conditions of reactor outlet temperature: 550°C and normal pressure. A separation step (33) of an effluent gas from the second reactor was carried out with the use of an Aspen Plus simulator, and the flow rates of fluids containing recycling gas were determined, it was assumed that the conversion ratio of ethylene in the first reactor performing a dimerization reaction of ethylene is 90%. On the basis of the obtained flow rate of the recycling gas (pipes 302 and 306), the gas composition in the second reactor inlet was calculated, and the reaction was again carried out using the re-prepared simulated gas. This procedure was repeated 10 times, thereby finally determining the flow rates of each fluid for the process in Fig. 3 by experiment and simulation. As a result, the flow rate (weight/hour) of ethylene in the second reactor inlet was 18, the flow rate (weight/hour) of olefin of 4 or more carbon atoms was 556, the flow rate (weight/hour) of propylene in the second reactor outlet (pipe 309: fluid D) was 189, the flow rate (weight/hour) of ethylene was 83, and the flow rate of olefin of 4 or more carbon atoms was 4 04. The amount of ethylene contained in the fluid S was 0.44 in a weight ratio with respect to the amount of propylene. Referring to Fig. 4, the flow rate (weight/hour) of the ethylene raw material (pipe 401 in the figure) was given as 100 and the flow rates (weight/hour) of the methanol raw materials (pipe 402 in the figure) was given as 250, to prepare the simulated gas (including ethylene, methanol, and butene) of the reactor (70) inlet (pipe 404), and carry out a production of propylene with the use of the catalyst under conditions of reactor outlet temperature: 550°C and normal pressure. A separation step (80) of an effluent gas from the reactor was carried out with the use of an Aspen Plus simulator, and the flow rates of fluids containing recycling gas were determined. On the basis of the obtained flow rate of the recycling gas (pipes 403 and 411), the gas composition in the reactor inlet was calculated, and the reaction was again carried out using the re-prepared simulated gas. This procedure was repeated 10 times, thereby finally determining the flow rates of each fluid for the process in Fig. 4 by experiment and simulation. As a result, the flow rate (weight/hour) of ethylene in the reactor inlet was 589, the flow rate (weight/hour) of olefin of 4 or more carbon atoms was 321, the flow rate (weight/hour) of propylene in the reactor outlet (pipe 405) was 171, the flow rate (weight/hour) of ethylene was 504, and the flow rate of olefin of 4 or more carbon atoms was 328. The amount of ethylene contained in the reactor outlet fluid was 2.95 in a weight ratio with respect to the amount of propylene, which was the value bigger than those in Example 1 and Example 2. This application is based on Japanese Patent Application filed on September 26, 2006 {Application No. 2006-260809) and Japanese Patent Application filed on September 26, 2006 (Application No. 2006-260810), the contents thereof being herein incorporated by reference. INDUSTRIAL APPLICABILITY The present invention provides a novel process for producing propylene using ethylene and at least one of methanol and dimethyl ether as raw material, in which the amount of unreacted ethylene to be recycled is small and the cost for equipment and service is low. WE CLAIM : [Claim 1] A process for producing propylene using ethylene, or ethylene and at least one of methanol and dimethyl ether as a raw material, wherein the raw material is reacted in the presence of a first catalyst in a first reactor to obtain a fluid (X) including olefin of 4 or more carbon atoms, and at least part of the fluid (X) is reacted with at least one of methanol and dimethyl ether in the presence of a second catalyst in a second reactor to obtain a fluid which includes propylene. [Claim 2] A process for producing propylene using ethylene and at least one of methanol and dimethyl ether as a raw material, wherein the ethylene and at least one of methanol and dimethyl ether are reacted in the presence of a first catalyst in a first reactor to obtain a fluid (A) which includes propylene and olefin of 4 or more carbon atoms, and at least part of olefin of 4 or more carbon atoms contained in the fluid (A) is reacted with at least one of methanol and dimethyl ether in the presence of a second catalyst in a second reactor to obtain propylene. [Claim 3] The process for producing propylene according to Claim 2, comprising the following steps (1A), (2A), (3A), (4A), and (5A): step(lA): feeding an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (F) recycled from a step (4A) to a first reactor; and contacting the raw materials with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water, step (2A): feeding at least one of methanol and dimethyl ether as a raw material and a fluid (G) recycled from a step (5A) to a second reactor; and contacting the raw materials with a second catalyst, thereby obtaining a fluid (B) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water, step (3A): separating a fluid (C) where the fluid (A) and the fluid (B) are mixed into a hydrocarbon of 2 or less carbon atom-rich fluid (D), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (E), and a water-rich fluid, step (4A): recycling a part fluid (F) of the fluid (D) to the first reactor and removing the remaining fluid from the process, and step (5A) : recycling a part fluid (G) of the fluid (E) to the second reactor and removing the remaining fluid from the process. [Claim 4] The process for producing propylene according to Claim 3, wherein the amount of ethylene contained in the fluid {C) is less than 2.0 in a weight ratio, with respect to the amount of propylene contained in the fluid (C). [Claim 5] The process for producing propylene according to Claim 2, comprising the following steps (IB), (2B) , (3B), (4B), and (5B): step(lB): feeding an ethylene as a raw material, at least one of methanol and dimethyl ether as a raw material, and a fluid (L) recycled from a step (4B) to a first reactor; and contacting the raw materials with a first catalyst, thereby obtaining a fluid (A) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and a fluid containing water, step (2B): feeding the fluid (A), at least one of methanol and dimethyl ether as a raw material, and a fluid (M) recycled from a step (5B) to a second reactor; and contacting the raw materials with a second catalyst, thereby obtaining a fluid (I) which contains propylene, olefin of 4 or more carbon atoms, ethylene, paraffin, aromatic compound, and water, step (3B): separating the fluid (I) into a hydrocarbon of 2 or less carbon atom-rich fluid (J), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (K), and a water-rich fluid, step (4B): recycling a part fluid (L) of the fluid (J) to the first reactor and removing the remaining fluid from the process, and step (5B): recycling a part fluid (M) of the fluid The process for producing propylene according to any one of Claims 1 to 6, wherein a fluid which contains olefin of 4 or more carbon atoms is fed into the second reactor out of the process. [Claim 8] The process for producing propylene according to any one of Claims 1 to 7, wherein an outlet of the first reactor is lower in temperature than an outlet of the second reactor. [Claim 9] The process for producing propylene according to any one of Claims 1 to 8, wherein the conversion ratio of ethylene in the first reactor which is calculated by the following equation is 30% or more: Conversion ratio of ethylene {%) = {(flow rate of ethylene in "inlet of first reactor - flow rate of ethylene in outlet of first reactor)/ flow rate of ethylene in inlet of first reactor} x 100. [Claim 10] A process for producing propylene using ethylene and at least one of methanol and dimethyl ether as a raw material, comprising a step of reacting at least one of methanol and dimethyl ether and hydrocarbon of 4 carbon atoms obtained by a dimerization reaction of ethylene. [Claim 11] The process for producing propylene according to Claim 10, comprising the following steps (1C), (2C), (3C), (4C), and (5C): step(lC): feeding an ethylene as a raw material, and a fluid (P) recycled from a step (4C) to a first reactor; and contacting the raw materials with an ethylene dimerization catalyst, thereby obtaining a fluid (Q) which contains hydrocarbon of 4 carbon atoms, step (2C): feeding the fluid (Q) from the step (1C), a fluid (R) recycled from a step (5C), and at least one of methanol and dimethyl ether to a second reactor; and contacting the materials with a propylene production catalyst, thereby obtaining a fluid (S) which contains propylene, ethylene, the other olefin, paraffin, aromatic compound, and water, step (3C): separating the fluid (S) from the step (2C) into a hydrocarbon of 2 or less carbon atom-rich fluid (T), a propylene-rich fluid, a hydrocarbon of 4 or more carbon atoms-rich fluid (U), and a water-rich fluid, step (4C): recycling a part fluid (P) of the fluid (T) from the step (3C) to the first reactor and removing the remaining fluid from the process, and step (5C): recycling a part fluid (R) of the fluid (U) from the step (3C) to the second reactor and removing the remaining fluid from the process. [Claim 12] The process for producing propylene according to Claim 11, wherein a part of the fluid (Q) is not fed into the second reactor in the step (2C) but removed outside the process. [Claim 13] The process for producing propylene according to Claim 11 or 12, wherein a fluid which contains olefin of 4 or more carbon atoms is fed into the second reactor out of the process. [Claim 14] The process for producing propylene according to any one of Claims 10 to 13, wherein the amount of ethylene contained in the fluid (S) is less than 2.0 in a weight ratio, with respect to the amount of propylene contained in the fluid (S). |
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602-MUMNP-2009-ABSTRACT(25-3-2009).pdf
602-MUMNP-2009-CLAIMS(25-3-2009).pdf
602-MUMNP-2009-CLAIMS(AMENDED)-(3-6-2013).pdf
602-MUMNP-2009-CLAIMS(MARKED COPY)-(3-6-2013).pdf
602-MUMNP-2009-CORRESPONDENCE(10-5-2013).pdf
602-MUMNP-2009-CORRESPONDENCE(18-4-2013).pdf
602-MUMNP-2009-CORRESPONDENCE(23-1-2013).pdf
602-MUMNP-2009-CORRESPONDENCE(25-9-2009).pdf
602-MUMNP-2009-CORRESPONDENCE(28-8-2012).pdf
602-MUMNP-2009-CORRESPONDENCE(9-9-2010).pdf
602-MUMNP-2009-DESCRIPTION(COMPLETE)-(25-3-2009).pdf
602-MUMNP-2009-DRAWING(25-3-2009).pdf
602-MUMNP-2009-ENGLISH TRANSLATION(23-1-2013).pdf
602-MUMNP-2009-FORM 1(24-9-2009).pdf
602-MUMNP-2009-FORM 1(25-3-2009).pdf
602-MUMNP-2009-FORM 1(28-8-2012).pdf
602-MUMNP-2009-FORM 13(25-9-2009).pdf
602-MUMNP-2009-FORM 13(28-8-2012).pdf
602-MUMNP-2009-FORM 18(9-9-2010).pdf
602-MUMNP-2009-FORM 2(COMPLETE)-(25-3-2009).pdf
602-MUMNP-2009-FORM 2(TITLE PAGE)-(25-3-2009).pdf
602-MUMNP-2009-FORM 26(25-3-2009).pdf
602-MUMNP-2009-FORM 3(18-4-2013).pdf
602-MUMNP-2009-FORM 3(24-9-2009).pdf
602-MUMNP-2009-FORM 3(25-3-2009).pdf
602-MUMNP-2009-FORM 5(25-3-2009).pdf
602-MUMNP-2009-OFFICE ACTION(10-5-2013).pdf
602-MUMNP-2009-OTHER DOCUMENT(18-4-2013).pdf
602-MUMNP-2009-REPLY TO EXAMINATION REPORT(3-6-2013).pdf
602-MUMNP-2009-WO INTERNATIONAL PUBLICATION REPORT A1(9-9-2010).pdf
| Patent Number | 257553 | ||||||||||||||||||
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| Indian Patent Application Number | 602/MUMNP/2009 | ||||||||||||||||||
| PG Journal Number | 42/2013 | ||||||||||||||||||
| Publication Date | 18-Oct-2013 | ||||||||||||||||||
| Grant Date | 15-Oct-2013 | ||||||||||||||||||
| Date of Filing | 26-Mar-2009 | ||||||||||||||||||
| Name of Patentee | MITSUBISHI CHEMICAL CORPORATION | ||||||||||||||||||
| Applicant Address | 14-1 SHIBA 4-CHOME MINATO-KU TOKYO 108-0014 JAPAN | ||||||||||||||||||
Inventors:
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| PCT International Classification Number | C07C 4/02 | ||||||||||||||||||
| PCT International Application Number | PCT/JP2007/068572 | ||||||||||||||||||
| PCT International Filing date | 2007-09-25 | ||||||||||||||||||
PCT Conventions:
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