Title of Invention

A METHOD OF OPERATING AN EMULSIFIED FUEL EVAPORATOR SYSTEM AND AN EMULSIFIED FUEL EVAPORATOR SYSTEM

Abstract

The present invention relates to a method of operating an emulsified fuel evaporator system comprising preheating emulsified fuel in a preheater so as to obtain a preheated emulsified fuel; regulating a temperature of the preheated emulsified fuel such that the temperature of the preheated emulsified fuel is maintained constant heating the preheated emulsified finale in an evaporator so as to obtain a heated emulsified fuel; regulating an evaporator differential temperature such that the evaporator differential temperature is maintained constant; separating the heated emulsified fuel in a separator so as to obtain a water portion and a heavy oil portion, the water portion comprising a preheating medium channeled to the preheater for said preheating of the emulsified field; regulating a pressure of the preheating medium such that the pressure of the preheating medium is maintained constant; and transmitting sound waves through the separator.

Full Text

HEAVY OIL EMULSIFIED FUEL EVAPORATOR SYSTEM AND OPERATION METHOD THEREOF BACKGROUND OF THE INVENTION: Field of the Invention: The present invention relates to an evaporator system for separation of water content in a heavy oil emulsified fuel by way of heating and an operation method thereof. Description of the Prior Art: As heavy oil is of a high consistency nature, in order to make its handling of transportation and storage easier, heavy oil fuel is added in advance with an appropriate amount of water and surface active agent so as to form what is called a heavy oil emulsified fuel, when this heavy oil emulsified fuel is to be burned in a combustion furnace of a boiler etc. it is desirable to remove water content from the heavy oil emulsified fuel for combustion efficiency. A prior art evaporator system for separation of water content in the heavy oil emulsified fuel is shown in Fig. 7 and description will be made thereon. In Fig. 7, numeral 11 designates a tank, in which an emulsified fuel 11a is stored. Numeral 12 designates a pump, numeral 13 designates a preheater, numeral 14 designates an evaporator, numeral 15 designates a separator, numeral 16 designates a heating steam supply equipment and numeral 17 designates a pump. In the evaporator system of Fig. 7 having such equipment and machinery, the emulsified fuel 11a, containing water, in the tank 11 is fed into the preheater 13 via the pump 12 and a piping lib. A heat exchanger tube 13a is provided within the preheater 13 for flow of heating water or steam, after separated, as a preheating source medium which is described later, and the emulsified fuel 11a is filled surrounding the heat exchanger tube 13a. It is to be noted that the preheating source medium and the emulsified fuel 11a may be flown either on inside or on outside of the heat exchanger tube 13a. The emulsified fuel 11a outside of the heat exclianger tube 13a is preheated to a certain temperature through heat exchange with the preheating source medium and is sent to the evaporator 14 via a piping 13b. Within the evaporator 14 provided are a plurality of generating tubes 14a, 14b, 14c, for flow of the preheated emulsified fuel 11a. On the other hand, the emulsified fuel 11a is heated by a heating source medium surrounding the generating tubes 14a, 14b, 14c, the heating source medium being a heating steam, for example, which is supplied from the heating steam supply equipment 16 via a piping 16a, and the heating source medium of which temperature has been lowered is discharged through a piping 16b- Thus, the emulsified fuel 11a within the generating tubes 14a, 14b, 14c is boiled to be evaporated and is then sent to the separator 15 via a piping 14d. The emulsified fuel 11a fed into the separator 15 is separated into water content (steam) and heavy oil fuel. The water content separated from the emulsified fuel 11a at the separator 15 is sent to the preheater 13 via a piping 15a in a state of heating water or steam to be used as a preheating source which flows in said heat exchanger tube 13a of the preheater 13 and, after its temperature has been lowered, is discharged out of the system via a piping 15b. It is to be noted that a surplus water remaining after the separated water has been taken for said preheating source is extracted outside of the system via a valve 15c and a piping 15d to be used for an atomizing steam etc. Also, the heavy oil fuel of which water content has been separated at the separator 15 is taken out of the system via a piping 15e and a pump 17 to be burned in a combustion system (a boiler, for example) having main equipments, such as a tank, a burner, etc. which are not shown in the figure. In order to make effective use of heat input amount of the heating source medium fed into the evaporator 14, a heat regeneration type is used in which the water content separated from the emulsified fuel at the separator 15 is introduced into the preheater 13 as the preheating source medium so that its heat source is made use of repeatedly, and a design of construction consisting of the preheater 13, the evaporator 14, etc. having such a heating area as is compact to the extent possible is employed. In the prior art evaporator system as described above, it is essential to operate it so as to obtain such a high efficiency water separation as brings on a maximum thermal efficiency, a best compact-sized design of equipment and machinery and an always constant predetermined value of water content in the heavy oil emulsified fuel which is obtained after separation. In the mentioned combustion system (boiler etc.) for burning the separated heavy oil fuel, however, amount of use of the heavy oil fuel used therein is not always constant but varies unavoidably corresponding to load change in the boiler etc. For example, if flow rate of the emulsified fuel is increased from a certain flow rate, because the system is of a closed loop, amount of the preheating source medium from the piping 15a does not increase rapidly resulting in lowering of outlet temperature of the preheater and change of the operation conditions. Thus, when the amount of the emulsified fuel {hereinafter called a "load" ) sent to the preheater 13 from the tank 11 changes, because the system employs a heat regeneration type, there occurs a delay in delivery and receipt of heat and temperature in each portion changes, which results in that the water content in the emulsified fuel obtained after separation does not become constant, and as one countermeasure therefor, there is given unavoidably a considerable allowance in the design of heating area in the heat exchanger portion of each component equipment and machinery. On the other hand, there is mixed a small amount of light oil content in the water content separated at the separator 15 and the preheating source medium in which this light oil content is mixed is used for heat exchange at the preheater 13. When this preheating source medium is discharged in a state of steam (gas) from the preheater 13, the light oil content mixed therein in a state of vapor is condensed soon together with the water content so that the oil content is suspended in the water. The oil content once suspended in the water being hardly separated or removed by a general oil content treatment equipment, draining thereof into rivers and the like becomes impermissible and there occurs an obstacle in the operation of the evaporator system. Further, if there occurs a pressure reduction action in the separator 15, the water content in the emulsified fuel which is heated to a high temperature at the evaporator 14 flashes (evaporizes) rapidly and gets out hardly of the surrounding high consistency heavy oil fuel resulting in a state of bubbles in which the emulsified fuel surrounds the steam gas. As the result, volume of the fuel increases rapidly to become full in the separator 15 or to cause an overflow in Further, it is an object of the present invention to provide a heavy oil emulsified fuel evaporator system having a separator into which the heavy oil emulsified fuel heated at the evaporator is led for separation of water content, said separator being able to prevent the water content in the emulsified fuel from flashing therein and being discharged out of the system. In order to attain said object to enable a predetermined water content separation constantly, the present invention provides an operation method of a heavy oil emulsified fuel evaporator system, characterized in that outlet temperature of a preheater or inlet temperature of an evaporator is controlled constant, pressure in a preheating source medium supply piping for leading a preheating source medium into said preheater is controlled constant and temperature difference of an outlet temperature relative to the inlet temperature of said evaporator is controlled constant. In case of load change, flow rate of the emulsified fuel flowing into the preheater is increased or decreased and the temperature, pressure and flow rate at each of the above-mentioned portions change corresponding thereto, but by employing the above operation control method of the present invention, a rapid change in the inlet temperature and outlet temperature of the evaporator and the pressure of the preheating source medium in a piping is avoided so as to be suppressed into a slow change. As the result, change in the water content remaining in the heavy oil fuel after separated of its water content is avoided, and even in the case of load change, the operation to control the water content to a substantially constant and stable level becomes possible in the entire evaporator system as well. In the evaporator system to which said operation method is applied, it is desirable to employ a construction for storing the emulsified fuel of an increasable amount, as preheated, in the preheater or between the preheater and the evaporator. With this construction wherein the constant temperature emulsified fuel of the increasable amount it stored in advance, even in the case of load change, the emulsified fuel of a predetermined temperature can be supplied into the inlet of the evaporator and the water content in the heavy oil fuel separated thereby can be maintained to a predetermined value constantly. Also, in order to attain said object to discharge no light oil content together with eater content, the present invention provides a heavy oil emulsified fuel evaporator system characterized in that a preheater for preheating the heavy oil emulsified fuel of which water content is to be separated is constructed of a first heat exchanger using steam as the preheating source medium and having a level switch and a second heat exchanger communicating with the first exchanger Also, in order to attain said object to prevent the water content in the emulsified fuel from flashing in the separator and being discharged out of the system, the present invention provides a heavy oil fuel emulsified fuel evaporator system characterized in that a separator into which the heavy oil emulsified fuel, after heated, is led is provided with a plurality of opening portions in an upward and downward direction in its side wall and a transmitter for transmitting a sound wave and a receiver for receiving said sound wave are provided to said opening portions. By employing such a separator as so constructed, bubble generation phenomena in the separator can be detected in advance continuously, so that discharge of the heavy oil fuel out of the system due to overflow can be prevented. Also, by a spreading energy of the sound wave, defoaming effect can be expected. Accordingly the present invention provides a method of operating an emulsified fuel evaporator system comprising preheating emulsified fuel in a preheater so as to obtain a preheated emulsified fiiel; regulating a temperature of the preheated emulsified ftiel such that the temperature of the preheated emulsified fuel is maintained constant; heating the preheated emulsified fiiel in an evaporator so as to obtain a heated emulsified fuel; regulating an evaporator differential temperature such that the evaporator differential temperature is maintained constant; separating the heated emulsified fuel in a separator so as to obtain a water portion and a heavy oil portion, the water portion comprising a preheating medium channeled to the preheater for said preheating of the emulsified fuel; regulating a pressure of the preheating medium such that the pressure of the preheating medium is maintained constant; and transmitting sound waves through the separator. The present invention also provides a system comprising; a preheater having a first heat exchanger using steam as a preheating medium and a second heat exchanger using hot water as a preheating medium, said second heat exchanger communicating with said first heat exchanger through a flow control valve, a level switch being provided at said first heat exchanger for detecting a preheating medium level in said first heat exchanger, said level switch being connected to said flow control valve so as to operate said flow control valve based on the detected preheating medium level, wherein the emulsified fuel is preheated in said preheater by entering said second heat exchanger and flowing fi^m said second heat exchanger to said first heat exchanger; an evaporator communicating with said preheater such that preheated emulsified fuel flows fi-om said preheater to said evaporator; a separator communicating with said evaporator such that heated emulsified fuel flows fi*om said evaporator to said separator, said separator being capable of separating the heated emulsified fuel into a water portion and a heavy oil portion, said separator communicating with said preheater so that the water portion comprises the preheating medium used in said preheater; and a sound wave component for transmitting sound waves through said separator. The invention will now be described more in detail with reference to embodiments given by way of example and shown in tiie accompanying drawings, in which; Figure 1 is a diagrammatic view showing a construction of an evaporator system according to a fu-st embodiment of the present invention. Figure 2 is a graph showing a relationship between temperature difference in evaporator inlet and outlet temperatures and water content in a heavy oil emulsified fuel after separation of its water content. Fig. 3 is a diagrammatic view showing a construction of an evaporator system according to a second embodiment of the present invention. Fig. 4 is a diagrammatic view showing a construction of an evaporator system according to a third embodiment of the present invention. Fig. 5 is an explanatory view showing a construction of a separator to be used for an evaporator system according to a fourth embodiment of the present invention. Fig. 6 is a cross sectional view taken along line A-A of Fig 5. Fig. 7 is a diagrammatic view showing a construction of a prior art evaporator system. DESCRIPTION OF THE PREFERRED EMBODIMENTS: Herebelow, description will be made concretely on a heavy oil emulsified fuel evaporator system according to the present invention as well as on an operation method thereof, based on embodiments shown in Figs. 1 to 6. It is to be noted that, in the embodiments below, a part of same construction as that shown in Fig. 7 is given a same numeral for simplicity of explanation. (First Embodiment) Firstly, an embodiment of operation method of an evaporator system according to the present invention will be described with reference to Fig. 1. In Fig. 1, numeral 21a, 21b, 21c and 21d, respectively, designates a flow control valve, numeral 22a and 22b, respectively, designates a temperature sensor and numeral 23a designates a pressure sensor. The flow control valve 21a is provided in a piping 15a for introducing a separated water content to a preheater 13 from a separator 15 and the flow control valve 21b is provided in a piping for introducing steam to the piping 15a from an auxiliary steam source which is not shown in the figure. Also, the flow control valve 21c is provided in a piping 15d and the flow control valve 21d in a piping 16a. On the other hand, the temperature sensor 22a is provided in a piping 13b either at outlet of the preheater 13 or at inlet of an evaporator 14 and the temperature sensor 22b is provided in a piping 14d. Also, the pressure sensor 23a is provided in a piping 15a. Other construction is substantially same as that of the evaporator system shown in Fig. 7. The flow control valve 21a, which controls flow rate of the water content (steam) as a preheating source medium which is separated at the separator 15 and is introduced into the preheater 13, is opened and closed by a signal from the temperature sensor 22a provided either at the outlet of the preheater 13 or at the inlet of the evaporator 14 so as to control the flow rate of the preheating source medium flowing into the preheater 13 to a constant level of outlet temperature of the preheater 13 or of inlet temperature of the evaporator 14. FurthSer, the flow control valve 21d is opened and closed by a signal from the temperature sensor 22b provided at outlet of the evaporator 14 so as to control flow rate of a heating steam to a predetermined constant level of outlet temperature of the evaporator 14. On the other hand/ the flow control valve 21b, receiving a signal from the pressure sensor 23a in the piping 15a through which the preheating source medium flows, regulates flow rate of the steam from the auxiliary steam source (not shown) so as to maintain a constant pressure in the piping 15a. Also, the flow control valve 21c controls flow rate to be extracted outside of the system of the separated steam as the preheating source medium generated at the separator 15 and flowing in the piping 15a so as to maintain a constant pressure in the piping 15a. As mentioned above, the outlet temperature of the preheater 13 (or the inlet temperature of the evaporator 14) is detected and the flow control valve 21a is opened and closed so as to maintain this temperature constant, thereby the flow rate of the preheating source medium at the inlet of the preheater 13 is controlled. Further, the pressure in the piping for supplying the preheating source medium is detected by the pressure sensor 23a and, based on the signal from the pressure sensor 23a, the flow control valves 21b and 21c are opened and closed so as to maintain the constant pressure- Thus, with the constant supply pressure of the preheating source medium and the constant inlet temperature of the evaporator 14, the operation control is facilitated. In the operation control state with the constant inlet temperature of the evaporator 14, the outlet temperature of the evaporator 14 is controlled to a predetermined temperature, thus as is clear from a temperature relationship shown in Fig. 2, such an operation control as controls the water content in the heavy oil fuel to a desired value is realized and a constant and stable operation of the entire system becomes possible as well. Furthermore, in case of load change, the flow rate of the emulsified fuel flowing into the preheater 13 is increased or decreased and the temperature, pressure and flow rate at each of the above-mentioned portions change corresponding thereto, but by employing the operation control method as mentioned above, a rapid change in the inlet temperature and outlet temperature of the evaporator 14 and the pressure of the preheating source medium in the piping 15a is avoided so as to be suppressed into a slow change. As the result, change in the water content remaining in the heavy oil fuel after separated of its water content is avoided, and even in the case of load change, the operation to control the water content to a substantially constant and stable level becomes possible in the entire evaporator system as well. (Second Embodiment) Next, a second embodiment will be described with reference to Fig. 3. In Fig. 3, numeral 31 designates a buffer tank, which is provided in a middle of a piping 13b for leading an emulsified fuel to an evaporator 14 from a preheater 13. Alternatively, in place of the buffer tank 31, a preheater of such a structure that a volume outside of a heat exchanger tube 13a (a portion where the emulsified fuel flows) in the preheater 13 is an increasable amount, which term "increasable amount" is defined to mean an amount of the emulsified fuel eguivalent to one hour or more supplied into the evaporator 14 within a time range while there occur load changes. other construction than the above is substantially same as that of the evaporator system shown in Fig. 1 and Fig. 7. In such emulsified fuel evaporator system shown in Fig. 3, the emulsified fuel of the increasable amount which has been preheated controlledly to a predetermined temperature can be stored in advance in the buffer tank 31 or in the preheater 13. In case of load change, for example load increase, in a combustion system (boiler and the like) for burning the separated heavy oil, rotation of a pump 12 is increased to increase supply amount of the emulsified fuel into the preheater 13, that is, flow rate of the emulsified fuel to be introduced into the emulsified fuel evaporator system/ and because the emulsified fuel of predetermined temperature is stored in advance in the increasable amount, the temperature of the emulsified fuel flowing into inlet of the evaporator 14 is maintained constant always within the range of time of the load change. Thus, simply by controlling the flow rate of heating steam as heating source medium to be supplied into the evaporator 14 so as to maintain outlet temperature of the evaporator 14 to a predetermined level, such an operation as is able to supply the heavy oil fuel having a predetermined amount of water content after separation of its water content, that is, the heavy oil fuel having a predetermined amount of water content irrespective of increase or decrease in the flow rate of the heavy oil fuel to be supplied into the combustion system, can be attained easily along the relationship shown in Fig. 2. In the evaporator system of the second embodiment as mentioned above, the emulsified fuel of predetermined temperature in the increasable amount is stored in advance in the buffer tank 31 or in the preheater 13, hence even in such an operation as cannot avoid a load change operation or in such an operation state within a time range while supply amount of the emulsified fuel to the preheater 13 increases or decreases, inlet temperature of the evaporator 14 is maintained constant always and by controlling outlet temperature of the evaporator 14 to a predetermined temperature, the water content in the heavy oil fuel after separation of its water content can be controlled to a predetermined value easily. (Third Embodiment) Next, an emulsified fuel evaporator system of a third embodiment according to the present invention will be described with reference to Fig. 4 . In this evaporator system of the third embodiment, preheaters 41 and 42 in two-stages or more are provided in place of the preheater 13 in Fig. 1. It is to be noted that the preheaters 41 and 42 may be of a single unit of preheaters or a parallel arrangement of plural pieces. Also, a level switch 44a and a control valve 44b of a preheating source medium are provided to the preheater 41. The preheaters 41 and 42 have such heating area and structure that provide following functions in terms of heating characteristics. That is, an operation is controlled such that water level of the preheating source medium in the preheater 41 is controlled by the control valve 44b opened and closed by a signal from the level switch 44a so that the preheating source medium of steam state may not be introduced into the next preheater 42 from the preheater 41. As the result, a separated steam from the preheating source medium separated at a separator 15 and sent to the preheater enters first a heat exchanger tube 41a in the preheater 41 to change to a hot water state from the steam (gas) state through heat exchange with the surrounding emulsified fuel and is then introduced into a heat exchanger tube 42a of the next preheater 42 likewise to preheat the emulsified fuel and is discharged out of the system via a piping 15b. In the separated steam as the preheating source medium separated at the separator 15, there is mixed a light oil content and if such a case has occurred that flow velocity in the piping has become several tens m/s or more or has reached a critical velocity, the light oil content is suspended in the hot water to be discharged outside of the system from the preheater so that it is hardly removed of the drainage by a usual oily water separating equipment and drainage into rivers and the like becomes impermissible. On the other hand, if a single preheater is used, heat utilization must be done such that the preheating source medium changes to a low temperature hot water state from a high temperature steam state in that single preheater, but because exchange heat amount changes in proportion to amount of the emulsified fuel flowing in the preheater, position of a transition region between steam state and hot water state of the preheating source medium varies. As heat transfer characteristics between steam and hot water are different largely from each other, if steam or hot water is unknown of the preheating source medium in the preheater, an accurate design of the heating area will be difficult resulting unaboidably in a design with a large allowance, which brings on an enlarged structure and an increased cost. On the contrary, in the present third embodiment, such a heat exchanger is employed that the preheating source medium is the steam and high temperature hot water in the preheater 41 and the high temperature hot water and low temperature hot water in the preheater 42, thereby evaluation of heat transfer characteristics in the respective preheater becomes facilitated. Thus, by employing a heat exchanger mainly for steam and a heat exchanger mainly for hot water, individual design with a high accuracy becomes possible and a compact-sized structure and a reduced cost can be attained. Further, in the system of piping wherein the hot water level in the preheater is detected and controlled, such an operation control as causes a small volume of hot water to flow so that the flow velocity of the preheating source medium in the state of steam is not 10 m/s or more or does not reach a critical velocity can be done easily. That is, an operation control is done so that the flow velocity in the piping becomes several tens m/s or less, a suspended state of the light oil content in the preheating source medium can be avoided, a subseguent oil content removal by a usual oily water separating equipment can be done easily and drainage into rivers and the like becomes possible. (Fourth Embodiment) A fourth embodiment shown in Figs. 5 and 6 will be described. Figs. 5 and 6 show only a separator 15 to be used for an evaporator system of the present invention. The separator 15 shown in Pig, 5 has a structure wherein there are provided at opening portions on a side face thereof a transmitter 51 and receivers 52a, 52b and 52c. Said transmitter 61 and receivers 52a, 52b and 52c may be provided also in a plurality of sets thereof. If there occurs a pressure reduction action in the separator 15, water content in the emulsified fuel heated to a high temperature at an evaporator flashes (vaporizes) rapidly and gets out hardly of a surrounding high consistency heavy oil fuel resulting in a state of bubbles in which the heavy oil fuel surrounds the steam of gas. Sound wave is transmitted from the transmitter 51 at the opening portion on a side of vessel and is received by the receivers 52a, 52b and 52c provided upward and downward at the opening portions in the opposing wall. When the sound wave passes in the separator 15, there are differences in the velocity passing through the air and the heavy oil fuel and steam in the emulsified fuel and these differences in the receiving time of sound wave are measured and processed by a measuring device and computing device (not shown). In a normal operation state, the emulsified fuel is separated completely into the water content (steam) and the heavy oil fuel at the separator 15 and there is substantially only the steam in the range where the sound wave is projected from the transmitter 51 resulting in a constant receiving time. On the contrary, if there occur said bubbles, the heavy oil fuel increases in place of the steam resulting in variations in the receiving time of sound wave. Thus, a continuous prior detection of bubble generation phenomena in an abnormal operation becomes possible and discharge of the heavy oil fuel out of the system due to overflow can be prevented. Further, by a spreading energy of the sound wave, defoaming effect can be expected as well. As described above, according to the operation method of the heavy oil emulsified fuel evaporator system of the present invention, outlet temperature of the preheater or inlet temperature of the evaporator is controlled constant, pressure in the preheating source medium supply piping for leading the preheating source medium into the preheater is controlled constant and temperature difference between the inlet temperature and the outlet temperature of the evaporator is controlled constant, thereby even in a case of load change, variations in the water content in the heavy oil fuel after separation of water content can be avoided. Also, in said operation method, a construction for storing the preheated emulsified fuel of the increasable amount in the preheater or between the preheater and the evaporator is employed, thereby even in a case of load change, the emulsified fuel of predetermined temperature can be supplied into the inlet of the evaporator and the water content in the heavy oil fuel can be maintained to a predetermined value easily. Further, the present invention provides a heavy oil emulsified fuel evaporator system in which the preheater for preheating the heavy oil emulsified fuel of which water content is to be separated is constructed of a first heat exchanger using steam as the preheating source medium and having a level switch and a second heat exchanger communicating with the first exchanger via the flow control valve and using hot water as the preheating source medium so that the heavy oil emulsified fuel to be preheated is flown to the first heat exchanger from the second heat exchanger. In said evaporator system, the heat exchanger, which is the preheater, is divided into the first heat exchanger using steam and hot water as the preheating source medium and the second heat exchanger using hot water only as the preheating source medium, hence evaluation of the heat transfer characteristics becomes easy and design of a high accuracy becomes possible. Further^ hot water level in the preheater is controlled, thereby light oil content in the preheating source medium is prevented from becoming a suspended state. Also, the present invention provides an evaporator system employing a separator having a transmitter for transmitting a sound wave and a receiver for receiving the sound wave, thereby bubble generation phenomena in the separator can be detected in advance continuously, so that discharge of the heavy oil fuel out of the system due to overflow can be prevented. It is understood that the invention is not limited to the particular construction and arrangement herein illustrated and described but embraces such modified forms thereof as come within the scope of the following claims. WE CLAIM: 1. A method of operating an emulsified fuel evaporator system comprising preheating emulsified fuel in a preheater so as to obtain a preheated emulsified duel; regulating a temperature of the preheated emulsified fuel such that the temperature of the preheated emulsified fuel is maintained constant; heating the preheated emulsified fuel in an evaporator so as to obtain a heated emulsified fuel regulating an evaporator differential temperature such that the evaporator differential temperature is maintained constant; separating the heated emulsified fuel in a separator so as to obtain a water portion and a heavy oil portion, the water portion comprising a preheating medium channeled to the preheater for said preheating of the emulsified fuel; regulating a pressure of the preheating medium such that the pressure of the preheating medium is maintained constant; and transmitting sound waves through the separator. 2. The method as claimed in claim 1, wherein the preheated emulsified fuel is stored in a buffer portion, wherein the buffer portion is located in the preheater or in a piping portion between the preheater and the evaporator. 3. The method as claimed in claim 1, wherein said regulating of the temperature of the preheated emulsified fuel comprises the steps of detecting a temperature of the preheated emulsified fuel from the preheater; and controlling an operation of a preheating medium flow control valve based on the detected temperature of the preheated emulsified fuel so as to control a flow rate of the preheating medium to the preheater. 4. The method as claimed in claim 3, wherein said regulating of the evaporator differential temperature comprises the steps of detecting a temperature of the heated emulsified fuel food the evaporator; and controlling an operation of a heating steam flow control valve based on the detected temperature of the heated emulsified fuel so as to control a flow rate of heating steam to the evaporator. 5. The method as claimed in claim 1, wherein said regulating of the evaporator differential temperature comprises the steps of detecting a temperature of the heated emulsified fuel I’m the evaporator; and controlling an operation of a heating stern flow control valve based on the detected temperature of the heated emulsified fuel so as to control a flow rate of heating steam to the evaporator. 6. The method as claimed in claim 1, wherein said regulating of the pressure of the preheating medium comprises the steps of detecting a pressure of the preheating medium from the esparto; controlling an operation of an auxiliary steam flow control valve based on the detected pressure of the preheating medium so as to control a flow rate of auxiliary steam into the preheating medium; and controlling an operation of an extraction steam flow control valve based on the detected pressure of the preheating medium so as to control a flow rate of extracted preheating medium food the preheating medium. 7. The method as claimed in claim 6, wherein said regulating of the evaporator differential temperature comprises the steps of detecting a temperature of the heated emulsified fuel food the evaporator; and controlling an operation of a heating steam flow control valve based on the detected temperature of the heated emulsified field so as to control a flow rate of heating steam to the evaporator. 8. The method as claimed in claim 6, wherein said regulating of the temperature of the preheated emulsified finial comprises the steps of detecting a temperature of the preheated emulsified the preheater; and controlling an operation of a preheating medium flow cant-ol valve based on the detected temperature of the preheated emulsified field so as to control a flow rate of the preheating medium to the preheater. 9. The method as claimed in claim 8, wherein said regulating of the evaporator differential temperature comprises the steps of detecting a temperature of the heated emulsified the evaporator; and controlling an operation of a heating stem flow control valve based on the detected temperature of the heated emulsified field so as to control a flow rate of heating steam to the evaporator. 10. An emulsified field evaporator system comprising; a preheater having a first heat exchanger using steam as a preheating medium and a second heat exchanger using hot water as a preheating medium, said second heat exchanger communicating with said first heat exchanger through a flow control valve, a level switch being provided at said first heat exchanger for detecting a preheating medium level in said first heat exchanger, said level switch being connected to said flow control valve so as to operate said flow control valve based on the detected preheating medium level, wherein the emulsified f is preheated in said preheater by entering said second heat exchanger and flowing from said second heat exchanger to said first heat exchanger; an evaporator communicating with said preheater such that preheated emulsified fuel flows from said preheater to said evaporator; a separator communicating with said evaporator such that heated emulsified fuel flows from said evaporator to said separator, said separator being capable of separating the heated emulsified fuel into a water portion and a heavy oil portion, said separator communicating with said preheater so that the water portion comprises the preheating medium used in said preheater; and a sound wave component for transmitting sound waves through said separator. 11. The emulsified fuel evaporator system as claimed in claim 10, wherein said sound wave component has a plurality of openings arranged in a vertical direction along a side wall of said separator, at least one transmitter provided at said openings for transmitting a soild wave, and at least one receiver provided at said openings for receiving the sound wave transmitted by said at least one transmitter. 12. A method of operating an emulsified fuel evaporator system, substantially as herein described with reference to figures 1 to 6 of the accompanying drawings. 13. An emulsified feel evaporator system substantially as herein described with reference to figures 1 to 6 of the accompanying drawings.

Documents:

1719-mas-1998 abstract duplicate.pdf

1719-mas-1998 abstract.pdf

1719-mas-1998 claims duplicate.pdf

1719-mas-1998 claims.pdf

1719-mas-1998 correspondence others.pdf

1719-mas-1998 correspondence po.pdf

1719-mas-1998 description (complete) duplicate.pdf

1719-mas-1998 description (complete).pdf

1719-mas-1998 drawings duplicate.pdf

1719-mas-1998 drawings.pdf

1719-mas-1998 form-19.pdf

1719-mas-1998 form-2.pdf

1719-mas-1998 form-26.pdf

1719-mas-1998 form-4.pdf

1719-mas-1998 form-6.pdf

1719-mas-1998 others.pdf

1719-mas-1998 petition.pdf