|Title of Invention
A PROCESS FOR PRODUCTION OF ALKYL ESTERS
|The invention relates to a process for producing alkyl esters, the process comprising reacting a feedstock that includes one or more fatty acid glycerol esters or one or more fatty acid or mixture thereof with a C1 to C4 alcohol in the presence of a catalyst at a temperature substantially 100° C or more, the catalyst including a catalyst composition comprising oxides, mixed oxides, silicates or sulphates of two or more of silica, aluminium, iron, calcium, magnesium, sodium and potassium.
THE PATENTS ACT, 1970
(39 of 1970)
THE PATENTS RULES, 2003
(See section 10, rule 13)
1. Title of the invention
A PROCESS FOR PRODUCTION OF BIODIESEL
Name Nationality Address
TATA CHEMICALS LTD INDIA BOMBAY HOUSE, 24 HOMI MODI STREET, MUMBAI-400001
3 3. Preamble to the description
The following specification particularly describes the invention.
The invention relates to a process for production of biodiesel. More particularly the invention relates to a process for production of biodiesel using a nanocomposite catalyst. DESCRIPTION OF RELATED ART
Biodiesel is a non-petroleum based fuel that consists of alkyl esters, made from vegetable oils or animal fats. The alky esters generated from the oils and fats can be appropriately blended with petroleum diesel that makes the blend suitable for use in diesel engine. Moreover, biodiesel is a biodegradable and non toxic alternative to diesel fuel. As a result biodiesel is becoming increasingly useful as a "green fuel".
Commercial production of biodiesel is carried out by a transesterification reaction of vegetable oil or animal fat. Vegetable oil or animal fats is reacted with alcohol (such as methanol or ethanol) to convert the triglyceride in oils and fats to alkyl esters (biodiesel) and a glycerine by-product. Since this reaction is extremely slow, the reaction is carried out at elevated temperature and in the presence of a catalyst.
Most commercial processes for the production of biodiesel currently use a homogeneous alkali catalyst at 60-65°C. While the homogeneity of the reaction mass enhances the conversion rate, the catalyst is part of the reaction product. This makes it necessary to carry out a complicated step of separation and/or removal of the catalyst. The process of separating biodiesel from catalyst and glycerol involves a neutralization process with strong acids, such as hydrochloric acid (HC1), and extensive washes with water to remove the resulting sodium chloride salt. Further, in order to remove sodium chloride from glycerol and to obtain glycerol in high purity, distillation of high boiling glycerol has to be carried out which is an energy intensive operation.
The use of alkali catalyst also cause saponification of free fatty acids contained in fats
and oils to form soaps as by products, whereby it becomes necessary to carry out a step of
washing with large amounts of water. In addition, the yield of alkly esters (biodiesel)
decreases due to the emulsification effect of the soaps generated and, in certain instances the subsequent glycerine purification process also becomes complicated. In order to overcome the problem associated with free fatty acids, a strong homogeneous acid like sulphuric acid is sometimes used as a pre-treatment catalyst that converts free fatty acids to alkyl esters. However, if acid is used in the pre-treatment process, neutralization of oil has to be done before transesterification reaction may be carried out. This further creates economical and environmental concerns.
In order to overcome the problems associated with use of a homogeneous catalyst, heterogenous solid catalysts for the transesterification of oils to biodiesel have been developed. For example, various basic metal oxides, such as magnesium methoxide, calcium oxide, calcium alkoxide, and barium hydroxide, have been demonstrated to be active catalysts for transesterification. However, the re-cyclability of these solid base catalysts is poor. This is because of the moderate solubility of some of these solid metal oxides and hydroxides in methanol and strong physical adsorption of the reaction products on their surfaces.
In view of these drawbacks, there is a need to develop a process for biodiesel production that does not require tedious aqueous washes and neutralization steps. An economical and re-cyclable catalyst that can be easily separated from the biodiesel products for the conversion of oils to biodiesel is also needed. Moreover a catalyst that can economically catalyse both the esterification of free fatty acids and transesterify oils to biodiesel is desirable. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
To promote an understanding of the principles of the invention, reference will be
made to the embodiment and specific language will be used to describe the same. It will
nevertheless be understood that no limitation of scope of the invention is thereby intended,
such alterations and further modifications in the illustrated system and such further applications of the principles of the inventions as illustrated therein being contemplated as would normally occur to one skilled in art to which the invention relates.
A method for the production of biodiesel is described. More particularly a method of production of biodiesel using a nanocomposite catalyst comprising of oxide of silica, alumina, calcium and iron is described.
The method provided produces biodiesel in an economically efficient and an environmental friendly manner. As the solid nanocomposite catalyst can be easily removed from the reaction mixture thereby eliminating the need of neutralization step and aqueous washes that are associated with use of conventional catalysts. Moreover the nanocomposite catalyst is such that it catalyses both the esterification of the free fatty acid and the transesterification of triglycerides present in the fatty acid staring material (free fatty acids, oils and fats). The process has several advantages. Firstly, the efficiency of the process increases since no acid pre-treatment process and subsequent neutralization steps are needed. Also, biodiesel along with glycerol is generated as the only reaction product without any contaminations. This enables easy separation of the two immiscible layers from the catalyst, yielding biodiesel in quantitative yield that needs no further purification. The catalyst separated from the reaction mixture does not lose its catalytic activity and may be reused as a catalyst, thereby reducing the cost of biodiesel production.
The process of production of biodiesel comprises of reacting a fatty acid, or any material containing fatty acids with an alcohol at an elevated temperature for a predetermined period of time in the presence of a nanocomposite catalyst to get a reaction mixture wherein the reaction mixture contains a mixture of biodiesel, alcohol, glycerol and catalyst and recovering the biodiesel from the reaction mixture.
The reaction is carried out in the presence of a nanocomposite comprising of oxides of silica, alumina, calcium and iron as a catalyst. In accordance with an aspect of the invention the nanocomposite catalyst is selected from a group consisting of Tricalcium silicate , Calcium silicate Tricalcium aluminate and Tetracalcium
aluminoferrite In accordance with an aspect the composition of the
nanocomposite varies within the range by
According to as aspect of the invention the catalyst particles have a size ranging from 5 nm to 1000 nm. The nano particles of the catalyst increase the catalysis rate of the reaction and the selectivity of the product that is formed. l-5wt% of catalyst with respect to the fatty acid starting material is used for the reaction.
A greater than 98% conversion is achieved by the process and preferably a greater than 99% conversion is achieved using the nanocomposite as catalyst. As the catalyst does not dissolve in the reaction mixture, the quality of the bio diesel and glycerol obtained is purer than most conventional processes.
The catalyst is easily recovered from the reaction mixture by any method including gravitational settling, filtration, centrifugation or any combination thereof.
In accordance with an aspect once separated the nanocomposite may be reused as a catalyst for biodiesel production without loss of catalytic activity.
The reaction mixture includes an upper layer containing chiefly biodiesel along with traces of mono-, di- and tri glyceride and alcohol and, a lower layer containing glycerol and alcohol. Recovery of biodiesel from the reaction mixture is carried out by separating the catalyst from the reaction mixture. The biodiesel is recovered from the upper layer and separated from the glycerol rich lower layer and alcohol is removed from the two layers.
In accordance with an aspect, the production of biodiesel comprises of reacting fatty acid containing starting material with an alcohol in the presence of nanocomposite catalyst at an elevated temperature and autogenerated pressure for a predetermined period of time to get a reaction mixture, wherein the said reaction mixture contains a mixture of biodiesel, glycerol, alcohol and catalyst; removing the catalyst from the said reaction mixture by filtration to get a liquid with two phases, the alcohol containing biodiesel rich upper layer and alcohol containing glycerol rich lower layer; separating the two phase by separating funnel and removing the alcohol from biodiesel and glycerol rich liquids by vacuum distillation to get biodiesel and glycerol.
The fatty acid starting material may contain fatty acids as free fatty acids or as triglycerides of glycerol or their mixture. The fatty acid staring material for this invention may be any fatty acid rich material including but not limited to vegetable oil, used vegetable oil, restaurant waste grease, or surplus liquid or solid fats such as vegetable shortening, surplus margarine or animal fats. Fatty acid starting material used for this reaction may be used individually or as a mixture with other fatty acid containing material.
In accordance with an aspect, additional processing such as removal of excess water or filtering out of precipitate may be required before using animal or vegetable fat for this process.
In accordance with an aspect, the alcohol to be used, for the reaction may be any alcohol, including but not limited to methanol, ethanol, propenol and butanol. Single alcohol or a mixture of two or more alcohols may be used for the reaction.
In accordance with an aspect the reaction is carried out at an elevated temperature of
60-200°C under autogenerated pressure to high pressure, for a period of upto 24 hours.
In accordance with an aspect the alcohol containing biodiesel rich upper layer may be
separated from the alcohol containing glycerol rich lower layer by any method including but
not limited to gravitational settling, centrifugation, distillation, using separation funnel or a combination thereof. According to a preferred embodiment alcohol is removed from biodiesel and glycerol by vacuum distillation.
The following example is provided to explain and illustrate certain preferred embodiments of the process of the invention.
300g of soyabean oil, 150g of methanol and 30g of nano cement were put in batch reactor at I80°C under autogenous pressure for 6h. Product mixture was collected and catalyst was filtered off. Two layer of liquid were present, upper layer contains diesel (methyl ester of fatty acid) in methanol and glycerol is present in lower layer along with methanol. The two layers of liquid were separated using a separating funnel. Methanol was removed by vacuum distillation from both the layers of liquid separately. As high as >99% conversion of vegetable oil could be achieved using catalytic amounts (ca. 1-5% of nanocomposite with respect to vegetable oil), even under un-optimized reaction conditions. The composition of the nanocomposite varies within following range by wt% (35-71) Ca3Si05: (12-30) Ca2Si04 : (3-20) Ca3Al206 : (1-10) Ca4Al2Fe20,o.
Dated this 10th day of June 2008
Essenese Obhan Of Obhan & Associates Agent for the Applicant
|Indian Patent Application Number
|PG Journal Number
|Date of Filing
|Name of Patentee
|TATA CHEMICALS LTD.
|BOMBAY HOUSE, 24 HOMI MODI STREET, MUMBAI
|PCT International Classification Number
|PCT International Application Number
|PCT International Filing date