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FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See section 10, rule 13)
1. Title of the invention
A PROCESS FOR PRODUCTION OF BIODIESEL
2. Applicant(s)
Name Nationality Address
TATA CHEMICALS LTD INDIA BOMBAY HOUSE, 24 HOMI MODI STREET, MUMBAI-400001


3. Preamble to the description
PROVISIONAL SPECIFICATION
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 of production of biodiesel using fly ash as a 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 (HCl), 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,
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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 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 recyclability 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
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economical and recyclable 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 from a fatty acid containing material using fly ash as a catalyst is described.
The method provided produces biodiesel in an economically efficient and an environmental friendly manner. As fly ash is a solid catalyst it can be easily separated from the reaction mixture and reused thereby eliminating the need of neutralization step and aqueous washes that are associated with use of conventional catalysts. Moreover, fly ash catalyses both the esterification reaction of the free fatty acids and the transesterification of triglycerides that are present in the fatty acid starting material (free fatty acids and, oils and fats). The process has several advantages. Firstly, the efficiency of the process increases since no acid pre-treatment process and subsequent
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neutralization steps are needed. Also, biodiesel along with glycerine 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. Fly ash 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. Moreover, the use of fly ash provides an alternate to the disposal related concerns of fly ash generated in industries.
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 pre-determined duration of time in the presence of fly ash as catalyst to get a reaction mixture comprising a mixture of biodiesel, methanol and fly ash and recovering the biodiesel from the reaction mixture.
In accordance with an aspect, the reaction is carried out in the presence of a solid catalyst fly ash. 1-5 wt% of fly ash with respect to the fatty acid starting material is used as a catalyst for the reaction. The composition of the fly ash typically varies within the following composition by wt% (5-12) Si02: (2-11) A1203: (0.50-2.0) Fe203 : (35-60) CaO : (0.40-1) MgO : (26-30) S03. If the fly ash has a lower composition of CaO [<35%] a larger proportion of fly ash may be required, in the range of 5 to 30% wt.
A greater than 98% conversion is achieved by the process and preferably greater than 99% conversion is achieved using fly ash as a catalyst. As the fly ash does not dissolve in the reaction mixture, the quality of the biodiesel and glycerol obtained is purer than most conventional processes.
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Fly ash 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 fly ash may be reused as a catalyst for biodiesel production without loss of catalytic activity.
The reaction mixture includes an upper layer containing biodiesel 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 fly ash as a 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 fly ash; removing the fly ash 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
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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 has 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.
In accordance with an aspect the methanol containing biodiesel rich upper layer may be separated from the methanol 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 methanol 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.
300 g of soyabean oil, 150 g of methanol and 3 g of fly ash were put in batch reactor 180°C under autogenous pressure for 6h. At the end of this time, the reaction mass was allowed to reach room temperature, product mixture drained and catalyst filtered off. Two layers of liquid were present, upper one containing diesel in methanol and glycerol is present in lower layer along with methanol. Two layers of liquid were separated using separation funnel. Methnol was removed by vacuum
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distillation from both the layers separately. A conversion as high as >98% could be achieved using fly ash as catalyst.
Dated this 3rd day of June 2008.
Essenese Obhan Of Obhan & Associates Agent for the Applicant
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