KR100787495B1 - Process for preparing biodiesel - Google Patents

Abstract

The present invention relates to a process for producing biodiesel, in which a fatty acid alkyl ester is produced by esterifying a fat or oil with alcohol, while vacuum distilling the fatty acid alkyl ester produced by the esterification reaction in a distillation process. It provides a method for producing bio-diesel, characterized in that by inhibiting the polymerization of fatty acid alkyl ester.

Via biological

Description

Process for preparing biodiesel

The present invention relates to a method for producing biodiesel, and more particularly, to a method for producing biodiesel having reduced production cost and improved yield.

Biodiesel is a bio-fuel made from fats and oils of vegetable oil and is the most widely used biofuel with bioethanol. It refers to the whole pollution-free fuel made from fats and oils of vegetable oil. It is mainly used as a diesel fuel additive or diesel vehicle fuel by itself.

Biodiesel is usually produced by a transesterification method using a lower alcohol such as methanol to separate glycerol from triglycerides in which glycerol is bound to trivalent fatty acids, and then produce fatty acid esters. The biodiesel made using methanol is fatty acid methyl ester (FAME). So FAME is the common biodiesel.

The ester exchange method using methanol also includes a method using an alkali as a catalyst, a method using a lipase lipase or a supercritical methanol. Alkaline catalysis is the most common, and as the need for biofuels increases, technologies for developing biodiesel are diversifying.

Currently, biodiesel is mixed with diesel fuel or used as a 100% pure fuel. Quality standards are already set in the United States and the European Union. In addition to automotive fuels, it has also been developed for heating fuels, and fuels containing biodiesel mixed with diesel are also sold in Korea.

Looking at the prior art for biological cases, Republic of Korea Patent Publication No. 2004-54318 is characterized in that in the production of known biodiesel oil, comprising the step of esterifying the fat and oil with alcohol using a heterogeneous catalyst A method for producing biodiesel oil using a heterogeneous catalyst is disclosed.

Republic of Korea Patent Publication No. 2004-84515 discloses the reaction rate by adding the ester material produced by the esterification reaction of fats and oils to reflux by adding 1 to 30% to the reaction weight to mix the fats and alcohols in one liquid phase Disclosed is a method for producing biodiesel oil, characterized in that to promote the.

Korean Patent Laid-Open Publication No. 2004-92930 discloses the production of fatty acid esters made by reacting vegetable oils or waste oils with low-molecular alcohols under acidic or alkaline catalysts in place of conventional diesel oils, and then centrifugation and addition of glycerol. Disclosed are a biodiesel fuel that is purified for filtering non-ester materials such as bases, and a method of manufacturing the same.

Korean Patent Registration No. 55353, 1) aromatic hydrocarbons, except 1 to 12% by weight of toluene and xylene 2) 5 to 45% by weight of toluene 3) 3 to 24% by weight of xylene 4) 2 to 39% by weight Bioethanol 5) 1-13 wt% isopropanol 6) 1-12 wt% isobutanol 7) 20-59 wt% diluent 8) 0.5-10 wt% isopentane Is disclosed.

The present invention was developed based on the invention of replacing petroleum gas with fatty acid methyl ester using vegetable oil from ATT in Germany.

This technology uses a transesterification method using KOH as a catalyst and attempts to produce a product using physical refined oil as a raw material, and it is a reality that the marketability has not been expanded due to problems such as an increase in raw materials and production costs.

Accordingly, the present invention has been made to solve the above-mentioned problems, an object of the present invention is to provide a method for producing biodiesel which can reduce the production cost and improve the yield.

In order to achieve the above object, the present invention, in the production of bio-diesel which is a fatty acid alkyl ester by esterification of fats and oils, fatty acid alkyl ester produced by the esterification reaction in a vacuum distillation, the polymerization inhibitor in the distillation process It provides a method for producing biofuel, characterized in that by inhibiting the polymerization of fatty acid alkyl esters.

As the polymerization inhibitor used in the present invention, various kinds of polymerization inhibitors can be used, but the best boric acid is preferable in terms of the effect, and the amount of the polymerization inhibitor is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of fat or oil.

In the present invention, the vacuum degree of the vacuum distillation is 0.001 to 0.9 kg / ㎠, distillation temperature is preferably 220 to 280 ℃. Since the vaporization temperature is lowered when entering the vacuum state, it is preferable to control the temperature to 220 to 280 ° C.

The fat or oil used in the present invention is preferably oxidized vegetable oil, animal or vegetable waste fat and oil, and is very advantageous in terms of resource recycling and manufacturing cost by using waste fat and oil as a raw material.

The present invention is characterized in that the biodiesel is distilled under vacuum drying to improve the yield of biodiesel, and an appropriate amount of a polymerization inhibitor (Polymerization inhibitor) is added in the distillation process to inhibit the polymerization of biodiesel. While the yield of conventional biodiesel is 80% or less, the yield can be improved to 80% or more according to the present invention.

According to the present invention, after the esterification reaction, the distillate is cooled to 0 ° C. and filtered to remove the residue, and thus, the biodiesel obtained is an alternative to the international standard diesel 0 #.

Hereinafter, the production process of biofuel according to the present invention will be described in detail.

First, oil, alcohol and a catalyst are added to the reaction tank. At this time, the weight ratio of the feedstock: alcohol: catalyst is preferably 1,000: 400 to 800: 10.

The fats and oils used in the present invention include oxidized vegetable oils (raw materials obtained by oxidizing waste plants) and animal and vegetable waste fats and oils (sewage oil, waste oil remaining after food manufacturing). Oxidized vegetable oils and animal and vegetable oils and fats consist mainly of fatty acids and glycerides.

The alcohol used in the present invention is a lower alcohol such as methanol, ethanol, propanol, butanol, and methanol is particularly preferable.

The catalyst used in the present invention is an acid catalyst such as sulfuric acid or an alkali catalyst such as potassium hydroxide, and sulfuric acid is particularly preferable.

Subsequently, the esterification reaction is carried out for 4 to 8 hours while maintaining the temperature between 65 and 75 DEG C while maintaining the crude oil and the alcohol having a water content of 5% or less in an reaction tank under acid or alkali catalysis, at normal pressure with steam.

Next, after the completion of the esterification reaction, the excess alcohol is recovered into the column in the form of steam, and the residue is precipitated for about 1.5 hours, the acid is discharged, washed with water and then dehydrated through the dehydration tower.

Next, the polymerization inhibitor is added and stirred, and then distilled by pumping to a distillation column. At this time, the temperature in the distillation column is 220 to 280 ℃, vacuum degree is 0.001 to 0.9 kg / ㎠, preferably maintained at 0.01 to 0.2 kg / ㎠ distillation.

The yield of the effluent is 80-97%, the main components are mixed fatty acid biodiesel and a small amount of unreacted fatty acid.

Next, the extracted effluent is introduced into a cooler, cooled to 0 ° C., and then the solid (residue) is removed through a filter, and the remaining liquid is biodiesel which can substitute diesel 0 #.

Example 1

1,000 kg of oxidized vegetable oil, 650 kg of industrial methanol having a water content of 5% or less, and 10 kg of concentrated sulfuric acid were added to an esterification tank, and the esterification reaction was performed for 6 hours while maintaining the temperature at 70 ° C. by heating with steam under normal pressure.

After completion of the esterification reaction, the acidified water was discharged for 1.5 hours, washed again with water, and dehydrated through a dehydration tower, and methanol vapor was recovered in the methanol absorption tower.

1 kg of boric acid was added to 971 kg of fatty acid methyl ester obtained after dehydration, stirred, and transferred to a distillation tank by a pump to control the temperature of the liquid phase to 250 ° C. and distilled under conditions of vacuum degree of 0.1 kg / cm 2 to 859 kg. Got water.

The effluent was cooled to 0 ° C. in a cooling tower, at which temperature the remaining solids in the effluent were filtered to give 848 kg (yield: 84%) of the desired vegetable fatty acid methyl ester (PME), ie biodiesel.

Flash point of the produced biodiesel has a flash point of ≤85 ° C, viscosity of 8.0 csl (corn steep liquor) (20 ° C), ash content of 0.001%, calorific value of 10,001 ㎉ / kg, CN (cetane number) 51, acid value of ≥5.0 KOH mg / g, there was no mechanical foreign matter and water.

Example 2

After adding 800 kg of tap water, 480 kg of industrial methanol having a water content of 5%, and 8 kg of concentrated sulfuric acid to an esterification reactor, the esterification reaction and dehydration treatment were carried out in the same manner as in Example 1.

After obtaining 776 kg of fatty acid methyl ester, 0.8 kg of boric acid was added, distillation was carried out in the same manner as in Example 1 to obtain 704 kg of effluent, and then, 688 kg of biodiesel obtained by filtration to remove solid residue. %) Was obtained.

Example 3

600 kg of plant waste oil used in the food processing plant, 370 kg of industrial methanol within 5% of water content, and 6 kg of concentrated sulfuric acid were added to the esterification tank, followed by esterification and dehydration in the same manner as in Example 1. It was.

After obtaining 582 kg of fatty acid methyl ester, 0.6 kg of boric acid was added, and then distilled in the same manner as in Example 1 to obtain 528 kg of effluent, and then 516 kg of biodiesel obtained by filtration to remove solid residue. %) Was obtained.

[Test Example]

The main performance test was performed on the biodiesel prepared in Example, and the results are shown in Table 1.

As can be seen in Table 1, the biofuel of the present invention was at least equivalent to that of the general diesel 0 # in the main performance.

In addition, the biodiesel according to the present invention was not significantly different from general diesel fuels such as maneuverability, combustibility, and exhaust temperature. Therefore, it can be seen that the biodiesel according to the present invention may be mixed with commercial diesel.

designation Flash point ℃ Viscosity csi (20 ℃) Ash% Calories ㎉ / ㎏ Cetane number CN Acid Value KOHmg / g Via biological ≤85 8.0 0.001 10,001 51 ≥5.0 Via0 # ≤65 3.0-8.0 ≥0.025 10,200 ≤50

When the biofuel is produced according to the present invention, the production cost can be reduced by using oxidized vegetable oil, waste oil and the like, and the yield can be improved due to the vacuum distillation process including polymerization inhibition.

Claims (6)

In esterification of fats and oils with alcohol to produce biodiesel, which is a fatty acid alkyl ester, A fatty acid alkyl ester produced by the esterification reaction is distilled under vacuum, but a polymerization inhibitor is added during the distillation to inhibit the polymerization of the fatty acid alkyl ester. The method according to claim 1, wherein the polymerization inhibitor is boric acid. The method according to claim 1 or 2, wherein the amount of the polymerization inhibitor is 0.1 to 5 parts by weight based on 100 parts by weight of fat or oil. The method according to claim 1, wherein the vacuum degree of vacuum distillation is 0.001 to 0.9 kg / cm 2. The method of claim 1, wherein the distillation temperature is 220 to 280 ℃. The process for producing biopetroleum according to claim 1, wherein the fat or oil is oxidized vegetable oil, animal or vegetable waste fat or oil.