KR20170012950A - Method and apparatus for preparing biodiesel from oils containing polar lipids - Google Patents

Abstract

Disclosed are a method and a device for producing biodiesel from raw oil including polar lipids such as phospholipids (PLs) and glycolipids (GLs). The method comprises the following steps: obtaining a byproduct including crude fatty acid and glycerin by hydrolyzing oil including polar lipids; separating fatty acid from a byproduct layer including glycerin and water by delaminating the byproduct generated by hydrolysis to include the crude fatty acid and glycerin; obtaining fatty acid alkyl ester by performing esterification by reacting the separated fatty acid with alcohol; and obtaining a biodiesel fuel by refining the fatty acid alkyl ester.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing biodiesel from an oil containing polar lipids,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing biodiesel, and more particularly, to a method for producing biodiesel from a raw oil containing polar lipids such as phospholipids (PLs) and glycolipids (GLs) Manufacturing apparatus.

Diesel oil is advantageous in fuel efficiency, low cost, and low carbon dioxide generation among various kinds of fuels obtained from crude oil, but there is a disadvantage that many air pollutants are generated after combustion. In order to solve these drawbacks, studies on biodiesel as an alternative natural-cycle fuel that is similar in properties to diesel oil, economically advantageous, and capable of reducing air pollution are being actively conducted. Generally, biodiesel is produced by ester-exchange reaction of triglyceride (triacylglycerol) (TAG) contained in vegetable oils (lipids) such as rapeseed oil, soybean oil, sunflower oil, palm oil, etc. with an acid catalyst or an alkali catalyst (Transesterification). That is, in most commercial biodiesel production processes, an ester exchange reaction between triglyceride and alcohol is used, and an acid catalyst or a base catalyst is used to increase the ester exchange reaction rate. According to the reported data, the reaction time is more than 30 hours for acid catalysts and more than 2 hours for base catalysts. Therefore, base catalysts are preferred in terms of reaction time. Free fatty acids ; FFAs) is high (acid value is 1 or more), there is a problem that the catalyst is lost by the saponification reaction of the base catalyst and the conversion of triglyceride is lowered.

Korean Patent Laid-open Nos. 10-2007-0106236 and 10-2010-0051374 filed by the present applicant disclose a process for producing a fatty acid alkyl ester by esterification reaction of a fatty acid and an alcohol without using a catalyst, A method and an apparatus for obtaining a fatty acid alkyl ester are disclosed. In Korean Patent Application No. 10-2014-0135030 of the present applicant, a fatty acid is produced by hydrolyzing a neutral lipid (mono, di, triglyceride and free fatty acid) containing a large amount of free fatty acid under high temperature, high pressure, And a method and an apparatus for producing a fatty acid alkyl ester by an esterification reaction with an alcohol. The above methods are for producing biodiesel using a neutral lipid raw material containing a large amount of free fatty acid and solved the problem that arises when the content of free fatty acid in the raw material is high.

However, as the use of biodiesel has recently increased, the price of vegetable oil as a raw material for producing biodiesel has risen, and the problem of lack of food resources and land resources has been raised around the world. Therefore, production of biodiesel using non-edible raw materials There is a growing need. Microalgae, a typical non-edible raw material, is a single-celled organism that grows by photosynthesis using water, carbon dioxide and sunlight, also known as phytoplankton. The microalgae have a high growth rate and high oil productivity (58,700 ~ 97,790 L / ha) per unit area of soybean (446 ~ 635 L / ha) and oil palm (5,366 ~ 5,950 L / ha), which is attracting attention as a third-generation non-edible raw material for producing biodiesel.

However, the oil produced by microalgae has the following problems. In the case of plants, most of the lipids produced by photosynthesis are stored in seeds in the form of triglycerides, and the extract of these seeds is the main raw material for the production of biodiesel. On the other hand, microalgae are single cell organisms in which photosynthetic organs and storage organisms coexist. In addition to triglycerides, which are storage lipids, they contain large amounts of polar lipids such as phospholipids (PLs) and glycolipids (GLs) Among the total lipids of microalgae, the amount of lipid used in the actual biodiesel synthesis is greatly reduced. Plant seeds also contain small amounts of polar lipids, which reduce the yield of biodiesel by making it difficult to separate fatty acid alkyl esters in conventional biodiesel conversion processes that use transesterification, P) content. Thus, oils extracted from plant seeds are generally used for biodiesel production after removal of polar lipids through degumming and neutralization processes. Untreated plant seed oil contains less than about 3% of polar lipids. Removal of these small amounts of polar lipids may help improve the productivity of biodiesel, but microalgae may contain 20 to 80 wt% If polar lipids are not used in the production of biodiesel because of the inclusion of polar lipids, economical efficiency of biodiesel production using microalgae oil may be reduced.

An object of the present invention is to provide a biodiesel manufacturing method and a manufacturing apparatus which are not only excellent in productivity and economy, but also have a simple process.

Another object of the present invention is to provide a method and an apparatus for producing biodiesel using oil containing polar lipids such as microalgae oil and plant seed oil.

It is still another object of the present invention to provide a method and an apparatus for producing biodiesel from oils containing polar lipids with high conversion and yield.

In order to accomplish the above object, the present invention provides a method for producing an oil-in-water emulsion, comprising hydrolyzing an oil containing a polar lipid to obtain a by-product containing a crude fatty acid and glycerin; Separating the by-product comprising the crude fatty acid and glycerin produced by the hydrolysis reaction to separate the fatty acid from the by-product layer comprising glycerin and water; Reacting the separated fatty acid with an alcohol to carry out an esterification reaction to obtain a fatty acid alkyl ester; And purifying the fatty acid alkyl ester to obtain a biodiesel fuel.

The present invention also relates to a hydrolysis reactor for hydrolyzing an oil containing a polar lipid and separating the hydrolysis reaction product to separate the by-product layer containing glycerin and water from the crude fatty acid; A flash tank for storing the separated crude fatty acid; A water recovery section for separating the solid component from the by-product layer from which the crude fatty acid has been separated by solid-liquid separation and then distilling off the water to obtain concentrated glycerin; An esterification reactor for esterifying fatty acids and alcohols in the flash tank to produce fatty acid alkyl esters and separating water and excess alcohol from the fatty acid alkyl esters in the esterification reaction; And a biodiesel distillation column for separating the biodiesel by distilling the separated fatty acid alkyl ester according to the molecular weight.

According to the method and apparatus for producing biodiesel according to the present invention, not only microalgae oil containing a large amount of polar lipid but also plant seed oil containing a small amount of polar lipid can be used for degumming and the like The biodiesel can be converted into biodiesel at a high yield without performing any additional process, so that the productivity and economical efficiency of biodiesel can be improved.

FIG. 1 is a graph showing species and contents of lipids present in plant seeds and microalgae. FIG.
2 is a view showing an apparatus for manufacturing biodiesel according to an embodiment of the present invention.
FIG. 3 is a diagram showing the lipid composition and content of soybean lecithin and the results of TLC (thin layer chromatography) analysis of raw lecithin and hydrolyzed lecithin.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the production of biodiesel according to the present invention, the "polar lipid-containing oil" used as a starting material is a polar lipid such as phospholipids (PLs), glycollipids (GLs) ; PLs), and refers to oils other than polar lipids, such as Neutral Lipids (NLs, monoacylglycerol (MAG), diacylglycerol (DAG), triacylglycerol (TAG), free fatty acid (FFA), etc.) and impurities such as carbohydrates, proteins, and pigments. Examples of the phospholipids (PLs) include phosphatidylcholine (PC), phosphatidyl ethanolamine (PE) and the like, and glycolipids (GLs) Examples of the lipid contained therein include monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and the like. In the above-mentioned "oil containing polar lipid ", the content of the polar lipid is 3 to 100% by weight, preferably 3 to 50% by weight, more preferably 3 to 20% by weight and the content of the neutral lipid is 0 To 97% by weight, preferably 50 to 97% by weight, more preferably 80 to 97% by weight, and the balance may be other impurities. Here, when the content of the polar lipid is large, productivity of the oil can be increased, and even if the amount of the polar lipid is small, omission of the defection process can be economically achieved. In the "oil containing polar lipid", the content of the aliphatic hydrocarbon chain having 6 to 24 carbon atoms relative to the total aliphatic hydrocarbon chain constituting the fat and fatty acid component is preferably 3 to 100% by weight, 5 to 95% by weight, more preferably 15 to 90% by weight, most preferably 50 to 85% by weight, and the remaining aliphatic hydrocarbon chain has less than 6 carbon atoms or more than 24 carbon atoms.

The "oil containing a polar lipid" is a plant seed oil or a micro-algae oil obtained by squeezing or extracting a microalgae such as edible or non edible plant seeds, marine microalgae, freshwater microalgae, And, if necessary, can be used without removing or removing proteins and sugars from them. FIG. 1 is a chart showing the kinds and contents of lipids present in plant seeds and microalgae. FIG. As shown in Fig. 1, vegetable oil contains 90 to 98% of neutral lipids (NLs, less than 3% of free fatty acid (FFAs)), 0.5 to 3% of phospholipids (PLs) and less than 1% Microalgae oil contains 20 to 40% of neutral lipids (NLs), 10 to 20% of phospholipids (PLs) in growth under nitrogen-rich conditions (+ N) (NLs), 10 to 20% of phospholipids (PLs) and 10 to 20% of phospholipids (PLs) when grown under nitrogen-deficient conditions % Of glycolipids (GLs), where% represents wt%. As described above, the "oil containing a polar lipid" used in the present invention may contain not only the neutral lipid used as a raw material for conventional biodiesel production but also the polar lipid which has been removed through a degumming process.

In the method for producing biodiesel according to the present invention, first, the starting material "oil containing polar lipid" is hydrolyzed to obtain a by-product containing Crude fatty acid (CFA) and glycerine. The hydrolysis (hydrolysis reaction) of the "oil containing polar lipids " can be carried out by reacting water with a" oil containing polar lipid " under high temperature and high pressure conditions, &Quot; oil "comprising < / RTI > The hydrolysis reaction temperature of the oil and water is 200 to 280 ° C, preferably 220 to 260 ° C, more preferably 240 to 260 ° C .; the reaction pressure is 30 to 80 bar, preferably 40 to 60 bar , More preferably from 50 to 60 bar. If the temperature of the hydrolysis reaction is too low, the solubility of water in the fat decreases and the reaction rate becomes slow, and the conversion of the unreacted fat increases due to the reaction equilibrium, There is a concern. In addition, if the hydrolysis reaction pressure is too low, water may not exist in a liquid state in the reactants, resulting in a decrease in conversion. If the hydrolysis reaction pressure is too high, the design pressure of the reaction equipment is high and the equipment cost is increased. The hydrolysis yield can be controlled by controlling the temperature, pressure, time, stirring speed, and water content of the hydrolysis reaction. As the enzyme that hydrolyzes the oil containing the polar lipid, an enzyme capable of separating a fatty acid from monoacylglycerol, diacylglycerol, triacylglycerol, phospholipid, glycolipid and the like can be used. For example, A lipase obtained from a microorganism, a plant or an animal can be used.

Next, crude fatty acid (CFA) produced by the hydrolysis reaction is separated into glycerin-containing byproducts, and the fatty acid is separated from a by-product layer (water layer) containing glycerin and water. At this time, it is preferable to improve the conversion ratio from the above-mentioned "oil containing polar lipid" to fatty acid (for example, conversion rate, that is, degree of splitting is 50 or more, preferably 70 or more, more preferably 80 or more, 90 or more, see Examples) That is, when the amount of the phospholipid acting as a surfactant is reduced by improving the hydrolysis yield, the separation of the fatty acid and the by-product layer is more preferable. Further, the by-product layer may be formed by solid-liquid separation such as phosphate, carbide (Char, fatty acid, glycerol, sugar, protein and other organic substances produced by carbonization at high temperature) And then distilling off the water to obtain concentrated glycerin, and the distilled water can be reused for the hydrolysis reaction.

Next, the separated fatty acid is reacted with an alcohol to carry out an esterification reaction to obtain a fatty acid alkyl ester, and if necessary, it is purified to obtain a biodiesel fuel. The esterification reaction of the fatty acid can be carried out by a conventionally known method, for example, by the method disclosed in Korean Patent Application Laid-Open Nos. 10-2007-0106236 and 10-2010-0051374, But is not limited thereto. As the alcohol used in the esterification reaction, a monohydric alcohol having 1 to 10 carbon atoms, preferably a lower monohydric alcohol having 1 to 4 carbon atoms such as methanol, ethanol, propanol and the like can be used, and methanol is particularly preferably used. The temperature of the esterification reaction is 200 to 350 DEG C, preferably 230 to 320 DEG C, and the reaction pressure is atmospheric pressure to 35 bar, preferably 1 to 20 bar, more preferably 3 to 10 bar. If the temperature of the esterification reaction is too low to effectively remove the water in the reaction product, the unreacted fatty acid component remains due to the reaction equilibrium. This increases the total acid value (mg KOH / g) of the fatty acid alkyl ester, There is a problem that the quality criterion of the organic material is not satisfied, and when it is too high, there is a problem that the organic material is pyrolyzed or carbonized. If the esterification reaction pressure is too low, the solubility of the alcohol in the gaseous state in the reaction state is low and the solubility of the alcohol in the reaction state is low. If the esterification reaction pressure is too high, the designing pressure of the reaction equipment is high, Water in the reaction product can not be effectively removed, and unreacted fatty acid components may remain due to the reaction equilibrium.

When the fatty acid alkyl ester obtained by the above esterification reaction is separated from the water produced in the esterification reaction and the excess alcohol and then the fatty acid alkyl ester is distilled in accordance with the molecular weight, not only the biodiesel but also the aliphatic portion has more than 24 carbon atoms Such as heavy oil, containing an aliphatic alkyl ester component. For example, when the temperature of the lower portion of the distillation column is set to 250 to 280 ° C. and the temperature of the upper portion of the distillation column is set to 150 to 200 ° C. at a pressure of 10 torr, the fatty acid alkyl ester for biodiesel is distilled from the upper portion of the distillation column, Residual high boiling point materials can be used as heavy oil. If necessary, low boiling point impurities such as an aliphatic alkyl ester component having an aliphatic moiety having less than 14 carbon atoms can be removed from the top of the distillation tower by distillation.

Next, an apparatus for manufacturing biodiesel according to the present invention will be described with reference to FIG. As shown in FIG. 3, the apparatus for producing biodiesel according to the present invention comprises hydrolyzing a total oil (10) containing a polar lipid and separating the hydrolysis reaction product to obtain a by-product containing glycerin and water A hydrolysis reactor 20 for separating the aqueous layer and crude fatty acid (CFA); A flash tank 22 for storing the separated crude fatty acids; A solid component such as phosphate or Char is separated from the by-product layer in which the crude fatty acid has been separated by solid-liquid separation and then the water is distilled off to remove the water to recover the concentrated glycerin. recovery); An esterification reactor 30 for esterifying fatty acids and alcohols in the flash tank 22 to produce fatty acid alkyl esters and separating water and excess alcohol from the fatty acid alkyl esters in the esterification reaction; And a biodiesel distillation column (product column) 34 for separating the separated fatty acid alkyl esters according to their molecular weights and separating them into biodiesel and, if necessary, heavy oil. At this time, if necessary, low boiling point impurities can be removed through the upper part of the biodiesel distillation column 34 by distillation, and the water and the excess alcohol mixture produced in the esterification reaction are separated in the alcohol recovery distillation column 32, High-purity alcohol can be recovered. For example, the pressure of the alcohol recovery distillation column 32 can be operated at 1 atm, the lower temperature 101 ° C, and the upper temperature 64 ° C.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples illustrate the present invention and are not intended to limit the scope of the present invention.

[Example 1] Hydrolysis of lecithin

a. 50 g of lecithin and 50 mL of water were placed in a 250 mL high-temperature / high-pressure reactor and sealed, followed by hydrolysis reaction at 250 DEG C and 40 bar pressure for 6 hours to prepare crude fatty acids. The obtained reaction product was subjected to layer separation to separate a by-product layer (lower layer) and a fatty acid (upper layer) containing water and glycerin. The degree of splitting of the obtained fatty acid was 89.3, and the amount of char formed was 10.7 g in dry weight. Here, the degree of splitting = Acid Value / Saponificable Value is an index of conversion of the lipolysis process. The Acid Value represents the amount of potassium hydroxide consumed in neutralizing 1 g of free fatty acid and the Saponificable Value represents the amount of potassium hydroxide consumed in saponifying 1 g of fat or fatty acid. Therefore, the conversion value indicates the degree of conversion of fat to fatty acid. The lipid composition and content of representative soybean lecithin and the result of TLC (thin layer chromatography) analysis of raw lecithin and hydrolyzed lecithin are shown in FIG. (PA), phosphatidyl inositol (PI), phosphatidyl ethanolamine (PE), and phosphatidyl serine (PS), respectively. .

b. A crude fatty acid was prepared by carrying out a hydrolysis reaction in the same manner as in Example 1, except that the hydrolysis reaction of lecithin and water was carried out with stirring at 350 rpm. The degree of splitting of the obtained fatty acid was 89.5, and the char formed was 6.1 g as dry weight.

c. A hydrolysis reaction was carried out in the same manner as in Example 1, a, except that 50 g of lecithin and 100 mL of water were subjected to a hydrolysis reaction at 350 rpm for 2 hours while stirring, to prepare a crude fatty acid. The degree of splitting of the obtained fatty acid was 92.4, and the generated char was 2.9 g in terms of the non-dry weight.

d. Hydrolysis was carried out in the same manner as in Example 1 (a) except that 50 g of lecithin and 100 mL of water were subjected to a hydrolysis reaction at 350 rpm for 4 hours while stirring, to prepare a crude fatty acid. The degree of splitting of the obtained fatty acid was 97.0, and the generated char was 3.8 g as a non-dry weight.

e. A hydrolysis reaction was carried out in the same manner as in Example 1 (a) except that 50 g of lecithin and 100 mL of water were subjected to hydrolysis reaction at 180 ° C and 10 bar pressure at 350 rpm for 6 hours, Crude fatty acids were prepared. The degree of splitting of the obtained fatty acid was 50.0, and no char was formed.

[Example 2] Analysis of reactants

Analysis of the separated fatty acid and by-product layer obtained in Example 1 d revealed that the content of phosphorus (P) in the raw lecithin was 18,000 ppm, but the content of phosphorus (P) in the hydrolyzed fatty acid decreased to 370 ppm, White powder was formed with char in the layer (water layer). It was phosphate which was combined with calcium (Ca), potassium (K), magnesium (Mg)

[Example 3] Production of fatty acid methyl esters

100 g of the fatty acid obtained in Example 1 d was placed in a 250 mL high-temperature / high-pressure reactor and semi-batch reaction was carried out with 16.7 g of methanol being supplied per hour. The esterification reaction was carried out while maintaining the temperature at 290 ° C and the pressure of 5 to 8 bar to prepare fatty acid methyl esters. The water from the reaction and methanol not participating in the reaction were separated by cooling in a condenser and the conversion of fatty acid methyl ester to fatty acid was measured by measuring the acid value of the reaction solution. After the esterification reaction for 6 hours, the acid value was 0.3 mg / KOH / g. After the reaction, phosphorus (P) content in the methyl ester decreased to 100 ppm.

Claims (11)

Hydrolyzing an oil containing a polar lipid to obtain a by-product comprising crude fatty acid and glycerin;
Separating the by-product comprising the crude fatty acid and glycerin produced by the hydrolysis reaction to separate the fatty acid from the by-product layer comprising glycerin and water;
Reacting the separated fatty acid with an alcohol to carry out an esterification reaction to obtain a fatty acid alkyl ester; And
And purifying the fatty acid alkyl ester to obtain a biodiesel fuel. The method of claim 1, wherein the polar lipid is selected from the group consisting of phospholipids, glycolipids, and mixtures thereof. The method of claim 1, wherein the oil comprising the polar lipid comprises 3 to 100% by weight of polar lipid and 0 to 97% by weight of neutral lipid. The method for producing biodiesel according to claim 1, wherein the oil containing the polar lipid is plant seed oil or microalgae oil obtained by squeezing plant seeds or microalgae or extracting with a solvent. The process according to claim 1, wherein the hydrolysis of the oil comprising the polar lipid is carried out by reacting an oil comprising polar lipid with water at a reaction temperature of 200 to 280 ° C and a reaction pressure of 30 to 80 bar By weight based on the total weight of the biodiesel. The method of claim 1, wherein the hydrolysis of the oil comprising the polar lipid is performed by an enzyme capable of separating the fatty acid from the lipid in the oil comprising the polar lipid. 7. The method according to claim 6, wherein the enzyme is a lipase. The method according to claim 1, wherein the step of separating the by-product containing the crude fatty acid and the glycerin is performed in a state where the degree of splitting of the fatty lipid-containing oil to fatty acid is 50 or more, Is carried out with the amount of phospholipid being reduced. The method for producing biodiesel according to claim 1, further comprising the step of purifying the fatty acid alkyl ester to obtain heavy oil. A hydrolysis reactor for hydrolyzing an oil containing a polar lipid and separating a hydrolysis reaction product to separate a byproduct layer containing glycerin and water and a crude fatty acid;
A flash tank for storing the separated crude fatty acid;
A water recovery section for separating the solid component from the by-product layer separated from the crude fatty acid by solid-liquid separation and then distilling off the water to obtain concentrated glycerin;
An esterification reactor for esterifying fatty acids and alcohols in the flash tank to produce fatty acid alkyl esters and separating water and excess alcohol from the fatty acid alkyl esters in the esterification reaction; And
And a biodiesel distillation column for separating the biodiesel by distilling the separated fatty acid alkyl ester according to the molecular weight. 11. The apparatus of claim 10, wherein the polar lipid is selected from the group consisting of phospholipids, glycolipids, and mixtures thereof.

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