KR101300677B1 - Method for preparing enzymatic biodiesel using semi-continuous under near critical CO2 and the device thereof - Google Patents

Abstract

The biodiesel manufacturing method and the biodiesel manufacturing apparatus according to the present invention are inventions which significantly shorten the production time of biodiesel by repeatedly using a predetermined process. Specifically, the invention relates to a process of separating and storing liquid carbon dioxide, biodiesel, glycerol and residual substances, and repeatedly carrying out these steps. Thus, if biodiesel is produced according to the present invention, even if biodiesel is produced using liquid carbon dioxide having a slow diffusion rate compared to supercritical carbon dioxide, the production time can be significantly shortened. In addition, residual materials from the biodiesel production process can be reused continuously, making the environment more eco-friendly and economical and significantly lowering production costs.

Description

Method for preparing enzymatic biodiesel in subcritical carbon dioxide and its manufacturing apparatus {Method for preparing enzymatic biodiesel using semi-continuous under near critical CO2 and the device

The present invention relates to an enzymatic biodiesel production method and an apparatus for producing the same.

Biodiesel is a fuel made from animal and vegetable fats and oils. Similar to diesel, biodiesel does not require modification of diesel engines, and can utilize existing gas station infrastructure as well as air pollution caused by the use of existing fossil energy. And it is attracting much attention as an alternative energy in that it brings about an environmental improvement effect of reducing greenhouse gas.

The chemical name of biodiesel is Fatty Acid Methyl Ester (FAME), which is prepared by transesterification of alcohol with Triglyceride (TG) extracted from animal and vegetable fats and oils.

In the preparation of such biodiesel, a method using a conventional enzyme has been developed. However, methanol used as an organic solvent acts as an inhibitor and reduces the reaction efficiency.

Thus, to solve this problem, a method of preparing biodiesel using lipase as an enzyme and supercritical carbon dioxide as an environmentally friendly solvent has been developed. However, even in this case, there is a problem that the solubility of the oil used as the substrate for the supercritical carbon dioxide is not high, and the disadvantages of high energy consumption to maintain the supercritical state and the problem of generating insoluble methanol that inhibit the activity of the enzyme there was.

To solve this problem, a method of using liquid carbon dioxide instead of supercritical carbon dioxide has been developed. However, until now, no process for continuously producing enzymatic biodiesel using liquid carbon dioxide has been proposed, and in the case of using liquid carbon dioxide, the production time may be too long due to the difference in diffusion rate compared to the case of applying supercritical carbon dioxide. Possible problems may arise.

In order to solve the problems of the prior art as described above, while using the liquid carbon dioxide it is to significantly shorten the production time and to provide a semi-continuous biodiesel manufacturing method and biodiesel manufacturing apparatus.

In the biodiesel manufacturing method according to the present invention, oil and carbon dioxide are supplied through a carbon dioxide supply line connected to an oil supply pipe for supplying oil to a biocatalyst reactor, and methanol is supplied through a methanol supply line, and the first separator is used to supply the biodiesel. Separating the biodiesel from the carbon dioxide by receiving a mixture including carbon dioxide, glycerol and residual materials together with the biodiesel produced after biodiesel synthesis from the biocatalytic reactor connected to the catalytic reactor and the first mixture supply line; Separating the glycerol from the biodiesel and carbon dioxide-free mixture from the first separator by a separator connected to a second mixture supply line;

 The second separator and the third mixture supply line is connected to a mixer to supply a mixture and a metalol from which the glycerol has been removed from the second separator to mix and then supply the mixture to the oil supply line. Includes repeated In addition, the carbon dioxide introduced into the biocatalyst reactor includes liquid carbon dioxide. In addition, the separated carbon dioxide may be stored in a storage tank and then cooled and reused.

In addition, the biocatalyst reactor is characterized in that the lipase is fixed.

In addition, the reaction conditions of the biocatalyst reactor includes a reaction temperature of 20 to 30 ℃, reaction pressure of 60 to 120 bar, the stirring speed of 100 to 500rpm.

In addition, the molar ratio of the methanol and oil supplied to the biocatalyst reactor includes 2.8-3.2: 0.8-1.2.

According to another aspect of the present invention, a biodiesel manufacturing apparatus includes a carbon dioxide supply line in which gaseous carbon dioxide is cooled through a cooler and supplied as a liquid phase, an oil supply line in which oil is supplied, a methanol supply line in which methanol is supplied, and the carbon dioxide supply. A biocatalyst reactor in which materials are supplied from the line, the oil supply line, and the methanol supply line to react, and a first separator in which the reacted material moves from the biocatalytic reactor to be separated into carbon dioxide, biodiesel, and the rest of the material. A second separator in which the remaining material separated in the first separator is moved to separate glycerol and the remaining material, and a mixer in which the remaining material separated from the second separator is moved and mixed with methanol supplied from the methanol supply line. including And repeating the cycle of the material composed and mixed with the methanol passed through the mixer is fed back to the biocatalyst reactor.

In addition, the carbon dioxide separated from the first separator is stored in the storage tank, it characterized in that the cooler is moved to reuse.

In addition, the biocatalyst reactor is characterized in that the lipase is fixed.

In addition, the reaction conditions of the biocatalyst reactor includes a reaction temperature of 20 to 30 ℃, reaction pressure of 60 to 120 bar, the stirring speed of 100 to 500rpm.

In addition, the molar ratio of the methanol and oil supplied to the biocatalyst reactor is characterized in that the 2.8 ~ 3.2: 0.8 ~ 1.2.

Biodiesel according to another feature of the invention is characterized in that it is produced by the biodiesel manufacturing method.

Biodiesel according to another feature of the invention is characterized in that produced by the biodiesel manufacturing apparatus.

The biodiesel manufacturing method and the biodiesel manufacturing apparatus according to the present invention can repeatedly shorten the production time even if biodiesel is produced using liquid carbon dioxide having a slow diffusion rate compared to supercritical carbon dioxide. It is an invention about the thing. In addition, the present invention relates to more environmentally friendly, economical, and significantly lower production costs, since the residual materials and enzymes released from the biodiesel production process can be continuously reused.

1 is a view showing a biodiesel manufacturing process according to the present invention.
2 is a diagram illustrating a case where the process is repeated three times.
3 is a view showing a biodiesel manufacturing process according to Comparative Example 1.
4 is a view showing a biodiesel manufacturing process according to Comparative Example 2.
5 is a graph showing the biodiesel conversion rate with time change in the case of Example, Comparative Example 1, and Comparative Example 2. FIG.
FIG. 6 is a graph measuring the activity of Lipozyme TL IM according to the change of time in the case of Example, Comparative Example 1, and Comparative Example 2 in consideration of biodiesel conversion.

The present inventors have made a thorough research effort to overcome the problems of the prior art, and as a result, the biodiesel production method and the biodiesel production apparatus have been completed. In other words, if the biodiesel using liquid carbon dioxide is manufactured by repeating a certain process according to the present invention, or the biodiesel is manufactured using a device in which a certain process is repeated, the production time is remarkably shortened and the present invention has been completed. .

Specifically, in the manufacturing method for producing biodiesel using a device including a liquid carbon dioxide and a device including a cooler, a surge tank, a biocatalaytic reactor, and a biodiesel storage tank, the process according to the present invention comprises a surge tank. The liquid carbon dioxide passed through is introduced into a biocatalaytic reactor. The liquid carbon dioxide introduced into the biocatalaytic reactor is mixed with methanol and oil. At this time, the molar ratio of the added methanol and oil is preferably 2.8-3.2: 0.8-1.2. An enzyme is immobilized in such a biocatalaytic reactor. It is preferable to use a lipase as an immobilized enzyme used in the production of enzymatic biodiesel using such liquid carbon dioxide. It is preferable to use. Also the most preferred lipase is Lipozyme TL IM with the highest conversion rate. The lipase is preferably added in 5 to 30 parts by weight based on 100 parts by weight of oil.

The biocatalaytic reactor is a transesterification reaction for producing biodiesel. At this time, the reaction temperature is 20 ~ 30 ℃, the reaction pressure is 60 ~ 120bar, the stirring speed of the reactor is preferably made of 100 ~ 500rpm.

The biodiesel synthesized through the biocatalyst reactor and the residual material including liquid carbon dioxide and glycerol are added to the first separator. The biodiesel synthesized through this first separator is moved to and stored in the biodiesel storage tank, and the liquid carbon dioxide is moved to and stored in the liquid carbon dioxide storage tank. The stored liquid carbon dioxide is moved back to the cooler and reused. Residues, including glycerol, are also transferred to the second separator. Thus, glycerol is transferred to and stored in a glycerol storage tank through a second separator. The residual material separated from glycerol through the second separator is mixed with methanol through a mixer, and the mixture is fed into the biocatalyst reactor to be reused in this biodiesel synthesis step. In addition, oil and fresh liquid carbon dioxide are fed back before the mixture passed through the mixer is introduced into the biocatalyst reactor. And the biodiesel is synthesized by repeating the above process. This process is also referred to by the inventors as RMGS step for convenience.

In addition, the biodiesel manufacturing apparatus according to the present invention specifically comprises a carbon dioxide supply line, an oil supply line, a methanol supply line, a biocatalyst reactor, a first separator, a second separator, and a mixer.

The carbon dioxide supply line is characterized in that the gaseous carbon dioxide is cooled through a cooler and supplied as a liquid phase. In addition, the oil supply line is characterized in that the oil is supplied. In addition, the methanol supply line is characterized in that the methanol is supplied. In addition, the biocatalyst reactor is characterized in that the reaction occurs by supplying materials from the carbon dioxide supply line, the oil supply line, the methanol supply line. In addition, the first separator is characterized in that the reaction material is moved from the biocatalyst reactor is separated into carbon dioxide, biodiesel, and the remaining material. In addition, the second separator is characterized in that the remaining material separated in the first separator is moved back to separate the glycerol and the remaining material. In addition, the mixer is characterized in that the remaining material separated from the second separator is moved and mixed with methanol supplied from the methanol supply line. In addition, the biodiesel manufacturing apparatus according to the present invention is characterized by repeating a cycle in which the material mixed with methanol passing through the mixer is introduced into the biocatalyst reactor again.

The molar ratio of oil and methanol supplied through the oil supply line and the methanol supply line is preferably 2.8-3.2: 0.8: 1.2. In addition, an enzyme is immobilized in the biocatalyst reactor, preferably a lipase is immobilized. In addition, as the lipase, it is preferable to use one or two or more selected lipases from the group consisting of Novozzy 435, Lipozyme RM-IM and Lipozyme TL IM. In addition, the lipase is preferably added in 5 to 30 parts by weight based on 100 parts by weight of oil. The biocatalaytic reactor is also transesterified to produce biodiesel. At this time, the reaction temperature is 20 ~ 30 ℃, the reaction pressure is 60 ~ 120bar, the stirring speed of the reactor is preferably made of 100 ~ 500rpm. In addition, the carbon dioxide separated through the first separator is stored in the carbon dioxide storage tank and moved to the cooler is characterized in that for reuse. In addition, the biodiesel separated in the first separator is stored in a biodiesel storage tank, and the glycerol separated in the second separator is stored in a glycerol storage tank.

The biodiesel manufacturing method and the biodiesel manufacturing apparatus including the process (RMGS stage) and the apparatus are shown in FIG. 1, and an example of the process (RMGS stage) repeated three times is shown in FIG. 2.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example

Purified canola oil and soybean oil were purchased from CJ. Waste processed oil was collected from a restaurant in Cheonan and jatropha oil was provided from a local Jatropha farm in India. The following enzymes were supplied from Novozymes A / S (Bagsberg, Denmark): Candida Anne produced from submerged fermentation of Novozym 435 (systemically modified Aspergillus oryzae) and immobilized on porous acrylic resin. Candida antarctica lipase, specific activity against hydrolysis, 10,000 PLU / g); Lipozyme RM IM (Rhizomucor miehei lipase immobilized on anion exchange resin; particularly active against hydrolysis of tributylene, 40 U / g); Lipozyme TL IM (acrylic saengse immobilized Thermomyces lanuginosus lipase, specific activity for hydrolysis of tributyrin, 20,000 U / g).

Methanol was supplied from Fisher and FAME (fatty acid methyl ester) standard (RM-3) was purchased from Supelco (Bellefonte, PA, USA).

The reactant loop was filled with 0.05 mole of canola oil and methanol solvent so that methanol was added sequentially into the biodiesel synthesis process according to the present invention. The reaction was fed into a biocatalyst reactor loaded with the enzyme Lipozyme TL IM immobilized with liquid carbon dioxide and the first pressure was adjusted to 100 bar. In addition, the temperature in a reactor was 30 degreeC and the stirring speed of the reactor was adjusted to 100 rpm. The immobilized enzyme Lipozyme TL IM was maintained using a filtration system in a biocatalyst reactor.

Thereafter, 44.3 g of canola oil and 6.1 mL of methanol were fed to the biocatalyst reactor by a liquid pump. Each of these canola oil and methanol was fed into the biocatalytic reactor by 0.05 mol of liquid pump, respectively, and after the reaction, the pressure was reduced by the release of carbon dioxide.

The resulting mixture was extracted from the reactor, the liquid carbon dioxide was stored in the liquid carbon dioxide storage tank through the first separator, and the stored liquid carbon dioxide was moved back to the cooler for reuse. The synthesized biodiesel was also stored in biodiesel storage tanks. Residual material, including glycerol, was also transferred to the second separator. Glycerol was transferred to and stored in a glycerol storage tank through a second separator. The residue passed through the second separator was mixed with 0.05 mol of methanol by a mixer. Residue and methanol passed through the mixer are then introduced into the biocatalyst reactor with 44.3 g of fresh liquid carbon dioxide and 0.05 mol of canola oil. Thus the process was repeated again.

Comparative Example  One

This comparative example is a biodiesel synthesis method comprising a carbon dioxide injector, a cooler, a liquid pump, a surge tank, a biocatalytic reactor, and a biodiesel storage tank (FIG. 3).

Comparative Example  2

Including a separator for separating the liquid carbon dioxide used in Comparative Example 1, and comprises a loop for reusing the carbon dioxide separated. In addition, the biodiesel synthesis method according to Comparative Example 1 is a biodiesel synthesis method comprising a configuration in which methanol and oil are separately supplied (FIG. 4).

Experimental Example

< Experimental Example  One: Examples and Comparative Example  1 and Comparative Example  According to 2 Conversion rate  And synthesis time comparison experiments>

Experiments were carried out to determine the biodiesel conversion and synthesis time according to Examples and Comparative Examples 1 and 2 according to the present invention. The experiment was conducted through a semi-continuous reactor in which three reactors of FIG. 2 were connected in series. The result is shown in FIG. 5.

First, as shown in FIG. 5, the maximum biodiesel conversion of Comparative Example 1 was 99.0% after 9 hours. The progress of the reaction showed rapid conversion for up to 3 hours, followed by slower reaction phases. This seems to be the result of the enzyme being exposed to excess alcohol solvent.

Also in Comparative Example 2, the initial reaction rate was increased and the biodiesel conversion reached 86% within 3 hours. However, in the case of applying the repeating batch according to the present invention, the biodiesel conversion rate was higher as 96.8%, and it could be confirmed that the synthesis time required until this was only 3 hours. In addition, when the biodiesel is manufactured using the repeated batch process according to the present invention, the manufacturing time was remarkably shortened.

< Experimental Example  2: Experiment of Maintaining Enzyme Activity in Repeated Batch Process>

This experiment is to test how long the Lipozyme TL IM used as an enzyme immobilized in the biocatalyst reactor in Example and Comparative Example 1 and Comparative Example 2 can stably maintain the activity. This experiment was conducted through a semi-continuous reactor in which three reactors of FIG. 2 were connected in series, and the results are shown in FIG. 6.

As shown in FIG. 6, it was confirmed that 80.2% of initial activity was maintained even after the Lipozyme TL IM was reused 8 times as in the present example. This is solved by the fact that methanol, which is an alcohol solvent, is gradually added without a high concentration from the beginning, and an effect of removing glycerol which can act as an inhibitor of enzyme activity. Therefore, even if the enzyme is reused through a repeated batch process as in the embodiment according to the present invention, its activity and stability are maintained. Therefore, the present invention is to produce biodiesel with enzyme activity maintained even though the synthesis of enzymatic biodiesel using liquid carbon dioxide is repeated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It is natural.

1.CO2 injector
2.cooler
3.liquid pump
4.surge tank
5. Oil supply line
6. Biocatalytic Reactor
7. The first separator
8. Biodiesel Storage Tank
9.glycerol storage tank
10.Second separator
11.Liquid Pump
12.Mixer
13. Carbon dioxide supply line
14. First Mixture Supply Line
15. Methanol Supply Line
16. Second Mixture Supply Line
17. Third mixture supply line
18.CO2 storage tank
19.Carbon dioxide reuse supply line
20.RMGS Step
21.Oil and Methanol Supply Line

Claims (14)

(a) supplying oil and carbon dioxide through a carbon dioxide supply line connected to an oil supply pipe for supplying oil to the biocatalyst reactor, and supplying methanol through a methanol supply line;
(b) a first separator is connected to the biocatalyst reactor and the first mixture feed line to receive a mixture containing carbon dioxide, glycerol and residues together with biodiesel produced after biodiesel synthesis from the biocatalytic reactor; Separating from the mixture a mixture comprising glycerol from which biodiesel and carbon dioxide has been removed and a residue;
(c) a second separator is connected to a second mixture supply line to receive a mixture comprising the glycerol and the residue from the first separator to separate the glycerol and the residue, respectively; And
(d) connecting the second separator and the third mixture supply line to a mixer to receive and mix the separated residue and the metalol from the second separator, and then supply the mixture to the oil supply line;
Carbon dioxide introduced into the biocatalyst reactor is liquid carbon dioxide,
Reaction conditions of the biocatalyst reactor, the production of biodiesel comprising a reaction temperature of 20 ~ 30 ℃, reaction pressure 60 ~ 120bar, the stirring speed of 100 ~ 500rpm
Way.
The method of claim 1,
Biodiesel manufacturing method comprising the steps (a) to (d) is repeated.
delete The method of claim 1,
The separated carbon dioxide is stored in a storage tank biodiesel manufacturing method comprising the cooling and reuse.
The method of claim 1,
Biodiesel manufacturing method characterized in that the lipase is fixed to the biocatalyst reactor.
delete The method of claim 1,
The molar ratio of the methanol and oil is supplied to the biocatalyst reactor is 2.8 ~ 3.2: 0.8 ~ 1.2 bio-diesel manufacturing method comprising a.
A carbon dioxide supply line in which gaseous carbon dioxide is cooled by a cooler and supplied as a liquid phase;
An oil supply line through which oil is supplied;
A methanol supply line supplied with methanol;
A biocatalyst reactor in which substances are supplied from the carbon dioxide supply line, the oil supply line, and the methanol supply line to cause a reaction;
A first separator in which the reacted material moves from the biocatalyst reactor and separated into carbon dioxide, biodiesel, and the remaining material;
A second separator in which the remaining material separated in the first separator is moved and separated into glycerol and the remaining material again;
A mixer in which the remaining material separated from the second separator is moved and mixed with methanol supplied from the methanol feed line;
Repeating the cycle of introducing the mixed material with the methanol passed through the mixer to the biocatalyst reactor,
Reaction conditions of the biocatalyst reactor, the reaction temperature 20 ~ 30 ℃, reaction pressure 60 ~ 120bar, the stirring speed is made of 100 ~ 500rpm,
The molar ratio of the methanol and oil supplied to the biocatalyst reactor is 2.8 ~ 3.2: 0.8 ~ 1.2 bio-diesel production apparatus characterized in that.
The method of claim 8,
The carbon dioxide separated from the first separator is stored in a storage tank and moved to the cooler, characterized in that the bio-diesel manufacturing apparatus.
The method of claim 8,
Biodiesel production apparatus characterized in that the lipase is fixed to the biocatalyst reactor.
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