KR102422678B1 - Method for producing bio oil from lignin derived from biomass using base catalyst - Google Patents

Abstract

The present invention relates to a method for producing bio-oil from lignin derived from biomass using a base catalyst, and more particularly, hydrolyzing lignin extracted from a biomass raw material in subcritical water using a base catalyst to obtain a high yield from lignin. It relates to a method for producing bio-oil from biomass-derived lignin using a base catalyst capable of efficiently extracting bio-oil, facilitating a process, and reducing manufacturing cost at the same time.

Description

Method for producing bio-oil from lignin derived from biomass using a base catalyst

The present invention relates to a method for producing bio-oil from lignin derived from biomass using a base catalyst.

As a solution to high oil prices and global warming, one of the issues in the global trend is energy that can replace oil. One of the leading alternative energy sources is biofuels. Biofuel is a generic term for energy obtained by using biomass as a raw material, and is obtained through direct combustion, alcohol fermentation, methane fermentation, and the like.

Biomass refers to the conversion of all organisms on earth, including land and water plants, animals, and microorganisms, into substances. It is a concept that encompasses the whole. Such biomass is formed based on plants, and plants are carbon compounds that store solar energy during chemical bonding, and biomass can be said to be an energy storage material composed of carbon compounds like fossil fuels.

Recently, many methods for producing bio-oil using such biomass have been proposed, and one of them is a method using a pyrolysis process. The conventional biomass rapid pyrolysis (flash pyrolysis) process can yield 70% of a liquid product, but the liquid product produced through such a rapid pyrolysis process has a limit to use without further improvement or purification.

Accordingly, the present inventors extracted lignin that can be used as a high value-added compound from biomass raw materials while researching to solve the problems of the existing method of extracting bio-oil from biomass, and using a base catalyst of a specific concentration in subcritical water. The present invention was completed by finding that a high yield of bio-oil can be obtained by hydrolyzing lignin.

Korean Patent No. 10-1725178

In order to solve the above problems, an object of the present invention is to provide a method for producing bio-oil from biomass-derived lignin in the presence of a base catalyst of a specific concentration in subcritical water.

The object of the present invention is not limited to the object mentioned above. The objects of the present invention will become more apparent from the following description, and will be realized by means and combinations thereof described in the claims.

The present invention comprises the steps of extracting lignin from a biomass raw material; hydrolyzing the lignin extracted from the biomass raw material in sub-critical water in the presence of a base catalyst to obtain a reaction product; extracting an organic phase product by adding an extraction solvent to the reaction product; And it provides a method for producing bio-oil from biomass-derived lignin using a base catalyst comprising a; and filtering after mixing the organic solvent with the organic product to obtain bio-oil.

The biomass raw material may be at least one selected from the group consisting of giant pampas grass, reeds, millet stalks, corn stalks, rice straw, kenaf, rice husks, nut shells and coconut shells.

The biomass raw material may include lignin in an amount of 10 to 35% by weight based on the total weight.

The base catalyst is sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, barium hydroxide, sodium hydroxide, iron hydroxide, lithium hydroxide, zinc hydroxide, nickel hydroxide, tin hydroxide, barium hydroxide, cobalt hydroxide, chromium hydroxide, ammonium hydroxide, It may be at least one selected from the group consisting of zirconium hydroxide, titanium hydroxide, tantalum hydroxide, hafnium hydroxide, niobium hydroxide, chromium hydroxide, vanadium hydroxide and sodium methoxide.

In the step of obtaining the reaction product, the concentration of the base catalyst may be 0.1 to 2.5 M.

Obtaining the reaction product may be hydrolyzed under a pressure of 80 to 110 bar for 20 minutes to 2 hours at a temperature of 250 ~ 350 ℃.

The extraction solvent may be at least one selected from the group consisting of ethyl acetate, acetone, propanol and ethanol.

The organic solvent may be at least one selected from the group consisting of diethyl ether, dimethyl ether, acetonitrile and cyclohexane.

The bio-oil is phenol (Phenol), 1,2-benzenediol (1,2-Benzenediol), 3-ethylphenol (3-Ethyl phenol), 4-methyl-1,2-benzenediol (4-Methyl-1) ,2-benzenediol) and 2-methoxy-phenol (2-Methoxy-phenol) may be at least one selected from the group consisting of.

The method for producing bio-oil from biomass-derived lignin according to the present invention is capable of efficiently extracting high yield of bio-oil from lignin by hydrolyzing lignin extracted from biomass raw material in subcritical water using a base catalyst of a specific concentration. can

In addition, the method for producing bio-oil from biomass-derived lignin according to the present invention increases the production efficiency of bio-oil by controlling only the concentration of the base catalyst and the hydrolysis temperature, thereby facilitating the process and reducing the manufacturing cost.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a graph showing the extraction yield results of each product obtained from lignin when the concentration of the base catalyst according to Example 1 of the present invention is varied to 0, 0.25, 0.77, 1.32, and 1.88 M, respectively.
Figure 2 is a graph showing the extraction yield results of each product obtained from lignin when the hydrolysis temperature according to Example 2 of the present invention is varied to 280, 290, 300, 310, 320 ℃, respectively.

Hereinafter, the present invention will be described in more detail by way of an embodiment.

The present invention relates to a method for producing bio-oil from lignin derived from biomass using a base catalyst.

Specifically, the present invention comprises the steps of extracting lignin from a biomass raw material; hydrolyzing the lignin extracted from the biomass raw material in sub-critical water in the presence of a base catalyst to obtain a reaction product; extracting an organic phase product by adding an extraction solvent to the reaction product; And it provides a method for producing bio-oil from biomass-derived lignin using a base catalyst comprising a; and filtering after mixing the organic solvent with the organic product to obtain bio-oil.

In the step of extracting lignin from the biomass raw material, the biomass raw material may be one or more selected from the group consisting of giant pampas grass, reed, sorghum, corn stalk, rice straw, kenaf, rice husk, nut shell, and coconut shell, but limited thereto it's not going to be The biomass raw material may be preferably giant pampas grass, kenaf or a mixture thereof, and most preferably giant pampas grass. The biomass raw material may contain 10 to 35% by weight, preferably 15 to 30% by weight, and most preferably 28% by weight of lignin based on the total weight.

In the obtaining of the reaction product, the reaction product may be obtained by hydrolyzing the lignin in sub-critical water in the presence of a base catalyst. In the subcritical water, when water is heated to 100° C. or higher, the dielectric constant decreases and ion products increase, and the dielectric constant of water at 200° C. becomes the same as that of methanol at room temperature. And at 297 ° C, benzene is completely miscible with water, and can act as a catalyst because H ₃ O ⁺ and OH ⁻ ion concentrations are several orders of magnitude higher than that of water. The subcritical water has excellent hydrolysis power and organic substance dissolving power, so it is possible to increase the extraction yield of useful components from raw materials, and has an economical advantage compared to the conventional thermal decomposition method or solvent extraction method. In addition, the base catalyst serves to facilitate the depolymerization of the lignin, and as a result, it is possible to extract the bio-oil in a high yield from the lignin.

That is, in the obtaining of the reaction product, only when both the subcritical water phase and the base catalyst conditions are satisfied, the reaction product containing the bio-oil, an useful component contained in the lignin, can be obtained to the maximum. In particular, if both the conditions of the subcritical phase and the base catalyst are not satisfied when obtaining the reaction product, the depolymerization of the lignin does not occur properly, so that the extraction yield of the bio-oil is remarkably reduced, and there is a problem that the extraction time is long.

The base catalyst is sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, barium hydroxide, sodium hydroxide, iron hydroxide, lithium hydroxide, zinc hydroxide, nickel hydroxide, tin hydroxide, barium hydroxide, cobalt hydroxide, chromium hydroxide, ammonium hydroxide, It may be at least one selected from the group consisting of zirconium hydroxide, titanium hydroxide, tantalum hydroxide, hafnium hydroxide, niobium hydroxide, chromium hydroxide, vanadium hydroxide and sodium methoxide. Preferably, the base catalyst may be at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide, and most preferably sodium hydroxide.

The base catalyst may have a concentration of 0.1 to 2.5 M, preferably 0.15 to 2.2 M, more preferably 0.25 to 2 M, even more preferably 0.75 to 1.9 M, and most preferably 1.3 M. At this time, if the concentration of the base catalyst is less than 0.1 M, it is difficult to obtain a reaction product having a high content of useful components from the lignin, and on the contrary, if the concentration is more than 2.5 M, the reaction containing a high content of useful components from the lignin is no longer There is a limit to obtaining a product.

The method may further include lowering the pH of the reaction product to 1-2 by adding an acid catalyst to the reaction product between obtaining the reaction product and extracting the organic phase product. When the pH of the reaction product is lowered to the above range, free radicals present in the reaction product can be effectively removed. The free radical is an independently existing chemical species having unshared unpaired electrons, and since the reactivity is very high, the stability of the reaction product may be lowered, and as a result, the extraction of the organic phase product may be hindered. The acid catalyst may be at least one selected from the group consisting of sulfuric acid, malic acid, hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, formic acid, acetic acid, hydrofluoric acid, oxalic acid and citric acid, but is not limited thereto.

In the step of extracting the organic phase product, an extraction solvent may be added to the reaction product and the organic phase product and biochar may be separated and extracted by liquid-liquid extraction. In this case, the biochar refers to a solid material having a high carbon content produced when biomass is pyrolyzed under oxygen-limited conditions.

The extraction solvent may be at least one selected from the group consisting of ethyl acetate, acetone, propanol and ethanol, and preferably ethyl acetate may be used.

After extracting the organic product, the organic product may be distilled under reduced pressure to remove an extraction solvent that may remain in the product.

In the step of obtaining the bio-oil, the bio-oil may be obtained by mixing the organic product with an organic solvent and filtering using a filter. The organic solvent may be at least one selected from the group consisting of diethyl ether, dimethyl ether, acetonitrile and cyclohexane. Preferably, the organic solvent may be diethyl ether, dimethyl ether, or a mixture thereof, and most preferably diethyl ether.

The bio-oil is phenol (Phenol), 1,2-benzenediol (1,2-Benzenediol), 3-ethylphenol (3-Ethyl phenol), 4-methyl-1,2-benzenediol (4-Methyl-1) ,2-benzenediol) and 2-methoxy-phenol (2-Methoxy-phenol) may be at least one selected from the group consisting of. Preferably, the bio-oil may be a mixture of phenol, 1,2-benzenediol, 3-ethylphenol, 4-methyl-1,2-benzenediol, and 2-methoxy-phenol.

As described above, in the method for producing bio-oil from biomass-derived lignin according to the present invention, high yield of bio-oil is efficiently extracted from lignin by hydrolyzing lignin extracted from biomass raw material in subcritical water using a base catalyst. can do. In addition, the present invention can facilitate the process and reduce the manufacturing cost by increasing the production efficiency of bio-oil by adjusting only the concentration of the base catalyst and the hydrolysis temperature.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1: Evaluation of the extraction yield of bio-oil according to the change in the concentration of the base catalyst

Lignin was extracted by a conventional method using giant pampas grass, a biomass raw material. Then, 6 g of the extracted lignin and an aqueous NaOH solution as a base catalyst were put into a 200 ml reactor (200 ml Auto Clave Reactor System) and hydrolyzed in subcritical water at a temperature of 300 ° C. for 30 minutes under a pressure of 90 bar to obtain a reaction product. At this time, the concentration of the NaOH aqueous solution was changed to 0, 0.25, 0.77, 1.32, 1.88 M, respectively, to obtain a reaction product. Each of the obtained reaction products was lowered to a pH of 1 by adding hydrochloric acid (HCl). Then, after adding ethyl acetate as an extraction solvent to each reaction product, the organic phase product and biochar, Coke, were separated using a conventional liquid-liquid extraction method. The organic product was distilled under reduced pressure to completely remove ethyl acetate. The organic product thus obtained was dissolved in diethyl ether as an organic solvent, and then residual lignin and light oil as bio-oil were obtained by using a filter. The yield of each product obtained from the lignin was calculated using the following formula. The results are shown in Table 1 and FIG. 1 below. 1 is a graph showing the extraction yield results of each product obtained from lignin when the concentration of the base catalyst according to Example 1 was changed to 0, 0.25, 0.77, 1.32, and 1.88 M, respectively.

[Yield formula]

Yield (%) of light oil = light oil content / total lignin content x 100

Yield (%) of residual lignin = residual lignin content / total lignin content x 100

Yield (%) of bio tea (Coke) = bio tea content / total lignin content x 100

Referring to Table 1 and FIG. 1, it was confirmed that the extraction yield of bio-oil was the highest at about 43.19% when the concentration of the aqueous NaOH solution serving as the base catalyst was 1.32 M. This showed a difference of about 2 times or more compared to the case of extraction without the addition of a base catalyst at all. Through this, it was found that the base catalyst helps the depolymerization of lignin to occur well. In addition, in the case of biochar (Coke) and residual lignin, it was confirmed that the higher the concentration of the base catalyst, the lower the yield.

Example 2: Evaluation of extraction yield of bio-oil according to hydrolysis temperature change

Lignin was extracted by a conventional method using giant pampas grass, a biomass raw material. Then, 6 g of extracted lignin and 1.32 M aqueous NaOH solution as a base catalyst were put into a 200 ml reactor (200 ml Auto Clave Reactor System), and the hydrolysis temperature was changed to 280, 290, 300, 310, and 320 ° C in subcritical water for 30 minutes. During the hydrolysis reaction under a pressure of 90 bar, a reaction product was obtained. At this time, the obtained reaction product was lowered to pH 1 by adding hydrochloric acid (HCl). Then, ethyl acetate was added to the reaction product as an extraction solvent, and the organic phase product and biochar (Coke) were separated using a conventional liquid-liquid extraction method. The organic product was distilled under reduced pressure to completely remove ethyl acetate. The organic product thus obtained was dissolved in diethyl ether as an organic solvent, and then residual lignin and light oil as bio-oil were obtained by using a filter. The calculation of the yield of each product obtained from the lignin was carried out using the same formula as in Example 1. The results are shown in Table 2 and FIG. 2 below. 2 is a graph showing the extraction yield results of each product obtained from lignin when the hydrolysis temperature according to Example 2 was changed to 280, 290, 300, 310, and 320 °C, respectively.

Referring to Table 2 and Figure 2, it was confirmed that the extraction yield of the bio-oil is the highest when the hydrolysis temperature is 300 ℃. In addition, it was found that the yield of residual lignin and bio-char (Coke) showed a tendency to gradually decrease as the hydrolysis temperature and the yield of bio-oil increased. Through this, it was found that when the concentration of the aqueous solution of NaOH, which is the base catalyst, was 1.32 M and the temperature of hydrolysis was 300 ° C, the bio-oil could be extracted from lignin to the maximum.

In particular, as a result of analyzing the composition of the bio-oil obtained at a hydrolysis temperature of 300 ° C and a NaOH concentration of 1.32 M, phenol (Phenol), 1,2-benzenediol (1,2-Benzenediol) as main components, 3-Ethyl phenol, 4-methyl-1,2-benzenediol, and 2-methoxy-phenol (2-Methoxy-phenol) were obtained.

Claims (9)

extracting lignin from biomass raw material consisting of giant pampas grass;
hydrolyzing the lignin extracted from the biomass raw material in sub-critical water in the presence of a base catalyst to obtain a reaction product;
extracting an organic phase product by adding an extraction solvent to the reaction product; and
mixing the organic product with an organic solvent and filtering to obtain a bio-oil;
including,
In the step of obtaining the reaction product, the base catalyst is sodium hydroxide having a concentration of 1.32 M,
The step of obtaining the reaction product is hydrolysis under a pressure of 90 bar at a temperature of 300 ° C. for 30 minutes,
The extraction solvent is ethyl acetate,
A method for producing bio-oil from biomass-derived lignin using a base catalyst that the extraction yield of the bio-oil is 43.19%.
delete According to claim 1,
The method for producing bio-oil from biomass-derived lignin using a base catalyst, wherein the biomass raw material contains lignin in an amount of 10 to 35% by weight based on the total weight.
delete delete delete delete According to claim 1,
The organic solvent is at least one selected from the group consisting of diethyl ether, dimethyl ether, acetonitrile and cyclohexane. A method for producing bio-oil from biomass-derived lignin using a base catalyst.
According to claim 1,
The bio-oil is phenol (Phenol), 1,2-benzenediol (1,2-Benzenediol), 3-ethylphenol (3-Ethyl phenol), 4-methyl-1,2-benzenediol (4-Methyl-1) ,2-benzenediol) and 2-methoxy-phenol (2-Methoxy-phenol) A method for producing bio-oil from biomass-derived lignin using a base catalyst that is at least one selected from the group consisting of.

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