WO2015046736A1 - Method for directly producing high-energy biodiesel from wet biomass - Google Patents

Abstract

The present invention relates to a method for directly producing biodiesel from wet biomass by performing alcohol pretreatment and applying alcohol, catalyst, and heat to the pretreated biomass, without a separate lipid extraction procedure. The method of the present invention is more cost-effective than existing methods by not employing a lipid separation process, and improved the processes so that the waste generated during the processing process can be recycled, and thus an eco-friendly effect may be expected.

Description

Direct production of high energy biodiesel from wet biomass

The present invention relates to a method for the direct production of high energy biodiesel from a wet biomass, and more particularly, the step of pretreatment by adding alcohol to the wet biomass; And adding alcohol and a catalyst to the pretreated biomass, followed by heating to perform transesterification, thereby directly producing biodiesel from the wet biomass without extracting lipids. It is about.

Due to the energy consumption of developing countries, which are two to three times higher than the world average energy consumption, energy demand continues to increase rapidly around the world. According to the EIA's 2007 report, energy demand is expected to be 60% higher by 2030 than it is today.

Sustainable consumption of fossil fuels as a major source of energy is widely recognized as an unsustainable energy source because it contributes to the depletion of limited resources and contributes to global warming and environmental pollution by increasing the amount of carbon dioxide in the air in proportion to consumption. . Therefore, fossil fuels as energy sources should be replaced with ideal alternative energy sources that meet the following requirements: carbon neutral, energy neutral, sustainable and economic.

In the last decade, the scientific community has been interested in the production of biodiesel, one of the main forms of alternative energy. Almost all of today's biodiesel is produced from edible crops such as wheat and corn, waste cooking oil and animal fats. However, it is recognized that these will not serve as alternative energy sources for fossil fuels because of ultimate sustainability issues. As discussed in Daemon's research paper (Deamon, 2007, Nature, 449: 652-655) and Laurent's research paper (Laurent et al., 2009, Environ. Sci. Technol. 43: 6475-6481), The debate over fuel has been raised and the need for a biomass base that does not hinder food production. In addition, the 2011 study paper (D.H.Lee et al., 2011, Biores.Technol. 102: 43-49) raised the issue of the lack of arable land and replacement sites for biomass grown for fuel production.

Microalgae are single-cell photosynthetic organisms capable of photosynthetic growth using water, carbon dioxide and sunlight, also called phytoplankton, and are estimated to be present in about 200,000 to 800,000 species worldwide. Microalgae can be cultivated anywhere in the wasteland, the coast, and the sea as long as photosynthesis is possible.The microalgae live in freshwater or seawater, absorb carbon dioxide and release oxygen, and contain useful substances such as oil. . In particular, microalgae accumulate high quality vegetable oils in vivo through photosynthesis, and the amount of oil produced per unit area is 10 times less than conventional edible crops such as soybeans and corn for obtaining biodiesel raw oil. It is about 50-100 times higher on average. In addition, the microalgae has the advantage that the growth rate is faster than the land plants, can be grown in high concentration in a large amount, and can grow even in extreme environments. Microalgae show higher fuel productivity compared to conventional crops because the available oil content amounts to 30-70% of the biomass. In addition, since microalgae do not compete with other crops in terms of land or space, the present invention has the advantage of not causing secondary environmental problems such as rising prices of food resources and deforestation.

However, algal biodiesel, despite its high potential, uses extremely high process costs of dehydration, drying, extraction and processing when microalgae are used for biodiesel production. Microalgae also have polar structures such as monoglycerides (MAGs, monoglycerides), diglycerides (DAGs, diglycerides) and triglycerides (TAGs, triglycerides), and polar structures such as phospholipids and glycolipids. Having lipids, the biochemical composition and amount of such lipids can be altered by harvesting, drying and storage techniques. Most microalgae are known to consume stored fat through cellular respiration during long-term storage after harvesting, and contain lipases that can break down lipids into free fatty acids, resulting in significant amounts of lipids during storage at room temperature. There is a problem that the amount is lost and the quality is reduced. Thus, for this reason, it is essential that the microalgae's wet biomass be treated as soon as it is available.

Traditionally, wet biomass is dried after harvesting and the lipids are first extracted before being converted to fuel. For lipid extraction, the cell walls of microalgae composed of coarse cellulose must be destroyed. Lipids can then be recovered from the microalgae by physical (cold press, French press, homogenization and cavity methods) and chemical (solvent extraction) methods. Solvent extraction processes for lipids are generally carried out using other combinations of chlorine or neutral solvents such as chloroform, methanol and water, and after extraction, the neutral lipids can be obtained via hexane fractions. Since most individual methods are not sufficient for high recovery of lipids, a combination of these methods is required for effective extraction. However, all of the drying and extraction steps are energy intensive, expensive, use many solvents and require several steps.

There is yet no published cost effective process for the production of fatty acid esters from wet biomass of microalgae, yeast or bacteria. The present invention seeks to overcome all of these basic limitations and to develop a new, simplified, cost-effective process for producing fatty acid esters in wet biomass. In addition, several other related improvements in the process, such as the use of spent waste, in particular wastes such as hydrolyzed biomass, which can be utilized as fertilizers for the production of organic nutrients of microbial fermentation or ethanol, also form part of the invention. do.

Meanwhile, Korean Patent Publication No. 2013-0037516 discloses an 'integrated non-catalyst continuous biodiesel conversion process without omission of milking and extraction', and Korean Patent No. 1264543 discloses 'raw material for biodiesel from microalgae'. Method of extracting and biodiesel production using the same 'is disclosed, but there is no description of the direct production process of high-energy biodiesel from the wet biomass of the present invention.

The present invention is derived by the above requirements, the present inventors pre-treatment with alcohol to the microalgae with high moisture content, without additional lipid extraction process, the alcohol and catalyst to the pre-treated microalgae again and heat The present invention was completed by developing a method for producing fatty acid ethyl ester, which is a high-energy biodiesel, by adding a transesterification reaction.

In order to solve the above problems, the present invention

Pretreatment by adding alcohol to the wet biomass; And

It provides a method for producing biodiesel directly from the wet biomass without extracting lipids, comprising the step of adding an alcohol and a catalyst to the pre-treated biomass, followed by heating to perform a transesterification reaction. .

The present invention relates to a manufacturing method for producing biodiesel directly from a biomass having a high moisture content, and the method of the present invention can be effectively applied to produce high energy biodiesel without using a separate milking and extraction process using microalgae. Can be. In addition, the method of the present invention is more cost-effective than conventional methods because there is no lipid extraction process, and solvents such as chloroform, dichloromethane and carbon tetrachloride for separating lipids are not used, and wastes generated during the process can be reused. As it is an improved process, eco-friendly effects can be expected.

1 is a process chart of the production method for producing biodiesel directly from the microalgae of the present invention.

Figure 2 is a result of comparing the production of biodiesel (FAEE) according to the treatment time of alcohol pretreatment conditions. FAEE; fatty acid ethyl ester

Figure 3 is a result of comparing the production amount of biodiesel by the number of alcohol pretreatment treatment.

Figure 4 is a result of comparing the production of biodiesel according to the alcohol volume ratio to the biomass of alcohol pretreatment conditions.

5 is a result of comparing the biodiesel production according to the reaction time of the transesterification reaction.

Figure 6 is a result of comparing the biodiesel production by temperature during the transesterification reaction.

7 is a result of comparing biodiesel production according to the amount of sulfuric acid which is a catalyst used in the transesterification reaction.

8 is a result of comparing biodiesel production according to the amount of Amberlyst, a catalyst used in the transesterification reaction.

9 is a result of comparing the biodiesel production according to the reaction time of the transesterification reaction using the Amberlyst catalyst.

Figure 10 is the result of confirming the distribution of lipids in algae during the process of the present invention in three types of microalgae Atria, Nannochloropsis and Oranthiochitrium. Lipid in residual biomass; Biomass, alcohol fraction (pretreatment) remaining after conversion; Alcohol recovered after pretreatment of wet biomass, Alcohol fraction (conversion); Alcohol fractions having undergone transesterification using biomass, acid and heat.

11 is a result of analyzing the fatty acid composition of the biodiesel produced using methanol, ethanol and butanol as lower alcohols. MeOH, methanol; EtOH, ethanol; BuOH, butanol; C16: 0, Palmitic acid; C16: 1, Palmitoleic acid; C18, stearic acid; C18: 1, oleic acid; C18: 2, linoleic acid; C18: 3, linolenic acid.

12 is a result of analyzing the biodiesel production efficiency of the reused ethanol of the present invention, it compares the case of producing biodiesel using the reused ethanol and fresh ethanol.

In order to achieve the object of the present invention, the present invention

Pretreatment by adding alcohol to the wet biomass; And

After adding alcohol and a catalyst to the pretreated biomass, a method for producing biodiesel directly from the wet biomass without extracting lipids, comprising the step of performing a transesterification reaction by heating.

In the method according to an embodiment of the present invention, the wet biomass is a raw material capable of producing biodiesel as a living microorganism containing lipids, and may be any type of microalgae, yeast, mold, bacteria or microbial slurry, and fresh water. B may be a species of seawater, preferably microalgae, but is not limited thereto. The microorganism may be cultured by a heterotrophic, autotrophic or mixed nutrition.

The microalgae may be harvested by centrifugation, flocculation, bio-flocculation, filtration, etc., but are not limited thereto.

The microalgae of the present invention is Ettlia, Dunaliella, Chlorella, Nannochloropsis, Golenkinia, Spirulina, Chlamydomonas ( Chlamydomonas, Chroococcus, Chaetoceros, Achnanthes, Amphora species, and the like, preferably Ettlia oleoabundans , Nanocloc Rob cis Salina (Nannochloropsis salin a), nanno claw Rob cis Gardiner appear (Nannochloropsis gaditana), two flying it Ella right Wiltshire (Dunaliella bardawil), two flying it Ella Salina (Dunaliella salina), two flying it Ella Primo rekta (Dunaliella primolecta), chlorella Bulgari ( Chlorella vulgaris ), Chlorella emorsonii , Chlorella minutissima , Chlorella sorokiniana , Spirulina platensis , Cyclotella cryptica , Tetraselmis suecica , Monoraphidium , Botryococcus braunii , Stichococcus , Hamato Lactococcus flat ruby Alice (Haematococcus pluvialis), L ohdak tilrum tricot myuteom (Phaeodactylum tricomutum), isopropyl Cri cis galvanic or (Isochrysis galbana), Chemnitz shea Claus Te Solarium (Nitzschia closterium), Oran thio kit Solarium (Aurantiochytrium), Chlamydomonas Perlamulata ( Chlamydomonas perigranulata ) and the like, more preferably may be Ettlia sp or Nannochloropsis sp, but is not limited thereto. The bacterium may be Synechocystis and the like, but is not limited thereto. The yeast may be, but not limited to, Cryptococcus curvatus ( Cryptococcus curvatus ), Cryptococcus sp.

The cultured microalgae is 10 to 99% by weight, preferably 60 to 90% by weight, more preferably 80 to 90% by weight when used as a raw material for biodiesel production through the production method of the present invention after harvesting. It may be, but is not limited thereto.

In the method according to an embodiment of the present invention, the alcohol used in the pretreatment step may have a volume ratio of biomass: alcohol of 1: 0.1 to 100, preferably 1: 1 to 100, more preferably It may be 1: 1 to 10, and most preferably 1:10, but is not limited thereto.

In the method according to an embodiment of the present invention, the number of pretreatment may be one or more times, preferably 1 to 10 times, but is not limited thereto.

In the method according to an embodiment of the present invention, the alcohol of step (1) is very hygroscopic and is not limited so long as it may cause dehydration, preferably methanol, ethanol, propanol or butanol, and the like. It may be a lower alcohol, most preferably ethanol, but is not limited thereto. The alcohol may inhibit the lipase that removes excess water in the biomass, lowers the yield of biodiesel, or inhibits the activity of the inhibitor of the transesterification reaction.

In addition, the alcohol used in the pretreatment may preferably be recycled and used during the process for producing the biodiesel of the present invention, but is not limited thereto.

In a method according to an embodiment of the present invention, a catalyst of a transesterification reaction is used to produce a biodiesel of fatty acid ester from the pretreated wet biomass, wherein the catalyst is an acid catalyst, a base catalyst, a homogeneous ), A heterogeneous catalyst, an enzyme catalyst or any other catalyst, and the like, and preferably, a solid acid catalyst such as zeolite and heteropoly acid, an inorganic acid catalyst such as hydrofluoric acid, sulfuric acid and phosphoric acid, and a base catalyst such as sodium hydroxide and potassium hydroxide. It may be an ion exchange resin catalyst such as Amberlyst, more preferably an acid catalyst such as sulfuric acid, hydrochloric acid, nitric acid, acetyl chloride, and more preferably sulfuric acid, but is not limited thereto.

In the biodiesel production process of the present invention, alcohol and catalyst may be reused one or more times to increase the biodiesel content in the reaction mixture.

In addition, in the method according to an embodiment of the present invention, the step of the transesterification reaction may be heated for 60 to 150 ℃, preferably 80 to 120 ℃, and reacted for 5 to 300 minutes at a stirring speed of 10 to 300 rpm However, the present invention is not limited thereto.

Therefore, the present invention preferably

(1) pretreatment by adding alcohol to the wet microalgae; And

(2) adding alcohol and an acid catalyst to the pretreated microalgae, and heating at 60-150 ° C. to perform a transesterification reaction for 10-300 minutes. Provided is a method for the direct preparation of fatty acid alkyl esters from algae.

Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited to the following examples.

Example 1 Preparation of Microalgae Wet Biomass

Microalga Ettlia sp, Chlorella protothecoides or Nannochloropsis sp in a 500 ml flask, a 20 l reactor and a 1000 l outdoor bulk culture channel using fresh or seawater The ponds were cultured by independent, mixed or heterotrophic methods.

Dry cell concentration in the culture medium varied from 0.1% to 1.4% (w / v). Cell concentrations were found high in the heterotrophic state and low in the autotrophic state. Cultured cells exhibited high levels of water content both intracellularly and extracellularly. Extracellular water was dehydrated using one of the known methods in microbial production, including but not limited to membrane filtration, centrifugation, precipitation or flotation (floating). Yeast cell Cryptococcus curvatus and Cryptococcus sp. Were grown for 16 hours at 25 ° C. in organic defined medium supplemented with nitrogen and a carbon source. Since the harvested biomass shows various changes in the intracellular contents of water and lipids, the harvested biomass was stored at -80 ° C until used in the process.

0.3g of cells are dried using a freeze drying method to know the exact amount of water in the cells, and the dried cells are analyzed by conventional fatty acid methyl ester (FAME) content analysis method and gas chromatography (GC). Analyzed. In addition, the lipid content of the dry biomass was analyzed through the following steps: Approximately 10 mg of dry algal cells were mixed with 2 ml of a 2: 1 chloroform: methanol solution and capped with a Teflon capped Pyrex tube The lipid was extracted by stirring for 10 minutes at. Thereafter, 1 ml of chloroform containing 0.5 mg of heptadecanoic acid (C17: 0) was added to the tube with an internal standard, and 1 ml of methanol and 300 µl of sulfuric acid were added using a Wise Sum HB 96-D heating block. It was added for transesterification reaction under the temperature of ℃. After the reaction, the sample tubes were cooled to room temperature in water, and 1 ml of distilled water was added to rinse the residual methanol and sulfuric acid, followed by centrifugation for phase separation. The lower chloroform layer was washed with 0.2 μm PVDF syringe filter (Whatman, UK). After filtration through, it was used for gas chromatography analysis. Gas chromatography analysis for all samples was performed using Agilent 6890 Gas Chromatography (Agilent, USA) equipped with a flame ionization detector and HP19091N-213 HP-INNOWax polyethylene glycol column (Agilent). Each fatty acid methyl ester (FAME) peak was identified and quantified with reference to the 37 component FAME standard mix (Supelco, USA). Total lipid amount was calculated by summing all peaks except the peaks of solvent and internal standard.

After harvesting, the microbial biomass naturally contains between about 60 and 90% moisture. Wet biomass of microalgae has many inhibitors that inhibit the transesterification process during biodiesel manufacturing. Therefore, in this process, we washed the wet biomass using a microbiologically synthesized solvent to inactivate inhibitors such as water or enzymes. Wet biomass was mixed with a microbiologically synthesized solvent at a rate of 1: 1-10 at a speed of 300 rpm in a vibrating machine. Solvents serve to stop the activity of enzymes that can degrade lipids and remove excess water that interferes with the process of biodiesel production. The solvent is then separated from the biomass through known separation methods such as centrifugation, filtration and precipitation.

Example 2 Optimization of Pretreatment Conditions: Treatment Time

Microalgae cells were pretreated due to the fact that intracellular lipids were sequestered after thick cellulose structures. Microalgal strains of Atria with relatively thick cell walls were cultured and microalgae were harvested by centrifugation. The moisture content of the harvested microalgal samples was in the range of 80-90%.

First, the effects of alcohol in the pretreatment process, ethanol in the present invention, and treatment time were investigated. Different treatment times were given from 10 to 60 minutes to compare biodiesel production. Theoretically, since ethanol dehydrates cells almost instantaneously, the effect of increasing the ethanol treatment time was predicted to be negligible. As a result of measuring the amount of produced fatty acid ethyl ester (FAEE), no change in biodiesel production with treatment time was observed, and the amount of produced fatty acid ethyl ester was confirmed at a constant level at all treatment times (FIG. 2). This shows that the ethanol pretreatment process of the present invention simultaneously destroys the cell structure with rapid dehydration.

Example 3 Optimization of Pretreatment Conditions: Number of Treatments

After confirming the effect of ethanol treatment time, the effect of the number of times of ethanol pretreatment on the production of biodiesel was investigated. The wet biomass sample was subjected to 0, 1 and 2 replicates of ethanol pretreatment before the direct transesterification step. As a result, when the number of times of pretreatment increased from 0 times (no treatment) to two times, it was observed that the production amount of fatty acid ethyl ester (FAEE) increased more than four times (Fig. 3). It was expected that repetition of the ethanol pretreatment process would result in complete dehydration of the wet biomass sample, with the effect of increasing biodiesel yield.

Example 4 Optimization of Pretreatment Conditions: Ethanol Amount

Increasing the ratio of ethanol to wet biomass during the pretreatment and transesterification steps was expected to increase the yield of fatty acid ethyl esters (FAEE). First, biodiesel production was compared under the condition that the ratio of ethanol to wet biomass was 1: 1 to maximum 1:10 during the pretreatment. As a result, a 6-fold increase in the production of fatty acid ethyl ester (FAEE) was observed in proportion to the increase in the ratio of ethanol to the wet biomass (Fig. 4).

Example 5 Optimization of Transesterification (Conversion) Conditions: Time

After optimization of the pretreatment conditions, the conditions for direct in situ transesterification (conversion) from triglycerides (TAG) to fatty acid ethyl esters (FAEE) were optimized. For the study of conversion optimization conditions, wet biomass samples were obtained from a 200 m ³ open pond, an outdoor mass culture facility. The microalgae used are Nannochloropsis oceanica , a seawater aquaculture system, which has a relatively high lipid content. The moisture content of the wet biomass sample was found to be in the range of 65-70%.

Increasing the duration of the transesterification reaction was expected to improve the biodiesel production yield, thus confirming the change in yield while increasing the conversion duration to 10, 30, 60 and 120 minutes. As a result, it was confirmed that the yield of the in situ transesterification reaction gradually increased as the conversion duration increased (FIG. 5).

When discharging lipids to the upper layer, the maximum total efficiency of the process we can achieve was 114% of the Bree drying method.

Example 6 Optimization of Transesterification (Conversion) Conditions: Temperature Conditions

The effect of reaction temperature on conversion was checked to find the optimal conditions for transesterification reaction. It is hypothesized that higher reaction temperatures will bring higher conversion yields, and are expected to be even more energy integrated, especially above 100 ° C. The transesterification reaction was performed using a wet biomass for 2 hours at a temperature section between 60 ~ 120 ℃. As a result, 8.14 mg of fatty acid ethyl ester was produced at a temperature of 60 ° C., and 10.76 mg of biodiesel was produced at a temperature of 120 ° C., confirming an increase of about 32% (FIG. 6). However, especially after the reaction temperature was increased to 100 ° C. or more, no increase was observed as much as the conversion period experiment conducted in Example 5. This suggests the possibility of achieving high yields at low conversion temperatures while other conditions are being optimized.

Example 7 Optimization of Transesterification (Conversion) Conditions: Amount of Catalyst

Optimization Conditions for Conversion Time and Reaction Temperature After the experiment, the amount of catalyst in the transesterification reaction was varied to focus on the effect. For this purpose 98% sulfuric acid (H ₂ SO ₄ ) was used as the acid catalyst for the transesterification reaction. We added 100, 300 and 500 μl of the catalyst to 3 ml of the total reaction volume and confirmed the yield of fatty acid ethyl ester (FAEE) through a 2 hour conversion at 80 ° C. temperature conditions. As a result, it was observed that as the amount of catalyst increased, the conversion yield did not increase (FIG. 7), indicating that biodiesel can be produced effectively even with a small amount of catalyst in the process of the present invention.

In addition, heterogeneous catalyst Amberlyst-15 (surface area 50 m ² / g) was used as a catalyst for the direct transesterification of Ettlia sp. Biomass instead of sulfuric acid. The conversion time was 2 hours and compared with the amount of fatty acid ethyl ester of the reaction via sulfuric acid catalyst. As a result, in the case of Amberlyst, the conversion yield of the sulfuric acid catalyst was not reached, but it was confirmed that the conversion yield increased as the amount of use thereof increased (FIG. 8). In addition, as a result of increasing the duration of the transesterification reaction by using 500 mg of Amberlyst as a catalyst, it was confirmed that the biodiesel production yield was improved as in the case of Example 5 described above (FIG. 9).

Example 8 Changes in Lipid Distribution in the Process

Investigation of lipid distribution in the process of the present invention showed that unconverted lipids remained in trace biomass while most fatty acid esters were found in the alcohol fraction (FIG. 10).

In the case of Nannochloropsis, some biomass extracts large amounts of these lipids during pretreatment. These extracted lipids in the pretreated alcohol fraction are collected and subsequently subjected to transesterification.

Example 9 Comparison Between Microalgal Strains

After optimization of pretreatment and conversion conditions, four different species of microalgae, Ettlia sp., Nannochloropsis oceanica , Aurantiochytrium and Gorenkinia species (Golenkinia sp.), chlorella was measured the overall efficiency of the process of the invention using a vulgaris (chlorella vulgaris) and nanno claw Rob cis Salina (Nannochloropsis salina). The method was calculated by measuring the content of total fatty acid ethyl ester (FAEE), and compared with the conventional dry Bligh Dyer as an analytical process for benchmarking other extraction processes. As a result, the production efficiency of the biodiesel through the process of the present invention was found to be superior to or similar to the efficiency of the conventional dry bridging method, although there are differences depending on the strain characteristics (Table 1).

Table 1

Example 10 Production of Biodiesel Using Lower Alcohol

Biodiesel was produced using methanol and butanol, lower alcohols than ethanol. The production method uses microalgae of Ettlia sp., Which has about 75% water content, as biomass, and performs pretreatment once for 10 minutes with a biomass: alcohol volume ratio of 1:10. , 100 μl of sulfuric acid was used as a catalyst and transesterification was carried out at 120 ° C. for 2 hours. The resulting biodiesel was analyzed for fatty acid composition using gas chromatography.

As a result, biodiesel could be produced in all cases using methanol, ethanol and butanol, and the yield was confirmed to be similar. In addition, in the case of fatty acid ethyl ester (FAEE) produced using ethanol, the total production was 10.6 mg, and the analysis of fatty acid composition through gas chromatography showed that palmitic acid (C16: 0) and palmitoleic acid. (Palmitoleic acid, C16: 1) is 2.0 and 0.3mg, respectively, stearic acid (C18), oleic acid (C18: 1), linoleic acid (C18: 2), and linolenic acid (C18: 1) : 3) were 0.4, 2.7, 1.6, and 1.3 mg, respectively. Even in the case of producing biodiesel using methanol and butanol in addition to ethanol, the total production amount and fatty acid composition ratio of fatty acid methyl ester (FAME) and fatty acid butyl ester (FABE) were similar to those produced using biodiesel using ethanol. Is shown (FIG. 11). In addition, the production and efficiency of the biodiesel was confirmed to be similar or superior to the production efficiency of the conventional dry bridging method.

Example 11. Biodiesel Conversion Efficiency of Reusable Ethanol

Ethanol mixtures mixed with fatty acid ethyl esters (FAEE) produced from the completed reactions according to the biodiesel production process of the present invention were used in the conversion reaction for biodiesel production of the next batch of microalgal biomass. 200 ml of Gorenkinia wet type biomass (74.9% water content) was treated with 2 ml of fresh ethanol as a pretreatment for dehydration, and transesterified with recycled ethanol and sulfuric acid or fresh ethanol and sulfuric acid. Sulfuric acid was treated at various concentrations from 0 to 200 μl to confirm the reusability of the acid catalyst.

As a result, there was no significant change in the amount of biodiesel obtained from reused ethanol, but the amount of biodiesel produced from biomass was confirmed to be more produced in the reaction using reused ethanol than the reaction using fresh ethanol. In addition, as shown in the result of Example 7, the amount of the sulfuric acid catalyst was confirmed that even if the amount of increase does not significantly affect the production of biodiesel (Fig. 12). From the above results, it can be seen that in the direct preparation method of the biodiesel of the present invention, the biodiesel content (v / v%) may be increased in the reaction mixture by reusing the alcohol and the catalyst several times.

Claims (16)

1. (1) pretreatment by adding alcohol to the wet biomass; And

   (2) directly adding the alcohol and the catalyst to the pretreated biomass, followed by heating to perform a transesterification reaction, wherein the method of producing biodiesel directly from the wet biomass without extracting lipids.
2. The method of claim 1, wherein the wet biomass is a lipid-containing microorganism.
3. The method of claim 2, wherein the lipid-containing microorganism is microalgae, yeast, mold or bacteria.
4. 4. The method of claim 3, wherein the microorganism is cultured by heterotrophic, autotrophic or mixed nutrition.
5. According to claim 3, wherein the microalgae are Ettlia, Dunaliella, Chlorella, Nannochloropsis, Golenkinia, Spirulina, Chlamydomonas, Cyclotella, Tetraselmis, Monooraphidium, Botryococcus, Stichococcus, Haematococcus, Pae Phaeodactylum, Isochrysis, Nitzschia, Aurantiochytrium, Chrococcus, Chaetoceros, Achnanthes, and Emporas (Achnanthes) Amphora) A method for producing biodiesel directly from a wet biomass, characterized in that at least one selected from the group consisting of.
6. The method of claim 1, wherein the moisture content of the wet biomass is 10 to 99% by weight.
7. The method of claim 1, wherein the volume ratio of the wet biomass: alcohol of the step (1) is 1: 0.1 to 100, characterized in that the direct production of biodiesel from the wet biomass.
8. The method of claim 1, wherein the number of pretreatments in step (1) is one or more times.
9. The method of claim 1, wherein the alcohol is a C1 to C4 lower alcohol.
10. 10. The method of claim 9, wherein the lower alcohol is recycled.
11. The method of claim 10, wherein the lower alcohol and catalyst are reused one or more times.
12. The method of claim 1, wherein the heating is performed at 60 ° C. to 150 ° C. 6.
13. The method of claim 1, wherein the transesterification is carried out for 5 to 300 minutes.
14. The method of claim 1, wherein the catalyst is an acid catalyst, a base catalyst, a homogeneous catalyst, a heterogeneous catalyst or an enzyme catalyst.
15. 15. The method of claim 14, wherein the acid catalyst is any one selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid and acetyl chloride.
16. (1) pretreatment by adding alcohol to the wet microalgae; And

    (2) adding alcohol and an acid catalyst to the pretreated microalgae, and heating at 60-150 ° C. to perform a transesterification reaction for 10-300 minutes. Process for the direct preparation of fatty acid alkyl esters from algae.

Images