Biomass component cleaning and separating and liquid fertilizer co-production method based on biogenic amine solvent system

Abstract

The invention discloses a biomass component clean separation and liquid fertilizer co-production method based on a biogenic amine solvent system, biomass components can be disassembled under mild reaction conditions by using excellent lignin dissolving capacity of ethanolamine, lignin is selectively and efficiently removed, and the holocellulose retention rate of obtained filter residues is high. Meanwhile, due to good biocompatibility and low toxicity of the ethanolamine solvent, filter residues can be directly used for enzymolysis saccharification without a washing process; the lignin in the filtrate can be separated and recovered by adjusting the pH value through an acidic solution. The waste liquid after lignin recovery contains major elements such as N, P and K, and can be used as a liquid fertilizer; the strain can also be coupled with growth-promoting rhizobacteria such as pseudomonas putida and pseudomonas aeruginosa to prepare microbial fertilizers.

Description

Technical field:

[0001] The invention relates to the field of biomass component separation and conversion and waste liquid resource utilization, and in particular to a method for cleanly separating biomass components and co-producing liquid fertilizer based on a biogenic amine solvent system. Background technology:

[0002] Agricultural and forestry waste contains a large amount of lignocellulosic raw materials, including various types of crop straw and forestry waste wood as well as scraps from the processing of agricultural and forestry products. Agricultural and forestry waste is the most abundant biomass resource in the Earth's biosphere. It is mainly composed of cellulose, hemicellulose and lignin. The components are connected by different chemical bonds to form a complex network structure, forming an anti-degradation barrier for the cell walls of higher plants, making it difficult to be directly converted and utilized.

[0003] Pretreatment can destroy the cross-linking areas between components, relax the cell wall structure, remove lignin and hemicellulose, expose the cellulose surface, increase the accessibility of cellulase and substrate, and ultimately facilitate the subsequent component separation and enzymatic fermentation process. Organic solvents are excellent solvents for removing lignin. Currently, conventional organic solvents for biomass pretreatment mainly include polyols, organic acids and ketones. Although organic solvent pretreatment has the excellent characteristics of efficient component disassembly performance, high cellulose retention rate, high purity of recovered lignin and easy conversion, most organic solvent systems have shortcomings such as strong biological toxicity, harsh reaction conditions and low component conversion efficiency, as well as high energy consumption for solvent recovery and the need for improvement in the harmless treatment of waste liquid at the end, which limits the large-scale industrial application of organic solvent pretreatment technology. Summary of the invention:

[0004] The object of the present invention is to provide a method for cleanly separating biomass components and co-producing liquid fertilizer based on a biogenic amine solvent system.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for cleanly separating biomass components and co-producing liquid fertilizer based on a biogenic amine solvent system, the method comprising the following steps:

[0007] (1) adding a biomass raw material and a biogenic amine solution into a reaction vessel at a mass volume ratio of 1:(10-20) g / mL, placing the reaction vessel in a constant temperature shaker, and reacting at 30°C-70°C for 3 hours; after the reaction, separating the solid and the liquid to obtain a filter residue rich in cellulose and hemicellulose and a filtrate containing lignin; the biogenic amine solution system is an ethanolamine-water solution containing a solid alkaline catalyst, wherein the volume fraction of ethanolamine is 20%-80%, preferably 40%-60%, and the concentration of the solid alkaline catalyst is 0.005-0.02 g / mL;

[0008] (2) The filter residue obtained in step (1) can be directly used in the enzymatic conversion process without washing. The pH of the filtrate obtained in step (1) is adjusted to 2 with an acidic solution. After solid-liquid separation, lignin is recovered. The waste liquid contains macro elements such as N, P, and K, which can be used as liquid fertilizer or as a carbon and nitrogen source for plant growth-promoting rhizobacteria such as Pseudomonas putida and Pseudomonas aeruginosa, and is coupled to prepare microbial fertilizer.

[0009] The biomass raw materials are lignocellulosic agricultural and forestry wastes such as crop straws, bagasse, bamboo and wood, and energy plants such as Miscanthus, switchgrass and Pennisetum alopecuroides.

[0010] Preferably, the biomass raw materials are crushed and screened to obtain particles with a size of 20-60 mesh and a particle size of 0.5-3 mm.

[0011] Preferably, the solid base catalyst in step (1) is a strong base or a basic salt of a weak acid with good water solubility. Preferably, the strong base is KOH, and the basic salt of a weak acid is K 3 PO 4 .

[0012] Preferably, the filter residue (containing cellulose and hemicellulose components) obtained in step (1) is used for enzymatic saccharification. The main steps are as follows: the mass concentration of the filter residue (substrate) is 5%, the CTec3 enzyme amount is 20 FPU / g cellulose, acetic acid-sodium acetate solution is used as the enzymatic hydrolysis buffer, the pH is adjusted to 4.8, at 50 °C and 150 rpm, and the reaction is carried out for 72 h to obtain a mixed solution of glucose and xylose.

[0013] Preferably, the acidic solution in step (2) is phosphoric acid solution.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1) The relative energy difference (RED) value of the ethanolamine-lignin system in the present invention is 0.788, which is lower than that of conventional biobased-derived solvents such as ethanol (1.37), tetrahydrofuran (1.06) and valerolactone (1.38). It has good lignin dissolution ability, high biocompatibility, low biotoxicity and biodegradable properties, and is environmentally friendly.

[0016] 2) The ethanolamine-aqueous solution system constructed in the present invention has mild reaction conditions, 30 °C - 70 °C, a wide range of applicable raw materials, can selectively and efficiently remove lignin, and the retention rates of cellulose and hemicellulose components in the obtained solid filter residue are high. And due to the good biocompatibility of the solvent, the filter residue can be directly used in the enzymatic saccharification process without washing steps, reducing water consumption.

[0017] 3) The biomass component cleaning and separation method provided by the present invention enables the efficient recovery of lignin by adjusting the pH of black liquor with phosphoric acid, and the purity is higher than 85%; the remaining waste liquid contains nutrients such as N, P, and K, which can be used as liquid fertilizers to achieve the resource utilization of the waste liquid.

[0018] In summary, the present invention utilizes the excellent lignin dissolution ability of ethanolamine to disassemble biomass components under mild reaction conditions, selectively and efficiently remove lignin, and the residue of holocellulose has a high retention rate. At the same time, due to the good biocompatibility and low toxicity of the ethanolamine solvent, the residue can be directly used for enzymatic hydrolysis and saccharification without washing; the lignin in the filtrate can be separated and recovered by adjusting the pH with an acidic solution. The waste liquid after recovering lignin contains macro elements such as N, P, and K. By adjusting the ratio of N, P, and K and adding appropriate medium and trace elements, it can be used as a liquid fertilizer; it can also be coupled with plant growth-promoting rhizobacteria such as Pseudomonas putida and Pseudomonas aeruginosa to prepare microbial fertilizers. The present invention can not only meet the requirements of clean separation of biomass components from agricultural and forestry waste, but also achieve the purpose of resource utilization of the waste liquid generated during the separation of the three elements, and contribute to the development of a low-carbon circular refining process for lignocellulose. Specific embodiments:

[0019] The following is a further description of the present invention, rather than a limitation of the present invention.

[0020] Example 1:

[0021] 1) 1 g of bagasse raw material with a particle size of 0.5 mm (cellulose 44.5 wt%, hemicellulose 26.8 wt%, lignin 23.4 wt%) and an ethanolamine solution were added to the reactor at a mass-volume ratio of 1:20 g / mL. The volume fraction of ethanolamine was 40%, and the concentration of the catalyst KOH was 0.01 g / mL. The reaction was carried out at 30 °C and 150 rpm for 3 h. After the reaction, solid-liquid separation was performed to obtain a residue rich in cellulose and hemicellulose and a filtrate containing dissolved lignin; the recovery rate of the residue was 84.1%, and the contents of the three elements were: cellulose 52.0 wt%, hemicellulose 28.8 wt%, lignin 13.4 wt%. Among them, the retention rate of holocellulose was 95.3%, and the lignin removal rate was 52.0%.

[0022] 2) Using the unwashed filter residue rich in cellulose and hemicellulose components as the enzymatic hydrolysis substrate, with a mass concentration of 5%, CTec3 enzyme amount of 20 FPU / g of cellulose, using acetic acid - sodium acetate solution as the enzymatic hydrolysis buffer, adjusting the pH = 4.8, at 50 °C, 150 rpm, reacting for 72 h, a mixed solution of glucose and xylose is obtained, and the degradation efficiencies of cellulose and hemicellulose are 52.4% and 54.9% respectively. Adjust the pH of the filtrate obtained in step (1) to 2 with an acidic solution, after solid - liquid separation, lignin is recovered, and the waste liquid contains a large number of elements such as N, P, and K, which is used as the carbon source and nitrogen source for plant - growth - promoting rhizobacteria such as Pseudomonas putida and Pseudomonas aeruginosa, and is coupled to prepare microbial fertilizer.

[0023] Example 2

[0024] 1) 1 g of sugarcane bagasse raw material with a particle size of 0.5 mm (cellulose 44.5 wt%, hemicellulose 26.8 wt%, lignin 23.4 wt%) and ethanolamine solution are added to the reactor according to the mass - to - volume ratio of 1:20 g / mL. The volume fraction of ethanolamine is 40%, the concentration of catalyst KOH is 0.01 g / mL, reacting at 50 °C, 150 rpm for 3 h. After the reaction, solid - liquid separation is carried out to obtain a filter residue rich in cellulose and hemicellulose and a filtrate containing dissolved lignin; the recovery rate of the filter residue is 77.1%, and the contents of the three components are: cellulose 55.1 wt%, hemicellulose 28.9 wt%, lignin 9.4 wt%. Among them, the retention rate of holocellulose is 90.9%, and the lignin removal rate is 69.2%.

[0025] 2) Using the unwashed filter residue rich in cellulose and hemicellulose components as the enzymatic hydrolysis substrate, with a mass concentration of 5%, CTec3 enzyme amount of 20 FPU / g of cellulose, using acetic acid - sodium acetate solution as the enzymatic hydrolysis buffer, adjusting the pH = 4.8, at 50 °C, 150 rpm, reacting for 72 h, a mixed solution of glucose and xylose is obtained, and the degradation efficiencies of cellulose and hemicellulose are 71.6% and 73.0% respectively. Adjust the pH of the filtrate obtained in step (1) to 2 with an acidic solution, after solid - liquid separation, lignin is recovered, and the waste liquid contains a large number of elements such as N, P, and K, which is used as the carbon source and nitrogen source for plant - growth - promoting rhizobacteria such as Pseudomonas putida and Pseudomonas aeruginosa, and is coupled to prepare microbial fertilizer.

[0026] Example 3

[0027] 1) 1 g of bagasse raw material with a particle size of 3 mm (cellulose 44.5 wt%, hemicellulose 26.8 wt%, lignin 23.4 wt%) and ethanolamine solution were added into the reactor at a mass-to-volume ratio of 1:20 g / mL. The volume fraction of ethanolamine was 20%, the concentration of catalyst KOH was 0.01 g / mL, and the reaction was carried out at 70 °C and 150 rpm for 3 h. After the reaction, solid-liquid separation was performed to obtain the filter residue rich in cellulose and hemicellulose and the filtrate dissolved with lignin; the recovery rate of the filter residue was 72.6%, and the contents of the three components were: cellulose 57.6 wt%, hemicellulose 28.9 wt%, lignin 7.4 wt%. Among them, the retention rate of holocellulose was 88.1%, and the lignin removal rate was 77.1%.

[0028] 2) Using the unwashed filter residue rich in cellulose and hemicellulose components as the enzymatic hydrolysis substrate, with a mass concentration of 5%, the CTec3 enzyme dosage of 20 FPU / g of cellulose, using acetic acid-sodium acetate solution as the enzymatic hydrolysis buffer, adjusting the pH = 4.8, at 50 °C and 150 rpm, reacting for 72 h, to obtain a mixed solution of glucose and xylose. The degradation efficiencies of cellulose and hemicellulose were 82.8% and 79.7% respectively. The pH of the filtrate obtained in step (1) was adjusted to 2 with an acidic solution, and after solid-liquid separation, lignin was recovered and freeze-dried, and its purity was higher than 85%. The waste liquid after recovering lignin contained a large amount of elements such as N, P, and K, and then the pH was adjusted to neutral with KOH, showing a light yellow color, and used as a liquid fertilizer.

[0029] Using clear water as the control group, the above liquid fertilizer was diluted 400 times (Group 1) and 1600 times (Group 2) respectively, and rice seedlings were cultivated by hydroponics in an artificial climate chamber to evaluate the efficacy of the waste liquid as a liquid fertilizer. The cultivation conditions in the artificial climate chamber were: 16 h of light, light intensity 16000 Lux, 28 °C; 8 h of darkness, 25 °C; humidity 75%. After two weeks of cultivation, the agronomic traits and photosynthetic pigment contents of the rice seedlings are shown in Table 1.

[0030] Table 1 Agronomic traits and photosynthetic pigment contents of rice seedlings after two weeks of cultivation

[0031]

[0032] Note: The biological trait data are the average values of 30 rice seedlings, and the photosynthetic pigment content is the average value of two parallel experiments.

[0033] As can be seen from Table 1, compared with the clear water control group, due to the rich N, P, K and other nutrient elements and small molecule lignin in the waste liquid, after diluting with an appropriate multiple, the plant height, fresh weight and dry weight of rice seedlings can be significantly increased, and the photosynthetic pigment contents in their fresh leaves all increase to varying degrees. The above results show that the waste liquid after recovering lignin in Example 3 of the present invention has the efficacy of a liquid fertilizer, and the resource utilization of the waste liquid in the lignocellulose component separation process can be realized.

[0034] Example 4

[0035] Referring to Example 3, the difference is that the volume fraction of ethanolamine is 40%.

[0036] Example 5

[0037] Referring to Example 3, the difference is that the volume fraction of ethanolamine is 60%.

[0038] Example 6

[0039] Referring to Example 3, the difference is that the volume fraction of ethanolamine is 80%.

[0040] Comparative Example 1:

[0041] Referring to Example 3, the difference is that the volume fraction of ethanolamine is 15%.

[0042] Comparative Example 2:

[0043] Referring to Example 3, the difference is that the volume fraction of ethanolamine is 90%.

[0044] Table 2 Influence of Different Volume Fractions of Ethanolamine on the Separation of Bagasse Components

[0045]

[0046] As can be seen from Table 2, when the volume fraction of ethanolamine is 15%, the lignin removal rate is not high. As the volume fraction of ethanolamine gradually increases, the lignin removal rate gradually increases, but the lignin removal rate decreases instead after the volume fraction of ethanolamine exceeds 60%. Therefore, the volume fraction of ethanolamine is selected to be 20%-80%, preferably 40%-60%.

Claims

1. A method for clean separation of biomass components and co-production of liquid fertilizer based on a biogenic amine solvent system, characterized in that: The method comprises the following steps: (1) adding a biomass raw material and a biogenic amine solution into a reaction vessel at a mass volume ratio of 1:(10-20) g / mL, placing the reaction vessel in a constant temperature shaker, and reacting at 30°C-70°C for 3 hours; after the reaction, separating the solid and the liquid to obtain a filter residue rich in cellulose and hemicellulose and a filtrate containing lignin; the biogenic amine solution system is an ethanolamine-water solution containing a solid alkaline catalyst, wherein the volume fraction of ethanolamine is 20%-80%, and the concentration of the solid alkaline catalyst is 0.005-0.02 g / mL; (2) The filter residue obtained in step (1) is exempted from the washing process and is directly used in the enzymatic conversion process. The pH value of the filtrate obtained in step (1) is adjusted to 2 with an acidic solution. After solid-liquid separation, lignin is recovered, and the waste liquid is used as a liquid fertilizer or as a carbon source and nitrogen source for Pseudomonas putida and Pseudomonas aeruginosa to prepare a microbial fertilizer.

2. The method according to claim 1, characterized in that The biomass raw material is lignocellulose agricultural and forestry waste or energy plants.

3. The method according to claim 2, characterized in that The lignocellulosic agricultural and forestry waste is selected from any one of straw, bagasse, bamboo and wood.

4. The method according to claim 2, characterized in that: The energy plant is selected from Miscanthus sinensis, switchgrass or Pennisetum virgatum.

5. The method according to claim 1, characterized in that: The biomass raw material has a particle size of 0.5-3 mm after being crushed.

6. The method according to claim 1, characterized in that The solid alkaline catalyst in step (1) is a strong base or a salt of a strong base and a weak acid with good water solubility.

7. The method according to claim 6, characterized in that The strong base is KOH, and the strong base weak acid salt is K3PO4.

8. The method according to claim 1, characterized in that The volume fraction of ethanolamine is 40%-60%.

9. The method according to claim 1, characterized in that: The filter residue obtained in step (1) is used for enzymatic saccharification, and the main steps are: the filter residue mass concentration is 5%, the CTec3 enzyme amount is 20 FPU / g cellulose, acetic acid-sodium acetate solution is used as the enzymatic buffer, the pH is adjusted to 4.8, 50°C, 150rpm, and the reaction is performed for 72h to obtain a mixed solution of glucose and xylose.

10. The method according to claim 1, characterized in that The acidic solution in step (2) is a phosphoric acid solution.

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