Method for preparing ethanol and co-producing fulvic acid from straws

Abstract

The invention provides a method for preparing ethanol and co-producing fulvic acid from straws, which comprises the following steps: adding a catalyst into the straws in an ammonium sulfite aqueous solution to carry out cooking treatment, and carrying out solid-liquid separation to obtain straw residues and filtrate; the filtrate comprises fulvic acid. The process flow is simple, and large-scale production is easy to realize.

Description

Technical Field

[0001] The present invention relates to the technical field of biochemistry, and particularly relates to a method for co-producing ethanol from straw and fulvic acid. Background Art

[0002] With the gradual depletion of petroleum resources and the increasingly deteriorating environment, vigorously promoting the use of renewable energy technologies has become an important part of the energy development strategies of many countries to reduce dependence on fossil energy and greenhouse gas emissions. Cellulose ethanol technology is a high-end clean energy technology because it can be used to replace traditional grain ethanol technology and produce clean ethanol fuel using the widely existing cellulosic biomass raw materials on the earth. It not only avoids environmental pollution caused by straw burning, is beneficial to carbon emission reduction, but also avoids the problem of competing with the people for food and alleviates the energy crisis.

[0003] Cellulose and hemicellulose in straw are enzymatically hydrolyzed to prepare hexose, pentose, etc., and lignin can be used in benzene chemical industry, preparation of plant-derived fulvic acid, etc. And plant-derived fulvic acid used in the production of organic fertilizer for returning to the field has the following effects: 1. When used in combination with chemical fertilizers, it can enhance the efficacy of chemical fertilizers, improve the utilization rate of chemical fertilizers, and reduce the amount of chemical fertilizers used. 2. It is easily absorbed by crops, can promote crop growth, enhance stress resistance, increase the yield of agricultural products, and improve the quality of agricultural products. 3. It increases the population of soil microorganisms, improves soil organic matter (increasing the microorganisms and black soil in the soil), enhances the nutrient content of the soil layer, reduces the loss of nutrients in the soil layer, is beneficial to the protection of black land, the construction of high-standard farmland, and the double reduction action, etc., which not only meets the national strategic needs of green and low-carbon development, but also reflects the high-value utilization of agricultural waste.

[0004] However, the existing process for preparing ethanol from straw is relatively cumbersome. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings in the prior art and provide a method for co-producing ethanol from straw and fulvic acid.

[0006] The present invention provides a method for co-producing ethanol from straw and fulvic acid, comprising the following steps:

[0007] The straw is subjected to cooking treatment by adding a catalyst in an aqueous solution of ammonium sulfite, and then solid-liquid separation is carried out to obtain straw residue and filtrate; the filtrate contains fulvic acid, and the catalyst is selected from one or more of persulfate, peroxide or nitrite.

[0008] In some embodiments, the catalyst is selected from one or more of ammonium persulfate, potassium persulfate, peroxy nitric acid or potassium nitrite.

[0009] In some embodiments, the dosage of the catalyst is 0.05-0.2% relative to the dry weight of the straw, such as 0.06%, 0.08%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18% or 0.2%.

[0010] In some embodiments, the temperature of the cooking treatment is 150°C to 190°C, such as 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C or 190°C.

[0011] In some embodiments, the temperature of the cooking treatment is 160-180°C.

[0012] In some embodiments, the pressure of the cooking treatment is 0.6-1.2 MPa, such as 0.6 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa or 1.2 MPa.

[0013] In some embodiments, the time of the cooking treatment is 0.6-4 hours, such as 0.6 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0014] In some embodiments, the time of the cooking treatment is 1-3 hours.

[0015] In some embodiments, the weight ratio of the straw to the aqueous ammonium sulfite solution is 1:(1-5), such as 1:1, 1:2, 1:3, 1:4 or 1:5.

[0016] In some embodiments, the weight ratio of the straw to the aqueous ammonium sulfite solution is 1:(1.5-4).

[0017] In some embodiments, the dosage of ammonium sulfite in the aqueous ammonium sulfite solution is 8%-15% relative to the dry weight of the straw, such as 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%.

[0018] In some embodiments, the dosage of ammonium sulfite in the aqueous ammonium sulfite solution is 10-12% relative to the dry weight of the straw.

[0019] In some embodiments, the straw is selected from one or more of wheat straw, rice straw, corn straw, sorghum straw, reed, giant reed or cotton straw.

[0020] In some embodiments, the method further includes: refining and concentrating the filtrate to obtain liquid fulvic acid.

[0021] In some embodiments, the concentration is carried out using an MVR concentration device.

[0022] In some embodiments, the filtrate is dried to obtain a solid fulvic acid product.

[0023] In some embodiments, the drying is spray drying.

[0024] In some embodiments, the method further includes: washing the straw residue, and then performing enzymatic hydrolysis to obtain an enzymatic hydrolysis product.

[0025] In some embodiments, the washing treatment is carried out with water.

[0026] In some embodiments, in the washing treatment, the mass ratio of the straw residue to water is 1:(1 - 5), such as 1:1, 1:2, 1:3, 1:4, or 1:5.

[0027] In some embodiments, the enzyme used for the enzymatic hydrolysis is selected from one or more of cellulase, cellobiase, or xylanase.

[0028] In some embodiments, the addition amount of cellulase is 0 - 100 FPA / g dry matter (such as 5 FPA / g dry matter, 10 FPA / g dry matter, 15 FPA / g dry matter, 20 FPA / g dry matter, 25 FPA / g dry matter, 30 FPA / g dry matter, 35 FPA / g dry matter, or 40 FPA / g dry matter, 50 FPA / g dry matter, 60 FPA / g dry matter, 70 FPA / g dry matter, 80 FPA / g dry matter, 90 FPA / g dry matter), the addition amount of xylanase is 0 - 3000 U / g dry matter (such as 100 FPA / g dry matter, 500 FPA / g dry matter, 1000 FPA / g dry matter, 1500 FPA / g dry matter, 2000 FPA / g dry matter, 2500 FPA / g dry matter, 3000 FPA / g dry matter), and the addition amount of cellobiase is 2 - 100 U / g dry matter (such as 5 FPA / g dry matter, 20 FPA / g dry matter, 40 FPA / g dry matter, 60 FPA / g dry matter, 80 FPA / g dry matter, 100 FPA / g dry matter).

[0029] In some embodiments, the temperature of the enzymatic hydrolysis is 40 - 60 °C, such as 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, 52 °C, 54 °C, 56 °C, 58 °C, 60 °C.

[0030] In some embodiments, the temperature of the enzymatic hydrolysis is 48 - 52 °C.

[0031] In some embodiments, the enzymatic hydrolysis time is 48 - 72 h, such as 50 h, 55 h, 60 h, 65 h, 70 h.

[0032] In some embodiments, the method further includes: fermenting the enzymatic hydrolysis product to obtain a fermentation broth, and distilling the fermentation broth to obtain ethanol with a content of 50% - 60% (w / w) and a distillation substrate. The distillation substrate includes macromolecular compounds such as saccharide polymers, inorganic substances, and proteins that are not easily distilled off.

[0033] In some embodiments, the fermentation step includes: introducing the enzymatic hydrolysis product into a fermentation tank, adding yeast, and fermenting at a temperature below 30 °C for 24 - 50 hours to obtain the fermentation broth.

[0034] In some embodiments, the ethanol content in the fermentation broth is 6 - 6.5% (w / w), such as 6% (w / w), 6.1% (w / w), 6.2% (w / w), 6.3% (w / w), 6.4% (w / w), 6.5% (w / w).

[0035] In some embodiments, the distillation substrate is filtered to obtain a filtrate and a filter cake. The filtrate is concentrated and then subjected to a cracking activation reaction with the filter cake to obtain solid fulvic acid or potassium fulvate.

[0036] In some embodiments, an activator is used in the cracking activation reaction.

[0037] In some embodiments, the activator is selected from one or more combinations of ammonium sulfite, potassium sulfite, potassium hydroxide, ammonium persulfate, potassium persulfate, or ammonia water.

[0038] In some embodiments, the addition amount of the activator is 3% - 20% of the dry basis mass of the distillation substrate, such as 3%, 5%, 7%, 9%, 11%, 13%, 15%, 20%.

[0039] In some embodiments, before the cooking treatment, the straw is pretreated, and the pretreatment includes dust removal, impurity removal, cleaning, and rubbing of the straw.

[0040] In some embodiments, the solid-liquid separation is performed using a mechanical separation device, such as a chamber diaphragm filter press.

[0041] By subjecting straw and a catalyst to a cooking treatment, while decomposing the three components of straw, fulvic acid is produced by the reaction of lignin. Fulvic acid can be produced in one step without a washing solution and with a relatively high content. At the same time, the subsequent enzymatic hydrolysis and fermentation have good effects, high sugar yield, and high sugar alcohol conversion rate.

[0042] The process flow of the present invention is simple and easy to achieve large-scale production. The products prepared by the method of the present invention have high value. Ethanol can be prepared into fuel ethanol through rectification and dehydration; the by-products, liquid fulvic acid, solid fulvic acid or potassium fulvate have high added value and can promote plant growth and development, improve soil, etc. Moreover, the present invention realizes the high-value utilization of straw in all aspects, with low overall production cost and high economic benefits of the products. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the drawings. The specific embodiments described herein are only used to explain the present invention and do not constitute any limitation to the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure. Such structures and technologies have also been described in many publications.

[0045] In the present invention, except for the enzymatic hydrolysis rate, "%" refers to mass percentage or weight percentage.

[0046] The water content of the straw in the embodiments of the present invention is 12 wt%.

[0047] The following embodiments of the present invention are all prepared according to the Figure 1 shown process:

[0048] S1. After the straw is decontaminated, dedusted, cleaned and rubbed, the treated straw is put into a digester, and water, ammonium sulfite and a catalyst are added for cooking treatment. After the reaction, the material is discharged under pressure. The material is subjected to solid-liquid separation by a chamber diaphragm filter press to obtain straw residue and filtrate. The filtrate can be refined and concentrated by an MVR concentrator to obtain liquid fulvic acid.

[0049] S2. The straw residue is treated by a washing system

[0050] The washing system includes a washing device, a solid-liquid separator and an extrusion device. The straw residue is sent to the washing device for washing to obtain straw residue and washing liquid. In the washing device, the mass ratio of the straw residue to water is 1:(1-5);

[0051] S3. The straw residue is sent to an enzymatic hydrolysis tank for enzymatic hydrolysis.

[0052] Feed the straw residue into the enzymatic hydrolysis tank; a complex enzyme is also added to the enzymatic hydrolysis tank; the solid content of the slurry in the enzymatic hydrolysis tank is 15-25%, the enzyme in the enzymatic hydrolysis tank is selected from one or more of cellulase, xylanase or cellobiase, the addition amount of cellulase is 0-100 FPA / g dry matter, the addition amount of xylanase is 0-3000 U / g dry matter, the addition amount of cellobiase is 2-100 U / g dry matter, the temperature is 50 °C (±2 °C), the stirring rate is 0.6-2 rpm, the enzymatic hydrolysis time is 48-72 h, and the solid-liquid separation form is a mechanical filtration device.

[0053] S4. Feed the enzymatic hydrolysate obtained in S3 into the fermentation tank, add a strain for fermentation to obtain a fermentation broth with an ethanol content of 6-6.5% (w / w).

[0054] S5. Feed the fermentation broth obtained in S4 into a distillation device for distillation to obtain an ethanol product with a content of 50-60% and a distillation substrate. The distillation substrate goes to a filtration device, the filtrate is concentrated and then reacts with the filter cake through a cracking and activation device, and the reaction product is dried to obtain a solid fulvic acid product.

[0055] The distillation device includes general devices commonly used in traditional chemical industries such as a distillation column and a distillation kettle.

[0056] The method for sampling and detecting the filtrate in the embodiment of the present invention is as follows:

[0057] 1. The execution standard for the determination of fulvic acid content: HG / T 5334-2018

[0058] 2. Determination of dry matter content: drying loss method (cited standard: NY / T 302):

[0059] Place the aluminum box with the lid placed obliquely in an electrothermal blast drying oven at 100-105 °C and bake for 30 min. Take it out, cover it, transfer it to a desiccator and balance for 20 min, then take it out and weigh. Bake for another 30 min and weigh under the same conditions until the difference in mass between two weighings does not exceed 1 mg, which is the constant weight. Weigh about 5 g of the sample accurately to 0.001 g, spread it flat in the known constant weight aluminum box, cover the lid, and transfer it to an electrothermal blast drying oven preheated to 105 °C (the aluminum box should be close to the horizontal position of the thermometer mercury bulb and not close to the inner wall of the oven). Open the lid of the box and place it obliquely, then close the oven door. Dry at 105 ± 2 °C for 8 h. Cover the lid of the box, take it out, transfer it to a desiccator and balance for 30 min, then take it out and weigh. The moisture content is expressed as a mass percentage (%), and is calculated according to the following formula:

[0060]

[0061] In the formula: m1 ---- the mass of the air-dried sample and the aluminum box, g;

[0062] m2 ---- Mass of the dried sample and aluminum box, g;

[0063] m0 ---- Mass of the aluminum box, g.

[0064] The dry matter content is equal to 100% - moisture (air-dried basis).

[0065] 3. Enzymatic hydrolysis sugar concentration: (Fehling's method)

[0066] Main reagents and solutions: (1) Fehling's solution A: Weigh 30.4 g of copper sulfate and 0.1 g of methylene blue, dissolve in distilled water and make up to 2000 mL; (2) Fehling's solution B: Dissolve 150 g of sodium hydroxide, 100 g of potassium sodium tartrate, and 8 g of potassium ferrocyanide in distilled water and make up to 2000 mL; (3) Glucose standard solution (0.1%): Accurately weigh 2.000 g of anhydrous glucose, dissolve in water, add 10 mL of concentrated hydrochloric acid, and make up to 2000 mL with distilled water; (4) Sulfuric acid: Analytical pure (98%).

[0067] Accurately weigh 1.0 g of the sample (accurate to 0.0001 g) into a 250 mL volumetric flask, dilute with water to the mark. Take 1.0 g of the above dilution (accurate to 0.0001 g) into a conical flask containing 5 mL each of solution A and solution B, add an appropriate amount of 0.1% (w / w) glucose standard solution, shake well, heat on an electric furnace, control the liquid in the flask to boil within 2 min and keep it slightly boiling, then titrate dropwise at a rate of 4 - 5 drops / s until the blue color disappears. The volume of the 0.1% glucose standard solution consumed after heating should not exceed 1 mL, and the titration process should not exceed 1 min, otherwise titrate again. Record the volume V1 of the sample solution consumed in the titration. The mixed sugar concentration W is calculated according to the formula:

[0068]

[0069] In the formula: V0 —— Volume of the glucose standard titration solution consumed in the blank test, unit is milliliter (mL);

[0070] V1 —— Volume of the glucose standard titration solution consumed by the sample, unit is milliliter (mL);

[0071] C —— Concentration of the glucose standard titration solution, unit is (%)

[0072] M1 —— Mass of the sample for the first time, unit is gram (g);

[0073] M2 —— Mass of the sample for the second time, unit is gram (g).

[0074] Example 1

[0075] Pretreat wheat straw, including dust removal, impurity removal, cleaning, and rubbing, and then according to Figure 1For the process shown, 1.8 tons of pretreated wheat straw were put into a 20 m 3 cooking vessel, 3.4 tons of water, 8% (w / w) (128 kg) of ammonium sulfite and 0.1% (w / w) (1.6 kg) of ammonium persulfate were added. Cooking treatment was carried out at 150 °C and 0.6 MPa. After 2 hours of reaction, the material was discharged under pressure. The material was subjected to solid-liquid separation by a chamber diaphragm filter press to obtain straw residue and filtrate. The condition parameters of the above cooking treatment are shown in Table 1. After testing, in the straw residue, the dry matter concentration was 30.29% (w / w), cellulose was 44.36% (w / w), hemicellulose was 20.02% (w / w), and lignin was 18.76% (w / w); for the filtrate sampling test: the dry matter concentration was 11.19% (w / w), the fulvic acid concentration was 6.28% (w / w), and the fulvic acid content calculated on a dry basis was 56.12% (w / w). As shown in Table 2.

[0076] Using water as the washing liquid, the above-obtained straw residue was subjected to multi-stage countercurrent washing treatment and then put into an enzymatic hydrolysis tank. Cellulase at 30 FPA / g of dry matter, xylanase at 1000 U / g of dry matter, and cellobiase at 50 U / g of dry matter were added to the enzymatic hydrolysis tank. After maintaining at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, and 96 hours respectively, the sugar concentration was sampled and detected: the sugar concentration at 24 hours was 5.37%, and the enzymatic hydrolysis rate was calculated to be 52.46%; the sugar concentration at 48 hours was 7.43%, and the enzymatic hydrolysis rate was calculated to be 69.86%; the sugar concentration at 72 hours was 7.50%, and the enzymatic hydrolysis rate was calculated to be 73.26%; the sugar concentration at 96 hours was 7.32%, and the enzymatic hydrolysis rate was calculated to be 71.51%. As shown in Table 3.

[0077] The enzymatic hydrolysis product was put into a 10 m 3 fermentation tank and reacted at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth was detected by liquid chromatography to be 6.12%.

[0078] The above fermentation broth was preheated by a distillation tower preheater and then entered from the upper middle part of the distillation tower. Ethanol was collected by extraction from the distillation tower. The ethanol content was detected by liquid chromatography for sampling to be 51.30%. As shown in Table 5. After the waste liquid at the bottom of the tower was discharged from the bottom, it was subjected to plate and frame filtration. The filtrate was concentrated by a single-effect evaporator, and the concentrated filtrate was returned to be mixed with the filter cake. The obtained mixture was used to prepare solid fulvic acid.

[0079] Preparation of solid fulvic acid:

[0080] Take 50 kg of the above mixture and put it into the cracking and activation reactor. Add 3% (w / w) potassium hydroxide, 0.2% (w / w) ammonium persulfate and 100 kg of water respectively, and react at 150 °C for 2 hours. After completion, take samples for detection and analysis: the dry matter concentration is 21.21% (w / w), the fulvic acid is 7.65% (w / w), and the fulvic acid content calculated on a dry basis is 36.07% (w / w). The above cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0081] Example 2

[0082] Pretreat wheat straw, including dust removal, impurity removal, cleaning and rubbing, and then according to the Figure 1 shown process, put 1.8 tons of pretreated wheat straw into a 20 m 3 digester, add 3.4 tons of water, 10% (w / w) (158 kg) ammonium sulfite and 0.1% (w / w) (1.6 kg) ammonium persulfate, and carry out cooking treatment at 150 °C and 0.6 MPa for 2 hours. After the reaction, discharge the material under pressure. The material is separated into solid and liquid by a chamber diaphragm filter press to obtain straw residue and filtrate. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in the straw residue, the dry matter concentration is 38.11% (w / w), the cellulose is 44.70% (w / w), the hemicellulose is 21.81% (w / w), and the lignin is 11.91% (w / w); for the filtrate sample detection: the dry matter concentration is 11.80% (w / w), the fulvic acid concentration is 6.65% (w / w), and the fulvic acid content calculated on a dry basis is 56.36% (w / w). As shown in Table 2.

[0083] Using water as the washing liquid, after subjecting the above-obtained straw residue to multi-stage countercurrent washing treatment, put it into an enzymatic hydrolysis tank, and add cellulase at 30 FPA / g dry matter, xylanase at 1000 U / g dry matter and cellobiase at 50 U / g dry matter to the enzymatic hydrolysis tank. Maintain at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, 96 hours and then take samples to detect the sugar concentration respectively: the sugar concentration at 24 hours is 6.75%, and the calculated enzymatic hydrolysis rate is 89.86%; the sugar concentration at 48 hours is 6.90%, and the calculated enzymatic hydrolysis rate is 91.92%; the sugar concentration at 72 hours is 6.98%, and the calculated enzymatic hydrolysis rate is 92.97%; the sugar concentration at 96 hours is 6.76%, and the calculated enzymatic hydrolysis rate is 90.04%.

[0084] Put the enzymatic hydrolysis product into a 10 m 3 fermentation tank and react at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.27%.

[0085] The above fermentation broth is preheated in a distillation column preheater and then enters the middle-upper part of the distillation column. Ethanol is collected by distillation from the distillation column. The ethanol content is detected by liquid chromatography analysis of the sample, and it is 51.78%, as shown in Table 5. After the waste liquid at the bottom of the column is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid.

[0086] Solid fulvic acid is prepared in the manner of Example 1. After the reaction ends, a sample is taken for detection and analysis: the dry matter concentration is 32.90% (w / w), the fulvic acid is 10.22% (w / w), and the fulvic acid content calculated on a dry basis is 31.06% (w / w). The above-mentioned pyrolysis activation condition parameters and the fulvic acid content detection data are shown in Table 4.

[0087] Example 3

[0088] The wheat straw is pretreated, including dust removal, impurity removal, cleaning, and rubbing, and then according to the Figure 1 shown process, 1.8 tons of pretreated wheat straw is put into a 20m 3 cooking vessel, 3.4 tons of water, 12% (w / w) (190 kg) of ammonium sulfite, and 0.1% (w / w) (1.6 kg) of ammonium persulfate are added. The cooking treatment is carried out at 150 °C and 0.6 MPa for 2 hours. After the reaction, the material is discharged under pressure. The material is separated into solid and liquid by a chamber diaphragm filter press to obtain straw residue and filtrate. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in the straw residue, the dry matter concentration is 28.27% (w / w), the cellulose is 41.75% (w / w), the hemicellulose is 19.99% (w / w), and the lignin is 11.72% (w / w); for the filtrate sample detection: the dry matter concentration is 11.97% (w / w), the fulvic acid concentration is 7.58% (w / w), and the fulvic acid content calculated on a dry basis is 63.32% (w / w). As shown in Table 2.

[0089] Using water as the washing liquid, the obtained straw residue is subjected to multi-stage countercurrent washing treatment and then put into an enzymatic hydrolysis tank. 30 FPA / g of dry matter of cellulase, 1000 U / g of dry matter of xylanase, and 50 U / g of dry matter of cellobiase are respectively added. After maintaining at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, and 96 hours, the sugar concentration is respectively sampled and detected: the sugar concentration at 24 hours is 8.36%, and the enzymatic hydrolysis rate is calculated to be 79.05%; the sugar concentration at 48 hours is 9.50%, and the enzymatic hydrolysis rate is calculated to be 89.83%; the sugar concentration at 72 hours is 9.95%, and the enzymatic hydrolysis rate is calculated to be 94.09%; the sugar concentration at 96 hours is 9.75%, and the enzymatic hydrolysis rate is calculated to be 92.20%.

[0090] The enzymatic hydrolysis product is put into a 10m 3In the fermenter, the reaction was carried out at 30 °C for 48 hours to obtain the fermentation broth. The ethanol content in the fermentation broth was detected by liquid chromatography to be 6.33%.

[0091] The above fermentation broth was preheated through a distillation column preheater and then entered from the upper middle part of the distillation column. Ethanol was collected by sampling from the distillation column. The ethanol content detected by liquid chromatography analysis was 52.24%, as shown in Table 5. After the waste liquid at the bottom of the column was discharged from the bottom, it was filtered by a plate and frame filter press. The filtrate was concentrated by a single-effect evaporator, and after concentration, it was returned to be mixed with the filter cake. The obtained mixture was used to prepare solid fulvic acid. Solid fulvic acid was prepared in the manner of Example 1. After the reaction ended, samples were taken for detection and analysis: the dry matter concentration was 35.90%, the fulvic acid was 8.91%, and the fulvic acid content calculated on a dry basis was 32.21%. The above cracking activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0092] Example 4

[0093] The wheat straw was pretreated, including dust removal, impurity removal, cleaning, and rubbing, and then according to the Figure 1 shown process, 1.8 tons of pretreated wheat straw was put into a 20 m 3 cooking vessel, 3.4 tons of water, 14% (w / w) (221 kg) of ammonium sulfite, and 0.1% (w / w) (1.6 kg) of ammonium persulfate were added. The cooking treatment was carried out at 150 °C and 0.6 MPa. After 2 hours of reaction, the material was discharged under pressure. The solid-liquid separation of the material was carried out by a chamber diaphragm filter press to obtain straw residue and filtrate. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in the straw residue, the dry matter concentration was 36.71% (w / w), the cellulose was 44.90% (w / w), the hemicellulose was 17.88% (w / w), and the lignin was 19.07% (w / w); for the filtrate sampling detection: the dry matter concentration was 15.49% (w / w), the fulvic acid concentration was 9.56% (w / w), and the fulvic acid content calculated on a dry basis was 61.72% (w / w). As shown in Table 2.

[0094] Using water as the washing liquid, the above obtained straw residue was subjected to multi-stage countercurrent washing treatment and then put into an enzymatic hydrolysis tank. Cellulase at 30 FPA / g dry matter, xylanase at 1000 U / g dry matter, and cellobiase at 50 U / g dry matter were added to the enzymatic hydrolysis tank. After maintaining at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, and 96 hours, samples were taken to detect the sugar concentration respectively: the sugar concentration at 24 hours was 6.75%, and the enzymatic hydrolysis rate was calculated to be 89.86%; the sugar concentration at 48 hours was 6.90%, and the enzymatic hydrolysis rate was calculated to be 91.92%; the sugar concentration at 72 hours was 6.98%, and the enzymatic hydrolysis rate was calculated to be 92.97%; the sugar concentration at 96 hours was 6.76%, and the enzymatic hydrolysis rate was calculated to be 90.04%.

[0095] The enzymatic hydrolysis product was put into a 10 m3 In the fermenter, the reaction was carried out at 30 °C for 48 hours to obtain the fermentation broth. The ethanol content in the fermentation broth was detected by liquid chromatography to be 6.34%.

[0096] The above fermentation broth was preheated by a distillation column preheater and then entered from the upper middle part of the distillation column. Ethanol was collected by sampling from the distillation column. The ethanol content was detected by liquid chromatography analysis to be 53.09%, as shown in Table 5. After the waste liquid at the bottom of the column was discharged from the bottom, it was filtered by a plate and frame filter press. The filtrate was concentrated by a single-effect evaporator, and after concentration, it was returned to be mixed with the filter cake. The obtained mixture was used to prepare solid fulvic acid. Solid fulvic acid was prepared in the manner of Example 1. After the reaction was completed, samples were taken for detection and analysis: the dry matter concentration was 29.95%, the fulvic acid was 10.62%, and the fulvic acid content calculated on a dry basis was 35.45%. The above cracking activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0097] Example 5

[0098] The wheat straw was pretreated, including dust removal, impurity removal, cleaning, and rubbing, and then according to the Figure 1 shown process, 1.8 tons of pretreated straw was put into a 20 m 3 cooking vessel, 3.4 tons of water, 15% (w / w) (238 kg) of ammonium sulfite, and 0.1% (w / w) (1.6 kg) of ammonium persulfate were added. The cooking treatment was carried out at 150 °C and 0.6 MPa for 2 hours. After the reaction, the material was discharged under pressure. The solid-liquid separation of the material was carried out by a chamber diaphragm filter press to obtain straw residue and filtrate. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in the straw residue, the dry matter concentration was 26.80% (w / w), the cellulose was 47.01% (w / w), the hemicellulose was 11.69% (w / w), and the lignin was 17.65% (w / w); for the filtrate sampling detection: the dry matter concentration was 10.13% (w / w), the fulvic acid concentration was 6.29%, and the fulvic acid content calculated on a dry basis was 62.09% (w / w). As shown in Table 2.

[0099] Using water as the washing liquid, the above-obtained straw residue was subjected to multi-stage countercurrent washing treatment and then put into an enzymatic hydrolysis tank. Cellulase at 30 FPA / g dry matter, xylanase at 1000 U / g dry matter, and cellobiase at 50 U / g dry matter were added to the enzymatic hydrolysis tank. After maintaining at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, and 96 hours, samples were taken to detect the sugar concentration respectively: the sugar concentration at 24 hours was 8.30%, and the enzymatic hydrolysis rate was calculated to be 81.54%; the sugar concentration at 48 hours was 9.75%, and the enzymatic hydrolysis rate was calculated to be 95.78%; the sugar concentration at 72 hours was 10.03%, and the enzymatic hydrolysis rate was calculated to be 98.53%; the sugar concentration at 96 hours was 9.95%, and the enzymatic hydrolysis rate was calculated to be 97.76%.

[0100] Put the enzymatic hydrolysate into 10 m 3 fermenter and react at 30 °C for 48 hours to obtain the fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.30%.

[0101] The above fermentation broth is preheated by a distillation tower preheater and then enters from the upper middle part of the distillation tower. Ethanol is collected by sampling from the distillation tower. The ethanol content is detected by liquid chromatography analysis to be 52.99%, as shown in Table 5. After the waste liquid at the bottom of the tower is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Prepare solid fulvic acid in the manner of Example 1. After the reaction is completed, samples are taken for detection and analysis: the dry matter concentration is 33.37% (w / w), the fulvic acid is 11.48% (w / w), and the fulvic acid content calculated on a dry basis is 34.40% (w / w). The above cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0102] Example 6

[0103] Different from Example 3, the straw is pre-treated rice straw, and the cooking temperature is 160 °C, the pressure is 0.7 MPa. After reacting for 2 hours, the material is discharged under pressure. The solid-liquid separation of the material is carried out by a chamber diaphragm filter press to obtain straw residue and filtrate. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in the straw residue, the dry matter concentration is 29.93% (w / w), the cellulose is 43.39% (w / w), the hemicellulose is 19.95% (w / w), and the lignin is 14.51% (w / w); the filtrate is sampled and detected: the dry matter concentration is 11.58% (w / w), the fulvic acid concentration is 7.50% (w / w), and the fulvic acid content calculated on a dry basis is 64.77% (w / w). As shown in Table 2.

[0104] Using water as the washing liquid, the above-obtained straw residue is subjected to multi-stage countercurrent washing treatment and then put into an enzymatic hydrolysis tank. Add cellulase at 30 FPA / g dry matter, xylanase at 1000 U / g dry matter, and cellobiase at 50 U / g dry matter to the enzymatic hydrolysis tank. Samples are taken for sugar concentration detection after maintaining at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, and 96 hours respectively: the sugar concentration at 24 hours is 7.42%, and the calculated enzymatic hydrolysis rate is 89.39%; the sugar concentration at 48 hours is 7.84%, and the calculated enzymatic hydrolysis rate is 94.47%; the sugar concentration at 72 hours is 8.14%, and the calculated enzymatic hydrolysis rate is 98.03%; the sugar concentration at 96 hours is 8.02%, and the calculated enzymatic hydrolysis rate is 96.65%.

[0105] Put the enzymatic hydrolysate into 10 m 3 fermenter and react at 30 °C for 48 hours to obtain the fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.35%.

[0106] The above fermentation broth is preheated by a distillation column preheater and then enters the middle-upper part of the distillation column. Ethanol is collected by distillation from the distillation column. The ethanol content is detected by liquid chromatography analysis of the sample, which is 53.53%, as shown in Table 5. After the waste liquid at the bottom of the column is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Solid fulvic acid is prepared in the manner of Example 1. After the reaction is completed, a sample is taken for detection and analysis: the dry matter concentration is 34.47% (w / w), the fulvic acid is 13.44% (w / w), and the fulvic acid content calculated on a dry basis is 38.98% (w / w). The above-mentioned pyrolysis activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0107] Example 7

[0108] Different from Example 6, the cooking temperature is 170 °C and the pressure is 0.8 MPa. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in its straw residue, the dry matter concentration is 52.77% (w / w), the cellulose is 40.09% (w / w), the hemicellulose is 18.61% (w / w), and the lignin is 10.33% (w / w); the filtrate is sampled for detection: the dry matter concentration is 11.87% (w / w), the fulvic acid concentration is 7.85% (w / w), and the fulvic acid content calculated on a dry basis is 66.13% (w / w). As shown in Table 2.

[0109] The enzymatic hydrolysis treatment is carried out in the manner of Example 1 and the sugar concentration is detected by sampling: the sugar concentration at 24 hours is 6.94%, and the enzymatic hydrolysis rate is calculated to be 89.11%; the sugar concentration at 48 hours is 7.57%, and the enzymatic hydrolysis rate is calculated to be 97.20%; the sugar concentration at 72 hours is 7.42%, and the enzymatic hydrolysis rate is calculated to be 95.32%.

[0110] The enzymatic hydrolysis product is put into a 10 m 3 fermentation tank and reacted at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.28%.

[0111] The above fermentation broth is preheated by a distillation column preheater and then enters the middle-upper part of the distillation column. Ethanol is collected by distillation from the distillation column. The ethanol content is detected by liquid chromatography analysis of the sample, which is 53.47%, as shown in Table 5. After the waste liquid at the bottom of the column is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Solid fulvic acid is prepared in the manner of Example 1. After the reaction is completed, a sample is taken for detection and analysis: the dry matter concentration is 36.36% (w / w), the fulvic acid is 12.81% (w / w), and the fulvic acid content calculated on a dry basis is 35.22% (w / w). The above-mentioned pyrolysis activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0112] Example 8

[0113] Different from Example 6, the cooking temperature is 180 °C and the pressure is 1.0 MPa. The condition parameters of the above cooking treatment are shown in Table 1. After testing, in the straw residue, the dry matter concentration is 27.90% (w / w), cellulose is 45.76% (w / w), hemicellulose is 18.26% (w / w), and lignin is 12.27% (w / w); for the filtrate sampling test: the dry matter concentration is 11.04% (w / w), the fulvic acid concentration is 7.45% (w / w), and the fulvic acid content calculated on a dry basis is 67.48% (w / w). As shown in Table 2.

[0114] Perform enzymatic hydrolysis treatment and sample for sugar concentration detection in the manner of Example 1: the sugar concentration at 24 hours is 7.76%, and the calculated enzymatic hydrolysis rate is 92.08%; the sugar concentration at 48 hours is 8.33%, and the calculated enzymatic hydrolysis rate is 98.84%; the sugar concentration at 72 hours is 8.18%, and the calculated enzymatic hydrolysis rate is 97.07%.

[0115] Put the enzymatic hydrolysis product into a 10 m 3 fermentation tank and react at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.40%.

[0116] Preheat the above fermentation broth through the distillation tower preheater and then enter from the upper middle part of the distillation tower. Ethanol is collected from the distillation tower. The ethanol content is detected by liquid chromatography analysis of the sample to be 55.05%, as shown in Table 5. After the waste liquid at the bottom of the tower is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Prepare solid fulvic acid in the manner of Example 1. After the reaction ends, sample for detection and analysis: the dry matter concentration is 39.45% (w / w), fulvic acid is 14.24% (w / w), and the fulvic acid content calculated on a dry basis is 36.10% (w / w). The condition parameters of the above cracking and activation and the detection data of the fulvic acid content are shown in Table 4.

[0117] Example 9

[0118] Different from Example 6, the cooking temperature is 190 °C and the pressure is 1.2 MPa. The condition parameters of the above cooking treatment are shown in Table 1. After testing, in the straw residue, the dry matter concentration is 28.22% (w / w), cellulose is 46.54% (w / w), hemicellulose is 18.05% (w / w), and lignin is 10.96% (w / w); for the filtrate sampling test: the dry matter concentration is 12.26% (w / w), the fulvic acid concentration is 7.91% (w / w), and the fulvic acid content calculated on a dry basis is 64.52%. As shown in Table 2.

[0119] Perform enzymatic hydrolysis treatment and sample for detecting sugar concentration in the manner of Example 1: The sugar concentration at 24 hours is 7.39%, and the enzymatic hydrolysis rate is calculated to be 95.40%; the sugar concentration at 48 hours is 7.56%, and the enzymatic hydrolysis rate is calculated to be 97.56%; the sugar concentration at 72 hours is 7.15%, and the enzymatic hydrolysis rate is calculated to be 92.30%.

[0120] Put the enzymatic hydrolysis product into a 10 m 3 fermentation tank and react at 30 °C for 48 hours to obtain fermentation broth. Detect the ethanol content in the fermentation broth by liquid chromatography to be 6.22%.

[0121] Feed the above fermentation broth into the distillation column after preheating in the preheater of the distillation column and enter from the upper middle part of the distillation column. Ethanol is collected by sampling from the distillation column. The ethanol content detected by liquid chromatography analysis of the sample is 53.62%, as shown in Table 5. After the waste liquid at the bottom of the column is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to make solid fulvic acid. Prepare fulvic acid in the manner of Example 1. After the reaction is completed, sample for detection and analysis: the dry matter concentration is 29.87% (w / w), the fulvic acid is 10.18% (w / w), and the fulvic acid content calculated on a dry basis is 34.09% (w / w). The above-mentioned cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0122] Example 10

[0123] The difference from Example 6 is that the raw material is pretreated corn straw, and the weight ratio of corn straw to water is 1:2.5, that is, 4.5 tons of water is added to 1.8 tons of corn straw. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in its straw residue, the dry matter concentration is 45.06% (w / w), the cellulose is 49.12% (w / w), the hemicellulose is 15.66% (w / w), and the lignin is 13.99% (w / w); for the filtrate sample detection: the dry matter concentration is 11.46% (w / w), the fulvic acid concentration is 7.75% (w / w), and the fulvic acid content calculated on a dry basis is 67.63% (w / w). As shown in Table 2.

[0124] Perform enzymatic hydrolysis treatment and sample for detecting sugar concentration in the manner of Example 1: The sugar concentration at 24 hours is 7.66%, and the enzymatic hydrolysis rate is calculated to be 88.00%; the sugar concentration at 48 hours is 8.17%, and the enzymatic hydrolysis rate is calculated to be 93.91%; the sugar concentration at 72 hours is 8.54%, and the enzymatic hydrolysis rate is calculated to be 98.12%; the sugar concentration at 96 hours is 8.38%, and the enzymatic hydrolysis rate is calculated to be 96.30%.

[0125] Put the enzymatic hydrolysis product into a 10 m 3 fermentation tank and react at 30 °C for 48 hours to obtain fermentation broth. Detect the ethanol content in the fermentation broth by liquid chromatography to be 6.31%.

[0126] The above fermentation broth is preheated through a distillation column preheater and then enters the middle-upper part of the distillation column. Ethanol is collected by drawing from the distillation column. The ethanol content is detected by liquid chromatography analysis of the sample, and it is 54.80%. After the waste liquid at the bottom of the column is discharged from the bottom, it is filtered by a plate-and-frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Solid fulvic acid is prepared in the manner of Example 1. After the reaction ends, a sample is taken for detection and analysis: the dry matter concentration is 34.98% (w / w), the fulvic acid is 13.21% (w / w), and the fulvic acid content calculated on a dry basis is 37.77% (w / w). The above-mentioned condition parameters of cracking and activation and the detection data of fulvic acid content are shown in Table 4.

[0127] Example 11

[0128] Different from Example 10, the weight ratio of corn straw to water is 1:3, that is, 5.4 tons of water is added to 1.8 tons of corn straw. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in the straw residue, the dry matter concentration is 28.86% (w / w), the cellulose is 47.39% (w / w), the hemicellulose is 17.56% (w / w), and the lignin is 11.55% (w / w); for the filtrate sample detection: the dry matter concentration is 12.79% (w / w), the fulvic acid concentration is 9.00% (w / w), and the fulvic acid content calculated on a dry basis is 70.37% (w / w). As shown in Table 2.

[0129] The enzymatic hydrolysis treatment is carried out in the manner of Example 1 and a sample is taken to detect the sugar concentration: the sugar concentration at 24 hours is 8.01%, and the calculated enzymatic hydrolysis rate is 89.99%; the sugar concentration at 48 hours is 8.51%, and the calculated enzymatic hydrolysis rate is 95.61%; the sugar concentration at 72 hours is 8.75%, and the calculated enzymatic hydrolysis rate is 98.34%; the sugar concentration at 96 hours is 8.39%, and the calculated enzymatic hydrolysis rate is 94.25%.

[0130] The enzymatic hydrolysis product is put into a 10m 3 fermentation tank and reacted at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography and is 6.20%.

[0131] The above fermentation broth is preheated through a distillation column preheater and then enters the middle-upper part of the distillation column. Ethanol is collected by drawing from the distillation column. The ethanol content is detected by liquid chromatography analysis of the sample, and it is 55.10%. After the waste liquid at the bottom of the column is discharged from the bottom, it is filtered by a plate-and-frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Solid fulvic acid is prepared in the manner of Example 1. After the reaction ends, a sample is taken for detection and analysis: the dry matter concentration is 30.67% (w / w), the fulvic acid is 11.00% (w / w), and the fulvic acid content calculated on a dry basis is 35.85% (w / w). The above-mentioned condition parameters of cracking and activation and the detection data of fulvic acid content are shown in Table 4.

[0132] Example 12

[0133] Different from Example 10, the weight ratio of corn straw to water is 1:4, that is, 7.2 tons of water is added to 1.8 tons of corn straw. The condition parameters of the above cooking treatment are shown in Table 1. After testing, in the straw residue, the dry matter concentration is 33.99% (w / w), cellulose is 48.24% (w / w), hemicellulose is 17.89% (w / w), and lignin is 11.73% (w / w); for the filtrate sampling and testing: the dry matter concentration is 10.27% (w / w), the fulvic acid concentration is 7.12% (w / w), and the fulvic acid content calculated on a dry basis is 69.33% (w / w). As shown in Table 2.

[0134] Perform enzymatic hydrolysis treatment and sample for sugar concentration detection in the manner of Example 1: the sugar concentration at 24 hours is 8.74%, and the calculated enzymatic hydrolysis rate is 90.22%; the sugar concentration at 48 hours is 9.14%, and the calculated enzymatic hydrolysis rate is 94.36%; the sugar concentration at 72 hours is 9.48%, and the calculated enzymatic hydrolysis rate is 97.85%; the sugar concentration at 96 hours is 8.55%, and the calculated enzymatic hydrolysis rate is 88.27%.

[0135] Put the enzymatic hydrolysis product into a 10m 3 fermentation tank and react at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.14%.

[0136] Preheat the above fermentation broth through a distillation tower preheater and then enter from the middle-upper part of the distillation tower. Ethanol is collected by sampling from the distillation tower, and the ethanol content is detected by liquid chromatography analysis to be 54.74%. After the waste liquid at the bottom of the tower is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and the concentrated filtrate is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Prepare solid fulvic acid in the manner of Example 1. After the reaction is completed, sample for detection and analysis: the dry matter concentration is 38.48% (w / w), fulvic acid is 14.30% (w / w), and the fulvic acid content calculated on a dry basis is 37.16% (w / w). The condition parameters of the above cracking and activation and the detection data of the fulvic acid content are shown in Table 4.

[0137] Example 13

[0138] Different from Example 10, the weight ratio of corn straw to water is 1:5, that is, 9 tons of water is added to 1.8 tons of corn straw. The condition parameters of the above cooking treatment are shown in Table 1. After testing, in the straw residue, the dry matter concentration is 32.54% (w / w), cellulose is 45.54% (w / w), hemicellulose is 19.09% (w / w), and lignin is 10.26% (w / w); for the filtrate sampling test: the dry matter concentration is 11.09% (w / w), the fulvic acid concentration is 6.80% (w / w), and the fulvic acid content calculated on a dry basis is 61.32% (w / w). As shown in Table 2.

[0139] Perform enzymatic hydrolysis treatment and sample for sugar concentration detection in the manner of Example 1: the sugar concentration at 24 hours is 7.53%, and the enzymatic hydrolysis rate is calculated to be 89.78%; the sugar concentration at 48 hours is 7.87%, and the enzymatic hydrolysis rate is calculated to be 93.89%; the sugar concentration at 72 hours is 8.13%, and the enzymatic hydrolysis rate is calculated to be 96.94%; the sugar concentration at 96 hours is 7.65%, and the enzymatic hydrolysis rate is calculated to be 91.19%.

[0140] Put the enzymatic hydrolysis product into a 10m 3 fermentation tank and react at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.09%.

[0141] Preheat the above fermentation broth through a distillation tower preheater and then enter from the middle and upper part of the distillation tower. Ethanol is collected by sampling from the distillation tower, and the ethanol content is detected by liquid chromatography analysis to be 54.96%. After the waste liquid at the bottom of the tower is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and the concentrated filtrate is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Prepare solid fulvic acid in the manner of Example 1. After the reaction is completed, sample for detection and analysis: the dry matter concentration is 29.88% (w / w), fulvic acid is 10.31% (w / w), and the fulvic acid content calculated on a dry basis is 34.52% (w / w). The condition parameters of the above cracking and activation and the detection data of the fulvic acid content are shown in Table 4.

[0142] Example 14

[0143] Different from Example 10, the raw material straw is cotton straw (the lignin content is 25.50% of the dry basis mass of the straw), and the cooking reaction duration is 3 hours. The condition parameters of the above cooking treatment are shown in Table 1. After testing, in the straw residue, the dry matter concentration is 44.46% (w / w), cellulose is 46.97% (w / w), hemicellulose is 6.28% (w / w), and lignin is 28.41% (w / w); for the filtrate sampling test: the dry matter concentration is 11.61% (w / w), the fulvic acid concentration is 6.42% (w / w), and the fulvic acid content calculated on a dry basis is 60.51% (w / w). As shown in Table 2.

[0144] The enzymatic hydrolysis treatment was carried out in the same manner as in Example 1 and samples were taken for sugar concentration detection: the sugar concentration at 24 hours was 8.88%, and the enzymatic hydrolysis rate was calculated to be 94.50%; the sugar concentration at 48 hours was 9.24%, and the enzymatic hydrolysis rate was calculated to be 98.32%; the sugar concentration at 72 hours was 8.77%, and the enzymatic hydrolysis rate was calculated to be 93.33%; the sugar concentration at 96 hours was 8.43%, and the enzymatic hydrolysis rate was calculated to be 89.70%.

[0145] The enzymatic hydrolysis product was put into a 10 m 3 fermentation tank and reacted at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth was detected by liquid chromatography to be 6.38%.

[0146] The above fermentation broth was preheated in a distillation tower preheater and then entered from the upper middle part of the distillation tower. Ethanol was collected from the distillation tower. Samples were taken and analyzed by liquid chromatography to detect the ethanol content to be 55.21%. After the waste liquid at the bottom of the tower was discharged from the bottom, it was pressure-filtered through a plate-and-frame filter. The filtrate was concentrated by a single-effect evaporator, and after concentration, it was returned to be mixed with the filter cake. The obtained mixture was used for the preparation of solid fulvic acid. The solid fulvic acid was prepared in the same manner as in Example 1. After the reaction ended, samples were taken for detection and analysis: the dry matter concentration was 30.87% (w / w), the fulvic acid was 10.93% (w / w), and the fulvic acid content calculated on a dry basis was 35.42% (w / w). The above cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0147] Example 15

[0148] The difference from Example 14 was that the cooking reaction duration was 4 hours. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in its straw residue, the dry matter concentration was 51.09% (w / w), the cellulose was 47.77% (w / w), the hemicellulose was 8.28% (w / w), and the lignin was 26.85% (w / w); for the filtrate sample detection: the dry matter concentration was 9.53% (w / w), the fulvic acid concentration was 5.20% (w / w), and the fulvic acid content calculated on a dry basis was 54.46% (w / w). As shown in Table 2.

[0149] The enzymatic hydrolysis treatment was carried out in the same manner as in Example 1 and samples were taken for sugar concentration detection: the sugar concentration at 24 hours was 7.53%, and the enzymatic hydrolysis rate was calculated to be 73.28%; the sugar concentration at 48 hours was 7.88%, and the enzymatic hydrolysis rate was calculated to be 76.68%; the sugar concentration at 72 hours was 8.70%, and the enzymatic hydrolysis rate was calculated to be 84.66%; the sugar concentration at 96 hours was 8.10%, and the enzymatic hydrolysis rate was calculated to be 78.82%.

[0150] The enzymatic hydrolysis product was put into a 10 m 3 fermentation tank and reacted at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth was detected by liquid chromatography to be 6.01%.

[0151] The above fermentation broth is preheated by a distillation tower preheater and then enters from the middle-upper part of the distillation tower. Ethanol is collected by extraction from the distillation tower. Sampling is carried out and the ethanol content is detected by liquid chromatography analysis to be 51.17%. After the waste liquid at the bottom of the tower is discharged from the bottom, it is subjected to plate-and-frame filtration. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Solid fulvic acid is prepared in the manner of Example 1. After the reaction is completed, sampling is carried out for detection and analysis: the dry matter concentration is 33.86% (w / w), the fulvic acid is 12.28% (w / w), and the fulvic acid content calculated on a dry basis is 36.26% (w / w). The above-mentioned pyrolysis activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0152] Example 16

[0153] Different from Example 14, the cooking reaction duration is 0.5 hours. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in its straw residue, the dry matter concentration is 22.70% (w / w), the cellulose is 47.06% (w / w), the hemicellulose is 15.90% (w / w), and the lignin is 23.66% (w / w); for the filtrate sampling detection: the dry matter concentration is 5.01% (w / w), the fulvic acid concentration is 2.54% (w / w), and the fulvic acid content calculated on a dry basis is 49.94% (w / w). As shown in Table 2.

[0154] The enzymatic hydrolysis treatment is carried out in the manner of Example 1 and sampling is carried out to detect the sugar concentration: the sugar concentration at 24 hours is 4.75%, and the calculated enzymatic hydrolysis rate is 61.97%; the sugar concentration at 48 hours is 5.80%, and the calculated enzymatic hydrolysis rate is 75.66%; the sugar concentration at 72 hours is 6.55%, and the calculated enzymatic hydrolysis rate is 85.45%; the sugar concentration at 96 hours is 6.69%, and the calculated enzymatic hydrolysis rate is 87.34%.

[0155] The enzymatic hydrolysis product is put into a 10m 3 fermentation tank and reacted at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.27%.

[0156] The above fermentation broth is preheated by a distillation tower preheater and then enters from the middle-upper part of the distillation tower. Ethanol is collected by extraction from the distillation tower. Sampling is carried out and the ethanol content is detected by liquid chromatography analysis to be 50.08%. After the waste liquid at the bottom of the tower is discharged from the bottom, it is subjected to plate-and-frame filtration. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to make solid fulvic acid. Solid fulvic acid is prepared in the manner of Example 1. After the reaction is completed, sampling is carried out for detection and analysis: the dry matter concentration is 26.68% (w / w), the fulvic acid is 9.32% (w / w), and the fulvic acid content calculated on a dry basis is 34.93% (w / w). The above-mentioned pyrolysis activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0157] Example 17

[0158] Different from Example 10, the cooking reaction duration is 1.5 hours. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in its straw residue, the dry matter concentration is 33.76% (w / w), cellulose is 44.52% (w / w), hemicellulose is 14.64% (w / w), and lignin is 12.98% (w / w); for the filtrate sampling detection: the dry matter concentration is 10.72% (w / w), the fulvic acid concentration is 7.33% (w / w), and the fulvic acid content calculated on a dry basis is 68.38%. As shown in Table 2.

[0159] Perform enzymatic hydrolysis treatment and sample for sugar concentration detection in the manner of Example 1: the sugar concentration at 24 hours is 7.72%, and the enzymatic hydrolysis rate is calculated to be 86.63%; the sugar concentration at 48 hours is 8.41%, and the enzymatic hydrolysis rate is calculated to be 94.37%; the sugar concentration at 72 hours is 8.50%, and the enzymatic hydrolysis rate is calculated to be 95.38%; the sugar concentration at 96 hours is 8.21%, and the enzymatic hydrolysis rate is calculated to be 92.11%.

[0160] Put the enzymatic hydrolysis product into a 10m 3 fermentation tank and react at 30 °C for 48 hours to obtain a fermentation broth. The ethanol content in the fermentation broth is detected by liquid chromatography to be 6.31%.

[0161] Preheat the above fermentation broth through a distillation tower preheater and then enter from the upper middle part of the distillation tower. Ethanol is collected by sampling from the distillation tower, and the ethanol content is detected by liquid chromatography analysis to be 50.08%. After the waste liquid at the bottom of the tower is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and after concentration, it is returned to be mixed with the filter cake. The obtained mixture is used to prepare solid fulvic acid. Prepare fulvic acid in the manner of Example 1. After the reaction ends, sample for detection and analysis: the dry matter concentration is 34.87% (w / w), fulvic acid is 12.41% (w / w), and the fulvic acid content calculated on a dry basis is 35.60% (w / w). The condition parameters of the above cracking and activation and the detection data of the fulvic acid content are shown in Table 4.

[0162] Example 18

[0163] Different from Example 10, the cooking reaction catalyst is 0.2% (w / w) (3.2 kg) potassium persulfate. The condition parameters of the above cooking treatment are shown in Table 1. After detection, in its straw residue, the dry matter concentration is 46.23% (w / w), cellulose is 51.25% (w / w), hemicellulose is 12.63% (w / w), and lignin is 17.55% (w / w); for the filtrate sampling detection: the dry matter concentration is 10.98% (w / w), the fulvic acid concentration is 7.41% (w / w), and the fulvic acid content calculated on a dry basis is 67.45% (w / w). As shown in Table 2.

[0164] Perform enzymatic hydrolysis treatment and sampling for sugar concentration detection in the manner of Example 1: the sugar concentration at 24 hours is 6.21%, and the enzymatic hydrolysis rate is calculated to be 89.25%; the sugar concentration at 48 hours is 6.51%, and the enzymatic hydrolysis rate is calculated to be 93.60%; the sugar concentration at 72 hours is 6.80%, and the enzymatic hydrolysis rate is calculated to be 97.72%; the sugar concentration at 96 hours is 6.68%, and the enzymatic hydrolysis rate is calculated to be 96.00%.

[0165] Put the enzymatic hydrolysis product into a 10 m 3 fermentation tank and react at 30 °C for 48 hours to obtain a fermentation broth. Detect the ethanol content in the fermentation broth by liquid chromatography to be 6.28%.

[0166] Pass the above-mentioned fermentation broth through a distillation tower preheater for preheating and then enter from the upper middle part of the distillation tower. Ethanol is collected by sampling from the distillation tower. The ethanol content is detected by liquid chromatography analysis to be 57.89%. After the waste liquid at the bottom of the tower is discharged from the bottom, it is filtered by a plate and frame filter press. The filtrate is concentrated by a single-effect evaporator, and the concentrated filtrate is returned to be mixed with the filter cake. The obtained mixture is used for the preparation of solid fulvic acid. Prepare fulvic acid in the manner of Example 1. After the reaction is completed, sample for detection and analysis: the dry matter concentration is 32.19% (w / w), fulvic acid is 11.90% (w / w), and the fulvic acid content calculated on a dry basis is 36.97% (w / w). The above-mentioned cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0167] Example 19

[0168] Take 50 kg of the mixture after filtration treatment of the distillation substrate in Example 8 and put it into a cracking and activation reaction kettle. Add 5% (w / w) potassium hydroxide, 0.1% (w / w) ammonium persulfate and 100 kg of water into it respectively, and react at 150 °C for 2 hours. After completion, sample for detection and analysis: its dry matter concentration is 33.15% (w / w), fulvic acid is 13.34% (w / w), and the fulvic acid content calculated on a dry basis is 40.25% (w / w). The above-mentioned cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0169] Example 20

[0170] Take 50 kg of the mixture after filtration treatment of the distillation substrate in Example 8 and put it into a cracking and activation reaction kettle. Add 7% (w / w) potassium hydroxide and 100 kg of water into it respectively, and react at 150 °C for 2 hours. After completion, sample for detection and analysis: its dry matter concentration is 35.57% (w / w), fulvic acid is 15.07% (w / w), and the fulvic acid content calculated on a dry basis is 42.38% (w / w). The above-mentioned cracking and activation condition parameters and fulvic acid content detection data are shown in Table 4.

[0171] Example 21

[0172] Take 50 kg of the mixture after filtration treatment of the distillation substrate in Example 8, put it into a cracking and activation reactor, and respectively add 9% (w / w) of potassium sulfite, 2% (w / w) of ammonia water and 100 kg of water, and react at 150 °C for 2 hours. After completion, sample and test and analyze: its dry matter concentration is 29.02% (w / w), fulvic acid is 10.39% (w / w), and the fulvic acid content calculated on a dry basis is 35.79% (w / w). The above cracking and activation condition parameters and the fulvic acid content test data are shown in Table 4.

[0173] Example 22

[0174] Take 50 kg of the mixture after filtration treatment of the distillation substrate in Example 8, put it into a cracking and activation reactor, and respectively add 11% (w / w) of ammonium sulfite, 2% (w / w) of ammonia water and 100 kg of water, and react at 150 °C for 2 hours. After completion, sample and test and analyze: its dry matter concentration is 35.66% (w / w), fulvic acid is 16.01% (w / w), and the fulvic acid content calculated on a dry basis is 44.90% (w / w). The above cracking and activation condition parameters and the fulvic acid content test data are shown in Table 4.

[0175] Example 23

[0176] Take 50 kg of the mixture after filtration treatment of the distillation substrate in Example 8, put it into a cracking and activation reactor, and respectively add 13% (w / w) of ammonium sulfite, 0.3% (w / w) of potassium persulfate and 100 kg of water, and react at 150 °C for 2 hours. After completion, sample and test and analyze: its dry matter concentration is 30.99% (w / w), fulvic acid is 13.51% (w / w), and the fulvic acid content calculated on a dry basis is 43.58% (w / w). The above cracking and activation condition parameters and the fulvic acid content test data are shown in Table 4.

[0177] Example 24

[0178] Take 50 kg of the mixture after filtration treatment of the distillation substrate in Example 8, put it into a cracking and activation reactor, and respectively add 15% (w / w) of ammonium sulfite, 0.1% (w / w) of potassium persulfate and 100 kg of water, and react at 150 °C for 2 hours. After completion, sample and test and analyze: its dry matter concentration is 37.11% (w / w), fulvic acid is 16.80% (w / w), and the fulvic acid content calculated on a dry basis is 45.26% (w / w). The above cracking and activation condition parameters and the fulvic acid content test data are shown in Table 4.

[0179] Comparative Example 1

[0180] Pretreat wheat straw, including dust removal, impurity removal, cleaning, and rubbing, and then according to the Figure 1 shown process, add to 20 m 31.8 tons of pretreated wheat straw were put into a digester, 3.4 tons of water and 8% (w / w) ammonium sulfite were added, and cooking treatment was carried out at 150 °C and 0.6 MPa. After 2 hours of reaction, the material was discharged under pressure. The material was subjected to solid-liquid separation by a chamber diaphragm filter press to obtain straw residue and filtrate. After testing, in the straw residue, the dry matter concentration was 36.77% (w / w), cellulose was 40.68% (w / w), hemicellulose was 18.18% (w / w), and lignin was 24.28% (w / w); for the filtrate sampling test: the dry matter concentration was 6.64% (w / w), the fulvic acid concentration was 3.33% (w / w), and the fulvic acid content calculated on a dry basis was 50.15% (w / w). As shown in Table 2.

[0181] Using water as the washing liquid, the above-mentioned obtained straw residue was washed and then put into an enzymatic hydrolysis tank. Cellulase at 30 FPA / g dry matter, xylanase at 1000 U / g dry matter, and cellobiase at 50 U / g dry matter were added to the enzymatic hydrolysis tank. After maintaining at 50 °C (±2 °C) for 24 hours, 48 hours, 72 hours, and 96 hours respectively, the sugar concentration was sampled and detected: the sugar concentration at 24 hours was 5.28%, and the enzymatic hydrolysis rate was calculated to be 82.01%; the sugar concentration at 48 hours was 5.33%, and the enzymatic hydrolysis rate was calculated to be 82.79%; the sugar concentration at 72 hours was 6.01%, and the enzymatic hydrolysis rate was calculated to be 93.35%; the sugar concentration at 96 hours was 5.54%, and the enzymatic hydrolysis rate was calculated to be 86.05%.

[0182] Table 1

[0183]

[0184]

[0185] Table 2

[0186]

[0187] Table 3

[0188]

[0189]

[0190] Table 4

[0191]

[0192]

[0193] Table 5

[0194]

[0195]

[0196] According to the comparison between the examples and the comparative examples, it can be seen that in the present invention, the straw and the catalyst are subjected to cooking treatment. While decomposing the three components of the straw, fulvic acid is produced by the reaction of lignin, and fulvic acid can be produced in one step without a washing solution, and its content is higher than that of Comparative Example 1. At the same time, the subsequent enzymatic hydrolysis and fermentation have good effects, high sugar yield and high sugar alcohol conversion rate.

[0197] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for co-producing ethanol and fulvic acid from straw, comprising the following steps: Cook the straw in an aqueous ammonium sulfite solution with a catalyst, and then perform solid-liquid separation to obtain straw residue and filtrate; the filtrate contains fulvic acid. The catalyst is selected from one or more of persulfates, peroxides or nitrites.

2. The method according to claim 1, wherein The catalyst is selected from one or more of ammonium persulfate, potassium persulfate, peroxynitric acid or potassium nitrite; preferably, the dosage of the catalyst is 0.05-0.2% based on the dry weight of the straw.

3. The method according to claim 1 or 2, characterized in that, The temperature of the cooking treatment is 150°C to 190°C, preferably 160-180°C; and / or, the pressure of the cooking treatment is 0.6-1.2 MPa; and / or, the time of the cooking treatment is 0.6-4 hours, preferably 1-3 hours.

4. The method according to any one of claims 1 to 3, characterized in that The weight ratio of straw to the aqueous ammonium sulfite solution is 1:(1-5), preferably 1:(1.5-4); and / or the dosage of ammonium sulfite in the aqueous ammonium sulfite solution is 8%-15% based on the dry weight of the straw, preferably 10-12%.

5. The method according to any one of claims 1 to 4, characterized in that The straw is selected from one or more of wheat straw, rice straw, corn straw, sorghum straw, reed, giant reed or cotton straw.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: refining and concentrating the filtrate to obtain liquid fulvic acid; and / or The filtrate is dried to obtain a solid fulvic acid product; Preferably, the drying is spray drying.

7. The method according to any one of claims 1-6, characterized in that The method further includes: washing the straw residue, and then performing enzymatic hydrolysis to obtain an enzymatic hydrolysis product; Preferably, the enzyme used for the enzymatic hydrolysis is selected from one or more of cellulase, cellobiase or xylanase; Preferably, the addition amount of cellulase is 0-100 FPA / g dry matter, the addition amount of xylanase is 0-3000 U / g dry matter, and the addition amount of cellobiase is 2-100 U / g dry matter.

8. The method according to claim 7, wherein The method further includes: fermenting the enzymatic hydrolysis product to obtain a fermentation broth, and distilling the fermentation broth to obtain ethanol with a content of 50%-60% (w / w) and a distillation substrate; Preferably, the fermentation step includes: introducing the enzymatic hydrolysis product into a fermentation tank, adding yeast, and fermenting at 20-30°C for 24-50 hours to obtain the fermentation broth; preferably, the ethanol content in the fermentation broth is 6-6.5% (w / w).

9. The method according to claim 8, wherein Filter the distillation substrate to obtain a filtrate and a filter cake, and perform a cracking activation reaction on the filtrate after concentration and the filter cake to obtain solid fulvic acid or potassium fulvate; Preferably, the cracking activation reaction uses an activator, preferably, the activator is selected from one or more combinations of ammonium sulfite, potassium sulfite, potassium hydroxide, ammonium persulfate, potassium persulfate or ammonia water; preferably, the addition amount of the activator is 3%-20% of the dry basis mass of the distillation substrate.

10. The method according to any one of claims 1-9, characterized in that, Before performing the cooking treatment, pre-treat the straw, and the pre-treatment includes dust removal, impurity removal, cleaning and rubbing of the straw.

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