Modified filter aid, preparation method and filtration treatment method of straw cellulose enzymolysis liquid

Abstract

The application provides a modified filter aid, a preparation method and a filtration treatment method of straw cellulose enzymolysis liquid. The modified filter aid is prepared from a filter aid, lye and a silane coupling agent. The modified filter aid provided by the application can greatly accelerate the filtration efficiency and flux when added into high-viscosity enzymolysis liquid, and the filter aid is easy to recycle and can be recycled, and has good economic practicability.

Description

Technical Field

[0001] This invention relates to the field of biomass energy utilization technology, and more specifically, to a modified filter aid, its preparation method, and a filtration treatment method for straw cellulose enzymatic hydrolysate. Background Technology

[0002] Straw is a biomass resource with rapid regeneration and high yield, and it is also a widely distributed renewable biomass resource in nature. If straw can be utilized in a high-value manner, and crop straw can be degraded into sugar or other useful chemicals, it can not only alleviate the shortage of fossil energy such as coal, oil, and natural gas, but also avoid environmental pollution caused by burning straw.

[0003] In recent years, to improve the utilization rate of straw, the separation of its components has become a key research focus for its high-value utilization. The contents of cellulose, hemicellulose, and lignin in straw are 40-50%, 20-30%, and 10-15%, respectively. The key to the high-value utilization of straw lies in breaking down the cross-linked structure of these three components and separating and extracting cellulose, hemicellulose, and lignin. Cellulose and hemicellulose can be further enzymatically hydrolyzed to generate C5 and C6 sugars, which are industrially used for fermentation to produce various biomass chemicals such as ethanol, butanol, and lactic acid.

[0004] Currently, various methods are used for the enzymatic hydrolysis and saccharification of straw cellulose. However, during the enzymatic hydrolysis process, the viscosity of the hydrolysate continuously increases, and the particle size of the hydrolysate is small (1–10 μm). Under high viscosity, this significantly affects the filtration and centrifugation efficiency of the hydrolysate. In the solid-liquid separation process of the hydrolysate on an industrial scale, filtration and centrifugation of the solution are difficult, time-consuming, and energy-intensive. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a modified filter aid and its preparation method. The modified filter aid provided by this invention, when added to a high-viscosity solution, can significantly accelerate the filtration efficiency and throughput of the liquid.

[0006] Firstly, one of the objectives of this invention is to provide a modified filter aid, which is prepared by comprising a filter aid, alkali solution A, and a silane coupling agent, wherein the filter aid is selected from natural silica powder.

[0007] Preferably, the natural silica powder is selected from at least one of natural diatomaceous earth, perlite, and kaolin; more preferably, the particle size of the natural silica powder is 50 to 300 mesh.

[0008] Preferably, the alkali solution A is selected from an aqueous solution of an inorganic strong base; more preferably, the alkali solution A is selected from an aqueous solution of at least one base selected from sodium hydroxide and potassium hydroxide.

[0009] Preferably, the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N,N-diethyl-3-(trimethoxysilyl)propylamine, N,N-diethyl-3-(triethoxysilyl)propylamine, N1-(3-(trimethoxysilyl)propyl)ethane-1,2-diamine, and N1-(3-(triethoxysilyl)propyl)ethane-1,2-diamine.

[0010] Secondly, another objective of this invention is to provide a method for preparing the modified filter aid that is one of the objectives of this invention.

[0011] Specifically, the method includes the following steps:

[0012] The filter aid is washed with water to remove inorganic salts and impurities. Alkali solution A is added to adjust the pH. After the reaction is carried out with silane coupling agent, the modified filter aid is obtained after solid-liquid separation, solid phase washing and drying.

[0013] Furthermore, in the above steps, the pH is adjusted to 10-14 using alkaline solution A; the solid-liquid ratio of the added filter aid to the added alkaline solution A is 1 / 5-1 / 20; and the mass of the added silane coupling agent is 0.1-1% of the mass of the filter aid, preferably 0.5-1%.

[0014] Furthermore, after adjusting the pH with alkali solution A and adding a silane coupling agent, the reaction was carried out at room temperature for 1–2 hours.

[0015] Furthermore, a third objective of this invention is to provide a filtration treatment method for straw cellulose enzymatic hydrolysate using a modified filter aid, which is one of the objectives of this invention.

[0016] Specifically, one of the objectives of this invention is to modify the filter aid so as to promote solid-liquid separation of the filtrate; preferably, it can significantly accelerate the filtration efficiency of straw cellulose enzymatic hydrolysate, realize continuous operation of filtration and washing of enzymatic hydrolysate, extract lignin from the filter cake, and the filter aid can also be recycled, thus having good economic value.

[0017] It is worth mentioning that in conventional straw comprehensive utilization processes, the mixed sugar solution after straw cellulose is hydrolyzed by cellulase is usually filtered and the hydrolysate is washed before being sent to the subsequent stage for sugar solution fermentation. Therefore, the filtration efficiency of straw cellulose hydrolysate affects the efficiency of straw comprehensive utilization processes.

[0018] In this invention, a certain amount of modified filter aid is added to the straw cellulose enzymatic hydrolysate to accelerate filtration efficiency and throughput. The method for continuous filtration and washing of the modified filter aid-treated straw cellulose enzymatic hydrolysate includes the following steps:

[0019] Step 1: Add a modified filter aid to the straw cellulose enzymatic hydrolysate, then perform solid-liquid separation on the mixture, wash the filter residue, and collect the filtrate.

[0020] Step 2: Add the filter residue to alkaline solution B and heat to react. Filter again to obtain a solid phase of straw ash and filter aid and a liquid phase containing lignin.

[0021] Preferably, the specific details are as follows:

[0022] Step 1: After the straw raw material is completely enzymatically hydrolyzed, a certain amount of treated modified filter aid is added to the straw cellulose hydrolysate. The mixture is then continuously filtered through solid-liquid separation equipment such as belt filter or disc filter. The filtered residue is washed with water to remove residual sugar solution from the solid. The filtrate is collected for subsequent fermentation operations.

[0023] Step 2: Add the filter residue to alkaline solution B and heat to react. Filter again to obtain a solid phase of straw ash and filter aid, and a solution containing alkaline lignin.

[0024] Preferably, in step one, the amount of modified filter aid added is 1 / 10 to 1 / 50 of the liquid volume.

[0025] Preferably, in step two, the alkaline solution B is an aqueous solution of sodium hydroxide or potassium hydroxide; the solid-liquid ratio of the filter residue to the alkaline solution B is 1 / 5 to 1 / 20.

[0026] Preferably, in step two, the filter residue is in an alkaline solution, the pH of the reaction system is 12-14, the reaction temperature is 20-60°C, and the reaction time is 1-4 hours.

[0027] Furthermore, the straw ash and the solid phase of the filter aid can be used for the regeneration of the filter aid. Specifically, the regeneration method of the filter aid is to calcine the straw ash and the solid phase of the filter aid to obtain the regenerated filter aid.

[0028] Preferably, the regeneration method of the filter aid is as follows: the obtained straw ash and the solid phase of the filter aid are placed in a muffle furnace for calcination to obtain the regenerated filter aid.

[0029] Preferably, the calcination temperature of the solid straw ash and filter aid is 480–550°C, and the calcination time is 2–3 hours.

[0030] It is worth mentioning that, since the ash from straw is amorphous silica ash, it is loose and porous and can be directly mixed and reused as a recycled filter aid, with little impact on the performance of the filter aid.

[0031] It is worth mentioning that straw cellulose enzymatic hydrolysate is a suspension containing sludge-like sticky fine particles, and conventional filtration methods are inefficient. This invention proposes adding a certain amount of modified filter aid to the conventional filtration or centrifugation process of straw cellulose enzymatic hydrolysate. Because the added modified filter aid can form rigid particles with porous cake layers, the viscosity of the filter cake decreases, resulting in good permeability and low fluid resistance, which can greatly accelerate filtration efficiency and throughput. At the same time, the lignin in the obtained filter residue can be recovered using the alkali dissolution method, and the remaining straw ash can be recycled by mixing it with the filter aid after regeneration. It can be seen that this invention provides a low-cost continuous processing technology that can accelerate the production efficiency and scale of straw biomass, thereby better serving the industrial utilization of straw biomass.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1. The modified filter aid used in this invention has a large specific surface area, which can adsorb colloidal substances in enzymatic hydrolysates such as lignin and polysaccharides, and form a filter cake with a high porosity. It is also well-suited for acidic environments under enzymatic hydrolysis or strong acid cellulose hydrolysis.

[0034] 2. This invention uses an amino-type silane coupling agent to modify the filter aid, which effectively avoids the filter aid from caking during enzymatic hydrolysate filtration and subsequent alkaline extraction of lignin, thus preventing it from affecting the filtration rate. The main reason is that pretreatment can change the surface properties of the filter aid. In the enzymatic hydrolysate, lignin, polysaccharides and other colloidal substances carry negative charges and repel each other. When the positively charged amino groups on the surface of the filter aid are adsorbed and neutralized, the repulsive force of the colloidal particles disappears and flocculation occurs. This flocculation includes the self-aggregation of colloidal particles and their aggregation on the surface of the filter aid. This aggregate is a soft flocculent with shear reversibility. The loose soft flocculent filter layer is beneficial for filtration, dehydration and the formation of a uniform filter cake.

[0035] 3. The method of adding modified filter aid to the enzymatic hydrolysate in this invention is simple and easy to implement, which accelerates the filtration rate of the enzymatic hydrolysate, reduces the water content of the filter cake, thereby increasing the solid-liquid separation efficiency and enabling the solid-liquid separation operation to be carried out continuously. At the same time, it can also easily extract lignin from the filter cake. Furthermore, the filter aid of this invention is easy to recover and can be recycled, making it suitable for the biomass industrial application of straw. Attached Figure Description

[0036] Figure 1 The process flow diagram of the present invention, which uses a modified filter aid to promote the enzymatic hydrolysis of straw cellulose and the extraction of lignin, is shown. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0038] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods, and the materials and reagents used are all publicly available in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0039] In the following examples and comparative examples, the filters used can be disc filters, belt filters, or other filtration equipment. For example, the FT-1-400 disc filter from Chongqing Jiangbei Machinery Co., Ltd., with a filtration area of ​​1m², is used. 2 The power is 5.5KW, the rotation speed is 260r / min, the operating pressure is 0.1MPa, and the water washing volume is the same as the enzymatic hydrolysate volume.

[0040] In the following examples and comparative examples, the source of straw raw materials is not limited to common wheat, corn, and sugarcane straw, but can be straw from various crops.

[0041] In the following examples and comparative examples, the straw cellulose enzymatic hydrolysate was obtained from the mixture obtained by the straw pretreatment and enzymatic hydrolysis methods provided in the patent application (application number CN103031340A or application number CN103031339A).

[0042] Example 1

[0043] 10 kg of washed natural diatomaceous earth was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 10 g of 3-aminopropyltrimethoxysilane was added, and the pH of the reaction system was 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. The pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0044] Example 2

[0045] 10 kg of washed natural diatomaceous earth was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 50 g of 3-aminopropyltrimethoxysilane was added, and the pH of the reaction system was 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 5. The pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0046] Example 3

[0047] 10 kg of washed natural diatomaceous earth was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 100 g of 3-aminopropyltrimethoxysilane was added, and the reaction system was kept at pH 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 5. The reaction system was kept at pH 12 and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0048] Example 4

[0049] 10 kg of washed natural diatomaceous earth was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 50 g of 3-aminopropyltriethoxysilane was added, and the pH of the reaction system was 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 5. The pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0050] Example 5

[0051] 10 kg of washed natural diatomaceous earth was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 10 between the natural diatomaceous earth and the alkaline solution. 50 g of N,N-diethyl-3-(trimethoxysilyl)propylamine was added. The pH of the reaction system was 12, and the reaction was carried out at room temperature for 2 hours. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume and filtered using a disc filter. The filter residue was washed with water, and the filtrate was the sugar solution for fermentation. The filter residue was added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 10 between the filter residue and the alkaline solution. The pH of the reaction system was 13, and the reaction was carried out at 40°C for 2 hours. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0052] Example 6

[0053] 10 kg of washed natural diatomaceous earth was added to KOH alkaline solution, with a solid-liquid ratio of 1 / 10. 50 g of N,N-diethyl-3-(triethoxysilyl)propylamine was added. The pH of the reaction system was 12, and the reaction was carried out at room temperature for 2 hours. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume and filtered using a disc filter. The filter residue was washed with water, and the filtrate was the sugar solution for fermentation. The filter residue was then added to KOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 10. The pH of the reaction system was 13, and the reaction was carried out at 40°C for 2 hours. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0054] Example 7

[0055] 10 kg of washed natural diatomaceous earth was added to KOH alkaline solution, with a solid-liquid ratio of 1 / 20 between the natural diatomaceous earth and the alkaline solution. 50 g of N1-(3-(trimethoxysilyl)propyl)ethane-1,2-diamine was added. The pH of the reaction system was 14, and the reaction was carried out at room temperature for 2 hours. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume and filtered using a disc filter. The filter residue was washed with water, and the filtrate was the sugar solution for fermentation. The filter residue was added to KOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 20 between the filter residue and the alkaline solution. The pH of the reaction system was 14, and the reaction was carried out at 60°C for 4 hours. The solution was filtered again, and the filtrate was the alkaline lignin solution. The solid phase after filtration was recovered for later use.

[0056] Example 8

[0057] 10 kg of washed natural diatomaceous earth was added to KOH alkaline solution, with a solid-liquid ratio of 1 / 20 between the natural diatomaceous earth and the alkaline solution. 50 g of N1-(3-(triethoxysilyl)propyl)ethane-1,2-diamine was added. The pH of the reaction system was 14, and the reaction was carried out at room temperature for 2 hours. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume and filtered using a disc filter. The filter residue was washed with water, and the filtrate was the sugar solution for fermentation. The filter residue was added to KOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 20 between the filter residue and the alkaline solution. The pH of the reaction system was 14, and the reaction was carried out at 60°C for 4 hours. The solution was filtered again, and the filtrate was the alkaline lignin solution. The solid phase after filtration was recovered for later use.

[0058] Example 9

[0059] 10 kg of washed natural bleaching clay was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 50 g of 3-aminopropyltrimethoxysilane was added, and the pH of the reaction system was 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 5. The pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0060] Example 10

[0061] 10 kg of washed natural perlite was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 50 g of 3-aminopropyltrimethoxysilane was added, and the reaction system was kept at pH 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 10 of the hydrolysate volume. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 5. The reaction system was kept at pH 12 and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0062] Example 11

[0063] 10 kg of washed natural diatomaceous earth was added to NaOH alkaline solution, with a solid-liquid ratio of 1 / 5. 50 g of 3-aminopropyltrimethoxysilane was added, and the pH of the reaction system was 10. The reaction was carried out at room temperature for 1 hour. After the reaction, the solid was filtered, washed with water, and dried to obtain a modified filter aid. The modified filter aid was added to cellulose enzymatic hydrolysate at a volume of 1 / 50 of the hydrolysate volume. The mixture was filtered using a disc filter, and the filter residue was washed with water. The filtrate was the sugar solution for fermentation. The filter residue was then added to NaOH alkaline solution and heated to react, with a solid-liquid ratio of 1 / 5. The pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution. The solid phase was recovered for later use.

[0064] Comparative Example 1

[0065] The cellulose hydrolysate was filtered using a disc filter. The filtered residue was washed with water, and the filtrate was the sugar solution for fermentation. The residue was then added to NaOH alkaline solution and heated to react. The solid-liquid ratio of the residue to the alkaline solution was 1 / 5, the pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The solution was then filtered again, and the filtrate was the alkaline lignin solution.

[0066] Comparative Example 2

[0067] Washed natural diatomaceous earth was added to the cellulose enzymatic hydrolysate at a volume of 1 / 10. The mixture was then filtered using a disc filter. The filtered residue was washed with water, and the filtrate was the sugar solution used for fermentation. The residue was then added to NaOH alkaline solution and heated to react. The solid-liquid ratio of the residue to the alkaline solution was 1 / 5, the pH of the reaction system was 12, and the reaction was carried out at 20°C for 1 hour. The mixture was then filtered again, and the filtrate was the alkaline lignin solution.

[0068] Table 1 shows the filtration performance test data for Examples 1-11 and Comparative Examples 1-2. All examples and comparative examples used the same filtration device, with the same washing water volume and cellulose hydrolysate volume. Filtration time is the time required for the first filtration of the straw hydrolysate. The filtrate sugar yield is calculated as the total content of glucose and xylose, i.e., the percentage of sugar in the filtrate after washing relative to the content in the straw hydrolysate. The filter cake moisture content is the percentage of water in the filter cake relative to its total mass during the first filtration of the hydrolysate. The alkaline lignin recovery rate is the percentage of lignin from the straw hydrolysate that enters the alkaline solution.

[0069] Table 1

[0070]

[0071] As shown in Table 1, after adding modified filter aids in Examples 1 to 11, even when the amount of modified filter aids added was small (Example 11), the filtration time of the filtrate was significantly shortened, and the sugar yield and lignin yield of the filtrate were significantly increased. At the same time, the moisture content of the filter cake was reduced and the solid content was increased. This can save water consumption and electricity consumption during filtration and drying, and has significant process economy.

[0072] As shown in Comparative Example 1, without the addition of any filter aid, the filtration time is long and the moisture content of the filter cake is too high, resulting in low sugar and lignin yields.

[0073] As shown in Comparative Example 2, while using natural diatomaceous earth directly helps to shorten filtration time and increase the yield of sugar solution and lignin, the effect is significantly less than that of using modified natural diatomaceous earth.

[0074] Furthermore, the solid phases recovered from filtration in Examples 2, 9, and 10 were calcined in a muffle furnace at a temperature of 550°C for 2 hours. The resulting powder was considered a natural filter aid. Following the methods of Examples 2, 9, and 10, silane reagent was added again for modification and reuse. The filtration time of the enzymatic hydrolysate and the moisture content of the filtered cake were tested to evaluate the recycling performance of the reused filter aid. Specific data are shown in Table 2 below.

[0075] Table 2

[0076]

[0077] As shown in Table 2, the recovered filter aid can be reused after calcination and re-modification, which can promote the filtration of enzymatic hydrolysate. Among them, the filter aid of Example 2 has little difference in effect when reused, while the filter aid of Examples 9 and 10 has increased filtration time when reused, and the moisture content of filter cake does not change much.

[0078] The modified filter aid provided by this invention has a good effect on promoting filtration of high-viscosity mixtures, and has the advantages of low energy consumption and high yield.

[0079] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for filtering treatment of a straw cellulose enzymatic hydrolysate, characterized by, The method comprises the following steps: Step one, adding modified filter aid to the straw cellulose enzymatic hydrolysate, performing solid-liquid separation on the mixed solution, washing the filter residue, and collecting the filtrate; Step two, adding the filter residue to alkali liquor B and heating for reaction, and performing filtration again to obtain the solid phase of straw ash and filter aid and the liquid phase containing lignin; The modified filter aid is prepared from filter aid, alkali liquor A, and silane coupling agent; The filter aid is selected from natural silicon dioxide powder.

2. The filtration treatment method of the straw cellulose enzymatic hydrolysate according to claim 1, characterized in that: The natural silicon dioxide powder is selected from at least one of natural diatomite, perlite, and white clay; The particle size of the natural silicon dioxide powder is 50-300 mesh.

3. The method of claim 1, wherein the method is characterized by, The alkali liquor A is selected from an aqueous solution of inorganic strong base.

4. The filtration treatment method of a straw cellulose enzymolysis liquid according to claim 3, characterized in that, The alkali liquor A is selected from an aqueous solution of at least one alkali selected from sodium hydroxide and potassium hydroxide.

5. The method of claim 1, wherein the method is characterized by, The silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N,N-diethyl-3-(trimethoxysilyl)propylamine, N,N-diethyl-3-(triethoxysilyl)propylamine, N1-(3-(trimethoxysilyl)propyl)ethane-1,2-diamine, and N1-(3-(triethoxysilyl)propyl)ethane-1,2-diamine.

6. The method according to any one of claims 1 to 5, wherein the method is characterized by, The preparation method of the modified filter aid comprises the following steps: washing the filter aid with water, adjusting the pH by adding alkali liquor A, and performing solid-liquid separation after adding the silane coupling agent and reacting, and then drying the solid phase to obtain the modified filter aid.

7. The filtration treatment method of the straw cellulose enzymatic hydrolysate according to claim 6, characterized in that: The mass ratio of the filter aid to the added alkali liquor A is 1 / 5-1 / 20; and / or The pH is adjusted to 10-14.

8. The filtration treatment method of the straw cellulose enzymatic hydrolysate according to claim 6, characterized in that: The mass of the added silane coupling agent is 0.1-1% of the mass of the filter aid; and / or The reaction time is 1-2 h, and the reaction temperature is room temperature.

9. The filtration treatment method of a straw cellulose enzymolysis liquid according to claim 8, characterized in that, The mass of the added silane coupling agent is 0.5-1% of the mass of the filter aid.

10. The filtration treatment method of the straw cellulose enzymatic hydrolysate according to claim 1, characterized in that: In the step one, the added amount of the modified filter aid is 1 / 10-1 / 50 of the volume of the liquid; and / or In the step two, the solid-liquid ratio of the filter residue to the alkali liquor B is 1 / 5-1 / 20; and / or The alkali liquor B is an aqueous solution of sodium hydroxide or potassium hydroxide; and / or The pH of the reaction system is 12-14; and / or The heating reaction temperature is 20-60℃; and / or The heating reaction time is 1-4 h.

11. The method of claim 1, wherein the method is characterized by, The method further comprises step three: calcining the solid phase of the straw ash and filter aid to obtain regenerated filter aid.

12. The method of claim 11, wherein the filtration treatment of the straw cellulose enzymolysis liquid is characterized by, The calcination temperature of the solid phase of the straw ash and filter aid is 480-550℃; and / or the calcination time of the solid phase of the straw ash and filter aid is 2-3 h.

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