CN107558284A - Method for extracting lignin and co-producing phosphorus-potassium compound fertilizer by using cellulosic ethanol fermentation residues as raw materials - Google Patents

Abstract

The invention discloses a method for extracting lignin from cellulosic ethanol fermentation residues and co-producing phosphorus and potassium compound fertilizers, comprising the following steps: (1) adding an alkaline aqueous solution containing potassium to the fermentation residues to extract lignin, Solid-liquid separation to obtain a solid residue and an alkali extract; (2) adding a decomposing agent to the obtained solid residue for decomposing treatment; (3) adjusting the pH of the alkali extract to 2-6 with an acidic aqueous solution containing phosphorus , solid-liquid separation, and the solid phase is washed and dried to obtain lignin; (4) drying the filtrate to obtain a phosphorus-potassium compound fertilizer. The invention controls the fertilizer efficiency of the slow-release phosphorus-potassium compound fertilizer by adjusting the pH of the alkali extraction solution through a gradient, thereby meeting the requirements of different crops for the phosphorus-potassium compound fertilizer.

Description

A composite method for extracting lignin and co-producing phosphorus and potassium with cellulosic ethanol fermentation residue as raw material fat method

technical field

The invention belongs to the field of biological energy and biochemical industry, and specifically relates to a method for extracting lignin and co-producing phosphorus and potassium compound fertilizer by using cellulosic ethanol fermentation residue as a raw material.

Background technique

In recent years, with the gradual depletion of fossil resources such as petroleum and the increasingly prominent problems of environmental pollution, the concept of green and low-carbon development has been deeply rooted in the hearts of the people. The refining technology using all components of biomass has become a research and development field that has attracted much attention in the world. , in which fuel ethanol, as a renewable biomass energy, is gradually permeating people's daily life.

In 2015, the global fuel ethanol production reached 98.3 billion liters, accounting for 75% of the total bio-liquid fuel (including ethanol, biodiesel and hydrogenated vegetable oil) production (about 130.7 billion liters). A recognized gasoline alternative fuel. So far, fuel ethanol is mainly produced through fermentation from food crops, sugar crops and non-grain starches. In order to save food, the production of cellulosic ethanol from lignocellulosic biomass will become a development trend in the future.

At present, cellulosic ethanol is still in the stage of industrial experimentation, and there are many sets of demonstration devices at home and abroad. However, its cost competitiveness with grain ethanol has been a limiting factor for the commercialization of cellulosic ethanol. Lignin, as a renewable and biodegradable natural organic polymer compound second only to cellulose in the total amount in nature, is the only non-petroleum resource that can provide a large amount of renewable aromatic compounds, and is used to prepare high value-added Chemicals are key to improving the efficiency of biomass resource utilization. However, in practical applications, only a small portion of lignin is used for other commercial purposes, and most of it is incinerated to recover part of the heat energy. Therefore, if this part of lignin can be effectively used, it can not only reduce environmental pollution, but also improve the economic benefits of traditional biorefinery to a certain extent.

The macronutrient elements nitrogen, phosphorus, and potassium in the soil usually cannot meet the needs of crop growth, and fertilizers containing nitrogen, phosphorus, and potassium need to be supplemented. However, because nitrogen is easily lost through volatilization, leaching, and denitrification; phosphorus fertilizers are easily fixed by A1 ³⁺ , Fe ³⁺ , Ca ²⁺ , and Mg ²⁺ in the soil, forming stable precipitates or combining with iron and aluminum oxides. The formation of closed-stored phosphorus gradually loses its effectiveness, resulting in a very low utilization rate of chemical fertilizers in the current season. Therefore, in order to reduce fertilizer loss, prevent environmental pollution caused by fertilization, increase crop production, and improve fertilizer utilization rate Fertilizer development and application technology research in the development direction of "slow effect, compound and specialization" has become a hot research topic to protect the ecological environment and promote the sustainable development of agricultural economy. Lignin has a large specific surface area and is easy to degrade. It can generate humic acid through microbial degradation in soil, improve soil physical and chemical properties, improve soil permeability, and prevent compaction. Lignin is used as a fertilizer carrier to absorb and encapsulate fertilizers. It can achieve the purpose of fertilizer slow release. In a word, its development and utilization is not only the comprehensive utilization of lignin resources in the cellulosic ethanol fermentation residue, but also solves the loss and pollution of chemical fertilizers, and can provide a new product for reducing the cost of agricultural production.

CN200910014038.3 discloses a method for co-producing cellulose, lignin and compound fertilizer with cottonseed hulls as raw materials. This invention has changed the drawbacks of the domestic prior art in terms of water resources waste and environmental pollution, but its lignin extraction rate is low, and the lignin stripping agent contains potassium permanganate, which greatly damages the natural structure of lignin, and the overall process Complicated and expensive.

Contents of the invention

Purpose of the invention: The present invention provides a method for extracting lignin from cellulosic ethanol fermentation residues and co-producing phosphorus and potassium compound fertilizers, which solves the acid or high-salt wastewater generated in the traditional lignin production process, and is an economical method. Energy-saving and environment-friendly lignin separation and extraction method.

Technical solution: A method of extracting lignin from cellulosic ethanol fermentation residues and co-producing phosphorus and potassium compound fertilizer according to the present invention comprises the following steps:

(1) adding an alkaline aqueous solution containing potassium to the cellulosic ethanol fermentation residue for extraction, and solid-liquid separation to obtain a solid residue and an alkali extract;

(2) adding a decomposing agent to the solid residue obtained in step (1) for decomposing treatment;

(3) adjusting the pH of the alkali extract obtained in step (1) to 2-6 with an acidic aqueous solution containing phosphorus, separating the solid and liquid to obtain a solid phase and a filtrate, and washing and drying the solid phase to obtain lignin;

(4) drying the filtrate obtained in step (3) to obtain phosphorus and potassium compound fertilizer.

The cellulosic ethanol fermentation residue in step (1) includes corn stalk, wheat straw or rice straw fermentation residue, and the cellulosic ethanol fermentation residue is composed of solid matter and water, and the water content is 45-55wt.%. The solid refers to the absolute dry cellulosic ethanol fermentation residue. Cellulose ethanol fermentation residue refers to the solid residue obtained from the solid-liquid separation of the bottom mixture after steam explosion, enzymatic saccharification, slag fermentation, and crude tower rectification of corn stalks, wheat straw or rice straw, and the obtained cellulosic ethanol fermentation residue is immediately subjected to alkali extraction The alkaline aqueous solution containing potassium element includes KOH, K ₂ CO ₃ , KHCO ₃ or K ₂ HPO ₄ aqueous solution; the water in the cellulosic ethanol fermentation residue is mixed with the alkaline aqueous solution containing potassium element to obtain an alkali A mixed solution with a concentration of 1-10wt.%; the solid-liquid ratio of the solid to the mixed solution is 1kg:4-25L; the extraction temperature is 25-130°C, and the extraction time is 0.5-5h.

The decomposing agent described in the step (2) is HM straw decomposing agent, microbial decomposing agent or enzyme bacteria fast decomposing agent, the mass ratio of the decomposing agent to the solid residue is 0.01～1g:1kg, and the decomposing temperature is room temperature, The decomposing time is 7-45 days.

The acidic aqueous solution containing phosphorus in step (3) is phosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphoric anhydride, polyphosphoric acid or acid salt solution of phosphoric acid, and the concentration of the acidic aqueous solution is 75-95wt.%.

When adjusting the pH of the alkali extract in step (3) to be 2≤pH≤3, the fertilizer effect of the phosphorus-potassium compound fertilizer that step (4) makes is greater than or equal to 2 weeks and less than or equal to 6 weeks; when adjusting in step (3) The pH of the alkali extract is 3＜pH≤4, and the fertilizer effect of the phosphorus-potassium compound fertilizer that step (4) makes is greater than 6 weeks and is less than or equal to 14 weeks; When adjusting the pH of the alkali extract in the step (3), it is 4 <pH≤5, the fertilizer effect of the phosphorus-potassium compound fertilizer that step (4) makes is greater than 14 weeks and is less than or equal to 23 weeks; When adjusting the pH of alkali extract in step (3) to be 5＜pH≤6, step (4 ) The fertilizer effect of the phosphorus-potassium compound fertilizer obtained is greater than or equal to 5 weeks and less than 23 weeks.

The equipment used for solid-liquid separation in steps (1) and (3) is a pressure screen, a screw press, a double-cone decanter centrifuge, a disc centrifuge or a plate and frame filter press. The equipment used for drying described in steps (3) and (4) is an industrial dryer, a spray dryer or a microwave dryer.

The alkali extraction step and the step of adjusting the pH of the alkali extraction solution in the present invention all need to be stirred conventionally so that the materials are fully mixed.

Beneficial effects: the present invention uses cellulosic ethanol fermentation residues as raw materials to extract lignin and co-produce phosphorus and potassium compound fertilizers, realizing the utilization of all components of biomass; the present invention extracts lignin by using potassium-containing alkaline aqueous solution, and utilizes Phosphorus-containing acidic aqueous solution adjusts the pH of the alkaline extraction solution to 2-6, which not only ensures the extraction amount of lignin, but also solves the problem of acid or high-salt wastewater generated in traditional lignin extraction methods, and co-produces High value-added slow-release phosphorus and potassium compound fertilizer. Because the compound fertilizer contains a certain amount of lignin, the utilization rate and sustainable cycle of the phosphorus-potassium compound fertilizer are improved; when the pH of the alkali extract is adjusted to 2≤pH≤3, the fertilizer efficiency of the obtained phosphorus-potassium compound fertilizer is Greater than or equal to 2 weeks and less than or equal to 6 weeks; when the pH of the alkali extract is adjusted to 3<pH≤4, the fertilizer efficiency of the phosphorus and potassium compound fertilizer is greater than 6 weeks and less than or equal to 14 weeks; when the pH of the alkali extract is adjusted 4<pH≤5, the fertilizer effect of the obtained phosphorus-potassium compound fertilizer is greater than 14 weeks and less than or equal to 23 weeks; when the pH of the alkali extract is adjusted to be 5<pH≤6, the fertilizer effect of the obtained phosphorus-potassium compound fertilizer is Greater than or equal to 5 weeks and less than 23 weeks. The present invention makes full use of the residual heat after the rectification of the cellulosic ethanol crude tower to participate in the extraction, which reduces the energy consumption of the reaction and improves the economical efficiency of the reaction; the present invention uses the alkali method to extract lignin, which is higher than the organic solvent or ionic liquid extraction method. The extraction rate of lignin is improved, and the production cost is greatly reduced.

Description of drawings

Fig. 1 is the two-dimensional NMR figure of alkali extraction lignin;

Figure 2 is the relationship between the pH of the alkali extract and the content of potassium dihydrogen phosphate, lignin content and slow-release period in the phosphorus-potassium compound fertilizer.

detailed description

The cellulosic ethanol fermentation residue used in the embodiment of the present invention refers to the solid obtained from the solid-liquid separation of the still bottom mixture after steam explosion of corn stalks, enzymatic saccharification, fermentation with slag and rectification in the crude tower, with a solid content of 52.3 wt.%. The lignin content in the dry material is 62.35wt.%, the cellulose content is 9.60wt.%, the silicate ash content is 11.53wt.%, the yeast content is 12.71wt.%, and other soluble impurities are 3.56wt.%. %, the residual temperature of the fermentation residue is 50-80°C, and the obtained cellulosic ethanol fermentation residue is immediately subjected to alkali extraction. In the present invention, wt.% is mass fraction.

Example 1

Get 1kg of corn stalk fiber ethanol fermentation residue and put it into an 8L reaction tank, and add 2.16wt.% KOH aqueous solution 5.799L thereinto to adjust the final alkali concentration of the reaction solution (referring to the water and KOH in the corn stalk fiber ethanol fermentation residue The alkali concentration in the mixed solution obtained by mixing the aqueous solution, the same below) is 2wt.%, and the final solid-liquid ratio (referring to the solid-liquid ratio of the absolute dry substance in the corn stalk fiber ethanol fermentation residue and the mixed solution, the same below) is 1kg: 12L, and then extract lignin by alkaline method at 70°C for 3h. After the reaction, the screw press was used to separate the solid and liquid, and the mass ratio of HM straw decomposing and solid phase residue was 0.1g:1kg, and the composting treatment was carried out for 15 days, so as to realize the reuse of biomass in the field, and the filtrate was lignin solution.

Slowly add 85wt.% industrial phosphoric acid to the lignin solution to adjust its pH to 4, during which the stirring speed is set to 500rpm. Afterwards, the lignin solution is injected into the plate and frame filter device, and solid-liquid separation is performed again. The solid phase is washed and dried to obtain lignin solid powder; the liquid phase is spray-dried, and the final product can be used as a high-efficiency slow-release phosphorus and potassium compound fertilizer.

After treatment, a total of 317.4g of crude lignin was obtained, with a water content of 9.7wt.%, a lignin purity of 84.5wt.%, a residual sugar content of 2.3wt.%, and a silicate ash content of 4.9wt.%. The element extraction rate is 74.3%; Obtain spray dried thing 275.4g altogether, its residual sugar content is 4.7wt.%, silicate ash is divided into 8.6wt.%, lignin content is 14.8wt.%, and the content of potassium dihydrogen phosphate is 70.3 wt.%.

Wherein, the moisture content of lignin is the ratio of the mass of the crude lignin product obtained after being dried to a constant weight to the original total mass, and the lignin purity is the percentage of the lignin mass in the crude lignin product obtained to the total mass of the product, The lignin extraction rate is the percentage of the lignin quality in the obtained lignin crude product and the theoretical total lignin content contained in the raw material, and the potassium dihydrogen phosphate content is the mass of the obtained spray-dried potassium dihydrogen phosphate and the total mass of the spray-dried product The ratio of , the same below.

Example 2

Take 1kg of corn stalk fiber ethanol fermentation residue and put it into an 8L reaction tank, and add 4.753L of 3.30wt.% KOH aqueous solution to it to adjust the final alkali concentration of the reaction solution to 3wt.%, and the final solid-liquid ratio to 1kg:10L , and then lignin was extracted by alkaline method at 80°C for 2.5h. After the reaction, the screw press was used to separate the solid and liquid, and the mass ratio of HM straw decomposing and solid phase residue was 0.1g:1kg, and the composting treatment was carried out for 15 days, so as to realize the reuse of biomass in the field, and the filtrate was lignin solution.

Slowly add 85wt.% industrial phosphoric acid to the lignin solution to adjust its pH to 4, during which the stirring speed is set to 500rpm. The mixture is then injected into a plate and frame filter device for solid-liquid separation again. The solid phase is washed and dried to obtain lignin solid powder; the liquid phase is spray-dried, and the final product can be used as a high-efficiency slow-release phosphorus and potassium compound fertilizer.

After treatment, a total of 331.4g of crude lignin was obtained, with a water content of 7.2wt.%, a lignin purity of 83.9wt.%, a residual sugar content of 2.6wt.%, and a silicate ash content of 5.7wt.%. The prime extraction rate is 79.1%; Obtain 368.5g of spray-dried thing altogether, its residual sugar content is 4.3wt.%, silicate ash is divided into 8.1wt.%, lignin content is 11.2wt.%, and the content of potassium dihydrogen phosphate is 74.7 wt.%.

Example 3

Take 1kg of corn stalk fiber ethanol fermentation residue and put it into an 8L reaction tank, and add 4.230L of 4.45wt.% KOH aqueous solution to it to adjust the final alkali concentration of the reaction solution to 4wt.%, and the final solid-liquid ratio to 1kg:9L , and then lignin was extracted by alkaline method at 90° C. for 1 h. After the reaction, use a screw press for solid-liquid separation, and mix and compost the HM straw for 15 days at a mass ratio of 0.1 g: 1 kg to solid phase residue, so as to realize the reuse of biomass in the field. The liquid is lignin solution.

Slowly add 85wt.% industrial phosphoric acid to the lignin solution to adjust its pH to 4, during which the stirring speed is set to 500rpm. The mixture is then injected into a plate and frame filter device for solid-liquid separation again. The solid phase is washed and dried to obtain lignin solid powder; the liquid phase is spray-dried, and the final product can be used as a high-efficiency slow-release phosphorus and potassium compound fertilizer.

After treatment, a total of 340.2g of lignin crude product was obtained, with a water content of 4.8wt.%, a lignin purity of 82.7wt.%, a residual sugar content of 2.8wt.%, and a silicate ash content of 7.3wt.%. Extraction rate of element is 82.1%; Obtain 432.9g of spray-dried thing altogether, its residual sugar content is 3.8wt.%, silicate ash is divided into 6.7wt.%, lignin content is 9.1wt.%, and the content of potassium dihydrogen phosphate is 75.2 wt.%. In this embodiment, the nutrient utilization rate of the slow-release compound fertilizer is 74%, and the fertilizer effect can last for 14 weeks.

Example 4

Take 1kg of corn stalk fiber ethanol fermentation residue and put it into an 8L reaction tank, and add 3.707L of 5.64wt.% KOH aqueous solution to it to adjust the final alkali concentration of the reaction solution to 5wt.%, and the final solid-liquid ratio to 1kg:8L , and then lignin was extracted by alkaline method at 110°C for 1.5h. After the reaction, use a screw press for solid-liquid separation, and mix and compost the HM straw for 15 days at a mass ratio of 0.1 g: 1 kg to solid phase residue, so as to realize the reuse of biomass in the field. The liquid is lignin solution.

Slowly add 85wt.% industrial phosphoric acid to the lignin solution to adjust its pH to 4, during which the stirring speed is set to 500rpm. The mixture is then injected into a plate and frame filter device for solid-liquid separation again. The solid phase is washed and dried to obtain lignin solid powder; the liquid phase is spray-dried, and the final product can be used as a high-efficiency slow-release phosphorus and potassium compound fertilizer.

After treatment, a total of 325.7g of lignin crude product was obtained, with a water content of 4.3wt.%, a lignin purity of 81.9wt.%, a residual sugar content of 2.4wt.%, and a silicate ash content of 4.9wt.%. The element extraction rate is 78.3%; Obtain spray-dried thing 492.5g altogether, its residual sugar content is 2.4wt.%, silicate ash is divided into 5.1wt.%, lignin content is 6.7wt.%, and the content of potassium dihydrogen phosphate is 83.8 wt.%.

Example 5

Take 1kg of corn stalk fiber ethanol fermentation residue and put it into an 8L reaction tank, and add 2.661L of 7.08wt.% KOH aqueous solution to it to adjust the final alkali concentration of the reaction solution to 6wt.%, and the final solid-liquid ratio to 1kg:6L , and then extract lignin by alkaline method at 50°C for 2h. After the reaction, use a screw press for solid-liquid separation, and mix and compost the HM straw for 15 days at a mass ratio of 0.1 g: 1 kg to solid phase residue, so as to realize the reuse of biomass in the field. The liquid is lignin solution.

Slowly add 85wt.% industrial phosphoric acid to the lignin solution to adjust its pH to 4, during which the stirring speed is set to 500rpm. The mixture is then injected into a plate and frame filter device for solid-liquid separation again. The solid phase is washed and dried to obtain lignin solid powder; the liquid phase is spray-dried, and the final product can be used as a high-efficiency slow-release phosphorus and potassium compound fertilizer.

After treatment, a total of 309.5g of lignin crude product was obtained, with a water content of 3.7wt.%, a lignin purity of 80.2wt.%, a residual sugar content of 4.3wt.%, and a silicate ash content of 8.6wt.%. The element extraction rate is 73.3%; Obtain spray dried thing 426.9g altogether, its residual sugar content is 3.5wt.%, silicate ash is divided into 6.3wt.%, lignin content is 4.2wt.%, and the content of potassium dihydrogen phosphate is 84.6 wt.%.

Example 6

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 2. A total of 345.7g of lignin crude product was obtained, the water content was 4.7wt.%, the lignin purity was 91.2wt.%, the residual sugar content was 0.9wt.%, the silicate ash was 1.7wt.%, and the lignin extraction rate was Be 92.1%; Obtain altogether 467.5g of spray-dried matter, its residual sugar content is 3.7wt.%, silicate ash is 7.4wt.%, lignin content is 3.2wt.%, and the content of potassium dihydrogen phosphate is 54.3wt. %. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 38%, and the fertilizer effect can last for 2 weeks.

Example 7

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 2.5. A total of 343.9g of lignin crude product was obtained, the water content was 5.1wt.%, the lignin purity was 89.4wt.%, the residual sugar content was 2.5wt.%, the silicate ash was 3.8wt.%, and the lignin extraction rate was Be 89.5%; Obtain altogether 451.7g of spray-dried thing, its residual sugar content is 3.4wt.%, silicate ash is 6.9wt.%, lignin content is 4.3wt.%, and the content of potassium dihydrogen phosphate is 65.4wt. %. In this embodiment, the nutrient utilization rate of the slow-release compound fertilizer is 43%, and the fertilizer effect can last for 4 weeks.

Example 8

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to be 3. A total of 342.1g of lignin crude product was obtained, the water content was 4.5wt.%, the lignin purity was 87.2wt.%, the residual sugar content was 2.1wt.%, the silicate ash was 4.7wt.%, and the lignin extraction rate was Be 87.4%; Obtain altogether 435.7g of spray-dried thing, its residual sugar content is 4.3wt.%, silicate ash is 6.5wt.%, lignin content is 5.5wt.%, and the content of potassium dihydrogen phosphate is 72.5wt. %. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 51%, and the fertilizer effect can last for 6 weeks.

Example 9

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 3.5. A total of 341.3g of lignin crude product was obtained, the water content was 4.9wt.%, the lignin purity was 85.1wt.%, the residual sugar content was 2.5wt.%, the silicate ash was 5.3wt.%, and the lignin extraction rate was 84.7%; Obtain 439.4g of spray-dried matter altogether, its residual sugar content is 4.5wt.%, silicate ash is 6.1wt.%, lignin content is 7.9wt.%, and the content of potassium dihydrogen phosphate is 76.3wt. %. The nutrient utilization rate of the slow-release phosphorus and potassium compound fertilizer in this embodiment is 62%, and the fertilizer effect can last for 10 weeks.

Example 10

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 4.5. A total of 340.7g of lignin crude product was obtained, the water content was 4.6wt.%, the lignin purity was 81.5wt.%, the residual sugar content was 5.4wt.%, the silicate ash was 8.6wt.%, and the lignin extraction rate was 81.2%; Obtain 426.9g of spray-dried matter altogether, its residual sugar content is 4.7wt.%, silicate ash is 7.2wt.%, lignin content is 14.3wt.%, and the content of potassium dihydrogen phosphate is 74.6wt. %. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 80%, and the fertilizer effect can last for 20 weeks.

Example 11

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 5. A total of 341.8g of lignin crude product was obtained, the water content was 5.0wt.%, the lignin purity was 80.7wt.%, the residual sugar content was 4.6wt.%, the silicate ash was 7.3wt.%, and the lignin extraction rate was It is 80.4%; Obtain 432.9g of spray-dried thing altogether, its residual sugar content is 3.8wt.%, silicate ash is 6.9wt.%, lignin content is 19.4wt.%, and the content of potassium dihydrogen phosphate is 68.3wt. %. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 85%, and the fertilizer effect can last for 23 weeks.

Example 12

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 5.5. A total of 134.8g of lignin crude product was obtained, the water content was 5.2wt.%, the lignin purity was 78.6wt.%, the residual sugar content was 3.4wt.%, the silicate ash was 7.5wt.%, and the lignin extraction rate was It is 30.8%; Obtain 367.3g of spray-dried thing altogether, its residual sugar content is 4.3wt.%, silicate ash is 8.4wt.%, lignin content is 31.2wt.%, and the content of potassium dihydrogen phosphate is 43.7wt. %. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 89%, and the fertilizer effect can last for 8 weeks.

Example 13

The same conditions as in Example 3 were adopted, except that the pH of the lignin solution was adjusted to 6. A total of 79.8g of lignin crude product was obtained, the water content was 5.5wt.%, the lignin purity was 77.6wt.%, the residual sugar content was 5.7wt.%, the silicate ash content was 8.9wt.%, and the lignin extraction rate was It is 17.9%; Obtain 286.7g of spray-dried thing altogether, its residual sugar content is 4.8wt.%, silicate ash is 9.2wt.%, lignin content is 37.8wt.%, and the content of potassium dihydrogen phosphate is 23.5wt. %. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 93%, and the fertilizer effect can last for 5 weeks.

Example 14

Take 1000kg of corn stalk fiber ethanol fermentation residue and put it into an 8m reaction tank, and add ^4230L of 4.45wt.% KOH aqueous solution to it to adjust the final alkali concentration of the reaction solution to 4wt.%, and the final solid-liquid ratio is 1kg:9L , lignin was extracted by alkaline method at 90°C for 1h. After the reaction, the screw press was used to separate the solid and liquid, and the mass ratio of HM straw decomposing and solid phase residue was 0.1g:1kg, and the composting treatment was carried out for 15 days, so as to realize the reuse of biomass in the field, and the filtrate was for the lignin solution.

Slowly add 85wt.% industrial phosphoric acid to the lignin solution to adjust its pH to 5, during which the stirring speed is set to 500rpm. The mixture is then injected into a plate and frame filter device for solid-liquid separation again. The solid phase is washed and dried to obtain lignin solid powder; the liquid phase is spray-dried, and the final product can be used as a high-efficiency slow-release phosphorus and potassium compound fertilizer.

After treatment, a total of 341.9kg of crude lignin products were obtained, with a water content of 4.9wt.%, a lignin purity of 80.3wt.%, a residual sugar content of 3.2wt.%, and a silicate ash content of 5.1wt.%. Extraction rate of element is 80.1%; Obtain 452.7kg of spray-dried thing altogether, its residual sugar content is 3.2wt.%, silicate ash is divided into 5.1wt.%, lignin content is 17.4wt.%, and the content of potassium dihydrogen phosphate is 72.3 wt.%. The nutrient utilization rate of the slow-release compound fertilizer in this embodiment is 82%, and the fertilizer effect can last for 21 weeks.

The cellulosic ethanol fermentation residue is mainly used for combustion and heat supply at present. It needs to be processed in the early stage by block making and drying. High-efficiency utilization will produce serious environmental pollution at the same time. According to the cost calculation of processing 1t of fiber ethanol fermentation residue, the processing fee (including water fee, electricity fee, steam, etc.) is 180 yuan, and the chemical medicine is 2824 yuan. The total investment is 3004 yuan, and the product output is 4477 yuan. At the same time, additional products such as compost can be obtained. And no three wastes are generated. Among them, industrial electricity is 0.79 yuan/kWh, tap water is 2.1 yuan/m ³ , heating steam is 124 yuan/ton; KOH is 8,000 yuan/ton, industrial phosphoric acid is 4,000 yuan/ton, potassium dihydrogen phosphate is 9,500 yuan/ton, crude lignin 4000 yuan/ton.

Example 15

Using the same conditions as in Example 3, the difference is that the final alkali concentration is 1wt.%, the final solid-to-liquid ratio is 1kg:4L, and the lignin is extracted by alkaline method at 130° C. for 5 hours. The mass ratio of HM straw decomposed to solid phase residue was 0.01g:1kg and mixed for composting for 45 days.

Example 16

The same conditions as in Example 3 were used, except that the final alkali concentration was 10wt.% during the alkali extraction, the final solid-to-liquid ratio was 1kg:25L, and the lignin was extracted by alkali method at 25°C for 0.5h. The mass ratio of HM straw decomposed to solid phase residue was 1g:1kg and mixed for 7 days.

Example 17

Using the same conditions as in Example 3, the difference is that the alkaline aqueous solution is a K ₂ CO ₃ aqueous solution, and the acidic aqueous solution is a pyrophosphoric acid aqueous solution.

Example 18

Adopt the same condition with embodiment ₃ , difference is that alkaline aqueous solution is KHCO aqueous solution, and acidic aqueous solution is metaphosphoric acid aqueous solution.

Example 19

Using the same conditions as in Example 3, the difference is that the alkaline aqueous solution is an aqueous solution of K ₂ HPO ₄ , and the acidic aqueous solution is an aqueous solution of phosphoric anhydride.

Example 20

The same conditions as in Example 3 were adopted, except that the cellulosic ethanol fermentation residue used was wheat straw fermentation residue.

Example 21

Using the same conditions as in Example 3, the difference is that the cellulosic ethanol fermentation residue used is rice straw fermentation residue.

Example 22

Adopt the same condition as embodiment 3, the difference is that the decomposing agent used is a microbial putrefaction agent.

Example 23

Adopt the condition identical with embodiment 3, difference is that the decomposing agent that uses is ferment bacterium quick-decomposing agent.

Claims (9)

1. a kind of method that lignin co-production phosphorus potassium complex fertilizer is extracted using fermenting cellulosic ethanol residue as raw material, its feature exist In comprising the following steps：

(1) add the alkaline aqueous solution containing potassium element into fermenting cellulosic ethanol residue to be stripped, separation of solid and liquid obtains solid Residue and alkali extract；

(2) decomposing agent is added in the solid residue obtained to step (1) and carries out decomposed processing；

(3) pH to 2~6 of the alkali extract obtained with the acidic aqueous solution regulating step (1) of phosphorus element-containing, separation of solid and liquid obtains Solid phase and filtrate, solid phase is scrubbed to be drying to obtain lignin；

(4) obtained phosphorus potassium complex fertilizer is dried in the filtrate that step (3) obtains.

2. according to the method for claim 1, it is characterised in that fermenting cellulosic ethanol residue described in step (1) includes jade Rice stalk, straw or rice straw fermented residue, the fermenting cellulosic ethanol residue are made up of solid content and water, and the content of the water is 45~55wt.%.

3. according to the method for claim 1, it is characterised in that the alkaline aqueous solution bag containing potassium element described in step (1) Include KOH, K₂CO₃、KHCO₃Or K₂HPO₄The aqueous solution.

4. according to the method for claim 2, it is characterised in that the water described in step (1) in fermenting cellulosic ethanol residue The mixed liquor that alkali concn is 1~10wt.% is mixed to get with the alkaline aqueous solution containing potassium element.

5. according to the method for claim 4, it is characterised in that the solid-to-liquid ratio of solid content and mixed liquor described in step (1) For 1kg:4~25L.

6. according to the method for claim 1, it is characterised in that extraction temperature described in step (1) is 25~130 DEG C, is taken out It is 0.5~5h to carry the time.

7. according to the method for claim 1, it is characterised in that decomposing agent described in step (2) is HM straw decomposing inoculants, micro- Biological decomposition agent or ferment bacterium quick rotting agent, the mass ratio of the decomposing agent and solid residue is 0.01~1g:1kg, it is described decomposed Temperature is room temperature, and the decomposed time is 7~45 days.

8. according to the method for claim 1, it is characterised in that the acidic aqueous solution bag of phosphorus element-containing described in step (3) Include the acid saline solution of phosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphoric anhydride, polyphosphoric acids or phosphoric acid, the concentration of the acidic aqueous solution For 75~95wt.%.

9. according to the method for claim 1, it is characterised in that in the step (3) pH of regulation alkali extract for 2≤pH≤ 3, the fertilizer efficiency of phosphorus potassium complex fertilizer made from step (4) is to be less than or equal to 6 weeks more than or equal to 2 weeks；When regulation alkali density in step (3) The pH of liquid is 3 ＜ pH≤4, and the fertilizer efficiency of phosphorus potassium complex fertilizer made from step (4) is to be less than or equal to 14 weeks more than 6 weeks；When step (3) The pH of middle regulation alkali extract is 4 ＜ pH≤5, and the fertilizer efficiency of phosphorus potassium complex fertilizer made from step (4) is to be less than or equal to more than 14 weeks 23 weeks；When the pH of regulation alkali extract in step (3) is 5 ＜ pH≤6, the fertilizer efficiency of phosphorus potassium complex fertilizer is big made from step (4) In equal to 5 weeks be less than 23 weeks.