Resource recycling method for kitchen garbage

Abstract

The invention relates to a resource recycling method for kitchen garbage, and belongs to the technical field of garbage resource recycling. According to the method, saccharification fermentation, anaerobic fermentation and aerobic composting treatment are matched for use, so that organic matters in the kitchen garbage can be fully utilized to generate byproducts such as oil, ethanol, biogas and a soil conditioner, the types of resource products are enriched, the economic value of the resource products is improved, and the resource utilization rate of the kitchen garbage is increased. Meanwhile, fermentation and heating are performed in the stage of producing ethanol through saccharification and fermentation, and most residues are decomposed into small molecular substances, so that subsequent reaction is facilitated, and the reaction efficiency of an anaerobic fermentation link is effectively improved. According to the method, the kitchen garbage can be subjected to full-quantitative treatment and residue-free outward transportation treatment, and the biogas generated by anaerobic fermentation can be used as a fuel and used for producing steam or biogas for power generation to be supplied to other process links, so that the energy consumption is reduced, and the overall treatment cost of the kitchen garbage is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of waste resource recycling, and in particular to a method for recycling kitchen waste. Background Art

[0002] Kitchen waste mainly includes physical residues, leftovers, fruit peels, etc. generated by households, schools, canteens, restaurants, etc. It has the characteristics of high water content, high organic matter, high salt content, high oil content and easy to rot. With the advancement of urbanization and the improvement of people's living standards, the amount of kitchen waste generated has increased year by year. If it is not handled in a timely and effective manner, it will produce odors, breed pathogens and microorganisms, and cause environmental pollution problems.

[0003] At present, the existing kitchen waste treatment technologies can be divided into sanitary landfill, incineration, anaerobic digestion, aerobic composting, biological breeding, crushing and direct discharge, etc. Traditional treatment methods still have many problems, such as low resource utilization, narrow outlets for by-products, high risk of homologous pollution, and increased pressure on urban pipe networks, which results in high kitchen waste treatment costs. Summary of the invention

[0004] The present application provides a method for recycling kitchen waste so as to fully realize the recycling of kitchen waste.

[0005] The present application provides a method for recycling kitchen waste, the method comprising:

[0006] sorting and pulping the kitchen waste to obtain kitchen waste slurry;

[0007] Performing three-phase separation on the kitchen waste slurry to obtain a liquid phase, an oil phase and a solid phase;

[0008] Processing the oil phase to obtain biodiesel;

[0009] subjecting the solid phase and part of the liquid phase to saccharification and fermentation to obtain ethanol and saccharification and fermentation residues;

[0010] Anaerobic fermentation of the saccharification and fermentation residue and the remaining liquid phase to obtain biogas, biogas residue and biogas liquid;

[0011] Purifying the biogas slurry to obtain discharge water and activated sludge;

[0012] The biogas residue and activated sludge are subjected to aerobic composting treatment to obtain a soil conditioner.

[0013] As an optional embodiment, the particle size of the solid phase in the kitchen waste slurry is below 8 mm.

[0014] As an optional implementation manner, in the saccharification and fermentation, the mass ratio of the solid phase to the liquid phase is (1-1.5):1.

[0015] As an optional embodiment, the temperature of the saccharification process in the saccharification and fermentation is 55°C to 60°C; and / or

[0016] The saccharification process in the saccharification and fermentation lasts for 1 hour to 5 hours.

[0017] As an optional implementation manner, when the total amount of carbohydrate substances in the saccharification process in the saccharification and fermentation is 1g, the amount of saccharifying enzyme added in the saccharification process in the saccharification and fermentation is 80u-100u.

[0018] As an optional embodiment, the fermentation temperature during the saccharification and fermentation is 28°C to 32°C; and / or

[0019] The fermentation time of the saccharification and fermentation process is 1.5 days to 2 days.

[0020] As an optional embodiment, the inoculation amount of active dry yeast in the fermentation process of the saccharification and fermentation is 8% to 12% of the total mass of sugar content in the solid phase and the liquid phase in the slurry to be fermented.

[0021] As an optional embodiment, the anaerobic fermentation adopts continuous fermentation.

[0022] As an optional embodiment, the temperature of the anaerobic fermentation is 35°C to 40°C; and / or

[0023] The anaerobic fermentation time is 30d to 40d.

[0024] As an optional implementation, the aerobic composting treatment adopts batch fermentation treatment, and a single fermentation cycle is 7d to 10d.

[0025] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0026] The method provided in the embodiment of the present application can make full use of the organic matter in the kitchen waste by using saccharification and fermentation, anaerobic fermentation and aerobic composting treatment to generate by-products such as oil, ethanol, biogas, soil conditioner, etc., enriching the types of resource products, improving the economic value of resource products, and improving the resource utilization rate of kitchen waste. At the same time, the saccharification and fermentation ethanol production stage has been fermented and heated, and most of the residues have been decomposed into small molecules, which is helpful for subsequent reactions and effectively improves the reaction efficiency of the anaerobic fermentation link. This method can fully process kitchen waste without residue transportation, and the biogas produced by anaerobic fermentation can be used as fuel for the production of steam or biogas power generation for use in other process links, saving energy consumption and reducing the overall cost of kitchen waste treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 A schematic diagram of a process for a method provided in an embodiment of the present application;

[0030] Figure 2 A process diagram of the method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0033] Figure 1 A schematic diagram of a method provided in an embodiment of the present application, Figure 2 The process diagram of the method provided in the embodiment of the present application is as follows: Figure 1 and Figure 2 As shown, the embodiment of the present application provides a method for recycling kitchen waste, the method comprising:

[0034] S1. sorting and pulping the kitchen waste to obtain kitchen waste slurry;

[0035] First, the food waste is sorted to remove non-organic materials (such as plastics, metals, etc.). Then, the organic part is crushed and mixed to form food waste slurry. This step helps the uniformity and efficiency of subsequent processing.

[0036] In some embodiments, the particle size of the solid phase in the food waste slurry is below 8 mm.

[0037] The particle size of the solid phase in the kitchen waste slurry is limited to less than 8 mm. The reduction of the solid phase particle size helps to increase the contact area between the solid phase material and the microorganisms and the fermentation liquid, thereby improving the degradation efficiency of the microorganisms on the organic matter. In addition, the smaller particle size can also make the solid phase material more evenly dispersed in the liquid phase, avoiding the problem of uneven fermentation caused by excessively high or low local concentrations. In actual operation, the solid phase material in the kitchen waste can be processed to a particle size range that meets the requirements through physical methods such as crushing and grinding. At the same time, in the sorting and pulping stage, the size of the solid phase particle size can also be controlled by adjusting the process parameters (such as the rotation speed of the crusher, the aperture of the screen, etc.).

[0038] S2. performing three-phase separation on the kitchen waste slurry to obtain a liquid phase, an oil phase and a solid phase;

[0039] The kitchen waste slurry is separated into liquid phase, oil phase and solid phase through three-phase separation technology. The liquid phase mainly contains water and soluble organic matter; the oil phase is the grease component in the kitchen waste; and the solid phase is the remaining solid organic matter.

[0040] S3. processing the oil phase to obtain biodiesel;

[0041] The oil phase can be converted into biodiesel after processing, such as transesterification reaction. Biodiesel is a renewable energy source with the dual advantages of environmental protection and economy.

[0042] S4. saccharifying and fermenting the solid phase and part of the liquid phase to obtain ethanol and saccharification and fermentation residues;

[0043] The solid phase and part of the liquid phase are sent to the saccharification and fermentation system, where the organic matter is converted into ethanol through the action of microorganisms. The saccharification and fermentation process will produce residual solid and liquid substances, which will be used for subsequent anaerobic fermentation. During this process, most of the residues will be broken down into small molecules, such as glucose, which are easily used by subsequent microorganisms. The fermentation and heating process helps to accelerate the reaction and improve the yield and quality of ethanol.

[0044] In some embodiments, in the saccharification and fermentation, the mass ratio of the solid phase to the liquid phase is (1-1.5): 1. The temperature of the saccharification process in the saccharification and fermentation is 55° C. to 60° C.; the time of the saccharification process in the saccharification and fermentation is 1 h to 5 h.

[0045] The mass ratio of the solid phase to the liquid phase is set to (1-1.5):1, which means that the mass of the solid phase is between 1 and 1.5 times in each portion of the liquid phase. The selection of this ratio is intended to balance the microbial demand for nutrition and the decomposition efficiency of solid organic matter during saccharification and fermentation. Too high a solid phase ratio may lead to insufficient dissolved oxygen in the fermentation broth, affecting the activity of the microorganisms; while too low a solid phase ratio may reduce the yield of the fermentation product. Exemplarily, the mass ratio of the solid phase to the liquid phase can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1.

[0046] The temperature of the saccharification process is controlled between 55°C and 60°C. This temperature range is conducive to the activity of saccharifying enzymes (such as α-amylase, β-amylase, etc.), and promotes the decomposition of starch and other polysaccharides. At the same time, this temperature is also suitable for the growth and metabolism of most microorganisms involved in saccharification and fermentation. Exemplarily, the temperature of the saccharification process can be 55°C, 56°C, 57°C, 58°C, 59°C, and 60°C.

[0047] The saccharification process is set to last for 1 hour to 5 hours. The selection of this time range depends on the properties of the solid phase, the activity of the saccharifying enzyme, and the desired degree of saccharification. A shorter saccharification time may not be enough to completely decompose the polysaccharides in the solid phase; while a too long saccharification time may result in a waste of energy and a decrease in microbial activity. Exemplarily, the saccharification process may last for 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours.

[0048] In some embodiments, when the total amount of carbohydrate substances in the saccharification process of the saccharification and fermentation is 1 g, the amount of saccharifying enzyme added in the saccharification process of the saccharification and fermentation is 80 u to 100 u.

[0049] Saccharifying enzymes are a class of enzymes that can hydrolyze polysaccharides into monosaccharides or small molecule sugars. In the saccharification and fermentation process of kitchen waste resource recycling, the main function of saccharifying enzymes is to hydrolyze polysaccharides such as starch and cellulose in the solid phase into monosaccharides such as glucose, providing substrates for the subsequent fermentation process. Therefore, the amount of saccharifying enzyme added directly affects the efficiency of the saccharification process and the quality of the product. The total amount of saccharides in the saccharification process determines the concentration of the substrate. The higher the substrate concentration, the greater the amount of saccharifying enzyme required. However, too high a substrate concentration may lead to incomplete saccharification because the enzyme has less contact with the substrate. In this case, the total amount of saccharides is 1g, which is a relatively low concentration, so the selected saccharifying enzyme addition amount is between 80u and 100u. This parameter setting can ensure the efficiency, stability and environmental protection of the saccharification process and provide sufficient substrate for the subsequent fermentation process. Illustratively, when the total amount of carbohydrate substances in the saccharification process of the saccharification and fermentation is 1 g, the amount of saccharifying enzyme added in the saccharification process of the saccharification and fermentation can be 80u, 850u, 90u, 950u, or 100u.

[0050] In some embodiments, the fermentation temperature of the saccharification and fermentation process is 28°C to 32°C; the fermentation time of the saccharification and fermentation process is 1.5 days to 2 days. The inoculation amount of active dry yeast in the fermentation process of the saccharification and fermentation is 8% to 12% of the total sugar content in the solid phase and the liquid phase in the fermented slurry.

[0051] The temperature of the fermentation process is set to 28°C to 32°C, which is conducive to the growth and reproduction of yeast, as well as the production of alcohol and other fermentation products. Within this temperature range, the metabolic activity of yeast is most active, and it can efficiently use the substrate for fermentation. At the same time, this temperature also avoids the adverse effects of too high or too low temperatures on yeast activity. Exemplarily, the temperature of the fermentation process can be 28°C, 29°C, 30°C, 31°C, or 32°C.

[0052] The fermentation time is set to 1.5d to 2d (days), and the selection of this time range depends on the nature of the substrate, the activity of the yeast, and the desired fermentation product. A shorter fermentation time may not be enough to fully utilize the substrate for fermentation, resulting in a decrease in product yield and quality; while an excessively long fermentation time may lead to an increase in the impurity content in the product and increase production costs. Therefore, a fermentation time of 1.5d to 2d is a relatively reasonable choice. Exemplarily, the fermentation time can be 1.5d, 1.6d, 1.7d, 1.8d, 1.9d, or 2d.

[0053] The inoculation amount of active dry yeast is set to 8% to 12% of the total sugar content in the solid and liquid phases of the fermented slurry. The selection of this inoculation amount is intended to ensure that the yeast can quickly occupy a dominant position and inhibit the growth of other bacteria, thereby ensuring the smooth progress of the fermentation process. At the same time, an appropriate amount of yeast inoculation can also improve fermentation efficiency, shorten fermentation time, and help improve product quality. In actual operation, the selection of inoculation amount also needs to be adjusted according to specific fermentation conditions (such as temperature, pH value, substrate concentration, etc.) and the needs of the target product. Exemplarily, the inoculation amount of active dry yeast can be 8%, 9%, 10%, 11%, and 12% of the total sugar content in the solid and liquid phases of the fermented slurry.

[0054] In this embodiment, the solid phase and the liquid phase are mixed in a certain proportion, saccharifying enzyme and bacterial agent are added, and after a certain period of fermentation, the mixture enters the distillation device to extract ethanol. Among them, the saccharification and fermentation process is a batch fermentation. Before saccharification, the solid phase and the liquid phase after the three-phase separation of the kitchen waste slurry are mixed in a ratio of 1 to 1.5: 1 and continuously stirred, and the temperature is raised to above 105°C and maintained for 30 minutes to kill the miscellaneous bacteria in the kitchen waste slurry. The temperature of the saccharification process is maintained at 55 to 60°C, saccharifying enzyme is added, the saccharification time is 3 to 5 hours, and the amount of saccharifying enzyme added is 80 to 100 (u / g). The temperature of the fermentation process is maintained at 28 to 32°C, active dry yeast is added, the inoculation amount is 8 to 12% of the sugar contained in the slurry, and the fermentation time is 1.5 to 2 days.

[0055] S5. The saccharification and fermentation residue and the remaining liquid phase are subjected to anaerobic fermentation to obtain biogas, biogas residue and biogas liquid;

[0056] The saccharification and fermentation residues and the remaining liquid phase are sent to the anaerobic fermentation system to produce biogas, biogas residue and biogas liquid through the action of microorganisms under anaerobic conditions. Biogas is a renewable energy source that can be used for power generation or as fuel; biogas residue and biogas liquid contain rich nutrients and can be used for subsequent soil conditioning.

[0057] In some embodiments, the anaerobic fermentation is continuous fermentation. The temperature of the anaerobic fermentation is 35° C. to 40° C.; and the time of the anaerobic fermentation is 30 days to 40 days.

[0058] Continuous fermentation is an efficient anaerobic fermentation method that allows materials to flow continuously in the fermentation device, thereby maintaining a stable fermentation environment and product output. Compared with intermittent fermentation, continuous fermentation has higher production efficiency and more stable product quality. In the recycling of kitchen waste resources, the use of continuous fermentation can more effectively process a large amount of kitchen waste and generate more energy such as biogas.

[0059] The temperature of anaerobic fermentation is set to 35°C to 40°C. This temperature range is conducive to the growth and metabolic activities of anaerobic microorganisms and can accelerate the decomposition and conversion of organic matter. Within this temperature range, the enzyme activity of anaerobic microorganisms is the highest, and substrates can be used for fermentation more effectively. At the same time, this temperature also avoids the adverse effects of excessively high or low temperatures on microbial activity, ensuring the stability and sustainability of the fermentation process. Exemplarily, the temperature of anaerobic fermentation can be 35°C, 36°C, 37°C, 38°C, 39°C, and 40°C.

[0060] The time of anaerobic fermentation is set to 30d~40d (days), and the selection of this time range depends on the nature of the substrate, the activity of the microorganisms and the desired fermentation products. Longer fermentation time helps to make fuller use of the substrate for fermentation and improve the yield and quality of products such as biogas. However, too long fermentation time may also lead to increased energy consumption and an increase in the impurity content in the product. Therefore, a fermentation time of 30d~40d is a relatively reasonable choice, which can achieve higher production efficiency while ensuring product quality. Exemplary, the time of anaerobic fermentation can be 30 days, 31 days, 32 days, 33 days, 34 days, 35 days, 36 days, 37 days, 38 days, 39 days, 40 days.

[0061] In some embodiments, the biogas produced by anaerobic fermentation is stored in a biogas cabinet after the hydrogen sulfide is removed by a desulfurization tower, and is used as fuel for biogas boilers. The steam produced by the biogas boilers is used for front-end heating and insulation, ethanol distillation, etc. In some larger-scale embodiments, biogas can also be used for power generation.

[0062] S6. Purifying the biogas slurry to obtain discharge water and activated sludge;

[0063] After the biogas slurry is purified to remove harmful substances and suspended solids, it is converted into discharge water and activated sludge. The discharge water can be directly discharged after meeting the discharge standards; the activated sludge contains microorganisms and organic matter, which can be used for subsequent composting.

[0064] In this embodiment, the biogas slurry after anaerobic fermentation undergoes denitrification, nitrification, membrane filtration and other steps, and the effluent water quality reaches the reuse water quality standard or meets the discharge standard.

[0065] S7. aerobic composting the biogas residue and activated sludge to obtain a soil conditioner.

[0066] The digestate and activated sludge are fed into the aerobic composting system, where they are decomposed and transformed by microorganisms under sufficient oxygen conditions. The final product is a soil conditioner that is rich in organic matter and microorganisms and can improve soil structure and fertility.

[0067] In some embodiments, the aerobic composting treatment adopts batch fermentation treatment, and a single fermentation cycle is 7 days to 10 days. Exemplarily, a single fermentation cycle can be 7 days, 8 days, 9 days, or 10 days.

[0068] In this embodiment, the sludge generated during the treatment of biogas residue and biogas liquid is treated with auxiliary materials for aerobic composting. The composting process is batch fermentation. The biogas residue and sludge are mixed into the aerobic composting system, and auxiliary materials such as rice husks and sawdust are added. The fermentation cycle is 7 to 20 days, and the moisture content is reduced to below 45%. The product can be directly used as a soil conditioner or as a raw material for producing organic fertilizer. The composting process is equipped with a blower for mechanical air supply and an exhaust fan for forced exhaust to ensure sufficient oxygen supply during the fermentation process.

[0069] Compared with the prior art, the beneficial effects of this application are:

[0070] 1. The kitchen waste cascade utilization process of the present application adds a two-stage fermentation process of saccharification fermentation and aerobic fermentation on the basis of the anaerobic fermentation treatment process of kitchen waste. It can fully utilize the organic matter in the kitchen waste to generate by-products such as oil, ethanol, biogas, soil conditioner, etc., enrich the types of resource products, enhance the economic value of resource products, and improve the resource utilization rate of kitchen waste.

[0071] 2. In the saccharification and fermentation stage to produce ethanol, after fermentation and heating, most of the residues are decomposed into small molecules, which is helpful for subsequent reactions and effectively improves the reaction efficiency of the anaerobic fermentation stage.

[0072] 3. There is no residue to be transported out for treatment during the whole process, and the biogas produced by anaerobic fermentation can be used as fuel to produce steam or biogas power generation for use in other process links, saving energy consumption and reducing the overall cost of kitchen waste treatment.

[0073] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0074] The amount of kitchen waste treated in the following embodiments and comparative examples is ten tons.

[0075] Example

[0076] A method for recycling kitchen waste, comprising:

[0077] Step (1) Sorting and pulping: sorting and crushing the collected kitchen waste to remove impurities and prepare pulp with a size of less than 8 mm.

[0078] Step (2) three-phase separation: the kitchen waste slurry is separated into an oil phase, a solid phase and a liquid phase by a three-phase separator, wherein the oil phase is collected and transported separately.

[0079] Step (3) Saccharification and fermentation: After the three-phase separation, the solid phase and the liquid phase are mixed in a ratio of 1:1, transported to a saccharification and fermentation tank, heated to 105°C and maintained for 30 minutes to kill the bacteria therein. Cooled to 55°C, 90 (u / g) of saccharifying enzyme was added for saccharification for 4 hours, cooled to 30°C, and 10% of the active dry yeast contained in the slurry was added. After fermentation for 2 days, the slurry was sent to a distillation device to extract ethanol.

[0080] Step (4) anaerobic fermentation: the remaining liquid phase in the oil extraction step and the residue in the saccharification and fermentation step are temporarily stored in a regulating tank and then transported to an anaerobic fermentation system for continuous fermentation to produce biogas. The fermentation temperature is maintained at 40°C and the slurry hydraulic retention time is 30 days.

[0081] Step (5) biogas slurry treatment: the biogas slurry after anaerobic fermentation is sequentially subjected to denitrification, nitrification, ultrafiltration, nanofiltration, reverse osmosis and other treatment steps, and the effluent water quality reaches the reuse water quality standard or meets the discharge standard.

[0082] Step (6) aerobic composting: the activated sludge produced in the treatment process of the biogas residue and the biogas liquid is uniformly put into the slag pool for mixing and temporary storage, and then put into the aerobic fermentation device in batches, and auxiliary materials such as rice husks and sawdust are added in a ratio of about 10:3 of raw materials: auxiliary materials. The fermentation cycle is 10 days. The fermentation device is equipped with a blower for mechanical air supply and an exhaust fan for forced exhaust to ensure sufficient oxygen supply during the fermentation process.

[0083] Comparative Example 1

[0084] A method for recycling kitchen waste, comprising:

[0085] Step (1) Sorting and pulping: sorting and crushing the collected kitchen waste to remove impurities and prepare pulp with a size of less than 8 mm.

[0086] Step (2) three-phase separation: the kitchen waste slurry is separated into an oil phase, a solid phase and a liquid phase by a three-phase separator, wherein the oil phase is collected and transported separately.

[0087] Step (3) anaerobic fermentation: The liquid phase and solid phase of the oil extraction process are temporarily stored in a regulating tank and then transported to an anaerobic fermentation system for continuous fermentation to produce biogas. The fermentation temperature is maintained at 40°C and the slurry hydraulic retention time is 30 days.

[0088] The resource amounts generated by the embodiments and comparative examples are shown in the following table:

[0089]

[0090]

[0091] It can be seen from the above table that the method provided in the embodiment of the present application is used to treat kitchen waste, which can generate by-products such as biodiesel oil, ethanol, biogas, soil conditioner, etc., enriching the types of resource products, improving the economic value of resource products, and improving the resource utilization rate of kitchen waste.

[0092] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0093] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b or c" or "at least one of a, b and c" can both mean: a, b, c, a~b (i.e. a and b), a~c, b~c or a~b~c, where a, b and c can be single or multiple.

[0094] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for recycling kitchen waste, characterized in that: The method comprises: sorting and pulping the kitchen waste to obtain kitchen waste slurry; Performing three-phase separation on the kitchen waste slurry to obtain a liquid phase, an oil phase and a solid phase; Processing the oil phase to obtain biodiesel; subjecting the solid phase and part of the liquid phase to saccharification and fermentation to obtain ethanol and saccharification and fermentation residues; Anaerobic fermentation of the saccharification and fermentation residue and the remaining liquid phase to obtain biogas, biogas residue and biogas liquid; Purifying the biogas slurry to obtain discharge water and activated sludge; The biogas residue and activated sludge are subjected to aerobic composting treatment to obtain a soil conditioner.

2. The method for recycling kitchen waste according to claim 1, characterized in that: The particle size of the solid phase in the kitchen waste slurry is below 8 mm.

3. The method for recycling kitchen waste according to claim 1, characterized in that: In the saccharification and fermentation, the mass ratio of the solid phase to the liquid phase is (1-1.5):

1.

4. The method for recycling kitchen waste according to claim 1, characterized in that: The temperature of the saccharification process in the saccharification and fermentation is 55°C to 60°C; and / or The saccharification process in the saccharification and fermentation lasts for 1 hour to 5 hours.

5. The method for recycling kitchen waste according to claim 1 or 4, characterized in that: When the total amount of sugar substances in the saccharification process of the saccharification and fermentation is 1 g, the amount of saccharifying enzyme added in the saccharification process of the saccharification and fermentation is 80 u to 100 u.

6. The method for recycling kitchen waste according to claim 1, characterized in that: The fermentation temperature during the saccharification and fermentation is 28°C to 32°C; and / or The fermentation time of the saccharification and fermentation process is 1.5 days to 2 days.

7. The method for recycling kitchen waste according to claim 1 or 6, characterized in that: The inoculation amount of active dry yeast in the fermentation process of the saccharification and fermentation is 8% to 12% of the total mass of sugar content in the solid phase and the liquid phase in the slurry to be fermented.

8. The method for recycling kitchen waste according to claim 1, characterized in that: The anaerobic fermentation adopts continuous fermentation.

9. The method for recycling kitchen waste according to claim 1, characterized in that: The temperature of the anaerobic fermentation is 35°C to 40°C; and / or The anaerobic fermentation time is 30d to 40d.

10. The method for recycling kitchen waste according to claim 1, characterized in that: The aerobic composting treatment adopts batch fermentation treatment, and a single fermentation cycle is 7d to 10d.

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