CN117736756A - Method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling - Google Patents
Method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling Download PDFInfo
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Abstract
本发明属于厨余垃圾资源化及高价值利用技术领域，公开了一种热解‑厌氧发酵耦合转化厨余垃圾的方法，包括以下步骤：基于待转化处理的厨余垃圾，获得固体残渣和油水混合物；将油水混合物进行油水分离处理，获得用于作为燃料的油脂和水相A；在固体残渣中添加生物炭催化剂，进行热解反应，获得生物炭、热解气和水相B；水相B经过有机溶剂萃取之后，与水相A混合，得到水相混合物并进行厌氧发酵，得到沼气以及包含沼渣、沼液的固液混合物。本发明公开了一种热解‑厌氧发酵耦合转化厨余垃圾为有机肥料、低氮生物油、生物炭和可燃气的工艺方法，相较于传统的处理方式可提高厨余垃圾的利用价值。
The invention belongs to the technical field of kitchen waste resource utilization and high-value utilization. It discloses a method for coupling pyrolysis-anaerobic fermentation to transform kitchen waste, which includes the following steps: based on the kitchen waste to be converted, obtain solid residue and Oil-water mixture; perform oil-water separation treatment on the oil-water mixture to obtain grease and water phase A used as fuel; add a biochar catalyst to the solid residue and perform a pyrolysis reaction to obtain biochar, pyrolysis gas and water phase B; water After phase B is extracted with an organic solvent, it is mixed with water phase A to obtain a water phase mixture and undergoes anaerobic fermentation to obtain biogas and a solid-liquid mixture including biogas residue and biogas liquid. The invention discloses a process method for coupling pyrolysis-anaerobic fermentation to convert kitchen waste into organic fertilizer, low-nitrogen bio-oil, biochar and combustible gas. Compared with traditional processing methods, the utilization value of kitchen waste can be improved. .
Description
Technical Field
The invention belongs to the technical field of recycling and high-value utilization of kitchen waste, and particularly relates to a method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling.
Background
With the acceleration of the urban development, the proportion of urban household registration population is rapidly increased; meanwhile, the output of urban garbage keeps synchronous and high-speed growth. In order to cope with the rapidly increasing urban waste yield, the number of waste incineration power plants has increased significantly in recent years.
Kitchen garbage is used as an important component of urban garbage, has the characteristics of high water content and low heat value, and is less used in garbage incineration. With the increase of environmental awareness and requirements, landfill is a harmful garbage disposal mode, and the proportion in garbage disposal is gradually reduced; at the same time, the treatment of kitchen waste has begun to shift to more environmentally friendly treatment (e.g., anaerobic fermentation, composting, biological treatment, etc.). However, the existing environment-friendly treatment method has the disadvantages of long treatment period, low input and output and difficult large-scale application.
At present, a mode of mutually matching a thermochemical method and a biological method is an efficient and environment-friendly waste resource conversion and utilization mode; wherein, the waste is subjected to rapid light-weight treatment by a thermochemical method, and then the light-weight residual part is subjected to innocent treatment by anaerobic fermentation, so that the purposes of efficient treatment and innocent digestion of the waste are achieved (for example, yang Gaixiu et al propose a treatment mode of treating biomass raw materials by using pyrolytic anaerobic coupling). However, when treating kitchen wastes with high water content and high nitrogen content, the above method cannot be effectively applied, and the main problems include:
1) The high water content of the kitchen waste means that the water in the kitchen waste needs to be dried before pyrolysis, so that a large amount of energy is consumed, and the treatment cost of the kitchen waste is obviously increased;
2) The nitrogen content of substances such as proteins in kitchen garbage is higher than that of common household garbage, so that the nitrogen content in biological oil is increased; the biological oil with high nitrogen content can release a large amount of oxynitride in the combustion process, so that the treatment cost of the biological oil combustion tail gas can be increased, and the risk of environmental pollution can be increased;
3) After pyrolysis of kitchen waste, water phase containing acid and phenolic compounds is also generated besides biological oil, and the harmless treatment of the organic compounds often requires high cost;
4) Some impurities (for example, plastics and the like) are mixed in the kitchen waste, and the impurities can obviously influence the gas production efficiency of the kitchen waste in the anaerobic fermentation process.
Disclosure of Invention
The invention aims to provide a method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which aims to solve one or more technical problems. The technical scheme provided by the invention is particularly a process method for converting kitchen waste into organic fertilizer, low-nitrogen bio-oil, biochar and combustible gas by pyrolysis-anaerobic fermentation coupling, and compared with the traditional treatment mode, the method has the advantage that the utilization value of the kitchen waste is improved.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the invention provides a method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
crushing and squeezing kitchen waste to be converted, and then carrying out solid-liquid separation to obtain solid residues and an oil-water mixture; oil-water separation treatment is carried out on the oil-water mixture, so that grease and a water phase A used as fuel are obtained;
adding a biochar catalyst into the solid residue, and performing pyrolysis reaction to obtain a biochar and gas-liquid mixture; condensing and separating the gas-liquid mixture to obtain pyrolysis gas and pyrolysis liquid;
carrying out oil-water separation treatment on the pyrolysis liquid to obtain a water phase B; the water phase B is mixed with the water phase A after being extracted by an organic solvent to obtain a water phase mixture;
and placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste in an anaerobic reactor for anaerobic fermentation to obtain biogas and a solid-liquid mixture containing biogas residue and biogas slurry.
The invention is further improved in that in the step of crushing and squeezing the kitchen waste to be converted,
the water content of the kitchen garbage filter residue after crushing and squeezing treatment is below 50wt%.
A further improvement of the present invention is that, in the step of carrying out the pyrolysis reaction,
the inert gas atmosphere of the pyrolysis reaction is argon or nitrogen atmosphere, the reaction temperature is 500-800 ℃, and the reaction time is 5-30 min.
The invention is further improved in that the biochar catalyst is a modified biochar catalyst;
wherein, the preparation steps of the modified biochar catalyst comprise: and immersing the biochar in NaOH aqueous solution for a preset time period, and calcining at a preset temperature to obtain the modified biochar catalyst.
The invention is further improved in that in the step of immersing the biochar in the aqueous NaOH solution for a preset period of time,
the concentration of NaOH in the NaOH aqueous solution is 20-60 wt%;
the preset time length is 2-6 h.
A further improvement of the invention is that, in the step of calcining at a preset temperature to obtain the modified biochar catalyst,
the preset temperature is 400-600 ℃, and the calcination time is 0.5-1 h.
A further improvement of the present invention is that the organic solvent is dichloromethane or ethyl acetate.
The invention further improves that in the step of anaerobic fermentation of the water phase mixture and the anaerobic fermentation biogas residue inoculum of kitchen waste in an anaerobic reactor,
anaerobic fermentation reaction temperature ranges from 36 ℃ to 38 ℃; the anaerobic fermentation time is 20 to 30 days under stirring; the anaerobic environment of anaerobic fermentation is nitrogen environment.
The invention further improves that in the step of anaerobic fermentation of the water phase mixture and the anaerobic fermentation biogas residue inoculum of kitchen waste in an anaerobic reactor,
the inoculation ratio of the water phase mixture to the anaerobic fermentation biogas residue inoculant of the kitchen waste is (0.2-4): 1.
A further improvement of the present invention is that,
the pyrolysis gas comprises H 2 、CO、CH 4 And CO 2 ；
The biogas comprises CH 4 And CO 2 。
Compared with the prior art, the invention has the following beneficial effects:
according to the technical scheme provided by the invention, before pyrolysis, the moisture, the grease and the solids in the kitchen waste are separated, and the water content and the nitrogen content of the kitchen waste are reduced by adopting the treatment mode; the separated oil-water mixture can be used as the raw material of anaerobic fermentation after separating the grease; the kitchen garbage residue with low water content is used as a raw material for pyrolysis to prepare high-quality bio-oil, combustible pyrolysis gas and biochar products. The aqueous layer containing phenol and acid compounds in the pyrolysis liquid can be used as a raw material for anaerobic fermentation after extracting the phenol compounds therein by using a solvent. Anaerobic fermentation simultaneously processes the water phase after the kitchen garbage is physically squeezed and the water phase after pyrolysis to generate a large amount of combustible biogas, and biogas residues and biogas slurry of organic fertilizers. In conclusion, the method for converting kitchen waste into organic fertilizer, low-nitrogen biological oil, biochar and combustible gas by pyrolysis-anaerobic fermentation coupling disclosed by the invention can greatly improve the treatment efficiency and the utilization value of the kitchen waste; the kitchen waste treatment mode of pyrolysis and anaerobic coupling can treat kitchen waste efficiently, and the defect of low efficiency of the traditional fermentation and bioconversion mode is avoided; the kitchen garbage can be pyrolyzed to produce high-quality bio-oil fuel and combustible pyrolysis gas, and the anaerobic environment can produce fertilizer and combustible biogas, so that the utilization value of the kitchen garbage is improved compared with the conventional treatment mode.
According to the invention, the steps of crushing and squeezing are added before the pyrolysis of the kitchen waste, so that nitrogen elements, moisture and grease in the kitchen waste can be separated to the greatest extent, the quality of the pyrolyzed biological oil is improved, and the heat energy loss and environmental pollution of the pyrolysis are reduced; in addition, after pyrolysis, harmful substances in kitchen waste are removed, and the rate of biogas production by anaerobic fermentation is obviously improved; and the biochar generated by the kitchen waste is directly applied to the pyrolysis process of the kitchen waste after being modified, so that the quality of the biological oil is obviously improved and the nitrogen content of the biological oil is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description of the embodiments or the drawings used in the description of the prior art will make a brief description; it will be apparent to those of ordinary skill in the art that the drawings in the following description are of some embodiments of the invention and that other drawings may be derived from them without undue effort.
FIG. 1 is a schematic flow chart of a method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling in an embodiment of the invention.
Detailed Description
The invention is further illustrated below in connection with specific examples, which are to be understood as being illustrative of the invention and not limiting the scope of the invention.
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
It should be understood that the process equipment or devices not specifically identified in the examples below are all conventional in the art.
Furthermore, it is to be understood that the reference to one or more method steps in this disclosure does not exclude the presence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise indicated; it should also be understood that the combined connection between one or more devices/means mentioned in the present invention does not exclude that other devices/means may also be present before and after the combined device/means or that other devices/means may also be interposed between these two explicitly mentioned devices/means, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the method steps is merely a convenient tool for identifying the method steps and is not intended to limit the order of arrangement of the method steps or to limit the scope of the invention in which the invention may be practiced, as such changes or modifications in their relative relationships may be regarded as within the scope of the invention without substantial modification to the technical matter.
Referring to fig. 1, the method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling provided by the embodiment of the invention comprises the following steps:
step 1, taking kitchen waste as a raw material, firstly crushing the kitchen waste, and then carrying out solid-liquid separation on crushed kitchen waste slurry through a screw press; separating grease from the liquid part through an oil-water separation device to be used as fuel, and enabling the liquid part to enter an anaerobic fermentation link; taking the rest solid residues as raw materials, adding partial biochar catalyst, and pyrolyzing by different regulation methods to generate biochar, bio-oil and pyrolysis gas; the high-temperature gas-liquid mixture generated in the pyrolysis process is cooled and separated by a condenser to obtain pyrolysis liquid and pyrolysis gas; the weight of the solid residue and biochar were collected before and after pyrolysis and the difference was used to determine the weight percent of pyrolysis products, including organic and water fractions and biochar. Further exemplary, the process of quantitatively and qualitatively analyzing the gas pyrolysis product by GC and quantitatively and qualitatively analyzing the liquid pyrolysis product by GC-MS and GC-FID is not particularly limited, and may be performed according to a well-known process in the art.
Step 2, mixing a water phase obtained after oil-water separation of the pyrolysis liquid obtained in the step 1 with a water phase obtained after squeezing and separating kitchen waste slurry obtained in the step 1 after extraction by an organic solvent to obtain a water phase mixture; meanwhile, after a part of biochar is immersed in NaOH aqueous solution for a period of time, calcining at a certain temperature to obtain a modified biochar catalyst;
and 3, mixing the water phase mixture in the step 2 with biogas residue sludge (specific exemplary, anaerobic granular sludge commodity purchased from Bida environmental protection technology Co., ltd.) remained after anaerobic fermentation of the pre-kitchen waste, and then placing the mixture in an anaerobic reactor for fermentation to obtain biogas and a solid-liquid mixture containing biogas residue and biogas slurry. Wherein, the solid-liquid mixture is used as fertilizer, and the biogas is used as combustible gas for further utilization.
The embodiment of the invention is specifically exemplified, wherein the inert gas of the pyrolysis reaction in the step 1 is argon or nitrogen, the reaction temperature is 500-800 ℃, and the residence time is 5-30 min. Further preferably, the water content of the filter residue obtained after the crushing and squeezing treatment in the step 1 is less than 50 wt%.
The embodiment of the invention is specifically exemplified, wherein the organic solvent in the step 2 is dichloromethane or ethyl acetate; more preferably, ethyl acetate is used.
The embodiment of the invention is specifically exemplified, wherein the concentration of NaOH in the aqueous solution of NaOH in the step 2 is 20-60 wt%, the soaking time is 2-6 h, the calcining temperature is 400-600 ℃, and the calcining time is 0.5-1 h.
In the embodiment of the invention, the anaerobic fermentation reaction temperature in the step 3 is preferably in the range of 37+/-1 ℃, the stirring speed is preferably 50rpm, and the time is 0-45 days, preferably 20-30 days.
The embodiment of the invention is specifically exemplified, the anaerobic environment in the step 3 is preferably a nitrogen environment, and the inoculation ratio of the water phase mixture to the inoculum is (0.2-4): 1; further preferably 2:1.
In the embodiment of the invention, the pyrolysis gas in the step 1 mainly comprises H 2 、CO、CH 4 And CO 2 . In addition, the biogas in the step 3 is mainly CH 4 And CO 2 。
The method for converting kitchen waste into organic fertilizer, low-nitrogen bio-oil, biochar and combustible gas through pyrolysis-anaerobic fermentation coupling disclosed by the embodiment of the invention can greatly improve the treatment efficiency and the utilization value of the kitchen waste; the kitchen waste treatment mode of pyrolysis and anaerobic coupling can treat kitchen waste efficiently, and the defect of low efficiency of the traditional fermentation and bioconversion mode is avoided; the kitchen garbage can be pyrolyzed to produce high-quality bio-oil fuel and combustible pyrolysis gas, and the anaerobic environment can produce fertilizer and combustible biogas, so that the utilization value of the kitchen garbage is improved compared with the conventional treatment mode.
Example 1
The embodiment of the invention provides a process method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
step 1, taking kitchen waste as a raw material, firstly crushing the kitchen waste, and then carrying out solid-liquid separation on crushed kitchen waste slurry through a screw press; the liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen; the bio-oil yield was 52.4wt%, the biochar yield was 24.9wt% and the pyrolysis gas yield was 22.7wt%. Elemental analysis and detection show that the nitrogen content in the pyrolyzed produced biological oil is 2.01 percent, and the calorific value is 44.34MJ/kg;
step 2, mixing a water phase obtained after oil-water separation of the pyrolysis liquid obtained in the step 1 with a water phase obtained after squeezing and separating kitchen waste slurry obtained in the step 1 after extraction of ethyl acetate to obtain a water phase mixture; immersing the biochar obtained in the step 1 in 50wt% NaOH aqueous solution for 2 hours, and calcining the filtered and dried biochar at 500 ℃ for 0.5 hour to obtain a modified biochar catalyst;
step 3, placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste into an anaerobic reactor for fermentation; the process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 574mL/gVS fs 。
Example 2
In the embodiment of the invention, kitchen waste is taken as a raw material, firstly crushed, and then the crushed kitchen waste slurry is dried; the pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 49.2wt%, the bio-char yield was 27.6wt%, and the pyrolysis gas yield was 23.2wt%. The elemental analysis detection shows that the nitrogen content in the pyrolysis produced bio-oil is 5.78%, and the heat value is 41.80MJ/kg.
As can be seen from the comparison of the embodiment 1 and the embodiment 2, the steps of crushing and squeezing greatly reduce the nitrogen content in the kitchen waste, improve the yield and the heat value of the pyrolysis oil of the kitchen waste, and remarkably improve the economic value of the heat value of the kitchen waste.
Example 3
The embodiment of the invention provides a process method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
step 1, taking kitchen waste as a raw material, firstly crushing the kitchen waste, and then carrying out solid-liquid separation on crushed kitchen waste slurry through a screw press; the liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 52.4wt%, the biochar yield was 24.9wt% and the pyrolysis gas yield was 22.7wt%. Elemental analysis and detection show that the nitrogen content in the pyrolyzed produced biological oil is 2.01 percent, and the calorific value is 44.34MJ/kg;
and 2, extracting the water phase obtained after oil-water separation of the pyrolysis liquid obtained in the step 1, and mixing the water phase with the water phase obtained after squeezing and separating the kitchen waste slurry obtained in the step 1 to obtain a water phase mixture. Immersing the biochar obtained in the step 1 in 50wt% NaOH aqueous solution for 2 hours, and calcining the filtered and dried biochar at 500 ℃ for 0.5 hour to obtain a modified biochar catalyst;
step 3, placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste into an anaerobic reactor for fermentation; wherein the process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the overall methane yield was 363mL/gVS fs 。
Example 4
The embodiment of the invention provides a process method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
step 1, taking kitchen waste as a raw material, firstly crushing the kitchen waste, and then carrying out solid-liquid separation on crushed kitchen waste slurry through a screw press; the liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 52.4wt%, the biochar yield was 24.9wt% and the pyrolysis gas yield was 22.7wt%. Elemental analysis and detection show that the nitrogen content in the pyrolyzed produced biological oil is 2.01 percent, and the calorific value is 44.34MJ/kg;
and 2, mixing a water phase obtained after oil-water separation of the pyrolysis liquid obtained in the step 1 with a water phase obtained after squeezing and separating kitchen waste slurry in the step 1 after extracting phenolic compounds by using methylene dichloride to obtain a water phase mixture. Immersing the biochar obtained in the step 1 in 50wt% NaOH aqueous solution for 2 hours, and calcining the filtered and dried biochar at 500 ℃ for 0.5 hour to obtain a modified biochar catalyst;
and 3, placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste into an anaerobic reactor for fermentation. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. At fortyFive days, the total methane yield was 571mL/gVS fs 。
As can be seen from examples 1, 3 and 4, the extraction of phenolic compounds in the aqueous phase of the pyrolysis liquid by the solvent has a significant promoting effect on the subsequent anaerobic fermentation, and the use of both dichloromethane and ethyl acetate has a significant promoting effect.
Example 5
The embodiment of the invention provides a process method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
step 1, taking kitchen waste as a raw material, firstly crushing the kitchen waste, and then carrying out solid-liquid separation on crushed kitchen waste slurry through a screw press; the liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 52.4wt%, the biochar yield was 24.9wt% and the pyrolysis gas yield was 22.7wt%. Elemental analysis and detection show that the nitrogen content in the pyrolyzed produced biological oil is 2.01 percent, and the calorific value is 44.34MJ/kg;
and 2, extracting phenolic compounds from the water phase obtained by oil-water separation of the pyrolysis liquid obtained in the step 1 by using ethyl acetate, and mixing the water phase with the water phase obtained by squeezing and separating the kitchen waste slurry obtained in the step 1 to obtain a water phase mixture. Immersing the biochar obtained in the step 1 in 50wt% NaOH aqueous solution for 2 hours, and calcining the filtered and dried biochar at 500 ℃ for 0.5 hour to obtain a modified biochar catalyst;
and 3, placing the water phase mixture, the kitchen waste and anaerobic fermentation biogas residue inoculum of the kitchen waste in an anaerobic reactor for fermentation. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 544mL/gVS fs 。
Example 6
In the embodiment of the invention, the anaerobic fermentation biogas residue inoculum of the kitchen waste and the kitchen waste is placed in an anaerobic reactor to enterAnd (5) fermenting. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 295mL/gVS fs 。
According to the embodiments 1, 5 and 6, the water phase mixture of the water phase and the filtrate after pyrolysis treatment can produce more methane in anaerobic fermentation, so that the utilization efficiency and the value of kitchen waste in anaerobic fermentation are obviously improved.
Example 7
In the embodiment of the invention, kitchen waste, plastic particles with the mass ratio of 10wt% of the kitchen waste and anaerobic fermentation biogas residue inoculums of the kitchen waste are placed in an anaerobic reactor for fermentation. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 312mL/gVS fs 。
Example 8
In the embodiment of the invention, kitchen garbage and impurity particles (bones, chopsticks and the like) with the mass ratio of 10wt% are placed in an anaerobic reactor for fermentation. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 274mL/gVS fs 。
Example 9
The embodiment of the invention provides a process method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
step 1, kitchen waste and plastic particles with the mass ratio of 10wt% are taken as raw materials, the raw materials are crushed, and then solid-liquid separation is carried out on the crushed slurry through a screw press. The liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 52.7wt%, the biochar yield was 21.7wt% and the pyrolysis gas yield was 25.6wt%. Elemental analysis and detection show that the nitrogen content in the pyrolyzed produced biological oil is 1.69%, and the heat value is 45.13MJ/kg;
and 2, mixing the water phase obtained after oil-water separation of the pyrolysis liquid obtained in the step 1 with the water phase obtained after squeezing and separating the kitchen waste slurry obtained in the step 1 after extraction of ethyl acetate to obtain a water phase mixture. Immersing the biochar obtained in the step 1 in 50wt% NaOH aqueous solution for 2 hours, and calcining the filtered and dried biochar at 500 ℃ for 0.5 hour to obtain a modified biochar catalyst;
and 3, placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste into an anaerobic reactor for fermentation. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 577mL/gVS fs 。
Example 10
The embodiment of the invention provides a process method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling, which comprises the following steps:
step 1, kitchen garbage and 10wt% of impurity particles (bones, chopsticks and the like) are taken as raw materials, the raw materials are firstly crushed, and then solid-liquid separation is carried out on the crushed slurry through a screw press. The liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the modified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 46.4wt%, the bio-char yield was 35.6wt% and the pyrolysis gas yield was 18.0wt%. The elemental analysis detection shows that the nitrogen content in the pyrolysis produced bio-oil is 2.14%, and the calorific value is 44.71MJ/kg.
And 2, mixing the water phase obtained after oil-water separation of the pyrolysis liquid obtained in the step 1 with the water phase obtained after squeezing and separating the kitchen waste slurry obtained in the step 1 after extraction of ethyl acetate to obtain a water phase mixture. The biochar obtained in the step 1 was immersed in 50wt% naoh aqueous solution for 2 hours, and then the filtered and dried biochar was calcined at 500 ℃ for 0.5 hour to obtain a modified biochar catalyst.
And 3, placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste into an anaerobic reactor for fermentation. The process is carried out at 37.+ -. 1 ℃ and the stirring speed is preferably 50rpm for 45 days. On forty-five days, the total methane yield was 580mL/gVS fs 。
From examples 1 and 6 to 10, it is clear that impurities and plastics have a certain influence on the direct anaerobic fermentation; however, after pyrolysis treatment, the negative influence is eliminated, which shows that the process method disclosed by the invention has good adaptability to sources and components of kitchen waste, and can be suitable for treating kitchen waste with different components.
Example 11
In the embodiment of the invention, kitchen garbage and 10wt% of impurity particles (bones, chopsticks and the like) are taken as raw materials, the raw materials are firstly crushed, and then solid-liquid separation is carried out on the crushed slurry through a screw squeezer. The liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue without adding the biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 44.9wt%, the biochar yield was 37.2wt% and the pyrolysis gas yield was 17.9wt%. The elemental analysis detection shows that the nitrogen content in the pyrolysis produced bio-oil is 3.25%, and the calorific value is 43.16MJ/kg.
Example 12
In the embodiment of the invention, kitchen garbage and 10wt% of impurity particles (bones, chopsticks and the like) are taken as raw materials, the raw materials are firstly crushed, and then solid-liquid separation is carried out on the crushed slurry through a screw squeezer. The liquid part separates grease out through an oil-water separation device to be used as fuel, and the liquid part enters an anaerobic fermentation link. The pyrolysis temperature of the solid residue added with the unmodified biochar catalyst is 500 ℃, the retention time is 5 minutes, the heating rate is 10 ℃/min, the flow is 100mL/min, and the hot carrier gas is nitrogen. The bio-oil yield was 45.7wt%, the bio-char yield was 36.6wt% and the pyrolysis gas yield was 17.7wt%. The elemental analysis detection shows that the nitrogen content in the pyrolysis produced bio-oil is 2.93 percent and the calorific value is 43.61MJ/kg.
As can be seen from examples 10 to 12, the modified biochar catalyst significantly increased the calorific value of the bio-oil and reduced the nitrogen content in the element.
Example 13
The method for converting kitchen waste through pyrolysis-anaerobic fermentation coupling provided by the embodiment of the invention comprises the following steps:
crushing and squeezing kitchen waste to be converted, and then carrying out solid-liquid separation to obtain solid residues and an oil-water mixture; oil-water separation treatment is carried out on the oil-water mixture, so that grease and a water phase A used as fuel are obtained; adding a biochar catalyst into the solid residue, and performing pyrolysis reaction to obtain a biochar and gas-liquid mixture; condensing and separating the gas-liquid mixture to obtain pyrolysis gas and pyrolysis liquid; carrying out oil-water separation treatment on the pyrolysis liquid to obtain a water phase B; the water phase B is mixed with the water phase A after being extracted by an organic solvent to obtain a water phase mixture; placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste into an anaerobic reactor for anaerobic fermentation to obtain biogas and a solid-liquid mixture containing biogas residue and biogas slurry;
wherein the water content of the kitchen waste filter residue after crushing and squeezing treatment is below 50wt%; the inert gas atmosphere of the pyrolysis reaction is argon atmosphere, the reaction temperature is 500 ℃, and the reaction time is 5min; the biochar catalyst is a modified biochar catalyst, and the preparation method comprises the following steps: immersing the biochar in NaOH aqueous solution for a preset time period, and calcining at a preset temperature to obtain the modified biochar catalyst; the concentration of NaOH in the NaOH aqueous solution is 20wt%; the preset time length is 2 hours; the preset temperature is 400 ℃, and the calcination time is 0.5h; the organic solvent is dichloromethane; anaerobic fermentation reaction temperature range is 36 ℃; the anaerobic fermentation time is 20 days under stirring; the anaerobic environment of anaerobic fermentation is a nitrogen environment; the inoculation ratio of the water phase mixture to the anaerobic fermentation biogas residue inoculum of the kitchen waste is 2:1.
The invention is trueIn an embodiment, the pyrolysis gas obtained comprises mainly H 2 、CO、CH 4 And CO 2 The method comprises the steps of carrying out a first treatment on the surface of the The obtained biogas mainly comprises CH 4 And CO 2 。
Example 14
The difference between the embodiment of the invention and the embodiment 13 is that the inert gas atmosphere of the pyrolysis reaction is nitrogen atmosphere, the reaction temperature is 700 ℃, and the reaction time is 20min; the biochar catalyst is a modified biochar catalyst, and the preparation method comprises the following steps: immersing the biochar in NaOH aqueous solution for a preset time period, and calcining at a preset temperature to obtain the modified biochar catalyst; the concentration of NaOH in the NaOH aqueous solution is 40wt%; the preset time length is 4 hours; the preset temperature is 500 ℃, and the calcination time is 0.75h; the organic solvent is ethyl acetate; anaerobic fermentation reaction temperature range is 37 ℃; the anaerobic fermentation time is 25 days under stirring; the inoculation ratio of the water phase mixture to the anaerobic fermentation biogas residue inoculum of the kitchen waste is 0.2:1.
In the embodiment of the invention, the obtained pyrolysis gas mainly comprises H 2 、CO、CH 4 And CO 2 The method comprises the steps of carrying out a first treatment on the surface of the The obtained biogas mainly comprises CH 4 And CO 2 。
Example 15
The difference between the examples of the present invention and example 13 is that the reaction temperature was 800℃and the reaction time was 30min; the biochar catalyst is a modified biochar catalyst, and the preparation method comprises the following steps: immersing the biochar in NaOH aqueous solution for a preset time period, and calcining at a preset temperature to obtain the modified biochar catalyst; the concentration of NaOH in the NaOH aqueous solution is 60wt%; the preset time length is 6 hours; the preset temperature is 600 ℃, and the calcination time is 1h; the organic solvent is ethyl acetate; anaerobic fermentation reaction temperature range is 38 ℃; the anaerobic fermentation time is 30 days under stirring; the inoculation ratio of the water phase mixture to the anaerobic fermentation biogas residue inoculum of the kitchen waste is 4:1.
In the embodiment of the invention, the obtained pyrolysis gas mainly comprises H 2 、CO、CH 4 And CO 2 The method comprises the steps of carrying out a first treatment on the surface of the The obtained biogas mainly comprises CH 4 And CO 2 。
Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.
Claims (10)
1. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling is characterized by comprising the following steps of:
crushing and squeezing kitchen waste to be converted, and then carrying out solid-liquid separation to obtain solid residues and an oil-water mixture; oil-water separation treatment is carried out on the oil-water mixture, so that grease and a water phase A used as fuel are obtained;
adding a biochar catalyst into the solid residue, and performing pyrolysis reaction to obtain a biochar and gas-liquid mixture; condensing and separating the gas-liquid mixture to obtain pyrolysis gas and pyrolysis liquid;
carrying out oil-water separation treatment on the pyrolysis liquid to obtain a water phase B; the water phase B is mixed with the water phase A after being extracted by an organic solvent to obtain a water phase mixture;
and placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste in an anaerobic reactor for anaerobic fermentation to obtain biogas and a solid-liquid mixture containing biogas residue and biogas slurry.
2. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein in the step of crushing and squeezing kitchen waste to be converted,
the water content of the kitchen garbage filter residue after crushing and squeezing treatment is below 50wt%.
3. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein in the step of performing pyrolysis reaction,
the inert gas atmosphere of the pyrolysis reaction is argon or nitrogen atmosphere, the reaction temperature is 500-800 ℃, and the reaction time is 5-30 min.
4. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein the biochar catalyst is a modified biochar catalyst;
wherein, the preparation steps of the modified biochar catalyst comprise: and immersing the biochar in NaOH aqueous solution for a preset time period, and calcining at a preset temperature to obtain the modified biochar catalyst.
5. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 4, wherein in the step of immersing the biochar in NaOH aqueous solution for a preset period of time,
the concentration of NaOH in the NaOH aqueous solution is 20-60 wt%;
the preset time length is 2-6 h.
6. The method for converting kitchen waste by coupling pyrolysis and anaerobic fermentation according to claim 4, wherein in the step of calcining at a predetermined temperature to obtain the modified biochar catalyst,
the preset temperature is 400-600 ℃, and the calcination time is 0.5-1 h.
7. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein the organic solvent is dichloromethane or ethyl acetate.
8. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein in the step of placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste in an anaerobic reactor for anaerobic fermentation,
anaerobic fermentation reaction temperature ranges from 36 ℃ to 38 ℃; the anaerobic fermentation time is 20 to 30 days under stirring; the anaerobic environment of anaerobic fermentation is nitrogen environment.
9. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein in the step of placing the water phase mixture and the anaerobic fermentation biogas residue inoculum of the kitchen waste in an anaerobic reactor for anaerobic fermentation,
the inoculation ratio of the water phase mixture to the anaerobic fermentation biogas residue inoculant of the kitchen waste is (0.2-4): 1.
10. The method for converting kitchen waste by pyrolysis-anaerobic fermentation coupling according to claim 1, wherein,
the pyrolysis gas comprises H 2 、CO、CH 4 And CO 2 ；
The biogas comprises CH 4 And CO 2 。
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| CN119930333A (en) * | 2024-12-31 | 2025-05-06 | 生态环境部华南环境科学研究所(生态环境部生态环境应急研究所) | A method for recycling low-carbon and zero-emission kitchen waste oil-fertilizer co-production |
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| CN119930333A (en) * | 2024-12-31 | 2025-05-06 | 生态环境部华南环境科学研究所(生态环境部生态环境应急研究所) | A method for recycling low-carbon and zero-emission kitchen waste oil-fertilizer co-production |
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