Resource comprehensive utilization treatment method for municipal sludge and kitchen waste

Abstract

The invention discloses a recycling comprehensive utilization treatment method of municipal sludge and kitchen waste, which comprises the following steps: mixing and crushing municipal sludge, kitchen waste and alkaline residue, and heating under an ultrasonic condition to obtain pretreated waste; injecting waste gas containing carbon dioxide into the pretreated waste, and uniformly stirring to obtain acid treated waste; then adding a microelectrolysis material into the acid treated waste, applying a pulsed magnetic field for treatment while performing ultrasonic oscillation, performing hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry and biogas residues, and further drying and carbonizing the biogas residues to obtain the biochar. According to the invention, resource comprehensive utilization of municipal sludge and kitchen waste is realized, high-quality biogas, biogas slurry and biochar are finally obtained, and the application prospect is good.

Description

Technical Field

[0001] The invention relates to a sludge treatment method, in particular to a resource comprehensive utilization treatment method for urban sludge and kitchen waste. Background Art

[0002] Municipal sludge and food waste are both common pollution problems in cities.

[0003] Municipal sludge is produced during sewage treatment, with a water content of 60-80%, high organic content, strong odor, difficult to stack, and easy to rot and stink. At present, municipal sludge is usually treated by landfill or incineration. Landfill will occupy a large amount of precious land resources, and will pollute groundwater and surrounding land, accompanied by stench and affect the surrounding environment; incineration will produce fly ash, which is dangerous, and dioxins produced by incineration will cause secondary pollution.

[0004] The composition of restaurant kitchen waste is complex, with high content of organic matter such as starch, food fiber, animal fat, etc., including grease, rice, flour, vegetables, fruit peels, fish, meat, bones, etc. In addition, the water content of restaurant kitchen waste is as high as 80-95%, and the salt content is also high. It is very easy to spoil and breed pathogenic microorganisms, which is extremely harmful. At present, except for pig breeding, most of the restaurant kitchen waste is disposed of in the form of landfill, which occupies a large amount of precious land resources, and will pollute groundwater and surrounding land, and the stench will affect the surrounding environment.

[0005] Municipal sewage sludge and food waste are usually treated separately, but in fact, the two have certain commonalities, such as high water content and high organic matter content. Therefore, it is reasonable to treat municipal sewage sludge and food waste together, which can save resources, reduce treatment costs and has high promotion value.

[0006] Patent CN102887736B discloses a method for producing special fertilizer by processing kitchen waste and sludge with domestic waste in the same machine. When the organic matter of domestic waste enters the pulping machine, the slurry of the kitchen waste after the non-degradable matter is sorted out is added to the feed port of the machine together with an appropriate amount of water, so that the two types of waste are mixed into a fine slurry, and then the sludge is added and stirred evenly; after removing heavy metals, decomposing dioxins, and conducting deep anaerobic fermentation of microorganisms, and then dehydrating and mixing materials, high-temperature mineralization reaction fermentation is carried out to obtain raw fertilizer, and then a dual coordination production process is used to produce microbial organic fertilizer. This patented technology relies on the improvement of processing equipment, and the transformation cost is high, which limits further promotion and application.

[0007] Patent CN110116126B discloses a method for the coordinated disposal of kitchen waste and sludge, which obtains biogas and biogas liquid by fine pulping, slag and impurity removal, grease recovery, and anaerobic digestion of kitchen waste, thereby reducing the amount of kitchen waste and obtaining biomass energy; and the sludge and biogas residue are jointly conditioned, dried, carbonized, and carbonized, so that the sludge and biogas residue achieve the four goals; when the kitchen waste is anaerobic digested alone, the excess biogas generated is used for power generation, purification and compression or burned by a torch, and the excess biogas is introduced into the drying and carbonization system as a supplementary heat source, thereby improving the energy utilization efficiency. However, the water squeezing effect of this patented technology cannot be guaranteed, which directly affects the subsequent resource utilization effect (carbonization effect, biogas quality, etc.). Summary of the invention

[0008] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a method for comprehensive resource utilization of urban sewage sludge and kitchen waste.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0011] (1) firstly, mixing urban sludge, restaurant kitchen waste and alkaline residue, crushing them, and heating them under ultrasonic conditions to obtain pretreated waste;

[0012] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0013] (3) Then, micro-electrolysis materials are added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonic oscillation is performed, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0014] Preferably, in step (1), the mass ratio of municipal sludge, kitchen waste and alkaline residue is 10:5-7:2-3.

[0015] Preferably, in step (1), the mixture is crushed to a size of 100 to 200 meshes.

[0016] Preferably, in step (1), the alkali residue is waste residue discharged during the alkali production process using the ammonia-soda process.

[0017] Preferably, in step (1), the ultrasonic oscillation power is 500-700 W, the heating temperature is 60-70° C., and the treatment time is 50-60 minutes.

[0018] Preferably, in step (2), the waste gas containing carbon dioxide is selected from any one of the following emissions: an incinerator, a steelmaking furnace, a boiler, a combustion furnace, and a hot blast furnace.

[0019] Preferably, in step (2), the volume content of carbon dioxide in the waste gas is 30-40%.

[0020] Preferably, in step (2), the temperature of the exhaust gas is 200-300°C, the injection pressure is 0.1-0.2 MPa, and the injection speed is 15-20 m / s. 3 / min, and each kg of pretreated waste is injected for 2 to 3 minutes.

[0021] Preferably, in step (2), the exhaust gas is injected from the bottom of the pretreated waste.

[0022] Preferably, in step (2), the stirring process conditions are: stirring at 300-400 r / min for 40-50 minutes.

[0023] Preferably, in step (3), the mass ratio of the acid-treated waste to the micro-electrolysis material is 17-20:0.1-0.2.

[0024] Preferably, in step (3), the micro-electrolytic material is prepared by mixing iron powder, graphite powder, manganese dioxide, nickel chloride and ammonium chloride as raw materials.

[0025] Further preferably, the micro-electrolytic material is prepared by the following method, measured in parts by weight: first, 6 to 7 parts of iron powder, 1.5 to 2 parts of graphite powder, 0.5 to 0.7 parts of manganese dioxide, 0.03 to 0.05 parts of nickel chloride, and 0.06 to 0.08 parts of ammonium chloride are mixed evenly, and then 5 to 6 parts of water are added to mix well, and small balls with a diameter of 3 to 5 mm are formed by a ball forming machine, dried, heated to 400 to 420°C, roasted for 10 to 12 minutes, continued to heat to 1050 to 1100°C, roasted for 15 to 20 minutes, and naturally cooled to room temperature.

[0026] Preferably, in step (3), the ultrasonic oscillation power is 500-600W; the process conditions of the pulsed magnetic field are: magnetic field intensity 3-5T, pulse width 200-300ms, pulse frequency 50-70Hz; and the treatment time is 8-10 minutes.

[0027] Preferably, in step (3), the process conditions of the hydrothermal treatment are: temperature 120-140° C., pressure 0.1-0.2 MPa, and time 50-60 minutes.

[0028] Preferably, in step (3), the anaerobic fermentation time is 3 to 5 days.

[0029] Preferably, in step (3), the biochar is prepared by the following method: in a nitrogen atmosphere, the biogas residue is first dried at 120-130°C for 2-3 hours, then the temperature is increased to 500-520°C at a rate of 2-3°C / min, and pyrolyzed for 30-40 minutes.

[0030] Beneficial effects of the present invention:

[0031] The present invention first mixes and crushes urban sludge, restaurant kitchen waste and alkaline residue, and heats and treats them under ultrasonic conditions to obtain pre-treated waste; injects waste gas containing carbon dioxide into the pre-treated waste, stirs it evenly, and obtains acid-treated waste; then adds micro-electrolysis material to the acid-treated waste, applies pulsed magnetic field treatment while ultrasonic oscillation, hydrothermally treats, and performs anaerobic fermentation to obtain biogas, biogas liquid and biogas residue, and the biogas residue is further dried and carbonized to obtain biochar. The present invention realizes the comprehensive resource utilization of urban sludge and restaurant kitchen waste, and finally obtains high-quality biogas, biogas liquid and biochar, and has good application prospects.

[0032] In addition to urban sludge and kitchen waste, the present invention further introduces alkali residue and waste gas containing carbon dioxide, thereby realizing the recycling of waste and being green and environmentally friendly.

[0033] Under the action of alkali residue, with the help of ultrasonic oscillation and heating, urban sludge and kitchen waste are initially degraded, reducing the difficulty of subsequent treatment. Injecting waste gas containing carbon dioxide into the pre-treated waste for acid treatment can further degrade the pollutants in the system and reduce the difficulty of subsequent treatment.

[0034] The present invention uses iron powder, graphite powder, manganese dioxide, nickel chloride and ammonium chloride as raw materials to mix and prepare micro-electrolysis materials. Under the coupling effect of ultrasonic oscillation and magnetic field treatment, the micro-electrolysis materials can fully adsorb and treat pollutants, and effectively improve the quality of biogas and biogas liquid obtained by anaerobic fermentation.

[0035] The sludge is further dried and carbonized to obtain biochar, thereby achieving full utilization of the three forms of gas, liquid and solid, and realizing the comprehensive resource utilization of urban sludge and kitchen waste. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with embodiments. It should be noted that the following description is only for explaining the present invention and does not limit its contents.

[0037] Embodiment 1:

[0038] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0039] (1) 100 kg of municipal sludge, 50 kg of restaurant kitchen waste and 20 kg of alkali residue were mixed and crushed to 100 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0040] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0041] (3) Then, micro-electrolysis materials are added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonic oscillation is performed, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0042] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0043] The ultrasonic oscillation power was 500 W, the heating temperature was 60° C., and the treatment time was 50 minutes.

[0044] In step (2), the waste gas containing carbon dioxide is discharged from an incinerator, and the volume content of carbon dioxide in the waste gas is 30%.

[0045] The exhaust gas temperature is 200°C, the injection pressure is 0.1MPa, and the injection speed is 15m 3 / min, with each kg of pretreated waste injected for 2 minutes.

[0046] Exhaust gas is injected from the bottom of the pre-treated waste.

[0047] The stirring process conditions are: stirring at 300r / min for 40 minutes.

[0048] In step (3), the mass ratio of acid-treated waste to micro-electrolysis material is 17:0.1.

[0049] The micro-electrolytic material is prepared by the following method: first, 6 kg of iron powder, 1.5 kg of graphite powder, 0.5 kg of manganese dioxide, 0.03 kg of nickel chloride, and 0.06 kg of ammonium chloride are evenly mixed, and then 5 kg of water is added to mix well, and small balls with a diameter of 3 mm are made using a ball forming machine, and then dried, heated to 400°C, roasted for 10 minutes, continued to heat to 1050°C, roasted for 15 minutes, and naturally cooled to room temperature.

[0050] The ultrasonic oscillation power is 500W; the process conditions of the pulse magnetic field are: magnetic field intensity 3T, pulse width 200ms, pulse frequency 50Hz; and the processing time is 8 minutes.

[0051] The process conditions of the hydrothermal treatment are: temperature 120°C, pressure 0.1MPa, and time 50 minutes.

[0052] The anaerobic fermentation time is 3 days.

[0053] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 120°C for 2 hours, then heated to 500°C at a rate of 2°C / min, and pyrolyzed for 30 minutes.

[0054] Embodiment 2:

[0055] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0056] (1) 100 kg of municipal sludge, 70 kg of restaurant kitchen waste and 30 kg of alkali residue were mixed and crushed to 200 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0057] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0058] (3) Then, micro-electrolysis materials are added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonic oscillation is performed, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0059] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0060] The ultrasonic oscillation power was 700 W, the heating temperature was 70° C., and the treatment time was 60 minutes.

[0061] In step (2), the waste gas containing carbon dioxide is discharged from an incinerator, and the volume content of carbon dioxide in the waste gas is 40%.

[0062] The exhaust gas temperature is 300°C, the injection pressure is 0.2MPa, and the injection speed is 20m 3 / min, with each kg of pretreated waste injected for 3 minutes.

[0063] Exhaust gas is injected from the bottom of the pre-treated waste.

[0064] The stirring process conditions are: stirring at 400r / min for 50 minutes.

[0065] In step (3), the mass ratio of the acid-treated waste to the micro-electrolysis material is 20:0.2.

[0066] The micro-electrolytic material is prepared by the following method: first, 7 kg of iron powder, 2 kg of graphite powder, 0.7 kg of manganese dioxide, 0.05 kg of nickel chloride, and 0.08 kg of ammonium chloride are evenly mixed, and then 6 kg of water is added to mix well, and small balls with a diameter of 5 mm are formed by a ball forming machine, and then dried, heated to 420°C, roasted for 12 minutes, continued to heat to 1100°C, roasted for 20 minutes, and naturally cooled to room temperature.

[0067] The ultrasonic oscillation power is 600W; the process conditions of the pulse magnetic field are: magnetic field intensity 5T, pulse width 300ms, pulse frequency 70Hz; and the processing time is 10 minutes.

[0068] The process conditions of the hydrothermal treatment are: temperature 140°C, pressure 0.2MPa, and time 60 minutes.

[0069] The anaerobic fermentation time is 5 days.

[0070] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 130°C for 3 hours, then heated to 520°C at a rate of 3°C / min, and pyrolyzed for 40 minutes.

[0071] Embodiment 3:

[0072] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0073] (1) 100 kg of municipal sludge, 50 kg of restaurant kitchen waste and 30 kg of alkali residue were mixed and crushed to 100 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0074] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0075] (3) Then, micro-electrolysis materials are added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonic oscillation is performed, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0076] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0077] The ultrasonic oscillation power was 700 W, the heating temperature was 60° C., and the treatment time was 60 minutes.

[0078] In step (2), the waste gas containing carbon dioxide is discharged from an incinerator, and the volume content of carbon dioxide in the waste gas is 30%.

[0079] The exhaust gas temperature is 300°C, the injection pressure is 0.1MPa, and the injection speed is 20m 3 / min, with each kg of pretreated waste injected for 2 minutes.

[0080] Exhaust gas is injected from the bottom of the pre-treated waste.

[0081] The stirring process conditions are: stirring at 400r / min for 40 minutes.

[0082] In step (3), the mass ratio of the acid-treated waste to the micro-electrolysis material is 20:0.1.

[0083] The micro-electrolytic material is prepared by the following method: first, 7 kg of iron powder, 1.5 kg of graphite powder, 0.7 kg of manganese dioxide, 0.03 kg of nickel chloride, and 0.08 kg of ammonium chloride are evenly mixed, and then 5 kg of water is added to mix well, and small balls with a diameter of 5 mm are made using a ball forming machine, and then dried, heated to 400°C, roasted for 12 minutes, continued to heat to 1050°C, roasted for 20 minutes, and naturally cooled to room temperature.

[0084] The ultrasonic oscillation power is 500W; the process conditions of the pulse magnetic field are: magnetic field intensity 5T, pulse width 200ms, pulse frequency 70Hz; and the processing time is 8 minutes.

[0085] The process conditions of the hydrothermal treatment are: temperature 140°C, pressure 0.1MPa, and time 60 minutes.

[0086] The anaerobic fermentation time is 3 days.

[0087] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 130°C for 2 hours, then heated to 500°C at a rate of 3°C / min, and pyrolyzed for 40 minutes.

[0088] Embodiment 4:

[0089] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0090] (1) 100 kg of municipal sludge, 60 kg of restaurant kitchen waste and 25 kg of alkali residue were mixed and crushed to 200 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0091] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0092] (3) Then, micro-electrolysis materials are added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonic oscillation is performed, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0093] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0094] The ultrasonic oscillation power was 600 W, the heating temperature was 65° C., and the treatment time was 55 minutes.

[0095] In step (2), the waste gas containing carbon dioxide is discharged from an incinerator, and the volume content of carbon dioxide in the waste gas is 35%.

[0096] The exhaust gas temperature is 250°C, the injection pressure is 0.2MPa, and the injection speed is 18m 3 / min, with each kg of pretreated waste injected for 2 minutes.

[0097] Exhaust gas is injected from the bottom of the pre-treated waste.

[0098] The stirring process conditions are: stirring at 400r / min for 45 minutes.

[0099] In step (3), the mass ratio of acid-treated waste to micro-electrolysis material is 18:0.15.

[0100] The micro-electrolytic material is prepared by the following method: first, 6.5 kg of iron powder, 1.8 kg of graphite powder, 0.6 kg of manganese dioxide, 0.04 kg of nickel chloride, and 0.07 kg of ammonium chloride are evenly mixed, and then 5.5 kg of water is added to mix well, and small balls with a diameter of 4 mm are made using a ball forming machine, and then dried, heated to 410°C, roasted for 11 minutes, continued to heat to 1080°C, roasted for 17 minutes, and naturally cooled to room temperature.

[0101] The ultrasonic oscillation power was 500 W; the process conditions of the pulse magnetic field were: magnetic field intensity 4 T, pulse width 300 ms, pulse frequency 60 Hz; and the processing time was 9 minutes.

[0102] The process conditions of the hydrothermal treatment are: temperature 130°C, pressure 0.2MPa, and time 55 minutes.

[0103] The anaerobic fermentation time is 4 days.

[0104] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 125°C for 2.5 hours, then heated to 510°C at a rate of 2.5°C / min, and pyrolyzed for 35 minutes.

[0105] Comparative Example 1

[0106] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0107] (1) 100 kg of municipal sludge, 50 kg of restaurant kitchen waste and 20 kg of alkali residue were mixed and crushed to 100 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0108] (2) Then, micro-electrolysis materials are added to the pretreated waste, and pulsed magnetic field treatment is applied while ultrasonic oscillation is performed, hydrothermal treatment is performed, and anaerobic fermentation is performed to obtain biogas, biogas liquid, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0109] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0110] The ultrasonic oscillation power was 500 W, the heating temperature was 60° C., and the treatment time was 50 minutes.

[0111] In step (2), the mass ratio of the pretreated waste to the micro-electrolysis material is 17:0.1.

[0112] The micro-electrolytic material is prepared by the following method: first, 6 kg of iron powder, 1.5 kg of graphite powder, 0.5 kg of manganese dioxide, 0.03 kg of nickel chloride, and 0.06 kg of ammonium chloride are evenly mixed, and then 5 kg of water is added to mix well, and small balls with a diameter of 3 mm are made using a ball forming machine, and then dried, heated to 400°C, roasted for 10 minutes, continued to heat to 1050°C, roasted for 15 minutes, and naturally cooled to room temperature.

[0113] The ultrasonic oscillation power is 500W; the process conditions of the pulse magnetic field are: magnetic field intensity 3T, pulse width 200ms, pulse frequency 50Hz; and the processing time is 8 minutes.

[0114] The process conditions of the hydrothermal treatment are: temperature 120°C, pressure 0.1MPa, and time 50 minutes.

[0115] The anaerobic fermentation time is 3 days.

[0116] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 120°C for 2 hours, then heated to 500°C at a rate of 2°C / min, and pyrolyzed for 30 minutes.

[0117] Comparative Example 2

[0118] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0119] (1) 100 kg of municipal sludge, 50 kg of restaurant kitchen waste and 20 kg of alkali residue were mixed and crushed to 100 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0120] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0121] (3) The acid-treated waste is then subjected to ultrasonic oscillation and pulsed magnetic field treatment, hydrothermal treatment, and anaerobic fermentation to obtain biogas, biogas liquid, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0122] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0123] The ultrasonic oscillation power was 500 W, the heating temperature was 60° C., and the treatment time was 50 minutes.

[0124] In step (2), the waste gas containing carbon dioxide is discharged from an incinerator, and the volume content of carbon dioxide in the waste gas is 30%.

[0125] The exhaust gas temperature is 200°C, the injection pressure is 0.1MPa, and the injection speed is 15m 3 / min, with each kg of pretreated waste injected for 2 minutes.

[0126] Exhaust gas is injected from the bottom of the pre-treated waste.

[0127] The stirring process conditions are: stirring at 300r / min for 40 minutes.

[0128] In step (3), the ultrasonic oscillation power is 500W; the process conditions of the pulsed magnetic field are: magnetic field intensity 3T, pulse width 200ms, pulse frequency 50Hz; and the processing time is 8 minutes.

[0129] The process conditions of the hydrothermal treatment are: temperature 120°C, pressure 0.1MPa, and time 50 minutes.

[0130] The anaerobic fermentation time is 3 days.

[0131] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 120°C for 2 hours, then heated to 500°C at a rate of 2°C / min, and pyrolyzed for 30 minutes.

[0132] Comparative Example 3

[0133] A method for comprehensive resource utilization of urban sewage sludge and kitchen waste, the specific steps are as follows:

[0134] (1) 100 kg of municipal sludge, 50 kg of restaurant kitchen waste and 20 kg of alkali residue were mixed and crushed to 100 meshes, and then heated under ultrasonic conditions to obtain pretreated waste;

[0135] (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the pre-treated waste to obtain acid-treated waste;

[0136] (3) Then, micro-electrolysis materials are added to the acid-treated waste, and ultrasonic oscillation treatment, hydrothermal treatment, and anaerobic fermentation are performed to obtain biogas, biogas slurry, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

[0137] Wherein, in step (1), the alkali residue is the waste residue discharged during the alkali production process using the ammonia-soda process.

[0138] The ultrasonic oscillation power was 500 W, the heating temperature was 60° C., and the treatment time was 50 minutes.

[0139] In step (2), the waste gas containing carbon dioxide is discharged from an incinerator, and the volume content of carbon dioxide in the waste gas is 30%.

[0140] The exhaust gas temperature is 200°C, the injection pressure is 0.1MPa, and the injection speed is 15m 3 / min, with each kg of pretreated waste injected for 2 minutes.

[0141] Exhaust gas is injected from the bottom of the pre-treated waste.

[0142] The stirring process conditions are: stirring at 300r / min for 40 minutes.

[0143] In step (3), the mass ratio of acid-treated waste to micro-electrolysis material is 17:0.1.

[0144] The micro-electrolytic material is prepared by the following method: first, 6 kg of iron powder, 1.5 kg of graphite powder, 0.5 kg of manganese dioxide, 0.03 kg of nickel chloride, and 0.06 kg of ammonium chloride are evenly mixed, and then 5 kg of water is added to mix well, and small balls with a diameter of 3 mm are made using a ball forming machine, and then dried, heated to 400°C, roasted for 10 minutes, continued to heat to 1050°C, roasted for 15 minutes, and naturally cooled to room temperature.

[0145] The ultrasonic oscillation power was 500 W and the treatment time was 8 minutes.

[0146] The process conditions of the hydrothermal treatment are: temperature 120°C, pressure 0.1MPa, and time 50 minutes.

[0147] The anaerobic fermentation time is 3 days.

[0148] The biochar was prepared by the following method: in a nitrogen atmosphere, the biogas residue was first dried at 120°C for 2 hours, then heated to 500°C at a rate of 2°C / min, and pyrolyzed for 30 minutes.

[0149] Test example

[0150] Relevant tests were performed on the biogas, biogas slurry and biochar obtained in Examples 1 to 4 and Comparative Examples 1 to 3, respectively, as follows:

[0151] 1. Biogas: record the biogas production (biogas production per ton of total weight of urban sludge and food waste) and detect the methane content (volume) in the biogas.

[0152] 2. Biogas slurry: detect the COD content, ammonia nitrogen content and total phosphorus content in the biogas slurry.

[0153] Among them, COD is measured using a COD detector; ammonia nitrogen concentration is measured with reference to HJ 536-2009 "Determination of ammonia nitrogen in water quality-Salicylic acid spectrophotometry"; total phosphorus content is measured with reference to GB 11893-89 "Determination of total phosphorus in water quality-Ammonium molybdate spectrophotometry".

[0154] 3. Biochar: Use an elemental analyzer to determine the carbon content (mass) of biochar.

[0155] The test results are shown in Tables 1 to 3.

[0156] Table 1. Statistics of biogas production and methane content in biogas

[0157]

[0158]

[0159] As can be seen from Table 1, Examples 1 to 4 have high biogas production, high methane content and good quality.

[0160] Table 2. Biogas slurry testing

[0161] COD(mg / L) Ammonia nitrogen (mg / L) Total phosphorus (mg / L) Example 1 2050 1425 1050 Example 2 2056 1428 1055 Example 3 2062 1432 1061 Example 4 2075 1455 1072 Comparative Example 1 2218 1102 825 Comparative Example 2 2156 1155 907 Comparative Example 3 2207 1169 985

[0162] It can be seen from Table 2 that the biogas slurries obtained in Examples 1 to 4 have high COD content, ammonia nitrogen content, and total phosphorus content, and can be used as liquid fertilizers.

[0163] Table 3. Carbon content of biochar

[0164] Carbon content of biochar (%) Example 1 73.2 Example 2 73.5 Example 3 73.9 Example 4 74.8 Comparative Example 1 67.3 Comparative Example 2 67.5 Comparative Example 3 68.1

[0165] It can be seen from Table 3 that the biochars obtained in Examples 1 to 4 have high carbon content and good quality.

[0166] In Comparative Example 1, the acid treatment step was omitted, in Comparative Example 2, the micro-electrolysis material was omitted, and in Comparative Example 3, the pulsed magnetic field treatment was omitted. The biogas production was low, the methane content in the biogas was low, the ammonia nitrogen content and the total phosphorus content in the biogas slurry were low, the carbon content of the biochar was low, and the resource utilization effect was poor, indicating that the acid treatment, the addition of the micro-electrolysis material and the pulsed magnetic field treatment work synergistically to achieve better comprehensive resource utilization.

[0167] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A method for comprehensive resource utilization of urban sludge and kitchen waste, characterized in that: The specific steps are as follows: (1) First, municipal sludge, kitchen waste and alkali residue are mixed and crushed, and then heated under ultrasonic conditions to obtain pretreated waste; (2) injecting waste gas containing carbon dioxide into the pre-treated waste and stirring the waste evenly to obtain acid-treated waste; (3) Then, micro-electrolysis materials are added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonic oscillation is performed, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas slurry and biogas residue. The biogas residue is further dried and carbonized to obtain biochar.

2. The method according to claim 1, characterized in that In step (1), the mass ratio of urban sludge, kitchen waste and alkali residue is 10:5-7:2-3.

3. The method according to claim 1, characterized in that In step (1), the ultrasonic oscillation power is 500-700 W, the heating temperature is 60-70° C., and the treatment time is 50-60 minutes.

4. The method according to claim 1, characterized in that: In step (2), the waste gas containing carbon dioxide is selected from any of the following emissions: an incinerator, a steelmaking furnace, a boiler, a combustion furnace, and a hot blast furnace; The volume content of carbon dioxide in the waste gas is 30-40%.

5. The method according to claim 1, characterized in that In step (2), the temperature of the exhaust gas is 200-300°C, the injection pressure is 0.1-0.2 MPa, and the injection speed is 15-20 m / s. 3 / min, and each kg of pretreated waste is injected for 2 to 3 minutes.

6. The method according to claim 1, characterized in that In step (2), the stirring process conditions are: stirring at 300-400 r / min for 40-50 minutes.

7. The method according to claim 1, characterized in that In step (3), the mass ratio of the acid-treated waste to the micro-electrolysis material is 17-20:0.1-0.

2.

8. The method according to claim 1, characterized in that In step (3), the micro-electrolytic material is prepared by mixing iron powder, graphite powder, manganese dioxide, nickel chloride and ammonium chloride as raw materials.

9. The method according to claim 1, characterized in that: In step (3), the ultrasonic oscillation power is 500-600W; the process conditions of the pulsed magnetic field are: magnetic field intensity 3-5T, pulse width 200-300ms, pulse frequency 50-70Hz; treatment time 8-10 minutes; The process conditions of hydrothermal treatment are: temperature 120-140°C, pressure 0.1-0.2MPa, time 50-60 minutes; The anaerobic fermentation time is 3 to 5 days.

10. The method according to claim 1, characterized in that In step (3), the biochar is prepared by the following method: in a nitrogen atmosphere, the biogas residue is first dried at 120-130°C for 2-3 hours, then the temperature is increased to 500-520°C at a rate of 2-3°C / min, and pyrolyzed for 30-40 minutes.

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