A method for comprehensive resource utilization of urban sewage sludge and kitchen waste

Abstract

The present invention discloses a method for comprehensive resource utilization of municipal sludge and kitchen waste. The method comprises the following steps: first, the municipal sludge, kitchen waste, and alkaline residue are mixed and crushed, and then heated under ultrasonic conditions to obtain pre-treated waste; waste gas containing carbon dioxide is injected into the pre-treated waste, and the mixture is stirred evenly to obtain acid-treated waste; then, a micro-electrolysis material is added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonically oscillating the waste, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas liquid, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar. The present invention realizes the comprehensive resource utilization of municipal sludge and kitchen waste, ultimately obtaining high-quality biogas, biogas liquid, and biochar, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to a sludge treatment method, in particular to a resource-based 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. It typically contains 60-80% water, is high in organic matter, and has a strong odor, making it difficult to store and prone to spoilage. Currently, landfill or incineration are commonly used to dispose of municipal sludge. Landfilling consumes valuable land resources, pollutes groundwater and surrounding land, and produces foul odors that impact the surrounding environment. Incineration also produces dangerous fly ash, and the dioxins it produces can cause secondary pollution.

[0004] Food waste is complex, high in organic matter like starch, dietary fiber, and animal fat. It includes oils, rice, flour, vegetables, fruit peels, fish, meat, and bones. Furthermore, it contains 80-95% water and a high salt content, making it highly susceptible to spoilage and breeding pathogens, posing a significant risk. Currently, aside from pig farming, most food waste is landfilled, consuming valuable land resources, polluting groundwater and surrounding land, and creating a foul odor that impacts the surrounding environment.

[0005] Municipal 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 sludge and food waste together, and it can save resources, reduce treatment costs, and has high promotion value.

[0006] Patent CN102887736B discloses a method for producing specialized fertilizer by processing food waste, sludge, and domestic waste simultaneously. While the organic matter from the domestic waste enters a pulping machine, the crushed food waste, after sorting out the non-degradable materials, is added to the machine's feed port along with an appropriate amount of water. The two types of waste are mixed to form a fine slurry, and the sludge is then added and stirred evenly. After removing heavy metals, decomposing dioxins, and conducting deep anaerobic microbial fermentation, the materials are then dehydrated and mixed with bacteria to prepare the mixture. High-temperature mineralization reaction and fermentation are then carried out to obtain the raw fertilizer, and a dual-coordination production process is then used to produce microbial organic fertilizer. This patented technology relies on improvements to the processing equipment, resulting in high modification costs, which limits its further application.

[0007] Patent CN110116126B discloses a method for the coordinated disposal of food waste and sludge. By subjecting food waste to refined pulping, slag and impurity removal, grease recovery, and anaerobic digestion, biogas and biogas liquid are produced, reducing food waste while generating biomass energy. Furthermore, the sludge and biogas residue are jointly conditioned, dried, carbonized, and carbonized, achieving the four goals of recycling the sludge and biogas residue. When the food waste is anaerobic digested alone, the excess biogas generated is used for power generation, purification and compression, or flared. The excess biogas is then fed into the drying and carbonization systems as a supplementary heat source, improving energy efficiency. However, this patented technology fails to guarantee water extraction, directly impacting subsequent resource utilization (carbonization efficiency, biogas quality, etc.). Summary of the Invention

[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for comprehensive resource utilization of municipal 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 municipal sludge and kitchen waste, comprising the following steps:

[0011] (1) First, municipal sludge, restaurant kitchen waste and alkaline residue are mixed and crushed, and then heated under ultrasonic conditions to obtain pretreated waste;

[0012] (2) injecting waste gas containing carbon dioxide into the pretreated waste and stirring the 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 liquid, 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, restaurant kitchen waste and alkaline residue is 10:5-7:2-3.

[0015] Preferably, in step (1), the mixture is crushed to 100-200 mesh.

[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 500-700W, 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 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, 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 thoroughly, and small balls with a diameter of 3 to 5 mm are formed using a ball forming machine, dried, heated to 400 to 420°C, and roasted for 10 to 12 minutes, and then heated 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: under a nitrogen atmosphere, the biogas residue is first dried at 120-130°C for 2-3 hours, then heated 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 pulverizes municipal sludge, restaurant kitchen waste, and alkaline residue, then heats them under ultrasonic conditions to produce pretreated waste. Exhaust gas containing carbon dioxide is injected into the pretreated waste, and the mixture is stirred evenly to produce acid-treated waste. Micro-electrolysis materials are then added to the acid-treated waste, and a pulsed magnetic field is applied while ultrasonically oscillating the waste. Hydrothermal treatment and anaerobic fermentation are then performed to produce biogas, biogas liquid, and biogas residue. The biogas residue is then dried and carbonized to produce biochar. This method achieves the comprehensive resource utilization of municipal sludge and restaurant kitchen waste, ultimately producing high-quality biogas, biogas liquid, and biochar, and has promising 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 alkaline residue, ultrasonic vibration and heating are used to initially degrade municipal sludge and food waste, reducing the difficulty of subsequent treatment. Injecting waste gas containing carbon dioxide into the pre-treated waste for acid treatment can further degrade pollutants in the system, reducing 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, effectively improving 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 food waste. DETAILED DESCRIPTION

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

[0037] Example 1:

[0038] A method for comprehensive resource utilization of municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, and then heated under ultrasonic conditions to obtain pretreated waste;

[0040] (2) injecting waste gas containing carbon dioxide into the pretreated waste and stirring the 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 liquid, 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 of 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℃, the injection pressure is 0.1MPa, and the injection speed is 15m 3 / min, and each kg of pretreated waste is injected for 2 minutes.

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

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

[0048] In step (3), the mass ratio of the acid-treated waste to the 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 mixed evenly, and then 5 kg of water is added to mix evenly. The small balls with a diameter of 3 mm are made using a ball forming machine, dried, heated to 400 ° C, and roasted for 10 minutes. The material is further heated to 1050 ° C, roasted for 15 minutes, and naturally cooled to room temperature.

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

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

[0052] The anaerobic fermentation time is 3 days.

[0053] Biochar was prepared by the following method: under 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] Example 2:

[0055] A method for comprehensive resource utilization of municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, and then heated under ultrasonic conditions to obtain pretreated waste;

[0057] (2) injecting waste gas containing carbon dioxide into the pretreated waste and stirring the 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 liquid, 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 of 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℃, the injection pressure is 0.2MPa, and the injection speed is 20m 3 / min, and each kg of pretreated waste is 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 400 r / 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 mixed evenly, and then 6 kg of water is added to mix evenly. The small balls with a diameter of 5 mm are made using a ball forming machine, dried, heated to 420 ° C, and roasted for 12 minutes. The material is further heated to 1100 ° C and roasted for 20 minutes, and naturally cooled to room temperature.

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

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

[0069] The anaerobic fermentation time is 5 days.

[0070] Biochar was prepared by the following method: under 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] Example 3:

[0072] A method for comprehensive resource utilization of municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, and then heated under ultrasonic conditions to obtain pretreated waste;

[0074] (2) injecting waste gas containing carbon dioxide into the pretreated waste and stirring the 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 liquid, 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 of 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℃, the injection pressure is 0.1MPa, and the injection speed is 20m 3 / min, and each kg of pretreated waste is 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 400 r / 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 mixed evenly, and then 5 kg of water is added to mix evenly. The small balls with a diameter of 5 mm are made using a ball forming machine, dried, heated to 400 ° C, and roasted for 12 minutes. The material is further heated to 1050 ° C and roasted for 20 minutes, and naturally cooled to room temperature.

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

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

[0086] The anaerobic fermentation time is 3 days.

[0087] Biochar was prepared by the following method: under 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] Example 4:

[0089] A method for comprehensive resource utilization of municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, and then heated under ultrasonic conditions to obtain pretreated waste;

[0091] (2) injecting waste gas containing carbon dioxide into the pretreated waste and stirring the 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 liquid, 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 of 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℃, the injection pressure is 0.2MPa, and the injection speed is 18m 3 / min, and each kg of pretreated waste is 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 400 r / min for 45 minutes.

[0099] In step (3), the mass ratio of the acid-treated waste to the 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 mixed evenly, and then 5.5 kg of water is added to mix evenly. The small balls with a diameter of 4 mm are made using a ball forming machine, and the small balls are dried, heated to 410°C, and roasted for 11 minutes. The small balls are further heated to 1080°C and roasted for 17 minutes, and then naturally cooled to room temperature.

[0101] The ultrasonic oscillation power was 500 W; the process conditions of the pulsed 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 0.2 MPa, and time 55 minutes.

[0103] The anaerobic fermentation time is 4 days.

[0104] Biochar was prepared by the following method: under 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 municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, 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, 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 of 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 mixed evenly, and then 5 kg of water is added to mix evenly. The small balls with a diameter of 3 mm are made using a ball forming machine, dried, heated to 400 ° C, and roasted for 10 minutes. The material is further heated to 1050 ° C, roasted for 15 minutes, and naturally cooled to room temperature.

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

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

[0115] The anaerobic fermentation time is 3 days.

[0116] Biochar was prepared by the following method: under 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 municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, and then heated under ultrasonic conditions to obtain pretreated waste;

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

[0121] (3) The acid-treated waste is then subjected to ultrasonic oscillation while being subjected to a pulsed magnetic field, hydrothermal treatment, and anaerobic fermentation to obtain biogas, biogas liquid, and biogas residue, which is then 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 of 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℃, the injection pressure is 0.1MPa, and the injection speed is 15m 3 / min, and each kg of pretreated waste is injected for 2 minutes.

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

[0127] The stirring process conditions are: 300r / min stirring 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 0.1 MPa, and time 50 minutes.

[0130] The anaerobic fermentation time is 3 days.

[0131] Biochar was prepared by the following method: under 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 municipal sludge and kitchen waste, comprising the following steps:

[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 mesh, and then heated under ultrasonic conditions to obtain pretreated waste;

[0135] (2) injecting waste gas containing carbon dioxide into the pretreated waste and stirring the 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 liquid, 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 of 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℃, the injection pressure is 0.1MPa, and the injection speed is 15m 3 / min, and each kg of pretreated waste is injected for 2 minutes.

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

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

[0143] In step (3), the mass ratio of the acid-treated waste to the 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 mixed evenly, and then 5 kg of water is added to mix evenly. The small balls with a diameter of 3 mm are made using a ball forming machine, dried, heated to 400 ° C, and roasted for 10 minutes. The material is further heated to 1050 ° C, roasted for 15 minutes, and naturally cooled to room temperature.

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

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

[0147] The anaerobic fermentation time is 3 days.

[0148] Biochar was prepared by the following method: under 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] The biogas, biogas liquid and biochar obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were tested, as follows:

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

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

[0153] Among them, COD is measured using a COD detector; ammonia nitrogen concentration is measured with reference to HJ 536-2009 "Water quality - Determination of ammonia nitrogen - Salicylic acid spectrophotometry"; total phosphorus content is measured with reference to GB 11893-89 "Water quality - Determination of total phosphorus - 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] As shown in Table 2, 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] As shown in Table 3, 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, the micro-electrolysis material was omitted, and 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 liquid 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 municipal sludge and kitchen waste, characterized in that: The specific steps are as follows: (1) First, municipal sludge, restaurant 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 pretreated waste and stirring the waste 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 applied, followed by hydrothermal treatment and anaerobic fermentation to obtain biogas, biogas liquid, and biogas residue. The biogas residue is further dried and carbonized to obtain biochar; In step (3), the micro-electrolytic material is prepared by the following method, calculated 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 evenly, and small balls with a diameter of 3 to 5 mm are formed by a ball forming machine, and the small balls are dried, heated to 400 to 420° C., and roasted for 10 to 12 minutes, and then heated to 1050 to 1100° C. and roasted for 15 to 20 minutes, and then naturally cooled to room temperature to obtain the micro-electrolytic material; The process conditions of the pulsed magnetic field are: magnetic field intensity 3 to 5 T, pulse width 200 to 300 ms, pulse frequency 50 to 70 Hz; and processing time 8 to 10 minutes.

2. The method according to claim 1, characterized in that In step (1), the mass ratio of municipal sludge, restaurant 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 500-700W, the heating temperature is 60-70°C, and the treatment time is 50-60 minutes.

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

5. The method according to claim 1, wherein 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 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: 300-400 r / min stirring 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.

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8. The method according to claim 1, characterized in that In step (3), the ultrasonic oscillation power is 500-600W; The process conditions of hydrothermal treatment are: temperature 120-140°C, pressure 0.1-0.2 MPa, time 50-60 minutes; The anaerobic fermentation time is 3 to 5 days.

9. 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 heated to 500-520°C at a rate of 2-3°C / min, and pyrolyzed for 30-40 minutes.

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