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CN-121993802-A - Burn factory and burn municipal sludge treatment system in coordination based on SOFC

CN121993802ACN 121993802 ACN121993802 ACN 121993802ACN-121993802-A

Abstract

The invention relates to the technical field of garbage treatment, and provides a municipal sludge treatment system for collaborative incineration of an incineration plant based on an SOFC (solid oxide fuel cell), which comprises a garbage leachate treatment unit, an SOFC unit and a first waste heat recovery system, wherein the garbage leachate treatment unit is used for treating garbage leachate and producing sludge and methane, the SOFC unit is used for receiving and utilizing the methane produced by the garbage leachate treatment unit to generate electricity, the first waste heat recovery system is used for recovering waste heat produced by the SOFC unit and respectively providing the waste heat for the SOFC unit and the garbage leachate treatment unit for step-by-step utilization.

Inventors

  • DONG JIAN
  • ZHENG HAIXIA
  • DAI XIAODONG
  • PENG SHUJING
  • DU BING
  • ZHANG ZHENG
  • XIONG JUNXIA
  • WU HAIFENG
  • Pu Zhelong
  • CHENG HAIJING

Assignees

  • 北京首创环境科技有限公司

Dates

Publication Date
20260508
Application Date
20260106

Claims (10)

  1. 1. An SOFC-based incineration plant co-incineration municipal sludge treatment system, comprising: a landfill leachate treatment unit (1) for treating landfill leachate and producing sludge and biogas; The SOFC unit (2) is used for receiving and utilizing the biogas generated by the landfill leachate treatment unit (1) to generate electricity; And the first waste heat recovery system (3) is used for recovering waste heat generated by the SOFC unit (2) and providing the waste heat to the SOFC unit (2) and the landfill leachate treatment unit (1) respectively.
  2. 2. The SOFC-based incineration plant co-incineration municipal sludge treatment system of claim 1, further comprising: the sludge thermal hydrolysis unit (4) is used for carrying out thermal hydrolysis treatment on municipal sludge and sludge generated by the landfill leachate treatment unit (1), and the sludge thermal hydrolysis unit (4) is also connected with the first waste heat recovery system (3) and is used for receiving heat energy provided by the first waste heat recovery system (3); The plate frame dehydration unit (5), the plate frame dehydration unit (5) with mud pyrohydrolysis unit (4) is connected for carry out dehydration to the mud after the pyrohydrolysis treatment, obtain high COD clear solution and mud cake through the separation, high COD clear solution is carried to landfill leachate processing unit (1), the mud cake is carried to incineration treatment.
  3. 3. The SOFC-based incineration plant co-incineration municipal sludge treatment system according to claim 2, wherein the landfill leachate treatment unit (1) comprises: an anaerobic digestion unit (8) for decomposing macromolecular organic matters in the landfill leachate and the high COD clear liquid and generating biogas and sludge-containing wastewater; An MBR unit (9) connected with the anaerobic digestion unit (8) and used for performing denitrification and mud-water separation treatment on the produced water of the anaerobic digestion unit (8); And the membrane system (11) is connected with the MBR unit (9) and is used for treating produced water after mud-water separation of the MBR unit (9), recycling the produced water treated by the membrane system (11), and returning concentrated solution intercepted by the membrane system (11) to an incineration plant for digestion.
  4. 4. The SOFC-based incineration plant co-incineration municipal sludge treatment system of claim 3, further comprising: And the desliming unit (10), the desliming unit (10) receives part of returned sludge discharged by the MBR unit (9) and sludge discharged by the anaerobic digestion unit (8), conveys the sludge to a sludge bin after collecting treatment, and conveys the sludge to the sludge thermal hydrolysis unit (4) after mixing with external municipal sludge.
  5. 5. The SOFC-based incineration plant co-incineration municipal sludge treatment system of claim 3, further comprising: and the biogas purification system (6) is arranged between the anaerobic digestion unit (8) and the SOFC unit (2) and is used for desulfurizing and dehydrating biogas generated by the anaerobic digestion unit (8) and then sending the biogas to the SOFC unit (2).
  6. 6. The SOFC-based incineration plant co-incineration municipal sludge treatment system according to claim 5, wherein the first waste heat recovery system (3) comprises: The first heat exchanger is used for recovering heat of high-temperature exhaust gas discharged by the SOFC unit (2) and conveying the heat to the SOFC unit (2) so as to maintain a high-temperature environment required by SOFC reaction, and meanwhile, methane and air entering the SOFC unit (2) can be preheated.
  7. 7. The SOFC-based incineration plant co-incineration municipal sludge treatment system according to claim 6, wherein the first waste heat recovery system (3) further comprises: The second heat exchanger is used for recovering the heat of the medium-temperature exhaust gas after heat exchange by the first heat exchanger and conveying the heat of the medium-temperature exhaust gas to the sludge thermal hydrolysis unit (4).
  8. 8. The SOFC-based incineration plant co-incineration municipal sludge treatment system according to claim 7, wherein the first waste heat recovery system (3) further comprises: And the third heat exchanger is used for recovering the heat of the low-temperature exhaust gas after heat exchange by the second heat exchanger and preheating the mixed sludge entering the sludge thermal hydrolysis unit (4) by using the heat of the low-temperature exhaust gas.
  9. 9. The SOFC-based incineration plant co-incineration municipal sludge treatment system of claim 8, further comprising: And the second waste heat recovery system (7) is used for recovering heat discharged by the sludge thermal hydrolysis unit (4) and preheating mixed sludge to be fed into the sludge thermal hydrolysis unit (4).
  10. 10. A SOFC-based incineration plant co-incineration municipal sludge treatment system according to claim 3, characterised in that the MBR unit (9) comprises: the nitrification and denitrification subsystem is used for performing denitrification treatment on the produced water of the anaerobic digestion unit (8); The ultrafiltration unit is connected with the nitrification and denitrification system and is used for performing mud-water separation on the produced water treated by the nitrification and denitrification system, the separated sludge flows back to the nitrification and denitrification subsystem, and the produced water subjected to mud-water separation by the ultrafiltration unit enters the membrane system (11).

Description

Burn factory and burn municipal sludge treatment system in coordination based on SOFC Technical Field The invention relates to the technical field of garbage treatment, in particular to an SOFC-based municipal sludge treatment system for collaborative incineration of an incineration plant. Background The household garbage incineration treatment is used as a main mode of urban solid waste reduction and harmless treatment in China, but municipal sludge and garbage leachate which are synchronously generated in the incineration process have the problems of serious pollution and low recycling utilization due to complex components, high pollutant concentration and high treatment difficulty. Municipal sludge is an inevitable product of municipal sewage treatment plants and landfill leachate treatment systems, the water content is generally up to 80% or more, and the municipal sludge is rich in organic matters (30-50%), heavy metals (such as Zn 800-1200mg/kg and Cu 200-400 mg/kg) and pathogenic microorganisms (total bacterial count 10 8-109 CFU/g). At present, more municipal sludge is treated in a synergistic incineration mode with a household garbage incineration plant, but the high water content can greatly reduce the heat efficiency of the incinerator, and experimental data show that when the water content of the sludge is increased by 10%, the temperature of the incinerator is reduced by about 70-90 ℃, the combustion is insufficient, the generation amount of dioxin is increased by 3-5 times, meanwhile, the high chloride ion content (1500-3000 mg/L) is easy to cause equipment corrosion, the burden of a flue gas treatment system is increased, and the operation cost is increased by 20-30%. The landfill leachate is high-concentration organic wastewater generated by the landfill leachate of an incineration plant, has the typical characteristics of 20000-80000mg/L of COD (chemical oxygen demand), 1000-3000mg/L of ammonia nitrogen and 15-30mS/cm of conductivity, and has large fluctuation of water quality and water quantity and high proportion of refractory organic matters (humic acid substances account for 40-60%). The leachate is usually treated by adopting an anaerobic treatment system, an MBR (membrane biological reactor) treatment system and a membrane advanced treatment system, the generated biogas is sent to a hearth for combustion and utilization, but the utilization efficiency is low, and meanwhile, the residual sludge (the water content is 80%) is also generated in the treatment process, and the residual sludge is also sent to an incineration plant for digestion treatment, so that the treatment burden of the incineration system is increased. To solve the above problems, many technical researches have been made in the industry, but there are still significant disadvantages. For example: although the sludge thermal hydrolysis technology (such as CAMBI technology) can improve the dehydration performance of the sludge, the water content after dehydration is reduced to 45-50%, but a large amount of external heat sources are required to be consumed, the energy consumption per ton of sludge reaches 800-1000MJ, and the treatment cost is greatly increased; anaerobic digestion is a common recycling path for generating methane, but the power generation efficiency of the traditional power generation technology (such as an internal combustion engine and a steam turbine) is only 30-40%, the temperature of waste heat generated by methane combustion is low (120-180 ℃), the waste heat is difficult to recycle and the overall energy conversion efficiency is less than 45%; Solid Oxide Fuel Cells (SOFC) are used as a new generation of efficient power generation technology, can directly convert methane chemical energy into electric energy, and has power generation efficiency up to 55-65%, but has severe requirements on fuel purity (H 2 S <1ppm, water content < 5%), and needs high-temperature (600-900 ℃) operation, the existing landfill leachate has high methane impurity content and large heat value fluctuation, and can lead to electrode poisoning and rapid performance attenuation when being directly used for SOFC, and the service life of a galvanic pile is shortened to 2000-3000 hours, which is far lower than 40,000 hours required by industrial application; in addition, municipal sludge, landfill leachate and energy recovery are commonly treated as independent systems in the prior art, and a synergistic effect is lacked. According to statistics, more than 90% of garbage incineration plants nationwide adopt a mode of 'directly mixing and burning sludge and independently treating percolate', energy and material flow among systems are split, and the maximum utilization of resources cannot be realized. For example, biogas generated by percolate treatment is mostly used for boiler combustion heat supply, the energy conversion efficiency is only 35%, and the heat energy required by sludge thermal hydrolysis depends on incinerator steam