CN111233290A - Sludge treatment system for sewage treatment plant - Google Patents

Abstract

The invention discloses a sludge treatment system for a sewage treatment plant, which comprises a sludge concentration tank. The sludge concentration tank is divided into A pool and B pool. A pool passes through a pipeline sludge incinerator; B pool passes through a sludge incinerator. The pipeline is connected to the anaerobic fermentation tank in turn, part of the steam of the sludge incinerator is transported to the heat exchanger through the pipeline, and the low temperature liquid of the heat exchanger is circulated through the pipeline with the interlayer of the anaerobic fermentation tank and the pipeline of the solar heat collector; The gas outlet of the oxygen fermentation tank is connected to the cogeneration device through a pipeline, and another part of the steam from the sludge incinerator is transported to the cogeneration device through a pipeline, and the cogeneration device is electrically connected to the power output device. The invention can process a large amount of excess sludge, the biomass energy in the sludge can be used for power generation, and the residue after sludge treatment can be used as fertilizer to achieve the purposes of sludge "reduction", "stabilization" and "resource utilization".

Description

A sludge treatment system for a sewage treatment plant

technical field

The invention belongs to the technical field of environmental protection, and in particular relates to a sludge treatment system for a sewage treatment plant.

Background technique

In recent years, the number and treatment capacity of urban sewage treatment plants in my country have increased rapidly, but there is a common problem of high operating costs, mainly due to high power consumption, which generally accounts for about 50% of the entire operating costs.

Due to the phenomenon of "heavy water and light mud" in my country for a long time, insufficient attention has been paid to sludge treatment. A large amount of sludge has not been stabilized and disposed of, causing environmental pollution and endangering human health. How to dispose of sludge reasonably and realize the reduction, harmlessness and resource utilization of sludge economically and effectively is an important issue faced by governments, enterprises and environmental protection workers all over the world. The construction and operation of the sewage treatment plant is accompanied by the production of a large amount of excess sludge. Based on the moisture content of 80%, the total annual sludge production in the country will soon exceed 30 million tons. According to the forecast, the sludge production will exceed 60 million tons per year by 2020.

As the government and citizens attach importance to environmental protection, people begin to notice the potential of biomass energy. Sewage treatment plants produce a large amount of sludge every day. The sludge contains organic matter. Under the action of anaerobic microorganisms, macromolecular organic matter is decomposed into stable substances. , compared with the sludge before digestion, the volume can be greatly reduced, and at the same time, methane-based biogas can be obtained. There are still nutrients in the residue after anaerobic digestion, and it can also be used as fertilizer or soil conditioner, which can maximize resource utilization and achieve the goals of "reduction", "stabilization" and "resource utilization". However, how to utilize the renewable resources of the sewage treatment plant to achieve high-efficiency power generation is a technical problem in the art.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a sludge treatment system for a sewage treatment plant, which can process a large amount of excess sludge, and the biomass energy in the sludge can be used for power generation, The residue after sludge treatment is used as fertilizer to achieve the purpose of "reduction", "stabilization" and "resource utilization" of sludge.

The technical problem to be solved by the present invention is achieved through such a technical solution, which includes a sludge thickening tank, a solar heat collector, a heat exchanger, an anaerobic fermentation tank and a cogeneration device. The sludge thickening tank is divided into A Pool and Pool B, Pool A is connected to the plate and frame filter press, sludge drying room and sludge incinerator in sequence through pipelines; Pool B is connected to the anaerobic fermentation tank, biogas slurry and biogas residue collector and separator in sequence through pipelines; Part of the steam of the sludge incinerator is transported to the heat exchanger through the pipeline, and the low-temperature liquid of the heat exchanger is circulated through the pipeline with the interlayer of the anaerobic fermentation tank and the pipeline of the solar heat collector; the gas outlet of the anaerobic fermentation tank is successively connected through the pipeline. The gas storage chamber, biogas desulfurizer, biogas purifier and methane compressor are connected to the gas turbine of the cogeneration unit. Another part of the steam from the sludge incinerator is transported to the steam turbine generator of the cogeneration unit through pipelines. The device is electrically connected to the power output device.

Compared with the prior art, the technical effect of the present invention is:

It can treat a large amount of excess sludge in the sewage treatment plant, and use the energy generated by biomass energy to supply the plate and frame filter press to achieve the purpose of treating waste with waste; the invention realizes the simultaneous treatment of sludge and odor in the sewage treatment plant, High treatment efficiency, energy saving and environmental protection, greatly reducing the treatment and discharge pressure of excess sludge; the biogas produced by the anaerobic digestion of sludge not only meets the energy required for self-fermentation, but can also be supplied to the cogeneration unit; in addition, the anaerobic digestion of sludge produces The biogas slurry and biogas residues have been fermented to kill pathogenic bacteria and parasite eggs, and can be used as organic fertilizer; the energy generated by sludge drying and incineration can be supplied to heat exchangers and cogeneration devices, realizing the “reduction of excess sludge”. The purpose of "stabilization", "resourceization" and "resourceization".

Description of drawings

The accompanying drawings of the present invention are described as follows:

FIG. 1 is a technical roadmap of an embodiment of the present invention;

2 is a schematic structural diagram of an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of the cogeneration device in FIG. 2 .

In the figure, 1, sludge thickening tank; 2, plate and frame filter press; 3, sludge drying room; 4, sludge incinerator; 5, solar heat collector; 6, heat exchanger; 7, anaerobic fermentation Tank; 8. Gas storage chamber; 9. Biogas desulfurizer; 10. Biogas purifier; 11. Methane compressor; 12. Gas turbine; 13. Motor; 14. Smoke exhauster; 15. Waste heat boiler; 16. Steam turbine generator Electrical appliances; 17. Power output device; 18. Biogas slurry and residue collector; 19. Separator; 20. Cogeneration device.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:

As shown in Figure 1, the technical route of the present invention is that the entire system is divided into two parts: a sludge resource utilization module and a biomass power supply module: the sludge resource utilization module includes a sludge thickening tank, and the sludge thickening tank passes through a pipeline The plate and frame filter press, the sludge drying room and the sludge incinerator are connected in sequence, and the anaerobic fermentation tank, the biogas slurry and residue collector and separator, the heat exchanger and the solar heat collector are connected in sequence through another pipeline. Both are connected to the anaerobic fermenter to provide the fermenter with the heat required for fermentation. The biomass power supply module includes a gas storage chamber, a biogas desulfurizer, a biogas purifier, a methane compressor, a heat exchanger, a cogeneration device and a battery.

The sludge thickening tank is divided into A pool and B pool by the retaining wall, A pool sludge accounts for 30%, B pool sludge accounts for 70%. The sludge thickening tank A pool is connected with the plate and frame filter press through the pipeline, and the sludge anaerobic fermentation tank is connected with the sludge thickening tank B pool through the pipeline; the excess sludge in the sludge thickening tank A pool is passed through the plate and frame filter press. After filter press and dehydration, it enters the rotary drum dryer in the sludge drying room. The sludge is fully contacted with the hot air under the stirring of the rotary drum frying plate, and the moisture content of the sludge is controlled below 40%, and then transported to the sludge. Incinerators, the heat generated by incineration is supplied to heat exchangers and cogeneration systems. The sludge thickening tank B is connected to the anaerobic fermentation tank. The biogas generated by the anaerobic fermentation tank enters the gas storage room for storage, and the biogas is transported to the biogas desulfurizer to be desulfurized by the high-pressure water washing process, and then purified by the biogas purifier and compressed by the methane compressor. , and finally sent to the cogeneration unit to generate electricity. At the same time, the biogas slurry and biogas residue in the anaerobic fermentation tank are collected by the collector, and the liquid fertilizer and biogas residue are separated by the separator.

In pool B, the residual sludge of the sewage treatment plant and a small amount of landfill leachate are mixed in proportion to form a mixed sludge with a C/N ratio of 10-20:1; Fe ₃ O of 50-150 mg/g VS is added to the mixed sludge. ₄ and 30～50mg/g VS ZVI (zero-valent iron), while promoting the hydrolysis of organic matter in the sludge, reducing the redox potential of the subsequent fermentation system, and also acting as a conductive material to promote the interspecific electrons between acetylating microorganisms and methanogens The transfer process; the diameter of the ZVI (zero-valent iron) is about 0.15mm, and the purity is greater than 80%; the diameter of the Fe ₃ O ₄ is about 0.15mm, and the purity is greater than 62% in terms of iron content.

The anaerobic fermentation tank adopts a double-layer egg-shaped structure. The egg-shaped structure has good stress conditions, and at the same time, the stirring is sufficient and there is no dead angle. The sludge is not easy to consolidate at the bottom of the tank. The interlayer of the double-egg-shaped anaerobic fermenter is filled with heated and insulated water. When the double-egg type anaerobic fermenter adopts medium temperature fermentation, the organic load is generally about 1.6-6.4kgVSS/(m ³ •d), and the hydraulic retention time is longer, and the residence time is 10-15d. The double-egg-shaped anaerobic fermenter uses solar collectors and heat exchangers to provide the required heat for mesophilic fermentation.

The solar collector is composed of all-glass mirrors, solar collectors, temperature sensors, etc. The heat is absorbed by the solar heat collector and transported to the interlayer of the double-layer egg-shaped fermentation tank to adjust the temperature to ensure normal gas production under the condition of low external air temperature. Condenser reflection adopts all-glass specular mirror reflection, which has high optical efficiency. The solar collector adopts forced circulation, with high photothermal efficiency, and the system efficiency can reach 60% to 80%.

The heat generated by the sludge incinerator boils the water, 5% to 10% of the steam is supplied to the heat exchanger, and 90% to 95% of the steam is supplied to the cogeneration unit.

Cogeneration units include gas turbines, generators, smoke extractors, waste heat boilers and steam turbine generators. The air inlet of the gas turbine is connected with the air outlet of the methane compressor through a pipeline. The compressed methane and air enter the gas turbine, mix and burn in the combustion chamber, and then expand in the steam turbine to drive the impeller to rotate, so that it drives the generator to generate electricity. The exhaust gas temperature of the gas turbine is very high (generally above 500 ℃), which is an excellent driving heat source. The high temperature exhaust gas is exhausted through the smoke exhauster for waste heat recovery, and the waste heat boiler generates steam, which makes the steam continue to do work in the steam turbine generator. generate electricity. The steam generated by the sludge incinerator will also enter the steam turbine generator to generate power. The total thermal efficiency of the cogeneration unit can reach 75%-82%.

The cogeneration device is connected to the power output device, and the generated electrical energy is supplied to the power grid or electrical appliances through the power output device to provide the required power for the plate and frame filter press, the park lighting system, and the odor absorption and treatment device.

As shown in FIG. 2 , this embodiment includes a sludge thickening tank 1, a solar heat collector 5, a heat exchanger 6, an anaerobic fermentation tank 7 and a cogeneration device 20. The sludge thickening tank 1 is divided into A pool and Pool B and Pool A are connected to the plate and frame filter press 2, the sludge drying room 3 and the sludge incinerator 4 in sequence through pipelines; Pool B is connected to the anaerobic fermentation tank 7, the biogas slurry and residue collector 18 and the Separator 19; a part of the steam of the sludge incinerator 4 is transported to the heat exchanger 6 through the pipeline, and the low-temperature liquid of the heat exchanger 6 is circulated through the pipeline with the interlayer of the anaerobic fermentation tank 7 and the pipeline of the solar heat collector 5; The gas outlet of the oxygen fermentation tank 7 is sequentially connected to the gas storage chamber 8, the biogas desulfurizer 9, the biogas purifier 10 and the methane compressor 11 through pipelines, and supplies gas to the gas turbine 12 of the cogeneration device 20, and the other side of the sludge incinerator 4. A portion of the steam is piped to the steam turbine generator 16 of the cogeneration unit 20 , which is electrically connected to the power output 17 .

The anaerobic fermentation tank 7 is a double-layer egg-shaped structure, and the middle interlayer of the anaerobic fermentation tank 7 is filled with heating and heat preservation water.

As shown in FIG. 3 , the cogeneration device 20 includes a gas turbine 12 , a generator 13 , a smoke exhauster 14 , a waste heat boiler 15 and a steam turbine generator 16 , the gas turbine rotating shaft is connected to the main shaft of the generator 13 , and the exhaust port of the gas turbine 12 is connected to the exhaust port The smoker 14 and the smoke exhauster 14 are connected to the waste heat boiler 15 , and the steam of the waste heat boiler 15 is sent to the steam turbine generator 16 through pipes.

Claims (3)

1. A sludge treatment system for a sewage treatment plant, characterized in that it comprises a sludge concentration tank (1), a solar collector (5), a heat exchanger (6), an anaerobic fermentation tank (7) ) and cogeneration device (20), the sludge thickening tank (1) is divided into A pool and B pool, A pool is connected to the plate and frame filter press (2), the sludge drying room (3) and the sewage in turn through pipelines. Sludge incinerator (4); Pool B is connected to anaerobic fermentation tank (7), biogas slurry and residue collector (18) and separator (19) in sequence through pipelines; part of the steam of sludge incinerator (4) passes through pipelines Transported to the heat exchanger (6), the low-temperature liquid of the heat exchanger (6) is in circulation with the interlayer of the anaerobic fermenter (7) and the pipeline of the solar heat collecting device (5) through the pipeline; the anaerobic fermenter (7) The gas outlet of the gas storage chamber (8), the biogas desulfurizer (9), the biogas purifier (10) and the methane compressor (11) are connected to the gas turbine (12) of the cogeneration device (20) through the pipeline in turn, and the sewage Another part of the steam from the mud incinerator (4) is piped to the steam turbine generator (16) of the cogeneration unit (20), which is electrically connected to the power output unit (17). 2. The sludge treatment system for a sewage treatment plant according to claim 1, characterized in that: the anaerobic fermentation tank (7) is a double-layer egg-shaped structure, and the middle interlayer of the anaerobic fermentation tank (7) Fill with heated insulation water. 3. The sludge treatment system for a sewage treatment plant according to claim 1 or 2, wherein the cogeneration device (20) comprises a gas turbine (12), a generator (13), a smoke exhauster (14) ), waste heat boiler (15) and steam turbine generator (16), the gas turbine rotating shaft is connected to the main shaft of the generator (13), the exhaust port of the gas turbine (12) is connected to the smoke exhauster (14), and the smoke exhauster (14) is connected to The waste heat boiler (15), the steam of the waste heat boiler (15) is sent to the steam turbine generator (16) through the pipeline.

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