An efficient utilization structure and method for a coal-fired unit coupled with sludge power generation

Abstract

The invention discloses an efficient utilization structure and method for coupling sludge power generation in a coal-fired unit, which includes a sludge treatment system (A), an exhaust gas transportation system (B), and an exhaust gas heat utilization system (C); the exhaust gas heat utilization system (C) is successively connected by pipelines from a first cyclone dust collector (6), a hot air cooler (7), a hot air circulation fan (8), a primary exhaust gas condenser (9), and a hot air reheater (5). It overcomes the disadvantages in the prior art that the potential of waste heat utilization, energy conservation, and consumption reduction is not exploited, the sludge drying system consumes a large amount of heat energy, and the operation cost is relatively high. The advantages are that the sludge dried by a disk dryer and a belt dryer has a certain low calorific value, and the dried sludge can be co-fired in a coal-fired boiler without adding auxiliary fuel to maintain the normal combustion of the incinerator, saving the coal consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy cleaning, and more specifically, to an efficient utilization structure and method for coupling sludge power generation with a coal-fired unit. Background Art

[0002] The moisture content of the sludge dehydrated by a municipal sewage treatment plant is 60%-80%. It not only contains a large amount of organic matter, but also contains more harmful substances such as pathogenic microorganisms and heavy metals, and is accompanied by a foul smell. If it is not harmlessly disposed of, it is easy to cause secondary pollution to the environment.

[0003] Currently, the disposal of sludge mostly adopts methods such as landfill, incineration, composting, and resource utilization, and incineration is a relatively effective way to solve the reduction and harmless treatment of sludge.

[0004] If the direct incineration technology is adopted for sludge, an incinerator and a supporting flue gas purification and treatment system need to be built, with a large initial investment in the project, high operating costs, and poor economy.

[0005] Relying on the advantages of the efficient power generation system and ultra-low pollutant emissions of the existing coal-fired units, using various heat sources such as power plant steam and flue gas, after the sludge is dried, it is coupled for incineration treatment. The sludge will be reduced by more than 95%. The harmful substances are completely decomposed by high-temperature incineration above 900°C in the boiler. It can not only save land resources for landfill, effectively control secondary pollution, but also be comprehensively utilized, recover the heat of the sludge for power generation of the coal-fired unit, and be transformed into clean energy, achieving the purpose of developing new energy and implementing circular economy.

[0006] Sludge drying can be divided into direct drying (such as flue gas) and indirect drying (such as steam) according to different drying media. The main types of dryers on the market are disk type, paddle type, belt drying, fluidized bed, rotary drum type, etc.

[0007] Currently, in the traditional coal-fired power plant sludge drying and incineration scheme, mostly the disk type steam drying process is adopted to dry the sludge with a single moisture content (such as 80% or 60%) to 35%-40%, without tapping the potential of waste heat utilization and energy conservation and consumption reduction. The sludge drying system consumes a large amount of heat energy and has relatively high operating costs.

[0008] Therefore, there is an urgent need for a device that can fully tap and utilize the waste heat of the sludge and a system with low overall operating costs. Summary of the Invention

[0009] The first object of the present invention is to overcome the deficiencies of the above background art and propose an efficient utilization structure for coupling sludge power generation with a coal-fired unit.

[0010] The first object of the present invention is implemented through the following technical solutions: An efficient utilization structure for a coal-fired unit coupled with sludge power generation, which includes a sludge treatment system, an exhaust gas conveying system, and an exhaust gas heat utilization system.

[0011] The heat outlet end of the sludge treatment system is communicated with the inlet section of the exhaust gas heat utilization system, and the gas outlet end of the sludge treatment system is communicated with the inlet end of the exhaust gas conveying system.

[0012] The exhaust gas heat utilization system is sequentially connected by a first cyclone dust collector, a hot air cooler, a hot air circulation fan, a primary exhaust gas condenser, and a hot air reheater through pipelines.

[0013] In the above technical solution: The sludge treatment system includes two wet sludge treatment pipelines.

[0014] The first wet sludge pipeline is sequentially connected in series by the first wet sludge bin, a wet sludge scraper conveyor, and a belt dryer through pipelines.

[0015] The second wet sludge pipeline is sequentially connected in series by the second wet sludge bin, a screw pump, and a disk dryer through pipelines.

[0016] Two pipelines are led out from the belt dryer. One pipeline is connected to the first dry sludge scraper conveyor through a first cyclone dust collector by a pipeline, and the other pipeline is directly connected to the first dry sludge scraper conveyor.

[0017] Two pipelines are led out from the disk dryer. One pipeline is connected to the first dry sludge scraper conveyor through a second cyclone dust collector by a pipeline, and the other pipeline is directly connected to the first dry sludge scraper conveyor.

[0018] The first dry sludge scraper conveyor is sequentially connected to a dry sludge bin and a second dry sludge scraper conveyor through pipelines, and the second dry sludge scraper conveyor is connected to an external boiler through a coal conveying belt.

[0019] In the above technical solution: A first screw feeder is provided at the bottom of the first wet sludge bin, a second screw feeder is provided at the bottom of the second wet sludge bin, and a third screw feeder is provided at the bottom of the dry sludge bin.

[0020] In the above technical solution: The disk dryer is connected to the auxiliary steam of an external power plant through a pipeline, and the condensate water in the disk dryer is communicated with the outside through a pipeline.

[0021] In the above technical solution: The exhaust gas conveying system is sequentially connected by a primary exhaust gas condenser, a secondary exhaust gas condenser, an exhaust gas induced draft fan, and a boiler air supply system through pipelines.

[0022] The front end of the primary exhaust gas condenser is connected to the disk dryer through a second cyclone dust collector.

[0023] The bottoms of the primary exhaust gas condenser and the secondary exhaust gas condenser are connected to the condensate wastewater treatment system through pipelines.

[0024] In the above technical solution: The hot air reheater is connected to the belt dryer through a pipeline.

[0025] The second object of the present invention is to propose an efficient utilization method for a coal-fired power unit coupled with sludge power generation.

[0026] The second object of the present invention is implemented through the following technical solution: An efficient utilization method for a coal-fired power unit coupled with sludge power generation, which includes the following steps;

[0027] ①. The wet sludge with low moisture content enters the first wet sludge bin. A first screw feeder is arranged at the bottom of the first wet sludge bin. The first screw feeder operates and spirally flips the wet sludge in the first wet sludge bin. The flipped wet sludge is conveyed by the wet sludge scraper under the traction of the scraper chain, and then enters the belt dryer for drying the wet sludge.

[0028] ②. At the same time as step ①, the wet sludge with high moisture content enters the second wet sludge bin. A second screw feeder is arranged at the bottom of the second wet sludge bin. The second screw feeder spirally flips the wet sludge with high moisture content inside. The flipped wet sludge is pumped through a screw pump and extruded from one sealed cavity to another sealed cavity in a continuous rotation of the screw and a sludge spiral form, and finally conveyed into the disk dryer for indirect heating and drying.

[0029] ③. In steps ① and ②, the dried sludge enters the first dry sludge scraper along with the pipeline. The first dry sludge scraper conveys the dry sludge through the scraper, and then enters the dry sludge bin. A third screw feeder is arranged at the bottom of the dry sludge bin. The third screw feeder spirally flips the dried sludge in the dry sludge bin again. Then the dry sludge enters the second dry sludge scraper. The second dry sludge scraper sends the dried sludge to the coal conveying belt through the scraper. The coal conveying belt conveys the dry sludge to the boiler for incineration.

[0030] ④. When the disk dryer dries wet sludge with a high moisture content in step ②, a large amount of sludge off-gas is formed during the drying process of the wet sludge with a high moisture content. The sludge off-gas enters the second cyclone dust collector through a pipeline for dust removal treatment. The sludge off-gas after dust removal treatment passes through a pipeline and is sequentially cooled by a primary off-gas condenser and a secondary off-gas condenser. The cooled sludge off-gas is sent to the boiler air supply system by an exhaust gas induced draft fan, and the sludge off-gas is incinerated in the boiler after being mixed in the boiler air supply system;

[0031] ⑤. The wet sludge with a low moisture content dried by the belt dryer in step ①, and the sludge off-gas formed during the drying process of the wet sludge with a low moisture content. The sludge off-gas enters the first cyclone dust collector through a pipeline for dust removal treatment. After dust removal, the sludge off-gas enters the hot air cooler through a pipeline for temperature reduction and water recovery, and then enters the hot air circulation fan through a pipeline to boost the pressure. The sludge off-gas after pressure boosting enters the primary off-gas condenser for waste heat recovery;

[0032] ⑥. While treating the sludge off-gas in the belt dryer in step ⑤, the sludge off-gas generated in the disk dryer. Here, the temperature of the sludge off-gas is higher than the temperature of the sludge off-gas entering the primary off-gas condenser in step ⑤. The high-temperature sludge off-gas in the disk dryer exchanges heat indirectly with the sludge off-gas in step ⑤ in the primary off-gas condenser;

[0033] ⑦. After the sludge off-gas that undergoes heat exchange in steps ⑤ and ⑥ recovers waste heat in the primary off-gas condenser, the sludge off-gas enters the hot air reheater through a pipeline for further temperature increase. The heated sludge off-gas enters the belt dryer for recycling in drying the wet sludge, and the sludge off-gas maintains self-circulation throughout the process.

[0034] In the above technical solution: The difference in moisture content between the wet sludge with a high moisture content and the wet sludge with a low moisture content is 20%-30%; the moisture content of the wet sludge with a high moisture content is between 75%-85%, and the moisture content of the wet sludge with a low moisture content is between 55%-65%.

[0035] In the above technical solution: In step ⑦, one side pipeline of the hot air reheater is connected to the external power plant auxiliary steam pipeline, and the other side is provided with a condensate pipeline.

[0036] In the above technical solution: In step ④; the condensate formed after the sludge off-gas is condensed in the primary off-gas condenser and the secondary off-gas condenser is connected to the condensate wastewater treatment system through a pipeline and discharged up to standard after treatment.

[0037] The present invention has the following advantages: 1. Compared with the conventional sludge drying system, the utilization of waste heat is not considered. In the present invention, a disk dryer in the waste gas heat utilization system generates a large amount of waste gas heat through indirect heat exchange of disks when treating high-moisture-content wet sludge. A large amount of waste gas heat is exchanged with the sludge waste gas transported by the hot air circulation fan in the primary waste gas condenser through the second cyclone dust collector, and the large amount of waste heat generated by the disk dryer when treating high-moisture-content wet sludge is fully utilized;

[0038] At the same time, compared with the conventional sludge drying system (without considering waste heat utilization, more steam is required), the steam consumption can be saved by about 3.2 t / h, the steam consumption per ton of sludge is reduced, and thus energy conservation and consumption reduction in sludge disposal are achieved.

[0039] 2. The sludge dried by the disk dryer and the belt dryer in the present invention has a certain lower calorific value. When co-firing the dried sludge in a coal-fired boiler, no auxiliary fuel needs to be added to maintain the normal combustion of the incinerator, and the coal consumption is saved.

[0040] After a large amount of calculations: If the plan of treating 300 tons of sludge with 80% water content per day and 200 tons of sludge with 60% water content per day is considered, after co-firing sludge and coal for power generation, the standard coal saved by the two boilers under the BMCR condition is 6078 t / a. Calculated at a standard coal price of 730 yuan / t, the cost saved is about 4.436 million yuan. Brief Description of the Drawings

[0041] Figure 1 It is a schematic structural diagram of the present invention.

[0042] In the figure: sludge treatment system A, waste gas transportation system B, waste gas heat utilization system C, first wet sludge bin 1, first screw feeder 2, wet sludge scraper 3, belt dryer 4, hot air reheater 5, first cyclone dust collector 6, hot air cooler 7, hot air circulation fan 8, primary waste gas condenser 9, secondary waste gas condenser 10, exhaust gas induced draft fan 11, boiler air supply system 12, condensate wastewater treatment system 13, second wet sludge bin 14, second screw feeder 15, screw pump 16, disk dryer 17, first dry sludge scraper 18, dry sludge bin 19, third screw feeder 20, second dry sludge scraper 21, coal conveying belt 22, second cyclone dust collector 23, boiler 24.

[0043] In the figure, Q represents the auxiliary steam of the power plant, and S represents the condensate water. Detailed Embodiments

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0045] Reference Figure 1 As shown: An efficient utilization structure for a coal-fired unit coupled with sludge power generation, which includes a sludge treatment system A, an exhaust gas conveying system B, and an exhaust gas heat utilization system C;

[0046] During the sludge treatment process of the sludge treatment system A, a large amount of heat and gas are generated. A large amount of heat enters the exhaust gas heat utilization system C for heat exchange, and the generated gas enters the exhaust gas conveying system B for incineration. The exhaust gas heat utilization system C is sequentially connected by a first cyclone dust collector 6, a hot air cooler 7, a hot air circulation fan 8, a primary exhaust gas condenser 9, and a hot air reheater 5 through pipelines.

[0047] The sludge treatment system A includes two wet sludge treatment pipelines;

[0048] The first wet sludge pipeline is sequentially connected in series by the first wet sludge bin 1, a wet sludge scraper 3, and a belt dryer 4 through pipelines;

[0049] The second wet sludge pipeline is sequentially connected in series by the second wet sludge bin 14, a screw pump 16, and a disk dryer 17 through pipelines;

[0050] Two pipelines are led out from the belt dryer 4. One pipeline is connected to the first dry sludge scraper 18 through the first cyclone dust collector 6 by a pipeline, and the other pipeline is directly connected to the first dry sludge scraper 18;

[0051] Two pipelines are led out from the disk dryer 17. One pipeline is connected to the first dry sludge scraper 18 through the second cyclone dust collector 23 by a pipeline, and the other pipeline is directly connected to the first dry sludge scraper 18;

[0052] The first dry sludge scraper 18 is sequentially connected to a dry sludge bin 19 and a second dry sludge scraper 21 through pipelines. The second dry sludge scraper 21 is connected to an external boiler 24 through a coal conveying belt 22.

[0053] The sludge treatment system A includes two wet sludge treatment pipelines, that is, wet sludge with a low moisture content treated by a belt dryer and wet sludge with a high moisture content treated by a disk dryer;

[0054] The sludge treatment system A can simultaneously treat two kinds of wet sludge with different moisture contents, dry the wet sludge with different moisture contents respectively, so as to be more flexible in the adaptive treatment of wet sludge.

[0055] A first screw feeder 2 is arranged at the bottom of the first wet sludge bin 1, a second screw feeder 15 is arranged at the bottom of the second wet sludge bin 14, and a third screw feeder 20 is arranged at the bottom of the dry sludge bin 19.

[0056] The first wet sludge silo 1, the second wet sludge silo 14, and the dry sludge silo 19 are respectively provided with a first screw feeder 2, a second screw feeder 15, and a third screw feeder 20 at the bottom, which can effectively solve the problem of easy blockage of the sludge silo.

[0057] The disc dryer 17 is connected to the auxiliary steam of the external power plant through a pipeline, and the condensate water in the disc dryer 17 is connected to the outside through a pipeline. The auxiliary steam in the power plant is used for indirect heat exchange in the disc dryer to realize the drying of wet sludge with high moisture content; at the same time, a pipeline is provided on one side of the disc dryer 17, and the condensate water formed when the wet sludge with high moisture content is dried in the disc dryer 17 is discharged from one side through the pipeline.

[0058] The exhaust gas conveying system B is composed of a primary exhaust gas condenser 9, a secondary exhaust gas condenser 10, an exhaust gas induced draft fan 11, and a boiler air supply system 12 connected in sequence through pipelines.

[0059] The front end of the primary exhaust gas condenser 9 is connected to the disc dryer 17 through a second cyclone dust collector 23.

[0060] The bottoms of the primary exhaust gas condenser 9 and the secondary exhaust gas condenser 10 are connected to the condensate wastewater treatment system 13 through pipelines.

[0061] The exhaust gas conveying system B can realize the separation of gas phase, liquid phase, and solid phase in the exhaust gas. The waste gas in the gas phase enters the boiler air supply system and is co-incinerated in the boiler without external discharge.

[0062] The liquid phase is condensed into waste liquid through the exhaust gas condenser and then enters the condensate wastewater treatment system for recovery and utilization, and the liquid is not discharged externally.

[0063] The dust-containing sludge in the solid phase enters the dry sludge conveying system and is finally sent to the boiler for incineration. The waste gas and waste liquid are not discharged externally during the whole process, and zero discharge can be achieved.

[0064] The hot air reheater 5 is connected to the belt dryer 4 through a pipeline. This structure can realize the hot air self-circulation of the exhaust gas generated by the belt dryer and supplement heat according to needs, so as to realize the gradient recovery and utilization of waste heat.

[0065] The present invention also includes a method: a high-efficiency utilization method for coupling sludge power generation in a coal-fired unit, which includes the following steps;

[0066] ①. The wet sludge with low moisture content enters the first wet sludge bin 1. A first screw feeder 2 is arranged at the bottom of the first wet sludge bin 1. The first screw feeder 2 operates to helically turn over the wet sludge in the first wet sludge bin 1. The turned-over wet sludge is conveyed by the wet sludge scraper conveyor 3 under the traction of the scraper chain, and then enters the belt dryer 4 for drying the wet sludge.

[0067] The belt dryer 4 is mainly composed of a number of conveyor belts. While the sludge is being conveyed by the conveyor belt, it contacts the self-circulating exhausted gas with heat for heat exchange and drying. (The self-circulating exhausted gas with heat is mainly the exhausted gas with heat generated when the belt dryer 4 dries the wet sludge with low moisture content. This part of the exhausted gas with heat exchanges heat with the wet sludge with low moisture content in the belt dryer 4 for drying.)

[0068] At the same time, the hot gas passes through the material laid on the mesh belt from bottom to top or from top to bottom, heating and drying it and taking away the moisture.

[0069] ②. At the same time as step ①, the wet sludge with high moisture content enters the second wet sludge bin 14. A second screw feeder 15 is arranged at the bottom of the second wet sludge bin 14. The second screw feeder 15 helically turns over the wet sludge with high moisture content inside. The turned-over wet sludge is sent to the disc dryer 17 through the screw pump 16 by continuous rotation of the screw and the sludge spiral form, being pressed from one sealed cavity to another sealed cavity and extruded out of the pump body, and finally transported for indirect heating and drying.

[0070] ③. The dried sludge after drying in steps ① and ② enters the first dry sludge scraper conveyor 18 along the pipeline. The first dry sludge scraper conveyor 18 conveys the dry sludge through the scraper, and then enters the dry sludge bin 19. A third screw feeder 20 is arranged at the bottom of the dry sludge bin 19. The third screw feeder 20 helically turns over the dried sludge in the dry sludge bin 19 again. Then the dry sludge enters the second dry sludge scraper conveyor 21. The second dry sludge scraper conveyor 21 sends the dried sludge to the coal-fired conveyor belt 22 through the scraper. The coal-fired conveyor belt 22 transports the dry sludge to the boiler 24 for incineration.

[0071] ④. When the disc dryer 17 dries the wet sludge with high moisture content in step ②, a large amount of sludge exhausted gas is formed during the drying process of the wet sludge with high moisture content. The sludge exhausted gas enters the second cyclone dust collector 23 through the pipeline for dust removal treatment. The sludge exhausted gas after dust removal treatment passes through the primary exhausted gas condenser 9 and the secondary exhausted gas condenser 10 in sequence through the pipeline for temperature reduction treatment. The sludge exhausted gas after temperature reduction treatment is sent to the boiler air supply system 12 by the exhaust gas induced draft fan 11, and the sludge exhausted gas is incinerated and treated in the boiler after being mixed in the boiler air supply system 12.

[0072] ⑤. In step ①, the wet sludge with low water content dried by the belt dryer 4, and the sludge exhaust gas formed during the drying process of the wet sludge with low water content. The sludge exhaust gas enters the first cyclone dust collector 6 through a pipeline for dust removal treatment. After dust removal, the sludge exhaust gas enters the hot air cooler 7 through a pipeline for temperature reduction and water recovery, and then enters the hot air circulation fan 8 through a pipeline to boost the pressure. The pressurized sludge exhaust gas enters the primary exhaust gas condenser 9 for waste heat recovery;

[0073] ⑥. While treating the sludge exhaust gas in the belt dryer 4 in step ⑤, the sludge exhaust gas generated in the disk dryer 17. Here, the temperature of the sludge exhaust gas is higher than that of the sludge exhaust gas entering the primary exhaust gas condenser 9 in step ⑤. The high-temperature sludge exhaust gas of the disk dryer 17 exchanges heat indirectly with the sludge exhaust gas in step ⑤ in the primary exhaust gas condenser 9;

[0074] ⑦. After the sludge exhaust gas that undergoes heat exchange in steps ⑤ and ⑥ recovers waste heat in the primary exhaust gas condenser 9, the sludge exhaust gas enters the hot air reheater 5 through a pipeline for further temperature increase. The heated sludge exhaust gas enters the belt dryer 4 for recycling in drying the wet sludge. During the whole process, the sludge exhaust gas maintains self-circulation.

[0075] The difference in water content between the wet sludge with high water content and the wet sludge with low water content is 20% - 30%; the water content of the wet sludge with high water content is between 75% - 85%, and the water content of the wet sludge with low water content is between 55% - 65%. By utilizing the drying requirements and characteristics of sludge with different water contents, the waste heat of the dried sludge exhaust gas can be recycled in a gradient manner, thus achieving energy conservation and consumption reduction.

[0076] In step ⑦, one side pipeline of the hot air reheater 5 is connected to the external auxiliary steam pipeline of the power plant, and the other side is provided with a condensate pipeline.

[0077] In step ④; the condensate formed after the sludge exhaust gas is condensed in the primary exhaust gas condenser 9 and the secondary exhaust gas condenser 10 is connected to the condensate wastewater treatment system 13 through a pipeline for treatment and then discharged up to standard. The condensate wastewater treatment system 13 recovers and treats the condensate of the sludge exhaust gas, and zero wastewater discharge can be achieved.

[0078] In the present invention, a large amount of exhaust gas heat is generated through indirect heat exchange of the disks when the disk dryer in the exhaust gas heat utilization system treats the wet sludge with high water content. A large amount of exhaust gas heat exchanges heat with the sludge exhaust gas transported by the hot air circulation fan in the primary exhaust gas condenser through the second cyclone dust collector, and the large amount of waste heat generated when the disk dryer treats the wet sludge with high water content is fully utilized;

[0079] Compared with the conventional sludge drying system that utilizes waste heat simultaneously (without considering waste heat utilization, more steam is required), the steam consumption can be saved by approximately 3.2 t / h, reducing the steam consumption per ton of sludge, thereby achieving energy conservation and consumption reduction in sludge disposal.

[0080] The sludge dried by the disk dryer and the belt dryer in the present invention has a certain low calorific value. When the dried sludge is co-fired in a coal-fired boiler, the normal combustion of the incinerator can be maintained without adding auxiliary fuel, saving coal consumption.

[0081] After a large number of calculations: If the daily treatment of 300 tons of sludge with 80% water content and 200 tons of sludge with 60% water content is considered, after coal-fired coupled sludge power generation, the standard coal savings of the two boilers under the BMCR condition is 6078 t / a. Calculated at a standard coal price of 730 yuan / t, the cost savings is approximately 4.436 million yuan. 。 The parts not described in detail above are all prior arts.

Claims

1. An efficient utilization structure for a coal-fired unit coupled with sludge power generation, Characterized in that: It includes a sludge treatment system (A), an exhaust gas conveying system (B) and an exhaust gas heat utilization system (C), The heat outlet end of the sludge treatment system (A) is connected to the inlet section of the exhaust gas heat utilization system (C), the gas outlet end of the sludge treatment system (A) is connected to the inlet end of the exhaust gas conveying system (B), and the exhaust gas heat utilization system (C) is successively connected by pipelines from a first cyclone dust collector (6), a hot air cooler (7), a hot air circulation fan (8), a primary exhaust gas condenser (9) and a hot air reheater (5); The sludge treatment system (A) includes two wet sludge treatment pipelines; The first wet sludge pipeline is successively connected in series by a first wet sludge bin (1), a wet sludge scraper conveyor (3) and a belt dryer (4) through pipelines; The second wet sludge pipeline is successively connected in series by a second wet sludge bin (14), a screw pump (16) and a disk dryer (17) through pipelines; Two pipelines are led out from the belt dryer (4), one is connected to the first dry sludge scraper conveyor (18) through a first cyclone dust collector (6) by a pipeline, and the other is directly connected to the first dry sludge scraper conveyor (18); Two pipelines are led out from the disk dryer (17), one is connected to the first dry sludge scraper conveyor (18) through a second cyclone dust collector (23) by a pipeline, and the other is directly connected to the first dry sludge scraper conveyor (18); The front end of the primary exhaust gas condenser (9) is connected to the disk dryer (17) through a second cyclone dust collector (23), The first dry sludge scraper conveyor (18) is successively connected to a dry sludge bin (19) and a second dry sludge scraper conveyor (21) through pipelines, and the second dry sludge scraper conveyor (21) is connected to an external boiler (24) through a coal conveying belt (22); The hot air reheater (5) is connected to the belt dryer (4) through a pipeline.

2. The efficient utilization structure for a coal-fired unit coupled with sludge power generation according to claim 1, Characterized in that: A first screw feeder (2) is arranged at the bottom of the first wet sludge bin (1), a second screw feeder (15) is arranged at the bottom of the second wet sludge bin (14), and a third screw feeder (20) is arranged at the bottom of the dry sludge bin (19).

3. The efficient utilization structure for a coal-fired unit coupled with sludge power generation according to claim 1, Characterized in that: The disk dryer (17) is connected to the auxiliary steam of an external power plant through a pipeline, and the condensate water in the disk dryer (17) communicates with the outside through a pipeline.

4. The efficient utilization structure for a coal-fired unit coupled with sludge power generation according to claim 1, Characterized in that: The exhaust gas conveying system (B) is successively connected by pipelines from a primary exhaust gas condenser (9), a secondary exhaust gas condenser (10), an exhaust gas induced draft fan (11) and a boiler air supply system (12), The bottom of the primary exhaust condenser (9) and the secondary exhaust condenser (10) is connected to the condensate wastewater treatment system (13) through a pipeline.

5. A method for the efficient utilization structure of a coal-fired unit coupled with sludge power generation according to any one of claims 1-4, characterized in that: it comprises the following steps; ①. The wet sludge with low moisture content enters the first wet sludge bin (1). A first screw feeder (2) is arranged at the bottom of the first wet sludge bin (1). The first screw feeder (2) operates to helically turn the wet sludge in the first wet sludge bin (1). The turned wet sludge is conveyed by a wet sludge scraper conveyor (3) under the traction of a scraper chain, and then enters a belt dryer (4) for drying the wet sludge. ②. At the same time as step ①, the wet sludge with high moisture content enters the second wet sludge bin (14). A second screw feeder (15) is arranged at the bottom of the second wet sludge bin (14). The second screw feeder (15) helically turns the wet sludge with high moisture content inside. The turned wet sludge is extruded from one sealing cavity to another sealing cavity and out of the pump body through the continuous rotation of the screw and the sludge spiral form by a screw pump (16), and finally conveyed into a disk dryer (17) for indirect heating and drying. ③. In steps ① and ②, the dried sludge enters the first dry sludge scraper conveyor (18) along the pipeline. The first dry sludge scraper conveyor (18) conveys the dry sludge through a scraper, and then enters a dry sludge bin (19). A third screw feeder (20) is arranged at the bottom of the dry sludge bin (19). The third screw feeder (20) helically turns the dried sludge in the dry sludge bin (19) again. Then the dry sludge enters a second dry sludge scraper conveyor (21). The second dry sludge scraper conveyor (21) sends the dried sludge to a coal conveying belt (22) through a scraper. The coal conveying belt (22) conveys the dry sludge into a boiler (24) for incineration. ④. When the disk dryer (17) dries the wet sludge with high moisture content in step ②, a large amount of sludge exhaust gas is formed during the drying process of the wet sludge with high moisture content. The sludge exhaust gas enters a second cyclone dust collector (23) through a pipeline for dust removal treatment. The sludge exhaust gas after dust removal treatment passes through a primary exhaust condenser (9) and a secondary exhaust condenser (10) in sequence through a pipeline for temperature reduction treatment. The sludge exhaust gas after temperature reduction treatment is sent to a boiler air supply system (12) by an exhaust gas induced draft fan (11), and the sludge exhaust gas is incinerated in the boiler after being mixed in the boiler air supply system (12). ⑤. In step ①, the wet sludge with low moisture content dried by the belt dryer (4), and the sludge exhausted gas formed during the drying process of the wet sludge with low moisture content. The sludge exhausted gas enters the first cyclone dust collector (6) through a pipeline for dust removal treatment. After dust removal, the sludge exhausted gas enters the hot air cooler (7) through a pipeline for temperature reduction and water recovery, and then enters the hot air circulation fan (8) through a pipeline for pressure boosting. The sludge exhausted gas after pressure boosting enters the primary exhausted gas condenser (9) for waste heat recovery; ⑥. While treating the sludge exhausted gas in the belt dryer (4) in step ⑤, the sludge exhausted gas generated in the disk dryer (17). Here, the temperature of the sludge exhausted gas is higher than that of the sludge exhausted gas entering the primary exhausted gas condenser (9) in step ⑤. The high-temperature sludge exhausted gas from the disk dryer (17) exchanges heat indirectly with the sludge exhausted gas in step ⑤ in the primary exhausted gas condenser (9); ⑦. After the sludge exhausted gas that undergoes heat exchange in steps ⑤ and ⑥ recovers waste heat in the primary exhausted gas condenser (9), the sludge exhausted gas enters the hot air reheater (5) through a pipeline for further temperature increase. The sludge exhausted gas after temperature increase enters the belt dryer (4) for recycling in drying the wet sludge. During the whole process, the sludge exhausted gas maintains self-circulation.

6. The method for an efficient utilization structure of a coal-fired unit coupled with sludge power generation according to claim 5, characterized in that: The difference in moisture content between the wet sludge with high moisture content and the wet sludge with low moisture content is 20% - 30%; the moisture content of the wet sludge with high moisture content is between 75% - 85%, and the moisture content of the wet sludge with low moisture content is between 55% - 65%.

7. The method for an efficient utilization structure of a coal-fired unit coupled with sludge power generation according to claim 6, characterized in that: In step ⑦, one side pipeline of the hot air reheater (5) is connected to the external auxiliary steam pipeline of the power plant, and the other side is provided with a condensate pipeline.

8. The method for an efficient utilization structure of a coal-fired unit coupled with sludge power generation according to claim 7, characterized in that: In step ④; The condensate formed after the sludge exhausted gas is condensed in the primary exhausted gas condenser (9) and the secondary exhausted gas condenser (10) is connected to the condensate wastewater treatment system (13) through a pipeline for treatment and then discharged up to standard.

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