Thermal power unit coupled with solid waste treatment system

Abstract

The present application relates to solid waste treatment technical field and disclose a kind of solid waste treatment system coupled to thermal power generating unit, including thermal power generating unit, drying box, fused salt heat storage system and coal mill, thermal power generating unit includes boiler and steam turbine, drying box is equipped with first heating module, second heating module and third heating module that are sequentially connected in series, solid waste is sequentially dried by each heating module, first heating module is connected with the steam extraction line of steam turbine, fused salt heat storage system is connected with steam turbine, to absorb and buffer the excess heat of steam turbine, and fused salt heat storage system is connected with second heating module and third heating module, for providing heat to second heating module and third heating module, coal mill is connected with third heating module and boiler, to dry solid waste is transported to the boiler and is mixed and burned.The present application embodiment utilizes multistage drying to cooperate fused salt heat storage system, can make full use of the waste heat of thermal power generating unit, and can realize the buffering and cascade utilization of waste heat, improves the efficiency of solid waste treatment.

Description

Technical Field

[0001] This invention belongs to the field of solid waste treatment technology, specifically relating to a thermal power unit coupled solid waste treatment system. Background Technology

[0002] The use of waste heat from thermal power units for sludge drying is already common in related technologies. However, with the increasing proportion of new energy sources and grid fluctuations, the operating conditions of thermal power units are frequently adjusted, and the supply of surplus heat is unstable. Existing sludge heating systems lack flexible energy buffering and cascade utilization mechanisms, making it difficult to adapt to fluctuations in operating conditions. In addition, traditional heating media have problems such as low heat storage density and narrow temperature regulation range, resulting in poor continuity of sludge treatment and high energy consumption. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a thermal power unit coupled with a solid waste treatment system. This system utilizes a multi-stage drying system combined with a molten salt thermal storage system to fully utilize the waste heat of the thermal power unit, and enables heat buffering and tiered utilization, thereby improving the continuity of solid waste treatment and reducing energy consumption.

[0004] The thermal power unit coupled solid waste treatment system of this invention includes a thermal power unit, a drying chamber, a molten salt thermal storage system, and a coal mill. The thermal power unit includes a boiler and a steam turbine. The drying chamber is equipped with a first heating module, a second heating module, and a third heating module arranged in series. The first heating module is used to introduce solid waste, which is then dried sequentially through each heating module. The first heating module is connected to the steam extraction pipeline of the steam turbine to utilize the waste heat of the steam in the extraction pipeline for preliminary drying of the solid waste. The molten salt thermal storage system is connected to the steam turbine to absorb and buffer the excess heat of the steam turbine. The molten salt thermal storage system is also connected to the second and third heating modules to provide heat to them. The inlet of the coal mill is connected to the outlet of the third heating module, and the outlet of the coal mill is connected to the coal feed port of the boiler to transport the solid waste dried by the third heating module to the boiler for co-firing.

[0005] The solid waste treatment system coupled with thermal power units in this invention utilizes the waste heat from the steam extraction pipeline of the steam turbine to perform preliminary drying of solid waste, achieving effective recovery of low-grade waste heat. Simultaneously, the system introduces a molten salt thermal storage system to absorb and buffer excess heat from the steam turbine, providing a stable, high-grade heat source for the subsequent drying stage, thus solving the problem of traditional single waste heat supply being greatly affected by unit load fluctuations. Finally, the deeply dried solid waste is ground and fed into the boiler for co-firing, realizing the resource utilization of solid waste and improving overall energy efficiency.

[0006] In some embodiments, the thermal power unit coupled solid waste treatment system further includes a pretreatment unit, which includes a steam-water heat exchanger and a dissolving tank. The steam side of the steam-water heat exchanger is connected to the exhaust pipe of the low-pressure cylinder of the steam turbine. The water side of the steam-water heat exchanger is used to introduce a dechlorination solution. The inlet of the dissolving tank is used to introduce the solid waste and is connected to the water side outlet of the steam-water heat exchanger to receive the heated dechlorination solution and wash and dechlorinate the solid waste. The outlet of the dissolving tank is connected to the feed inlet of the first heating module.

[0007] In some embodiments, the first heating module, the second heating module, and the third heating module are each provided with a heat source input terminal and a heat source output terminal, for supplying steam generated by the steam turbine or molten salt in the molten salt thermal storage system to enter and flow out.

[0008] In some embodiments, the molten salt thermal storage system includes: a first molten salt tank, a second molten salt tank, a molten salt-steam heat exchanger, and a first circulation pipeline. The steam side of the molten salt-steam heat exchanger is connected to the exhaust pipe of the intermediate-pressure cylinder of the steam turbine. The first circulation pipeline is sequentially connected to the outlet of the first molten salt tank, the heat source input terminal of the third heating module, the heat source output terminal of the third heating module, the inlet of the second molten salt tank, the outlet of the second molten salt tank, the molten salt side of the molten salt-steam heat exchanger, and the inlet of the first molten salt tank, so that the molten salt in the first circulation pipeline absorbs and buffers the waste heat of the exhaust pipe of the intermediate-pressure cylinder of the steam turbine and releases it to the third heating module.

[0009] In some embodiments, the molten salt thermal storage system further includes a molten salt-molten salt heat exchanger and a second circulation pipeline. The molten salt-molten salt heat exchanger has a heat source molten salt side and a cold source molten salt side. The second circulation pipeline connects the cold source molten salt side of the molten salt-molten salt heat exchanger, the heat source input terminal and the heat source output terminal of the second heating module. The heat source molten salt side is located between the heat source output terminal of the third heating module and the liquid inlet of the second molten salt storage tank, so that the molten salt in the first circulation pipeline heats the molten salt in the second circulation pipeline.

[0010] In some embodiments, the first circulation line and the second circulation line are provided with at least one of a pump, a shut-off valve, and a regulating valve.

[0011] In some embodiments, the thermal power unit coupled solid waste treatment system further includes a steam return pipeline. One end of the steam return pipeline is connected to the exhaust pipeline of the low-pressure cylinder of the steam turbine, and the other end of the steam return pipeline is connected to the boiler. The steam return pipeline is used to supply steam into the boiler to condition the solid waste entering the boiler. The extraction pipeline of the low-pressure cylinder of the steam turbine is connected to the heat source input end of the first heating module, and the heat source output end of the first heating module is connected to the steam return pipeline.

[0012] In some embodiments, a heater is provided on the steam return line.

[0013] In some embodiments, a deaerator is provided on the steam return line.

[0014] In some embodiments, the operating temperature range of the first heating module is 120-150℃.

[0015] In some embodiments, the operating temperature range of the second heating module is 200-250℃.

[0016] In some embodiments, the operating temperature range of the third heating module is 300-350℃.

[0017] In some embodiments, the coal mill further includes a flue gas inlet, which is connected to the tail flue of the boiler via a flue gas duct.

[0018] This invention's embodiment of a thermal power unit coupled with a solid waste treatment system constructs a multi-stage drying, multi-heat-source, and thermal storage coupled solid waste treatment system. First, a pretreatment unit utilizes waste heat from turbine exhaust to heat a dechlorination solution, washing and dechlorinating the solid waste, thus reducing the risk of chlorine corrosion to the boiler at the source. Second, a tiered heating and drying process is formed by using waste heat from turbine extraction, molten salt thermal storage, and boiler tail gas, precisely matching the heat output to the solid waste dehydration and pyrolysis requirements, avoiding energy waste and localized overheating. The molten salt thermal storage system, as a key energy buffer unit, effectively mitigates heat fluctuations caused by peak shaving in the thermal power unit, ensuring the continuity and stability of the solid waste treatment process. The entire system achieves the harmless treatment of solid waste while improving the overall energy efficiency of the thermal power unit and reducing additional energy consumption and the risk of secondary pollution. Attached Figure Description

[0019] Figure 1 This is an overall schematic diagram of the thermal power unit coupled solid waste treatment system according to an embodiment of the present invention.

[0020] Figure label: 1. Thermal power unit; 11. Boiler; 12. Steam turbine; 121. High-pressure cylinder; 122. Intermediate-pressure cylinder; 123. Low-pressure cylinder; 13. Flue gas duct; 14. Reheater; 2. Drying oven; 21. First heating module; 22. Second heating module; 23. Third heating module; 3. Molten salt thermal storage system; 31. First molten salt storage tank; 32. Second molten salt storage tank; 33. Molten salt-steam heat exchanger; 34. First circulation pipeline; 35. Molten salt-molten salt heat exchanger; 36. Second circulation pipeline; 4. Coal mill; 5. Pretreatment unit; 51. Steam-water heat exchanger; 52. Dissolving tank; 6. Steam return line; 61. Heater; 62. Deaerator; 7. Pump; 8. Shut-off valve; 9. Control valve. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] like Figure 1 As shown, the solid waste treatment system coupled to the thermal power unit 1 in this embodiment of the invention includes a thermal power unit 1, a drying chamber 2, a molten salt thermal storage system 3, and a coal mill 4. The thermal power unit 1 includes a boiler 11 and a steam turbine 12. The drying chamber 2 is equipped with a first heating module 21, a second heating module 22, and a third heating module 23 arranged in series. The first heating module 21 is used to introduce solid waste, which is dried sequentially through each heating module. The first heating module 21 is connected to the extraction steam pipeline of the steam turbine 12 to utilize the steam in the extraction steam pipeline. The waste heat from the steam is used for preliminary drying of solid waste. The molten salt heat storage system 3 is connected to the steam turbine 12 to absorb and buffer the excess heat of the steam turbine 12. The molten salt heat storage system 3 is also connected to the second heating module 22 and the third heating module 23 to provide heat to them. The inlet of the coal mill 4 is connected to the outlet of the third heating module 23, and the outlet of the coal mill 4 is connected to the coal feed port of the boiler 11 to transport the solid waste dried by the third heating module 23 to the boiler 11 for co-firing.

[0023] The solid waste treatment system coupled with the thermal power unit 1 in this embodiment includes the thermal power unit 1, the drying box 2, the molten salt thermal storage system 3, and the coal mill 4.

[0024] The thermal power unit 1 includes a boiler 11, especially a CFB boiler 11, and a steam turbine 12, for generating electricity and producing high-temperature and high-pressure steam.

[0025] The drying chamber 2 is equipped with a first heating module 21, a second heating module 22, and a third heating module 23 arranged in series. The solid waste to be treated (such as sludge) first enters the first heating module 21, and then passes through the second heating module 22 and the third heating module 23 in sequence for gradient heating and drying.

[0026] The first heating module 21 is connected to the extraction steam pipeline of the steam turbine 12, specifically to the extraction steam pipeline of the low-pressure cylinder 123. The waste heat of the low-pressure steam (relatively low temperature) in the extraction steam pipeline is used to perform preliminary drying of solid waste, effectively recovering the low-grade waste heat of the steam turbine 12.

[0027] The molten salt thermal storage system 3 is connected to the steam turbine 12 to absorb and buffer excess heat generated by the steam turbine 12 under different loads. Simultaneously, the molten salt thermal storage system 3 is connected to the second heating module 22 and the third heating module 23 within the drying chamber 2, respectively, to provide these two modules with higher-grade heat to meet the high-temperature requirements for deep drying of solid waste.

[0028] The inlet of the coal mill 4 is connected to the outlet of the third heating module 23, and the outlet is connected to the coal feed port of the boiler 11. The solid waste, after being fully dried by the third heating module 23, is transported to the coal mill 4 for crushing and is finally fed into the boiler 11 to be mixed and co-fired with pulverized coal.

[0029] In practical application, firstly, the waste heat from the extraction steam pipeline of turbine 12 (generally the extraction steam pipeline of low-pressure cylinder 123) is directly utilized for preliminary drying, achieving on-site and low-cost recovery of the inherent waste heat of thermal power unit 1. Secondly, a molten salt thermal storage system 3 is introduced, solving the bottleneck problem of traditional single waste heat utilization methods being greatly affected by unit load fluctuations: when the unit load is high and there is surplus heat, the molten salt system can continuously heat up and undergo phase change to store heat. When stable heat is required for solid waste treatment, the molten salt system releases heat, thereby ensuring the continuity and stability of the drying process and eliminating the conflict between peak shaving and solid waste disposal of thermal power unit 1. Finally, through the tiered setting of three heating modules, the heat is matched from low to high to meet the different stages of solid waste dehydration requirements, avoiding the huge energy loss caused by directly treating high-moisture materials with high-temperature heat sources, and significantly improving overall energy efficiency.

[0030] In some embodiments, the thermal power unit 1 coupled solid waste treatment system further includes a pretreatment unit 5, which includes a steam-water heat exchanger 51 and a dissolving tank 52. The steam side of the steam-water heat exchanger 51 is connected to the exhaust pipe of the low-pressure cylinder 123 of the steam turbine 12. The water side of the steam-water heat exchanger 51 is used to introduce dechlorination solution. The inlet of the dissolving tank 52 is used to introduce solid waste and is connected to the water side outlet of the steam-water heat exchanger 51 to receive the heated dechlorination solution and wash and dechlorinate the solid waste. The outlet of the dissolving tank 52 is connected to the feed inlet of the first heating module 21.

[0031] In this embodiment, the steam side of the steam-water heat exchanger 51 is connected to the exhaust pipe of the low-pressure cylinder 123 of the steam turbine 12 to introduce low-temperature exhaust steam as a heat source.

[0032] In some specific embodiments, the exhaust pipe of the low-pressure cylinder 123 of the steam turbine 12 is divided into two parallel lines. One line is equipped with a condenser and connected to the steam return line 6, while the other line connects to the steam return line 6 after passing through the steam side of the steam-water heat exchanger 51. Control valves 9 are installed on both lines as needed. The steam distribution is controlled by the control valves 9.

[0033] The water side of the steam-water heat exchanger 51 is used to introduce a dechlorination solution (such as room temperature water or a specific chemical solution). Low-temperature exhaust steam transfers its heat to the dechlorination solution in the steam-water heat exchanger 51, raising its temperature.

[0034] The dissolving tank 52 has two inlets: one for introducing the raw wet solid waste (such as sludge), and the other connected to the water-side outlet of the steam-water heat exchanger 51 to receive the heated dechlorination solution. In the dissolving tank 52, the hot dechlorination solution is thoroughly mixed with the solid waste and washed to dissolve and remove some of the chlorine (especially organic chlorine) contained in the solid waste, completing the initial dechlorination. Typically, steam can treat ambient temperature water to 60-80°C. The liquid-to-solid ratio of the heated water to the sludge is 4:1. After stirring and washing, the upper mixed liquid is discharged.

[0035] The sludge outlet of the dissolving tank 52 is usually connected to the inlet of the first heating module 21 of the drying box 2 at the bottom, so that the solid waste after washing and dechlorination can enter the subsequent gradient drying process.

[0036] This embodiment achieves high-value conversion of extremely low-grade energy by adding a pretreatment unit 5 and utilizing the waste heat from the exhaust steam of the low-pressure cylinder 123 of the steam turbine 12—the lowest grade heat that is usually condensed and discarded—to heat the dechlorination solution. Before the solid waste enters the main drying system, physical washing is used to remove some chlorine, especially volatile organic chlorine, significantly reducing the risk of chlorine corrosion of the boiler 11 heating surface and the formation of dioxins during the subsequent high-temperature drying and incineration stages, thus improving the safety and environmental friendliness of the entire system.

[0037] In some embodiments, the first heating module 21, the second heating module 22 and the third heating module 23 are each provided with a heat source input terminal and a heat source output terminal, for supplying steam generated by the steam turbine 12 or molten salt in the molten salt storage system 3 to enter and flow out.

[0038] This embodiment further defines the structure of the heating module inside the drying oven 2.

[0039] Specifically, the first heating module 21, the second heating module 22, and the third heating module 23, which are connected in series inside the drying oven 2, share a common structural design: each heating module has an independent heat source input terminal and a heat source output terminal. This design makes the heating module a standardized heat exchange unit.

[0040] The heat source input end is used to allow external heat source medium (steam from turbine 12 or molten salt from molten salt thermal storage system 3) to flow into the module and indirectly exchange heat with the solid waste to be dried. The heat source output end is used to allow the heat source medium, whose temperature has decreased after heat exchange, to flow out so that it can return to the original system or enter the next stage.

[0041] In some specific embodiments, the first heating module 21 has heat sinks or a heat exchanger to form a passage for the external heat source medium to pass through, release heat, and then flow back. The heating module may also be equipped with a fan to purge the heat sinks or heat exchanger to heat the air and achieve the drying of solid waste.

[0042] In this embodiment, each heating module can be independently connected to heat sources of different grades, such as steam or molten salt. The system can flexibly switch or combine heat sources according to real-time operating conditions (such as unit load, molten salt temperature, and solid waste moisture content) by setting valves on the pipeline to optimize heat distribution. Secondly, this design greatly enhances the maintainability and scalability of the system. The maintenance or replacement of a single module does not affect the overall process and facilitates future upgrades or adaptation to other heat sources.

[0043] In some embodiments, the molten salt thermal storage system 3 includes: a first molten salt tank 31, a second molten salt tank 32, a molten salt-steam heat exchanger 33, and a first circulation pipeline 34. The steam side of the molten salt-steam heat exchanger 33 is connected to the exhaust pipe of the intermediate pressure cylinder 122 of the steam turbine 12. The first circulation pipeline 34 is sequentially connected to the liquid outlet of the first molten salt tank 31, the heat source input end of the third heating module 23, the heat source output end of the third heating module 23, the liquid inlet of the second molten salt tank 32, the liquid outlet of the second molten salt tank 32, the molten salt side of the molten salt-steam heat exchanger 33, and the liquid inlet of the first molten salt tank 31, so that the molten salt in the first circulation pipeline 34 absorbs and buffers the waste heat of the exhaust pipe of the intermediate pressure cylinder 122 of the steam turbine 12 and releases it to the third heating module 23.

[0044] In this embodiment, the molten salt thermal storage system 3 includes a first molten salt storage tank 31, a second molten salt storage tank 32, a molten salt-steam heat exchanger 33, and a first circulation pipeline 34. The first molten salt storage tank 31 is used to store and release high-temperature molten salt, and the second molten salt storage tank 32 is used to store and release low-temperature molten salt.

[0045] In some specific embodiments, the exhaust pipe of the intermediate pressure cylinder 122 of the steam turbine 12 is divided into two parallel lines. One line is directly connected to the steam inlet pipe of the low pressure cylinder 123, and the other line is connected to the steam inlet pipe of the low pressure cylinder 123 after passing through the steam side of the molten salt-steam heat exchanger 33. Regulating valves 9 are provided on both lines as needed to adjust the flow ratio of the two lines.

[0046] The first circulation pipeline 34 constitutes a complete molten salt circulation loop. Its specific connection sequence is as follows: sequentially connecting the outlet of the first molten salt storage tank 31 (high temperature tank), the heat source input end of the third heating module 23 in the drying box 2, the heat source output end of the third heating module 23, the inlet of the second molten salt storage tank 32 (low temperature tank), the outlet of the second molten salt storage tank 32, the molten salt side of the molten salt-steam heat exchanger 33, and the inlet of the first molten salt storage tank 31.

[0047] In this cycle, the low-temperature molten salt from the second molten salt storage tank 32 absorbs the waste heat from the exhaust steam from the intermediate pressure cylinder 122 of the steam turbine 12 in the molten salt-steam heat exchanger 33, and its temperature rises to become high-temperature molten salt, which is then stored in the first molten salt storage tank 31. When the third heating module 23 needs heat, the high-temperature molten salt is pumped out from the first molten salt storage tank 31, flows through the third heating module 23, and releases heat to dry the solid waste at the highest temperature level. The cooled molten salt then returns to the second molten salt storage tank 32, completing a heat release-heat storage cycle.

[0048] In addition, when the thermal power unit 1 is running at high load, heat storage can be achieved through the phase change of molten salt in the first molten salt storage tank 31 and the second molten salt storage tank 32, or the flow rate of molten salt can be adjusted by valves. For example, increasing the flow rate into the first molten salt storage tank 31 can increase the amount of high-temperature molten salt to achieve further heat storage, or increasing the number or capacity of the first molten salt storage tank 31, etc.

[0049] Technical Effects: This embodiment directly extracts heat from the exhaust steam of the intermediate-pressure cylinder 122 of the steam turbine 12 (whose grade is significantly higher than that of the exhaust steam or extraction steam of the low-pressure cylinder 123) through the molten salt-steam heat exchanger 33, and stores it in high density in molten salt. This achieves efficient recovery of the intermediate-grade waste heat of the thermal power unit 1, thus adapting to the buffer utilization of waste heat of the thermal power unit 1 under different operating conditions. It enables heat storage when the unit load is high and there is surplus intermediate-pressure exhaust steam, and stable heat release when the unit load is low or solid waste needs to be treated, perfectly resolving the heat supply and demand contradiction between peak-shaving operation of the thermal power unit 1 and continuous solid waste treatment.

[0050] In some embodiments, the molten salt thermal storage system 3 further includes a molten salt-molten salt heat exchanger 35 and a second circulation pipeline 36. The molten salt-molten salt heat exchanger 35 has a heat source molten salt side and a cold source molten salt side. The second circulation pipeline 36 connects the cold source molten salt side of the molten salt-molten salt heat exchanger 35, the heat source input end and the heat source output end of the second heating module 22. The heat source molten salt side is located between the heat source output end of the third heating module 23 and the liquid inlet of the second molten salt storage tank 32, so that the molten salt in the first circulation pipeline 34 heats the molten salt in the second circulation pipeline 36.

[0051] In this embodiment, the molten salt thermal storage system 3 also includes a molten salt-molten salt heat exchanger 35 and a second circulation pipeline 36. The molten salt-molten salt heat exchanger 35 has a heat source molten salt side and a cold source molten salt side that are isolated from each other but can exchange heat (e.g., a shell-and-tube heat exchanger with a shell side and a tube side).

[0052] The second circulation pipeline 36 is an independent molten salt circulation loop. It connects the cold source molten salt side outlet of the molten salt-molten salt heat exchanger 35, the heat source input end of the second heating module 22 in the drying oven 2, the heat source output end of the second heating module 22, and finally returns to the cold source molten salt side inlet of the molten salt-molten salt heat exchanger 35.

[0053] The molten salt side of the molten salt heat exchanger 35 is connected in series on the first circulation line 34, specifically between the heat source output of the third heating module 23 and the inlet of the second molten salt storage tank 32 (cryogenic tank). This means that the molten salt (from the first circulation line 34) flowing out of the third heating module 23, which has already released some heat for maximum temperature drying but is still at a relatively high temperature, will first flow through the heat source side of the molten salt heat exchanger 35 before returning to the cryogenic tank. Here, the remaining heat it carries is used to heat the molten salt in the second circulation line 36, thereby heating the second heating module 22.

[0054] In this embodiment, the temperature of the high-temperature molten salt in the first circulation pipeline 34, after servicing the third heating module 23, is still significantly higher than the operating temperature required by the second heating module 22 (e.g., 200-250°C). By adding a molten salt-molten salt heat exchanger 35, this portion of the secondary high-temperature waste heat is effectively recovered and used to heat the molten salt in the second circulation pipeline 36, thereby maximizing the utilization of single-use heat storage energy. Furthermore, the independent second circulation pipeline 36 can be adapted to the temperature requirements of the second heating module 22. This avoids the energy waste caused by directly using a higher-temperature heat source (such as molten salt or steam from a high-temperature tank) for heating, and also avoids difficulties in controlling the drying process that may result from a mismatch in heat source temperatures. This is also key to achieving the requirements of tiered heat utilization and gradient dehydration.

[0055] In some embodiments, the first circulation line 34 and the second circulation line 36 are provided with at least one of a pump 7, a shut-off valve 8, and a regulating valve 9.

[0056] In this embodiment, fluid control components, including at least one of a pump 7, a shut-off valve 8, and a regulating valve 9, may be installed on the first circulation pipeline 34 and the second circulation pipeline 36. These components are arranged at key locations in the pipelines according to process requirements.

[0057] Pump 7 (e.g., molten salt pump 7) provides power for the flow of molten salt in the circulation pipeline, overcomes pipeline resistance, and ensures that the molten salt flows through the heat exchanger and heating module at the designed flow rate. Shut-off valve 8 is used to completely connect or disconnect the flow in a section of the pipeline, used during system startup, shutdown, switching of operating conditions, or when a device needs to be isolated for maintenance, ensuring system operational safety and ease of maintenance. Regulating valve 9 is used to precisely control the flow rate of molten salt through a section of the pipeline, thereby achieving continuous and fine adjustment of the heat supplied by the heating module.

[0058] The design of pump 7 and valves described above allows for proactive control of the heat storage and release process of molten salt. For example, the amount of molten salt entering the first molten salt storage tank 31 can be increased to facilitate heat storage.

[0059] Simultaneously, on-demand heat distribution is achieved: by independently controlling the molten salt flow rate in the two circulation pipelines through regulating valve 9, the heat power delivered to the second and third heating modules 23 can be precisely adjusted, thereby achieving temperature control at different drying stages. Meanwhile, the shut-off valve 8 ensures that any heating module or molten salt storage tank can be safely isolated and maintained without affecting the operation of other parts, improving system availability and maintainability. After these control components are linked with the power plant's main control system, the molten salt circulation state can be automatically and quickly adjusted based on parameters such as the turbine 12 load (excess heat), solid waste treatment volume, and target drying degree. This enables the solid waste treatment system to intelligently adapt to the wide-load peak-shaving operation of the thermal power unit 1, achieving coordinated operation of heat recovery and solid waste disposal.

[0060] In some embodiments, the thermal power unit 1 coupled solid waste treatment system further includes a steam return pipeline 6. One end of the steam return pipeline 6 is connected to the exhaust pipeline of the low-pressure cylinder 123 of the steam turbine 12, and the other end of the steam return pipeline 6 is connected to the boiler 11. The steam return pipeline 6 is used to supply steam into the boiler 11 to condition the solid waste entering the boiler 11. The extraction pipeline of the low-pressure cylinder 123 of the steam turbine 12 is connected to the heat source input end of the first heating module 21, and the heat source output end of the first heating module 21 is connected to the steam return pipeline 6.

[0061] In this embodiment, a steam return pipeline 6 is added. One end of this pipeline is connected to the exhaust pipeline of the low-pressure cylinder 123 of the steam turbine 12, and the other end is connected to the boiler 11. Its function is to transport a portion of the steam from the exhaust of the low-pressure cylinder 123 back to the boiler 11 for steam conditioning of the dried and pulverized solid waste particles that are about to enter the boiler 11 for combustion. Steam conditioning can improve the flowability and combustion characteristics of the solid waste particles.

[0062] In this embodiment, the heat source circulation of the first heating module 21 is also integrated into the aforementioned steam return pipeline 6. Specifically, the connection is as follows: the extraction steam pipeline of the low-pressure cylinder 123 of the steam turbine 12 is connected to the heat source input end of the first heating module 21 to provide a heat source for preliminary drying. The heat source output end of the first heating module 21 (i.e., the condensate or low-temperature steam formed after heat exchange) is connected to the steam return pipeline 6, so that this part of the fluid can flow into the return pipeline and return to the boiler 11.

[0063] In some specific embodiments, the exhaust pipe of the low-pressure cylinder 123 of the steam turbine 12 is divided into two parallel lines: one line is equipped with a condenser and is ultimately connected to the steam return pipe 6; the other line is connected to the steam return pipe 6 after heat exchange on the steam side of the steam-water heat exchanger 51. Regulating valves 9 can be installed on both lines as needed to flexibly allocate the purpose of the exhaust steam (condensation or preheating of the dechlorination solution).

[0064] In some specific embodiments, the extraction steam pipeline of the low-pressure cylinder 123 of the steam turbine 12 is also divided into two parallel lines: one line is directly connected to the steam return pipeline 6; the other line flows through the first heating module 21, heats it, and then connects to the steam return pipeline 6. Both lines can also be equipped with regulating valves 9 as needed to adjust the steam flow rate used for preliminary drying.

[0065] In this embodiment, the condensate / low-temperature steam formed after the preliminary dried steam releases its sensible and latent heat still carries heat and is a pure working fluid. This condensate is introduced into the steam return pipeline 6 and returned to the boiler 11 system, avoiding blockage during sludge combustion, improving the smoothness of sludge transport, and reducing the system's water and heat consumption. Furthermore, by designing both the exhaust and extraction steam pipelines of the low-pressure cylinder 123 as parallel adjustable branches, the system can flexibly select its operating mode according to the unit's real-time load, solid waste treatment requirements, and the boiler 11's status. For example, when maximum solid waste treatment is required, more extraction steam can be directed to the first heating module 21; when the unit is under low load and the exhaust steam pressure and temperature are low, the valves can be adjusted to ensure sufficient steam with suitable parameters for reflux conditioning, thereby ensuring the stability of combustion on the boiler 11 side.

[0066] In some embodiments, a heater 61 and / or a deaerator 62 are provided on the steam return line 6.

[0067] In this embodiment, a heater 61 and / or a deaerator 62 are selectively provided on the steam return line 6.

[0068] The function of heater 61 is to reheat the return steam in the pipeline (which may include low-temperature steam or condensate from the heat source output of the first heating module 21). By precisely controlling the heating amount, the temperature of the return medium can be raised to a more suitable and stable range to ensure that its conditioning effect on solid waste particles is optimal after entering boiler 11, and to avoid thermal stress or efficiency reduction problems that may be caused by the direct entry of low-temperature medium into the boiler 11 system. The location and number of heaters 61 can be set as needed.

[0069] The function of deaerator 62 is to remove dissolved oxygen and other non-condensable gases from the return medium. This effectively prevents these gases from entering boiler 11 with the working medium, thereby avoiding oxygen corrosion of high-temperature and pressure-bearing components such as economizer and water-cooled walls of boiler 11, extending the service life of key equipment, and ensuring the long-term safe and stable operation of boiler 11.

[0070] In some embodiments, the operating temperature range of the first heating module 21 is 120-150℃.

[0071] In some embodiments, the operating temperature range of the second heating module 22 is 200-250℃.

[0072] In some embodiments, the operating temperature range of the third heating module 23 is 300-350℃.

[0073] In this embodiment, the operating temperature range of the first heating module 21 is set to 120-150℃. This temperature range can quickly evaporate surface water and some interstitial water, reducing the sludge moisture content from 60%-80% after washing to 40%-50%. This avoids the re-adsorption or reaction of organic chlorine removed by washing, and also prevents excessive decomposition of organic matter in the sludge, ensuring the energy efficiency of subsequent heating.

[0074] The operating temperature range of the second heating module 22 is set to 200-250℃. This mid-temperature range is mainly used for deep removal of bound water from solid waste, further reducing the moisture content to 20%-30%, thus reducing the energy consumption of subsequent high-temperature heating. It also removes volatile light organic matter from the lightly pyrolyzed sludge, preventing these substances from agglomerating and sticking together in the coal mill 4, while also preventing the generation of large amounts of harmful gases (such as dioxins, with a peak generation temperature >350℃).

[0075] The operating temperature range of the third heating module 23 is set to 300-350℃. This high-temperature range is designed to complete the final drying of solid waste and moderately pyrolyze some of the recalcitrant organic matter, so that the solid waste is finally formed into dry, loose granules. This meets the feed moisture requirements of the coal mill 4 (usually <20%), preventing clumping and equipment blockage during coal grinding. Moderately pyrolyzing some of the recalcitrant organic matter in the sludge reduces sludge viscosity and improves coal grinding efficiency. At the same time, the temperature does not reach the dangerous range for the large-scale formation of dioxins (350-800℃) and avoids the softening temperature of ash in the sludge (usually >400℃), so as not to cause ash slagging that would affect subsequent treatment.

[0076] In some embodiments, the coal mill 4 also includes a flue gas inlet, which is connected to the tail flue of the boiler 11 via a flue gas pipe 13.

[0077] Specifically, in addition to a solid waste inlet connected to the discharge port of the third heating module 23 and an outlet connected to the coal feed port of the boiler 11, the coal mill 4 is also equipped with an extra flue gas inlet. This flue gas inlet is connected to the tail flue of the boiler 11 via a flue gas duct 13. Specifically, a shut-off valve 8 and / or a regulating valve 9 are installed on the flue gas duct 13 to control, shut off, or finely regulate the flow rate of the high-temperature flue gas introduced into the coal mill 4.

[0078] After being deeply dried by the third heating module 23, the solid waste enters the coal mill 4, where it is not only mechanically crushed, but also subjected to final contact drying and preheating by the high-temperature flue gas (usually still 300-600℃) introduced from the tail flue of the boiler 11.

[0079] In this embodiment, the waste heat of the flue gas at the tail end of the boiler 11 is introduced into the coal mill 4, which directly conducts efficient convective heat exchange with the solid waste particles being crushed. This can further remove trace amounts of residual moisture and preheat the fuel, with almost no additional energy consumption. In addition, the flue gas flow can also improve the fluidity of the solid waste, making it easier for the solid waste to enter the boiler 11 quickly and smoothly.

[0080] The regulating valve 9 on the flue gas duct 13 can adjust the amount of flue gas introduced in real time and accurately according to the outlet temperature of the coal mill 4 or the characteristics of the solid waste, so as to achieve temperature control inside the coal mill 4 and prevent the dried solid waste from overheating, sticking together or coking.

[0081] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0084] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0085] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A thermal power unit coupled solid waste treatment system, characterized in that, include: Thermal power unit (1), the thermal power unit (1) includes a boiler (11) and a steam turbine (12); The drying chamber (2) is provided with a first heating module (21), a second heating module (22) and a third heating module (23) arranged in series. The first heating module (21) is used to introduce solid waste, and the solid waste is dried by passing through each heating module in sequence. The first heating module (21) is connected to the extraction steam pipeline of the steam turbine (12) to use the residual heat of steam in the extraction steam pipeline to perform preliminary drying of the solid waste. Molten salt thermal storage system (3) is connected to the steam turbine (12) to absorb and buffer the excess heat of the steam turbine (12), and the molten salt thermal storage system (3) is connected to the second heating module (22) and the third heating module (23) to provide heat to the second heating module (22) and the third heating module (23); The coal mill (4) has its inlet connected to the outlet of the third heating module (23) and its outlet connected to the coal feed port of the boiler (11), for conveying the solid waste dried by the third heating module (23) to the boiler (11) for co-firing.

2. The thermal power unit coupled solid waste treatment system according to claim 1, characterized in that, It also includes a preprocessing unit (5), which includes: A steam-water heat exchanger (51) is provided, the steam side of which is connected to the exhaust pipe of the low-pressure cylinder (123) of the steam turbine (12), and the water side of which is used to introduce a dechlorination solution. The dissolving tank (52) has an inlet for introducing the solid waste and is connected to the water-side outlet of the steam-water heat exchanger (51) to receive the heated dechlorination solution and wash and dechlorinate the solid waste. The outlet of the dissolving tank (52) is connected to the feed inlet of the first heating module (21).

3. The thermal power unit coupled solid waste treatment system according to claim 1, characterized in that, The first heating module (21), the second heating module (22) and the third heating module (23) are all provided with a heat source input end and a heat source output end, which are used to allow steam generated by the steam turbine (12) or molten salt in the molten salt heat storage system (3) to enter and flow out.

4. The thermal power unit coupled solid waste treatment system according to claim 3, characterized in that, The molten salt thermal storage system (3) includes: First molten salt storage tank (31) and second molten salt storage tank (32); Molten salt-steam heat exchanger (33), the steam side of which is connected to the exhaust pipe of the intermediate pressure cylinder (122) of the steam turbine (12); The first circulation pipeline (34) is sequentially connected to the outlet of the first molten salt tank (31), the heat source input end of the third heating module (23), the heat source output end of the third heating module (23), the inlet of the second molten salt tank (32), the outlet of the second molten salt tank (32), the molten salt side of the molten salt-steam heat exchanger (33), and the inlet of the first molten salt tank (31), so that the molten salt in the first circulation pipeline (34) can absorb and buffer the residual heat of the exhaust pipe of the intermediate pressure cylinder (122) of the steam turbine (12) and release it to the third heating module (23).

5. The thermal power unit coupled solid waste treatment system according to claim 4, characterized in that, The molten salt thermal storage system (3) also includes: Molten salt-molten salt heat exchanger (35), the molten salt-molten salt heat exchanger (35) having a heat source molten salt side and a cold source molten salt side; The second circulation pipeline (36) is connected to the cold source molten salt side of the molten salt-molten salt heat exchanger (35), the heat source input end and the heat source output end of the second heating module (22); The heat source molten salt side is located between the heat source output end of the third heating module (23) and the liquid inlet of the second molten salt storage tank (32) so that the molten salt in the first circulation pipeline (34) heats the molten salt in the second circulation pipeline (36).

6. The thermal power unit coupled solid waste treatment system according to claim 5, characterized in that, The first circulation line (34) and the second circulation line (36) are equipped with at least one of a pump (7), a shut-off valve (8), and a regulating valve (9).

7. The thermal power unit coupled solid waste treatment system according to claim 3, characterized in that, It also includes a steam return pipe (6), one end of which is connected to the exhaust pipe of the low-pressure cylinder (123) of the steam turbine (12), and the other end of which is connected to the boiler (11). The steam return pipe (6) is used to supply steam into the boiler (11) to condition the solid waste entering the boiler (11); and, The extraction steam pipeline of the low-pressure cylinder (123) of the steam turbine (12) is connected to the heat source input end of the first heating module (21), and the heat source output end of the first heating module (21) is connected to the steam return pipeline (6).

8. The thermal power unit coupled solid waste treatment system according to claim 7, characterized in that, A heater (61) and / or a deaerator (62) are provided on the steam return line (6).

9. The thermal power unit coupled solid waste treatment system according to any one of claims 1-8, characterized in that, The operating temperature range of the first heating module (21) is 120-150℃; and / or, The operating temperature range of the second heating module (22) is 200-250℃; and / or, The operating temperature range of the third heating module (23) is 300-350℃.

10. The thermal power unit coupled solid waste treatment system according to claim 9, characterized in that, The coal mill (4) also includes a flue gas inlet, which is connected to the tail flue of the boiler (11) via a flue gas pipe (13).

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