A high-temperature solid discharge waste heat recovery system and a control method thereof

Abstract

The application discloses a high-temperature solid discharge waste heat recovery system and a control method thereof, which comprises a high-temperature discharge cooling device, a high-temperature gas-powder separation device, a medium-temperature discharge cooling device, a medium-temperature gas-powder separation device, a low-temperature discharge cooling device, a low-temperature gas-powder separation device, a waste heat boiler, a dust remover and a circulating fan. The application adopts a segmented and stepped cooling mode to recover the heat of high-temperature solid discharge, so as to respectively control the air flow temperature of a high-temperature zone before being sent into a high-temperature superheater of the waste heat boiler, a medium-temperature zone before being sent into an evaporator and a low-temperature zone before being sent into a coal economizer, so as to realize waste heat recovery under the condition of higher air flow temperature and higher steam parameters. Meanwhile, the heat absorption amount of the waste heat boiler in different temperature zones can be distributed and adjusted. Furthermore, the air flow cooling medium is recycled, so that the waste heat can be further recovered, the efficiency of high-temperature solid discharge waste heat recovery is improved, and the carbon dioxide emission of the system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste heat recovery and energy saving and low carbon, and particularly relates to a high-temperature solid discharge waste heat recovery system and a control method thereof. BACKGROUND

[0002] With the gradual implementation of the carbon peak and carbon neutralization policy, especially under the guidance of the carbon emission reduction policy, the efficient recovery technology of high-temperature solid discharge waste heat is one of the key energy-saving and carbon emission reduction technologies, and is increasingly valued in high-carbon-emission enterprises such as coal-fired power generation, lime production, and cement.

[0003] There is a large amount of high-temperature solid discharge waste heat in the industrial production process, such as the high-temperature discharge of power station boilers for coal-fired power generation, calcination kilns for light-burned magnesia, and cement clinker calcination kilns, and the discharge temperature is even as high as 900 DEG C or above. Therefore, recovering and efficiently utilizing the waste heat of these high-temperature solid discharges has become one of the important contents of enterprise energy saving and carbon emission reduction.

[0004] At present, the cooling methods for high-temperature solid discharges mainly include water-cooled rollers, fluidized bed air-water cooling slag coolers, and grate coolers. The water-cooled roller can only produce low-pressure hot water or steam, and cannot achieve efficient utilization of high-temperature waste heat. The fluidized bed air-water cooling slag cooler can produce high-temperature and high-pressure steam, but generally adopts a single-stage cooling method, and the discharge temperature is generally higher than 300 DEG C, making it difficult to achieve full recovery of high-temperature solid discharge waste heat. The grate cooler commonly used in the cement industry is used to cool high-temperature clinker, and a waste heat boiler is used to recover waste heat. However, due to the connection of the space above the grate cooler, the cooling air is partially mixed in the high-temperature and low-temperature zones in the space above the grate cooler, so that the exhaust gas temperature in the high-temperature zone of the waste heat recovery power generation system is generally about 450 DEG C, and efficient utilization of waste heat for power generation has not been achieved.

[0005] For a waste heat recovery power generation system that recovers waste heat from flue gas by using a waste heat boiler, the higher the pressure and temperature parameters of the superheated steam generated by the waste heat boiler, the higher the power generation efficiency of the system. However, the distribution of the heat absorption amount of superheated steam, the heat absorption amount of water evaporation, and the heat absorption amount of preheating is closely related to the feedwater temperature of the waste heat boiler, the temperature and pressure of the superheated steam; therefore, under the premise of as high as possible flue gas temperature entering the waste heat boiler, the flue gas temperatures before entering the superheater, the evaporator, and the economizer must be matched with the heat absorption amount of the corresponding heating surface, so as to achieve efficient utilization of waste heat recovery. SUMMARY

[0006] The present application aims to overcome the deficiencies in the prior art, and provides a high-temperature solid discharge waste heat recovery system and a control method thereof, which recovers the heat of high-temperature solid discharges by using a segmented and stepped cooling method, so as to achieve efficient recovery and utilization of high-temperature solid discharge waste heat.

[0007] To solve the prior art problems, the application discloses a high-temperature solid discharge waste heat recovery system, which comprises a circulating fan, a dust collector, a waste heat boiler, a high-temperature superheater, an evaporator, a coal economizer, a waste heat boiler exhaust port, a low-temperature zone gas inlet port of the coal economizer, a medium-temperature zone gas inlet port of the evaporator, a high-temperature zone gas inlet port of the high-temperature superheater, a high-temperature gas-powder separation device, a high-temperature discharge cooling device, a medium-temperature discharge cooling device, a low-temperature discharge cooling device, a dust collector gas inlet port, a dust collector exhaust port, a medium-temperature gas-powder separation device and a low-temperature gas-powder separation device.

[0008] The high-temperature discharge cooling device, the medium-temperature discharge cooling device and the low-temperature discharge cooling device are each provided with a feed inlet, a discharge pipe, a return inlet, a gas inlet port and an exhaust port.

[0009] The high-temperature gas-powder separation device, the medium-temperature gas-powder separation device and the low-temperature gas-powder separation device are each provided with a gas inlet port, an exhaust port and a discharge pipe.

[0010] The high-temperature discharge cooling device feed inlet is used for inputting high-temperature solid powder, the high-temperature discharge cooling device discharge pipe is connected to the medium-temperature discharge cooling device feed inlet, the high-temperature discharge cooling device return inlet is connected to the high-temperature gas-powder separation device discharge pipe, and the high-temperature discharge cooling device exhaust port is connected to the high-temperature gas-powder separation device gas inlet port.

[0011] The medium-temperature discharge cooling device discharge pipe is connected to the low-temperature discharge cooling device feed inlet, the medium-temperature discharge cooling device return inlet is connected to the medium-temperature gas-powder separation device discharge pipe, and the medium-temperature discharge cooling device exhaust port is connected to the medium-temperature gas-powder separation device gas inlet port.

[0012] The low-temperature discharge cooling device discharge pipe is connected to a bin, the low-temperature discharge cooling device return inlet is connected to the low-temperature gas-powder separation device discharge port, and the low-temperature discharge cooling device exhaust port is connected to the low-temperature gas-powder separation device gas inlet port.

[0013] The high-temperature superheater, the evaporator and the coal economizer are sequentially arranged in the waste heat boiler from top to bottom; the high-temperature gas-powder separation device exhaust port is connected to the high-temperature superheater through the high-temperature superheater high-temperature zone gas inlet port; the medium-temperature gas-powder separation device exhaust port is connected to the evaporator through the evaporator medium-temperature zone gas inlet port; the low-temperature gas-powder separation device exhaust port is connected to the coal economizer through the coal economizer low-temperature zone gas inlet port; the waste heat boiler is provided with a waste heat boiler exhaust port and a discharge port for connecting to a bin, the waste heat boiler exhaust port is connected to the dust collector through the dust collector gas inlet port, the dust collector is provided with a discharge port for connecting to the bin, the dust collector is connected to the circulating fan gas inlet port through the dust collector exhaust port, and the circulating fan gas outlet port is connected to the high-temperature discharge cooling device, the medium-temperature discharge cooling device and the low-temperature discharge cooling device gas inlet ports through pipes.

[0014] Further, a high-temperature section air volume regulating valve is arranged on the pipeline connecting the outlet of the circulating fan and the inlet of the high-temperature discharge cooling device.

[0015] Further, a medium-temperature section air volume regulating valve is arranged on the pipeline connecting the outlet of the circulating fan and the inlet of the medium-temperature discharge cooling device.

[0016] Further, a low-temperature section air volume regulating valve is arranged on the pipeline connecting the outlet of the circulating fan and the inlet of the low-temperature discharge cooling device.

[0017] Further, the lower part of the high-temperature discharge cooling device, the medium-temperature discharge cooling device and the low-temperature discharge cooling device is provided with an air chamber and a gasification air distribution plate connected with the inlet.

[0018] Further, the discharge pipe of the high-temperature discharge cooling device, the medium-temperature discharge cooling device and the low-temperature discharge cooling device is provided with a discharge control valve.

[0019] Further, the high-temperature gas-powder separation device, the medium-temperature gas-powder separation device and the low-temperature gas-powder separation device are cyclone gas-solid separators or inertial gas-solid separators.

[0020] Correspondingly, a control method of the high-temperature solid discharge waste heat recovery system is provided.

[0021] The high-temperature solid powder is sent into the high-temperature discharge cooling device through the inlet of the high-temperature discharge cooling device for first-stage cooling; the high-temperature exhaust gas generated by the high-temperature discharge cooling device enters the high-temperature gas-powder separation device for gas-solid preliminary separation, and the high-temperature exhaust gas of the high-temperature gas-powder separation device enters the high-temperature zone before the high-temperature superheater of the waste heat boiler through the inlet of the high-temperature zone before the high-temperature superheater, and then sequentially flows through the high-temperature superheater, the evaporator and the economizer to heat the superheated steam, the saturated water and the feed water in turn; the high-temperature discharge material separated from the high-temperature gas-powder separation device is sent back into the high-temperature discharge cooling device through the return inlet of the high-temperature discharge cooling device for circulation;

[0022] The discharge material of the high-temperature discharge cooling device is sent into the medium-temperature discharge cooling device through the discharge pipe for second-stage cooling; the medium-temperature exhaust gas generated by the medium-temperature discharge cooling device enters the medium-temperature gas-powder separation device for gas-solid preliminary separation, and the medium-temperature exhaust gas of the medium-temperature gas-powder separation device enters the medium-temperature zone before the evaporator of the waste heat boiler through the inlet of the medium-temperature zone before the evaporator, and then sequentially flows through the evaporator and the economizer to heat the saturated water and the feed water in turn; the medium-temperature discharge material separated from the medium-temperature gas-powder separation device is sent back into the medium-temperature discharge cooling device through the return inlet of the medium-temperature discharge cooling device for circulation.

[0023] The high-temperature exhaust material of the high-temperature exhaust material cooling device is discharged through an exhaust material pipe and then is transported to a storage bin for storage.

[0024] The exhaust material of the low-temperature exhaust material cooling device is discharged through an exhaust material pipe and then is transported to a storage bin for storage.

[0025] The exhaust gas of the waste heat boiler is sent to a dust collector through an air inlet of the dust collector for dust removal, the exhaust gas of the dust collector is sent to a circulating fan through an exhaust outlet of the dust collector, and after being pressurized by the circulating fan, the exhaust gas is sent to air inlet chambers of the high-temperature exhaust material cooling device, the medium-temperature exhaust material cooling device and the low-temperature exhaust material cooling device, respectively, to realize circulation of cooling air volume, and through air volume circulation and heat recycling, the waste heat contained in the exhaust gas is fully recycled.

[0026] The present application has the beneficial effects that:

[0027] The present application adopts a segmented and stepped cooling mode to recycle the heat of the high-temperature solid exhaust material, and uses the heat to control the temperature of the gas flow sent to the high-temperature zone before the high-temperature superheater of the waste heat boiler, the medium-temperature zone before the evaporator and the low-temperature zone before the economizer, respectively; under the premise of improving the flue gas temperature entering the waste heat boiler as much as possible, the flue gas temperatures entering the superheater, the evaporator and the economizer of the waste heat boiler are matched with the heat absorption of the corresponding heating surfaces, so that the heat recovery is efficiently utilized. At the same time, the flue gas internal circulation measure is adopted to fully recycle the waste heat of the flue gas, and the maximum heat recovery of the high-temperature solid exhaust material is realized. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural arrangement schematic diagram of the present application.

[0029] Figure 2 is a structural arrangement schematic diagram of the present application.

[0030] Figure 3 is a structural arrangement schematic diagram of the present application.

[0031] Figure 1The components are as follows: 1. Circulating fan; 2. Dust collector; 3. Waste heat boiler; 4. High-temperature superheater; 5. Evaporator; 6. Economizer; 7. Waste heat boiler exhaust port; 8. Air inlet of the low-temperature zone before the economizer; 9. Air inlet of the medium-temperature zone before the evaporator; 10. Air inlet of the high-temperature zone before the high-temperature superheater; 11. High-temperature gas-powder separator; 12. High-temperature discharge cooling device; 13. Medium-temperature discharge cooling device; 14. Low-temperature discharge cooling device; 15. High-temperature section airflow regulating valve; 16. Medium-temperature section airflow regulating valve; 17. Low-temperature section airflow regulating valve; 18. Dust collector inlet; 19. Dust collector exhaust port; 20. Medium-temperature gas-powder separator; 21. Low-temperature gas-powder separator.

[0032] Figure 2 In the middle: 30, the body of the discharge cooling device; 30-1, the exhaust port; 30-2, the feed port; 30-3, the air inlet of the air chamber; 30-4, the air chamber; 30-5, the return port; 30-6, the gasification air distribution plate; 30-7, the discharge control valve; 30-8, the discharge pipe.

[0033] Figure 3 40. Cyclone air-powder separator body; 40-1. Exhaust port; 40-2. Air inlet; 40-3. Discharge pipe. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0035] like Figure 1 As shown, a high-temperature solid discharge waste heat recovery system of the present invention includes: a circulating fan 1, a dust collector 2, a waste heat boiler 3, a high-temperature superheater 4, an evaporator 5, an economizer 6, a waste heat boiler exhaust port 7, an air inlet 8 in the low-temperature zone before the economizer, an air inlet 9 in the medium-temperature zone before the evaporator, an air inlet 10 in the high-temperature zone before the high-temperature superheater, a high-temperature gas-powder separator 11, a high-temperature discharge cooling device 12, a medium-temperature discharge cooling device 13, a low-temperature discharge cooling device 14, an air inlet 18 of the dust collector, an exhaust port 19 of the dust collector, a medium-temperature gas-powder separator 20, and a low-temperature gas-powder separator 21.

[0036] The high-temperature discharge cooling device 12, the medium-temperature discharge cooling device 13, and the low-temperature discharge cooling device 14 are all equipped with a feed inlet, a discharge pipe, a return inlet, an air inlet, and an exhaust outlet.

[0037] The high-temperature gas-powder separator 11, the medium-temperature gas-powder separator 20, and the low-temperature gas-powder separator 21 are all equipped with an air inlet, an exhaust outlet, and a discharge pipe.

[0038] The feeding port of the high-temperature discharging cooling device 12 is used for inputting high-temperature solid powder, the discharging pipe of the high-temperature discharging cooling device 12 is connected with the feeding port of the medium-temperature discharging cooling device 13, the returning port of the high-temperature discharging cooling device 12 is connected with the discharging pipe of the high-temperature gas-powder separation device 11, and the exhaust port of the high-temperature discharging cooling device 12 is connected with the gas inlet of the high-temperature gas-powder separation device 11;

[0039] The discharging pipe of the medium-temperature discharging cooling device 13 is connected with the feeding port of the low-temperature discharging cooling device 14, the returning port of the medium-temperature discharging cooling device 13 is connected with the discharging pipe of the medium-temperature gas-powder separation device 20, and the exhaust port of the medium-temperature discharging cooling device 13 is connected with the gas inlet of the medium-temperature gas-powder separation device 20;

[0040] The discharging pipe of the low-temperature discharging cooling device 14 is connected with the stock bin, the returning port of the low-temperature discharging cooling device 14 is connected with the discharging port of the low-temperature gas-powder separation device 21, and the exhaust port of the low-temperature discharging cooling device 14 is connected with the gas inlet of the low-temperature gas-powder separation device 21;

[0041] The high-temperature superheater 4, the evaporator 5 and the coal economizer 6 are sequentially arranged in the waste heat boiler 3 from top to bottom; the exhaust port of the high-temperature gas-powder separation device 11 is connected with the high-temperature superheater 4 through the gas inlet 10 of the high-temperature zone before the high-temperature superheater; the exhaust port of the medium-temperature gas-powder separation device 20 is connected with the evaporator 5 through the gas inlet 9 of the medium-temperature zone before the evaporator; the exhaust port of the low-temperature gas-powder separation device 21 is connected with the coal economizer 6 through the gas inlet 8 of the low-temperature zone before the coal economizer; the waste heat boiler 3 is provided with a discharging port for connecting with the stock bin and a waste heat boiler exhaust port 7, the waste heat boiler exhaust port 7 is connected with the dust collector 2 through the gas inlet 18 of the dust collector, the dust collector 2 is connected with the gas inlet of the circulating fan 1 through the exhaust port 19 of the dust collector, and the gas outlet of the circulating fan 1 is connected with the gas inlets of the high-temperature discharging cooling device 12, the medium-temperature discharging cooling device 13 and the low-temperature discharging cooling device 14 through pipes.

[0042] In the present embodiment, the high-temperature solid discharge is the 950℃ solid semi-clinker produced by the cement raw material calcination in the external combustion kiln. The 950℃ high-temperature solid discharge is fed into the high-temperature solid discharge cooling device 12 through the feeding port of the high-temperature solid discharge cooling device 12 to be cooled in the first stage. The high-temperature exhaust gas produced by the high-temperature solid discharge cooling device 12 enters the high-temperature gas-powder separation device 11 to be preliminarily separated. The high-temperature exhaust gas of the high-temperature gas-powder separation device 11 enters the high-temperature area before the high-temperature superheater 4 through the gas inlet 10 of the high-temperature area before the high-temperature superheater 4 of the waste heat boiler 3, and then sequentially flows through the high-temperature superheater 4, the evaporator 5 and the economizer 6 to heat the superheated steam, the saturated water and the feed water in sequence. The 700~750℃ high-temperature solid discharge separated by the high-temperature gas-powder separation device 11 is fed back into the high-temperature solid discharge cooling device 12 through the return port of the upper part of the high-temperature solid discharge cooling device 12 to be recycled. In the present embodiment, in order to fully recover the waste heat and obtain higher power generation efficiency, the waste heat boiler adopts high-temperature and high-pressure, and the superheated steam parameter at the outlet of the high-temperature superheater 4 is 9.8Mpa, 540℃.

[0043] The 700~750℃ solid discharge of the high-temperature solid discharge cooling device 12 is fed into the medium-temperature solid discharge cooling device 13 through the discharge pipe to be cooled in the second stage. The 600~650℃ medium-temperature exhaust gas produced by the medium-temperature solid discharge cooling device 13 enters the medium-temperature gas-powder separation device 20 to be preliminarily separated. The medium-temperature exhaust gas of the medium-temperature gas-powder separation device 20 enters the medium-temperature area before the evaporator 5 through the gas inlet 9 of the medium-temperature area before the evaporator 5 of the waste heat boiler 3, and then sequentially flows through the evaporator 5 and the economizer 6 to heat the saturated water and the feed water in sequence. The 350~400℃ medium-temperature solid discharge separated by the medium-temperature gas-powder separation device 20 is fed back into the medium-temperature solid discharge cooling device 13 through the return port of the upper part of the medium-temperature solid discharge cooling device 13 to be recycled.

[0044] The 350~400℃ solid discharge of the medium-temperature solid discharge cooling device 13 is fed into the low-temperature solid discharge cooling device 14 through the discharge pipe to be cooled in the third stage. The 300~350℃ low-temperature exhaust gas produced by the low-temperature solid discharge cooling device 14 enters the low-temperature gas-powder separation device 21 to be preliminarily separated. The low-temperature exhaust gas of the low-temperature gas-powder separation device 21 enters the low-temperature area before the economizer 6 through the gas inlet 8 of the low-temperature area before the economizer 6 of the waste heat boiler 3, and then flows through the economizer 6 to heat the feed water. The 100~150℃ low-temperature solid discharge separated by the low-temperature gas-powder separation device 21 is fed back into the low-temperature solid discharge cooling device 14 through the return port of the upper part of the low-temperature solid discharge cooling device 14 to be recycled.

[0045] The 100~150℃ solid discharge of the low-temperature solid discharge cooling device 14 is discharged through the discharge pipe and then transported to the stock bin for storage.

[0046] The exhaust gas from the waste heat boiler 3 is sent to the dust collector 2 through the inlet 18 for dust removal. The exhaust gas from the dust collector 2 then enters the circulating fan 1 through the exhaust port 19. After being pressurized by the circulating fan 1, it is sent to the inlet chambers of the high-temperature discharge cooling device 12, the medium-temperature discharge cooling device 13, and the low-temperature discharge cooling device 14 for cooling air circulation. Through air circulation and heat recycling, the waste heat contained in the exhaust gas can be fully recovered, improving the waste heat utilization efficiency of the system.

[0047] The outlet of the circulating fan 1 is connected to the air inlet chambers of the high-temperature discharge cooling device 12, the medium-temperature discharge cooling device 13, and the low-temperature discharge cooling device 14 via branch pipes. The branch pipes are equipped with high-temperature section air volume regulating valve 15, medium-temperature section air volume regulating valve 16, and low-temperature section air volume regulating valve 17, which are used to adjust the circulating air volume entering the high-temperature discharge cooling device 12, the medium-temperature discharge cooling device 13, and the low-temperature discharge cooling device 14, respectively, thereby adjusting their respective exhaust gas temperatures to meet the appropriate proportion requirements of heat absorption by each heating surface in the waste heat boiler 3.

[0048] In this embodiment, the high-temperature discharge cooling device 12, the medium-temperature discharge cooling device 13, and the low-temperature discharge cooling device 14 are fluidized or semi-fluidized gas-solid cooling devices, such as... Figure 2 The discharge cooling device shown includes a feed inlet 30-2, an exhaust outlet 30-1, a return outlet 30-5, an aeration air distribution plate 30-6, an air chamber inlet 30-3, an air chamber 30-4, a discharge pipe 30-8, and a discharge control valve 30-7.

[0049] The cooling fluidizing air of the discharge cooling device 30 is sent into the air chamber 30-4 through the air inlet 30-3, and then flows upward through the aeration air distribution plate 30-6 to cool the material on the aeration air distribution plate 30-6 by fluidization or semi-fluidization. The cooling air then passes through the material layer interface and is discharged from the discharge cooling device 30 through the exhaust port 30-2. The solid powder to be cooled is fed into the discharge cooling device 30 through the feed inlet 30-2. A discharge control valve 30-7 is installed on the discharge pipe 30-8 to control the flow rate of the material discharged from the bed, thereby controlling the height of the material layer and adjusting the temperature of the exhaust gas discharged through the exhaust port 30-2 as well as the temperature of the solid material in the material layer.

[0050] In this embodiment, the high-temperature gas-powder separator 11, the medium-temperature gas-powder separator 20, and the low-temperature gas-powder separator 21 are cyclone gas-solid separators, as shown in the example. Figure 3 The cyclone gas-solid separation device shown includes an air inlet 40-2, an exhaust outlet 40-1, and a discharge pipe 40-3.

[0051] The exhaust gas of the discharge cooling device 30 is sent into the cyclone gas-solid separation device 40 through the gas inlet 40-2, and cyclone gas-solid separation is performed, and the exhaust gas is discharged through the exhaust gas outlet 40-1, and the separated solid powder is returned to the discharge cooling device 30 through the discharge pipe 40-3 and the return port 30-5 of the discharge cooling device 30 connected thereto, and is circulated. The cyclone gas-solid separation device is used to separate part of the fine particle solid powder contained in the exhaust gas of the discharge cooling device, which can reduce the ash deposition on the heat receiving surface of the waste heat boiler and improve the heat absorption efficiency of the waste heat boiler.

[0052] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the drawings of the present application, the filled patterns are only for distinguishing layers and do not have any other limitations.

[0053] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A high-temperature solid discharge waste heat recovery system, characterized in that, include: Circulating fan (1), dust collector (2), waste heat boiler (3), high temperature superheater (4), evaporator (5), economizer (6), waste heat boiler exhaust port (7), air inlet of the low temperature zone before economizer (8), air inlet of the medium temperature zone before evaporator (9), air inlet of the high temperature zone before high temperature superheater (10), high temperature gas-powder separator (11), high temperature discharge cooling device (12), medium temperature discharge cooling device (13), low temperature discharge cooling device (14), air inlet of dust collector (18), exhaust port of dust collector (19), medium temperature gas-powder separator (20) and low temperature gas-powder separator (21); The high-temperature discharge cooling device (12), the medium-temperature discharge cooling device (13) and the low-temperature discharge cooling device (14) are all equipped with a feed inlet, a discharge pipe, a return inlet, an air inlet and an exhaust outlet; The high-temperature gas-powder separator (11), the medium-temperature gas-powder separator (20), and the low-temperature gas-powder separator (21) are all equipped with an air inlet, an exhaust outlet, and a discharge pipe; The inlet of the high-temperature discharge cooling device (12) is used to input high-temperature solid powder. The discharge pipe of the high-temperature discharge cooling device (12) is connected to the inlet of the medium-temperature discharge cooling device (13). The return port of the high-temperature discharge cooling device (12) is connected to the discharge pipe of the high-temperature gas-powder separator (11). The exhaust port of the high-temperature discharge cooling device (12) is connected to the air inlet of the high-temperature gas-powder separator (11). The discharge pipe of the medium-temperature discharge cooling device (13) is connected to the inlet of the low-temperature discharge cooling device (14), the return port of the medium-temperature discharge cooling device (13) is connected to the discharge pipe of the medium-temperature gas-powder separator (20), and the exhaust port of the medium-temperature discharge cooling device (13) is connected to the air inlet of the medium-temperature gas-powder separator (20). The discharge pipe of the low-temperature discharge cooling device (14) is connected to the silo, the return port of the low-temperature discharge cooling device (14) is connected to the discharge port of the low-temperature gas-powder separator (21), and the exhaust port of the low-temperature discharge cooling device (14) is connected to the air inlet of the low-temperature gas-powder separator (21). The high-temperature superheater (4), evaporator (5), and economizer (6) are arranged sequentially from top to bottom inside the waste heat boiler (3); the exhaust port of the high-temperature gas-powder separator (11) is connected to the high-temperature superheater (4) through the air inlet (10) of the high-temperature zone before the high-temperature superheater; the exhaust port of the medium-temperature gas-powder separator (20) is connected to the evaporator (5) through the air inlet (9) of the medium-temperature zone before the evaporator; the exhaust port of the low-temperature gas-powder separator (21) is connected to the economizer (6) through the air inlet (8) of the low-temperature zone before the economizer; the waste heat boiler ( 3) It is equipped with a waste heat boiler exhaust port (7) and a discharge port for connecting the silo. The waste heat boiler exhaust port (7) is connected to the dust collector (2) through the dust collector inlet (18). The dust collector (2) is equipped with a discharge port for connecting the silo. The dust collector (2) is connected to the inlet of the circulating fan (1) through the dust collector exhaust port (19). The outlet of the circulating fan (1) is connected to the inlet of the high temperature discharge cooling device (12), the medium temperature discharge cooling device (13) and the low temperature discharge cooling device (14) through pipes respectively.

2. The high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that, A high-temperature section air volume regulating valve (15) is installed on the pipe connecting the outlet of the circulating fan (1) and the inlet of the high-temperature discharge cooling device (12).

3. The high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that, A medium-temperature section air volume regulating valve (16) is installed on the pipe connecting the outlet of the circulating fan (1) and the inlet of the medium-temperature discharge cooling device (13).

4. The high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that, A low-temperature section air volume regulating valve (17) is installed on the pipe connecting the outlet of the circulating fan (1) and the inlet of the low-temperature discharge cooling device (14).

5. The high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that, The lower part of the high temperature discharge cooling device (12), the medium temperature discharge cooling device (13) and the low temperature discharge cooling device (14) is provided with a wind chamber and a gasification air distribution plate connected to the air inlet.

6. The high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that, The discharge pipes of the high-temperature discharge cooling device (12), the medium-temperature discharge cooling device (13), and the low-temperature discharge cooling device (14) are equipped with discharge control valves.

7. The high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that, The high-temperature gas-powder separation device (11), the medium-temperature gas-powder separation device (20) and the low-temperature gas-powder separation device (21) are cyclone gas-solid separators or inertial gas-solid separators.

8. The control method for a high-temperature solid discharge waste heat recovery system according to claim 1, characterized in that: High-temperature solid powder is fed into the high-temperature discharge cooling device (12) through the feed port for first-stage cooling; the high-temperature exhaust generated by the high-temperature discharge cooling device (12) enters the high-temperature gas-powder separator (11) for preliminary gas-solid separation; the high-temperature exhaust from the high-temperature gas-powder separator (11) enters the high-temperature zone before the high-temperature superheater (4) of the waste heat boiler (3) through the air inlet (10) in front of the high-temperature superheater, and then flows sequentially through the high-temperature superheater (4), evaporator (5) and economizer (6) to heat the superheated steam, saturated water and feedwater in sequence; the high-temperature discharge separated by the high-temperature gas-powder separator (11) is returned to the high-temperature discharge cooling device (12) through the return port for circulation; The discharge from the high-temperature discharge cooling device (12) is sent to the medium-temperature discharge cooling device (13) through the discharge pipe for the second stage of cooling; the medium-temperature exhaust gas generated by the medium-temperature discharge cooling device (13) enters the medium-temperature gas-powder separator (20) for preliminary gas-solid separation; the medium-temperature exhaust gas from the medium-temperature gas-powder separator (20) enters the medium-temperature zone in front of the evaporator (5) of the waste heat boiler (3) through the air inlet (9) in front of the medium-temperature zone of the evaporator, and then flows sequentially through the evaporator (5) and the economizer (6) to heat the saturated water and feedwater in turn; the medium-temperature discharge separated by the medium-temperature gas-powder separator (20) is returned to the inside of the medium-temperature discharge cooling device (13) through the return port of the medium-temperature discharge cooling device (13) for circulation; The discharge from the medium-temperature discharge cooling device (13) is sent to the low-temperature discharge cooling device (14) through the discharge pipe for third-stage cooling; the low-temperature exhaust gas generated by the low-temperature discharge cooling device (14) enters the low-temperature gas-powder separator (21) for preliminary gas-solid separation; the low-temperature exhaust gas from the low-temperature gas-powder separator (21) enters the low-temperature zone before the economizer (6) of the waste heat boiler (3) through the air inlet (8) in the low-temperature zone before the economizer, and then flows through the economizer (6) to heat the feedwater; the low-temperature discharge separated by the low-temperature gas-powder separator (21) is returned to the low-temperature discharge cooling device (14) through the return port of the low-temperature discharge cooling device (14) for circulation; The material discharged from the low-temperature discharge cooling device (14) is discharged through the discharge pipe and then transported to the storage bin; The exhaust gas from the waste heat boiler (3) is sent to the dust collector (2) through the air inlet (18) of the dust collector for dust removal. The exhaust gas from the dust collector (2) enters the circulating fan (1) through the exhaust port (19) of the dust collector. After being pressurized by the circulating fan (1), it is sent to the air inlet chambers of the high temperature discharge cooling device (12), the medium temperature discharge cooling device (13), and the low temperature discharge cooling device (14) respectively for cooling air circulation. Through air circulation and heat recycling, the waste heat contained in the exhaust gas is fully reused.

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