Boiler liquid slag waste heat recycling system based on coupling heat pump circulation

Abstract

The invention belongs to the technical field of liquid slagging boiler high-temperature slag waste heat utilization, and discloses a boiler liquid slag waste heat recycling system based on coupling heat pump circulation, which comprises a slag buffer module, a granulation module, a waste heat recycling module and a coupling heat pump waste heat utilization assembly, the granulating module is used for receiving the high-temperature liquid molten slag and granulating the high-temperature liquid molten slag into granulated slag; the waste heat recovery module absorbs slag waste heat in the granulation module with circulating water as a working medium, sequentially releases the absorbed slag waste heat to the absorption type heat pump module and the compression type heat pump module, returns the slag waste heat into the waste heat recovery module again, and recovers the slag waste heat of the granulation module as the working medium again. The compression type heat pump and the absorption type heat pump are used in a combined mode, and the centrifugal granulation technology is combined, so that efficient utilization of the liquid slag waste heat of the liquid slag discharging boiler is achieved, and therefore the ash heat loss of the liquid slag discharging boiler is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat utilization of high-temperature molten slag in a liquid slag discharge boiler, and in particular to a boiler liquid slag waste heat recovery and utilization system based on a coupled heat pump cycle. Background Art

[0002] Industrial energy consumption accounts for more than 70% of my country's total energy consumption. Industrial production consumes a large amount of fossil energy and generates a large amount of waste heat resources. Among them, in the power, steel, petrochemical and other industries, up to 20% to 50% of the waste heat is discharged or dissipated to the environment in different carriers, and the waste heat with flue gas as the medium accounts for up to 50% of the total waste heat resources. High-grade high-temperature flue gas waste heat has a high power recovery value. Reasonable and efficient recycling and utilization of this part of waste heat resources is an important part of industrial energy conservation and emission reduction. Liquid slag furnace, as a boiler form with high combustion intensity and low dust content in flue gas, has been favored in recent years, but because the ash of the liquid slag furnace is discharged in the form of high-temperature molten slag, the physical heat loss of the ash is very huge.

[0003] In order to solve the above technical problems, the main treatment methods for boiler liquid slag are divided into water quenching method and dry method. The water quenching method has a fast cooling rate and is easy to obtain slag particles with high glass content, but the liquid slag has a very high temperature, about 1400℃. When it encounters slag cooling water at about 25℃ and rapidly cools and granulates, it will release a large amount of heat, generate a large amount of water vapor and a large amount of slag water with a temperature of about 85-90℃. For a long time, this part of heat has not been reasonably utilized, but wasted in vain, and the large amount of water vapor and slag water generated will cause environmental thermal pollution after being discharged into the environment. Moreover, when the slag water is recycled, as the temperature of the circulating slag water gradually increases, it is bound to cause the liquid slag granulation rate to decrease, and the amount of coking in the granulation box will increase. In severe cases, it can cause slag blockage, causing the boiler to stop operating. Therefore, a large amount of new water has to be added to reduce the temperature of the circulating slag water, which will consume a large amount of water resources, especially for areas with water shortages, which will cause serious social harm. The dry process is to granulate the slag liquid first, and then recover the waste heat. According to the different granulation methods, it can be divided into mechanical crushing, air quenching and centrifugal granulation technology. Among them, centrifugal granulation combined with moving bed waste heat recovery technology does not consume water, has low energy consumption, obtains slag particles of small size and high quality, has a fast cooling rate, and has a high waste heat recovery rate. It is the preferred solution for liquid high-temperature slag treatment. However, in order to obtain further application in industrial production, three technical difficulties must still be solved, namely, the slag composition is complex, the temperature is high, the physical properties change greatly, and the granulation process is complex; the phase change particles coupled with the evolution of mineral phases are difficult to describe the non-steady-state composite heat exchange process under complex conditions; and the granulation-waste heat recovery multi-phase, multi-parameter, and multi-process information transmission is difficult.

[0004] Heat pumps have attracted much attention as an efficient and clean energy device that can utilize high-quality thermal energy. They are mainly divided into two types: compression heat pumps and absorption heat pumps. Absorption heat pumps use a small amount of high-temperature heat and a large amount of low-temperature heat to produce medium-temperature heat energy, also known as heat-increasing heat pumps. Compression heat pumps use a large amount of medium-temperature heat and low-temperature heat to produce a small amount of high-temperature heat energy, also known as warming heat pumps. Although absorption heat pumps consume very little electricity, due to the limitations of the thermal cycle, the COP of absorption heat pumps is relatively low. Although both can be used for waste heat recovery, due to their different operating temperatures, heating temperatures, and efficiencies, the application scope of these two types of heat pumps in the field of waste heat recovery is relatively small.

[0005] To this end, the present invention provides a boiler liquid slag waste heat recovery and utilization system based on a coupled heat pump cycle. Summary of the invention

[0006] In order to solve the above-mentioned deficiencies in the prior art and overcome the defect of low efficiency of waste heat utilization of liquid slag discharge boilers, the present invention provides a boiler liquid slag waste heat recovery and utilization system based on a coupled heat pump cycle. The present invention combines a compression heat pump with an absorption heat pump and combines centrifugal granulation technology to achieve efficient utilization of the waste heat of liquid slag in the liquid slag discharge furnace, thereby reducing the heat loss of ash slag in the liquid slag discharge boiler.

[0007] The boiler liquid slag waste heat recovery and utilization system based on coupled heat pump cycle of the present invention is realized by the following technical scheme:

[0008] The invention provides a boiler liquid slag waste heat recovery and utilization system based on a coupled heat pump cycle, comprising a molten slag buffer module, a granulation module, a waste heat recovery module and a coupled heat pump waste heat utilization component.

[0009] It should be noted that the slag buffer module is used to receive high-temperature liquid slag and temporarily store the high-temperature liquid slag.

[0010] The input end of the granulation module is connected to the output end of the slag buffer module to receive the high-temperature liquid slag output by the slag buffer module and granulate the slag into granulated slag.

[0011] The input end of the waste heat recovery module is connected to the output end of the granulation module, and circulating water is used as a working medium to absorb the waste heat of the slag in the granulation module.

[0012] The coupled heat pump waste heat utilization component includes an absorption heat pump module and a compression heat pump module connected in series. The working fluid input end of the absorption heat pump module is connected to the working fluid output end of the waste heat recovery module to receive circulating water that absorbs slag waste heat, and absorb and utilize a portion of the slag waste heat in the circulating water. The working fluid input end of the compression heat pump module is connected to the working fluid output end of the absorption heat pump module to absorb and utilize the remaining slag waste heat in the circulating water.

[0013] The working fluid output end of the compression heat pump module is connected to the working fluid input end of the waste heat recovery module, so that the circulating water after the heat is released in the coupled heat pump waste heat utilization component is returned to the waste heat recovery module and used as the working fluid to recover the slag waste heat of the granulation module.

[0014] In some feasible embodiments of the present invention, the absorption heat pump module is a lithium bromide absorption heat pump module.

[0015] In some feasible embodiments of the present invention, the absorption heat pump module includes a generator and a coupled heat exchanger, low-concentration lithium bromide is placed in the generator, and the working fluid input end of the generator is connected to the working fluid output end of the waste heat recovery module, so that a part of the slag waste heat in the circulating water heats the dilute lithium bromide solution, so that the water in the dilute lithium bromide solution is vaporized to form water vapor, and at the same time the concentration of lithium bromide is increased to obtain high-concentration lithium bromide; and the working fluid output end of the generator is connected to the working fluid output end of the compression heat pump module to release the remaining slag waste heat in the circulating water to the compression heat pump module.

[0016] In some feasible embodiments of the present invention, the absorption heat pump module further includes a condenser, a water vapor compressor, an absorber and a solution heat exchanger. The input end of the condenser is connected to the water vapor outlet of the generator to receive water vapor and condense it into refrigerant water. The input end of the coupling heat exchanger is connected to the output end of the condenser to receive refrigerant water and perform heat exchange in the coupling heat exchanger to form water vapor.

[0017] In some feasible embodiments of the present invention, the input end of the water vapor compressor is connected to the output end of the coupled heat exchanger to receive the water vapor after heat exchange and compress it into liquid water. High-concentration lithium bromide is placed in the absorber, and its input end is connected to the output end of the water vapor compressor to receive liquid water to dilute the high-concentration lithium bromide to form low-concentration lithium bromide. At the same time, the liquid water mixes with the lithium bromide concentrated solution in the absorber to release a large amount of heat. The output end of the generator and the output end of the absorber are both connected to the solution heat exchanger, and the high-concentration lithium bromide from the generator and the low-concentration lithium bromide from the absorber exchange heat in the solution heat exchanger, thereby forming a closed cycle.

[0018] In some feasible embodiments of the present invention, the absorption heat pump module also includes a water pump, and the water pump is arranged at the water outlet of the condenser, and the output end of the water pump is connected to the input end of the coupled heat exchanger to pump the condensed water into the coupled heat exchanger for heat exchange to form water vapor.

[0019] In some feasible embodiments of the present invention, the compression heat pump module includes an evaporator and a compressor; liquid Freon is placed in the evaporator, and the working fluid input end of the evaporator is connected to the working fluid output end of the generator, so that the remaining part of the slag waste heat in the circulating water is absorbed to heat the liquid Freon to form Freon vapor. The input end of the compressor is connected to the output end of the evaporator, and the output end of the compressor is connected to the input end of the coupling heat exchanger, so that the Freon vapor is transported to the coupling heat exchanger through the compressor to release the heat to the liquid water, and the heat is converted back into liquid Freon after the release. The input end of the evaporator is connected to the output end of the coupling heat exchanger, so that the liquid Freon is transported to the evaporator and reused as the working fluid in the compression heat pump module.

[0020] In some feasible embodiments of the present invention, the compression heat pump module also includes a throttle valve, and the input end of the throttle valve is connected to the output end of the coupled heat exchanger, and the output end of the throttle valve is connected to the input end of the evaporator, so as to control and adjust the flow rate of liquid Freon when it is delivered to the evaporator through the throttle valve.

[0021] In some feasible embodiments of the present invention, the absorber and the condenser are both provided with a condensate return water transmission line. The condensate return water input end of the absorber is used to connect the condensate return water of the steam turbine to receive the heat generated by the condensate return water when the high concentration of lithium bromide in the absorber is mixed with liquid water in the absorber, so as to achieve heating of the condensate return water. The condensate return water input end of the condenser is connected to the condensate return water output end of the absorber, and the condensate return water output end of the condenser is connected to the economizer of the boiler to receive the condensate return water heated by the absorber, and further heat it in the condenser, so as to achieve two-stage heating of the condensate return water, fully realize the utilization of waste heat, and the condensate return water after two-stage heating can be used as boiler feed water to re-enter the economizer for use.

[0022] In some feasible embodiments of the present invention, a flow control module is further provided between the slag buffer module and the granulation module, and the flow control module is used to control the flow rate and speed of the slag falling into the granulation module.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The liquid slag dry centrifugal granulation and waste heat recovery system of the present invention comprises a slag buffer module, a granulation module, a waste heat recovery module and a coupled heat pump waste heat utilization component. The granulation module receives the high-temperature liquid slag output by the slag buffer module and granulates it to form granulated slag, and the input end of the waste heat recovery module is connected to the output end of the granulation module, and the circulating water is used as the working medium to absorb the slag waste heat in the granulation module.

[0025] The present invention uses circulating water as a working medium to absorb the slag waste heat in the granulation module, and the absorbed slag waste heat is cooled once in the absorption heat pump module, and then enters the compression heat pump module to complete a secondary cooling. The circulating water after the secondary cooling is returned to the waste heat recovery module and is used as a working medium to recover the slag waste heat in the granulation module. The recycling and utilization of slag waste heat is achieved through circulating water.

[0026] The present invention adopts an absorption heat pump module and a compression heat pump module to form a coupled heat pump waste heat utilization component to jointly realize the utilization of slag waste heat, wherein the high heating temperature of the absorption heat pump is used to produce high-temperature hot water, and the compression cycle is used to increase the evaporation temperature of the absorption cycle to ensure the density difference of the absorption heat pump lithium bromide solution, thereby improving the performance of the unit.

[0027] The absorption heat pump module of the present invention heats the low-concentration lithium bromide solution by absorbing a part of the residual heat of the slag to generate water vapor, which enters the condenser and is condensed into refrigerant water by the steam turbine. The refrigerant water enters the evaporator and is reheated and evaporated into refrigerant steam by the compressed circulating Freon. The refrigerant steam at the outlet of the condenser evaporator is compressed by the compressor and then enters the absorber and mixes with the lithium bromide concentrated solution to release a large amount of heat to heat the steam turbine condensation return water.

[0028] The present invention also transmits the condensed return water from the turbine to the absorption cycle generator and the compression cycle evaporator for two-stage heating, and then uses the condensed return water after the two-stage heating as boiler feed water to enter the economizer, thereby realizing further utilization of the heat generated by the coupled heat pump waste heat utilization component. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a boiler liquid slag waste heat recovery system based on a coupled heat pump cycle in Example 1.

[0030] Figure 2 It is a structural schematic diagram of a boiler liquid slag waste heat recovery system based on a coupled heat pump cycle according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0032] The present invention takes into account the optimization strategy of multi-coal blending in coal-fired power plant boilers based on process factors, fully considers the requirements of the entire process of fuel procurement, blending and combustion in coal-fired power plant boilers, and utilizes the method of coupled heat pump circulation to utilize the waste heat of the liquid slag furnace of the power plant, giving full play to the advantages of low power consumption and high efficiency of the coupled heat pump circulation to achieve the purpose of utilizing the waste heat of the liquid slag furnace of the power plant.

[0033] Example 1

[0034] See also Figure 1 , this embodiment provides a boiler liquid slag waste heat recovery and utilization system based on a coupled heat pump cycle.

[0035] The boiler liquid slag waste heat recovery and utilization system based on the coupled heat pump cycle of this embodiment includes a slag buffer module 1, a granulation module 2, a waste heat recovery module and a coupled heat pump waste heat utilization component 3.

[0036] In this embodiment, the input end of the granulation module 2 is connected to the output end of the slag buffer module 1 to receive the high-temperature liquid slag output by the slag buffer module 1 and granulate it into granulated slag.

[0037] The input end of the waste heat recovery module is connected to the output end of the granulation module 2. The waste heat recovery module uses circulating water as a working medium to absorb the slag waste heat in the granulation module 2. Figure 1 The circulating water delivery route can be seen in the figure.

[0038] The coupled heat pump waste heat utilization component 3 is used to receive the slag waste heat absorbed by the circulating water from the granulation module 2, and absorb and utilize the slag waste heat. Figure 1 It can be seen that the coupled heat pump waste heat utilization assembly 3 of this embodiment includes an absorption heat pump module 31 and a compression heat pump module 32 which are connected in series in sequence.

[0039] Among them, Figure 1 As shown, the working fluid input end of the absorption heat pump module 31 of this embodiment is connected to the working fluid output end of the waste heat recovery module to receive the circulating water that absorbs the slag waste heat, and absorb and utilize a part of the slag waste heat in the circulating water. The working fluid input end of the compression heat pump module 32 is connected to the working fluid output end of the absorption heat pump module 31 to absorb and utilize the remaining slag waste heat in the circulating water.

[0040] like Figure 1 As shown, the working fluid output end of the compression heat pump module 32 of this embodiment is connected to the working fluid input end of the waste heat recovery module to return the circulating water after the heat is released in the coupled heat pump waste heat utilization component 3 to the waste heat recovery module, so as to realize the reuse of the circulating water as a working fluid and continue to recover the slag waste heat of the granulation module 2.

[0041] like Figure 2 As shown, in a preferred embodiment of the present invention, the absorption heat pump module 31 is a lithium bromide absorption heat pump module. That is, the absorption heat pump module 31 of this embodiment includes a generator 311 and a coupling heat exchanger 312 .

[0042] Low-concentration lithium bromide is placed in the generator 311 of this embodiment. The working fluid input end of the generator 311 is connected to the working fluid output end of the waste heat recovery module, so that a part of the slag waste heat in the circulating water heats the dilute lithium bromide solution, so that the water in the dilute lithium bromide solution is vaporized to form water vapor. At the same time, the concentration of lithium bromide is increased to obtain high-concentration lithium bromide.

[0043] The working fluid output end of the generator 311 of this embodiment is connected to the working fluid output end of the compression heat pump module 32 to release the remaining slag waste heat in the circulating water to the compression heat pump module 32, so that the slag waste heat can be further utilized by the compression heat pump module 32 later.

[0044] like Figure 2 As shown, in another preferred embodiment of the present invention, the absorption heat pump module 31 further includes a condenser 313 , a water vapor compressor 314 , an absorber 315 and a solution heat exchanger 316 .

[0045] The input end of the condenser 313 of this embodiment is connected to the water vapor outlet of the generator 311 to receive the water vapor and condense it into refrigerant water.

[0046] The input end of the coupling heat exchanger 312 of this embodiment is connected to the output end of the condenser 313 to receive refrigerant water and perform heat exchange in the coupling heat exchanger 312 to form water vapor.

[0047] The input end of the water vapor compressor 314 of this embodiment is connected to the output end of the coupling heat exchanger 312 to receive the water vapor after heat exchange and compress it into liquid water.

[0048] High-concentration lithium bromide is placed in the absorber 315 of this embodiment, and the input end of the absorber 315 is connected to the output end of the water vapor compressor 314 to receive liquid water to dilute the high-concentration lithium bromide to form low-concentration lithium bromide. At the same time, the liquid water mixes with the concentrated lithium bromide solution in the absorber 315 to release a large amount of heat.

[0049] The output end of the generator 311 and the output end of the absorber 315 of this embodiment are both connected to the solution heat exchanger 316, and the high-concentration lithium bromide from the generator 311 and the low-concentration lithium bromide from the absorber 315 exchange heat in the solution heat exchanger 316, thereby forming a closed cycle.

[0050] In another preferred embodiment of the present invention, the absorption heat pump module 31 further includes a water pump 317. Figure 2 As shown, the water pump 317 is arranged at the water outlet of the condenser 313, and the output end of the water pump 317 is connected to the input end of the coupled heat exchanger 312, so that the condensed water is pumped out through the water pump 317 to the coupled heat exchanger 312 for heat exchange to form water vapor.

[0051] like Figure 2 As shown, in a preferred embodiment of the present invention, the compression heat pump module 32 includes an evaporator 321 and a compressor 322 .

[0052] Liquid Freon is placed in the evaporator 321 of this embodiment, and the working fluid input end of the evaporator 321 is connected to the working fluid output end of the generator 311, so that the residual heat of the slag remaining in the circulating water can be absorbed to heat the liquid Freon to form Freon vapor.

[0053] The input end of the compressor 322 is connected to the output end of the evaporator 321, and the output end of the compressor 322 is connected to the input end of the coupling heat exchanger 312, so that the Freon vapor is transported to the coupling heat exchanger 312 through the compressor 322 to release the heat to the liquid water, and the heat is converted back into liquid Freon after the release. The input end of the evaporator 321 is connected to the output end of the coupling heat exchanger 312, so that the liquid Freon is transported to the evaporator 321 and reused as the working fluid in the compression heat pump module 32.

[0054] like Figure 2 As shown, in a preferred embodiment of the present invention, the compression heat pump module 32 further includes a throttle valve 323. The input end of the throttle valve 323 of this embodiment is connected to the output end of the coupling heat exchanger 312, and the output end of the throttle valve 323 is connected to the input end of the evaporator 321, so that the flow rate of the liquid Freon when being delivered to the evaporator 321 is controlled and adjusted by the throttle valve 323.

[0055] like Figure 2 As shown, in a preferred embodiment of the present invention, the absorber 315 and the condenser 313 are both provided with a condensate return water transmission line.

[0056] The condensate return water input end of the absorber 315 of this embodiment is used to connect the condensate return water of the turbine to receive the heat generated by the condensate return water when the high concentration lithium bromide and liquid water in the absorber 315 are mixed in the absorber 315, so as to heat the condensate return water.

[0057] The condensate return water input end of the condenser 313 of this embodiment is connected to the condensate return water output end of the absorber 315, and the condensate return water output end of the condenser 313 is connected to the economizer of the boiler, so as to receive the condensate return water heated by the absorber 315, and further heat it in the condenser 313 to obtain two-stage heated condensate return water, and the two-stage heated condensate return water is used as boiler feed water to enter the economizer for use.

[0058] like Figure 2As shown, in a preferred embodiment of the present invention, a flow control module 4 is further provided between the slag buffer module 1 and the granulation module 2 , and the flow control module 4 is used to control the flow rate and speed of the slag falling into the granulation module 2 .

[0059] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A boiler liquid slag waste heat recovery system based on coupled heat pump cycle, characterized in that: It comprises a slag buffer module (1), a granulation module (2), a waste heat recovery module and a coupled heat pump waste heat utilization component (3); The input end of the granulation module (2) is connected to the output end of the slag buffer module (1) to receive the high-temperature liquid slag output by the slag buffer module (1) and granulate the slag to form granulated slag; The input end of the waste heat recovery module is connected to the output end of the granulation module (2), and circulating water is used as a working medium to absorb the waste heat of the slag in the granulation module (2); The coupled heat pump waste heat utilization component (3) comprises an absorption heat pump module (31) and a compression heat pump module (32) which are sequentially connected in series; The working fluid input end of the absorption heat pump module (31) is connected to the working fluid output end of the waste heat recovery module to absorb and utilize a portion of the slag waste heat in the circulating water; The working fluid input end of the compression heat pump module (32) is connected to the working fluid output end of the absorption heat pump module (31) to absorb and utilize the residual heat of the slag remaining in the circulating water; the working fluid output end of the compression heat pump module (32) is connected to the working fluid input end of the residual heat recovery module to return the circulating water after the heat is released in the coupled heat pump residual heat utilization component (3) to the residual heat recovery module, and to be used as the working fluid to recover the residual heat of the slag in the granulation module (2).

2. The boiler liquid slag waste heat recovery and utilization system based on coupled heat pump cycle according to claim 1 is characterized in that: The absorption heat pump module (31) is a lithium bromide absorption heat pump module.

3. The boiler liquid slag waste heat recovery system based on coupled heat pump cycle according to claim 2 is characterized in that: The absorption heat pump module (31) comprises a generator (311) and a coupled heat exchanger (312), wherein low-concentration lithium bromide is placed in the generator (311), and the working fluid input end of the generator (311) is connected to the working fluid output end of the waste heat recovery module, so that a portion of the slag waste heat in the circulating water is released to the low-concentration lithium bromide in the generator (311); and the working fluid output end of the generator (311) is connected to the working fluid output end of the compression heat pump module (32), so that the remaining slag waste heat in the circulating water is released to the compression heat pump module (32).

4. The boiler liquid slag waste heat recovery and utilization system based on coupled heat pump cycle according to claim 3 is characterized in that: The absorption heat pump module (31) further comprises a condenser (313), a water vapor compressor (314), an absorber (315) and a solution heat exchanger (316); The input end of the condenser (313) is in communication with the water vapor outlet of the generator (311) so as to receive the water vapor and condense it into refrigerant water; The input end of the coupled heat exchanger (312) is in communication with the output end of the condenser (313) to receive refrigerant water and allow the refrigerant water to undergo heat exchange in the coupled heat exchanger (312) to form water vapor; The input end of the water vapor compressor (314) is in communication with the output end of the coupled heat exchanger (312) to receive the water vapor after heat exchange and compress it into liquid water; The absorber (315) contains high-concentration lithium bromide, and its input end is connected to the output end of the water vapor compressor (314) to receive liquid water; The output end of the generator (311) and the output end of the absorber (315) are both connected to the solution heat exchanger (316).

5. The boiler liquid slag waste heat recovery system based on coupled heat pump cycle according to claim 4 is characterized in that: The absorption heat pump module (31) further comprises a water pump (317), wherein the water pump (317) is arranged at the water outlet of the condenser (313), and the output end of the water pump (317) is connected to the input end of the coupling heat exchanger (312).

6. The boiler liquid slag waste heat recovery system based on coupled heat pump cycle according to claim 3 is characterized in that: The compression heat pump module (32) comprises an evaporator (321) and a compressor (322); Liquid Freon is placed in the evaporator (321), and the working medium input end of the evaporator (321) is connected to the working medium output end of the generator (311), so that the residual heat of the slag remaining in the circulating water is absorbed to heat the liquid Freon to form Freon vapor; The input end of the compressor (322) is in communication with the output end of the evaporator (321), and the output end of the compressor (322) is in communication with the input end of the coupled heat exchanger (312), so that the Freon vapor is transported to the coupled heat exchanger (312) through the compressor (322) to release heat to liquid water and then be converted back into liquid Freon; The input end of the evaporator (321) is connected to the output end of the coupled heat exchanger (312) so as to transport the liquid Freon to the evaporator (321) and reuse it as a working fluid.

7. The boiler liquid slag waste heat recovery system based on coupled heat pump cycle according to claim 6 is characterized in that: The compression heat pump module (32) further comprises a throttle valve (323), wherein the input end of the throttle valve (323) is connected to the output end of the coupled heat exchanger (312), and the output end of the throttle valve (323) is connected to the input end of the evaporator (321).

8. The boiler liquid slag waste heat recovery system based on coupled heat pump cycle according to claim 4 is characterized in that: The absorber (315) and the condenser (313) are both provided with a condensate return water transmission line; The condensed return water input end of the absorber (315) is in communication with the condensed return water of the steam turbine, so that the condensed return water absorbs heat in the absorber (315), thereby heating the condensed return water; The condensate return water input end of the condenser (313) is connected to the condensate return water output end of the absorber (315), and the condensate return water output end of the condenser (313) is connected to the economizer of the boiler.

9. The boiler liquid slag waste heat recovery system based on coupled heat pump cycle according to claim 1, characterized in that: A flow control module (4) is also provided between the slag buffer module (1) and the granulation module (2).

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