Heat supply system with waste heat utilization of heat engine unit coupled with two-stage compression heat pump by spraying method

Abstract

The application discloses a heat supply system for waste heat utilization of a heat and power unit coupled with a two-stage compression heat pump by a spraying method, which comprises a low-temperature loop of an internal circulating working medium side of a two-stage compression heat pump unit connected with a spraying tower, a medium-temperature loop of the internal circulating working medium side of the two-stage compression heat pump unit connected with a desulfurization tower, a flue gas outlet of the desulfurization tower connected with a flue gas inlet of the spraying tower, and a water side of the two-stage compression heat pump unit connected with a primary network circulating water supply and return system. The system sprays and cools saturated flue gas at the outlet of the desulfurization tower through the spraying tower, so that water vapor is condensed and releases heat, and then two-stage waste heat sources are recycled and utilized. The spraying water waste heat is recycled by a low-temperature loop of a two-stage compression heat pump, and the desulfurization slurry waste heat is recycled by a medium-temperature loop of a two-stage compression heat pump. The flue gas waste heat is fully recycled, the two-stage compressor is used for compression and temperature rise, the power consumption of the compressor is reduced, the COP of the heat pump is improved, and more heating capacity is obtained under the same power consumption.

Description

Technical Field

[0001] This invention belongs to the field of waste heat utilization technology of thermal power units, and particularly relates to a waste heat utilization heating system for thermal power units using a spray method coupled with a two-stage compression heat pump. Background Technology

[0002] Energy is the material foundation and a crucial driving force for economic and social development. The main direction of medium- and long-term energy development is energy electrification, which is also the best way to promote the green and low-carbon transformation of the energy structure. In building an environmentally friendly and resource-saving society, to create a sustainable energy mechanism, promote low-carbon and green industrial electrification, and advance ecological civilization, it is essential to address the challenges posed by NOx. x CO2, SO x The total emissions and concentrations of pollutants, primarily dust, are a major concern. These pollutants mainly originate from the combustion of fossil fuels, primarily coal. Coal-fired power generating units, as major coal consumers, have received significant attention from all sectors of society. Currently, adjusting the coal-dominated energy structure and building a clean, low-carbon, safe, and efficient energy system has become the development direction of power system structural reform. In the current environment of rapid growth in wind and solar renewable energy capacity, coal-fired combined heat and power (CHP) units, as the main heat source for centralized heating in northern regions, face immense pressure during the heating season for peak shaving and heating supply. On one hand, there is the increasing residential heating load due to urban expansion; on the other hand, there is the increasing demand for deep peak shaving from coal-fired power generating units due to the rising electricity from renewable energy sources. Limited by the unit's extraction capacity and parameters, coal-fired CHP units have strong thermoelectric coupling, resulting in limited deep peak shaving capacity while handling high heat loads. Currently, most units handling high heat loads cannot meet the extremely low peak shaving requirements of the power grid. Faced with dual pressures, improving energy efficiency is a cost-effective and efficient means of transformation that can meet both peak-shaving heating needs and energy conservation and carbon reduction policies. Currently, the utilization of waste heat from the cold end of steam turbines has been fully developed, but the utilization of waste heat from boiler exhaust has not been fully developed. The temperature of exhaust gas at the tail end is mostly above 60°C. This part of the exhaust gas is still saturated after passing through the desulfurization tower, and it contains a large amount of low-grade water vapor latent heat. How to heat and utilize this heat to increase the unit's heating capacity, thereby improving the unit's thermal efficiency and peak-shaving capacity, is currently a key area for breakthrough. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention aims to provide a waste heat utilization heating system for cogeneration units using a spray method coupled with a two-stage compression heat pump. This system solves the problem of insufficient heating and peak-shaving capacity of conventional coal-fired cogeneration units in northern regions, effectively improving the heating and utilization of waste heat from boiler exhaust and increasing the unit's heating capacity, thereby improving the unit's thermal efficiency and peak-shaving capacity.

[0004] This invention is achieved through the following technical solution:

[0005] A waste heat recovery heating system for a thermoelectric unit using a spray-type coupled two-stage compression heat pump includes,

[0006] A primary circulating water supply and return system, a two-stage compression heat pump unit, a spray tower, and a desulfurization tower.

[0007] The low-temperature loop of the internal circulating working fluid side of the dual-stage compression heat pump unit is connected to the spray tower, and the medium-temperature loop of the internal circulating working fluid side of the dual-stage compression heat pump unit is connected to the desulfurization tower; the flue gas outlet of the desulfurization tower is connected to the flue gas inlet of the spray tower; the water side of the dual-stage compression heat pump unit is connected to the primary network circulating water supply and return system.

[0008] Preferably, the two-stage compression heat pump unit includes a condenser, an intermediate heat exchanger, a high-pressure stage compressor, an evaporator, and a low-pressure stage compressor; the desulfurization slurry side of the desulfurization tower is connected to the working fluid side of the intermediate heat exchanger; and the spray water side of the spray tower is connected to the water side of the evaporator.

[0009] The water side of the condenser is connected to the primary network circulating water supply and return system; the working fluid side of the condenser is divided into two paths, one of which is a medium-temperature loop and the other is a low-temperature loop; the outlet of the medium-temperature branch of the working fluid side of the condenser is connected to the intermediate heat exchanger, the high-pressure stage compressor and the working fluid side inlet of the condenser to form a medium-temperature loop; the outlet of the low-temperature branch of the working fluid side of the condenser is connected to the working fluid side of the evaporator and the low-pressure stage compressor, and then merges with the medium-temperature loop before connecting to the working fluid side inlet of the condenser through the high-pressure stage compressor to form a low-temperature loop; an intermediate working fluid heat exchanger is provided between the medium-temperature loop and the low-temperature loop.

[0010] Preferably, a slurry spraying pump is installed on the pipeline between the desulfurization slurry outlet side of the desulfurization tower and the working fluid inlet side of the intermediate heat exchanger, and a slurry nozzle is installed on the desulfurization slurry inlet pipeline inside the desulfurization tower.

[0011] Preferably, a spray water pump is installed on the pipeline between the spray water side outlet of the spray tower and the water side inlet of the evaporator, and a spray nozzle is installed on the spray water inlet pipeline inside the spray tower.

[0012] Preferably, a first expansion valve is provided on the outlet pipe of the medium-temperature branch on the working fluid side of the condenser; and a second expansion valve is provided on the outlet pipe of the low-temperature branch on the working fluid side of the condenser.

[0013] Preferably, a condensate return pump is provided between the spray tower and the desulfurization tower.

[0014] Preferably, the primary network return water pipeline of the primary network circulating water system is equipped with a heating network circulating water pump, the water-side inlet of the condenser is connected to the primary network return water pipeline, and the water-side outlet of the condenser is connected to the primary network supply water pipeline of the primary network circulating water system.

[0015] Preferably, the water-side inlet and water-side outlet of the condenser are connected by a branch pipeline; the branch pipeline is equipped with a ball valve, an electric regulating valve and a first check valve.

[0016] Preferably, a heating network heater is provided between the water-side outlet of the condenser and the primary network water supply pipeline; the water-side inlet of the heating network heater is connected to the water-side outlet of the condenser, and the water-side outlet of the heating network heater is connected to the primary network water supply pipeline; the steam-side inlet of the heating network heater is connected to the heating steam extraction; and the steam-side outlet of the heating network heater is connected to the deaerator.

[0017] Preferably, a second check valve is provided on the steam-side inlet pipe of the heating network heater, and a heating network drain pump is provided on the steam-side outlet pipe of the heating network heater.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] This invention provides a waste heat utilization heating system for cogeneration units using a spray-type coupled two-stage compression heat pump. Addressing the problem of insufficient peak-shaving capacity of conventional coal-fired cogeneration units in northern regions, this invention establishes a waste heat cascade utilization heating system using a novel two-stage compression heat pump coupled with a spray-type flue gas waste heat recovery tower. This system involves installing a new spray tower after the desulfurization tower to further cool the saturated flue gas at the desulfurization tower outlet, taking advantage of the characteristic that the saturated moisture content of the flue gas decreases with decreasing temperature. This causes the water vapor in the flue gas to condense and release heat. Since the temperature of the desulfurization slurry is higher than that of the spray water, in order to improve energy utilization, the two-stage waste heat sources are recovered and utilized in stages. A two-stage compression heat pump low-temperature loop is used to recover the waste heat of the spray water, and a two-stage compression heat pump medium-temperature loop is used to recover the waste heat of the desulfurization slurry. While fully recovering the waste heat of the flue gas, a two-stage compressor is used to compress and heat the gas, reducing compressor power consumption and improving the heat pump COP. This allows for obtaining more heating capacity with the same power consumption, or reducing the power consumption of the heat pump under the same heat pump load, enabling the unit to obtain greater heating capacity or better economy, while improving the overall thermal efficiency of the unit. A two-stage compression heat pump and a heating network heater are used together as the heat source for the circulating water of the heating network, which is heated in stages to ensure the amount of waste heat recovery and energy utilization. Finally, high-grade heating steam is added to ensure the heating temperature and heat supply for users, reduce the unit's heating and power generation costs, and achieve the goal of energy conservation and carbon reduction while meeting peak-shaving heating needs.

[0020] Furthermore, this invention utilizes a spraying method to cool the flue gas at the outlet of the desulfurization tower, which can recover a large amount of latent heat contained in the water vapor in the tail flue gas. The condensate will be sent to the desulfurization tower to compensate for the large amount of water loss caused during the spraying of the desulfurization slurry and reduce the water consumption of the unit.

[0021] Furthermore, this invention utilizes a two-stage compression heat pump to utilize the low-grade waste heat contained in the desulfurization slurry and spray water in a cascade manner, indirectly and fully recovering the waste heat of the flue gas, improving energy utilization efficiency. At the same time, the two-stage compressor can reduce power consumption, increase the COP of the heat pump, and improve economic efficiency.

[0022] Furthermore, this invention uses a two-stage compression heat pump coupled with a spray-type waste heat recovery system as the basic heat source for coal-fired cogeneration units to heat the circulating water of the heating network in stages. First, the heat pump is used to perform primary heating of the return water of the heating network, and then the heating network heater is used to perform peak heating of the heating network water. By using waste heat utilization and heating network water in stages, the energy utilization rate is improved, the heating economy is improved, and the coal consumption and pollutant emissions are reduced.

[0023] Furthermore, by using a waste heat recovery heat pump to participate in heating, this invention reduces the steam extraction load for heating of the unit itself, improves the unit's heating capacity, and at the same time, the heat pump consumes a portion of the power generation during the heating process, which further improves the unit's deep peak-shaving capacity and enhances the flexibility of peak-shaving heating. Attached Figure Description

[0024] Figure 1 A schematic diagram of a waste heat utilization heating system for a thermal power unit coupled with a two-stage compression heat pump using a spray method.

[0025] In the diagram: 1-Heating network circulating water pump; 2-Condenser; 3-Ball valve; 4-Electric regulating valve; 5-First check valve; 6-Heating network heater; 7-Second check valve; 8-Heating network drain pump; 9-First expansion valve; 10-Intermediate working fluid heat exchanger; 11-Intermediate heat exchanger; 12-High-pressure stage compressor; 13-Second expansion valve; 14-Evaporator; 15-Low-pressure stage compressor; 16-Desulfurization tower; 17-Slurry nozzle; 18-Spray tower; 19-Spray nozzle; 20-Condensate return pump; 21-Slurry spray pump; 22-Spray water pump. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] This invention aims to provide a waste heat utilization heating system for cogeneration units using a spray-type coupled two-stage compression heat pump. Addressing the problem of insufficient peak-shaving capacity of conventional coal-fired cogeneration units in northern regions, this invention establishes a waste heat cascade utilization heating system using a novel two-stage compression heat pump coupled with a spray-type flue gas waste heat recovery tower. This system involves installing a new spray tower after the desulfurization tower to further cool the saturated flue gas at the desulfurization tower outlet, taking advantage of the characteristic that the saturated moisture content of the flue gas decreases with decreasing temperature. This causes the water vapor in the flue gas to condense and release heat. Since the temperature of the desulfurization slurry is higher than that of the spray water, in order to improve energy utilization, the two-stage waste heat sources are recovered and utilized in stages. A two-stage compression heat pump low-temperature loop is used to recover the waste heat of the spray water, and a two-stage compression heat pump medium-temperature loop is used to recover the waste heat of the desulfurization slurry. While fully recovering the waste heat of the flue gas, a two-stage compressor is used to compress and heat the gas, reducing compressor power consumption and improving the heat pump COP. This allows for obtaining more heating capacity with the same power consumption, or reducing the power consumption of the heat pump under the same heat pump load, enabling the unit to obtain greater heating capacity or better economy, while improving the overall thermal efficiency of the unit. A two-stage compression heat pump and a heating network heater are used together as the heat source for the circulating water of the heating network, which is heated in stages to ensure the amount of waste heat recovery and energy utilization. Finally, high-grade heating steam is added to ensure the heating temperature and heat supply for users, reduce the unit's heating and power generation costs, and achieve the goal of energy conservation and carbon reduction while meeting peak-shaving heating needs.

[0029] like Figure 1 As shown, it includes a primary network circulating water supply and return system, a two-stage compression heat pump unit, a spray tower 18, and a desulfurization tower 16.

[0030] The low-temperature loop of the internal circulating working fluid side of the dual-stage compression heat pump unit is connected to the spray tower 18, and the medium-temperature loop of the internal circulating working fluid side of the dual-stage compression heat pump unit is connected to the desulfurization tower 16; the flue gas outlet of the desulfurization tower 16 is connected to the flue gas inlet of the spray tower 18; the water side of the dual-stage compression heat pump unit is connected to the primary network circulating water supply and return system; by using the spray method to cool the flue gas at the outlet of the desulfurization tower, a large amount of latent heat contained in the water vapor in the tail flue gas can be recovered, and the condensate will be sent to the desulfurization tower to make up for the large amount of water loss caused during the spraying of the desulfurization slurry and reduce the water consumption of the unit; by using the dual-stage compression heat pump to utilize the low-grade waste heat contained in the desulfurization slurry and spray water in a cascade manner, the waste heat of the flue gas can be recovered indirectly and fully, improving the energy utilization rate. At the same time, the dual-stage compressor can reduce power consumption, improve the COP of the heat pump, and improve economic efficiency.

[0031] The two-stage compression heat pump unit includes a condenser 2, an intermediate heat exchanger 11, a high-pressure stage compressor 12, an evaporator 14, and a low-pressure stage compressor 15. The desulfurization slurry side of the desulfurization tower 16 is connected to the working fluid side of the intermediate heat exchanger 11; the spray water side of the spray tower 18 is connected to the water side of the evaporator 14.

[0032] The water side of the condenser 2 is connected to the primary network circulating water supply and return system; the working fluid side of the condenser 2 is divided into two paths, one of which is a medium-temperature loop and the other is a low-temperature loop; the outlet of the medium-temperature branch of the working fluid side of the condenser 2 is connected to the intermediate heat exchanger 11, the high-pressure stage compressor 12 and the working fluid side inlet of the condenser 2 to form a medium-temperature loop; the outlet of the low-temperature branch of the working fluid side of the condenser 2 is connected to the working fluid side of the evaporator 14 and the low-pressure stage compressor 15, and then merges with the medium-temperature loop and is connected to the working fluid side inlet of the condenser 2 through the high-pressure stage compressor 12 to form a low-temperature loop; an intermediate working fluid heat exchanger 10 is provided between the medium-temperature loop and the low-temperature loop. Using a two-stage compression heat pump coupled with a spray-type waste heat recovery system as the basic heat source for coal-fired cogeneration units, the circulating water of the heating network is heated in stages. First, the heat pump is used to perform primary heating of the return water of the heating network, and then the heating network heater is used to perform peak heating of the heating network water. By using waste heat utilization and heating network water in stages, the energy utilization rate is improved, the heating economy is improved, and the coal consumption and pollutant emissions are reduced.

[0033] A slurry spray pump 21 is installed on the pipeline between the desulfurization slurry outlet side of the desulfurization tower 16 and the working fluid inlet side of the intermediate heat exchanger 11, and a slurry nozzle 17 is installed on the desulfurization slurry inlet pipeline inside the desulfurization tower 16.

[0034] A spray water pump 22 is installed on the pipeline between the spray water side outlet of the spray tower 18 and the water side inlet of the evaporator 14, and a spray nozzle 19 is installed on the spray water inlet pipeline inside the spray tower 18.

[0035] A first expansion valve 9 is installed on the outlet pipe of the medium-temperature branch on the working fluid side of the condenser 2; a second expansion valve 16 is installed on the outlet pipe of the low-temperature branch on the working fluid side of the condenser 2.

[0036] A condensate return pump 20 is installed between the spray tower 18 and the desulfurization tower 16.

[0037] The primary network return water pipeline of the primary network circulating water system is equipped with a heating network circulating water pump 1. The water-side inlet of the condenser 2 is connected to the primary network return water pipeline, and the water-side outlet of the condenser 2 is connected through the primary network supply water pipeline of the primary network circulating water system.

[0038] The water-side inlet and water-side outlet of the condenser 2 are connected by a branch pipeline; a ball valve 3, an electric regulating valve 4 and a first check valve 5 are installed on the branch pipeline.

[0039] A heat network heater 6 is installed between the water-side outlet of the condenser 2 and the primary network water supply pipeline; the water-side inlet of the heat network heater 6 is connected to the water-side outlet of the condenser 2, and the water-side outlet of the heat network heater 6 is connected to the primary network water supply pipeline; the steam-side inlet of the heat network heater 6 is connected to the heating steam extraction; and the steam-side outlet of the heat network heater 6 is connected to the deaerator. After the waste heat recovery heat pump participates in the heating, the heating steam extraction load of the unit body is reduced, and the heating capacity of the unit is improved. At the same time, the heat pump consumes a part of the power generation during the heating process, which improves the deep peak-shaving capacity of the unit and further enhances the flexibility of peak-shaving heating.

[0040] The intermediate working fluid heat exchanger 10 is used for heat exchange between two working fluids at different temperatures inside the heat pump, while the intermediate heat exchanger 11 is used for heat exchange between the intermediate loop working fluid inside the heat pump and an external medium-temperature heat source.

[0041] A second check valve 7 is installed on the steam-side inlet pipe of the heat network heater 6, and a heat network drain pump 8 is installed on the steam-side outlet pipe of the heat network heater 6.

[0042] This invention establishes a waste heat cascade utilization heating system using a novel two-stage compression heat pump coupled with a spray-type flue gas waste heat recovery tower. The spray-type flue gas waste heat recovery tower utilizes the characteristic that the saturated moisture content of flue gas decreases with decreasing temperature. For the tail flue gas, which is already saturated with moisture after passing through the desulfurization tower, a spray tower is constructed to cool the tail flue gas with water, causing the water vapor to condense and release heat. The sprayed water, after being heated, serves as the low-temperature waste heat source for the low-temperature loop of the two-stage compression heat pump. After being heated by the low-temperature stage of the heat pump, it returns to the spray tower to continue spraying with the tail flue gas. The medium-temperature waste heat source for the medium-temperature loop of the heat pump is the desulfurization slurry in the desulfurization tower. A wide-channel intermediate heat exchanger is used to prevent the heat exchanger from becoming clogged during heat exchange between the desulfurization slurry and the heat pump working fluid. After being heated by spraying the flue gas, the desulfurization slurry is sent to the intermediate stage of the heat pump. The heat is raised and then sent back to the desulfurization tower to continue spraying the boiler outlet flue gas to desulfurize and cool it down. The two-stage compression heat pump divides the internal circulating working fluid into two paths: a medium-temperature loop and a low-temperature loop. The medium-temperature loop first depressurizes and then absorbs heat from the low-temperature loop, and then absorbs the waste heat of the desulfurization slurry through the medium-temperature heat exchanger. The low-temperature loop first exchanges heat and then absorbs the waste heat of the spray water in the evaporator. After being pressurized by the low-pressure stage compressor, it is mixed with the working fluid of the medium-temperature loop. The mixed working fluid is then pressurized by the high-pressure stage compressor and sent to the condenser to release heat to the heating network circulating water return water. The heating network circulating water return water passes through the heat pump condenser and the heating network heater in sequence. According to the principle of temperature matching and tiered utilization, the waste heat is first used to heat the heating network return water, and then the heating network circulating water is peak-heated using the heating extraction steam to meet the heating temperature required by users, thereby improving energy utilization efficiency.

[0043] The specific system operation mode is as follows:

[0044] like Figure 1As shown, in the waste heat utilization heating system of the thermal power unit coupled with a two-stage compression heat pump using the spray method, the return water of the heating network is pressurized by the heating network circulating water pump 1 and sent to the condenser 2 to be heated by the heat pump. Then, it is heated to the user's required water supply temperature by the condensation of the heating extraction steam in the heating network heater 6, and then supplied to the outside. The heating extraction steam is provided by the unit itself and enters the steam side of the heating network heater 6 after passing through the second check valve 7. The condensation of the resulting heating network condensate is sent back to the unit's regenerative system by the heating network condensate pump 8. The flue gas at the tail of the boiler is first sprayed and cooled by the desulfurization slurry in the desulfurization tower 16, and then the flue gas at the outlet of the desulfurization tower is sprayed and cooled by the spray tower 18 before finally being discharged into the atmosphere. The desulfurization slurry in the desulfurization tower 16 is heated by the spray. The liquid is pumped into the intermediate heat exchanger 11 by the slurry spray pump 21 to be heated, and then sprayed onto the flue gas at the boiler outlet by the slurry nozzle 17 to cool it down. The spray water in the spray tower 18, after being sprayed and heated, is pumped into the evaporator 14 by the spray water pump 22 to be heated, and then sprayed onto the flue gas at the outlet of the desulfurization tower 16 by the spray nozzle 19 to cool it down. The flue gas is finally discharged into the atmosphere from the outlet of the spray tower 18. In order to maintain the liquid level balance in the desulfurization tower 16, the liquid level in the spray tower 19 continuously rises and the liquid level in the desulfurization tower 16 continuously falls during operation. However, the amount of water recovered in the spray tower 18 is greater than the amount of water reduced in the desulfurization tower 16. Therefore, the condensate return pump 20 is used to ensure the dynamic balance of the liquid levels in the desulfurization tower 16 and the spray tower 18.

[0045] The two-stage compression heat pump consists of a condenser 2, a first expansion valve 9, an intermediate working fluid heat exchanger 10, an intermediate heat exchanger 11, a high-pressure stage compressor 12, a second expansion valve 13, an evaporator 14, and a low-pressure stage compressor 15. The internal working fluid condenses and releases heat in the condenser 2, heating the circulating water in the heating network. Afterward, the outlet is divided into two paths: one is the medium-temperature loop working fluid, which is depressurized by the first expansion valve 9 and then absorbs heat from the low-temperature loop working fluid through the intermediate working fluid heat exchanger 10, before absorbing waste heat from the desulfurization slurry through the intermediate heat exchanger 11; the other is the low-temperature loop working fluid, which is cooled by the intermediate working fluid heat exchanger 10 and then... The second expansion valve 13 reduces the pressure, and then the water enters the evaporator 14 to absorb the waste heat of the spray water. After being compressed by the low-pressure stage compressor, it is mixed with the working fluid in the medium-temperature loop. The mixed working fluid is then compressed by the high-pressure stage compressor 12 and sent back to the condenser 2. The heating network circulating water bypass, consisting of ball valve 3, electric regulating valve 4, first check valve 5 and bypass pipe, is used to regulate the amount of heating network circulating water entering the condenser 2. When all heating network return water needs to flow through the condenser 2, ball valve 3 is closed. When the condenser 2 only receives part of the heating network return water, ball valve 3 is opened, and the amount of heating network circulating water entering the condenser 2 is controlled by adjusting the opening of the electric regulating valve 4.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or it can be in a centered component. When a component is said to be "connected to" another component, it can be directly connected to the other component or it may also be in a centered component. When a component is said to be "set to" another component, it can be directly set on the other component or it may also be in a centered component.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A waste heat recovery heating system for a thermal power unit using a spray-type coupled two-stage compression heat pump, characterized in that, include, A primary network circulating water supply and return system, a two-stage compression heat pump unit, a spray tower (18) and a desulfurization tower (16). The low-temperature loop of the internal circulating working fluid side of the dual-stage compression heat pump unit is connected to the spray tower (18), and the medium-temperature loop of the internal circulating working fluid side of the dual-stage compression heat pump unit is connected to the desulfurization tower (16); the flue gas outlet of the desulfurization tower (16) is connected to the flue gas inlet of the spray tower (18); the water side of the dual-stage compression heat pump unit is connected to the primary network circulating water supply and return system; the boiler tail flue enters through the flue gas inlet side of the desulfurization tower (16), and then discharges the waste heat utilization flue gas through the flue gas outlet of the spray tower (18); The two-stage compression heat pump unit includes a condenser (2), an intermediate heat exchanger (11), a high-pressure stage compressor (12), an evaporator (14), and a low-pressure stage compressor (15). The desulfurization slurry side of the desulfurization tower (16) is connected to the working fluid side of the intermediate heat exchanger (11); the spray water side of the spray tower (18) is connected to the water side of the evaporator (14). The water side of the condenser (2) is connected to the primary network circulating water supply and return system; the working fluid side of the condenser (2) is divided into two paths, one of which is a medium-temperature loop and the other is a low-temperature loop; the outlet of the medium-temperature branch of the working fluid side of the condenser (2) is connected to the intermediate heat exchanger (11), the high-pressure stage compressor (12) and the working fluid side inlet of the condenser (2) to form a medium-temperature loop; the outlet of the low-temperature branch of the working fluid side of the condenser (2) is connected to the working fluid side of the evaporator (14) and the low-pressure stage compressor (15), and then merges with the medium-temperature loop and is connected to the working fluid side inlet of the condenser (2) through the high-pressure stage compressor (12) to form a low-temperature loop; an intermediate working fluid heat exchanger (10) is provided between the medium-temperature loop and the low-temperature loop. A first expansion valve (9) is installed on the outlet pipe of the medium-temperature branch on the working fluid side of the condenser (2); a second expansion valve (13) is installed on the outlet pipe of the low-temperature branch on the working fluid side of the condenser (2).

2. The waste heat utilization heating system of a thermal power unit with a spray-type coupled two-stage compression heat pump according to claim 1, characterized in that, A slurry spray pump (21) is installed on the pipeline between the desulfurization slurry outlet side of the desulfurization tower (16) and the working fluid inlet side of the intermediate heat exchanger (11), and a slurry nozzle (17) is installed on the desulfurization slurry inlet pipeline inside the desulfurization tower (16).

3. The waste heat utilization heating system of a thermal power unit with a spray-type coupled two-stage compression heat pump according to claim 1, characterized in that, A spray water pump (22) is installed on the pipeline between the spray water side outlet of the spray tower (18) and the water side inlet of the evaporator (14), and a spray nozzle (19) is installed on the spray water inlet pipeline inside the spray tower (18).

4. The waste heat utilization heating system of a thermal power unit with a spray-type coupled two-stage compression heat pump according to claim 1, characterized in that, A condensate return pump (20) is provided between the condensate side outlet of the spray tower (18) and the liquid side inlet of the desulfurization tower (16).

5. A waste heat utilization heating system for a thermal power unit using a spray-type coupled two-stage compression heat pump according to claim 1, characterized in that, The primary network return water pipeline of the primary network circulation water supply and return system is equipped with a heating network circulation water pump (1), the water-side inlet of the condenser (2) is connected to the primary network return water pipeline, and the water-side outlet of the condenser (2) is connected to the primary network supply water pipeline of the primary network circulation water system.

6. A waste heat recovery heating system for a thermal power unit using a spray-type coupled two-stage compression heat pump according to claim 1, characterized in that, The water-side inlet of the condenser (2) and the water-side outlet of the condenser (2) are connected by a branch pipeline; a ball valve (3), an electric regulating valve (4) and a first check valve (5) are provided on the branch pipeline.

7. A waste heat recovery heating system for a thermal power unit using a spray-type coupled two-stage compression heat pump according to claim 1, characterized in that, A heat network heater (6) is provided between the water-side outlet of the condenser (2) and the primary network water supply pipeline; the water-side inlet of the heat network heater (6) is connected to the water-side outlet of the condenser (2), and the water-side outlet of the heat network heater (6) is connected to the primary network water supply pipeline; the steam-side inlet of the heat network heater (6) is connected to the heating steam extraction; and the steam-side outlet of the heat network heater (6) is connected to the deaerator.

8. A waste heat recovery heating system for a thermal power unit using a spray-type coupled two-stage compression heat pump according to claim 7, characterized in that, A second check valve (7) is installed on the steam-side inlet pipe of the heat network heater (6), and a heat network drain pump (8) is installed on the steam-side outlet pipe of the heat network heater (6).

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