A low-grade waste heat cascade utilization centralized heating system for a coking production process

Abstract

The utility model discloses a kind of low-grade waste heat cascade utilization central heating systems in coking production process, including dry quenching waste heat boiler, first heating unit, secondary heating unit and tertiary heating unit, and heat supply once backwater is connected first heating unit, secondary heating unit and tertiary heating unit in turn to carry out heat supply;The first heating unit includes steam turbine and steam condenser;The secondary heating unit includes refrigerator, primary cooler and waste heat water heat exchanger;The tertiary heating unit includes cooling tower, primary cooler and absorption heat pump, the cooling tower is connected with primary cooler middle section, and the absorption heat pump is connected on the bypass pipeline that cooling tower and primary cooler middle section are connected;The system is recycled to the steam waste heat generated by steam turbine by the first heating unit set, the waste heat water on primary cooler upper section is recycled by the secondary heating unit set, the waste heat water on primary cooler middle section is recycled by the tertiary heating unit set.

Description

Technical Field

[0001] This utility model belongs to the field of waste heat utilization technology, specifically relating to a centralized heating system for the cascade utilization of low-grade waste heat in the coking production process. Background Technology

[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.

[0003] Coking processes generate a large amount of low-grade waste heat, such as exhaust steam from steam turbines and waste heat from primary cooler cooling water. Currently, much of this energy is wasted. Traditional waste heat recovery methods have the following limitations: 1. Inefficient use of exhaust steam heat: Low-temperature, low-pressure exhaust steam from steam turbines is typically discharged directly through air-cooled islands or water-cooled systems, resulting in heat loss to the atmosphere and low recovery efficiency. 2. Inefficient primary cooler waste heat recovery: The waste water (70–75℃) in the upper section of the primary cooler is used to drive refrigeration units in summer, and only a small portion is used for plant heating in winter. The remaining heat is lost through cooling towers, resulting in high water consumption. 3. The cooling water (40–50℃) in the middle section of the primary cooler is too low to be directly utilized and is usually cooled through cooling towers, leading to energy and water waste. 4. Insufficient coordination between heating and waste heat: Urban centralized heating demand is increasing, but new heat sources rely on coal or natural gas, resulting in high costs and large carbon emissions. Although the low-grade waste heat from coking plants can be used for heating, there is a lack of cascade utilization technology, making it impossible to match heating scenarios with different temperature requirements.

[0004] Therefore, traditional waste heat recovery methods in coking processes, such as dry quenching waste heat power generation and recovery of sensible heat from raw coal gas in riser pipes, focus on a single heat source and fail to achieve system integration and flexible allocation of multi-grade waste heat, resulting in low waste heat utilization rate. Utility Model Content

[0005] The purpose of this utility model is to provide a centralized heating system for the cascade utilization of low-grade waste heat in the coking production process, which can realize the recovery of waste heat from turbine exhaust steam, waste water in the upper section of the primary cooler, and cooling water in the middle section, and can achieve heating through cascade utilization.

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution: In a first aspect, embodiments of this utility model provide a centralized heating system for the cascade utilization of low-grade waste heat in coking production processes, comprising a dry quenching waste heat boiler, a primary heating unit, a secondary heating unit, and a tertiary heating unit. The primary return water for heating is sequentially connected to the primary, secondary, and tertiary heating units for heat supply. The primary heating unit includes a steam turbine and a waste steam condenser. The steam inlet of the steam turbine is connected to the dry quenching waste heat boiler, and the waste steam outlet of the steam turbine is connected to the waste steam condenser. The secondary heating unit includes a chiller, a primary cooler, and a waste water heat exchanger. The chiller is connected to the upper section of the primary cooler, and the waste water heat exchanger is connected to a bypass pipeline connecting the chiller and the primary cooler. The tertiary heating unit includes a cooling tower, a primary cooler, and an absorption heat pump. The cooling tower is connected to the middle section of the primary cooler, and the absorption heat pump is connected to a bypass pipeline connecting the cooling tower and the middle section of the primary cooler.

[0007] As a further technical solution, the exhaust steam outlet of the steam turbine is also connected to an air-cooled island, which is sequentially connected to a hot water well, a deaerator, and the inlet of a dry quenching waste heat boiler.

[0008] As a further technical solution, the primary return water for heating is sequentially connected to the exhaust steam condenser of the primary heating unit, the waste water heat exchanger of the secondary heating unit, and the absorption heat pump of the tertiary heating unit.

[0009] As a further technical solution, the waste water heat exchanger and the absorption heat pump are connected to the primary return water pipeline of the heating system via a bypass pipeline.

[0010] As a further technical solution, the absorption heat pump is provided with a driving end, a heat absorption end and a heat release end. The driving end is connected to the steam extraction port on the low-pressure cylinder of the steam turbine through a steam pipe. The heat absorption end and the heat release end are both connected to the primary return water of the heating system through bypass pipes.

[0011] As a further technical solution, the bypass pipe connecting the heat absorption end to the primary return water is located before the primary heating unit, and the bypass pipe connecting the heat release end to the primary return water is located after the secondary heating unit.

[0012] As a further technical solution, the heat absorption end of the absorption heat pump is also connected to the cooling water outlet of the middle section of the primary cooler.

[0013] As a further technical solution, the exhaust steam condenser adopts a steam-water heat exchanger, and the exhaust steam condenser is provided with a non-condensable gas extraction port, which is connected to the air-cooled island through an extraction pipe.

[0014] As a further technical solution, the cooling water outlet of the primary cooler is sequentially connected to the cooling water tower, the first cooling water circulation pump, and the cooling water of the primary cooler to form a closed loop.

[0015] As a further technical solution, the waste hot water outlet of the upper section of the primary cooler is sequentially connected to the chiller, the second cooling water circulation pump and the cooling water inlet of the upper section of the primary cooler to form a closed loop.

[0016] The beneficial effects of the above-described embodiments of this utility model are as follows: The system provided by this utility model recovers the waste heat from the exhaust steam generated by the steam turbine through a primary heating unit, recovers the waste water in the upper section of the primary cooler through a secondary heating unit, and recovers the waste water in the middle section of the primary cooler through a tertiary heating unit. The primary return water for heating is heated sequentially through the primary, secondary, and tertiary heating units and then used for centralized heating. This method can meet the heating requirements of urban areas. The recovery of low-grade waste heat for centralized heating can improve the energy utilization rate of coking plants and replace the consumption of traditional primary energy sources such as coal and natural gas, thereby reducing the overall energy efficiency of the region.

[0017] This invention transforms low-grade waste heat from coking plants into a heating source, turning waste into treasure. It represents a typical application of the circular economy in industrial energy conservation, increasing the economic benefits of coking plants while enhancing their social responsibility and competitiveness. Simultaneously, the low-grade waste heat from coking production, as a new heat source for urban areas, can also address the heating shortage problem in urban development, serving as an important way to ensure people's livelihoods. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0019] Figure 1 This is a schematic diagram of a centralized heating system for the cascade utilization of low-grade waste heat in the coking production process, which is based on this utility model.

[0020] The diagram is for illustrative purposes only. The components include: 1. Dry quenching waste heat boiler; 2. Boiler feed water pump; 3. Deaerator; 4. Condensate pump; 5. Hot water well; 6. Air-cooled island; 7. Exhaust steam condenser; 8. Secondary heating unit shut-off valve; 9. First heating water switching valve; 10. Second heating water switching valve; 11. Third heating water switching valve; 12. Heating water circulation pump; 13. Fourth heating water switching valve; 14. Absorption heat pump; 15. First cooling water circulation pump; 16. Cooling tower; 17. Intermediate cooling water shut-off valve; 18. First intermediate cooling water bypass valve; 19. Second intermediate cooling water bypass valve; 20. Primary cooler; 21. Second cooling water circulation pump; 22. Waste water heat exchanger; 23. Upper low-temperature water shut-off valve; 24. Refrigeration unit; 25. Generator; 26. Steam turbine; 27. Exhaust steam bypass valve; 28. Exhaust steam shut-off valve; 29. ​​Steam valve. Detailed Implementation

[0021] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 In a typical embodiment of this utility model, such as Figure 1 As shown, a centralized heating system for the cascade utilization of low-grade waste heat in coking production is provided, including a dry quenching waste heat boiler 1, a primary heating unit, a secondary heating unit, and a tertiary heating unit. The primary return water is sequentially connected to the primary, secondary, and tertiary heating units for heating. The primary heating unit includes a steam turbine 26 and a waste steam condenser 7. The steam inlet of the steam turbine 26 is connected to the dry quenching waste heat boiler 1, and the waste steam outlet of the steam turbine 26 is connected to the waste steam condenser 7. The secondary heating unit includes a chiller 24, a primary cooler 20, and a waste water heat exchanger 22. The chiller 24 is connected to the upper section of the primary cooler 20, and the waste water heat exchanger 22 is connected to a bypass pipe connecting the chiller 24 and the primary cooler 20. The tertiary heating unit includes a cooling tower 16, a primary cooler 20, and an absorption heat pump. The cooling tower 16 is connected to the middle section of the primary cooler 20, and the absorption heat pump 14 is connected to a bypass pipe connecting the cooling tower 16 and the middle section of the primary cooler 20.

[0023] The aforementioned system recovers waste heat from the exhaust steam generated by the turbine through a primary heating unit, recovers waste water from the upper section of the primary cooler through a secondary heating unit, and recovers waste water from the middle section of the primary cooler through a tertiary heating unit. The primary return water for heating is heated sequentially through the primary, secondary, and tertiary heating units and then used for centralized heating. This method can meet the heating requirements of urban areas. Recovering low-grade waste heat for centralized heating can improve the energy utilization rate of coking plants and can replace the consumption of traditional primary energy sources such as coal and natural gas, thereby reducing the overall energy efficiency of the region.

[0024] Specifically, the primary heating unit also includes a waste steam pipeline and a condensate pipeline. A waste steam shut-off valve 28 and a waste steam bypass pipe are installed on the inlet condensate pipeline of the air-cooled island 6, with the bypass pipe connected to the inlet of the waste steam condenser 7. A shut-off valve and a condensate bypass pipe are installed on the condensate pipeline of the air-cooled island 6, with the bypass pipe connected to the condensate outlet pipeline of the waste steam condenser. The waste steam condenser 7 directly condenses the waste steam discharged from the turbine 26 via heating water, recovering waste heat from the waste steam and achieving primary heating of the heating water. The pressure and temperature of the waste steam, i.e., the turbine exhaust pressure and temperature during the heating season, are correspondingly increased, which will have a certain impact on the turbine's power generation, but the power generation loss is far lower than the heat sales revenue.

[0025] The exhaust steam condenser can be one or more steam-water heat exchangers, directly adopting the existing structure. Furthermore, the condenser is equipped with a non-condensable gas extraction port, which is connected to the existing non-condensable gas extraction pipeline of the air-cooled island, and is equipped with an electric switching valve (not shown in the figure).

[0026] The waste hot water outlet of the upper section of the primary cooler in the second heating unit is sequentially connected to the chiller 24, the second cooling water circulation pump 21, and the cooling water inlet of the upper section of the primary cooler to form a closed loop. The second heating unit also includes waste hot water pipes and heating water pipes. An upper-section low-temperature water shut-off valve is installed on the waste hot water outlet pipe of the upper section of the primary cooler, and a bypass pipe is set up, which connects to the hot side inlet and outlet of the waste hot water heat exchanger 22; a secondary heating unit shut-off valve 8 is installed on the heating water pipe after the exhaust steam condenser 7, and a bypass pipe is set up, which connects to the heating water side inlet and outlet of the waste hot water heat exchanger. The waste hot water heat exchanger utilizes the waste hot water in the upper section of the primary cooler to directly exchange heat with the heating water, realizing secondary heating of the heating water.

[0027] The waste water heat exchanger is one or more detachable plate heat exchangers, with plates made of 304 or 316L stainless steel. This avoids the heating water from directly entering the horizontal tube cooler and exchanging heat with the gas. The indirect heating of the heating water solves the problem of poor gas cooling effect caused by scale buildup in the poor quality of the heating water.

[0028] The intermediate cooling water outlet of the primary cooler in the three-stage heating unit is sequentially connected to the cooling tower, the first cooling water circulation pump 15, and the intermediate cooling water of the primary cooler to form a closed loop. The three-stage heating unit also includes cooling water pipes, steam pipes, and heating water pipes. A mid-stage cooling water shut-off valve 17 is installed on the intermediate cooling water outlet pipe of the primary cooler, and a bypass is provided. The bypass pipe connects to the inlet and outlet of the low-temperature water side of the absorption heat pump. A second heating water switching valve 10 is installed on the heating water pipe after the exhaust steam condenser, and a bypass pipe is provided. The heating water bypass pipe connects to the inlet and outlet of the heating water side of the absorption heat pump. The condensate outlet of the absorption heat pump, the condensate outlet of the exhaust steam condenser, and the condensate pipe of the air-cooled island are connected and equipped with electrically operated switching valves. Condensate pumps are installed at the condensate outlets of the absorption heat pump and the exhaust steam condenser (not shown in the figure).

[0029] In this embodiment, the exhaust steam outlet of the steam turbine 26 is also connected to the air-cooled island 6, which is sequentially connected to the hot water well 5, the deaerator 3, and the water inlet of the dry quenching waste heat boiler 1.

[0030] Specifically, a waste steam shut-off valve 28 is installed on the pipeline connecting the exhaust steam outlet of the steam turbine 26 to the air-cooled island 6. A condensate pump is installed on the pipeline connecting the hot water well 5 to the deaerator 3, and a boiler feed water pump is installed on the pipeline connecting the deaerator 3 to the dry quenching waste heat boiler 1.

[0031] In this embodiment, the primary return water for heating is sequentially connected to the exhaust steam condenser 7 of the primary heating unit, the waste water heat exchanger 22 of the secondary heating unit, and the absorption heat pump 14 of the tertiary heating unit. The waste water heat exchanger 22 and the absorption heat pump 14 are connected to the primary return water pipeline for heating via bypass pipelines.

[0032] In this embodiment, the absorption heat pump is a steam-driven lithium bromide heat pump, which uses steam extracted from the steam turbine as the driving heat source and utilizes the waste heat of the cooling water in the middle section of the primary cooler or the return water of the heating water to carry out tertiary heating on the basis of the secondary heating of the waste water in the upper section of the primary cooler. By utilizing the performance of this heat pump, the heat of the middle section cooling water can be recovered while consuming steam, thereby meeting the heating water supply temperature requirements and further reducing the consumption of heating steam.

[0033] Absorption heat pumps directly utilize existing structures. An absorption heat pump typically includes a drive end, an absorption end, and a heat release end. The drive end is connected to the extraction port on the low-pressure cylinder of the steam turbine via a steam pipe. Both the absorption end and the heat release end are connected to the primary return water supply via bypass pipes. Furthermore, the bypass pipe connecting the absorption end to the primary return water supply is located before the first-stage heating unit, and the bypass pipe connecting the heat release end to the primary return water supply is located after the second-stage heating unit. Additionally, the absorption end of the absorption heat pump is also connected to the cooling water outlet of the middle section of the primary cooler.

[0034] Specifically, the low-pressure cylinder of the steam turbine is equipped with an extraction port, which is connected to the steam interface of the absorption heat pump via a steam pipeline. The steam pipeline is equipped with a steam valve and a desuperheating and pressure reducing device to desuperheat the superheated steam into saturated steam. A third heating water switching valve 11 is installed on the primary network return water pipeline, and bypasses are installed before and after the third heating water switching valve 11. The bypasses are respectively connected to the inlet and outlet of the low-temperature water of the absorption heat pump and are connected in parallel with the water in the middle section of the primary cooler.

[0035] When the turbine unit operates at maximum extraction capacity, overall heat balance calculations are performed based on the required water supply temperature, especially when the initial and final water supply temperatures are below 80℃. Under normal circumstances, all exhaust steam can be condensed, eliminating the need for air-cooled condensation. The absorption heat pump utilizes the waste heat from the intermediate cooling water in the primary cooler. The absorption heat pump is designed with a steam inlet temperature of 0.6MPa at 165℃ and a steam condensate temperature of 80℃; the intermediate cooling water inlet temperature is 48℃, and the outlet temperature is 40℃; heating water is heated from 68.5℃ to 75-80℃.

[0036] When the turbine unit operates at maximum extraction capacity, and the required supply water temperature during extremely cold periods is 80–90°C, overall heat balance calculations show that not all exhaust steam can be condensed by the heating water. A small amount of exhaust steam requires condensation in the air-cooled island. However, during extremely cold periods, the low temperatures can easily cause the air-cooled island to freeze and be damaged. To solve this problem, this system incorporates a heating water pre-cooling system. Instead of utilizing the waste heat from the cooling water in the primary cooler, the absorption heat pump pre-cools the heating water. Specifically, the heating water return water first enters the absorption heat pump between 48°C and 43°C, then enters the exhaust steam condenser where it is heated to 63°C, condensing all the exhaust steam. Finally, the heating water is heated to 80–90°C for external heating. With this operating mode, the absorption heat pump changes from utilizing the waste heat of the intermediate cooling water in the initial and final stages to indirectly utilizing the waste heat of the exhaust steam. Without increasing the steam consumption of the heat pump, it solves the problem of easy icing of a small amount of exhaust steam entering the air-cooled island during extremely cold periods, and improves the stability and adjustment flexibility of the system.

[0037] The operating principle of this system is as follows: During the colder months at the beginning and end of the heating season, the heating water return first enters the condenser, where it is heated in the first stage by the exhaust steam from the turbine. The condensate from this exhaust steam is then pumped to the condensate hot water well. The heating water then enters the upper waste water heat exchanger, where it is heated in the second stage by the upper waste water. The cooled upper waste water then enters the upper section of the primary cooler to cool the coal gas, which is then heated again. Finally, the heating water enters the absorption heat pump, where it is heated in the third stage by the steam and the waste heat from the intermediate cooling water in the primary cooler. The steam condensate is then pumped to the condensate hot water well. The intermediate cooling water enters the cooling tower for further cooling, and then enters the intermediate cooling gas in the primary cooler via a cooling water circulation pump, where it is heated again. Finally, the heating water is sent to each secondary heat exchange station, where it exchanges heat with the secondary heating water for cooling before returning to the condenser.

[0038] During the coldest period of the heating season, the heating water return first undergoes pre-cooling by an absorption heat pump before entering the condenser. There, it is heated first-stage by the exhaust steam from the turbine, and the exhaust steam condensate is pumped to the condensate hot water well. The heating water then enters the upper waste water heat exchanger, where it is heated second-stage by the upper waste water. This cooled upper waste water then enters the upper section of the primary cooler to cool the coal gas again. Finally, the heating water enters the absorption heat pump, where it is heated tertiarily by steam and the heating water return. The steam condensate is pumped to the condensate hot water well. The heating water is ultimately sent to each secondary heat exchange station, where it exchanges heat with the secondary heating water for cooling before returning to the condenser.

[0039] In one specific embodiment of this example, the waste steam condenser is designed with a waste steam inlet temperature of 65°C, a waste steam condensate temperature of 64°C, a heating water inlet temperature of 40°C, and a heating water outlet temperature of 63.5°C; the waste hot water inlet temperature is designed to be 73°C, and the outlet temperature to be 65°C; the heating water inlet temperature is 63.5°C, and the outlet temperature to be 68.5°C; the absorption heat pump is designed with a steam inlet temperature of 0.6MPa at 165°C, and a steam condensate temperature of 80°C; the intermediate cooling water inlet temperature is 48°C, and the outlet temperature to be 40°C; the heating water is heated from 68.5°C to 75-80°C. Taking a coking plant with an annual production capacity of 2 million tons as an example, the cascade heating of heating water using the above system includes the following steps: At the beginning and end of the heating season, the required water supply temperature is low, and the system operates with a large flow of heating water. The 40°C heating return water first enters the condenser and is heated to 63.5°C by the exhaust steam. The 65°C exhaust steam is condensed to 64°C and then sent to the hot water well via the condensate pump. The 63.5°C heating water then enters the upper waste hot water heat exchanger and is heated to 69°C by the upper cooling water, which is then cooled from 72°C to 65°C. The 69°C heating water finally enters the absorption heat pump and is heated to 75-80°C before being sent to the heating users. The steam extracted from the low-pressure cylinder of the steam turbine becomes saturated steam at 0.6MPa and 165°C after desuperheating and depressurization. It enters the heat pump, condenses into water, and is then sent to the hot water well. The cooling water in the middle section of the primary cooler is cooled from 48°C to 40°C before entering the cooling tower for further cooling.

[0040] During the extremely cold period of the heating season, the required water supply temperature is 80-90℃. To reduce the amount of heating water used in the system, the 48℃ heating return water first enters the absorption heat pump to cool down to 43℃. The 43℃ heating water then enters the exhaust steam condenser to be heated to 63.5℃. The 65℃ exhaust steam is completely condensed to 64℃ and then sent to the hot water well via the condensate pump. The 63.5℃ heating water then enters the upper waste hot water heat exchanger to be heated to 69℃ by the upper cooling water, which is then cooled from 72℃ to 65℃. The 69℃ heating water finally enters the absorption heat pump to be heated to 80-90℃ before being sent to the heating users. The steam extracted from the low-pressure cylinder of the steam turbine becomes saturated steam at 0.6MPa and 165℃ after desuperheating and depressurization. It then enters the heat pump, condenses into water, and is sent to the hot water well. The cooling water in the middle section of the primary cooler no longer enters the heat pump.

[0041] The above operating parameters are continuously adjusted according to weather changes to maximize the recovery and utilization of waste heat.

[0042] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A centralized heating system for the cascade utilization of low-grade waste heat in coking production, characterized in that, The system includes a dry quenching waste heat boiler, a primary heating unit, a secondary heating unit, and a tertiary heating unit. The primary return water for heating is sequentially connected to these three units. The primary heating unit includes a steam turbine and a waste steam condenser. The steam inlet of the steam turbine is connected to the dry quenching waste heat boiler, and the waste steam outlet of the steam turbine is connected to the waste steam condenser. The secondary heating unit includes a chiller, a primary cooler, and a waste water heat exchanger. The chiller is connected to the upper section of the primary cooler, and the waste water heat exchanger is connected to a bypass pipe connecting the chiller and the primary cooler. The tertiary heating unit includes a cooling tower, a primary cooler, and an absorption heat pump. The cooling tower is connected to the middle section of the primary cooler, and the absorption heat pump is connected to a bypass pipe connecting the cooling tower and the middle section of the primary cooler.

2. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 1, characterized in that, The exhaust steam outlet of the steam turbine is also connected to an air-cooled island, which is sequentially connected to a hot water well, a deaerator, and the inlet of a dry quenching waste heat boiler.

3. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 1, characterized in that, The primary return water supply is sequentially connected to the exhaust steam condenser of the primary heating unit, the waste water heat exchanger of the secondary heating unit, and the absorption heat pump of the tertiary heating unit.

4. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 3, characterized in that, The waste water heat exchanger and absorption heat pump are connected to the primary return water pipeline of the heating system via a bypass pipeline.

5. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 1, characterized in that, The absorption heat pump is equipped with a drive end, a heat absorption end, and a heat release end. The drive end is connected to the steam extraction port on the low-pressure cylinder of the steam turbine via a steam pipe. Both the heat absorption end and the heat release end are connected to the primary return water of the heating system via bypass pipes.

6. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 5, characterized in that, The bypass pipe connecting the heat absorption end to the primary return water is located before the primary heating unit, and the bypass pipe connecting the heat release end to the primary return water is located after the secondary heating unit.

7. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 5, characterized in that, The heat absorption end of the absorption heat pump is also connected to the cooling water outlet in the middle section of the primary cooler.

8. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 1, characterized in that, The exhaust steam condenser uses a steam-water heat exchanger and is equipped with a non-condensable gas extraction port, which is connected to the air-cooled island via an extraction pipe.

9. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 1, characterized in that, The cooling water outlet of the middle section of the primary cooler is sequentially connected to the cooling water tower, the first cooling water circulation pump, and the cooling water of the middle section of the primary cooler to form a closed loop.

10. The centralized heating system for the cascade utilization of low-grade waste heat in the coking production process as described in claim 1, characterized in that, The waste water outlet of the upper section of the primary cooler is sequentially connected to the chiller, the second cooling water circulation pump, and the cooling water inlet of the upper section of the primary cooler to form a closed loop.

Images