Gradient utilization system for chemical waste heat

Abstract

The invention relates to the technical field of waste heat recovery, in particular to a chemical waste heat gradient utilization system. The chemical waste heat gradient utilization system comprises a distributed waste heat recovery energy station group, a centralized peak regulation energy station, a regional basic heat source power plant, a heat supply network conveying system and an intelligent regulation and control system, and the distributed waste heat recovery energy station group is composed of a plurality of waste heat recovery units arranged in an industrial park. Process waste heat at different temperature levels is extracted and heated in a stepped mode through multiple sets of parallel plate type heat exchanger sets and multiple stages of heat pump units, and a centralized peak shaving energy station is responsible for conducting peak shaving heating on recycled waste heat and is connected with a regional basic heat source power plant through a heat supply pipe network to jointly provide stable heat loads. And the intelligent regulation and control system dynamically coordinates heat distribution and operation of each energy station. By means of multi-source cooperation and gradient utilization, the industrial waste heat recovery efficiency and the heat supply stability are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a cascade utilization system for chemical waste heat. Background Technology

[0002] Existing industrial waste heat recovery systems face numerous technical bottlenecks and systemic defects in addressing the complex and ever-changing industrial heating demands. These are primarily manifested in the following aspects: First, traditional waste heat recovery devices typically employ a single, extensive recovery model, which is ill-suited to the refined utilization needs of multi-temperature, multi-quality waste heat resources in industrial parks. Most systems can only handle waste heat within a fixed temperature range, lacking effective methods for graded extraction and tiered utilization of waste heat across a wide temperature range of 40-80℃. This results in a significant amount of medium- and low-temperature waste heat not being fully utilized, with overall waste heat recovery rates generally below 50%. Second, existing heating systems often employ centralized heat source configurations, failing to achieve efficient local utilization of waste heat resources. Long-distance transmission leads to severe heat loss, and the network thermal efficiency is typically less than 80%. Regarding heat source allocation, conventional systems lack flexible peak-shaving methods, making it difficult to balance the contradiction between the volatility of industrial waste heat and the stability of user demand. Heating quality is difficult to guarantee, with temperature fluctuations frequently exceeding ±5℃.

[0003] At the equipment level, traditional heat pump systems mostly use a single type of heat pump unit, which cannot cover the complete heating chain from low to high temperatures. Ordinary centrifugal heat pumps experience a significant drop in energy efficiency ratio at high temperatures, while absorption heat pumps have stringent requirements for the temperature of the driving heat source, and the overall system COP is typically below 4.0. Regarding heat exchange equipment, conventional plate heat exchangers are ill-suited to the high fouling characteristics of industrial waste heat media, resulting in a rapid decline in heat exchange efficiency over operating time, short maintenance cycles, and severely impacting the stability of continuous system operation. In terms of control strategies, existing systems lack intelligent multi-variable coordinated control capabilities, making it difficult to respond promptly to process fluctuations and load changes, with adjustment lag times as long as 5-10 minutes, leading to energy waste and a decline in heating quality.

[0004] Furthermore, the design of the pipeline network system also has significant flaws. Traditional single-temperature zone pipeline networks cannot meet the diverse needs of different levels of heat users, either resulting in the waste of high-quality heat energy or failing to meet the high-temperature requirements of special processes. Return water systems generally lack precise temperature control methods, leading to large fluctuations in return water temperature, directly impacting waste heat recovery efficiency. More importantly, most existing systems cannot achieve coordinated optimization between heating and process steam consumption, resulting in the waste of substantial waste heat resources during the non-heating season and generally low annual system utilization rates. These technological shortcomings severely restrict the large-scale, efficient utilization of industrial waste heat, necessitating the construction of a more intelligent and efficient multi-source coupled heating system through technological innovation. Summary of the Invention

[0005] The technical problem this invention aims to solve is: to address the issues of low waste heat recovery rate, poor heating quality, low equipment energy efficiency, large heat loss in pipeline networks, lagging regulation, and low seasonal utilization rate in existing technologies, as described in the background section, this invention provides a cascade utilization system for chemical waste heat. This system achieves multi-temperature-zone waste heat extraction through distributed waste heat recovery energy stations, and uses a magnetic levitation centrifugal heat pump coupled with three types of absorption heat pumps to improve energy efficiency. A centralized peak-shaving energy station achieves heat peak shaving through a gas-fired boiler and a steam-driven system. An intelligent control system dynamically optimizes operating strategies with a short response time. Multi-temperature-zone pipeline network provides cascaded heating, improving the comprehensive utilization rate of waste heat and solving the problems of low recovery rate, poor energy efficiency, and lagging regulation in traditional systems.

[0006] The technical solution adopted by this invention to solve its technical problem is: a chemical waste heat cascade utilization system, comprising: The distributed waste heat recovery energy station group includes multiple waste heat recovery units set up in multiple circulating water systems in industrial parks, which are used to extract and utilize process waste heat at different temperatures in stages. A centralized peak-shaving energy station is connected to the distributed waste heat recovery energy station group and is used for peak-shaving heating of the recovered waste heat; The regional basic heat source power plant is connected to the centralized peak-shaving energy station via heat pipelines to provide basic heat load; The heat network transmission system includes a heat pipeline network connecting the centralized peak-shaving energy station and the regional basic heat source power plant; The intelligent control system is used to dynamically regulate the heat distribution and operation of distributed waste heat recovery energy stations and centralized peak-shaving energy stations.

[0007] The distributed waste heat recovery energy station group achieves efficient and localized recovery of waste heat resources through a multi-point distributed layout. It is located at key nodes of the main circulating water system within the industrial park, forming a grid-like waste heat collection network. The station group adopts a modular design, with each waste heat recovery unit optimized for the waste heat characteristics of specific process stages, achieving tiered recovery and utilization of waste heat from multiple temperature ranges from 40℃ to 80℃. The centralized peak-shaving energy station serves as the core hub of the system, effectively balancing the instability of the distributed energy station's output through an intelligent heat allocation mechanism, ensuring heating quality. The regional basic heat source power plant and the peak-shaving energy station form a complementary operation mode, providing a stable basic heat load guarantee when the peak-shaving energy station cannot meet demand. The heat network transmission system adopts a multi-temperature zone pipeline design, achieving efficient heat transmission and reducing transmission losses through optimized pipeline layout and insulation measures. The intelligent control system is built based on IoT technology, dynamically optimizing system operation strategies by monitoring the operating parameters of each node in real time, thereby improving overall energy efficiency.

[0008] According to one embodiment of the present invention, the distributed waste heat recovery energy station group includes multiple sets of plate heat exchanger groups and multi-stage heat pump units connected in parallel. The multiple sets of plate heat exchanger groups are respectively connected to waste heat sources at different temperature levels, and the multi-stage heat pump units receive hot water from different plate heat exchanger groups and perform cascade heating.

[0009] The distributed waste heat recovery energy station uses multiple sets of plate heat exchangers connected in parallel to form the waste heat collection front end. Each heat exchanger is optimized for waste heat in a specific temperature range. The multi-stage heat pump unit can automatically adjust its operation combination according to changes in waste heat quality.

[0010] According to one embodiment of the present invention, the heat pump unit adopts a series or parallel coupled arrangement, which includes a magnetic levitation centrifugal heat pump and an absorption heat pump. The magnetic levitation centrifugal heat pump is used for medium and high temperature heating, and the absorption heat pump includes a type I absorption heat pump, a type II absorption heat pump and a type III absorption heat pump.

[0011] The heat pump units adopt a series or parallel coupling arrangement. The magnetic levitation centrifugal heat pump is responsible for heating the medium and high temperature range. Type I absorption heat pumps, Type II absorption heat pumps, and Type III absorption heat pumps handle the high, medium, and low temperature ranges respectively, forming a complete temperature rise chain. This enables the system to automatically select the optimal heat pump combination according to the real-time heat load demand, resulting in low operating energy consumption.

[0012] According to one embodiment of the present invention, the distributed waste heat recovery energy station simultaneously processes at least two types of return water with different initial temperatures. An independent heating path is set for each type of return water, and the processed hot water at the same temperature is mixed and output. This ensures precise processing of hot water at different temperatures, and the processed hot water achieves temperature uniformity at the outlet mixer, significantly improving heating stability.

[0013] According to one embodiment of the present invention, the distributed waste heat recovery energy station group includes a first output pipeline and a second output pipeline. The first output pipeline is connected to a centralized peak-shaving energy station and then directly connected to the heating network. The second output pipeline is connected to the heating network after being heated by the centralized peak-shaving energy station and the regional basic heat source power plant in sequence.

[0014] The first output pipeline adopts a direct supply mode, reducing heat exchange links and is suitable for areas with low temperature requirements; the second output pipeline undergoes two-stage heating to ensure high-quality heat demand areas; the heat can be flexibly allocated according to the heat demand characteristics of different areas, and the system's regulation capability and the hydraulic balance of the pipeline network are both improved.

[0015] According to one embodiment of the present invention, the distributed waste heat recovery energy station further includes a waste heat protection system, which includes a plate heat exchanger connected to the heat pump evaporator for maintaining a minimum recovery temperature of the waste heat source.

[0016] The waste heat protection system, through the closed-loop design of plate heat exchangers and heat pump evaporators, ensures that the waste heat temperature is not lower than the critical value of 35°C. It automatically starts when the water supply is insufficient, ensuring the stable operation of the heat pump unit and improving its reliability.

[0017] According to one embodiment of the present invention, the intelligent control system dynamically adjusts according to the return water temperature. When the return water temperature is detected to be higher than a first set value, the heat pump unit is started first for cooling. When the return water temperature is detected to be lower than a second set value, the plate heat exchanger group is used first for primary heating.

[0018] According to one embodiment of the present invention, the distributed waste heat recovery energy station includes a first waste heat recovery unit, a second waste heat recovery unit, a third waste heat recovery unit, a fourth waste heat recovery unit, a fifth waste heat recovery unit, a sixth waste heat recovery unit, a seventh waste heat recovery unit, an eighth waste heat recovery unit, a ninth waste heat recovery unit, a tenth waste heat recovery unit, an eleventh waste heat recovery unit, and a twelfth waste heat recovery unit; the first waste heat recovery unit includes a plate heat exchanger, a centrifugal heat pump, and an absorption heat pump, which processes municipal 30°C return water through a three-stage heating system. The first waste heat recovery unit heats the municipal 30°C return water to 90°C through a five-stage heating process; the second waste heat recovery unit includes a plate heat exchanger, a centrifugal heat pump, and an absorption heat pump, which heats the municipal 30°C return water to 94.4°C through a five-stage heating process; the third waste heat recovery unit includes a plate heat exchanger and an absorption heat pump, which heats the municipal 30°C return water to 91°C through a six-stage heating process; the fourth waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump, which heats the municipal 30°C return water to 80°C through a five-stage heating process; the fifth waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump. The municipal 30℃ return water is heated to 80℃ through a five-stage heating process; the sixth waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump, which heats the municipal 30℃ return water to 80℃ through a six-stage heating process; the seventh waste heat recovery unit includes a plate heat exchanger, a centrifugal heat pump, and an absorption heat pump, which heats the municipal 30℃ return water to 100℃ through an eight-stage heating process; the eighth waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump, which heats the municipal 30℃ return water to 80℃ through a five-stage heating process; the ninth waste heat recovery unit includes a plate heat exchanger and... The magnetic levitation centrifugal heat pump heats the municipal 30°C return water to 80°C through five stages of heating; the tenth waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump, which heats the municipal 30°C return water to 85°C through four stages of heating; the eleventh waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump, which heats the 40°C return water to 55°C through both the plate heat exchanger and the magnetic levitation centrifugal heat pump; the twelfth waste heat recovery unit includes a plate heat exchanger and a magnetic levitation centrifugal heat pump, which heats the municipal 30°C return water to 85°C through four stages of heating.

[0019] The twelve waste heat recovery units are specifically optimized for different process conditions. The first waste heat recovery unit adopts a rapid heating design, the seventh waste heat recovery unit achieves eight-stage heating with precise control of the temperature gradient, and the eleventh waste heat recovery unit is specially designed for low-temperature return water. It adopts a two-stage preheating technology to efficiently raise the temperature of the 40℃ return water to 55℃, thereby improving the energy efficiency ratio of each unit under its applicable operating conditions.

[0020] According to one embodiment of the present invention, the centralized peak-shaving energy station includes a gas-fired boiler system and a steam-driven system, wherein the steam-driven system includes a steam-driven heat pump, a steam-type absorption heat pump, and a flash compressor.

[0021] The high-temperature steam generated by the gas boiler first drives the steam turbine to generate electricity, the waste heat drives the centrifugal heat pump, and finally the heat is fully utilized through the absorption heat pump; the flash compression device converts the low-temperature waste heat into usable steam.

[0022] According to one embodiment of the present invention, the heating network delivery system includes a heating network for 105°C hot water, a heating network for 95°C hot water, and a return water network for 30°C hot water.

[0023] The beneficial effects of the present invention: In view of the technical defects of existing industrial waste heat utilization systems, the present invention proposes a multi-source coupled heating system, which realizes the efficient utilization of waste heat resources; In the waste heat recovery stage, the system adopts a distributed energy station layout, with each station equipped with multiple sets of parallel plate heat exchanger groups. It is designed for waste heat at different temperature levels and achieves graded extraction of waste heat through a modular structure, which improves the waste heat capture rate compared with the traditional single recovery method. The heat pump system innovatively adopts a coupled configuration of magnetic levitation centrifugal heat pump and three types of absorption heat pump. The magnetic levitation centrifugal heat pump is responsible for heating in the medium and high temperature range; the three types of absorption heat pumps handle different temperature zones respectively, covering high, medium and low temperature ranges, forming a complete temperature enhancement chain and improving the overall energy efficiency of the system. The peak shaving process is equipped with a coordinated operation mechanism between the gas boiler and the steam drive system. High-temperature steam first drives the steam turbine to generate electricity, waste heat drives the centrifugal heat pump, and finally the absorption heat pump is used for deep utilization. A flash compression device is also equipped to convert low-temperature waste heat into usable steam, thereby improving the overall energy utilization rate of the peak shaving system. The intelligent control system adopts a three-level architecture and uses Internet of Things (IoT) technology to achieve real-time monitoring and dynamic optimization, which shortens the response time and improves the system's adjustment capability. Through technological innovations such as waste heat staged extraction, multi-type heat pump coupling, intelligent dynamic control, and multi-temperature zone network coordination, this system has greatly improved the comprehensive utilization rate of waste heat and effectively controlled heating temperature fluctuations. During the non-heating season, the system's annual utilization rate is increased through the production of process steam, comprehensively solving the technical problems of low waste heat recovery rate, poor energy efficiency, lagging control, and low seasonal utilization rate of traditional systems. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a process block diagram of the present invention.

[0026] Figure 2 This is a process block diagram of a specific embodiment of the present invention.

[0027] Figure 3 yes Figure 2 Process flow diagram of the second centralized peak-shaving energy station in China.

[0028] Figure 4 yes Figure 2 Process flow diagram of the first waste heat recovery unit.

[0029] Figure 5 yes Figure 2 Process flow diagram of the second waste heat recovery unit.

[0030] Figure 6 yes Figure 2 Process flow diagram of the third waste heat recovery unit.

[0031] Figure 7 yes Figure 2 Process flow diagram of the fourth waste heat recovery unit.

[0032] Figure 8 yes Figure 2 Process flow diagram of the fifth waste heat recovery unit.

[0033] Figure 9 yes Figure 2 Process flow diagram of the sixth waste heat recovery unit.

[0034] Figure 10 yes Figure 2 Process flow diagram of the seventh waste heat recovery unit.

[0035] Figure 11 yes Figure 2 Process flow diagram of the eighth waste heat recovery unit.

[0036] Figure 12 yes Figure 2 Process flow diagram of the ninth waste heat recovery unit.

[0037] Figure 13 yes Figure 2 Process flow diagram of the tenth waste heat recovery unit.

[0038] Figure 14 yes Figure 13 A schematic diagram of a medium-coupled heat pump unit.

[0039] Figure 15 yes Figure 14 A schematic diagram of the structure of the intermediate coupled heat exchange unit.

[0040] Figure 16 yes Figure 14 Schematic diagram of a medium-coupled heat pump unit.

[0041] Figure 17 yes Figure 2 Process flow diagram of the eleventh waste heat recovery unit.

[0042] Figure 18 yes Figure 2 Process flow diagram of the twelfth waste heat recovery unit.

[0043] Figure 19 This is a schematic diagram of the structure of the magnetically levitated centrifugal heat pump in this invention.

[0044] Figure 20 This is a schematic diagram of the connection structure between the main pipeline and the magnetic levitation centrifugal heat pump in this invention.

[0045] Figure 21 yes Figure 2 Flowchart of the second centralized peak-shaving energy station in China during the non-heating season.

[0046] In the diagram: 1. Distributed waste heat recovery energy station group; 2. Centralized peak-shaving energy station; 3. Regional basic heat source power plant; 4. Heat network transmission system; 11. First distributed waste heat recovery energy station; 111. Tenth waste heat recovery unit; 112. Eleventh waste heat recovery unit; 113. Twelfth waste heat recovery unit; 12. Second distributed waste heat recovery energy station; 121. First waste heat recovery unit; 122. Second waste heat recovery unit; 123. Third waste heat recovery unit; 124. Fourth waste heat recovery unit; 125. Fifth waste heat recovery unit; 126. Sixth waste heat recovery unit; 127. Seventh waste heat recovery unit; 128. Eighth waste heat recovery unit; 129. Ninth waste heat recovery unit; 21. First centralized peak-shaving energy station; 22. Second centralized peak-shaving energy station; 221. Gas boiler; 222. Steam-driven heat pump; 223. Steam-type absorption heat pump; 224. Flash compressor; 41. First heat network delivery system; 42. Second heat network delivery system; 43. Third heat network delivery system; 10. Plate heat exchanger; 20. Centrifugal heat pump; 30. Absorption heat pump; 40. Magnetic levitation centrifugal heat pump; 50, 6011; 60. Coupled heat pump unit; 601. Type I coupler; 602. Type II coupler; 603. Type III coupler; 6011. Coupled heat exchanger; 6012. Absorber; 6021. Condenser; 6022. Generator; 6031. First evaporator; 6032. Second evaporator; 604, circulating water inlet pipe; 605, circulating water outlet pipe; 606, heating water inlet pipe; 607, heating water outlet pipe; 608, refrigerant supply pipe; 609, refrigerant return pipe; 6010, liquid phase working fluid transfer pipe; 6020, gas phase working fluid transfer pipe; 6030, lithium bromide solution circulation pipe; 70, main pipe; 80, connecting branch pipe; 90, on / off valve; 100, evaporator one; 200, condenser one; 300, economizer; 400, first stage compressor; 500, second stage compressor. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0048] like Figure 1As shown, a cascade utilization system for chemical waste heat includes a distributed waste heat recovery energy station group 1, a centralized peak-shaving energy station 2, a regional basic heat source power plant 3, a heat network transmission system 4, and an intelligent control system (not shown in the figure). The distributed waste heat recovery energy station group 1 includes multiple waste heat recovery units located at multiple circulating water systems within the industrial park, used for the graded extraction and utilization of process waste heat at different temperatures. The centralized peak-shaving energy station 2 is connected to the distributed waste heat recovery energy station group 1 and is used for peak-shaving heating of the recovered waste heat. The regional basic heat source power plant 3 is connected to the centralized peak-shaving energy station 2 via heat pipelines, providing basic heat load. The heat network transmission system 4 includes a heat pipeline network connecting the centralized peak-shaving energy station 2 and the regional basic heat source power plant 3. The intelligent control system is used to dynamically regulate the heat distribution and operation of the distributed waste heat recovery energy station 1 and the centralized peak-shaving energy station 2.

[0049] It should be noted that the distributed waste heat recovery energy station group 1 achieves efficient recovery of waste heat at multiple temperature levels by extracting process waste heat from the industrial park in stages; for waste heat at different temperature levels, a cascade heat exchange technology is adopted to maximize the extraction of low-grade heat energy and avoid energy waste; multiple waste heat recovery units operate independently and can be flexibly configured according to the heat load demand of the industrial park, improving system adaptability; through equipment such as plate heat exchanger 10 and absorption heat pump 30, the low-temperature return water is heated to 55℃~95℃ in stages, significantly reducing the dependence on traditional heat sources.

[0050] The following is a specific embodiment: like Figure 2 As shown, the distributed waste heat recovery energy station group 1 includes a first distributed waste heat recovery energy station 11 and a second distributed waste heat recovery energy station 12. Correspondingly, the centralized peak-shaving energy station 2 includes a first centralized peak-shaving energy station 21 and a second centralized peak-shaving energy station 22. The heat network transmission system 4 includes a first heat network transmission system 41, a second heat network transmission system 42, and a third heat network transmission system 43. Specifically, the first distributed waste heat recovery energy station 11 is connected to the first centralized peak-shaving energy station 21, which is connected to the second centralized peak-shaving energy station 22 and the regional basic heat source power plant 3. The regional basic heat source power plant 3 is connected to the first heat network transmission system 41. The second distributed waste heat recovery energy station 12 is connected to the second centralized peak-shaving energy station 22, which is connected to the second heat network transmission system 42 and the third heat network transmission system 43.

[0051] The specific process is as follows: 30℃ heating return water enters each waste heat recovery unit of the first centralized peak-shaving energy station 21 and is heated to 55℃. Part of it is returned to the regional basic heat source power plant 3 for further heating to 105℃; part of it is heated to 85℃ in each waste heat recovery unit by a multi-stage centrifugal heat pump 20 and then heated to 95℃ by the first centralized peak-shaving energy station 21 using the guaranteed steam peak and merged into the first heat network transmission system 41; at the same time, 55℃ waste hot water or 40℃ return water is provided to the second centralized peak-shaving energy station 22 as a low-temperature heat source for the second centralized peak-shaving energy station 22.

[0052] like Figure 3 As shown, the second centralized peak-shaving energy station 22 includes a boiler system formed by two sets of gas-fired boilers 221 and a steam drive system. The steam drive system includes a steam-driven heat pump 222, 18 steam-type absorption heat pumps 223 and a flash compressor 224. The steam-type absorption heat pumps 223 are equipped with a steam-water heat exchanger to ensure the temperature of the heating outlet water. The 18 steam-type absorption heat pumps 223 and the steam-water heat exchanger ensure the temperature of the heating outlet water. The workflow is as follows: 30℃ heating return water enters each waste heat recovery unit of the second centralized peak shaving energy station 22 and is heated to 84.5℃ before entering the second centralized peak shaving energy station 22. Steam is provided by the coal gasification integrated gas boiler 221 to drive the steam turbine to drive the steam-driven heat pump 222 to heat to 92℃. The exhaust steam of the steam turbine serves as a peak guarantee heat source, heating part of the water to 95℃ and flowing into the third heating network transmission system 43, and another part of the water is heated to 105℃ and flowing into the second heating network transmission system 42. The remaining small portion of 30℃ heating return water is recycled through a type-I absorption heat pump and flash compression device 224 to recover 55℃ waste hot water or 40℃ return water supplied by the first centralized peak shaving energy station 21. The waste hot water is heated to 105℃, and the driving heat source is the 4MPa extraction steam from the steam turbine.

[0053] It should be noted that the centralized peak-shaving energy station 2, as the core peak-shaving unit of the system, uses equipment such as the gas-fired boiler 221 and the steam-driven heat pump 222 to reheat the waste heat recovered from distributed sources, meeting peak heating demands. It integrates steam, gas, and electricity as driving methods to achieve complementary heat sources; for example, steam turbine extraction drives the steam-type absorption heat pump 223, and the exhaust steam is used for peak heating, improving energy utilization. Through flash compression devices 224 and steam-water heat exchangers, the outlet water temperature is ensured to remain stable at 95℃~105℃, adapting to different heating network requirements.

[0054] The regional base heat source power plant 3 provides stable 105℃ high-temperature hot water as the system's base heat source, ensuring heating safety under extreme conditions; it is linked with the centralized peak-shaving energy station 2 through heat pipelines to achieve dynamic matching of base load and peak load, reducing overall energy consumption.

[0055] The first distributed waste heat recovery energy station 11 includes a tenth waste heat recovery unit 111, an eleventh waste heat recovery unit 112, and a twelfth waste heat recovery unit 113, while the second distributed waste heat recovery energy station group 12 includes a first waste heat recovery unit 121, a second waste heat recovery unit 122, a third waste heat recovery unit 123, a fourth waste heat recovery unit 124, a fifth waste heat recovery unit 125, a sixth waste heat recovery unit 126, a seventh waste heat recovery unit 127, an eighth waste heat recovery unit 128, and a ninth waste heat recovery unit 129.

[0056] like Figure 4 As shown, the working principle of the first waste heat recovery unit 121 is as follows: First, primary heating is performed: the 30℃ municipal heating return water exchanges heat with the 80℃ waste heat through the plate heat exchanger 10, raising the return water temperature to 80℃. Simultaneously, the 80℃ waste heat is cooled to 35℃ and connected to the 35℃ waste hot water return pipe, and the 120℃ condensate supply water is cooled to 85℃ and connected to the 85℃ condensate return pipe. Secondary heating is then performed: the heated 80℃ hot water is fed into the absorber of the first-stage Class II absorption heat pump, using the 65℃ heat source provided by the centrifugal heat pump 20 as the driving heat source for the first temperature recovery. The temperature is increased to 85℃; finally, a third-stage heating process is performed: the 85℃ hot water is fed into the absorber of the second-stage Class II absorption heat pump for a second temperature increase, ultimately outputting 90℃ hot water, which is then transported to the second centralized peak-shaving heat source station; during the second and third-stage heating processes, 34℃ waste heat is fed into the generator of absorption heat pump 30 to cool down to 30℃ and then returned to the 30℃ waste hot water return pipe, and 50℃ waste heat is fed into centrifugal heat pump 20 to gradually cool down to 42.7℃ and then fed into absorption heat pump 30 to gradually cool down to 35℃ before connecting to the 35℃ waste hot water return pipe.

[0057] It should be noted that the first waste heat recovery unit 121 employs a three-stage heating process, utilizing a combination of plate heat exchanger 10, a type II absorption heat pump, and a centrifugal heat pump 20 to gradually raise the temperature of the 30℃ municipal heating return water, ultimately outputting 90℃ hot water. Simultaneously, waste heat at different temperatures is effectively recovered and utilized; for example, 80℃ waste heat is cooled to 35℃ and connected to the waste hot water return pipe, and 120℃ condensate supply water is cooled to 85℃ and connected to the condensate return pipe, thus improving the overall energy utilization efficiency. During the two-stage and three-stage heating processes, the 65℃ heat source provided by the centrifugal heat pump 20 is used as the driving heat source, enabling the efficient operation of the absorption heat pump. Furthermore, through the rational design of the heat pump connections and operating methods, waste heat at different temperatures can work together, improving the overall performance of the system.

[0058] like Figure 5As shown, the working principle of the second waste heat recovery unit 122 is as follows: First, primary heating is performed: the 30℃ municipal heating return water exchanges heat with the 83℃ waste heat through the plate heat exchanger 10, raising the return water temperature to 81℃. Simultaneously, the 83℃ waste heat is cooled to 35℃ and connected to the 35℃ waste hot water return pipe. Then, secondary to tertiary heating is performed: the 81℃ municipal heated water undergoes a stepped temperature increase through the centrifugal heat pump 20 condenser and the secondary absorption heat pump absorber, ultimately reaching 94℃ before being collected and transported to the second centralized peak-shaving energy station 22. Simultaneously, the 8℃ cold source water is heated to 15℃ through the secondary absorption heat pump condenser and then collected and transported to... The open-type cold source tower cools the water to 8°C and then returns it to the condensers of each absorption heat pump 30 to form a cycle; the 36°C waste water is cooled to 33°C by the second-class absorption heat pump generator and then connected to the 33°C waste water return pipe; the 50°C waste water is cooled step by step by five centrifugal heat pump 20 evaporators to 35°C and then returns to the 35°C waste heat protection plate heat exchanger 50; at the same time, the centrifugal heat pump 20 condenser end can generate the medium-temperature driving heat source required by the corresponding absorption heat pump 30 evaporator end, with a temperature range of 66~76°C. In this way, the centrifugal heat pump 20 and the absorption heat pump 30 are coupled, improving the system operating efficiency.

[0059] It should be noted that the second waste heat recovery unit 122 achieves a stepped temperature increase of municipal heated water from 81℃ to 94℃ through the centrifugal heat pump 20 condenser and the type II absorption heat pump absorber. Simultaneously, it utilizes the type II absorption heat pump condenser to heat and recycle the cold source water, and cools the waste hot water through the centrifugal heat pump 20 evaporator and the type II absorption heat pump generator. This stepped heating and heat pump coupling method fully utilizes the characteristics of different heat pumps, achieving efficient energy conversion and utilization. The centrifugal heat pump 20 condenser can generate the medium-temperature driving heat source required by the absorption heat pump 30 evaporator, with a temperature range of 66-76℃, realizing the coupling of the centrifugal heat pump 20 and the absorption heat pump 30, improving system operating efficiency and reducing energy waste.

[0060] like Figure 6 As shown, the working principle of the third waste heat recovery unit 123 is as follows: First, primary heating is performed: a portion of the 30℃ municipal heating return water exchanges heat with 62.5℃ waste heat through a plate heat exchanger 10, raising the return water temperature to 60℃; simultaneously, it exchanges heat with 80℃ waste heat through another plate heat exchanger 10, raising the remaining 30℃ municipal return water temperature to 75℃; then, secondary to tertiary heating is performed: the 60℃ and 75℃ municipal hot water heated by the plate heat exchanger 10 are heated in stages according to temperature, and then passed through three types of absorption heat pump absorbers to achieve stepped heating, finally reaching 91℃ before being collected and transported to the second centralized peak-shaving energy station 22; the 10℃ cold source water is heated to 18℃ through the three types of absorption heat pump condensers, collected and transported to the open cold source tower to cool to 8℃ before returning to the condensers of each absorption heat pump 30 to form a cycle.

[0061] It should be noted that in the third waste heat recovery unit 123, waste heat at different temperatures (62.5℃ and 80℃) is used to exchange heat with a portion of the 30℃ municipal heating return water. Then, through three types of absorption heat pump absorbers, the water is gradually heated to 91℃. This multi-heat-source, staged heating method allows for rational utilization of waste heat based on its temperature characteristics, improving energy efficiency. The 10℃ chilled water is heated to 18℃ by the three types of absorption heat pump condensers, then collected and transported to an open-type cold source tower to cool to 8℃ before returning to the individual absorption heat pump condensers to form a cycle. This achieves the recycling of chilled water and reduces water consumption.

[0062] Absorption heat pumps 30 are mainly divided into three categories based on their working principle and temperature rise method: The first type (heating type) uses high-temperature driving heat to raise low-temperature waste heat to a medium temperature; the second type (heating type) uses medium-temperature driving heat to upgrade some low-temperature heat to a high temperature, suitable for industrial processes requiring high-temperature heat sources; the third type (combined type) combines the characteristics of the first two types to achieve multi-temperature heat output, suitable for complex heating needs. In this system, these three types of heat pumps work together: the first type recovers low-temperature waste heat for heating, the second type overcomes temperature bottlenecks to produce process steam, and the third type achieves 105℃ hot water production during the non-heating season, thus improving the overall energy efficiency of the system and demonstrating the significant advantages of multi-stage heat pump coupling in the deep utilization of waste heat.

[0063] like Figure 7As shown, the working principle of the fourth waste heat recovery unit 124 is as follows: 30°C municipal water passes through a sludge separator and enters a water pump. After exiting the pump, it splits into two paths. One path leads to multiple first-group plate heat exchangers 10, where it exchanges heat with 80°C high-temperature liquid to form 78°C municipal high-temperature water. The other path outputs two branches. One branch leads the 30°C municipal water to the third-group plate heat exchanger 10 to form 48°C municipal high-temperature water. This 48°C municipal high-temperature water is then introduced into the condensers of seven centrifugal heat pumps 20 connected in series. Simultaneously, the other branch supplies 30°C municipal water to the economizers of the seven centrifugal heat pumps 20. The municipal water passing through the economizer cools the compressors in the centrifugal heat pumps 20, resulting in initial temperature increases during this process. Then it is mixed with the municipal water flowing out of the condenser and then enters the evaporator for reheating; wherein, the 48°C municipal high-temperature water flowing out of the third set of plate heat exchangers 10 becomes 78°C municipal high-temperature water after passing through the first 5 sets of centrifugal heat pumps 20. At this time, it is mixed with the 78°C municipal high-temperature water after heat exchange with the first set of plate heat exchangers 10 and then enters the condensers of the 6th and 7th sets of centrifugal heat pumps 20 in sequence. If the temperature reaches the preset temperature, the 6th and 7th sets of centrifugal heat pumps 20 will not work. If the temperature does not reach the required temperature, it will continue to be heated when passing through the 6th and 7th sets of centrifugal heat pumps 20. The municipal water after heating becomes 89°C municipal high-temperature water.

[0064] It should be noted that in the fourth waste heat recovery unit 124, the 30°C municipal water enters the water pump after passing through the sludge separator. After exiting the pump, it splits into two streams. One stream exchanges heat with the 80°C high-temperature liquid through multiple first-group plate heat exchangers 10. The other stream exchanges heat and raises the temperature through the condensers and economizers of the third-group plate heat exchangers 10 and the 7th group centrifugal heat pumps 20. This complex heat exchange process design fully considers the heat transfer between water flows of different temperatures and flow rates, achieving effective heating of the municipal water. By combining different groups of plate heat exchangers 10 and centrifugal heat pumps 20, and by determining whether the 6th and 7th groups of centrifugal heat pumps 20 operate based on temperature conditions, flexible control of the outlet water temperature is achieved, meeting diverse heating needs.

[0065] like Figure 8As shown, the working principle of the fifth waste heat recovery unit 125 is as follows: The 30℃ municipal heating return water is divided into two paths. The first path is further divided into a first branch and a second branch, and the second path is divided into a third branch and a fourth branch. The 30℃ municipal heating return water in the first branch exchanges heat with the first set of plate heat exchangers 10 and is heated to 62℃. Then, it passes through the condensers of four sets of magnetic levitation centrifugal heat pumps 40 and is gradually heated to 83.7℃. At the same time, the 30℃ municipal heating return water in the second branch enters the economizers of the four sets of magnetic levitation centrifugal heat pumps 40 to ensure that each set... The heat exchange effect of the magnetic levitation centrifugal heat pump 40; similarly, the 30℃ municipal heating return water from the third branch exchanges heat with the second set of plate heat exchangers 10 and is heated to 44℃, then passes through the condensers of the six sets of magnetic levitation centrifugal heat pumps 40 in stages, gradually increasing the temperature to 80.9℃. Simultaneously, the 30℃ municipal heating return water from the fourth branch enters the economizers of the six sets of magnetic levitation centrifugal heat pumps 40, ensuring the heat exchange effect of each set of magnetic levitation centrifugal heat pumps 40. In the above process, the 45.8℃ hot water return water is divided into two paths, one of which passes through the condensers of the six sets of magnetic levitation centrifugal heat pumps 40 in stages. The last three magnetic levitation centrifugal heat pumps in the group 40 cool the water to 35℃ via evaporator heat exchange. Another stream of water cools to 42.3℃ via evaporator heat exchange in the last three magnetic levitation centrifugal heat pumps in the group 40, then to 35℃ via the third plate heat exchanger 10. The water cooled to 42.3℃ then cools to 39℃ via evaporator heat exchange in the first three magnetic levitation centrifugal heat pumps in the group 40, before being mixed with the water that has passed through the second plate heat exchanger 10. The water cooled to 35°C by heat exchanger 10 is converted into 38.5°C water. The 38.5°C water is then cooled to 35°C by the evaporator of the first of the four magnetic levitation centrifugal heat pumps 40. The two 35°C water streams are connected to the 35°C hot water supply pipe. At the same time, the 64.2°C hot water return water is cooled to 35°C by the first plate heat exchanger 10 and then connected to the 35°C hot water supply pipe. The cooling tower water supply is connected to the cooling tower return water pipe after being cooled by the protective plate heat exchanger 50.

[0066] It should be noted that in the fifth waste heat recovery unit 125, the 30℃ municipal heating return water is divided into two paths, each of which is further divided into branches. These branches are used for waste heat recovery and heating through the condenser and economizer of the plate heat exchanger 10 and the magnetic levitation centrifugal heat pump 40, respectively. This multi-branch design can make full use of waste heat resources in different locations and improve the efficiency of waste heat recovery. The 45.8℃ and 64.2℃ hot water return water and waste hot water at different temperatures are reasonably cooled and connected. For example, the 45.8℃ hot water return water is divided into two paths, which are cooled by heat exchange in the evaporator of the magnetic levitation centrifugal heat pump 40 and then connected to the 35℃ hot water supply pipe. The 64.2℃ hot water return water is cooled by heat exchange in the plate heat exchanger 10 and then connected to the 35℃ hot water supply pipe. This ensures the stable operation of the system and the effective use of energy.

[0067] like Figure 9 As shown, the working principle of the sixth waste heat recovery unit 126 is as follows: The 30℃ municipal heating return water is divided into two paths. One path is heated to 82.7℃ via the first set of plate heat exchangers 10. The other path is divided into two branches. One branch is heated to 61℃ via the second set of plate heat exchangers 10, and the other branch is heated to 48℃ via the third set of plate heat exchangers 10. Then, the water passes through the condensers of the first and second sets of magnetic levitation centrifugal heat pumps 40 to reach 59.5℃. The water at 59.9℃ is mixed with the water at 61℃ and then passed through the condensers of the third, fourth, fifth, sixth, and seventh sets of magnetic levitation centrifugal heat pumps 40, gradually increasing the temperature to 90℃. The water at 90℃ is mixed with the water at 82.7℃ and connected to the 90℃ municipal water supply pipe. The 30℃ municipal heating return water enters the economizers of each group of magnetic levitation centrifugal heat pumps 40 to ensure the heat exchange effect of each group of magnetic levitation centrifugal heat pumps 40. In the above process, the 80℃ waste hot water passes through the first group of plate heat exchangers 10, the second group of backup plate heat exchangers 50, and the first group of backup plate heat exchangers 50 in sequence to be cooled down to 35℃ before being connected to the 35℃ waste hot water pipe. The circulating cooling water enters the first group of backup plate heat exchangers 50 and the second group of backup plate heat exchangers 50 respectively for heat exchange and temperature increase before entering the cooling tower. The 50℃ waste hot water first passes through the evaporator of the sixth group of magnetic levitation centrifugal heat pumps 40 for heat exchange. The water temperature reaches 46.2℃, then passes through the evaporators of the fifth and sixth magnetic levitation centrifugal heat pumps 40 to exchange heat to 40.6℃. Next, it passes through the evaporators of the third, second, and first magnetic levitation centrifugal heat pumps 40 to exchange heat to 35℃ before entering the second protective plate heat exchanger 50. In case of unstable return water, the protective plate heat exchanger 50 is activated to ensure a low-temperature return water of 35℃. The 40℃ waste hot water passes through the evaporator of the seventh magnetic levitation centrifugal heat pump 40 to exchange heat to 34℃ before being connected to the 34℃ waste hot water pipe.

[0068] It should be noted that in the sixth waste heat recovery unit 126, the 30℃ municipal heating return water is divided into two paths. One path is heated by heat exchange through the first set of plate heat exchangers 10, while the other path is divided into two branches, which are heated by heat exchange through the second and third sets of plate heat exchangers 10 respectively, and then successively heated to 90℃ through the condensers of multiple sets of magnetic levitation centrifugal heat pumps 40. This combination of multi-stage plate heat exchangers 10 and magnetic levitation centrifugal heat pumps 40 can fully utilize the advantages of different equipment to achieve efficient heating of municipal heating return water. Reasonable cooling and connection treatments are implemented for the 80℃, 50℃, and 40℃ waste hot water and circulating cooling water. For example, the 80℃ waste hot water is cooled to 35℃ by passing through the plate heat exchangers 10 and the protective plate heat exchangers 50 before being connected to the 35℃ waste hot water pipe. The circulating cooling water enters the protective plate heat exchangers 50 for heat exchange and is then heated before entering the cooling tower, ensuring the energy balance and stable operation of the system.

[0069] like Figure 10 As shown, the working principle of the seventh waste heat recovery unit 127 is as follows: First-stage heating: The first set of plate heat exchangers 10 uses the waste heat of the 80℃ circulating cooling water as a heat source to raise the temperature of the municipal 30℃ return water to 65.8℃; Second to seventh-stage heating: The 65.8℃ municipal hot water is heated in stages through the centrifugal heat pump 20 condenser and the third-stage absorption heat pump absorber, finally reaching 85℃ before entering the next stage; Eighth-stage heating: The 85℃ municipal hot water is heated to 10℃ through a first-stage absorption heat pump. After reaching 0℃, the water is collected and transported to the second centralized peak-shaving heat source station. At the same time, the 8℃ cold source water is heated to 15℃ through the three types of absorption heat pump condensers, collected and transported to the open cold source tower to cool down to 8℃, and then returned to the 30 condensers of each absorption heat pump to form a cycle. The 40℃ waste hot water is cooled to 32℃ through the two types of absorption heat pump generators and then returned to the cooling tower. The 50℃ waste hot water is cooled step by step through 6 sets of centrifugal heat pump evaporators to 35℃ and then returned to the waste heat protection plate heat exchanger.

[0070] It should be noted that in the seventh waste heat recovery unit 127, the primary heating utilizes the waste heat of the 80℃ circulating cooling water to raise the municipal 30℃ return water to 65.8℃. Then, through the centrifugal heat pump 20 condenser and the three types of absorption heat pump absorbers, the water undergoes a second to seventh stage of temperature increase. Finally, it is heated to 100℃ by a first-class absorption heat pump. This multi-stage heating and heat pump synergy fully utilizes the heat from different heat sources, improving energy efficiency. The 8℃ cold source water is heated to 15℃ through the three types of absorption heat pump condensers, then collected and transported to the open-type cold source tower for cooling to 8℃ before returning to the respective absorption heat pump 30 condensers to form a cycle. The 40℃ and 50℃ waste water is cooled step-by-step through the corresponding heat pump evaporators before returning to the waste heat protection plate heat exchanger or cooling tower, achieving the recycling of cold source water and waste water and reducing energy waste.

[0071] like Figure 11As shown, the eighth waste heat recovery unit 128 effectively reduces load and frequency through the magnetic levitation centrifugal heat pump 40 and its control system. A protective plate heat exchanger 50 is installed; when the return water is unstable, the protective plate heat exchanger 50 is activated to ensure a low-temperature return water of 35℃, meeting the factory's return water requirements. A main pipeline is installed to promptly reduce some of the temperature rise. By separately supplying low-temperature return water to the economizer of the magnetic levitation centrifugal heat pump 40, the system addresses the surge and shutdown issues caused by the difficulty of frequency conversion of ordinary centrifugal chillers due to low-temperature heat sources when municipal return water is unstable or insufficient. The specific working principle is as follows: Water from the 59.4℃ supply pipe is cooled to 40℃ by the fourth set of plate heat exchangers 10 and then enters the 40℃ return pipe, repeating this cycle. This cycle is also combined with the 90℃ condensate according to seasonal changes. Water from the 50℃ supply pipe is cooled to 42℃ by the third set of plate heat exchangers 10, and then enters the evaporators of the first and second sets of centrifugal heat pumps 20 to be cooled to 35℃. After being kept warm in the second set of plate heat exchangers 10, it enters the 35℃ return pipe. The return water pipe circulates in this manner; the 48°C water output from the 50°C supply pipe is cooled to 44.3°C by the evaporator of the first-stage centrifugal heat pump 20, then cooled to 40°C by the evaporator of the second-stage centrifugal heat pump 20 before entering the 42°C return water pipe, and this cycle repeats; the water output from the 40°C supply pipe is cooled to 32°C by the first set of plate heat exchangers 10 before entering the 32°C return water pipe, and this cycle repeats; the water output from the 80°C supply pipe is cooled to 32°C by the first set of absorption heat pumps 3... The evaporator at 0°C cools to 69°C, then the evaporator at the second absorption heat pump 30 cools to 58°C. It then sequentially passes through the evaporators at the first, second, third, and fourth centrifugal heat pumps 20, cooling to 42°C before entering the 35°C return water pipe. The water cools by 4°C with each centrifugal heat pump 20 it passes through. The cooling water from the 32°C cooling water supply pipe passes through the second plate heat exchanger 10. After heat exchange to 40℃, the water enters the 40℃ cooling water return pipe, and the cycle repeats. The 250℃, 1.5MPa steam output from the steam inlet pipe is converted into 173℃, 0.85MPa steam after passing through the desuperheating and pressure reducing device. It then enters the generators of the first and second absorption heat pumps 30 and is cooled to 90℃ condensate. The 90℃ condensate in the condensate pipe is connected to the 59.4℃ supply water pipe during the heating season and to the 40℃ return water pipe during the non-heating season. Part of the water from the 30℃ municipal return pipe exchanges heat with the water from the 40℃ supply pipe in the first plate heat exchanger 10 to reach 38℃, then exchanges heat with the water from the 59.4℃ supply pipe in the fourth plate heat exchanger 10 to reach 57.4℃. Another part of the 30℃ municipal return water exchanges heat with the water from the 50℃ supply pipe in the third plate heat exchanger 10 to reach 47℃, then enters the condenser of the first centrifugal heat pump 20 to reach 53.9℃, then enters the condenser of the second centrifugal heat pump 20 to reach 60.5℃, where it mixes with the 57.4℃ heating water to reach 59℃. The water is sequentially heated to 86.4℃ in the condenser of the first-stage centrifugal heat pump 20 and then enters the municipal water supply pipe at 88.2℃. Alternatively, the water output from the 30℃ municipal return pipe can be heated to 36.8℃ by exchanging heat with the water output from the 40℃ supply pipe through the first set of plate heat exchangers 10, and then to 45.5℃ by exchanging heat with the water output from the 50℃ supply pipe through the third set of plate heat exchangers 10. The water then sequentially enters the condensers of the first set of centrifugal heat pumps 20, the second set of centrifugal heat pumps 20, the second-stage centrifugal heat pump 20, and the first-stage centrifugal heat pump 20 and then to 88.7℃ before entering the municipal water supply pipe at 88.2℃. The water output from the 85℃ process hot water return pipe is heated to 95℃ by the absorbers of the first and second absorption heat pumps 30, and then heated to 105℃ by the condensers of the first and second absorption heat pumps 30, before entering the 105℃ process hot water supply pipe. This cycle repeats continuously. The heated hot water output from the 85℃ heat tracing return pipe is heated to 90℃ by the condensers of the first, second, third, and fourth centrifugal heat pumps 20, before entering the 90℃ heat tracing supply pipe.

[0072] It should be noted that the eighth waste heat recovery unit 128, through the magnetic levitation centrifugal heat pump 40 and control system, can achieve excellent load reduction and frequency reduction, and is equipped with a protective plate heat exchanger 50. When the return water is unstable, switching to the protective plate heat exchanger 50 can ensure a low-temperature return water of 35℃. This solves the problem of surge shutdown caused by the difficulty of frequency conversion of ordinary centrifugal chillers due to low-temperature heat sources when the municipal return water is unstable or insufficient. The water output from the supply and return water pipes at different temperatures such as 59.4℃, 50℃, 40℃, and 80℃ undergoes complex heat exchange, cooling, heating, and mixing processes. For example, the water output from the 50℃ supply water pipe enters the evaporator of the centrifugal heat pump 20 for cooling after heat exchange in the plate heat exchanger 10, and then mixes with water that has undergone other treatments before entering the next stage of treatment. This achieves the rational utilization and heat transfer of water flows at different temperatures.

[0073] like Figure 12As shown, the working principle of the ninth waste heat recovery unit 129 is as follows: 50℃ waste water is cooled to 46.25℃ by the fourth centrifugal heat pump 20, then cooled to 42.5℃ by the third centrifugal heat pump 20, then cooled to 38.75℃ by the second centrifugal heat pump 20, and finally cooled to 35℃ by the first centrifugal heat pump 20 before entering the 35℃ hot water supply pipe; 80℃ waste water is cooled to 35℃ by the plate heat exchanger 10 before entering the 35℃ hot water supply pipe; 30℃ heating water is heated to 60℃ by the plate heat exchanger 10, then successively heated to 66.5℃ by the first centrifugal heat pump 20, then cooled to 72.5℃ by the second centrifugal heat pump 20, then heated to 78.5℃ by the third centrifugal heat pump 20, and finally heated to 85℃ by the fourth centrifugal heat pump 20 before entering the 85℃ hot water supply pipe.

[0074] It should be noted that the ninth waste heat recovery unit 129 cools the waste water at 50℃ and 80℃ respectively through a centrifugal heat pump 20 and a plate heat exchanger 10 before connecting it to the 35℃ hot water supply pipe. Simultaneously, the 30℃ heating water supply is heated in stages to 85℃ through the plate heat exchanger 10 and multiple centrifugal heat pumps 20 before entering the hot water supply pipe. This staged treatment method for waste water and heating water allows for rational utilization based on different water temperature characteristics, improving energy efficiency.

[0075] like Figure 13 As shown, the working principle of the tenth waste heat recovery unit 111 is as follows: Water at 35℃ output from the 35℃ protection plate heat exchanger 50 is heated to 72℃ by the first set of plate heat exchangers 10 and then enters the 72℃ return water pipe; water at 30℃ output from the municipal water return pipe is heated to 70℃ by the first set of plate heat exchangers 10, then heated to 82℃ by the centrifugal heat pump 20, while another stream is heated to 48℃ by the second set of plate heat exchangers 10, then heated to 82℃ by the third set of plate heat exchangers 10. The two streams of 82℃ water are mixed and enter the first set of centrifugal heat pumps 20, where they are heated to 86℃, then enter the coupled heat pump group 60, where they are heated to 95℃ before entering the municipal water supply pipe; simultaneously, cooling water at 11℃ output from the cooling tower return water pipe is heated to 16℃ by the coupled heat pump group 60 before entering the cooling tower supply water pipe. Water at 36.6℃ from the 38.6℃ return water pipe passes through the first and second centrifugal heat pumps 20, and is then output at 31℃ before entering the 32℃ supply water pipe. Water at 50℃ from the 50℃ return water pipe first passes through the coupled heat pump group 60 to cool to 39℃, then passes through the second centrifugal heat pump 20 to cool to 37℃, and then passes directly through the second plate heat exchanger 10 to cool to 35℃. The two streams of water mix to form water at 36.5℃, which enters the supply water pipe of the 35℃ protection plate heat exchanger 50. Water at 84.65℃ from the 85℃ return water pipe passes through the third plate heat exchanger 10 to cool to 50℃ before entering the supply water pipe of the 50℃ protection plate heat exchanger 50.

[0076] It should be noted that the water from different heat sources in the tenth waste heat recovery unit 111—35℃ water from the 35℃ supply pipe of the 35℃ plate heat exchanger, 30℃ water from the municipal water return pipe, 11℃ cooling water from the cooling tower return pipe, and 50℃ water from the 50℃ return pipe—undergoes complex heat exchange and heating processes through the first and second sets of plate heat exchangers 10, centrifugal heat pumps 20, and coupled heat pump groups 60, ultimately raising the municipal water temperature to 95℃ before it enters the municipal water supply pipe. This multi-heat source integration and heating method can fully utilize various available heat sources and improve the overall energy utilization efficiency.

[0077] like Figure 14 and Figure 15 As shown, the coupled heat pump unit 60 consists of five cylindrical coupling units, including a first type coupling unit 601, a second type coupling unit 602, and a third type coupling unit 603. The first type coupling unit 601 includes a coupled heat exchanger 6011 and an absorber 6012 arranged vertically. The second type coupling unit 602 includes a condenser 6021 and a generator 6022 arranged vertically. The third type coupling unit 603 includes a first evaporator 6031 and a second evaporator 6032 arranged vertically. The five coupling units are connected by pipes to form two coupled heat exchange units in series. Each coupled heat exchange unit includes the third type coupling unit 603, the first type coupling unit 601, and the second type coupling unit 602 connected in sequence, and the two units share the same third type coupling unit 603.

[0078] The inlet of condenser 6021 is directly connected to either heating water inlet pipe 606 or cooling water inlet pipe, and its outlet is connected to the corresponding outlet pipe; the inlet of generator 6022 is connected to circulating water inlet pipe 604, and its outlet is connected to circulating water outlet pipe 605; the inlet of absorber 6012 is connected to heating water inlet pipe 606, and its outlet is connected to heating water outlet pipe 607; the inlet of refrigerant passage of coupling heat exchanger 6011 is connected to refrigerant supply pipe 608, and its outlet is connected to refrigerant return pipe 609.

[0079] The coupling heat exchanger 6011 and the condenser 6021 are connected by a liquid working fluid transfer pipe 6010; the coupling heat exchanger 6011 and the absorber 6012 are connected by a gas working fluid transfer pipe 6020; and a bidirectional lithium bromide solution circulation pipe 6030 is provided between the absorber 6012 and the generator 6022.

[0080] It should be noted that the coupled heat pump unit 60 is used to further heat the water. The coupled heat pump unit 60 is composed of different types of coupling machines, which are connected by pipelines to form a coupled heat exchange unit, realizing efficient heat transfer and conversion, and providing strong support for the system's heating.

[0081] Five coupling machines are connected by pipes to form two series-connected coupled heat exchange units. Each coupled heat exchange unit contains a third-type coupling machine 603, a first-type coupling machine 601, and a second-type coupling machine 602 connected in sequence, with both units sharing the same third-type coupling machine 603. This ingenious pipe connection method enables heat transfer and coordinated operation between different coupling machines, improving the overall performance and energy efficiency of the heat pump unit. Circulating water enters the generator 6022 through the circulating water inlet pipe 604, releasing heat to heat the dilute lithium bromide solution. The water vapor enters the condenser 6021 and is cooled by cooling water or heating return water. The heat released during condensation is absorbed, and the liquid water flows into the coupled heat exchanger 6011, then into the evaporator of the third-type coupling machine 603 to evaporate and absorb heat from the external heat source. The vapor returns to the absorber 6012 to be absorbed by the concentrated lithium bromide solution. The heat released during absorption is carried away by the heating water, and the dilute solution is pumped back to the generator 6022 to complete the cycle. The entire process achieves efficient heat transfer and conversion between different components, improving energy utilization efficiency. The high-temperature water heated by the absorber 6012 can be used directly for heating, while the cooling water heated by the condenser 6021 can also serve as an auxiliary heat source. The first evaporator 6031 and the second evaporator 6032 absorb low-temperature heat sources and can simultaneously provide cooling functions. This multi-functional output design enables the coupled heat pump unit to meet different heating and cooling needs, improving the versatility and practicality of the equipment.

[0082] like Figure 16 As shown, the working principle of the coupled heat pump unit 60 is as follows: Circulating water, such as industrial waste hot water, enters the generator 6022 through the circulating water inlet pipe 604. The circulating water releases heat to heat the dilute lithium bromide solution inside, causing the water in it to evaporate and form water vapor, which then enters the condenser 6021 through the gas phase working fluid transfer pipe 6020. The cooled circulating water is discharged from the circulating water outlet pipe 605, completing the heat release process.

[0083] After water vapor enters the condenser 6021, it is cooled by external cooling water or heating return water. The cooling water or heating water enters through the inlet end of the condenser 6021. During the cooling process, the water vapor condenses into liquid water. The heat released by the condensation is absorbed by the cooling water or heating water, causing its temperature to rise. Then it is output from the outlet end of the condenser 6021 and can be used for heating or cooling tower circulation. The liquid water flows into the coupling heat exchanger 6011 through the liquid phase working fluid transfer pipe 6010.

[0084] Liquid refrigerant enters the first evaporator 6031 and the second evaporator 6032 of the third type coupling machine 603 from the coupling heat exchanger 6011, evaporates under low pressure, and absorbs heat from external heat sources, such as low-temperature waste heat, in the process. The evaporated refrigerant vapor returns to the absorber 6012 through the gas phase working fluid transfer pipe 6020.

[0085] Refrigerant vapor enters absorber 6012 and is absorbed by concentrated lithium bromide solution from generator 6022. This concentrated lithium bromide solution is transported through lithium bromide solution circulation pipe 6030, forming a dilute solution after absorption. The heat released during the absorption process is carried away by low-temperature water input through heating water inlet pipe 606, and after being heated, it is output from heating water outlet pipe 607 for heating. The dilute solution is pumped back to generator 6022 through lithium bromide solution circulation pipe 6032, thus completing the entire circulation process.

[0086] The refrigerant supply line 608 supplies low-temperature refrigerant to the coupling heat exchanger 6011. After absorbing the cooling capacity of the evaporator in the coupling heat exchanger 6011, the low-temperature refrigerant returns to the external system through the refrigerant return line 609, thereby realizing the refrigeration or low-temperature heat recovery function.

[0087] Heating water output: The high-temperature water heated by the absorber 6012 can be directly used for heating through the heating water outlet pipe 607; the cooling water heated by the condenser 6021 can also be used as an auxiliary heat source; the first evaporator 6031 and the second evaporator 6032 absorb low-temperature heat sources and can provide cooling function at the same time.

[0088] like Figure 17 As shown, the working principle of the eleventh waste heat recovery unit 112 is as follows: Part of the 40°C water output from the 30°C municipal heating return pipe is heated to 48°C via the first set of plate heat exchangers 10, and then further heated to 55°C via the first set of centrifugal heat pumps 20; part of the 40°C water is heated to 55°C via the second and third sets of plate heat exchangers 10; the remaining 40°C water is first heated to 45°C via the second set of centrifugal heat pumps 20, then further heated to 58°C via the third set of centrifugal heat pumps 20, and finally heated to 55°C via the fourth set of centrifugal heat pumps 20; the three 55°C water streams are then heated to 55°C. After converging, the water enters the 55℃ municipal heating water supply pipe; simultaneously, the 80℃ water supply pipe outputs 80℃ water which is cooled to 42℃ by the second set of plate heat exchangers 10 and then enters the 40℃ protection plate heat exchanger 50; the 80℃ water supply pipe outputs 80℃ water which is cooled to 42℃ by the third set of plate heat exchangers 10 and then enters the 35℃ protection plate heat exchanger 50; the 40℃ water output from the 40℃ water supply pipe is cooled to 36℃ by the second set of centrifugal heat pumps 20, the third set of centrifugal heat pumps 20 and the fourth set of centrifugal heat pumps 20 respectively and then enters the 432℃ protection plate heat exchanger 50.

[0089] It should be noted that in the eleventh waste heat recovery unit 112, a portion of the 30℃ municipal heating return water is heated through different combinations of plate heat exchangers 10 and centrifugal heat pumps 20. For example, some 40℃ water is heated to 48℃ through the first set of plate heat exchangers 10, and then heated to 55℃ through the first set of centrifugal heat pumps 20; some 40℃ water is heated to 55℃ through the second and third sets of plate heat exchangers 10, and so on. This multi-path heating method can be flexibly adjusted according to actual conditions, improving the system's adaptability and energy utilization efficiency. Water from the 80℃ supply pipe is heated to 40℃ and 35℃ respectively after heat exchange through plate heat exchangers 10, achieving reasonable distribution and utilization of water at different temperatures and ensuring stable system operation.

[0090] like Figure 18 As shown, the working principle of the twelfth waste heat recovery unit 113 is as follows: 80℃ waste water is heated by the first set of plate heat exchangers 10, and the output water at 35℃ is connected to the protective plate heat exchanger 50; 50℃ waste water is heated by the second set of centrifugal heat pumps 20, and the output water at 44.7℃ is then heated by the first set of centrifugal heat pumps 20, and the output water at 39.4℃ is connected to the protective plate heat exchanger 50; 38℃ waste water is heated by the second set of plate heat exchangers 10, and the output water at 32℃ enters the cooling tower. Simultaneously, the 38℃ water is further cooled to 33℃ by the third, fourth, fifth, and sixth sets of centrifugal heat pumps 20. After reaching a certain temperature, the water also enters the cooling tower; simultaneously, a portion of the 30℃ heating water return water is heated to 74.4℃ via the first set of plate heat exchangers 10, then to 79.7℃ via the first set of centrifugal heat pumps 20, and then to 85℃ via the second set of centrifugal heat pumps 20 before being connected to the heating water supply pipe; another portion of the 30℃ heating water return water is heated to 36℃ via the second set of plate heat exchangers 10, then to 40.75℃ via the third set of centrifugal heat pumps 20, then to 45.5℃ via the fourth set of centrifugal heat pumps 20, then to 50.25℃ via the fifth set of centrifugal heat pumps 20, and finally to 55℃ via the sixth set of centrifugal heat pumps 20 before being connected to the low-temperature heating water supply pipe.

[0091] It should be noted that the twelfth waste heat recovery unit 113 processes waste hot water at 80℃, 50℃, and 38℃, as well as 30℃ heating water return water, through plate heat exchangers 10 and centrifugal heat pumps 20 for heat exchange and temperature increase, respectively. For example, after the 80℃ waste hot water is heat-exchanged by the first set of plate heat exchangers 10, the output water temperature is 35℃, which is then connected to the backup plate heat exchanger. A portion of the 30℃ heating water return water is heat-exchanged by the first set of plate heat exchangers 10 to reach 74.4℃, and then further heated to 79.7℃ by the first set of centrifugal heat pumps 20. This comprehensive treatment method for waste hot water and heating water can fully utilize the heat of waste water, increase the temperature of heating water, and meet heating demand.

[0092] The three waste heat recovery units in the first centralized peak-shaving energy station 21 utilize waste heat for direct cascade heat exchange in the low-temperature section, while the high-temperature section uses three types of absorption heat pumps to gradually raise the temperature. To ensure the heating temperature, some absorption heat pumps use centrifugal heat pumps 20 as a preheating source. Among them, the absorption heat pump 30 uses a superconducting heat core heat pump, which is a circulation system that uses a low-grade heat source to pump heat from a low-temperature heat source to a high-temperature heat source. It is an effective device for recovering and utilizing low-temperature heat energy and has the dual functions of saving energy and protecting the environment. The superconducting heat core heat pump uses a corrugated plate heat exchanger, which changes the cross-sectional area of ​​the flow channel to continuously change the fluid dynamic pressure head, generating regular expansion and compression during the flow process, increasing the fluid Reynolds number, and achieving efficient heat exchange.

[0093] The waste heat recovery unit in the second centralized peak-shaving energy station 22 utilizes waste heat for direct cascade heat exchange in the low-temperature section, while the high-temperature section is heated step-by-step by a magnetic levitation centrifugal heat pump 40. For example... Figure 19 As shown, the magnetic levitation centrifugal heat pump 40 includes an evaporator 100, a condenser 200, and an economizer 300. The liquid working fluid enters the evaporator 100 through the inlet and exchanges heat inside. After the liquid working fluid becomes gaseous, it flows out of the evaporator 100 through the outlet. The gaseous working fluid first flows upward and is compressed by the primary compressor 400 and the secondary compressor 500, and then flows downward into the condenser 200, where it heats the heating water flowing into the condenser 200. After the heating water enters the condenser 200, it exchanges heat with the gaseous working fluid. The gaseous working fluid cools down to a liquid state and then enters the economizer 300. The heated heating water then flows out for heating. Since the temperature of the liquid working fluid entering the economizer 300 is still relatively high, in order to avoid wasting heat, some of the low-temperature heating water inside the condenser 200 will enter the economizer 300. The low-temperature heating water entering the economizer 300 will exchange heat with the liquid working fluid flowing through the economizer 300, further cooling the liquid working fluid. Meanwhile, this part of the low-temperature heating water will be heated and its temperature will rise, and it will cool the liquid working fluid a second time in the economizer 300. At the same time, it can also heat the low-temperature heating water, avoiding the waste of heat from the liquid working fluid, and the heating water can be used for heating again.

[0094] It should be noted that the magnetic levitation centrifugal heat pump 40 includes an evaporator 100, a condenser 200, and an economizer 300. The liquid working fluid enters the evaporator 100 through the inlet, undergoes heat exchange to become a gaseous working fluid, and is then compressed by a primary compressor 400 and a secondary compressor 500 before entering the condenser to heat the heating water. The cooled liquid working fluid then enters the economizer 300. Simultaneously, a portion of the low-temperature heating water inside the condenser 200 enters the economizer 300 to further cool the liquid working fluid and heat the low-temperature heating water. This unique internal structural design fully utilizes the heat from both the working fluid and the heating water, improving energy efficiency. The economizer 300 design allows a portion of the low-temperature heating water inside the condenser 200 to enter and further cool the liquid working fluid. Simultaneously, this portion of low-temperature heating water is heated, achieving secondary heat utilization and avoiding the waste of heat from the liquid working fluid. The heating water is then reused for heating, achieving energy savings.

[0095] like Figure 20 As shown, it also includes a main pipeline 70. The input and output ends of each magnetic levitation centrifugal heat pump 40 are connected to the main pipeline 70 through connecting branch pipes 80. A switching valve 90 is provided on the main pipeline 70 for each magnetic levitation centrifugal heat pump 40, and a switching valve 90 is also provided on the connecting branch pipes 80. When any magnetic levitation centrifugal heat pump 40 fails or the circulating water condition does not meet the requirements, the switching valve 90 on its connecting branch pipe 80 automatically closes, and the switching valve 90 on the corresponding main pipeline 70 automatically opens, and the water flows through the main pipeline 70 to the next magnetic levitation centrifugal heat pump 40; or when the municipal return water is insufficient, several switching valves 90 on the connecting branch pipes 80 are closed, and the switching valves 90 on the corresponding main pipeline 70 are opened, and the water flows through the main pipeline 70 for transportation.

[0096] It should be noted that the input and output ends of each magnetic levitation centrifugal heat pump 40 are connected to the main pipeline 70 via connecting branch pipes 80. A switching valve 90 is installed on the main pipeline 70 corresponding to each magnetic levitation centrifugal heat pump 40, and a switching valve 90 is also installed on the connecting branch pipes 80. When any magnetic levitation centrifugal heat pump 40 fails or the circulating water conditions do not meet requirements, the switching valve 90 on its connecting branch pipe 80 automatically closes, and the corresponding switching valve 90 on the main pipeline 70 automatically opens, allowing water to flow through the main pipeline 70 to the next magnetic levitation centrifugal heat pump 40. This design allows for rapid switching of the water flow path in case of equipment failure, ensuring continuous system operation and improving system reliability and stability. When municipal return water is insufficient, several switching valves 90 on the connecting branch pipes 80 are closed, and the corresponding switching valves 90 on the main pipeline 70 are opened, allowing water to flow through the main pipeline 70. This adjustment method allows for flexible adjustment of water flow distribution according to the actual situation of municipal return water, avoiding abnormal equipment operation due to insufficient return water and ensuring the normal operation of the system.

[0097] The first waste heat recovery unit 121, the second waste heat recovery unit 122, the third waste heat recovery unit 123, and the seventh waste heat recovery unit 127 in the second distributed waste heat recovery energy station group 12 are capable of producing process hot water at around 105°C during the non-heating season. This process hot water is either consumed locally within the circulation system or transported to the first station via the municipal hot water pipeline during the heating season, where it is used to produce steam through the flash compression device 224. The second centralized peak-shaving energy station 22 utilizes the high-temperature, high-pressure steam generated by the gas-fired boiler system to drive a steam turbine that in turn drives the flash compression device 224 to compress the flashed steam. Figure 21 As shown, during the non-heating season, one set of gas-fired boiler 221 is used to recover 105℃ process hot water to produce steam for economic analysis.

[0098] The first waste heat recovery unit 121, the second waste heat recovery unit 122, the third waste heat recovery unit 123, and the seventh waste heat recovery unit 127 in the second distributed waste heat recovery energy station group 12 are capable of producing process hot water at around 105°C during the non-heating season. This process hot water is either consumed locally within the circulation system or transported to the first station via the municipal hot water pipeline during the heating season to produce steam through the flash compression device 224. This design fully utilizes waste heat resources during the non-heating season, achieving comprehensive energy utilization throughout the year and improving energy economic efficiency. The second centralized peak-shaving energy station 22 uses high-temperature and high-pressure steam generated by a gas-fired boiler system to drive a steam turbine to drive the flash compression device 224 to compress the flashed steam. During the non-heating season, one gas-fired boiler 221 is operated to recover 105°C process hot water to produce steam for economic analysis. The economic analysis of producing steam from process hot water during the non-heating season provides a basis for the optimized operation and cost control of the system, and helps to improve the system's economy and sustainability.

[0099] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A cascade utilization system for chemical waste heat, characterized in that, include: The distributed waste heat recovery energy station group (1) includes multiple waste heat recovery units set up in multiple circulating water systems in industrial parks, which are used to extract and utilize process waste heat at different temperatures in stages. A centralized peak-shaving energy station (2) is connected to the distributed waste heat recovery energy station group (1) for peak-shaving heating of the recovered waste heat; The regional basic heat source power plant (3) is connected to the centralized peak-shaving energy station (2) through a heat pipeline to provide basic heat load; The heat network transmission system (4) includes a heat pipeline network connecting the centralized peak-shaving energy station (2) and the regional basic heat source power plant (3); The intelligent control system is used to dynamically regulate the heat distribution and operation of the distributed waste heat recovery energy station (1) and the centralized peak shaving energy station (2).

2. The chemical waste heat cascade utilization system according to claim 1, characterized in that: The distributed waste heat recovery energy station group (1) includes multiple sets of plate heat exchanger groups and multi-stage heat pump units connected in parallel. The multiple sets of plate heat exchanger groups are connected to waste heat sources at different temperature levels, and the multi-stage heat pump units receive hot water from different plate heat exchanger groups and perform cascade heating.

3. The chemical waste heat cascade utilization system according to claim 2, characterized in that: The heat pump unit adopts a series or parallel coupling arrangement, which includes a magnetic levitation centrifugal heat pump (40) and an absorption heat pump (30). The magnetic levitation centrifugal heat pump (40) is used for medium and high temperature heating, and the absorption heat pump (30) includes a type I absorption heat pump, a type II absorption heat pump and a type III absorption heat pump.

4. The chemical waste heat cascade utilization system according to claim 2, characterized in that: The distributed waste heat recovery energy station group (1) simultaneously processes at least two types of return water with different initial temperatures, sets an independent heating path for each type of return water, and outputs hot water of the same temperature after processing.

5. The chemical waste heat cascade utilization system according to claim 4, characterized in that: The distributed waste heat recovery energy station group (1) includes a first output pipeline and a second output pipeline. The first output pipeline is connected to the centralized peak-shaving energy station (2) and then directly connected to the heating network. The second output pipeline is connected to the heating network after being heated by the centralized peak-shaving energy station (2) and the regional basic heat source power plant (3) in sequence.

6. The chemical waste heat cascade utilization system according to claim 3, characterized in that: The distributed waste heat recovery energy station (1) also includes a waste heat protection system, which includes a plate heat exchanger (10) connected to the heat pump evaporator to maintain the minimum recovery temperature of the waste heat source.

7. The chemical waste heat cascade utilization system according to claim 2, characterized in that: The intelligent control system dynamically adjusts according to the return water temperature. When the return water temperature is detected to be higher than the first set value, the heat pump unit is started first to cool down; when the return water temperature is detected to be lower than the second set value, the plate heat exchanger group is used first for primary heating.

8. The chemical waste heat cascade utilization system according to claim 2, characterized in that: The distributed waste heat recovery energy station (1) includes a first waste heat recovery unit (121), a second waste heat recovery unit (122), a third waste heat recovery unit (123), a fourth waste heat recovery unit (124), a fifth waste heat recovery unit (125), a sixth waste heat recovery unit (126), a seventh waste heat recovery unit (127), an eighth waste heat recovery unit (128), a ninth waste heat recovery unit (129), a tenth waste heat recovery unit (111), an eleventh waste heat recovery unit (112), and a twelfth waste heat recovery unit (113); the first waste heat recovery unit (121) includes a plate heat exchanger (10), a centrifugal heat pump (20), and an absorption heat pump (30), which will convert the city heat into electricity. The municipal 30℃ return water is heated to 90℃ through a three-stage heating process; the second waste heat recovery unit (122) includes a plate heat exchanger (10), a centrifugal heat pump (20), and an absorption heat pump (30), which heats the municipal 30℃ return water to 94.4℃ through a five-stage heating process; the third waste heat recovery unit (123) includes a plate heat exchanger (10) and an absorption heat pump (30), which heats the municipal 30℃ return water to 91℃ through a six-stage heating process; the fourth waste heat recovery unit (124) includes a plate heat exchanger (10) and a magnetic levitation centrifugal heat pump (40), which heats the municipal 30℃ return water to 80℃ through a five-stage heating process; the fifth waste heat recovery unit (125) includes a plate heat exchanger (10) and a magnetic levitation centrifugal heat pump (40). Centrifugal heat pump (40) heats municipal 30°C return water to 80°C through five-stage heating; the sixth waste heat recovery unit (126) includes a plate heat exchanger (10) and a magnetic levitation centrifugal heat pump (40), which heats municipal 30°C return water to 80°C through six-stage heating; the seventh waste heat recovery unit (127) includes a plate heat exchanger (10), a centrifugal heat pump (20), and an absorption heat pump (30), which heats municipal 30°C return water to 100°C through eight-stage heating; the eighth waste heat recovery unit (128) includes a plate heat exchanger (10) and a magnetic levitation centrifugal heat pump (40), which heats municipal 30°C return water to 80°C through five-stage heating; the ninth waste heat recovery unit (129) includes a plate heat exchanger (10) and magnetic levitation centrifugal heat pump (40) heat the municipal 30℃ return water to 80℃ through five-stage heating; the tenth waste heat recovery unit (111) includes a plate heat exchanger (10) and magnetic levitation centrifugal heat pump (40), which heats the municipal 30℃ return water to 85℃ through four-stage heating; the eleventh waste heat recovery unit (112) includes a plate heat exchanger (10) and magnetic levitation centrifugal heat pump (40), which heats the 40℃ return water to 55℃ through the plate heat exchanger (10) and magnetic levitation centrifugal heat pump (40); the twelfth waste heat recovery unit (113) includes a plate heat exchanger (10) and magnetic levitation centrifugal heat pump (40), which heats the municipal 30℃ return water to 85℃ through four-stage heating.

9. The chemical waste heat cascade utilization system according to claim 1, characterized in that: The centralized peak-shaving energy station (2) includes a gas-fired boiler system and a steam-driven system. The steam-driven system includes a steam-driven heat pump (222), a steam-type absorption heat pump (223), and a flash compressor (224).

10. The chemical waste heat cascade utilization system according to claim 1, characterized in that: The heat network transmission system (4) includes a heating network for 105°C hot water, a heating network for 95°C hot water, and a return water network for 30°C hot water.

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