A water ring heat pump system for waste heat utilization of a carbon capture system

Abstract

This invention provides a water-loop heat pump system for waste heat utilization in carbon capture systems, mainly comprising an absorption tower, a flash tank, a regeneration tower, a first heat pump, a second heat pump, a third heat pump, a fourth heat pump, a steam heater, and a regeneration gas separator. This system integrates a multi-stage heat pump design, allowing the medium-to-high temperature waste heat recovered by the second and third heat pumps to serve as the driving heat source for the first heat pump or directly for preheating the rich liquid and the regenerated liquid at the bottom of the regeneration tower, forming a closed loop of internal energy cascade utilization. Simultaneously, by combining heat pump technology with the carbon capture process, adopting a mode of "waste heat driving heat pumps, heat pumps improving the waste heat grade before reusing it in the process," it efficiently recovers and upgrades the low-temperature waste heat generated in the carbon capture process, significantly reducing steam consumption in the regeneration stage, i.e., desorption energy consumption, thereby greatly improving the energy efficiency and economy of the entire carbon capture system.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and environmental protection technology, and specifically relates to a water-ring heat pump system for utilizing waste heat from carbon capture systems. Background Technology

[0002] Carbon dioxide (CO2) is one of the main greenhouse gases contributing to global warming, and the international community has widely reached a consensus on reducing carbon emissions. Against this backdrop, carbon capture technologies targeting gas sources such as vertical shaft furnace reducing gas, blast furnace gas, and industrial flue gas have been gradually promoted and applied. Among various capture processes, the organic amine chemical absorption method has become one of the commonly used CO2 capture methods in industry due to its high absorption efficiency and relatively mature technology. However, this method has significant drawbacks: the rich absorbent solution requires a large amount of heat energy during desorption and regeneration, resulting in high operating energy consumption; simultaneously, the organic amine solution is corrosive to equipment, and long-term use may affect system stability and production efficiency. Therefore, developing new, efficient, and low-energy-consumption CO2 capture processes has become an important research direction in this field, and economically feasible capture technologies are of great significance for achieving energy conservation and emission reduction goals.

[0003] In addition, the application of carbon dioxide as a natural working fluid in heat pump systems has also attracted attention. CO2 heat pump technology uses CO2 as a refrigerant and can be divided into subcritical, transcritical, and supercritical cycles depending on the cycle conditions. Among them, the transcritical CO2 heat pump cycle has a significant characteristic: when releasing heat in the supercritical pressure region, the CO2 temperature can change smoothly over a wide range (e.g., from 120°C to 20°C). This temperature glide phenomenon allows it to achieve good matching with heat transfer media with different temperature requirements, thus flexibly adapting to various heating scenarios and broadening the application range of heat pumps.

[0004] Although the two types of technologies mentioned above are for carbon capture and thermal energy conversion respectively, the commonly used CO2 capture processes still generally face the problem of high energy consumption, especially the large thermal energy demand in the desorption process.

[0005] Therefore, how to combine heat pump technology with carbon capture processes to reduce desorption energy consumption and improve overall system energy efficiency is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a water-ring heat pump system for waste heat utilization in carbon capture systems, which can combine heat pump technology with the carbon capture process to reduce desorption energy consumption and improve the overall system energy efficiency.

[0007] To solve the above-mentioned technical problems, the present invention provides a water-ring heat pump system for waste heat utilization in carbon capture systems, including an absorption tower, a flash tank, a regeneration tower, a first heat pump, a second heat pump, a third heat pump, and a regeneration gas separator.

[0008] The first heat pump includes a rich liquid heater, the second heat pump includes a lean liquid cooler, and the third heat pump includes a regenerated gas cooler.

[0009] The inlet of the absorption tower is used to introduce raw material gas. The rich liquid outlet of the absorption tower is connected to the rich liquid inlet of the flash tank. The rich liquid outlet of the flash tank is connected to the refrigerant inlet of the rich liquid heater. The refrigerant outlet of the rich liquid heater is connected to the rich liquid inlet of the regeneration tower. The lean liquid outlet of the regeneration tower is connected to the heat medium inlet of the lean liquid cooler. The heat medium outlet of the lean liquid cooler is connected to the lean liquid inlet of the absorption tower.

[0010] The regeneration tower's regeneration gas outlet is connected to the regeneration gas cooler's heat medium inlet, the regeneration gas cooler's heat medium outlet is connected to the regeneration gas separator's gas inlet, the regeneration gas separator's gas outlet is used to discharge carbon dioxide gas, and the regeneration gas separator's condensate outlet is connected to the regeneration tower's condensate inlet.

[0011] Optionally, the water-ring heat pump system for waste heat utilization in the carbon capture system described above further includes a fourth heat pump and a steam heater. The fourth heat pump includes a regenerated liquid preheater, the refrigerant inlet of which is connected to the regenerated liquid outlet of the regeneration tower, the refrigerant outlet of which is connected to the refrigerant inlet of the steam heater, and the refrigerant outlet of the steam heater is connected to the regenerated liquid inlet of the regeneration tower.

[0012] Optionally, in the above-described water-ring heat pump system for utilizing waste heat from a carbon capture system, at least one of the first heat pump, the second heat pump, the third heat pump, and the fourth heat pump is a water-ring carbon dioxide heat pump.

[0013] Optionally, in the above-mentioned water-ring heat pump system for waste heat utilization of carbon capture system, the first heat pump further includes a first evaporator, the second heat pump further includes a first condenser, the third heat pump further includes a second condenser, and the fourth heat pump further includes a second evaporator.

[0014] The refrigerant inlet of the second condenser is used to introduce circulating water. The refrigerant outlet of the second condenser is connected to the heat medium inlet of the second evaporator. The heat medium outlet of the second evaporator is connected to the refrigerant inlet of the first condenser. The refrigerant outlet of the first condenser is connected to the heat medium inlet of the first evaporator. The heat medium outlet of the first evaporator is used to discharge circulating water.

[0015] The refrigerant outlet of the first evaporator is connected to the heat medium inlet of the rich liquid heater, and the heat medium outlet of the rich liquid heater is connected to the refrigerant inlet of the first evaporator. The heat medium outlet of the first condenser is connected to the refrigerant inlet of the lean liquid cooler, and the refrigerant outlet of the lean liquid cooler is connected to the heat medium inlet of the first condenser. The heat medium outlet of the second condenser is connected to the refrigerant inlet of the regenerated gas cooler, and the refrigerant outlet of the regenerated gas cooler is connected to the heat medium inlet of the second condenser. The refrigerant outlet of the second evaporator is connected to the heat medium inlet of the regenerated liquid preheater, and the heat medium outlet of the regenerated liquid preheater is connected to the refrigerant inlet of the second evaporator.

[0016] Optionally, the water-loop heat pump system for waste heat utilization in the carbon capture system described above also includes an auxiliary heat source converter and an auxiliary cold source. The heat medium inlet of the auxiliary heat source converter is provided with a water supply pipe, the heat medium outlet of the auxiliary heat source converter is connected to the cold medium inlet of the second condenser, and the two ends of the cold medium channel of the auxiliary heat source converter are connected to the two ends of the auxiliary cold source.

[0017] Optionally, in the above-mentioned water-ring heat pump system for waste heat utilization of carbon capture system, the heat medium outlet of the first evaporator is connected to the water supply pipe;

[0018] And / or, a circulation pump is connected in series on the water supply pipe.

[0019] Optionally, in the above-mentioned water-ring heat pump system for waste heat utilization of carbon capture system, the refrigerant inlet and refrigerant outlet of the auxiliary cold source converter are connected to the auxiliary cold source through the auxiliary cold source inlet pipe and the return pipe, respectively, and a second valve and a first valve are connected in series on the auxiliary cold source inlet pipe and the return pipe, respectively.

[0020] The heat medium inlet and outlet of the auxiliary heat source converter are connected to the auxiliary heat medium inlet and auxiliary heat medium outlet through the auxiliary heat source inlet pipe and the return water pipe, respectively. A fourth valve and a third valve are connected in series on the auxiliary heat source inlet pipe and the return water pipe, respectively.

[0021] Optionally, in the above-mentioned water-loop heat pump system for waste heat utilization of carbon capture system, the auxiliary cold source is water-cooled or air-cooled.

[0022] And / or, the auxiliary heat source of the auxiliary heat medium inlet is hot water or steam.

[0023] Optionally, in the above-mentioned water-ring heat pump system for waste heat utilization of carbon capture system, a lean liquid pump is connected in series between the heat medium outlet of the lean liquid cooler and the lean liquid inlet of the absorption tower.

[0024] Optionally, in the water-ring heat pump system for waste heat utilization of the carbon capture system described above, the flash vapor discharged from the gas outlet of the flash tank is used to send upstream process gas.

[0025] And / or, the carbon dioxide gas discharged from the gas outlet of the regenerated gas separator is used to send to downstream subsequent processes;

[0026] And / or, the raw material gas is one of vertical furnace reducing gas, blast furnace gas, or power plant flue gas.

[0027] This invention provides a water-loop heat pump system for waste heat utilization in carbon capture systems, which has the following advantages:

[0028] This system integrates a multi-stage heat pump design, allowing the medium-to-high temperature waste heat recovered by the second and third heat pumps to serve as the driving heat source for the first heat pump or directly for preheating the rich liquid and the regenerated liquid at the bottom of the regeneration tower, forming a closed loop of internal energy cascade utilization. Simultaneously, by combining heat pump technology with the carbon capture process, adopting a model of "waste heat driving heat pumps, heat pumps improving the waste heat grade before reusing it in the process," the system efficiently recovers and upgrades the low-temperature waste heat generated in the carbon capture process, significantly reducing steam consumption in the regeneration stage, i.e., desorption energy consumption, thereby greatly improving the energy efficiency and economy of the entire carbon capture system. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 A process flow diagram of a water-ring heat pump system for waste heat utilization in a carbon capture system is provided in an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the absorption tower provided in an embodiment of the present invention.

[0032] In the image above:

[0033] 100-Absorber; 200-Flash Tank; 300-Regeneration Tower; 410-First Heat Pump; 411-Rich Liquid Heater; 412-First Evaporator; 420-Second Heat Pump; 421-Lean Liquid Cooler; 422-First Condenser; 423-Lean Liquid Pump; 430-Third Heat Pump; 431-Regeneration Gas Cooler; 432-Second Condenser; 440-Fourth Heat Pump; 441-Regeneration Liquid Preheater; 442-Second Evaporator; 500-Regeneration Gas Separator; 600-Steam Heater; 700-Auxiliary Cold and Heat Source Heat Exchanger; 710-Circulation Pump; 800-Auxiliary Cold Source;

[0034] V1 - First valve; V2 - Second valve; V3 - Third valve; V4 - Fourth valve;

[0035] P1 - First pipe; P2 - Second pipe; P3 - Third pipe; P4 - Fourth pipe; P5 - Fifth pipe; P6 - Sixth pipe; P7 - Seventh pipe; P8 - Eighth pipe; P9 - Ninth pipe; P10 - Tenth pipe; P11 - Eleventh pipe; P12 - Twelfth pipe. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] The core of this invention is to provide a water-ring heat pump system for waste heat utilization in carbon capture systems, which can combine heat pump technology with the carbon capture process to reduce desorption energy consumption and improve the overall system energy efficiency.

[0038] To enable those skilled in the art to better understand the technical solutions provided by the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] For details, please refer to Figure 1 and Figure 2 The present invention provides a water-ring heat pump system for waste heat utilization in a carbon capture system, comprising: an absorption tower 100, a flash tank 200, a regeneration tower 300, a first heat pump 410, a second heat pump 420, a third heat pump 430, and a regeneration gas separator 500.

[0040] The first heat pump 410 includes a rich liquid heater 411, whose core function is to preheat the rich liquid to be regenerated using a low-grade heat source. The second heat pump 420 includes a lean liquid cooler 421, whose core function is to cool the high-temperature lean liquid flowing out from the bottom of the regeneration tower 300 and recover its sensible heat. The third heat pump 430 includes a regeneration gas cooler 431, whose core function is to condense the high-temperature regeneration gas (mainly a mixture of CO2 and some water vapor) discharged from the top of the regeneration tower 300 and recover its latent heat and sensible heat.

[0041] The system consists of two main parts: a carbon capture process and a heat pump process.

[0042] The carbon capture process is as follows: Raw gas (such as flue gas containing carbon dioxide) from the boundary area, after dust removal and cooling, enters the inlet at the bottom of the absorption tower 100 and comes into countercurrent contact with the low-temperature lean liquid sprayed from the top of the absorption tower 100. The lean liquid absorbs carbon dioxide from the reducing gas and becomes rich liquid, flowing out from the rich liquid outlet at the bottom of the absorption tower 100. It then enters the flash tank 200 via the first pipe P1 for flash evaporation, where some dissolved acidic gases and a small amount of water vapor are flashed out at a lower pressure to reduce the heat load on the subsequent regeneration tower 300. Subsequently, the rich liquid enters the rich liquid heater 411 via the second pipe P2. Here, the rich liquid acts as the refrigerant (i.e., the object being heated) on the refrigerant side of the first heat pump 410, absorbing the cold energy released during refrigerant evaporation (i.e., the actual heat gained), resulting in an initial temperature increase. The preheated rich liquid flows out from the refrigerant outlet of the rich liquid heater 411 and enters the rich liquid inlet at the upper part of the regeneration tower 300 via the third pipe P3 for desorption and regeneration. Inside the regeneration tower 300, as the rich liquid flows downwards, it is further heated by heat supplied from the bottom of the tower (using low-pressure steam or other heat sources), resulting in a desorption reaction that releases a high concentration of carbon dioxide gas. The regenerated high-temperature lean liquid, obtained after the desorption reaction, is discharged from the lean liquid outlet at the bottom of the regeneration tower 300. After desorption of carbon dioxide within the regeneration tower, the rich liquid becomes lean liquid, which then enters the lean liquid cooler 421 of the second heat pump 420 via the fourth pipe P4 for cooling. In the lean liquid cooler 421, the lean liquid acts as the heat medium (i.e., the object being cooled) on the refrigerant side of the second heat pump 420, transferring its sensible heat to the refrigerant and significantly reducing its own temperature to a suitable level for returning to the absorption tower 100 to absorb carbon dioxide. The cooled lean liquid flows out from the heat medium outlet of the lean liquid cooler 421 and returns to the lean liquid inlet at the top of the absorption tower 100 via the sixth pipe P6, re-participating in the absorption process and forming a complete absorption-regeneration cycle.

[0043] After desorption within the regeneration tower 300, the rich liquid becomes high-temperature regeneration gas, which is discharged from the regeneration gas outlet at the top of the regeneration tower 300 and flows into the regeneration gas cooler 431 of the third heat pump 430 via the seventh pipe P7. In the regeneration gas cooler 431, the regeneration gas acts as the heat medium on the refrigerant side of the third heat pump 430 and is cooled by the refrigerant. This process not only condenses most of the water vapor in the regeneration gas, releasing a large amount of latent heat of vaporization which is recovered by the third heat pump 430, but also reduces the sensible heat of the regeneration gas itself. The cooled regeneration gas flows out from the heat medium outlet of the regeneration gas cooler 431 and enters the regeneration gas separator 500 via the eighth pipe P8 for gas-liquid separation. The separated carbon dioxide gas is discharged from the gas outlet at the top of the regeneration gas separator 500 for subsequent compression, utilization, or storage (e.g., sent to downstream processes). The condensate flows out from the condensate outlet at the bottom of the regeneration gas separator 500 and flows back to the top of the regeneration tower 300 via the ninth pipe P9 to maintain system balance.

[0044] This invention provides a water-loop heat pump system for waste heat utilization in carbon capture systems. This system integrates a multi-stage heat pump design, allowing the medium-to-high temperature waste heat recovered by the second heat pump 420 and the third heat pump 430 to serve as the driving heat source for the first heat pump 410 or directly for preheating the rich liquid and the regenerated liquid at the bottom of the regeneration tower, forming a closed loop of internal energy cascade utilization. Simultaneously, by combining heat pump technology with the carbon capture process, adopting a mode of "waste heat driving the heat pump, and the heat pump improving the waste heat grade before reusing it in the process," it efficiently recovers and upgrades the low-temperature waste heat generated in the carbon capture process, significantly reducing steam consumption in the regeneration stage, i.e., desorption energy consumption, thereby greatly improving the energy efficiency and economy of the entire carbon capture system.

[0045] To further recover energy, in this specific embodiment, the solution also includes a fourth heat pump 440 and a steam heater 600. The fourth heat pump 440 includes a regenerated liquid preheater 441. The refrigerant inlet of the regenerated liquid preheater 441 is connected to the regenerated liquid outlet in the middle of the regeneration tower 300, extracting a portion of the medium-temperature regenerated liquid (temperature between the rich liquid inlet and the lean liquid outlet) from the regeneration tower 300. The refrigerant outlet of the regenerated liquid preheater 441 is connected to the refrigerant inlet of the steam heater 600. The refrigerant outlet of the steam heater 600 is connected to the regenerated liquid inlet at the bottom of the regeneration tower 300. The heat medium inlet of the steam heater 600 is used to introduce external steam, and its heat medium outlet is used to discharge condensate. The generated condensate can be returned to the power plant's thermal system or used for subsequent processes.

[0046] The desorption of carbon dioxide from the rich liquid in the regeneration tower requires heat. In this invention, a stream of regenerated liquid is drawn from the bottom of the regeneration tower 300. It first enters the regenerated liquid preheater 441 of the fourth heat pump 440 via the tenth pipe P10, where it is initially heated. Then, it enters the steam heater 600 via the eleventh pipe P11, where external steam further raises the temperature of the regenerated liquid. Once the required temperature is reached, it returns to the lower part of the regeneration tower 300 via the twelfth pipe P12 for recycling. The fourth heat pump 440 also absorbs heat from a low-temperature heat source within the system to preheat the regenerated liquid, thereby reducing the steam consumption of the steam heater 600. The condensate discharged from the steam heater 600 still contains considerable heat and can be returned to the power plant's thermal system for further utilization.

[0047] In one specific embodiment of the present invention, at least one of the first heat pump 410, the second heat pump 420, the third heat pump 430, and the fourth heat pump 440 is a water-ring carbon dioxide heat pump. Water-ring carbon dioxide heat pumps use CO2 as the refrigerant, have a wide evaporation temperature range, high energy efficiency, and are particularly suitable for absorbing heat from low-temperature heat sources. The medium in the carbon dioxide heat pump can be liquid carbon dioxide or supercritical carbon dioxide. In this system, the low-temperature heat source for the second heat pump 420 and the third heat pump 430 can be factory circulating cooling water or ambient air. The increased heat can be supplied to the evaporator side of the first heat pump 410, forming a heat pump coupling, or directly used to heat the rich liquid, preheat the regenerated liquid, or provide domestic hot water, etc. Using CO2 as the working fluid also reflects the concept of environmental protection.

[0048] In the scenario used in this invention, the temperatures of the rich liquid flowing out of the absorption tower 100, the lean liquid flowing out of the regeneration tower 300, the regenerated liquid, and the regenerated gas are all within the operating range of the water-ring carbon dioxide heat pump. Applying the water-ring carbon dioxide heat pump to the carbon capture system optimizes the process flow and provides energy-saving and carbon-reducing benefits.

[0049] In a specific embodiment, the first heat pump 410 further includes a first evaporator 412, the second heat pump 420 further includes a first condenser 422, the third heat pump 430 further includes a second condenser 432, and the fourth heat pump 440 further includes a second evaporator 442.

[0050] The refrigerant inlet of the second condenser 432 is used to introduce circulating water. The refrigerant outlet of the second condenser 432 is connected to the heat transfer inlet of the second evaporator 442. The heat transfer outlet of the second evaporator 442 is connected to the refrigerant inlet of the first condenser 422. The refrigerant outlet of the first condenser 422 is connected to the heat transfer inlet of the first evaporator 412. The heat transfer outlet of the first evaporator 412 is used to discharge circulating water. Circulating water or other antifreeze media such as ethylene glycol can be used to connect and balance the heating and cooling of the system.

[0051] The refrigerant outlet of the first evaporator 412 is connected to the heat medium inlet of the rich liquid heater 411, and the heat medium outlet of the rich liquid heater 411 is connected to the refrigerant inlet of the first evaporator 412. The heat medium outlet of the first condenser 422 is connected to the refrigerant inlet of the lean liquid cooler 421, and the refrigerant outlet of the lean liquid cooler 421 is connected to the heat medium inlet of the first condenser 422. The heat medium outlet of the second condenser 432 is connected to the refrigerant inlet of the regenerated gas cooler 431, and the refrigerant outlet of the regenerated gas cooler 431 is connected to the heat medium inlet of the second condenser 432. The refrigerant outlet of the second evaporator 442 is connected to the heat medium inlet of the regenerated liquid preheater 441, and the heat medium outlet of the regenerated liquid preheater 441 is connected to the refrigerant inlet of the second evaporator 442.

[0052] The process flow of a water-ring carbon dioxide heat pump is as follows:

[0053] After absorbing heat in the third heat pump 430, the circulating water enters the fourth heat pump 440 through pipe X3 to release heat. After releasing heat, the circulating water enters the second heat pump 420 through pipe X4 to absorb heat. After absorbing heat, the circulating water enters the first heat pump 410 through pipe X5 to release heat. After releasing heat, the circulating water is discharged.

[0054] In the first heat pump 410, the first evaporator 412 of the first heat pump 410 absorbs heat from the circulating water and flows the heat into the rich liquid heater 411 through the pipe G1. The carbon dioxide refrigerant after heat exchange in the rich liquid heater 411 returns to the first heat pump 410 for recycling through the pipe H1.

[0055] In the second heat pump 420, carbon dioxide refrigerant absorbs heat in the lean liquid cooler 421 and returns the heat to the first condenser 422 of the second heat pump 420 through pipe H2. After the circulating water passes through the first condenser 422, it carries away the heat. The cooled carbon dioxide is then transported to the lean liquid cooler 421 through pipe G2 to absorb heat and is recycled.

[0056] In the fourth heat pump 440, the second evaporator 442 absorbs heat from the circulating water and flows the heat into the regenerated liquid preheater 441 through pipe G3. The carbon dioxide refrigerant that has exchanged heat in the regenerated liquid preheater 441 returns to the fourth heat pump 440 for recycling via H3.

[0057] Inside the third heat pump 430, the carbon dioxide refrigerant absorbs heat in the regenerated gas cooler 431 and returns the heat to the second condenser 432 of the third heat pump 430 through pipe H4. The circulating water carries away the heat after passing through the second condenser 432, and the cooled carbon dioxide is then transported to the regenerated gas condenser through pipe G4 to absorb heat and be used in internal circulation.

[0058] The first heat pump 410 uses a rich liquid heater 411 to transfer the low-grade heat to a higher temperature for preheating the rich liquid before it enters the regeneration tower, directly reducing the consumption of external high-grade heat energy required by the reboiler at the bottom of the regeneration tower. The second heat pump 420 uses the sensible heat of the high-temperature lean liquid as its heat source. The lean liquid cooler 421, acting as the evaporator of the second heat pump 420, cools the lean liquid while simultaneously increasing the grade of the recovered heat, which is then released through the cooler end of the second heat pump 420. This heat source serves as part of the driving heat source for the first heat pump 410 or the fourth heat pump 440, or is used for external purposes such as preheating boiler feedwater. The third heat pump 430 uses the latent and sensible heat released during the condensation of the high-temperature regeneration gas. The regeneration gas cooler 431, acting as the evaporator of the third heat pump 430, recovers this heat and increases its grade.

[0059] The core feature of this invention is that it utilizes a circulation system to meet the heating and cooling requirements of various parts through a loop pipe, based on the heating and cooling requirements during the carbon capture process.

[0060] Considering the potential for uneven heating and cooling in the system, this solution also includes an auxiliary heat source converter 700 and an auxiliary cold source 800. The auxiliary heat source converter 700 has a water supply pipe at its circulating water inlet, and its circulating water outlet is connected to the refrigerant inlet of the second condenser 432. Both ends of the refrigerant passage in the auxiliary heat source converter 700 are connected to both ends of the auxiliary cold source 800. Both ends of the heat source passage in the auxiliary heat source converter 700 are connected to the auxiliary heat source.

[0061] Specifically, the heat transfer medium outlet of the first evaporator 412 is connected to the water supply pipe. A circulation pump 710 is connected in series on the water supply pipe, such as... Figure 1 A portion of the circulating water enters pipe X7 through the water inlet, while another portion of the circulating water from the first evaporator 412 enters pipe X7 from pipe X6. Pipe X7 is then connected to the circulating pump 710 and enters the circulating water channel of the auxiliary heat source converter 700 through pipe X1 to enhance the circulation power.

[0062] When there is excess heat, the auxiliary heat source converter 700 can switch to cold source mode. Its refrigerant passage is connected to the auxiliary cold source 800, which dissipates excess heat in the system into the environment, thereby ensuring that the heat pump operates stably under optimal conditions.

[0063] When heat is insufficient, the auxiliary heat source converter 700 can switch to heat source mode. External heat medium is introduced through its heat medium inlet water pipe as a supplementary heat source for the water circulation system, thereby ensuring sufficient heat within the system and maintaining stable operation of the circulation system.

[0064] Furthermore, the refrigerant inlet and refrigerant outlet of the auxiliary cold and heat source converter 700 are connected to the auxiliary cold source 800 through the auxiliary cold source inlet water pipe and the return water pipe, respectively. The auxiliary cold source inlet water pipe and the return water pipe are respectively connected in series with a second valve V2 and a first valve V1.

[0065] The auxiliary heat source converter 700 has a heat medium inlet and a heat medium outlet connected to the auxiliary heat medium inlet and the auxiliary heat medium outlet respectively through an auxiliary heat source inlet pipe and a return water pipe. A fourth valve V4 and a third valve V3 are connected in series on the auxiliary heat source inlet pipe and the return water pipe respectively.

[0066] When the system's cooling capacity is insufficient, valves V1 and V2 are opened, while valves V3 and V4 are closed. Cooling capacity is then supplied to the circulating water pipes via an auxiliary cooling source 800, which can be water-cooled or air-cooled. When the system's heating capacity is insufficient, valves V1 and V2 are closed, while valves V3 and V4 are opened. Heat is then supplied to the circulating water pipes via an auxiliary heat source, which can be hot water or steam.

[0067] To improve the power of lean liquid circulation, a lean liquid pump 423 is connected in series between the heat medium outlet of the lean liquid cooler 421 and the lean liquid inlet of the absorption tower 100.

[0068] In a specific embodiment, the flash vapor discharged from the gas outlet of the flash tank 200 is used to send upstream process gas. After the rich liquid enters the flash tank 200, it is split into two paths: one is flash vapor, which is sent upstream via the top of the flash tank 200 for use as process gas; the other is rich liquid, which enters the rich liquid heater 411 via the second pipeline P2.

[0069] The carbon dioxide gas discharged from the gas outlet of the regenerated gas separator 500 is used to send to downstream subsequent processes. The feed gas is one of the following: vertical shaft furnace reducing gas, blast furnace gas, or power plant flue gas.

[0070] In summary, this invention provides a water-ring heat pump system for waste heat utilization in carbon capture systems. This system enables deep utilization of waste heat throughout the entire process of carbon capture systems, including vertical shaft furnace reducing gas, blast furnace gas, and power plant flue gas. It significantly reduces energy waste during carbon dioxide capture. Utilizing carbon dioxide heat pump technology, it further increases the temperature of the rich liquid entering the regeneration tower at 300°C and decreases the temperature of the lean liquid entering the absorption tower at 100°C. Furthermore, while lowering the temperature of the regeneration gas downstream of desorption, it preheats the regeneration liquid. Compared to traditional rich-lean-lean liquid heat exchangers, this system effectively reduces equipment size and further increases the temperature of the rich liquid entering the regeneration tower at 300°C and decreases the temperature of the lean liquid entering the absorption tower at 100°C.

[0071] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0072] In the description of this application, "multiple" means two or more. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0073] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0075] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A water-loop heat pump system for waste heat utilization in a carbon capture system, characterized in that, It includes an absorption tower (100), a flash tank (200), a regeneration tower (300), a first heat pump (410), a second heat pump (420), a third heat pump (430), and a regeneration gas separator (500). The first heat pump (410) includes a rich liquid heater (411), the second heat pump (420) includes a lean liquid cooler (421), and the third heat pump (430) includes a regenerated gas cooler (431). The inlet of the absorption tower (100) is used to introduce raw material gas. The rich liquid outlet of the absorption tower (100) is connected to the rich liquid inlet of the flash tank (200). The rich liquid outlet of the flash tank (200) is connected to the refrigerant inlet of the rich liquid heater (411). The refrigerant outlet of the rich liquid heater (411) is connected to the rich liquid inlet of the regeneration tower (300). The lean liquid outlet of the regeneration tower (300) is connected to the heat medium inlet of the lean liquid cooler (421). The heat medium outlet of the lean liquid cooler (421) is connected to the lean liquid inlet of the absorption tower (100). The regeneration gas outlet of the regeneration tower (300) is connected to the heat medium inlet of the regeneration gas cooler (431), the heat medium outlet of the regeneration gas cooler (431) is connected to the gas inlet of the regeneration gas separator (500), the gas outlet of the regeneration gas separator (500) is used to discharge carbon dioxide gas, and the condensate outlet of the regeneration gas separator (500) is connected to the condensate inlet of the regeneration tower (300).

2. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 1, characterized in that, It also includes a fourth heat pump (440) and a steam heater (600). The fourth heat pump (440) includes a regenerated liquid preheater (441). The refrigerant inlet of the regenerated liquid preheater (441) is connected to the regenerated liquid outlet of the regeneration tower (300). The refrigerant outlet of the regenerated liquid preheater (441) is connected to the refrigerant inlet of the steam heater (600). The refrigerant outlet of the steam heater (600) is connected to the regenerated liquid inlet of the regeneration tower (300).

3. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 2, characterized in that, At least one of the first heat pump (410), the second heat pump (420), the third heat pump (430) and the fourth heat pump (440) is a water ring carbon dioxide heat pump.

4. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 3, characterized in that, The first heat pump (410) further includes a first evaporator (412), the second heat pump (420) further includes a first condenser (422), the third heat pump (430) further includes a second condenser (432), and the fourth heat pump (440) further includes a second evaporator (442). The refrigerant inlet of the second condenser (432) is used to introduce circulating water. The refrigerant outlet of the second condenser (432) is connected to the heat medium inlet of the second evaporator (442). The heat medium outlet of the second evaporator (442) is connected to the refrigerant inlet of the first condenser (422). The refrigerant outlet of the first condenser (422) is connected to the heat medium inlet of the first evaporator (412). The heat medium outlet of the first evaporator (412) is used to discharge circulating water. The refrigerant outlet of the first evaporator (412) is connected to the heat medium inlet of the rich liquid heater (411), and the heat medium outlet of the rich liquid heater (411) is connected to the refrigerant inlet of the first evaporator (412). The heat medium outlet of the first condenser (422) is connected to the refrigerant inlet of the lean liquid cooler (421), and the refrigerant outlet of the lean liquid cooler (421) is connected to the heat medium inlet of the first condenser (422). The heat medium outlet of the second condenser (432) is connected to the refrigerant inlet of the regenerated gas cooler (431), and the refrigerant outlet of the regenerated gas cooler (431) is connected to the heat medium inlet of the second condenser (432). The refrigerant outlet of the second evaporator (442) is connected to the heat medium inlet of the regenerated liquid preheater (441), and the heat medium outlet of the regenerated liquid preheater (441) is connected to the refrigerant inlet of the second evaporator (442).

5. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 4, characterized in that, It also includes an auxiliary heat source converter (700) and an auxiliary cold source (800). The heat medium inlet of the auxiliary heat source converter (700) is provided with a water supply pipe. The heat medium outlet of the auxiliary heat source converter (700) is connected to the cold medium inlet of the second condenser (432). The two ends of the cold medium channel of the auxiliary heat source converter (700) are connected to the two ends of the auxiliary cold source (800).

6. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 5, characterized in that, The heat medium outlet of the first evaporator (412) is connected to the water supply pipe; And / or, a circulation pump (710) is connected in series on the water supply pipe.

7. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 5, characterized in that, The refrigerant inlet and refrigerant outlet of the auxiliary cold and heat source converter (700) are connected to the auxiliary cold source (800) through the auxiliary cold source inlet pipe and the return pipe, respectively. The auxiliary cold source inlet pipe and the return pipe are connected in series with a second valve (V2) and a first valve (V1). The heat medium inlet and outlet of the auxiliary heat source converter (700) are connected to the auxiliary heat medium inlet and auxiliary heat medium outlet through the auxiliary heat source inlet pipe and the return water pipe, respectively. A fourth valve (V4) and a third valve (V3) are connected in series on the auxiliary heat source inlet pipe and the return water pipe, respectively.

8. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 7, characterized in that, The auxiliary cooling source (800) is water-cooled or air-cooled; And / or, the auxiliary heat source of the auxiliary heat medium inlet is hot water or steam.

9. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 1, characterized in that, A lean liquid pump (423) is connected in series between the heat medium outlet of the lean liquid cooler (421) and the lean liquid inlet of the absorption tower (100).

10. The water-ring heat pump system for waste heat utilization in a carbon capture system according to claim 1, characterized in that, The flash vapor discharged from the gas outlet of the flash tank (200) is used to send the gas to the upstream process. And / or, the carbon dioxide gas discharged from the gas outlet of the regenerated gas separator (500) is used to send to downstream subsequent processes; And / or, the raw material gas is one of vertical furnace reducing gas, blast furnace gas, or power plant flue gas.

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