Tail gas carbon capture comprehensive treatment and cold energy recycling system

Abstract

The application discloses a tail gas carbon capture comprehensive treatment and cold energy recycling system, which comprises a tail gas carbon capture unit and a cold energy recycling unit. The tail gas carbon capture unit comprises a pretreatment device, a security device, a first regulating valve, a compressor, a second regulating valve, a gas storage tank, a third regulating valve, a CO2 separation device, a CO2 gas storage tank and a two-stage differential pressure turbine expander. The cold energy recycling unit comprises the two-stage differential pressure turbine expander, a fourth regulating valve, a desublimation chamber, a fifth regulating valve and a rich cold energy storage chamber. The pressure energy of the tail gas after carbon capture is innovatively utilized, is transported to the two-stage differential pressure turbine expander to expand and work, and the cold energy of the low-temperature exhaust gas after expansion is recycled. The high-efficiency carbon capture technology and the cold energy recycling technology are integrated, efficient tail gas carbon capture and cold energy recycling are realized, energy waste is minimized, and an economic and environment-friendly solution is provided for the industrial and energy fields.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tail gas carbon capture, and particularly relates to a tail gas carbon capture comprehensive treatment and cold energy recycling system. BACKGROUND

[0002] With the acceleration of global industrialization and social development, the tail gas emission generated in the industrial production process has become one of the main problems of environmental pollution and energy waste. Among them, carbon dioxide (CO2) is the main greenhouse gas, which has an important influence on global climate change. At present, some tail gas carbon capture systems and cold energy recycling technologies have been applied in the industrial field. However, due to the limitations of technology, there are still many problems to be solved, such as high system operation cost, difficulty in storing CO2 after capture, and ineffective utilization of cold energy. Therefore, a comprehensive treatment system is needed to improve the efficiency of tail gas carbon capture, and to obtain power to compensate for the economic cost of the system in the process, and further realize the recycling and reuse of cold energy.

[0003] Based on this, the patent proposes a tail gas carbon capture comprehensive treatment and cold energy recycling system, which adopts advanced separation technology to realize efficient capture of CO2 in tail gas. Through the selective process of the separation module, a high carbon capture efficiency is achieved; the system utilizes the pressure energy of the captured waste gas to transport it to a two-stage differential pressure turbine expander to do work, and the waste gas obtains low temperature, which can recycle the cold energy to condense CO2 into dry ice, facilitating high-density storage and safe transportation of carbon resources, and expanding the application scenarios of CO2.

[0004] The tail gas carbon capture comprehensive treatment and cold energy recycling system integrating the above technologies can realize efficient tail gas carbon capture and cold energy recycling and reuse, and can minimize energy waste, providing an economic and environmentally friendly solution for the industrial and energy fields, and achieving energy saving and emission reduction. SUMMARY

[0005] The application aims to provide a tail gas carbon capture comprehensive treatment and cold energy recycling system, which optimizes the design of the tail gas CO2 capture process, and innovatively transports the waste gas after carbon capture to a two-stage differential pressure expander to do work, and uses the low-temperature waste gas after work to cool CO2 into dry ice, realizing efficient capture, high-density storage and safe transportation of CO2, expanding the application scenarios of CO2, reducing the risk of gas leakage, recycling energy and reusing it, and achieving energy saving and emission reduction, to solve the problems raised in the above background technology.

[0006] In order to achieve the above object, the present application provides the following technical scheme: a tail gas carbon capture comprehensive treatment and cold energy recycling system, comprising a tail gas carbon capture unit and a cold energy recycling unit, wherein the tail gas carbon capture unit comprises a pretreatment device, a safety device, a first regulating valve, a compressor, a second regulating valve, a gas storage tank, a third regulating valve, a CO2 separation device, a CO2 storage tank and a two-stage differential pressure turbine expander; the outlet of the pretreatment device is connected to the safety device through a heat insulation pipeline, the safety device is internally provided with explosion-proof ports, a gas detector, a filter and other sub-components, the compressor is connected to the safety device through a heat insulation pipeline and the first regulating valve, the gas storage tank is fixed to the rear of the compressor and connected to the compressor through a heat insulation pipeline and the second regulating valve; the CO2 separation device is connected to the gas storage tank through a heat insulation pipeline and the third regulating valve, and comprises a separation module, a feed inlet, a first discharge outlet and a second discharge outlet; the CO2 storage tank is connected to the first discharge outlet of the CO2 separation device through a heat insulation pipeline; the two-stage differential pressure turbine expander comprises a first-stage working section, a permanent magnet generator, a bearing, a second-stage working section and a gas-liquid separator; the inlet of the first-stage working section is connected to the second discharge outlet of the CO2 separation device through a heat insulation pipeline, the outlet of the first-stage working section is connected to the inlet of the second-stage working section through a pipeline, the two working sections are connected through the bearing, the permanent magnet generator is installed in the middle of the bearing, and the gas-liquid separator is fixedly embedded at the diffuser and the outlet pipeline of the first-stage working section; the cold energy recycling unit comprises the two-stage differential pressure turbine expander, a fourth regulating valve, a desublimation chamber, a fifth regulating valve and a rich cold energy storage chamber; the low-temperature conveying pipeline at the outlet of the second-stage working section is divided into two paths, the first path is sequentially connected to the fourth regulating valve and the desublimation chamber, and the second path is sequentially connected to the fifth regulating valve and the rich cold energy storage chamber; the desublimation chamber is provided with an inner layer structure, an outer layer structure and two inlets, the first inlet is connected to the fourth regulating valve and the outer layer of the desublimation chamber, and the second inlet is connected to the CO2 storage tank and the inner layer of the desublimation chamber.

[0007] Preferably, the liquid storage chamber of the gas-liquid separator is provided with a liquid outlet.

[0008] Preferably, the desublimation chamber is provided with a control system and an exhaust port.

[0009] Preferably, the CO2 storage tank is provided with an outlet.

[0010] Preferably, the rich cold energy storage chamber is provided with an output end.

[0011] Compared with the prior art, the present application has the following beneficial effects:

[0012] 1. The present invention discloses a tail gas carbon capture and integrated treatment and cold energy recovery and reuse system. It optimizes the tail gas CO2 capture process and innovatively utilizes the pressure energy of the tail gas after carbon capture to transport it to a two-stage differential pressure turbine expander for expansion and work, and recovers and reuses the cold energy of the expanded low-temperature exhaust gas. The present invention integrates high-efficiency carbon capture technology and cold energy recovery technology to achieve high-efficiency tail gas carbon capture and cold energy recovery and reuse, which can minimize energy waste and provide an economical and environmentally friendly solution for the industrial and energy sectors, achieving energy conservation and emission reduction. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the system of the present invention;

[0014] Figure 2 This is a schematic diagram of the two-stage differential pressure turbine expander structure of the present invention;

[0015] Figure 3 This is a schematic diagram of the system workflow of the present invention.

[0016] In the diagram: 1. Pretreatment device; 2. Safety device; 3. First regulating valve; 4. Compressor; 5. Second regulating valve; 6. Gas storage tank; 7. Third regulating valve; 8. CO2 separation device; 9. CO2 storage tank; 10. Two-stage differential pressure turbine expander; 11. Fourth regulating valve; 12. Sublimation chamber; 13. Fifth regulating valve; 14. Surplus cold energy storage chamber; 1001. First stage working section; 1002. Permanent magnet generator; 1003. Bearing; 1004. Second stage working section; 1005. Gas-liquid separator. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figures 1-3 As shown, the present invention provides a tail gas carbon capture and integrated treatment and cold energy recovery and reuse system, including a tail gas carbon capture unit and a cold energy recovery and reuse unit. The tail gas carbon capture unit includes a pretreatment device 1, a safety device 2, a first regulating valve 3, a compressor 4, a second regulating valve 5, a gas storage tank 6, a third regulating valve 7, a CO2 separation device 8, a CO2 gas storage tank 9, and a two-stage differential pressure turbine expander 10.

[0019] The front treatment device 1 outlet is connected with the security device 2 through the heat insulation pipeline, the security device 2 is internally provided with explosion-proof port, gas detector, filter and other sub-components, which are used for further filtering tail gas impurities and monitoring CO2 concentration in the tail gas, according to the concentration change to carry out tail gas delivery and cooperate with the opening and closing of the explosion-proof port in extreme cases, to ensure the safe and stable operation of the process; the compressor 4 is connected with the security device 2 through the heat insulation pipeline and the first regulating valve 3, which converts the normal pressure tail gas into high pressure state, improves the carbon density, provides necessary high pressure for the CO2 separation device 8, and further improves the carbon capture efficiency; the gas storage tank 6 is fixed behind the compressor 4, and the two are connected through the heat insulation pipeline and the second regulating valve 5, the compressed tail gas enters the gas storage tank 6 for stable flow, which balances the pressure of the tail gas to be captured, reduces the compression heat, improves the gas stability and the like; the CO2 separation device 8 is connected with the gas storage tank 6 through the heat insulation pipeline and the third regulating valve 7, which includes a separation module, a feed inlet, a first discharge outlet and a second discharge outlet, the CO2 storage tank 9 is connected with the first discharge outlet of the CO2 separation device 8 through the heat insulation pipeline, the tail gas to be captured enters the separation module through the feed inlet first, captures CO2 and separates CO2 by relying on the difference of CO2 solubility, diffusion rate and other properties on both sides of the separation module, the separated CO2 is transported to the CO2 storage tank 9 through the first discharge outlet and the heat insulation pipeline, and temporarily stored, which reduces the CO2 pressure, improves the gas stability and the like, and the separated waste gas is discharged to the two-stage differential pressure turbine expander 10 through the second discharge outlet; wherein the CO2 permeation flux (J) calculation formula is: J=P×A×D, P refers to the pressure difference of the tail gas, which represents the pressure difference between the feed side and the discharge side; A is the effective area of the separation module, which represents the separation module surface area through which the gas passes; D is the diffusion coefficient of the gas, which represents the diffusion rate of the gas in the separation material; wherein the selectivity (a) calculation formula is X refers to the mole fraction of CO2, X other is the mole fraction of other gases;

[0020] The two-stage pressure differential turbine expander 10 comprises a first stage working section 1001, a permanent magnet generator 1002, a bearing 1003, a second stage working section 1004, and a gas-liquid separator 1005. The first stage working section 1001 is connected to the second outlet of the CO2 separation device 8 through a heat insulation pipeline. The outlet of the first stage working section 1001 is connected to the inlet of the second stage working section 1004 through a pipeline. The two working sections are connected through the bearing 1003. The permanent magnet generator 1002 is installed in the middle of the bearing 1003. The gas-liquid separator 1005 is fixedly embedded in the diffuser and outlet pipeline of the first stage working section 1001. When the exhaust gas is expanded to about atmospheric pressure, its theoretical temperature is lower than the CO2 desublimation temperature. The two-stage pressure differential turbine expander 10 is used to prevent the very small amount of CO2 contained in the captured exhaust gas from being desublimated into solid dry ice when reaching the theoretical low temperature, thereby damaging the working wheel of the machine. The separated exhaust gas still contains a small amount of CO2. The exhaust gas first enters the first stage working section 1001 to expand to the critical pressure point of liquid CO2. The exhaust gas after the first stage working becomes a two-phase mixture of tail gas and a small amount of liquid CO2 in the diffuser of the first stage working section 1001. After separation by the gas-liquid separator 1005, the liquid is stored in the liquid storage chamber of the gas-liquid separator 1005. The exhaust gas flows through the gas-liquid separator 1005 and the pipeline to the second stage working section 1004 to expand to atmospheric pressure and become low-temperature exhaust gas. The exhaust gas during working conforms to the actual gas equation: pv=ZRT, where Z represents the gas compression factor. Let the total work obtained by the turbine expander be W t , the work done by the two-stage pressure differential turbine expander 10 be W t,1 , and the work done by the first stage pressure differential turbine expander be W t,2 . The total work calculation formula is: W t =W t,1 +W t,2 . The work calculation formula of each stage pressure differential turbine expander 10 is: n represents the change index of the thermal process of the first stage pressure differential turbine expander, which is determined by the manufacturing performance of the pressure differential turbine expander itself. R g represents the gas constant of the exhaust gas. T1 represents the inlet temperature of the first stage pressure differential turbine. T2 represents the outlet temperature of the first stage pressure differential turbine. T3 represents the inlet temperature of the second stage pressure differential turbine. T4 represents the outlet temperature of the second stage pressure differential turbine.

[0021] The cold energy recovery and reuse unit comprises the two-stage pressure differential turbine expander 10, a fourth regulating valve 11, a desublimation chamber 12, a fifth regulating valve 13, and a rich cold energy storage chamber 14.

[0022] The low-temperature conveying pipeline at the outlet of the second stage working section 1004 is divided into two routes. The first route is sequentially connected to the fourth regulating valve 11 and the desublimation chamber 12. The second route is sequentially connected to the fifth regulating valve 13 and the rich cold energy storage chamber 14, which is used to store the excess low-temperature exhaust gas used in the desublimation chamber 12.

[0023] The desublimation chamber 12 is provided with an inner and outer layer structure and two inlets, the first inlet is connected to the fourth regulating valve 11 and the outer layer of the desublimation chamber 12, and the second inlet is connected to the CO2 tank 9 and the inner layer of the desublimation chamber 12. The low-temperature waste gas entering the outer layer of the desublimation chamber 12 provides a low-temperature environment for the desublimation chamber 12, and the CO2 entering the inner layer of the desublimation chamber 12 sublimes into dry ice in the low-temperature environment and is stored therein.

[0024] As shown in Figure 2 , the liquid outlet is arranged in the liquid storage chamber of the gas-liquid separator 1005; in this embodiment, the liquid can be periodically discharged from the liquid storage chamber.

[0025] As shown in Figure 1 , the desublimation chamber 12 is equipped with a control system and an exhaust port; in this embodiment, the control system can identify the cold energy required for the sublimation process of the desublimation chamber 12 and cooperate with the fourth regulating valve 11 and the fifth regulating valve 13 to realize reasonable distribution of the low-temperature waste gas, and the exhaust port is used to discharge the high-temperature waste gas after providing cold energy; wherein the cold load calculation formula of the desublimation chamber 12 is Q1=m×ΔH, m represents the mass of CO2; ΔH represents the enthalpy change in the sublimation process, which is about 25.1 kJ / mol at normal temperature and pressure.

[0026] As shown in Figure 1 , the CO2 tank 9 is provided with an outlet; in this embodiment, the direct output of CO2 is realized.

[0027] As shown in Figure 1 , the excess cold energy storage chamber 14 is provided with an output end; in this embodiment, the excess cold energy storage chamber 14 is provided with an output end, and the low-temperature waste gas stored therein can be used for tail gas precooling or other cold energy utilization scenarios; ignoring the process loss, the cold energy load calculation formula of the excess cold energy storage chamber 14 is Q2=W t -Q1.

[0028] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for integrated treatment and cold energy recovery and reuse of exhaust gas carbon capture, comprising an exhaust gas carbon capture unit and a cold energy recovery and reuse unit, characterized in that, The exhaust carbon capture unit includes a pretreatment device (1), a safety device (2), a first regulating valve (3), a compressor (4), a second regulating valve (5), a gas storage tank (6), a third regulating valve (7), a CO2 separation device (8), a CO2 gas storage tank (9), and a two-stage differential pressure turbine expander (10). The outlet of the pretreatment device (1) is connected to the security device (2) via a heat-insulated pipe. The security device (2) is equipped with sub-components such as an explosion-proof port, a gas detector, and a filter. The compressor (4) is connected to the security device (2) via a heat-insulated pipe and the first regulating valve (3). The gas storage tank (6) is fixed to the compressor (4), and the two are connected via a heat-insulated pipe and the second regulating valve (5). The CO2 separation device (8) is connected to the gas storage tank (6) via a heat-insulated pipe and the third regulating valve (7). It includes a separation module, an inlet, a first outlet, and a second outlet. The CO2 storage tank (9) is connected to the first outlet of the CO2 separation device (8) via a heat-insulated pipe. The two-stage differential pressure turbine expander (10) includes a first-stage working section (1001), a permanent magnet generator (1002), a bearing (1003), a second-stage working section (1004), and a gas-liquid separator (1005). The inlet of the first-stage working section (1001) is connected to the second outlet of the CO2 separation device (8) through a heat-insulated pipe. The outlet of the first-stage working section (1001) is connected to the inlet of the second-stage working section (1004) through a pipe. The two working sections are connected through the bearing (1003). The permanent magnet generator (1002) is installed in the middle of the bearing (1003). The gas-liquid separator (1005) is fixedly embedded in the diffuser and outlet pipe of the first-stage working section (1001). The cold energy recovery and reuse unit includes the two-stage differential pressure turbine expander (10), the fourth regulating valve (11), the sublimation chamber (12), the fifth regulating valve (13), and the surplus cold energy storage chamber (14); The low-temperature conveying pipeline at the outlet of the second-stage working section (1004) is divided into two paths. The first path is connected in sequence to the fourth regulating valve (11) and the sublimation chamber (12), and the second path is connected in sequence to the fifth regulating valve (13) and the surplus cold energy storage chamber (14). The sublimation chamber (12) is provided with an inner and outer two-layer structure and two inlets. The first inlet is connected to the fourth regulating valve (11) and the outer layer of the sublimation chamber (12), respectively. The second inlet is connected to the CO2 storage tank (9) and the inner layer of the sublimation chamber (12), respectively.

2. The exhaust gas carbon capture and integrated treatment and cold energy recovery and reuse system according to claim 1, characterized in that, The gas-liquid separator (1005) has a liquid outlet in its storage chamber.

3. The exhaust gas carbon capture and integrated treatment and cold energy recovery and reuse system according to claim 1, characterized in that, The deposition chamber (12) is equipped with a control system and an exhaust port.

4. The exhaust gas carbon capture and integrated treatment and cold energy recovery and reuse system according to claim 1, characterized in that, The CO2 storage tank (9) is provided with an outlet.

5. The exhaust gas carbon capture and integrated treatment and cold energy recovery and reuse system according to claim 1, characterized in that, The surplus cold energy storage chamber (14) is equipped with an output terminal.

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