Carbon capture liquefaction and dry ice preparation system based on LNG (Liquefied Natural Gas) cold energy

Abstract

The utility model discloses a carbon capture liquefaction and dry ice preparation system based on LNG (Liquefied Natural Gas) cold energy, which comprises a carbon capture unit and a liquefaction and dry ice preparation unit, the carbon capture unit is configured to adsorb and desorb carbon dioxide, and the carbon dioxide desorbed by the carbon capture unit enters the liquefaction and dry ice preparation unit; wherein hot water of the photo-thermal unit serves as a heat source of the carbon capture unit, closed circulating cooling water of the gas-steam combined cycle unit serves as a cold source of the carbon capture unit, and cold energy generated in the LNG gasification process serves as cold energy of the liquefaction and dry ice preparation unit. A carbon capture liquefaction and dry ice preparation system based on LNG cold energy can achieve stepped utilization of energy, avoid waste of energy, improve the utilization rate of energy, prevent part of harmful energy and harmful gas from entering the atmosphere, improve the environmental protection performance of the system, produce gaseous, solid and liquid carbon dioxide, and improve the utilization rate of dry ice. And product diversification of the system is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of carbon dioxide treatment, in particular to a carbon capture liquefaction and dry ice preparation system based on LNG cold energy. Background Art

[0002] Against the backdrop of global warming, reducing atmospheric carbon dioxide concentrations has become an urgent task. As one of the main components of greenhouse gases, carbon dioxide emissions mainly come from the combustion of fossil fuels, especially in electricity production and industrial manufacturing processes. The development and application of carbon capture technology is one of the key ways to solve this problem. By effectively capturing and storing carbon dioxide, greenhouse gas emissions can be significantly reduced, the impact of climate change can be mitigated, and support can be provided for energy transformation and the development of a low-carbon economy.

[0003] Existing carbon capture technology injects captured carbon dioxide into underground oil layers for permanent storage. As time goes by, the area of ​​the oil layers that can store carbon dioxide will naturally decrease, making it inconvenient for the subsequent processing and utilization of more carbon dioxide, resulting in a waste of energy and causing air pollution. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art or related technology.

[0005] In view of this, the utility model provides a carbon capture liquefaction and dry ice preparation system based on LNG cold energy, which can realize the step-by-step utilization of energy, avoid energy waste, and improve energy utilization. At the same time, it can also prevent some harmful energy and harmful gases from entering the atmosphere, thereby improving the environmental performance of the system. On the other hand, it can produce gaseous, solid and liquid carbon dioxide to achieve product diversification.

[0006] Specifically, the following technical solutions are included:

[0007] The utility model provides a carbon capture liquefaction and dry ice preparation system based on LNG cold energy, comprising: a carbon capture unit and a liquefaction and dry ice preparation unit, wherein the carbon capture unit is configured to adsorb and desorb carbon dioxide, and the carbon dioxide desorbed by the carbon capture unit enters the liquefaction and dry ice preparation unit;

[0008] Among them, the hot water of the photothermal unit is used as the heat source of the carbon capture unit, the closed-loop cooling water of the gas-steam combined cycle unit is used as the cold source of the carbon capture unit, and the cold energy generated by the LNG gasification process is used as the cold energy of the liquefaction and dry ice preparation unit.

[0009] Optionally, the carbon capture unit comprises:

[0010] A first adsorption tower, wherein the first air inlet of the first adsorption tower is connected to the flue gas at the waste heat boiler outlet, the first liquid inlet and the first liquid outlet of the first adsorption tower are both connected to the photothermal unit, the first liquid inlet and the first liquid outlet are also both connected to the gas-steam combined cycle unit, and the first air outlet of the first adsorption tower is respectively connected to the liquefaction and dry ice preparation unit and the unit exhaust flue;

[0011] A second adsorption tower, wherein the second air inlet of the second adsorption tower is connected to the flue gas at the waste heat boiler outlet, the second liquid inlet and the second liquid outlet of the second adsorption tower are both connected to the photothermal unit, the second liquid inlet and the second liquid outlet are also both connected to the gas-steam combined cycle unit, and the second air outlet of the second adsorption tower is respectively connected to the liquefaction and dry ice preparation unit and the exhaust flue of the unit;

[0012] The communication refers to communication through a pipeline.

[0013] Optionally, a fifth flue gas damper is provided between the first air inlet and the flue gas at the waste heat boiler outlet, a sixth flue gas damper is provided between the second air inlet and the flue gas at the waste heat boiler outlet, a fourth flue gas damper is provided between the first air outlet and the unit exhaust duct, a second flue gas damper is provided between the second air outlet and the unit exhaust duct, a third flue gas damper is provided between the first air outlet and the liquefaction and dry ice preparation unit, and a first flue gas damper is provided between the second air outlet and the liquefaction and dry ice preparation unit;

[0014] Wherein, the smoke damper is configured to control the flow of gas.

[0015] Optionally, the gas-steam combined cycle unit comprises a cooling water intake and a cooling water return port, the cooling water intake is respectively connected to the first liquid inlet and the second liquid inlet, and the cooling water return port is respectively connected to the first liquid outlet and the second liquid outlet;

[0016] A first plate heat exchanger is provided at the cooling water intake and the cooling water return port, and a first booster pump is also provided on the pipeline of the cooling water intake.

[0017] Optionally, a sixth regulating valve is provided between the first booster pump and the first liquid inlet, a fifth regulating valve is provided between the first booster pump and the second liquid inlet, a third regulating valve is provided between the first liquid outlet and the first plate heat exchanger, and a fourth regulating valve is provided between the second liquid outlet and the first plate heat exchanger.

[0018] Optionally, the photothermal unit comprises a high-temperature water outlet and a high-temperature water return port, the high-temperature water outlet is respectively connected to the first liquid inlet and the second liquid inlet, and the high-temperature water return port is respectively connected to the first liquid outlet and the second liquid outlet;

[0019] A second plate heat exchanger is provided at the high-temperature water outlet and the high-temperature water return port, and a second booster pump is provided on the pipeline of the high-temperature water outlet.

[0020] Optionally, an eighth regulating valve is provided between the second booster pump and the first liquid inlet, a seventh regulating valve is provided between the second booster pump and the second liquid inlet, a second regulating valve is provided between the first liquid outlet and the second plate heat exchanger, and a first regulating valve is provided between the second liquid outlet and the second plate heat exchanger.

[0021] Optionally, the liquefaction and dry ice preparation unit comprises:

[0022] a first compressor, wherein a first inlet of the first compressor is used to receive carbon dioxide released by the carbon capture unit;

[0023] A first heat exchanger, wherein the inlet of the first heat exchanger is connected to the first outlet of the first compressor, and the outlet of the first heat exchanger is also connected to the combustion chamber of the gas turbine and the exhaust duct of the unit respectively;

[0024] a second heat exchanger, wherein the outlet of the second heat exchanger is connected to the inlet of the gas-liquid separator, the outlet of the gas-liquid separator is connected to the inlet of the first heat exchanger, and the outlet of the gas-liquid separator is also connected to the liquid storage tank;

[0025] a second compressor, wherein a second inlet of the second compressor is connected to an outlet of the first heat exchanger, and a second outlet of the second compressor is connected to an inlet of the second heat exchanger;

[0026] The inlet of the first heat exchanger and the inlet of the second heat exchanger are both connected to the LNG outlet, a first gas flow valve is provided between the LNG outlet and the first heat exchanger, and a second gas flow valve is provided between the LNG outlet and the second heat exchanger.

[0027] Optionally, the liquefaction and dry ice preparation unit further comprises:

[0028] A dry ice machine is connected to the outlet of the liquid storage tank, and a liquid carbon dioxide regulating valve is provided between the dry ice machine and the liquid storage tank;

[0029] A gas storage tank, wherein the inlet of the gas storage tank is connected to the gaseous carbon dioxide outlet of the dry ice machine, the outlet of the gas storage tank is connected to the first inlet of the first compressor, and a gaseous carbon dioxide regulating valve is provided between the gas storage tank and the first compressor.

[0030] Optionally, the liquefaction and dry ice preparation unit further comprises:

[0031] The inlet of the small steam turbine is connected to the outlet steam of the waste heat boiler, the first outlet of the small steam turbine is connected to the condenser, and the small steam turbine is connected to the crankshaft connecting rods of the first compressor and the second compressor respectively through a shaft chain, and the small steam turbine provides rotational kinetic energy for the first compressor and the second compressor.

[0032] The carbon capture liquefaction and dry ice preparation system based on LNG cold energy provided by the embodiment of the utility model comprises a carbon capture unit and a liquefaction and dry ice preparation unit. The carbon capture unit is used to capture carbon dioxide generated after combustion, adsorb and desorb carbon dioxide, and the desorbed carbon dioxide enters the liquefaction and dry ice preparation unit to provide raw materials for the preparation of dry ice, thereby avoiding direct emission of carbon dioxide into the atmosphere to cause pollution, and there is no need to seal the carbon dioxide in the underground oil layer to avoid occupying the oil layer area; at the same time, the hot water of the photothermal unit is used as the heat source of the carbon capture unit, and the closed-loop cooling water of the gas-steam combined cycle unit is used as the cold source of the carbon capture unit, so that the energy of the cold source and the heat source can be fully utilized to improve the energy utilization rate, and the cold energy generated by the LNG gasification process is used as the cold energy of the liquefaction and dry ice preparation unit, which, on the one hand, realizes the cascade utilization of energy and improves the energy utilization rate, and on the other hand, can also avoid the generation of cold energy pollution to a certain extent, thereby improving the environmental protection of the system.

[0033] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 It is a schematic diagram of a carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to an embodiment of the utility model.

[0036] in, Figure 1 The corresponding relationship between the reference numerals and the component names is as follows:

[0037] 1- small steam engine, 2.1 first compressor; 2.2 second compressor, 3.1 first heat exchanger, 3.2 second heat exchanger, 4.1 first flue gas damper, 4.2 second flue gas damper, 4.3 third flue gas damper, 4.4 fourth flue gas damper, 4.5 fifth flue gas damper, 4.6 sixth flue gas damper, 5.1 first adsorption tower, 5.2 second adsorption tower, 6.1 first gas flow valve, 6.2 second gas flow valve, 7 gas-liquid separator, 8 liquid storage tank, 10.1 first regulating valve, 10.2 second regulating valve, 10.3 third regulating valve, 10.4 fourth regulating valve, 10.5 fifth regulating valve, 10. 6 Sixth regulating valve, 10.7 Seventh regulating valve, 10.8 Eighth regulating valve, 11.1 First boosting pump, 11.2 Second boosting pump, 12.1 First plate heat exchanger, 12.2 Second plate heat exchanger, 14 Dry ice machine, 15- Gas storage tank, 16 Liquid carbon dioxide regulating valve, 17 Gaseous carbon dioxide regulating valve, 18.1 First heat exchanger regulating valve, 18.2 Second heat exchanger regulating valve, 18.3 Third heat exchanger regulating valve, 18.4 Fourth heat exchanger regulating valve, P1 Waste heat boiler outlet steam, P2 Condenser, P3 Waste heat boiler outlet flue gas, P4 Gas turbine combustion chamber, P5 Unit exhaust flue, P6 LNG outlet, P7 High temperature water outlet, P8- High temperature water return port, P9 Cooling water return port, P10 Cooling water intake port. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0039] Before further describing the embodiments of the present invention in detail, the directional terms involved in the embodiments of the present invention, such as "upper part", "lower part" and "side part", do not have the meaning of limiting the protection scope of the present invention.

[0040] In order to make the technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0041] Figure 1 It is a schematic diagram of a carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to an embodiment of the utility model.

[0042] like Figure 1As shown, one embodiment of the utility model provides a carbon capture liquefaction and dry ice preparation system based on LNG cold energy, comprising: a carbon capture unit and a liquefaction and dry ice preparation unit, the carbon capture unit is configured to adsorb and desorb carbon dioxide, and the carbon dioxide desorbed by the carbon capture unit enters the liquefaction and dry ice preparation unit;

[0043] Among them, the hot water of the solar thermal unit is used as the heat source of the carbon capture unit, the closed-loop cooling water of the gas-steam combined cycle unit is used as the cold source of the carbon capture unit, and the cold energy generated by the LNG gasification process is used as the cold energy of the liquefaction and dry ice preparation unit.

[0044] The carbon capture liquefaction and dry ice preparation system of this embodiment includes a carbon capture unit and a liquefaction and dry ice preparation unit. The carbon capture unit is used to capture carbon dioxide generated after combustion, adsorb and desorb carbon dioxide, and the desorbed carbon dioxide enters the liquefaction and dry ice preparation unit to provide raw materials for the preparation of dry ice, thereby avoiding direct emission of carbon dioxide into the atmosphere to cause pollution, and there is no need to seal carbon dioxide in underground oil layers to avoid occupying the oil layer area; at the same time, the hot water of the photothermal unit is used as the heat source of the carbon capture unit, and the closed-loop cooling water of the gas-steam combined cycle unit is used as the cold source of the carbon capture unit, so that the energy of the cold source and the heat source can be fully utilized to improve the energy utilization rate. The cold energy generated by the LNG gasification process is used as the cold energy of the liquefaction and dry ice preparation unit, which, on the one hand, realizes the cascade utilization of energy and improves the energy utilization rate, and on the other hand, can also avoid the generation of cold energy pollution to a certain extent, thereby improving the environmental protection of the system.

[0045] Specifically, the carbon capture unit collects flue gas after combustion and adsorbs carbon dioxide in the flue gas, that is, it achieves the adsorption of carbon dioxide. When it is necessary to desorb carbon dioxide, it is connected to the liquefaction and dry ice preparation unit, and the carbon dioxide is transported to the liquefaction and dry ice preparation unit as a raw material. The liquefied liquid carbon dioxide is stored by the liquefaction and dry ice preparation unit. When dry ice needs to be made, liquid carbon dioxide is used as a raw material for preparing dry ice. The entire system can achieve a step-by-step use of the energy of each unit, and convert carbon dioxide in the system to prevent carbon dioxide from being discharged into the atmosphere and polluting the air. At the same time, the liquefied liquid carbon dioxide is used as a raw material for dry ice to avoid the storage of carbon dioxide occupying too much area.

[0046] In one possible embodiment, the carbon capture unit comprises:

[0047] The first adsorption tower 5.1, the first air inlet of the first adsorption tower 5.1 is connected to the exhaust gas P3 at the waste heat boiler outlet, the first liquid inlet and the first liquid outlet of the first adsorption tower 5.1 are both connected to the photothermal unit, the first liquid inlet and the first liquid outlet are also connected to the gas-steam combined cycle unit, and the first air outlet of the first adsorption tower 5.1 is respectively connected to the liquefaction and dry ice preparation unit and the unit exhaust flue P5;

[0048] The second adsorption tower 5.2, the second air inlet of the second adsorption tower 5.2 is connected to the exhaust gas P3 at the waste heat boiler outlet, the second liquid inlet and the second liquid outlet of the second adsorption tower 5.2 are both connected to the photothermal unit, the second liquid inlet and the second liquid outlet are also connected to the gas-steam combined cycle unit, and the second air outlet of the second adsorption tower 5.2 is respectively connected to the liquefaction and dry ice preparation unit and the unit exhaust flue P5;

[0049] Herein, connectivity refers to connectivity through pipelines.

[0050] It should be noted that the carbon capture unit usually includes two adsorption towers, namely the first adsorption tower 5.1 and the second adsorption tower 5.2. Usually, the first adsorption tower 5.1 and the second adsorption tower 5.2 are used alternately, that is, when the first adsorption tower 5.1 is adsorbing carbon dioxide from the flue gas, the second adsorption tower 5.2 is desorbing carbon dioxide; when the first adsorption tower 5.1 is desorbing carbon dioxide, the first adsorption tower 5.1 is adsorbing carbon dioxide from the flue gas.

[0051] Among them, the first adsorption tower 5.1 and the second adsorption tower 5.2 adsorb carbon dioxide at a temperature of 60°C to 70°C, and the first adsorption tower 5.1 and the second adsorption tower 5.2 desorb carbon dioxide at a temperature of 110°C to 120°C. This embodiment uses the closed-loop cooling water of the gas-steam combined cycle unit as a cold source for carbon dioxide adsorption, and uses the hot water of the photothermal unit as a heat source for carbon dioxide desorption, which can improve the step-by-step utilization of the energy of the gas-steam combined cycle unit and the photothermal unit without the need to additionally set up a cold source and a heat source, thereby improving energy utilization.

[0052] Optionally, by connecting the first air inlet and the second air inlet to the exhaust gas P3 at the exhaust heat boiler outlet, the carbon dioxide in the exhaust heat boiler outlet exhaust gas P3 can be treated to avoid carbon dioxide being discharged into the atmosphere and increasing the pace of global warming, thereby ensuring the environmental friendliness of the entire system.

[0053] In a feasible embodiment, a fifth flue gas damper 4.5 is provided between the first air inlet and the flue gas P3 at the waste heat boiler outlet, a sixth flue gas damper 4.6 is provided between the second air inlet and the flue gas P3 at the waste heat boiler outlet, a fourth flue gas damper 4.4 is provided between the first air outlet and the unit exhaust flue P5, a second flue gas damper 4.2 is provided between the second air outlet and the unit exhaust flue P5, a third flue gas damper 4.3 is provided between the first air outlet and the liquefaction and dry ice preparation unit, and a first flue gas damper 4.1 is provided between the second air outlet and the liquefaction and dry ice preparation unit;

[0054] Among them, the smoke damper is configured to control the flow of gas.

[0055] It can be understood that by setting the flue gas damper, it is controlled whether the flue gas enters the first adsorption tower 5.1 and the second adsorption tower 5.2, and whether the flue gas is discharged from the first adsorption tower 5.1 and the second adsorption tower 5.2 to the liquefaction and dry ice preparation unit, and whether the flue gas is discharged from the first adsorption tower 5.1 and the second adsorption tower 5.2 to the unit exhaust duct P5.

[0056] Specifically, when the first adsorption tower 5.1 is adsorbing carbon dioxide, the fifth flue gas damper 4.5 and the fourth flue gas damper 4.4 are opened. At this time, the second adsorption tower 5.2 is desorbing carbon dioxide, the first flue gas damper 4.1 is opened, and the other flue gas dampers are closed; similarly, when the second adsorption tower 5.2 is adsorbing carbon dioxide, the sixth flue gas damper 4.6 and the second flue gas damper 4.2 are opened. At this time, the first adsorption tower 5.1 is desorbing carbon dioxide, the third flue gas damper 4.3 is opened, and the other flue gas dampers are closed.

[0057] In a feasible implementation manner, the gas-steam combined cycle unit comprises a cooling water intake port P10 and a cooling water return port P9, the cooling water intake port P10 is respectively connected to the first liquid inlet and the second liquid inlet, and the cooling water return port P9 is respectively connected to the first liquid outlet and the second liquid outlet;

[0058] A first plate heat exchanger 12.1 is provided at the cooling water intake port P10 and the cooling water return port P9, and a first booster pump 11.1 is also provided on the pipeline of the cooling water intake port.

[0059] The temperature in the first adsorption tower 5.1 and the second adsorption tower 5.2 is lowered by the cooling circulating water of the gas-steam combined cycle unit, so that the temperature in the first adsorption tower 5.1 and the second adsorption tower 5.2 reaches 60°C to 70°C, which facilitates the first adsorption tower 5.1 and the second adsorption tower 5.2 to adsorb carbon dioxide in the flue gas and fully absorb the carbon dioxide in the flue gas P3 at the outlet of the waste heat boiler.

[0060] In a feasible embodiment, a sixth regulating valve 10.6 is provided between the first booster pump 11.1 and the first liquid inlet, a fifth regulating valve 10.5 is provided between the first booster pump 11.1 and the second liquid inlet, a third regulating valve 10.3 is provided between the first liquid outlet and the first plate heat exchanger 12.1, and a fourth regulating valve 10.4 is provided between the second liquid outlet and the first plate heat exchanger 12.1.

[0061] The first booster pump 11.1 is provided to facilitate water from the cooling water inlet P10 to enter the first adsorption tower 5.1 and the second adsorption tower 5.2, that is, the cold water from the cooling water inlet P10 is transported to the first adsorption tower 5.1 through the sixth regulating valve 10.6, or the cold water is transported to the second adsorption tower 5.2 through the fifth regulating valve 10.5. After the cold water passes through the first adsorption tower 5.1 or the second adsorption tower 5.2, it is heated up, returns to the first plate heat exchanger 12.1 for cooling, and then returns to the gas-steam combined cycle unit through the cooling water return port P9.

[0062] It can be understood that, since the adsorption and desorption of carbon dioxide by the first adsorption tower 5.1 and the second adsorption tower 5.2 are performed alternately, the third regulating valve 10.3 and the sixth regulating valve 10.6 are opened at the same time, and the fifth regulating valve 10.5 and the fourth regulating valve 10.4 are closed; similarly, when the fifth regulating valve 10.5 and the fourth regulating valve 10.4 are opened, the third regulating valve 10.3 and the sixth regulating valve 10.6 are closed.

[0063] In a feasible embodiment, the photothermal unit includes a high-temperature water outlet P7 and a high-temperature water return port P8, the high-temperature water outlet P7 is respectively connected to the first liquid inlet and the second liquid inlet, and the high-temperature water return port P8 is respectively connected to the first liquid outlet and the second liquid outlet;

[0064] A second plate heat exchanger 12.2 is provided at the high-temperature water outlet P7 and the high-temperature water return port P8, and a second booster pump 11.2 is provided on the pipeline of the high-temperature water outlet P7.

[0065] The temperature in the first adsorption tower 5.1 and the second adsorption tower 5.2 is increased by the hot water of the photothermal unit, so that the temperature in the first adsorption tower 5.1 and the second adsorption tower 5.2 reaches 110°C to 120°C, which facilitates the desorption of carbon dioxide in the first adsorption tower 5.1 and the second adsorption tower 5.2 and achieves sufficient desorption of carbon dioxide.

[0066] In a feasible embodiment, an eighth regulating valve 10.8 is provided between the second booster pump 11.2 and the first liquid inlet, a seventh regulating valve 10.7 is provided between the second booster pump 11.2 and the second liquid inlet, a second regulating valve is provided between the first liquid outlet and the second plate heat exchanger 12.2, and a first regulating valve 10.1 is provided between the second liquid outlet and the second plate heat exchanger 12.2.

[0067] Among them, the setting of the second booster pump 11.2 facilitates the hot water at the high-temperature water outlet P7 to enter the first adsorption tower 5.1 and the second adsorption tower 5.2, that is, the hot water at the high-temperature water outlet P7 is transported to the first adsorption tower 5.1 through the eighth regulating valve 10.8, or the hot water is transported to the second adsorption tower 5.2 through the seventh regulating valve 10.7. After the hot water passes through the first adsorption tower 5.1 or the second adsorption tower 5.2, it is cooled down and returns to the second plate heat exchanger 12.2 to heat up and then returns to the photothermal unit through the high-temperature water outlet P7.

[0068] It can be understood that since the adsorption and desorption of carbon dioxide by the first adsorption tower 5.1 and the second adsorption tower 5.2 are performed alternately, the seventh regulating valve and the first regulating valve 10.1 are opened at the same time, and the seventh regulating valve 10.7 and the second regulating valve are closed; similarly, when the seventh regulating valve 10.7 and the second regulating valve are opened, the eighth regulating valve 10.8 and the first regulating valve 10.1 are closed.

[0069] Specifically, the working principle of the carbon capture unit is described in detail herein, as described below.

[0070] When the first adsorption tower 5.1 is adsorbing carbon dioxide, the fifth flue gas damper 4.5 and the fourth flue gas damper 4.4 are in the open state, and the third flue gas damper 4.3 is in the closed state. The residual gas after adsorption by the first adsorption tower 5.1 is discharged into the unit exhaust flue P5 through the fourth flue gas damper 4.4. At this time, the eighth regulating valve 10.8 and the first regulating valve 10.1 are closed, the sixth regulating valve 10.6 and the third regulating valve 10.3 are opened, and the closed-circulation cooling water of the gas-steam combined cycle unit is used to cool the environment in the first adsorption tower 5.1 to reach the temperature for adsorbing carbon dioxide. (60℃ to 70℃) requirement; at this time, the second adsorption tower 5.2 desorbs carbon dioxide, the sixth flue gas damper 4.6 and the second flue gas damper 4.2 are closed, and the first flue gas damper 4.1 is opened, and the carbon dioxide desorbed by the second desorption tower is transported to the liquefaction and dry ice preparation unit for subsequent treatment. At this time, the first regulating valve 10.1 and the second regulating valve are opened, the fifth regulating valve 10.5 and the fourth regulating valve 10.4 are closed, and the hot water of the photothermal unit is used to heat the environment in the second adsorption tower 5.2 so as to meet the temperature requirement (110℃ to 120℃) for desorption of carbon dioxide.

[0071] When the first adsorption tower 5.1 is desorbing carbon dioxide, the fourth flue gas damper 4.4 and the fifth flue gas damper 4.5 are closed, and the third flue gas damper 4.3 is opened, and the carbon dioxide desorbed by the first desorption tower is transported to the liquefaction and dry ice preparation unit for subsequent treatment. At this time, the first regulating valve 10.1 and the eighth regulating valve 10.8 are opened, and the third regulating valve 10.3 and the sixth regulating valve 10.6 are closed, and the hot water of the photothermal unit is used to heat the environment in the first adsorption tower 5.1 to meet the temperature requirement (110°C to 120°C) for desorption of carbon dioxide; at this time, the second adsorption tower 5 .2 for the adsorption of carbon dioxide, the sixth flue gas damper 4.6 and the second flue gas damper 4.2 are in the open state, the first flue gas damper 4.1 is in the closed state, and the residual gas after adsorption by the second adsorption tower 5.2 is discharged into the unit exhaust flue P5 through the second flue gas damper 4.2. At this time, the seventh regulating valve 10.7 and the second regulating valve are closed, the fifth regulating valve 10.5 and the fourth regulating valve 10.4 are opened, and the closed-circulation cooling water of the gas-steam combined cycle unit is used to cool the environment in the second adsorption tower 5.2 so as to meet the temperature requirement (60°C to 70°C) for the adsorption of carbon dioxide.

[0072] It should be noted that by setting up two adsorption towers and alternately adsorbing and desorbing carbon dioxide, the working efficiency of the system can be improved without stopping the system to wait for the adsorption and desorption process, thereby improving the working efficiency of the system and the efficiency of treating carbon dioxide.

[0073] It can be understood that a first heat exchanger regulating valve 18.1 is provided between the cooling water return port P9 and the first plate heat exchanger 12.1, a second heat exchanger regulating valve 18.2 is provided between the cooling water intake port P10 and the first plate heat exchanger 12.1, a third heat exchanger regulating valve 18.3 is provided between the high-temperature water return port P8 and the second plate heat exchanger 12.2, and a fourth heat exchanger regulating valve 18.4 is provided between the high-temperature water outlet P7 and the second plate heat exchanger 12.2. The amount of hot water and cold water entering and flowing out is controlled by the heat exchanger regulating valves, which will not be elaborated.

[0074] In a feasible embodiment, the liquefaction and dry ice preparation unit comprises:

[0075] a first compressor 2.1, wherein a first inlet of the first compressor 2.1 is used to receive carbon dioxide released by the carbon capture unit;

[0076] A first heat exchanger 3.1, the inlet of the first heat exchanger 3.1 is connected to the first outlet of the first compressor 2.1, and the outlet of the first heat exchanger 3.1 is also connected to the combustion chamber P4 of the gas turbine and the exhaust duct P5 of the unit;

[0077] A second heat exchanger 3.2, the outlet of the second heat exchanger 3.2 is connected to the inlet of the gas-liquid separator 7, the outlet of the gas-liquid separator 7 is connected to the inlet of the first heat exchanger 3.1, and the outlet of the gas-liquid separator 7 is also connected to the liquid storage tank 8;

[0078] a second compressor 2.2, wherein a second inlet of the second compressor 2.2 is connected to an outlet of the first heat exchanger 3.1, and a second outlet of the second compressor 2.2 is connected to an inlet of the second heat exchanger 3.2;

[0079] The inlet of the first heat exchanger 3.1 and the inlet of the second heat exchanger 3.2 are both connected to the LNG outlet P6, a first gas flow valve 6.1 is provided between the LNG outlet P6 and the first heat exchanger 3.1, and a second gas flow valve 6.2 is provided between the LNG outlet P6 and the second heat exchanger 3.2.

[0080] It should be noted that the carbon dioxide adsorbed by the first adsorption tower 5.1 or the second adsorption tower 5.2 enters the first compressor 2.1 after desorption, first increases the pressure of the carbon dioxide and then enters the first heat exchanger 3.1, and at the same time enters the first heat exchanger 3.1 with the outlet gas of the second heat exchanger 3.2 and the gaseous substance discharged by the gas-liquid separator 7, and exchanges heat with the carbon dioxide for cooling. The cooled carbon dioxide enters the second compressor 2.2 from the first heat exchanger 3.1 for further compression. After the carbon dioxide is compressed and pressurized by the second compressor 2.2, it enters the second heat exchanger 3.2 for further cooling and then enters the gas-liquid separator 7 for gas-liquid separation. The gaseous substance (i.e., impurity gas) obtained by the gas-liquid separator 7 enters the first heat exchanger 3.1 to recover excess cold energy and then is discharged into the unit exhaust flue P5. The liquid carbon dioxide obtained by the gas-liquid separator 7 flows to the liquid storage tank 8 for storage.

[0081] It is understandable that converting gaseous carbon dioxide into liquid carbon dioxide can, on the one hand, prevent gaseous carbon dioxide from being discharged into the air and causing pollution to the atmosphere; on the other hand, liquid carbon dioxide is easy to store and can also provide raw materials for the preparation of dry ice, avoiding the storage of liquid carbon dioxide taking up too much space.

[0082] Among them, the cold energy of the liquefaction and dry ice preparation unit comes from the cold energy generated by the LNG gasification process. The liquefied natural gas at the LNG outlet P6 is respectively passed into the first flow valve and the second flow valve through the parallel pipeline. The liquefied natural gas enters the second heat exchanger 3.2 through the second flow valve to be heated and vaporized. The heated liquefied natural gas is mixed with the liquefied natural gas passing through the first flow valve and then passed into the first heat exchanger 3.1 after temperature adjustment. After heat exchange and temperature increase in the first heat exchanger 3.1, the liquefied natural gas enters the combustion chamber P4 of the gas turbine. After entering the combustion chamber of the gas turbine for combustion, the liquefied natural gas drives the steam turbine to work. Such a setting can provide cold energy for the first heat exchanger 3.1 and the second heat exchanger 3.2, and can realize the step-by-step utilization of energy in LNG gasification.

[0083] In a feasible embodiment, the liquefaction and dry ice preparation unit further includes:

[0084] A dry ice machine 14 is connected to the outlet of the liquid storage tank 8, and a liquid carbon dioxide regulating valve 16 is provided between the dry ice machine 14 and the liquid storage tank 8;

[0085] The gas storage tank 15 has an inlet connected to the gaseous carbon dioxide outlet of the dry ice machine 14, and an outlet connected to the first inlet of the first compressor 2.1. A gaseous carbon dioxide regulating valve 17 is provided between the gas storage tank 15 and the first compressor 2.1.

[0086] Optionally, when dry ice preparation is required, the liquid carbon dioxide regulating valve 16 is opened, and the liquid carbon dioxide in the liquid storage tank 8 is passed into the dry ice machine 14 for preparation of dry ice. The gaseous carbon dioxide generated by evaporation during the preparation process is passed into the gas storage tank 15. When the carbon dioxide in the gas storage tank 15 reaches a certain amount, it passes through the gaseous carbon dioxide regulating valve 17 and re-enters the first compressor 2.1 for compression. The subsequent process is as described above and will not be repeated here.

[0087] It should be noted that by connecting with the dry ice machine 14, the rational use of liquid carbon dioxide can be achieved. On the one hand, it can avoid too much liquid carbon dioxide occupying too much storage space. On the other hand, it can also achieve rational utilization of carbon dioxide, avoid carbon dioxide being released into the air to cause pollution, and improve the environmental friendliness of the system.

[0088] In a feasible embodiment, the liquefaction and dry ice preparation unit further includes:

[0089] Small steam turbine 1, the inlet of small steam turbine 1 is connected with the outlet steam P1 of waste heat boiler, the first outlet of small steam turbine 1 is connected with condenser P2, small steam turbine 1 is connected with the crankshaft connecting rod of first compressor 2.1 and second compressor 2.2 respectively through shaft chain, small steam turbine 1 provides rotational kinetic energy for first compressor 2.1 and second compressor 2.2.

[0090] It should be noted that the steam P1 at the outlet of the waste heat boiler is high-pressure steam, and the small steam turbine 1 returns to the condenser P2 after doing work. This is a normal process of thermal power companies and will not be mentioned here.

[0091] In the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0092] Those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the present invention disclosed herein. The present invention is intended to cover any variation, use, or adaptation of the present invention that follows the general principles of the present invention and includes common knowledge or customary technical means in the art that are not disclosed in the present invention. The specification and examples are to be regarded as exemplary only.

[0093] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A carbon capture liquefaction and dry ice preparation system based on LNG cold energy, characterized in that: include: A carbon capture unit and a liquefaction and dry ice preparation unit, wherein the carbon capture unit is configured to adsorb and desorb carbon dioxide, and the carbon dioxide desorbed by the carbon capture unit enters the liquefaction and dry ice preparation unit; Among them, the hot water of the photothermal unit is used as the heat source of the carbon capture unit, the closed-loop cooling water of the gas-steam combined cycle unit is used as the cold source of the carbon capture unit, and the cold energy generated by the LNG gasification process is used as the cold energy of the liquefaction and dry ice preparation unit.

2. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 1 is characterized in that: The carbon capture unit comprises: A first adsorption tower, wherein the first air inlet of the first adsorption tower is connected to the flue gas at the waste heat boiler outlet, the first liquid inlet and the first liquid outlet of the first adsorption tower are both connected to the photothermal unit, the first liquid inlet and the first liquid outlet are also both connected to the gas-steam combined cycle unit, and the first air outlet of the first adsorption tower is respectively connected to the liquefaction and dry ice preparation unit and the unit exhaust flue; A second adsorption tower, wherein the second air inlet of the second adsorption tower is connected to the flue gas at the waste heat boiler outlet, the second liquid inlet and the second liquid outlet of the second adsorption tower are both connected to the photothermal unit, the second liquid inlet and the second liquid outlet are also both connected to the gas-steam combined cycle unit, and the second air outlet of the second adsorption tower is respectively connected to the liquefaction and dry ice preparation unit and the exhaust flue of the unit; The communication refers to communication through a pipeline.

3. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 2 is characterized in that: A fifth flue gas damper is provided between the first air inlet and the flue gas at the waste heat boiler outlet, a sixth flue gas damper is provided between the second air inlet and the flue gas at the waste heat boiler outlet, a fourth flue gas damper is provided between the first air outlet and the unit exhaust duct, a second flue gas damper is provided between the second air outlet and the unit exhaust duct, a third flue gas damper is provided between the first air outlet and the liquefaction and dry ice preparation unit, and a first flue gas damper is provided between the second air outlet and the liquefaction and dry ice preparation unit; Wherein, the smoke damper is configured to control the flow of gas.

4. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 2 is characterized in that: The gas-steam combined cycle unit comprises a cooling water intake and a cooling water return port, wherein the cooling water intake is respectively connected to the first liquid inlet and the second liquid inlet, and the cooling water return port is respectively connected to the first liquid outlet and the second liquid outlet; A first plate heat exchanger is provided at the cooling water intake and the cooling water return port, and a first booster pump is also provided on the pipeline of the cooling water intake.

5. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 4 is characterized in that: A sixth regulating valve is provided between the first booster pump and the first liquid inlet, a fifth regulating valve is provided between the first booster pump and the second liquid inlet, a third regulating valve is provided between the first liquid outlet and the first plate heat exchanger, and a fourth regulating valve is provided between the second liquid outlet and the first plate heat exchanger.

6. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 2 is characterized in that: The photothermal unit comprises a high-temperature water outlet and a high-temperature water return port, wherein the high-temperature water outlet is communicated with the first liquid inlet and the second liquid inlet respectively, and the high-temperature water return port is communicated with the first liquid outlet and the second liquid outlet respectively; A second plate heat exchanger is provided at the high-temperature water outlet and the high-temperature water return port, and a second booster pump is provided on the pipeline of the high-temperature water outlet.

7. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 6, characterized in that: An eighth regulating valve is provided between the second booster pump and the first liquid inlet, a seventh regulating valve is provided between the second booster pump and the second liquid inlet, a second regulating valve is provided between the first liquid outlet and the second plate heat exchanger, and a first regulating valve is provided between the second liquid outlet and the second plate heat exchanger.

8. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 1, characterized in that: The liquefaction and dry ice preparation unit comprises: a first compressor, wherein a first inlet of the first compressor is used to receive carbon dioxide released by the carbon capture unit; A first heat exchanger, wherein the inlet of the first heat exchanger is connected to the first outlet of the first compressor, and the outlet of the first heat exchanger is also connected to the combustion chamber of the gas turbine and the exhaust duct of the unit respectively; a second heat exchanger, wherein the outlet of the second heat exchanger is connected to the inlet of the gas-liquid separator, the outlet of the gas-liquid separator is connected to the inlet of the first heat exchanger, and the outlet of the gas-liquid separator is also connected to the liquid storage tank; a second compressor, wherein a second inlet of the second compressor is connected to an outlet of the first heat exchanger, and a second outlet of the second compressor is connected to an inlet of the second heat exchanger; The inlet of the first heat exchanger and the inlet of the second heat exchanger are both connected to the LNG outlet, a first gas flow valve is provided between the LNG outlet and the first heat exchanger, and a second gas flow valve is provided between the LNG outlet and the second heat exchanger.

9. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 8, characterized in that: The liquefaction and dry ice preparation unit also includes: A dry ice machine is connected to the outlet of the liquid storage tank, and a liquid carbon dioxide regulating valve is provided between the dry ice machine and the liquid storage tank; A gas storage tank, wherein the inlet of the gas storage tank is connected to the gaseous carbon dioxide outlet of the dry ice machine, the outlet of the gas storage tank is connected to the first inlet of the first compressor, and a gaseous carbon dioxide regulating valve is provided between the gas storage tank and the first compressor.

10. The carbon capture liquefaction and dry ice preparation system based on LNG cold energy according to claim 8, characterized in that: The liquefaction and dry ice preparation unit also includes: A small steam turbine, wherein the inlet of the small steam turbine is connected to the outlet steam of the waste heat boiler, the first outlet of the small steam turbine is connected to the condenser, and the small steam turbine is connected to the crankshaft connecting rods of the first compressor and the second compressor respectively through a shaft chain, and the small steam turbine provides rotational kinetic energy for the first compressor and the second compressor.

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