Liquid carbon dioxide and supercritical carbon dioxide co-production system and method

Abstract

The invention relates to a liquid carbon dioxide and supercritical carbon dioxide co-production system and method. The system comprises a compression unit, a first refrigeration unit and a second refrigeration unit, wherein the first refrigeration unit and the second refrigeration unit are respectively connected with the compression unit; the compression unit is used for compressing and cooling gaseous carbon dioxide, shunting the processed gaseous carbon dioxide to obtain a first stream and a second stream, and transmitting the first stream to the first refrigeration unit; the first refrigeration unit is used for cooling the first stream to obtain liquid carbon dioxide; the compression unit is used for compressing and cooling the second stream to obtain supercritical carbon dioxide, and part of supercritical carbon dioxide in the supercritical carbon dioxide is extracted and conveyed to the second refrigeration unit; and the second refrigeration unit is used for carrying out expansion treatment on the input supercritical carbon dioxide to obtain cold supply carbon dioxide and enabling the carbon dioxide to flow back to the compression unit. The method is favorable for reducing the energy consumption of the system.

Description

Technical Field

[0001] The present application relates to the field of gas processing technology, and in particular to a liquid carbon dioxide and supercritical carbon dioxide co-production system, as well as a liquid carbon dioxide and supercritical carbon dioxide co-production method, device, computer equipment, computer-readable storage medium and computer program product. Background Art

[0002] Depending on the form of CO2 utilization, the state of CO2 products is divided into liquid (industrial / food grade CO2) and supercritical state (oil recovery / storage).

[0003] Currently, the production of liquid CO2 often uses a compression-cryogenic liquefaction process. For CO2 storage (using engineering techniques to transport CO2 to a designated location and inject it into underground saline aquifers, either onshore or underwater, for long-term storage and carbon reduction), a multi-stage compression process is typically used to compress CO2 to a critical pressure of 7.38 MPa (megapascals) or higher, and then transport it via a critical-state CO2 pipeline. A cooler is required between each compression stage to ensure the gas temperature remains within a reasonable range, ensuring proper compressor operation and improving compression efficiency. However, when the compressor is subjected to variable load regulation, some CO2 often needs to be refluxed to the compressor inlet to maintain suction flow, resulting in increased compression energy consumption during variable load conditions. Summary of the Invention

[0004] Based on this, it is necessary to provide a liquid carbon dioxide and supercritical carbon dioxide co-production system that can reduce system energy consumption, as well as a liquid carbon dioxide and supercritical carbon dioxide co-production method, device, computer equipment, computer-readable storage medium and computer program product to address the above technical problems.

[0005] In a first aspect, the present application provides a system for co-producing liquid carbon dioxide and supercritical carbon dioxide, the system comprising a compression unit, and a first refrigeration unit and a second refrigeration unit respectively connected to the compression unit:

[0006] a compression unit for compressing and cooling the gaseous carbon dioxide, splitting the treated gaseous carbon dioxide into a first stream and a second stream, and transmitting the first stream to the first refrigeration unit;

[0007] a first refrigeration unit, configured to cool the first stream to obtain liquid carbon dioxide;

[0008] a compression unit for compressing and cooling the second stream to obtain supercritical carbon dioxide, extracting a portion of the supercritical carbon dioxide and transmitting it to a second refrigeration unit;

[0009] The second refrigeration unit is used to expand the input supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the compression unit.

[0010] In one embodiment, the first refrigeration unit includes a first liquefier, and a gas-liquid separator, a refrigerant compressor, an oil separator, and a condenser connected to the first liquefier in sequence, the output end of the condenser is connected to the first liquefier, and the first liquefier is connected to the compression unit.

[0011] In one embodiment, the second refrigeration unit includes an expander and a second liquefier, the input end of the expander is connected to the interstage of the compression unit, and the second liquefier is connected to the input end of the compressor of the compression unit. The expander is used to expand the extracted part of the supercritical carbon dioxide, recover the energy generated during the expansion process, and reduce the temperature of the extracted part of the supercritical carbon dioxide to provide cooling capacity for the second liquefier.

[0012] In one embodiment, the compression unit includes a compressor, an interstage cooler, and a gearbox connected to each other.

[0013] In one embodiment, the compression unit includes a multi-stage compressor, multiple interstage coolers and multiple gearboxes. The multi-stage compressors are connected in sequence through multiple drive shafts, and a gearbox and an interstage cooler are provided between each drive shaft and the main shaft of each stage of the compressor.

[0014] In one embodiment, the system further includes a first regulating valve and a second regulating valve, and the first stream includes a first split stream and a second split stream;

[0015] The first regulating valve is provided between the compression unit and the first liquefier, and is used to adjust the flow rate of the first split flow;

[0016] The second regulating valve is arranged between the compression unit and the second liquefier, and is used for adjusting the flow rate of the second branch flow.

[0017] In one embodiment, the first liquefier is used to liquefy the first fraction to obtain liquid carbon dioxide;

[0018] The second liquefier is used to liquefy the second branch flow to obtain liquid carbon dioxide.

[0019] In one embodiment, the system further includes a third regulating valve, which is disposed between the compression unit and the expander and is configured to transfer a portion of the supercritical carbon dioxide to the expander of the second refrigeration unit.

[0020] In one embodiment, the system further includes a controller, the first refrigeration unit, the second refrigeration unit, and the compression unit are respectively connected to the controller, the controller being configured to control the compression unit to compress and cool the gaseous carbon dioxide in response to a co-generation control instruction, and to split the treated gaseous carbon dioxide into a first stream and a second stream;

[0021] controlling the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide;

[0022] controlling the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extracting a portion of the supercritical carbon dioxide;

[0023] The second refrigeration unit is controlled to expand part of the extracted supercritical carbon dioxide to obtain cooling carbon dioxide, and the cooling carbon dioxide is refluxed to the second stream.

[0024] In a second aspect, the present application further provides a method for co-producing liquid carbon dioxide and supercritical carbon dioxide, which is applied to any of the above-mentioned liquid carbon dioxide and supercritical carbon dioxide co-production systems, and the method comprises:

[0025] In response to the co-generation control instruction, controlling the compression unit to compress and cool the gaseous carbon dioxide, and splitting the treated gaseous carbon dioxide into a first stream and a second stream;

[0026] controlling the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide;

[0027] controlling the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extracting a portion of the supercritical carbon dioxide;

[0028] The second refrigeration unit is controlled to expand part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and the cooling carbon dioxide is refluxed to the second stream.

[0029] In a third aspect, the present application further provides a device for co-producing liquid carbon dioxide and supercritical carbon dioxide, comprising:

[0030] a compression control module, configured to control a compression unit to compress and cool the gaseous carbon dioxide, split the treated gaseous carbon dioxide into a first stream and a second stream, control the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extract a portion of the supercritical carbon dioxide from the supercritical carbon dioxide;

[0031] a cooling control module, configured to control the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide;

[0032] The expansion control module is used to control the second refrigeration unit to expand part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the second stream.

[0033] In a fourth aspect, the present application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the steps in any one of the above-mentioned embodiments of the method for co-production of liquid carbon dioxide and supercritical carbon dioxide.

[0034] In a fifth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in any one of the above-mentioned embodiments of the method for co-production of liquid carbon dioxide and supercritical carbon dioxide.

[0035] In a sixth aspect, the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps in any one of the above-mentioned embodiments of the method for co-production of liquid carbon dioxide and supercritical carbon dioxide.

[0036] The above-mentioned liquid carbon dioxide and supercritical carbon dioxide co-production system, on the one hand, provides an integrated liquid carbon dioxide and supercritical carbon dioxide co-production system, which uses a set of equipment to simultaneously produce liquid carbon dioxide and supercritical carbon dioxide, reducing the power consumption of the compression unit, improving the flexibility of the system, and at the same time, reducing the number of compression units, reducing investment costs and occupied area; on the other hand, considering that during the preparation process, when the compression unit is load-adjusted, the energy consumption increased by reflowing part of the carbon dioxide to the compression unit inlet to ensure the suction flow of the compression unit, part of the supercritical carbon dioxide produced by the compression unit is expanded, and part of the mechanical energy is recovered through the expansion process, thereby reducing power consumption. The cooling carbon dioxide obtained after the expansion process is reflowed to the compression unit to form a cycle, which helps to maintain the flow stability of the system, optimize the system preparation efficiency, and reduce the system energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A structural block diagram of a liquid carbon dioxide and supercritical carbon dioxide co-production system in one embodiment;

[0039] Figure 2A schematic diagram of a system for co-producing liquid carbon dioxide and supercritical carbon dioxide in one embodiment;

[0040] Figure 3 A structural block diagram of a method for co-producing liquid carbon dioxide and supercritical carbon dioxide in another embodiment;

[0041] Figure 4 A diagram showing the application environment of a method for co-producing liquid carbon dioxide and supercritical carbon dioxide in one embodiment;

[0042] Figure 5 Schematic diagram of a process for co-producing liquid carbon dioxide and supercritical carbon dioxide in one embodiment;

[0043] Figure 6 This is a structural block diagram of a liquid carbon dioxide and supercritical carbon dioxide co-production device in one embodiment;

[0044] Figure 7 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0046] In an exemplary embodiment, Figure 1 As shown, a system for co-producing liquid carbon dioxide and supercritical carbon dioxide is provided, comprising a compression unit 100, and a first refrigeration unit 200 and a second refrigeration unit 300 respectively connected to the compression unit.

[0047] The compression unit 100 is used to compress and cool the gaseous carbon dioxide, split the treated gaseous carbon dioxide into a first stream and a second stream, and transmit the first stream to the first refrigeration unit 200 .

[0048] The first stream is used to produce liquid carbon dioxide, while the second stream is used to produce supercritical carbon dioxide. Supercritical carbon dioxide refers to the state of matter formed when carbon dioxide is above its critical temperature (31.1°C) and critical pressure (7.38 MPa).

[0049] In practical applications, the compression unit may receive gaseous carbon dioxide from a gas source, such as industrial waste gas, combustion emissions, or natural gas fields, and compress and cool the gaseous carbon dioxide through a diversion device (such as a diversion valve). The treated gaseous carbon dioxide is then diverted to obtain two streams of gaseous carbon dioxide, namely, a first stream and a second stream. For example, Figure 2 As shown, after the gaseous carbon dioxide is compressed and cooled, the pressure of the obtained gaseous carbon dioxide reaches 2.5 MPa and the temperature reaches 40°C. The gaseous carbon dioxide after the compression and cooling treatment is split, and the first stream 102 of the split is used to produce liquid carbon dioxide, and the other part ( Figure 2 Stream 103 in the process is used to produce supercritical carbon dioxide. Before processing the gaseous carbon dioxide, the captured carbon dioxide undergoes purification pretreatment to remove impurities. This purification pretreatment may include at least one of filtration, drying, and desulfurization and denitrification. Filtration may remove dust and other suspended particulate matter from the gaseous carbon dioxide. Drying may remove water vapor from the gaseous carbon dioxide. Desulfurization and denitrification may remove sulfur oxides and nitrogen oxides from the gaseous carbon dioxide.

[0050] The first refrigeration unit 200 is used to cool the first stream to obtain liquid carbon dioxide.

[0051] In practical applications, the first refrigeration unit may cool the first stream to reduce its temperature to below the liquefaction temperature (eg, below -25°C), reaching the dew point and converting it into liquid to obtain liquid carbon dioxide.

[0052] The compression unit 100 is used to compress and cool the second stream to obtain supercritical carbon dioxide, and extract part of the supercritical carbon dioxide to transmit it to the second refrigeration unit 300.

[0053] In practical applications, the compression unit may include multiple compressors connected in series, or may include a device that gradually increases the gas pressure in stages, without specific limitation. The compression unit compresses and cools the second stream to achieve a supercritical state, that is, a pressure greater than 7.38 MPa and a temperature greater than 32°C. Supercritical carbon dioxide is obtained. When the compressor is subjected to variable load regulation, a portion of the supercritical carbon dioxide needs to be refluxed to the compression unit to ensure stable operation and efficiency of the compressor. Variable load regulation can be to adjust the amount of gas processed by the compressor (i.e., load) according to actual needs to match the needs of downstream processes or respond to changes in upstream supply. The compression unit transfers part of the supercritical carbon dioxide produced from the supercritical carbon dioxide to the second refrigeration unit for reflux through the second refrigeration unit.

[0054] The second refrigeration unit 300 is used to expand the input supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the compression unit 100.

[0055] The carbon dioxide used for cooling is the carbon dioxide that has been expanded.

[0056] In practical applications, the second refrigeration unit may include an expander and an extraction device. The expander may be a turbine expander, turbo expander, or the like. For example, the extraction device of the second refrigeration unit extracts a portion of the supercritical carbon dioxide from the compression unit for variable load regulation. The turbine expander then expands the supercritical carbon dioxide, reducing its pressure and rapidly lowering its temperature to produce cooling carbon dioxide. This also recovers some mechanical energy. The cooling carbon dioxide is then returned to the compressor inlet of the compression unit via a channel to accommodate variable load regulation.

[0057] In this embodiment, on the one hand, a co-production system integrating liquid carbon dioxide and supercritical carbon dioxide is provided, so that liquid carbon dioxide and supercritical carbon dioxide are produced simultaneously by using a set of equipment, thereby reducing the power consumption of the compression unit, improving the flexibility of the system, and at the same time, reducing the number of compression units, reducing the investment cost and the occupied area; on the other hand, considering the increase in energy consumption caused by the variable load adjustment of the compression unit during the preparation process, by reflowing part of the carbon dioxide to the inlet of the compression unit to ensure the suction flow of the compression unit, part of the supercritical carbon dioxide produced by the compression unit is expanded, and part of the mechanical energy is recovered through the expansion process, thereby reducing power consumption, and the cooling carbon dioxide obtained after the expansion process is recirculated to the compression unit to form a cycle, which helps to maintain the flow stability of the system, optimize the preparation efficiency of the system, and reduce energy consumption.

[0058] In an exemplary embodiment, the first refrigeration unit 200 includes a first liquefier, and a gas-liquid separator, a refrigerant compressor, an oil separator, and a condenser connected to the first liquefier in sequence, the output end of the condenser is connected to the first liquefier, and the first liquefier is connected to the compression unit 100.

[0059] In practical applications, such as Figure 2 As shown, the first refrigeration unit 200 includes a first liquefier, and a gas-liquid separator, a refrigerant compressor, an oil separator, and a condenser (not numbered in the figure) connected to the first liquefier in sequence. The output end of the condenser is connected to the first liquefier. The first liquefier is connected to the output end of the compressor in the compression unit 100. Through the gas-liquid separator, the refrigerant compressor, a series of processes by the separator and the condenser: the gas-liquid separator removes residual gas in the liquid carbon dioxide, the refrigerant compressor generates cold energy by compressing the refrigerant to reduce the temperature of the carbon dioxide, the oil separator separates the lubricating oil entrained in the refrigerant, and the condenser uses an external cooling medium (such as water or air) to take away the heat released by the refrigerant, cool it and liquefy it, and produce refrigerant, prompting the first liquefier to liquefy the first stream so that its temperature reaches below the liquefaction temperature (such as -20~-25℃), and obtain liquid carbon dioxide (such as Figure 2 Stream 106 in the flow).

[0060] In this embodiment, the first refrigeration unit is integrated into the system and compression is performed with the aid of the compressor of the compression unit for producing supercritical carbon dioxide, thereby liquefying the first stream to produce liquid carbon dioxide. This helps to reduce the power consumption of the compression unit and improve the flexibility of the system. At the same time, the number of compression units installed is reduced, thereby reducing investment costs and occupied area.

[0061] To reduce system energy consumption, in an exemplary embodiment, the second refrigeration unit 300 includes an expander and a second liquefier. The input end of the expander is connected to the interstage of the compression unit 100, and the second liquefier is connected to the input end of the compressor of the compression unit 100. The expander is used to expand part of the extracted supercritical carbon dioxide, recover the energy generated during the expansion process, and reduce the temperature of the extracted part of the supercritical carbon dioxide to provide cooling capacity for the second liquefier.

[0062] In practical applications, the expander can be a turbine expander or a throttling expansion valve. The connection between the expander and the second liquefier is as follows: Figure 2 As shown, the input end of the expander is connected to the output end of the compressor of the compression unit 100, and the second liquefier is connected to the input end of the compressor of the compression unit 100. In this embodiment, the second refrigeration unit expands the input supercritical carbon dioxide to produce cooling carbon dioxide 113, and returns the cooling carbon dioxide 113 to the compression unit. The expander can also expand (throttle) the extracted supercritical carbon dioxide. During this process, the pressure and temperature of the supercritical carbon dioxide drop rapidly, thereby generating cooling. The expander recovers a portion of the mechanical energy and supplies the generated cooling energy to the second liquefier.

[0063] In this embodiment, the supercritical carbon dioxide used for reflux is expanded to generate cold energy, which is beneficial for refrigeration and temperature reduction and reduces system energy consumption.

[0064] In an exemplary embodiment, the compression unit 100 includes a compressor, an interstage compressor, and a gearbox connected to each other.

[0065] In practical applications, the transmission can be a gear transmission, a hydraulic transmission, or an electronically controlled transmission. For example, a gear transmission can be configured to control the compression speed of different compressor stages by adjusting the gear combination based on the compressor's compression demand input via a controller (not shown). The gear combination changes the rotational ratio on the drive shaft, thereby controlling the compression speed of each compressor stage. The compression demand can be determined based on the output requirements of supercritical CO2 and liquid CO2. Therefore, during periods of high demand (e.g., to increase supercritical CO2 production), the gear ratio can be reduced to increase compressor speed, thereby increasing compressor output. Conversely, during periods of low demand, the speed can be reduced to conserve energy.

[0066] In this embodiment, by arranging a gearbox and an interstage cooler between each stage of the compressor, the compressor cooperates with the gear gearbox to perform decoupling and speed adjustment, which is conducive to flexible adjustment of the output flow of liquid carbon dioxide and supercritical carbon dioxide according to different needs.

[0067] In an exemplary embodiment, the compression unit 100 includes a multi-stage compressor, a plurality of interstage coolers and a plurality of gearboxes. The multi-stage compressors are connected in sequence through a plurality of drive shafts, and a gearbox and an interstage cooler are provided between each drive shaft and the main shaft of each stage of the compressor.

[0068] In actual applications, the compression unit is driven by a variable frequency motor, and a multi-axis connection method is used to transmit power to each stage of the compressor through the drive shaft that passes through each stage of the compressor and the gearbox. The gearbox and interstage cooler are set between each stage of the compressor. The drive shaft can be connected to the compressor and gearbox at each stage using a coupling to compensate for slight deviations between the shafts and transmit torque at the same time. The drive shaft is supported by bearings between each stage of the compressor and the gearbox to ensure stable rotation of the shaft and reduce friction and wear. Each stage of the compressor includes a compressor and a corresponding cooler. Figure 2 As shown, the gaseous carbon dioxide 101 of the gas source enters the first-stage compressor of the compression unit for preliminary compression and cooling, and then enters the next-stage compressor for further compression, and this process is repeated until the gaseous carbon dioxide reaches a supercritical state, thereby producing supercritical carbon dioxide 110.

[0069] In this embodiment, the system's multi-shaft connection of multi-stage compressors and the gearboxes between each stage facilitate adjusting the compressor speed according to compression requirements, improving the operating efficiency and reliability of the compressors and enhancing the system's adaptability to different application scenarios.

[0070] In an exemplary embodiment, the system further includes a first regulating valve and a second regulating valve, and the first stream includes a first split stream and a second split stream.

[0071] The first regulating valve is disposed between the compression unit 100 and the first liquefier, and is used to adjust the flow rate of the first branch flow.

[0072] The second regulating valve is provided between the compression unit 100 and the second liquefier, and is used for adjusting the flow rate of the second split flow.

[0073] The first sub-flow is the gaseous carbon dioxide injected into the first refrigeration unit, and the second sub-flow is the gaseous carbon dioxide injected into the second refrigeration unit.

[0074] In practical applications, in order to reduce the energy consumption of the first refrigeration unit, a second refrigeration unit is designed in the system. The first liquefier and the second liquefier can both be used to liquefy gaseous carbon dioxide to obtain liquid carbon dioxide. Figure 2As shown, during the first stream 102 flowing out of the compression unit, it is split into a first substream 104 and a second substream 107. The first substream 104 is injected into the first liquefier for liquefaction to obtain liquid carbon dioxide ( Figure 2 The first regulating valve is provided between the compression unit and the first liquefier, and is capable of adjusting the flow rate of the first split stream. The second split stream 107 is injected into the second liquefier and liquefied to obtain liquid carbon dioxide ( Figure 2 The stream 108 in the figure), the liquid carbon dioxide produced by the first refrigeration unit and the second refrigeration unit are combined and output (corresponding to the stream 109 in Figure 2). The second regulating valve is provided between the compression unit and the second liquefier, and can adjust the flow of the second branch. The first regulating valve and the second regulating valve can respectively adjust the flow of the first branch and the second branch under the condition of variable load regulation of the compressor. The first regulating valve and the second regulating valve can be electric regulating valves, self-operated regulating valves or intelligent regulating valves, etc. Taking the electric regulating valve as an example, when the downstream super-critical carbon dioxide demand changes, the first regulating valve and the second regulating valve can control the flow of the first branch to decrease according to the received electrical signal, and adjust the flow of the adjusted stream ( Figure 2 The stream 105 in the first liquefier is transmitted to the first liquefier, and the second regulating valve controls the flow of the second split stream to increase, so that the amount of carbon dioxide processed by the first refrigeration unit is reduced accordingly, thereby reducing the power.

[0075] In this embodiment, by providing a regulating valve, the flow rate of carbon dioxide can be adjusted according to actual needs, thereby improving the flexibility of the system and helping to reduce the energy consumption of the system.

[0076] In an exemplary embodiment, the first liquefier is configured to liquefy the first fraction to obtain liquid carbon dioxide.

[0077] The second liquefier is used to liquefy the second branch flow to obtain liquid carbon dioxide.

[0078] In actual application, following the steps of the above embodiment, when the demand for supercritical carbon dioxide in the downstream changes, the compressor is load-regulated, and the compression unit extracts part of the supercritical carbon dioxide and sends it to the second refrigeration unit. The pressure energy of this part of the supercritical carbon dioxide is converted into cold energy through the expander, and the cooling capacity is provided to the second liquefier (such as Figure 2 112 in the figure), the cooling carbon dioxide obtained after the expansion process in the expander flows through the second liquefier and flows back to the compression unit, so that the second liquefier uses the cooling capacity to liquefy the second split flow to obtain liquid carbon dioxide.

[0079] In this embodiment, the second refrigeration unit is provided and the second liquefier of the second refrigeration unit is used to help reduce the power consumption of the first refrigeration unit and improve the flexibility of the system.

[0080] In an exemplary embodiment, the system further includes a third regulating valve, which is disposed between the compression unit 100 and the expander and is configured to transfer a portion of the supercritical carbon dioxide to the expander of the second refrigeration unit 300 .

[0081] In practical applications, following the steps of the above embodiment, the third regulating valve can be an electric regulating valve, a self-operated regulating valve or an intelligent regulating valve. Taking the electric regulating valve as an example, when the demand for supercritical carbon dioxide in the downstream changes, the third regulating valve opens the valve according to the electrical signal sent by the controller, so that part of the supercritical carbon dioxide produced by the compression unit (such as Figure 2 The stream 111 in the refrigeration unit is injected into the expander of the second refrigeration unit, so that the expander expands / throttles and refrigerates part of the supercritical carbon dioxide.

[0082] In this embodiment, by providing a third regulating valve between the expander and the compression unit, it is advantageous to utilize the refluxed supercritical carbon dioxide for refrigeration and supply it to the second liquefier for liquefaction treatment, thereby reducing system energy consumption.

[0083] In an exemplary embodiment, Figure 3 As shown, the system also includes a controller 120, and the first refrigeration unit 200, the second refrigeration unit 300 and the compression unit 100 are respectively connected to the controller 120. The controller 120 is used to respond to the co-production control instruction, control the compression unit 100 to compress and cool the gaseous carbon dioxide, and divert the treated gaseous carbon dioxide to obtain a first stream and a second stream.

[0084] In actual applications, the operator may initiate a co-production control instruction in the controller, instructing the controller to control the first refrigeration unit, the second refrigeration unit and the compressor to coordinate the co-production of liquid carbon dioxide and supercritical carbon dioxide. Specifically, it may be according to the control process pre-set by the operator and stored in the controller, and the corresponding control operation is performed according to the control process. For example, the controller sends a compression control instruction to the compression unit, and the compression unit receives the compression control instruction, compresses and cools the gaseous carbon dioxide, and diverts the treated gaseous carbon dioxide to obtain a first stream and a second stream. In this embodiment, the method for the compression unit to process the gaseous carbon dioxide to obtain the first stream and the second stream refers to the steps of the compression unit compressing and cooling the gaseous carbon dioxide, diverting the treated gaseous carbon dioxide to obtain the first stream and the second stream, and transmitting the first stream to the first refrigeration unit in the above embodiment, which will not be repeated here.

[0085] The first refrigeration unit 200 is controlled to cool the first stream to obtain liquid carbon dioxide.

[0086] In actual applications, the controller sends a cooling control instruction to the first refrigeration unit. The first refrigeration unit receives the cooling control instruction and cools the first stream to obtain liquid carbon dioxide. The steps of cooling the first stream to obtain liquid carbon dioxide by the first refrigeration unit in the above embodiment are referred to and will not be repeated here.

[0087] The compression unit 100 is controlled to compress and cool the second stream to obtain supercritical carbon dioxide, and a portion of the supercritical carbon dioxide is extracted.

[0088] In actual application, the compression unit receives the compression control instruction, compresses and cools the second stream to obtain supercritical carbon dioxide, and extracts part of the supercritical carbon dioxide in the supercritical carbon dioxide. Referring to the above embodiment, the compression unit compresses and cools the second stream to obtain supercritical carbon dioxide, extracts part of the supercritical carbon dioxide in the supercritical carbon dioxide and transmits it to the second refrigeration unit, which will not be repeated here.

[0089] The second refrigeration unit 300 is controlled to expand part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and the cooling carbon dioxide is refluxed to the second stream.

[0090] In actual applications, the controller sends an expansion control instruction to the second refrigeration unit. The second refrigeration unit receives the expansion control instruction, expands part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and returns the cooling carbon dioxide to the second stream. Referring to the steps in the above embodiment, the second refrigeration unit expands the input supercritical carbon dioxide to obtain cooling carbon dioxide and returns the cooling carbon dioxide to the compression unit, which will not be repeated here.

[0091] In this embodiment, the controller coordinates and controls the compression unit, the first refrigeration unit, and the second refrigeration unit, which is beneficial to improving the co-production efficiency of liquid carbon dioxide and supercritical carbon dioxide.

[0092] Based on the same inventive concept, the present application also provides a method for co-producing liquid carbon dioxide and supercritical carbon dioxide, which can be applied to Figure 4 In the application environment shown, the controller 120 communicates with the liquid carbon dioxide and supercritical carbon dioxide cogeneration system via a network. The controller 120 can be, but is not limited to, various personal computers, laptops, smart phones, and tablet computers.

[0093] Specifically, the controller may control the compression unit to compress and cool the gaseous carbon dioxide, divert the treated gaseous carbon dioxide to obtain a first stream and a second stream, control the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide, control the second refrigeration unit to compress and cool the second stream to obtain supercritical carbon dioxide, extract part of the supercritical carbon dioxide, expand part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the second stream.

[0094] In an exemplary embodiment, Figure 5 As shown, a method for co-producing liquid carbon dioxide and supercritical carbon dioxide is provided, which is described by taking the method applied to the controller 120 in FIG4 as an example, and includes the following S100 to S400. Among them:

[0095] S100 , in response to a co-generation control instruction, controlling a compression unit to compress and cool the gaseous carbon dioxide, and splitting the treated gaseous carbon dioxide into a first stream and a second stream.

[0096] S200, controlling the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide.

[0097] S300, controlling the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extracting part of the supercritical carbon dioxide.

[0098] S400: Control the second refrigeration unit to expand part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the second stream.

[0099] The first stream is used to produce liquid carbon dioxide, while the second stream is used to produce supercritical carbon dioxide. Supercritical carbon dioxide refers to carbon dioxide that is above its critical temperature (31.1°C) and pressure (7.38 MPa). The carbon dioxide used for cooling is expanded carbon dioxide.

[0100] In practical applications, a controller coordinates the operation of the compression unit, the first refrigeration unit, and the second refrigeration unit to improve system efficiency. Specifically, an operator may initiate a cogeneration control command on the controller, instructing the controller to control the first refrigeration unit, the second refrigeration unit, and the compressor to coordinate the cogeneration of liquid carbon dioxide and supercritical carbon dioxide. The controller issues corresponding commands to each unit, and each unit responds to the received commands. Specifically, the steps for controlling the units to coordinate the cogeneration of liquid carbon dioxide and supercritical carbon dioxide by the controller are described in the above embodiment and will not be repeated here.

[0101] The above-mentioned method for co-producing liquid carbon dioxide and supercritical carbon dioxide, on the one hand, improves the flexibility of preparation by integrating the preparation of liquid carbon dioxide and supercritical carbon dioxide, which is conducive to reducing investment costs and occupied area; on the other hand, by expanding part of the produced supercritical carbon dioxide and recovering part of the mechanical energy through the expansion process, power consumption is reduced, which is conducive to optimizing the system preparation efficiency.

[0102] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0103] In an exemplary embodiment, Figure 6 As shown, a liquid carbon dioxide and supercritical carbon dioxide co-production device 600 is provided, including: a compression control module 610, a cooling control module 620, and an expansion control module 630, wherein:

[0104] Compression control module 610 is configured to control a compression unit to compress and cool the gaseous carbon dioxide, split the treated gaseous carbon dioxide into a first stream and a second stream, control the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extract a portion of the supercritical carbon dioxide from the supercritical carbon dioxide.

[0105] a cooling control module 620 for controlling the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide;

[0106] The expansion control module 630 is used to control the second refrigeration unit to expand part of the supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the second stream.

[0107] Each module in the aforementioned liquid carbon dioxide and supercritical carbon dioxide cogeneration device 600 may be implemented in whole or in part through software, hardware, or a combination thereof. Each module may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0108] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Figure 7 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected via a system bus, and the communication interface is connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for co-producing liquid carbon dioxide and supercritical carbon dioxide is implemented.

[0109] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0110] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of any one of the above-mentioned embodiments of the method for co-producing liquid carbon dioxide and supercritical carbon dioxide are implemented.

[0111] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the above-mentioned embodiments of the method for co-producing liquid carbon dioxide and supercritical carbon dioxide are implemented.

[0112] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the steps of any one of the above-mentioned embodiments of the method for co-producing liquid carbon dioxide and supercritical carbon dioxide.

[0113] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0114] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0115] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0116] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A system for co-producing liquid carbon dioxide and supercritical carbon dioxide, characterized in that: The system includes a compression unit, and a first refrigeration unit and a second refrigeration unit respectively connected to the compression unit. The compression unit is used to compress and cool the gaseous carbon dioxide, split the treated gaseous carbon dioxide into a first stream and a second stream, and transmit the first stream to the first refrigeration unit; The first refrigeration unit is used to cool the first stream to obtain liquid carbon dioxide; The compression unit is used to compress and cool the second stream to obtain supercritical carbon dioxide, and extract a portion of the supercritical carbon dioxide to transmit to the second refrigeration unit; The second refrigeration unit is used to expand the input supercritical carbon dioxide to obtain cooling carbon dioxide, and return the cooling carbon dioxide to the compression unit.

2. The system according to claim 1, wherein: The first refrigeration unit includes a first liquefier, and a gas-liquid separator, a refrigerant compressor, an oil separator, and a condenser connected to the first liquefier in sequence. The output end of the condenser is connected to the first liquefier, and the first liquefier is connected to the compression unit.

3. The system according to claim 1, wherein: The second refrigeration unit includes an expander and a second liquefier. The input end of the expander is connected to the output end of the compression unit, and the second liquefier is connected to the interstage of the compressor of the compression unit. The expander is used to expand the extracted part of the supercritical carbon dioxide, recover the energy generated during the expansion process, and reduce the temperature of the extracted part of the supercritical carbon dioxide to provide cooling capacity for the second liquefier.

4. The system according to claim 3, characterized in that The compression unit includes an interconnected compressor, an interstage cooler and a gearbox.

5. The system according to claim 4, characterized in that The compression unit includes a multi-stage compressor, a plurality of interstage coolers and a plurality of gearboxes. The plurality of compressors are connected in sequence through a plurality of drive shafts. A gearbox and an interstage cooler are provided between each drive shaft and the main shaft of each compressor.

6. The system according to claim 5, characterized in that The system further includes a first regulating valve and a second regulating valve, wherein the first stream includes a first split stream and a second split stream; The first regulating valve is provided between the compression unit and the first liquefier, and is used to adjust the flow rate of the first split flow; The second regulating valve is disposed between the compression unit and the second liquefier, and is used to adjust the flow rate of the second split flow.

7. The system according to claim 6, characterized in that The first liquefier is used to liquefy the first split flow to obtain liquid carbon dioxide; The second liquefier is used to liquefy the second sub-flow to obtain liquid carbon dioxide.

8. The system according to claim 7, characterized in that The system further includes a third regulating valve, which is disposed between the compression unit and the expander and is configured to transfer part of the supercritical carbon dioxide to the expander of the second refrigeration unit.

9. The system according to claim 8, characterized in that The system further includes a controller, the first refrigeration unit, the second refrigeration unit, and the compression unit being connected to the controller respectively, the controller being configured to control the compression units to compress and cool the gaseous carbon dioxide in response to a co-generation control instruction, and to split the treated gaseous carbon dioxide into a first stream and a second stream; controlling the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide; controlling the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extracting a portion of the supercritical carbon dioxide; The second refrigeration unit is controlled to perform expansion processing on the portion of the supercritical carbon dioxide to obtain cooling carbon dioxide, and the cooling carbon dioxide is refluxed to the second stream.

10. A method for co-producing liquid carbon dioxide and supercritical carbon dioxide, characterized in that: Applied to the liquid carbon dioxide and supercritical carbon dioxide co-production system according to any one of claims 1 to 9, the method comprises: In response to the co-generation control instruction, controlling the compression unit to compress and cool the gaseous carbon dioxide, and splitting the treated gaseous carbon dioxide into a first stream and a second stream; controlling the first refrigeration unit to cool the first stream to obtain liquid carbon dioxide; controlling the compression unit to compress and cool the second stream to obtain supercritical carbon dioxide, and extracting a portion of the supercritical carbon dioxide; The second refrigeration unit is controlled to perform expansion processing on the portion of the supercritical carbon dioxide to obtain cooling carbon dioxide, and the cooling carbon dioxide is refluxed to the second stream.

Images