Apparatus and method for providing carbon dioxide
By designing a device including a separation device, a preheater and a multi-stage compressor, the heat energy of carbon dioxide (CO2) is used to generate steam by using a steam generator, and the pressure and temperature of carbon dioxide (CO2) is increased step by step by step by step by step by step by solving the problems of high energy consumption and high cost in the separation and compression of carbon dioxide (CO2) in the prior art, and achieving efficient heat utilization and heat recovery.
Patent Information
- Application Number
- CN202380067741.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-22
- Filing Date
- 2023-09-05
- Publication Date
- 2025-04-29
AI Technical Summary
The prior art has problems of high energy consumption and high cost in the separation and compression of carbon dioxide (CO2), especially when heat utilization is insufficient.
By designing a device including a separation device, a preheater and a multi-stage compressor, the heat energy of carbon dioxide (CO2) is used to generate steam using a steam generator, and the pressure and temperature of carbon dioxide (CO2) are increased step by step by step through the multi-stage compressor to maximize the use of heat.
The efficient recycling and utilization of carbon dioxide (CO2) compressed heat is achieved, which maximizes the heat recovery effect of low-pressure steam treatment, reduces energy consumption and costs, and reduces the demand for additional facilities and space.
Smart Images
Figure CN119907711A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a device and a method for operating a device.
[0002] The present invention particularly relates to an apparatus and method for separating and treating carbon dioxide (CO2) for transport in pipelines. Background Art
[0003] It is well known that there is a need to reduce carbon dioxide (CO2) emissions from power plants and other process operations. Here, carbon separation is considered an important factor in achieving the global goal of reducing CO2 emissions to the lowest possible level.
[0004] The International Energy Agency (IEA) predicts that in order to achieve climate goals, the amount of CO2 separated may increase from the current 50 million tons per year to 7.6 billion tons per year by 2050.
[0005] To separate carbon dioxide (CO2) from waste gases such as flue gas, the only technology currently available for commercial use on a large scale is the amine system. Amine systems require large amounts of low-pressure steam and, therefore, heat for the process, which is quite expensive, making carbon separation generally economically unattractive for operators.
[0006] Another aspect is that CO2 usually has to be transported long distances after storage if there are no storage or recovery facilities nearby. For this purpose, pipeline transportation in the supercritical phase is generally considered a good method. In order to bring CO2 into the supercritical phase, it must be compressed from near atmospheric pressure to supercritical pressure (more than 73 bar and 31 ° C), usually between 100 and 200 bar.
[0007] During the compression process, a large amount of heat is released, but this heat is currently not utilized due to the low temperature levels.
[0008] Depending on how the amine system is used, there are different potential heat sources. Some processes are exothermic, so the waste heat stream can be used for LP steam processing. But if this is not the case, and there is no alternative heat source, a fuel or electrically heated boiler must be installed. Natural gas boilers are often used, which consume large amounts of natural gas and also produce additional carbon dioxide (CO2), which also has to be separated, resulting in higher energy and investment requirements for the amine system.
[0009] For the heat of compression, it is important to use it rationally and to combine it as much as possible with the ND steam treatment required for the amine plant. However, low-quality heat must first be converted into high-quality heat. One possible approach is to use fewer intercoolers between the compression stages so that the carbon dioxide (CO2) is only cooled when the temperature is higher than that which can be used for ND steam treatment. However, the carbon dioxide (CO2) is then cooled back to atmospheric temperature, so that the amount of steam that can be generated is relatively small and the heat is only partially utilized. If the heat is to be utilized 100% and the steam production is maximized, a high-temperature heat pump can be used. However, this will result in significantly higher investment costs and space requirements. Summary of the invention
[0010] Against this background, it is an object of the present invention to provide a device and a method for providing carbon dioxide (CO 2 ) in a cost-optimized manner.
[0011] Another object of the present invention is to maximize heat recovery from low pressure (LP) steam processing at the lowest possible cost and space requirements.
[0012] The object is achieved by a device for providing carbon dioxide (CO2), the device comprising a separation device, wherein the separation device is connected to a gas mixture consisting of flue gas and carbon dioxide (CO2) by flow technology, wherein the separation device is configured to separate the carbon dioxide (CO2) contained in the flue gas, wherein during operation, the separation device can be operated using steam from a steam pipeline, the device also comprising: a first carbon dioxide pipeline, which is connected to the separation device by flow technology, and during operation, the carbon dioxide (CO2) separated in the separation device flows out of the first carbon dioxide pipeline; a preheater, through which the carbon dioxide pipeline passes, the preheater being configured to increase the temperature of the carbon dioxide (CO2); and a multi-stage compressor, the compressor On the inlet side, it is connected to the carbon dioxide pipeline from the preheater by flow technology, wherein, after a stage, the temperature and pressure of the carbon dioxide (CO2) increase, wherein, after the stage, the carbon dioxide (CO2) passes through a steam generator via a pipeline, wherein the steam generator is constructed so that water supplied to the steam generator generates steam by energy exchange with the heat energy of the carbon dioxide (CO2) that has passed through a stage from the compressor, wherein the carbon dioxide (CO2) cooled in the steam generator is returned to the next stage in the compressor, wherein the steam generated in the steam generator is connected to the separation device by flow technology via a steam pipeline, wherein the carbon dioxide (CO2) flowing out of the compressor after the last stage flows through the preheater and is heated and flows into the outlet pipeline.
[0013] The purpose of the method is achieved by the following steps:
[0014] - a gas mixture consisting of flue gas and carbon dioxide (CO2) is fed into the separation device by flow technology,
[0015] - separation of carbon dioxide (CO2) in a separation unit,
[0016] - supplying carbon dioxide (CO2) to a preheater, wherein the carbon dioxide (CO2) is heated in the preheater,
[0017] - conveying the carbon dioxide (CO 2 ) heated in the preheater to the first stage of the multi-stage compressor, wherein the pressure and temperature of the carbon dioxide (CO 2 ) are increased in the first stage,
[0018] - conveying the first stage heated carbon dioxide (CO 2 ) to a steam generator, wherein the thermal energy of the carbon dioxide (CO 2 ) is used to generate steam in the steam generator,
[0019] - performing a recycling step, wherein in the recycling step the carbon dioxide (CO 2 ) cooled in the steam generator is fed to the next stage of the compressor, wherein the temperature and pressure of the carbon dioxide (CO 2 ) are increased in the next stage,
[0020] - conveying the carbon dioxide (CO2) after the next stage of heating to a steam generator, wherein the thermal energy of the carbon dioxide (CO2) is used to generate steam in the steam generator,
[0021] - Repeat the recycling steps until the last stage,
[0022] - passing the CO2 flowing out after the last stage through a preheater,
[0023] - conveying the carbon dioxide flowing out of the preheater to the outlet pipeline,
[0024] In this case, the steam generated in the steam generator is connected to the separation device via a steam line in a fluidic manner.
[0025] The new solution makes it possible to maximize heat utilization and produce the same amount of steam as a heat pump, while requiring almost no additional facilities or extra space.
[0026] A key feature of the present invention is the compressor, which typically includes six to eight stages for compression from atmospheric pressure to supercritical pressure. This means that the process of compression and steam treatment in the waste heat boiler (HRSG) actually occurs multiple times, depending on the final number of stages required to reach the outlet pressure.
[0027] Regardless of the number of stages, the preheater and all other downstream components are used only once.
[0028] According to the invention, the CO2 is only cooled to such an extent that the heat is still available for steam processing in the waste heat boiler. This temperature is usually 5-10°C higher than the final steam temperature required for the amine system, but this depends on the final configuration of the heat exchanger. However, this means that the CO2 is not cooled back to atmospheric temperature before reaching the next compressor stage. This allows the steam processing after each compression stage to use the same number of heat exchangers / HRSGs as in conventional operation.
[0029] But in practice, this process can only start after the second or even the third compressor stage, because the CO2 must first be heated from the atmospheric outlet temperature after the amine system to a usable temperature level. To further maximize the steam treatment, the high temperature of the CO2 after the last HRSG can now be used to preheat the CO2 at the compressor inlet to a usable temperature level, so that the entire compressor (from inlet to outlet) operates at a temperature level that can handle steam, so that steam treatment can already start after the first compressor stage.
[0030] Although the CO2 after the preheater has been partially cooled in order to preheat the CO2 at the inlet, an aftercooler is required downstream of the preheater to cool the CO2 back to atmospheric temperature. In addition, the CO2 stream is usually dehydrated for pipeline injection, which is usually done using a triethylene glycol (TEG) system at a pressure of 40-50 bar, as this is the most economical way to dehydrate CO2. However, this means that the CO2 must be cooled to atmospheric temperature at 40-50 bar for dehydration.
[0031] This problem is solved by using a glycerol-based dehydration system, which, although somewhat expensive and energy-intensive, allows the dehydration of CO2 at supercritical pressure, thus maximizing steam production. However, if this is not desired for some reason, it is also possible to dehydrate CO2 using a TEG system at 40-50 bar. In this case, the preheater and heat exchanger need to be adapted.
[0032] According to the invention, no additional facilities or machinery are required and the additional space requirement is very limited, whereas a heat pump would increase the space requirement and investment costs by approximately one-fold. The solution thus significantly reduces the energy requirement of the amine system, thereby saving fuel, including carbon dioxide (CO2) when using fossil fuels, and therefore, in this case, also saving capital expenditure (CAPEX) of the amine system, since less carbon dioxide (CO2) needs to be separated, while no additional machinery is required, only some additional drive power.
[0033] Furthermore, since there is always feed water or CO2 from the inlet for cooling the CO2 in addition to the aftercooler, the compressor’s need for cooling water is also significantly reduced, which is also a significant advantage since in some regions the availability of cooling water is an issue.
[0034] Advantageous developments are specified in the dependent claims.
[0035] An advantage of the present invention is that it maximizes the thermal utilization and recovery of the heat of compression of carbon dioxide (CO2) with little additional machinery and space requirements.
[0036] Another advantage is the saving of fuel in the boiler for the ND steam treatment of the amine system.
[0037] A particular advantage is the significant saving in cooling water for the CO2 compressor.
[0038] Another advantage is that potential savings in carbon dioxide (CO2) are achieved when using fossil fuels as the heat source for the boiler.
[0039] The above characteristics, features and advantages of the present invention and the ways of implementing them will become clearer and easier to understand with the following description of the embodiments, which will be explained in more detail with the accompanying drawings.
[0040] Identical components or components having the same function are identified here by the same reference numerals. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] Embodiments of the present invention are described below in conjunction with the accompanying drawings. These drawings are not intended to show the embodiments to scale; rather, the drawings are presented in schematic and / or slightly distorted form when explanation is required. For supplements to the teachings directly visible in the drawings, please refer to the relevant prior art.
[0042] in:
[0043] Figure 1 A schematic diagram showing an embodiment of the device according to the invention; and
[0044] Figure 2 A schematic diagram shows an alternative embodiment of the device according to the invention. DETAILED DESCRIPTION
[0045] Figure 1 A schematic diagram of an embodiment of a device 1 according to the invention is shown.
[0046] The device 1 is used to provide carbon dioxide (CO2) and comprises a separation device 2. The separation device 2 is connected to a gas mixture 4 consisting of flue gas and carbon dioxide (CO2) by flow technology via a pipeline 3. The separation device 2 is designed so that it separates the carbon dioxide (CO2) contained in the flue gas 4. The separated carbon dioxide (CO2) flows from the separation device 2 via a first carbon dioxide pipeline 5 through a preheater 6. In the preheater 6, the temperature of the carbon dioxide (CO2) is increased.
[0047] The first carbon dioxide line 5 is connected to the separation device 2 via flow technology. The separation device 2 is designed here as an amine device.
[0048] In operation, the separation device 2 is operated with steam from the steam line 7. Carbon dioxide (CO2) produced in the boiler 8 is also optionally fed to the separation device 2 via the line 10. Steam produced in the boiler 8 is conducted to the separation device 2 via the line 11.
[0049] The carbon dioxide (CO2) heated by the preheater 6 is fed to the multi-stage compressor 13 via the pipeline 12. The multi-stage compressor 13 is connected to the carbon dioxide pipeline 5 from the preheater 6 on the inlet side by flow technology.
[0050] In the compressor 13 , the heated carbon dioxide (CO 2 ) is fed into the first stage, wherein the temperature and the pressure of the carbon dioxide are increased in the first stage.
[0051] After the first stage, carbon dioxide (CO2) is supplied to a steam generator 15, which may be configured as a HRSG (Heat Recovery Steam Generator) through a pipeline 14. The steam generator 15 is configured so that the water supplied to the steam generator 15 is converted into steam by exchanging energy with the heat energy of carbon dioxide (CO2) that has passed through one stage from the compressor 13.
[0052] The compressor 13 has five to ten stages, in particular six to nine stages, most particularly seven stages or eight stages.
[0053] The carbon dioxide (CO2) cooled in the steam generator 15 is returned to the compressor 13 via the pipeline 16 in order to enter the next stage. There, the carbon dioxide (CO2) is fed to the next stage and from there to the steam generator 15. This happens multiple times, i.e. through multiple stages in the compressor 13, wherein after each stage, the heat energy of the carbon dioxide (CO2) is used to generate steam in the steam generator 15. For the sake of clarity, Figure 1Only one line 14 leading to the steam generator 15 and one line 16 leading from the steam generator 15 to the compressor 13 are shown. For the sake of clarity, each line leading to the steam generator 15 and back to the compressor 13 is not shown.
[0054] The steam generated in the steam generator 15 is connected to the separation device 2 via a steam line 7 in terms of flow technology.
[0055] Carbon dioxide (CO 2 ) flowing out from the compressor 13 after the last stage flows through the preheater 6 via the pipeline 17 .
[0056] Then, the carbon dioxide (CO 2 ) flows into the aftercooler 18 , wherein the aftercooler 18 is configured to reduce the temperature of the carbon dioxide (CO 2 ) from the preheater 6 . The aftercooler 18 is supplied with cooling water 20 .
[0057] Downstream of the aftercooler 18, the carbon dioxide (CO2) flows through a dehydration unit (glycerol) 19, wherein the dehydration unit 19 is configured to dehydrate the carbon dioxide (CO2) from the preheater 6. Here, the water separated in the dehydration unit 19 is discharged through a dehydration line 21.
[0058] The aftercooler 18 is fluidically connected to the cooling water via a cooling water line 20 .
[0059] The carbon dioxide (CO2) produced and provided in the plant 1 is subsequently processed for transport in a pipeline.
[0060] Figure 2 A schematic diagram of an alternative embodiment of an apparatus 1 for providing carbon dioxide (CO2) according to the invention is shown. The separation process in the separation device 2 by means of a compressor 13 is similar to the separation process according to Figure 1 Therefore, please refer to Figure 1 of the above description.
[0061] According to Figure 1 The difference of the device is that, for example, a further compressor 22 is arranged between the preheater 6 and the aftercooler 28, which is connected downstream of the superheater 23 by means of flow technology. The superheater 23 is in turn connected by flow technology to a dehydration device 24, which can be designed as a TEG system. The separated water 25 flows out of the dehydration device 24.
[0062] Between the preheater 6 and the dewatering device 24 there is a cooler 26 which is supplied with water 27 .
[0063] The further compressor 22 is connected to the steam generator 31 by flow technology in a similar manner to the compressor 13. As described for the compressor 13, in the further compressor 22, carbon dioxide (CO2) is fed to the steam generator 31 after each stage.
[0064] The carbon dioxide (CO2) cooled in the steam generator 31 is returned to the other compressor 22 via the pipeline 32 in order to enter the next stage of the other compressor 22. There, the carbon dioxide (CO2) is fed to the next stage and from there to the steam generator 31. This happens multiple times, i.e., through multiple stages in the other compressor 22, wherein, after each stage, the heat energy of the carbon dioxide (CO2) is used to generate steam in the steam generator 31. For the sake of clarity, Figure 2 Only one line 33 leading to the steam generator 31 and one line 32 from the steam generator 31 to the compressor 22 are shown. For the sake of clarity, each line leading to the steam generator 31 and returning to the other compressor 22 is not shown.
[0065] The steam generated in the steam generator 31 is connected fluidically to the steam line 7 via a steam line 34 and is therefore connected fluidically to the separation device 2 via the steam line 34 .
[0066] Carbon dioxide (CO 2 ) flowing out from the other compressor 22 through the last stage flows through a superheater 23 through a pipeline.
[0067] The steam generator 31 is fluidically connected to the line 9 via the line 35 .
[0068] Downstream of the superheater 23 there is arranged an aftercooler 28 which is likewise supplied with water 29 as a cooling medium. The carbon dioxide (CO 2 ) produced and provided in the plant 1 is subsequently processed for transport in a pipeline 30 .
Claims
1. A device (1) for providing carbon dioxide (CO2), comprising a separation device (2), wherein: The separation device (2) is connected to a gas mixture (4) consisting of flue gas and carbon dioxide (CO2) via flow technology, wherein the separation device (2) is designed to separate the carbon dioxide (CO2) contained in the flue gas. wherein, during operation, the separation device (2) can be operated using steam from a steam line (7), The device also includes: a first carbon dioxide pipeline (5), the first carbon dioxide pipeline being connected to the separation device (2) by flow technology, and during operation, the carbon dioxide (CO2) separated in the separation device (2) flows out of the first carbon dioxide pipeline; a preheater (6) through which the carbon dioxide line (5) passes, the preheater being configured to increase the temperature of the carbon dioxide (CO2); and a multi-stage compressor (13) which is fluidically connected on the inlet side to the carbon dioxide line (12) coming from the preheater (6), wherein, after one stage, the temperature and pressure of the carbon dioxide (CO2) are increased, wherein, after the stage, the carbon dioxide (CO2) passes through a steam generator (15) via a pipeline (14), wherein the steam generator (15) is configured such that water supplied to the steam generator (15) generates steam by exchanging energy with the heat energy of the carbon dioxide (CO2) that has passed through one stage from the compressor (13), wherein the carbon dioxide cooled in the steam generator (15) is returned to the next stage in the compressor (13), The steam generated in the steam generator (15) is connected to the separation device (2) via the steam pipeline (7) by means of flow technology. The carbon dioxide (CO2) flowing out from the compressor (13) after the last stage flows through the preheater (6) and is heated and flows into the outlet pipeline.
2. The device (1) according to claim 1, in, The carbon dioxide (CO2) produced in the plant (1) is processed for transport in a pipeline.
3. The device (1) according to claim 1 or 2, in, The separation device (2) is designed as an amine device.
4. The device (1) according to claim 1, 2 or 3, in, The compressor (13) has five to ten stages, in particular six to nine stages, most particularly seven or eight stages.
5. The device (1) according to any one of the preceding claims, wherein: An aftercooler (18) is arranged downstream of the preheater (6), wherein the aftercooler (18) is configured to reduce the temperature of the carbon dioxide (CO2) coming from the preheater (6).
6. The device (1) according to any one of the preceding claims, wherein: A dehydration unit (19) is arranged downstream of the preheater (6), wherein the dehydration unit (19) is configured to dehydrate carbon dioxide (CO2) from the preheater (6).
7. The device (1) according to claim 6, in, The dehydration unit (19) is arranged downstream of the aftercooler (18).
8. The device (1) according to any one of claims 1 to 5, A further compressor (22) is arranged between the compressor (13) and the preheater (6), wherein: The compressor (13) and the further compressor (22) are fluidically connected to one another.
9. The device (1) according to claim 8, in, A cooler (26) is arranged between the compressor (13) and the further compressor (22), wherein the outlet of the compressor (13) is connected to the inlet of the cooler (26) via flow technology, wherein the outlet of the cooler (26) is connected to the inlet of the further compressor (22) via flow technology.
10. The device (1) according to claim 9, in, A dehydration device (24) is arranged between the cooler (26) and the further compressor (22), wherein the outlet of the cooler (26) is connected to the inlet of the dehydration device (24), wherein the outlet of the dehydration device (24) is connected to the inlet of the further compressor (22) via flow technology.
11. The device (1) according to claim 10, The dehydration device is configured as a triethylene glycol (TEG) system.
12. A method for providing carbon dioxide (CO2), The method comprises the following steps: - feeding a gas mixture consisting of flue gas and carbon dioxide (CO2) into a separation device (2) by means of flow technology, - separation of carbon dioxide (CO2) in the separation device (2), - feeding the carbon dioxide (CO2) to a preheater (6), wherein The carbon dioxide (CO2) is heated in the preheater (6), - conveying the carbon dioxide (CO 2 ) heated in the preheater ( 6 ) to the first stage of a multi-stage compressor ( 13 ), wherein the pressure and temperature of the carbon dioxide (CO 2 ) are increased in the first stage, - conveying the heated carbon dioxide (CO 2 ) that has passed through the first stage to a steam generator ( 15 ), wherein the thermal energy of the carbon dioxide (CO 2 ) is utilized to generate steam in the steam generator ( 15 ), - performing a recycling step, wherein in the recycling step the carbon dioxide (CO2) cooled in the steam generator (15) is directed to the next stage of the compressor (13), wherein the temperature and pressure of the carbon dioxide (CO2) are increased in the next stage, - conveying the heated carbon dioxide (CO 2 ) that has passed through the next stage to the steam generator (15), wherein the thermal energy of the carbon dioxide (CO 2 ) is utilized to generate steam in the steam generator (15), - repeating the recycling steps until the last stage, - passing the carbon dioxide (CO2) flowing out after the last stage through the preheater (6), - conveying the carbon dioxide (CO2) flowing out of the preheater (6) to an outlet pipeline, - wherein the steam generated in the steam generator (15) is connected to the separation device (2) via the steam line (7) in a flow-technical manner.
13. The method according to claim 12, in, An aftercooler (18) is arranged downstream of the preheater (6), wherein the aftercooler (18) is configured to cool carbon dioxide (CO2) flowing out of the preheater (6).
14. The method according to claim 13, in, A dehydration unit (19) is arranged downstream of the aftercooler (18).
15. The method according to claim 12, A further compressor (22) is arranged between the compressor (13) and the preheater (6).
16. The method according to claim 15, in, A cooler (26) is arranged between the compressor (13) and the further compressor (22).
17. The method according to claim 16, in, A dehydration unit is arranged between the cooler (26) and the superheater (23).
18. The method according to claim 17, in, The dehydration unit is configured as a triethylene glycol (TEG) system.