A flue gas carbon dioxide treatment system and a flue gas carbon dioxide purification method

Abstract

The application discloses a system for treating carbon dioxide in flue gas and a method for purifying carbon dioxide in flue gas. The system comprises a flue gas drying device, a heat exchanger, a first compression device and a first gas-liquid separation device for liquefying and gas-liquid separating carbon dioxide. The inlet of the flue gas drying device is a flue gas inlet, the outlet of the flue gas drying device is connected with a first fluid inlet of the heat exchanger, a first fluid outlet of the heat exchanger is connected with an inlet of the first gas-liquid separation device, a liquid outlet of the first gas-liquid separation device is connected with a second fluid inlet of the heat exchanger, a second fluid outlet of the heat exchanger is connected with a first inlet of the first compression device, a gas outlet of the first gas-liquid separation device is connected with a third fluid inlet of the heat exchanger, and a third fluid outlet of the heat exchanger is a gas outlet. The application effectively saves energy by recycling heat.

Description

TECHNICAL FIELD

[0001] The present application relates to the chemical technology field, more particularly, to a flue gas carbon dioxide treatment system and a flue gas carbon dioxide purification method. BACKGROUND

[0002] Carbon dioxide is a common gas in the atmosphere, which plays a crucial role in people's lives.

[0003] However, the common carbon dioxide treatment method, such as chemical absorption method, realizes the absorption of carbon dioxide by chemical reaction between chemical solvent and carbon dioxide, but the current carbon dioxide treatment method has the disadvantage of high energy consumption. SUMMARY

[0004] Therefore, the present application provides a flue gas carbon dioxide treatment system and a flue gas carbon dioxide purification method to solve the problem of high energy consumption of the carbon dioxide treatment method.

[0005] In order to achieve the above purpose, the present scheme is as follows:

[0006] In a first aspect, the present application provides a flue gas carbon dioxide treatment system, which comprises: a flue gas drying device, a heat exchanger, a first compression device and a first gas-liquid separation device for liquefying and gas-liquid separating carbon dioxide;

[0007] The inlet of the flue gas drying device is a flue gas inlet, the outlet of the flue gas drying device is connected with the first fluid inlet of the heat exchanger, the first fluid outlet of the heat exchanger is connected with the inlet of the first gas-liquid separation device, the liquid outlet of the first gas-liquid separation device is connected with the second fluid inlet of the heat exchanger, and the second fluid outlet of the heat exchanger is connected with the first inlet of the first compression device;

[0008] The gas outlet of the first gas-liquid separation device is connected with the third fluid inlet of the heat exchanger, and the third fluid outlet of the heat exchanger is a gas outlet.

[0009] The first fluid inlet and the first fluid outlet are in communication, the second fluid inlet and the second fluid outlet are in communication, and the third fluid inlet and the third fluid outlet are in communication.

[0010] In an implementation manner of the first aspect, the flue gas carbon dioxide treatment system further comprises a second gas-liquid separation device for liquefying and gas-liquid separating carbon dioxide.

[0011] The third fluid outlet is connected with an inlet of the second gas-liquid separation device, a liquid outlet of the second gas-liquid separation device is connected with a fourth fluid inlet of the heat exchanger, and a fourth fluid outlet of the heat exchanger is connected with a second inlet of the first compression device;

[0012] A gas outlet of the second gas-liquid separation device is connected with a fifth fluid inlet of the heat exchanger, and a fifth fluid outlet of the heat exchanger is a gas outlet;

[0013] The fourth fluid inlet is in communication with the fourth fluid outlet, and the fifth fluid inlet is in communication with the fifth fluid outlet.

[0014] In an implementation form of the first aspect, the heat exchanger comprises: a first heat exchanger and a second heat exchanger;

[0015] An outlet of the flue gas drying device is connected with a first fluid inlet of the heat exchanger, a first fluid outlet of the heat exchanger is connected with an inlet of the first gas-liquid separation device, a liquid outlet of the first gas-liquid separation device is connected with a second fluid inlet of the heat exchanger, and a second fluid outlet of the heat exchanger is connected with a first inlet of the first compression device, and specifically configured as:

[0016] An outlet of the flue gas drying device is connected with a first fluid inlet of the first heat exchanger, a first fluid outlet of the first heat exchanger is connected with an inlet of the first gas-liquid separation device, a liquid outlet of the first gas-liquid separation device is connected with a second fluid inlet of the first heat exchanger, and a second fluid outlet of the first heat exchanger is connected with a first inlet of the first compression device;

[0017] A gas outlet of the first gas-liquid separation device is connected with a third fluid inlet of the heat exchanger, and a third fluid outlet of the heat exchanger is a gas outlet, and specifically configured as:

[0018] A gas outlet of the first gas-liquid separation device is connected with a third fluid inlet of the second heat exchanger, and a third fluid outlet of the second heat exchanger is a gas outlet;

[0019] A liquid outlet of the second gas-liquid separation device is connected with a fourth fluid inlet of the heat exchanger, and a fourth fluid outlet of the heat exchanger is connected with a second inlet of the first compression device, and specifically configured as:

[0020] A liquid outlet of the second gas-liquid separation device is connected with a fourth fluid inlet of the second heat exchanger, and a fourth fluid outlet of the second heat exchanger is connected with a second inlet of the first compression device;

[0021] The gas outlet of the second gas-liquid separation device is connected with the fifth fluid inlet of the heat exchanger, and the fifth fluid outlet of the heat exchanger is a gas outlet.

[0022] The gas outlet of the second gas-liquid separation device is connected with the fifth fluid inlet of the second heat exchanger, and the fifth fluid outlet of the second heat exchanger is a gas outlet.

[0023] In an implementation form of the first aspect, the carbon dioxide treatment system further comprises a second compression device,

[0024] The fourth fluid outlet is connected with the second inlet of the first compression device, and is specifically configured as:

[0025] The fourth fluid outlet is connected with the second inlet of the first compression device through the second compression device.

[0026] In an implementation form of the first aspect, the carbon dioxide treatment system further comprises a cooler;

[0027] The fourth fluid outlet is connected with the second inlet of the first compression device, and is specifically configured as:

[0028] The fourth fluid outlet is connected with the second inlet of the first compression device through the cooler.

[0029] In an implementation form of the first aspect, the carbon dioxide treatment system further comprises a cooler;

[0030] The fourth fluid outlet is connected with the second inlet of the first compression device, and is specifically configured as:

[0031] The fourth fluid outlet is connected with the second inlet of the first compression device through the second compression device and the cooler.

[0032] In an implementation form of the first aspect, the gas temperature of the gas outlet of the first gas-liquid separation device is-50 to-55℃;

[0033] and / or,

[0034] The gas pressure of the gas outlet of the first compression device is 11 MPa.

[0035] In an implementation form of the first aspect, the first heat exchanger and the second heat exchanger are the same heat exchanger or different heat exchangers.

[0036] In a second aspect, the present application provides a carbon dioxide purification method in flue gas, which is applied to the carbon dioxide treatment system in flue gas of the first aspect, and the method comprises:

[0037] drying the flue gas containing carbon dioxide in the flue gas drying device;

[0038] heat-exchanging the flue gas containing carbon dioxide after drying in the heat exchanger;

[0039] cooling and decompressing the flue gas containing carbon dioxide after heat-exchanging in the first gas-liquid separation device to obtain first liquid carbon dioxide and first gas;

[0040] heat-exchanging the first liquid carbon dioxide in the heat exchanger to vaporize the first liquid carbon dioxide into first gaseous carbon dioxide;

[0041] compressing the first gaseous carbon dioxide in the first compression device;

[0042] heat-exchanging the first gas in the heat exchanger to discharge the first gas after heat-exchanging.

[0043] In an implementation form of the second aspect, in the case that the carbon dioxide treatment system in the flue gas further comprises a second gas-liquid separation device for liquefying and gas-liquid separating carbon dioxide, the method further comprises:

[0044] cooling and decompressing the first gas discharged in the second gas-liquid separation device to obtain second liquid carbon dioxide and second gas;

[0045] heat-exchanging the second liquid carbon dioxide in the heat exchanger to vaporize the second liquid carbon dioxide into second gaseous carbon dioxide;

[0046] compressing the second gaseous carbon dioxide in the first compression device;

[0047] heat-exchanging the second gas in the heat exchanger to discharge the second gas after heat-exchanging.

[0048] The application dries the flue gas containing carbon dioxide through a flue gas drying device, the dried flue gas enters a heat exchanger for heat exchange treatment, the flue gas is cooled again in a first gas-liquid separation device, the flue gas is separated into first liquid carbon dioxide and first gas, the first liquid carbon dioxide and the first gas are subjected to heat exchange treatment through the heat exchanger, the first liquid carbon dioxide is vaporized into first gaseous carbon dioxide after heat exchange treatment, and the first gaseous carbon dioxide is put into a first compression device for compression and discharge of the first gas. The flue gas is subjected to heat exchange treatment in the heat exchanger first, thereby reducing the heat required for cooling the flue gas in the first gas-liquid separation device, and the first liquid carbon dioxide and the first gas are subjected to heat exchange treatment in the heat exchanger, the heat saved when the flue gas is subjected to heat exchange in the heat exchanger is used, no additional heat is used to vaporize the first liquid carbon dioxide, and no additional heat is used to heat the first gas, thereby realizing heat recycling and effectively saving energy. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the provided drawings.

[0050] Figure 1 A structure diagram of a carbon dioxide treatment system in flue gas is provided for the embodiments of the present application.

[0051] Figure 2 A flow direction diagram of fluid in the carbon dioxide treatment system in flue gas is provided for the embodiments of the present application.

[0052] Figure 3 A structure diagram of a carbon dioxide treatment system in flue gas is provided for the embodiments of the present application.

[0053] Figure 4 A flow direction diagram of fluid in the carbon dioxide treatment system in flue gas is provided for the embodiments of the present application.

[0054] Figure 5 A structure diagram of a carbon dioxide treatment system in flue gas is provided for the embodiments of the present application.

[0055] Figure 6 A flow direction diagram of fluid in the carbon dioxide treatment system in flue gas is provided for the embodiments of the present application.

[0056] Figure 7This is a schematic diagram of a carbon dioxide treatment system for flue gas provided in an embodiment of this application;

[0057] Figure 8 This is a schematic diagram of a carbon dioxide treatment system for flue gas provided in an embodiment of this application;

[0058] Figure 9 This is a schematic diagram of a carbon dioxide treatment system for flue gas provided in an embodiment of this application;

[0059] Figure 10 This is a schematic diagram of a carbon dioxide treatment system for flue gas provided in an embodiment of this application;

[0060] Figure 11 This is a schematic diagram of a carbon dioxide treatment system for flue gas provided in an embodiment of this application;

[0061] Figure 12 This is a schematic diagram of a carbon dioxide treatment system for flue gas provided in an embodiment of this application;

[0062] Figure 13 A flowchart of a method for purifying carbon dioxide from flue gas, provided as an embodiment of this application;

[0063] Figure 14 A flowchart of another method for purifying carbon dioxide from flue gas, provided as an embodiment of this application.

[0064] Legend: Flue gas drying equipment 1, heat exchanger 2, first heat exchanger 3, first gas-liquid separator 4, first compression device 5, second heat exchanger 6, second gas-liquid separator 7, second compression device 8, and cooler 9. Detailed Implementation

[0065] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] like Figure 1 and Figure 2 As shown in the embodiment of this application, a carbon dioxide treatment system in flue gas is provided. The carbon dioxide treatment system in flue gas includes: flue gas drying equipment 1, heat exchanger 2, first compression device 5, and first gas-liquid separation device 4 for liquefying carbon dioxide and performing gas-liquid separation.

[0067] The inlet of the flue gas drying device 1 is a flue gas inlet, the outlet of the flue gas drying device 1 is connected with the first fluid inlet of the heat exchanger 2, the first fluid outlet of the heat exchanger 2 is connected with the inlet of the first gas-liquid separation device 4, the liquid outlet of the first gas-liquid separation device 4 is connected with the second fluid inlet of the heat exchanger 2, the second fluid outlet of the heat exchanger 2 is connected with the first inlet of the first compression device 5,

[0068] Wherein, the flue gas drying device 1 can dry other gases in addition to drying flue gas, as long as the device has a drying function and has no effect on the flue gas. The heat exchanger 2 is used for heat exchange treatment of the material, and the heat exchanger 2 can be classified in different ways. According to the operation process, it can be divided into three categories: mixed type, heat storage type (or called regenerative type), according to the compactness of the surface, it can be divided into two categories: compact type and non-compact type. The heat exchanger 2 in the embodiment can also store heat for subsequent processes. In the embodiment, the flue gas is first subjected to heat exchange treatment in the heat exchanger 2. The flue gas does not need to consume energy when it is subjected to heat exchange treatment in the heat exchanger 2. The present application can make the energy consumption of the subsequent flue gas in the first gas-liquid separation device 4 be less than that of the flue gas directly cooled in the first gas-liquid separation device 4. The first gas-liquid separation device 4 in the embodiment utilizes the physical properties of carbon dioxide to change the carbon dioxide in the flue gas into first liquid carbon dioxide by cooling and decompression, so that the flue gas is divided into first liquid carbon dioxide and first gas. After the first liquid carbon dioxide is separated in the first gas-liquid separation device 4, it needs to enter the heat exchanger 2 through the second fluid inlet of the heat exchanger 2 for heat exchange treatment, so as to be vaporized into first gaseous carbon dioxide.

[0069] Further, the heat required for the first liquid carbon dioxide to be subjected to heat exchange treatment in the heat exchanger 2 comes from the heat saved by the flue gas during heat exchange treatment in the heat exchanger 2, and no additional energy is used to heat the first liquid carbon dioxide, effectively reducing energy consumption. The first gaseous carbon dioxide is transported to the first compression device 5. The first compression device 5 is used to compress the first gaseous carbon dioxide to facilitate the sequestration of the first gaseous carbon dioxide.

[0070] The gas outlet of the first gas-liquid separation device 4 is connected with the third fluid inlet of the heat exchanger 2, and the third fluid outlet of the heat exchanger 2 is a gas outlet;

[0071] The first gas outlet of the first gas-liquid separation device 4 is used to release the first gas, which is the gas remaining after the first liquid carbon dioxide is filtered out from the flue gas in the first gas-liquid separation device 4. The first gas enters the heat exchanger 2 through the third fluid inlet of the heat exchanger 2 for heat exchange treatment. The heat required by the first gas for heat exchange treatment in the heat exchanger 2 comes from the heat preserved by the flue gas during heat exchange treatment in the heat exchanger 2, without using additional energy to heat other gases, thereby reducing energy consumption. Finally, the first gas after being heated is discharged, which can be discharged into the atmosphere or transported to other equipment for further processing.

[0072] The first fluid inlet is in communication with the first fluid outlet, the second fluid inlet is in communication with the second fluid outlet, and the third fluid inlet is in communication with the third fluid outlet.

[0073] The first fluid inlet and the first fluid outlet are connected by a channel, so that the substances in the pipeline are subjected to heat exchange treatment. The second fluid inlet and the second fluid outlet are connected by a channel, and the third fluid inlet and the third fluid outlet are connected by a channel.

[0074] The flue gas containing carbon dioxide is dried by the flue gas drying device 1, and the dried flue gas enters the heat exchanger 2 for heat exchange treatment. The flue gas is cooled again in the first gas-liquid separation device 4, and is separated into first liquid carbon dioxide and first gas. The first liquid carbon dioxide and the first gas are subjected to heat exchange treatment in the heat exchanger 2. After the first liquid carbon dioxide is subjected to heat exchange treatment, it is vaporized into first gaseous carbon dioxide. The first gaseous carbon dioxide is placed in the first compression device 5 for compression, and the first gas is discharged. The flue gas is first subjected to heat exchange treatment in the heat exchanger 2, thereby reducing the heat required for cooling the flue gas in the first gas-liquid separation device 4. When the first liquid carbon dioxide and the first gas are subjected to heat exchange treatment in the heat exchanger 2, the heat preserved by the flue gas during heat exchange treatment in the heat exchanger 2 is used, without using additional energy to vaporize the first liquid carbon dioxide or to heat the first gas, thereby realizing energy recycling and effectively saving energy.

[0075] As shown in Figure 3 and Figure 4 According to the flue gas carbon dioxide treatment system provided by the embodiment, the flue gas carbon dioxide treatment system further comprises a second gas-liquid separation device 7 for liquefying and gas-liquid separating the carbon dioxide,

[0076] The third fluid outlet is connected with the inlet of the second gas-liquid separation device 7, the liquid outlet of the second gas-liquid separation device 7 is connected with the fourth fluid inlet of the heat exchanger 2, and the fourth fluid outlet of the heat exchanger 2 is connected with the second inlet of the first compression device 5;

[0077] The first gas is cooled and decompressed in the second gas-liquid separation device 7, so that the carbon dioxide in the first gas is liquefied and separated from the first gas. The separated second liquid carbon dioxide enters the heat exchanger 2 through the fourth fluid inlet of the heat exchanger 2 for heat exchange treatment, and the second liquid carbon dioxide is vaporized into second gaseous carbon dioxide. The heat required for the heat exchange treatment of the second liquid carbon dioxide in the heat exchanger 2 comes from the heat preserved by the first gas after the heat exchange treatment in the heat exchanger 2, and no additional energy is used to heat the second liquid carbon dioxide, effectively reducing the consumption of energy. The second gaseous carbon dioxide is transported to the first compression device 5 through the pipeline, enters the first compression device 5 from the second inlet of the first compression device 5 for compression, and is convenient for subsequent gaseous carbon dioxide storage.

[0078] The gas outlet of the second gas-liquid separation device 7 is connected with the fifth fluid inlet of the heat exchanger 2, and the fifth fluid outlet of the heat exchanger 2 is a gas outlet;

[0079] The gas outlet of the second gas-liquid separation device 7 is used to release the second gas, and the second gas is the gas remaining after the second liquid carbon dioxide is filtered out from the first gas in the second gas-liquid separation device 7. The second gas enters the heat exchanger 2 through the fifth fluid inlet of the heat exchanger 2 for heat treatment, and the heat required for the heat exchange treatment of the second gas in the heat exchanger 2 comes from the heat preserved by the first gas after the heat treatment in the heat exchanger 2, without using additional heat to heat the second gas, thereby reducing the consumption of energy. The second gas after being heated is discharged through the fifth fluid outlet of the heat exchanger 2, and can be discharged into the atmosphere or transported to other equipment for other process treatment.

[0080] The fourth fluid inlet and the fourth fluid outlet are in communication, and the fifth fluid inlet and the fifth fluid outlet are in communication.

[0081] The fourth fluid inlet and the fourth fluid outlet are connected through the channel, so that the substances in the pipeline are subjected to heat exchange treatment. The fifth fluid inlet and the fifth fluid outlet are connected through the channel.

[0082] As shown in Figure 5 and Figure 6 According to the carbon dioxide treatment system in flue gas provided by the embodiment, the heat exchanger 2 comprises: a first heat exchanger 3 and a second heat exchanger 6;

[0083] The outlet of the flue gas drying device 1 is connected with the first fluid inlet of the heat exchanger 2, the first fluid outlet of the heat exchanger 2 is connected with the inlet of the first gas-liquid separation device 4, the liquid outlet of the first gas-liquid separation device 4 is connected with the second fluid inlet of the heat exchanger 2, and the second fluid outlet of the heat exchanger 2 is connected with the first inlet of the first compression device 5, which is specifically provided as follows:

[0084] The outlet of the flue gas drying device 1 is connected with the first fluid inlet of the first heat exchanger 3, the first fluid outlet of the first heat exchanger 3 is connected with the inlet of the first gas-liquid separation device 4, the liquid outlet of the first gas-liquid separation device 4 is connected with the second fluid inlet of the first heat exchanger 3, and the second fluid outlet of the first heat exchanger 3 is connected with the first inlet of the first compression device 5.

[0085] Wherein, the flue gas drying device 1 can dry other gases in addition to drying flue gas, as long as the device has a drying function and has no effect on the flue gas. The first heat exchanger 3 can store heat for subsequent processes. In this embodiment, the flue gas is first subjected to heat exchange treatment in the first heat exchanger 3. The flue gas does not need to consume energy when it is subjected to heat exchange treatment in the first heat exchanger 3. The present application can make the energy consumption of the subsequent flue gas in the first gas-liquid separation device 4 less than that of the direct cooling of the uncooled flue gas in the first gas-liquid separation device 4. The first gas-liquid separation device 4 in this embodiment utilizes the physical properties of carbon dioxide to change the carbon dioxide in the flue gas into first liquid carbon dioxide by cooling and decompression, so that the flue gas is divided into first liquid carbon dioxide and first gas. After the first liquid carbon dioxide is separated out in the first gas-liquid separation device 4, it needs to enter the first heat exchanger 3 through the second fluid inlet of the first heat exchanger 3 for heat exchange treatment, so as to be vaporized into gaseous carbon dioxide.

[0086] Further, the heat required for the first liquid carbon dioxide to exchange heat in the first heat exchanger 3 comes from the heat saved by the flue gas during heat exchange treatment in the first heat exchanger 3, and no additional heat is used to heat the first liquid carbon dioxide, effectively reducing energy consumption. The first gaseous carbon dioxide is transported to the first compression device 5. The first compression device 5 is used to compress carbon dioxide to facilitate carbon dioxide sequestration.

[0087] The gas outlet of the first gas-liquid separation device 4 is connected with the third fluid inlet of the heat exchanger 2, and the third fluid outlet of the heat exchanger 2 is a gas outlet, which is specifically provided as follows:

[0088] The gas outlet of the first gas-liquid separation device 4 is connected with the third fluid inlet of the second heat exchanger 6, and the third fluid outlet of the second heat exchanger 6 is a gas outlet;

[0089] The liquid outlet of the second gas-liquid separation device 7 is connected with the fourth fluid inlet of the heat exchanger 2, and the fourth fluid outlet of the heat exchanger 2 is connected with the second inlet of the first compression device 5, and specifically arranged as follows:

[0090] The liquid outlet of the second gas-liquid separation device 7 is connected with the fourth fluid inlet of the second heat exchanger 6, and the fourth fluid outlet of the second heat exchanger 6 is connected with the second inlet of the first compression device 5;

[0091] The gas outlet of the second gas-liquid separation device 7 is connected with the fifth fluid inlet of the heat exchanger 2, and the fifth fluid outlet of the heat exchanger 2 is a gas outlet, and specifically arranged as follows:

[0092] The gas outlet of the second gas-liquid separation device 7 is connected with the fifth fluid inlet of the second heat exchanger 6, and the fifth fluid outlet of the second heat exchanger 6 is a gas outlet.

[0093] The gas outlet of the first gas-liquid separation device 4 is used to release the first gas, which is the gas remaining after the first liquid carbon dioxide is filtered out from the flue gas in the first gas-liquid separation device 4. Some carbon dioxide is also contained in the remaining gas, which can be further extracted. The first gas enters the second heat exchanger 6 from the third fluid inlet of the second heat exchanger 6 through the pipeline connected with the second heat exchanger 6, and is subjected to heat exchange treatment in the second heat exchanger 6. The heat generated when the second heat exchanger 6 exchanges heat with the first gas is stored. The first gas after cooling is transported to the second gas-liquid separation device 7 for separation of the second liquid carbon dioxide. If there is carbon dioxide in the first gas, the carbon dioxide in the first gas is liquefied and separated from the first gas by cooling and decompressing the first gas in the second gas-liquid separation device 7 according to the properties of carbon dioxide. The separated second liquid carbon dioxide enters the second heat exchanger 6 through the fourth fluid inlet of the second heat exchanger 6 and is subjected to heat exchange treatment. The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide. The heat required for the second liquid carbon dioxide to be subjected to heat exchange treatment in the second heat exchanger 6 comes from the heat stored when the first gas is subjected to heat exchange treatment in the second heat exchanger 6, and no additional heat is used to heat the second liquid carbon dioxide, effectively reducing energy consumption. The second gaseous carbon dioxide is transported to the first compression device 5 through the pipeline and enters the first compression device 5 from the second inlet of the first compression device 5 for compression, which is convenient for subsequent carbon dioxide storage.

[0094] Further, the first inlet and the second inlet of the first compression device 5 can be the same inlet or different inlets.

[0095] The gas outlet of the second gas-liquid separation device 7 is connected with the fifth fluid inlet of the second heat exchanger 6, and the fifth fluid outlet of the second heat exchanger 6 is a gas outlet.

[0096] The second gas outlet of the second gas-liquid separation device 7 is used to release the second gas, which is the gas remaining after the second liquid carbon dioxide is filtered from the first gas in the second gas-liquid separation device 7. The second gas enters the second heat exchanger 6 through the fifth fluid inlet of the second heat exchanger 6 for heat exchange treatment. The heat required by the second gas for heat exchange treatment in the second heat exchanger 6 is the heat saved by the first gas for heat exchange treatment in the second heat exchanger 6, and no additional heat is used to heat the second gas, thereby reducing energy consumption. The second gas after being heated can be discharged to the atmosphere or transported to other equipment for further processing.

[0097] Further, the third fluid inlet of the second heat exchanger 6 is in communication with the third fluid outlet of the second heat exchanger 6, the fourth cold fluid inlet of the second heat exchanger 6 is in communication with the fourth fluid outlet of the second heat exchanger 6, and the fifth fluid inlet of the second heat exchanger 6 is in communication with the fifth fluid outlet of the second heat exchanger 6.

[0098] The first gas separated from the flue gas is transported to the second heat exchanger 6 for heat exchange treatment, and the first gas is cooled and decompressed in the second gas-liquid separation device 7. The first gas is divided into second liquid carbon dioxide and second gas. The second liquid carbon dioxide and the second gas are subjected to heat exchange treatment in the second heat exchanger 6, the second liquid carbon dioxide is vaporized into second gaseous carbon dioxide, the second gaseous carbon dioxide enters the first compression device 5 through the second inlet of the first compression device 5 for compression, and the second gas is discharged or transported to other equipment. First, the first gas is subjected to heat exchange treatment in the second heat exchanger 6, thereby reducing the heat required by the first gas for gas-liquid separation in the second gas-liquid separation device 7. The second liquid carbon dioxide and the second gas absorb the heat saved by the first gas for heat exchange treatment in the second heat exchanger 6, and no additional heat is used to vaporize the second liquid carbon dioxide and heat the second gas, thereby realizing energy recycling and effectively saving energy.

[0099] In Figure 3 Based on the flue gas carbon dioxide treatment system shown in Figure 7 Another flue gas carbon dioxide treatment system provided by the embodiment further comprises a second compression device 8,

[0100] The fourth fluid outlet is connected with the second inlet of the first compression device 5, and is specifically provided as:

[0101] The fourth fluid outlet is connected with the second inlet of the first compression device 5 through the second compression device 8.

[0102] The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide after heat exchange treatment in the heat exchanger 2, and the second gaseous carbon dioxide enters the second compression device 8 through the fourth fluid outlet for compression, and enters the first compression device 5 through the second inlet of the first compression device 5 for secondary compression after compression in the second compression device 8.

[0103] On the basis of the flue gas carbon dioxide treatment system shown in Figure 5 As shown in Figure 8 Another flue gas carbon dioxide treatment system provided by the embodiment further comprises a second compression device 8,

[0104] The fourth fluid outlet is connected with the second inlet of the first compression device 5, and is specifically provided as:

[0105] The fourth fluid outlet is connected with the second inlet of the first compression device 5 through the second compression device 8.

[0106] The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide after heat exchange treatment in the second heat exchanger 6, and the second gaseous carbon dioxide enters the second compression device 8 through the fourth fluid outlet for compression, and enters the first compression device 5 through the second inlet of the first compression device 5 for secondary compression after compression in the second compression device 8.

[0107] On the basis of the flue gas carbon dioxide treatment system shown in Figure 3 As shown in Figure 9 Another flue gas carbon dioxide treatment system provided by the embodiment further comprises a cooler 9,

[0108] The fourth fluid outlet is connected with the second inlet of the first compression device 5, and is specifically provided as:

[0109] The fourth fluid outlet is connected with the second inlet of the first compression device 5 through the cooler 9.

[0110] The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide after heat exchange treatment in the heat exchanger 2, and the second gaseous carbon dioxide enters the cooler 9 for cooling, and then enters the first compression device 5 through the second inlet of the first compression device 5 for compression.

[0111] In Figure 5 Based on the flue gas carbon dioxide treatment system shown in Figure 10 As shown in the flue gas carbon dioxide treatment system shown in

[0112] The fourth fluid outlet is connected with the second inlet of the first compression device 5, and is specifically provided as:

[0113] The fourth fluid outlet is connected with the second inlet of the first compression device 5 through the cooler 9.

[0114] The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide after heat exchange treatment in the second heat exchanger 6, and the gaseous carbon dioxide enters the cooler 9 for cooling and then enters the first compression device 5 through the second inlet of the first compression device 5 for compression.

[0115] In Figure 7 Based on the flue gas carbon dioxide treatment system shown in Figure 11 As shown in the flue gas carbon dioxide treatment system shown in

[0116] The fourth fluid outlet is connected with the second inlet of the first compression device 5, and is specifically provided as:

[0117] The fourth fluid outlet is connected with the second inlet of the first compression device 5 through the second compression device 8 and the cooler 9.

[0118] The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide after heat exchange treatment in the heat exchanger 2, the second gaseous carbon dioxide enters the second compression device 8 through the fourth fluid outlet for compression, and then enters the cooler 9 for cooling after compression in the second compression device 8, and finally enters the first compression device 5 through the second inlet of the first compression device 5 for secondary compression after cooling.

[0119] In Figure 8 Based on the flue gas carbon dioxide treatment system shown in Figure 12 As shown in the flue gas carbon dioxide treatment system shown in

[0120] The fourth fluid outlet is connected with the second inlet of the first compression device 5, and is specifically provided as:

[0121] The fourth fluid outlet is connected with the second inlet of the first compression device 5 through the second compression device 8 and the cooler 9.

[0122] The second liquid carbon dioxide is vaporized into second gaseous carbon dioxide after heat exchange treatment in the second heat exchanger 6, enters the second compression device 8 through the fourth fluid outlet for compression, enters the cooler 9 for cooling after compression in the second compression device 8, and finally enters the first compression device 5 through the second inlet of the first compression device 5 for secondary compression.

[0123] The gas temperature of the gas outlet of the first gas-liquid separation device 4 is -50 to -55℃ in the carbon dioxide treatment system for flue gas provided by the embodiment.

[0124] And / or,

[0125] The gas pressure of the gas outlet of the first compression device 5 is 11 MPa.

[0126] The gas temperature of the gas outlet of the second gas-liquid separation device 7 can also be -50 to -55℃, the gas temperature is the temperature of the gas outlet of the first gas-liquid separation device 4 in the embodiment, the gas pressure is the pressure of the gas outlet of the first compression device 5 in the embodiment, and the temperature and pressure of other gas outlets are not limited.

[0127] The first heat exchanger 3 and the second heat exchanger 6 are the same heat exchanger or different heat exchangers in the carbon dioxide treatment system for flue gas provided by the embodiment.

[0128] On the basis of the above-mentioned embodiment of the carbon dioxide treatment system for flue gas, the application further provides a carbon dioxide purification method for flue gas.

[0129] As shown in Figure 13 The carbon dioxide purification method for flue gas provided by the embodiment of the application is applied to the carbon dioxide treatment system for flue gas shown in Figure 1 The method comprises the following steps.

[0130] S50, drying the flue gas containing carbon dioxide in the flue gas drying equipment 1;

[0131] S51, performing heat exchange treatment on the dried flue gas containing carbon dioxide in the heat exchanger 2;

[0132] S52, cooling and decompressing the flue gas containing carbon dioxide after heat exchange treatment in the first gas-liquid separation device 4 to obtain first liquid carbon dioxide and first gas;

[0133] S53, performing heat exchange treatment on the first liquid carbon dioxide in the heat exchanger 2 to vaporize the first liquid carbon dioxide into first gaseous carbon dioxide;

[0134] S54, compressing the first gaseous carbon dioxide in the first compression device 5;

[0135] S55, performing heat exchange treatment on the first gas in the heat exchanger 2, and discharging the first gas after the heat exchange treatment.

[0136] Figure 13 The processes in the method have been described in the above-mentioned embodiments, and will not be repeated here. Figure 1 The processes in the method have been described in the above-mentioned embodiments, and will not be repeated here.

[0137] As shown in the above-mentioned embodiments, in the method for purifying carbon dioxide from flue gas according to the present embodiment, in the case where the system for treating carbon dioxide from flue gas further comprises a second gas-liquid separation device 7 for liquefying the carbon dioxide and performing gas-liquid separation, the method further comprises: Figure 14 S60, cooling and decompressing the discharged first gas in the second gas-liquid separation device 7 to obtain second liquid carbon dioxide and second gas;

[0138] S61, performing heat exchange treatment on the second liquid carbon dioxide in the heat exchanger 2 to vaporize the second liquid carbon dioxide into second gaseous carbon dioxide;

[0139] S62, compressing the second gaseous carbon dioxide in the first compression device 5;

[0140] S63, performing heat exchange treatment on the second gas in the heat exchanger 2, and discharging the second gas after the heat exchange treatment.

[0141]

[0142] The processes in the method have been described in the above-mentioned embodiments, and will not be repeated here. Figure 14 The processes in the method have been described in the above-mentioned embodiments, and will not be repeated here. Figure 3 Finally, it should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0143]

[0144] ​The various embodiments described in this specification are intended to be illustrative only and in no way limit the scope of the application. Changes and modifications can be made to these embodiments without departing from the spirit or scope of the application. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present application.

[0145] The above description of disclosed embodiments is intended to be illustrative only and not limiting of the scope of the application. Numerous modifications to these embodiments can be apparent to those skilled in the art without departing from the spirit or scope of the application. Accordingly, the specification is to be regarded as illustrative rather than restrictive, and all such modifications are intended to be included within the scope of the present application.

Claims

1. A system for treating carbon dioxide in flue gas, characterized by, The flue gas carbon dioxide treatment system comprises a flue gas drying device, a heat exchanger, a first compression device, a first gas-liquid separation device for liquefying carbon dioxide and performing gas-liquid separation, and a second gas-liquid separation device; The flue gas drying device is connected with the first fluid inlet of the heat exchanger, the first fluid outlet of the heat exchanger is connected with the inlet of the first gas-liquid separation device, the liquid outlet of the first gas-liquid separation device is connected with the second fluid inlet of the heat exchanger, and the second fluid outlet of the heat exchanger is connected with the first inlet of the first compression device; The gas outlet of the first gas-liquid separation device is connected with the third fluid inlet of the heat exchanger, and the third fluid outlet of the heat exchanger is a gas outlet; The third fluid outlet is connected with the inlet of the second gas-liquid separation device, the liquid outlet of the second gas-liquid separation device is connected with the fourth fluid inlet of the heat exchanger, and the fourth fluid outlet of the heat exchanger is connected with the second inlet of the first compression device; The gas outlet of the second gas-liquid separation device is connected with the fifth fluid inlet of the heat exchanger, and the fifth fluid outlet of the heat exchanger is a gas outlet; The first fluid inlet is in communication with the first fluid outlet, the second fluid inlet is in communication with the second fluid outlet, the third fluid inlet is in communication with the third fluid outlet, the fourth fluid inlet is in communication with the fourth fluid outlet, and the fifth fluid inlet is in communication with the fifth fluid outlet; The heat exchanger comprises a first heat exchanger and a second heat exchanger; The flue gas drying device is connected with the first fluid inlet of the first heat exchanger, the first fluid outlet of the first heat exchanger is connected with the inlet of the first gas-liquid separation device, the liquid outlet of the first gas-liquid separation device is connected with the second fluid inlet of the first heat exchanger, and the second fluid outlet of the first heat exchanger is connected with the first inlet of the first compression device; The gas outlet of the first gas-liquid separation device is connected with the third fluid inlet of the second heat exchanger, and the third fluid outlet of the second heat exchanger is a gas outlet; The liquid outlet of the second gas-liquid separation device is connected with the fourth fluid inlet of the second heat exchanger, and the fourth fluid outlet of the second heat exchanger is connected with the second inlet of the first compression device; The gas outlet of the second gas-liquid separation device is connected with the fifth fluid inlet of the second heat exchanger, and the fifth fluid outlet of the second heat exchanger is a gas outlet; The heat required by the first liquid carbon dioxide for heat exchange treatment in the first heat exchanger comes from the heat preserved by the flue gas during heat exchange treatment in the first heat exchanger, the heat required by the second liquid carbon dioxide for heat exchange treatment in the second heat exchanger comes from the heat preserved by the first gas during heat exchange treatment in the second heat exchanger, and the first gas is the gas remaining after the flue gas filters out the first liquid carbon dioxide in the first gas-liquid separation device.

2. The system of claim 1, wherein, The carbon dioxide treatment system in the flue gas further comprises a second compression device; The fourth fluid outlet is connected with the second inlet of the first compression device, and is specifically provided as: The fourth fluid outlet is connected with the second inlet of the first compression device through the second compression device.

3. The system of claim 1, wherein, The carbon dioxide treatment system in the flue gas further comprises a cooler; The fourth fluid outlet is connected with the second inlet of the first compression device, and is specifically provided as: The fourth fluid outlet is connected with the second inlet of the first compression device through the cooler.

4. The system of claim 2, wherein, The carbon dioxide treatment system in the flue gas further comprises a cooler; The fourth fluid outlet is connected with the second inlet of the first compression device, and is specifically provided as: The fourth fluid outlet is connected with the second inlet of the first compression device through the second compression device and the cooler.

5. The system for treating carbon dioxide in flue gas of claim 1, wherein, The gas temperature of the gas outlet of the first gas-liquid separation device is-50 to-55℃; And / or, The gas pressure of the gas outlet of the first compression device is 11 MPa.

6. The system for treating carbon dioxide in flue gas of claim 1, wherein, The first heat exchanger and the second heat exchanger are the same heat exchanger or different heat exchangers.

7. A method for purifying carbon dioxide from flue gas, characterized by, The method applied to the carbon dioxide treatment system in the flue gas in any one of claims 1 to 6, the method comprises: Drying the flue gas containing carbon dioxide in the flue gas drying device; Heat exchange treatment of the dried flue gas containing carbon dioxide in the heat exchanger; Cooling and decompression of the flue gas containing carbon dioxide after heat exchange treatment in the first gas-liquid separation device to obtain first liquid carbon dioxide and first gas; Heat exchange treatment of the first liquid carbon dioxide in the heat exchanger to vaporize the first liquid carbon dioxide into first gaseous carbon dioxide; Compression of the first gaseous carbon dioxide in the first compression device; Heat exchange treatment of the first gas in the heat exchanger to discharge the first gas after heat exchange treatment; Cooling and decompression of the discharged first gas in the second gas-liquid separation device to obtain second liquid carbon dioxide and second gas; Heat exchange treatment of the second liquid carbon dioxide in the heat exchanger to vaporize the second liquid carbon dioxide into second gaseous carbon dioxide; Compression of the second gaseous carbon dioxide in the first compression device; Heat exchange treatment of the second gas in the heat exchanger to discharge the second gas after heat exchange treatment; The heat exchanger comprises a first heat exchanger and a second heat exchanger, and the above process can be specifically as follows: Drying the flue gas containing carbon dioxide in the flue gas drying device; Heat exchange treatment of the dried flue gas containing carbon dioxide in the first heat exchanger; Cooling and decompression of the flue gas containing carbon dioxide after heat exchange treatment in the first gas-liquid separation device to obtain first liquid carbon dioxide and first gas; Heat exchange treatment of the first liquid carbon dioxide in the first heat exchanger to vaporize the first liquid carbon dioxide into first gaseous carbon dioxide; The first gaseous carbon dioxide is compressed in the first compression device; The first gas is subjected to heat exchange treatment in the second heat exchanger, and the first gas after heat exchange treatment is discharged; The discharged first gas is subjected to temperature and pressure reduction in the second gas-liquid separation device, and second liquid carbon dioxide and second gas are obtained; The second liquid carbon dioxide is subjected to heat exchange treatment in the second heat exchanger, so that the second liquid carbon dioxide is vaporized into second gaseous carbon dioxide; The second gaseous carbon dioxide is compressed in the first compression device; The second gas is subjected to heat exchange treatment in the second heat exchanger, and the second gas after heat exchange treatment is discharged; The heat required by the first liquid carbon dioxide for heat exchange treatment in the first heat exchanger comes from the heat preserved by the flue gas during heat exchange treatment in the first heat exchanger, and the heat required by the second liquid carbon dioxide for heat exchange treatment in the second heat exchanger comes from the heat preserved by the first gas during heat exchange treatment in the second heat exchanger, wherein the first gas is the gas remaining after the flue gas filters out the first liquid carbon dioxide in the first gas-liquid separation device.

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