Carbon dioxide adsorption system

Abstract

The present invention relates to the field of carbon capture technology, and provides a carbon dioxide adsorption system, including: a first compressor unit, a temperature swing adsorption unit and a vacuum pressure swing adsorption unit connected in sequence to the rear end of the raw gas inlet; a turbine expansion unit, whose inlet is connected to the first outlet of the vacuum pressure swing adsorption unit, and the turbine expansion unit is connected to the first compressor unit; a cold recovery unit, whose first inlet is connected to the outlet of the turbine expansion unit, whose second inlet is connected to the second outlet of the vacuum pressure swing adsorption unit, and whose cold recovery unit is provided with a decarbonated carbon dioxide raw material outlet; a first separator, whose inlet is connected to the first outlet of the cold recovery unit, whose first outlet is connected to the third inlet of the cold recovery unit, whose second outlet is connected to the inlet of the vacuum pressure swing adsorption unit, and whose second outlet is connected to the carbon dioxide liquid outlet. The present invention effectively improves the CO2 capture efficiency, reduces the equipment size, reduces the CO2 capture and liquefaction energy consumption, simplifies the process flow, and is suitable for large-scale application.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, in particular to a carbon dioxide adsorption system. Background Art

[0002] The capture of carbon dioxide (CO2) in flue gas is the main scenario of carbon capture in the future, which meets the needs of environmental protection. At present, the main methods for achieving carbon dioxide capture are chemical absorption and adsorption.

[0003] The chemical absorption method has problems such as high energy consumption and solvent corrosion. Although a lot of energy-saving process improvements have been made, the theoretical regeneration energy consumption of 2.0GJ / t of carbon dioxide is basically close to the limit, and the potential for further tapping and reducing consumption is limited.

[0004] The adsorption method conventionally adopts low-pressure adsorption (1barg-2barg). Although it has the characteristics of low energy consumption and environmental friendliness compared with the chemical absorption method, due to the large flue gas volume, low pressure, and low carbon dioxide concentration, the low-pressure adsorption method has low carbon dioxide single-pass capture efficiency and often requires two sets of pressure swing adsorption (PSA) or membrane separation + pressure swing adsorption in series, resulting in long process flow, large equipment, and difficulty in large-scale application.

[0005] The pressurized adsorption method can improve the carbon dioxide capture efficiency and reduce the size of the equipment, but there is a challenge of high energy consumption for flue gas pressurization, which limits the large-scale application of the adsorption method.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0007] In view of this, the present invention provides a carbon dioxide adsorption system, which can effectively improve the carbon dioxide capture efficiency, reduce the equipment size, and reduce the energy consumption of carbon dioxide capture and liquefaction, simplify the process flow, and is suitable for large-scale application.

[0008] According to one aspect of the present invention, there is provided a carbon dioxide adsorption system, comprising: a first compressor unit, wherein the inlet of the first compressor unit is connected to the raw gas inlet, and the pressure of the outlet of the first compressor unit is 0.9 MPag to 2.0 MPag; a temperature swing adsorption unit, wherein the outlet of the first compressor unit is connected to the inlet of the temperature swing adsorption unit; a vacuum pressure swing adsorption unit, wherein the outlet of the temperature swing adsorption unit is connected to the inlet of the vacuum pressure swing adsorption unit, the first outlet of the vacuum pressure swing adsorption unit discharges non-adsorbed gas and the second outlet discharges desorbed gas having a CO2 volume content higher than 90%; a turbine expansion unit, wherein the first outlet of the vacuum pressure swing adsorption unit is connected to the inlet of the turbine expansion unit, the turbine expansion unit is connected to the first compressor unit, the turbine expansion unit performs turbine expansion on the non-adsorbed gas discharged from the vacuum pressure swing adsorption unit, and uses the gas after turbine expansion to push the first compressor unit to pressurize the raw gas; a third compressor unit, wherein the inlet of the third compressor unit is connected to the second outlet of the vacuum pressure swing adsorption unit, and the third compressor unit The temperature of the outlet is 30℃~50℃; a cold recovery unit, the outlet of the turbine expansion unit is connected to the first inlet of the cold recovery unit, the outlet of the third compressor unit is connected to the second inlet of the cold recovery unit, the temperatures of the first and second outlets of the cold recovery unit are -20℃~-60℃, and the cold recovery unit is also provided with a decarbonation raw material outlet; a first separator, the first outlet of the cold recovery unit is connected to the inlet of the first separator, the first outlet of the first separator is connected to the third inlet of the cold recovery unit through a throttling expansion valve, so that the cold recovery unit recovers the cold after throttling expansion, the temperature range of the cold after throttling expansion is -50℃~-90℃, the second outlet of the cold recovery unit is connected to the inlet of the vacuum pressure swing adsorption unit, and the second outlet of the first separator is connected to the carbon dioxide liquid outlet; wherein, the cold recovery unit recovers the cold after turbine expansion of the turbine expansion unit and the cold after throttling expansion of the throttling expansion valve, and cools the gas pressurized by the third compressor unit.

[0009] In some embodiments, the temperature of the outlet of the first compressor unit is 100°C to 150°C; the dew point temperature of the outlet of the temperature swing adsorption unit is -30°C to -60°C; the pressure of the first outlet of the vacuum pressure swing adsorption unit is 0.4MPag to 2.0MPag, and the temperature is 20°C to 40°C; the pressure of the outlet of the turbine expansion unit is 0.01MPag to 0.05MPag, and the temperature is -40°C to -70°C.

[0010] In some embodiments, the adsorbent in the temperature swing adsorption unit is a combination of one or more of alumina, activated carbon, silica gel, molecular sieve and MOFs adsorbents; the adsorbent in the vacuum pressure swing adsorption unit is a combination of one or more of alumina, activated carbon, silica gel, molecular sieve and MOFs adsorbents.

[0011] In some embodiments, the carbon dioxide adsorption system also includes: a second compressor unit connected between the raw gas inlet and the inlet of the first compressor unit; wherein the pressure at the outlet of the second compressor unit is 0.2MPag~1.0MPag and the temperature is 30℃~50℃.

[0012] In some embodiments, the carbon dioxide adsorption system further comprises: a washing and cooling unit connected between the raw gas inlet and the inlet of the second compressor unit; wherein the outlet temperature of the washing and cooling unit is 30°C to 50°C.

[0013] In some embodiments, the carbon dioxide adsorption system further includes: a vacuum pump connected between the second outlet of the vacuum pressure swing adsorption unit and the second inlet of the cold recovery unit.

[0014] In some embodiments, the outlet pressure of the third compressor unit is 3.5 MPag to 8.0 MPag.

[0015] In some embodiments, the carbon dioxide adsorption system further includes: a second separator, wherein the first outlet of the first separator is connected to the inlet of the second separator, the first outlet of the second separator is connected to the third inlet of the cold recovery unit through the throttling expansion valve, and the second outlet of the second separator is connected to the carbon dioxide liquid outlet.

[0016] In some embodiments, the carbon dioxide adsorption system further comprises: a condenser connected between the first outlet of the first separator and the inlet of the second separator; wherein the temperature of the outlet of the condenser is -30°C to -70°C.

[0017] In some embodiments, the raw gas introduced into the raw gas inlet is boiler flue gas, catalytic coking flue gas, hydrogen production cracking furnace flue gas or industrial furnace flue gas.

[0018] The beneficial effects of the present invention compared with the prior art include at least:

[0019] The carbon dioxide adsorption system of the present invention, through a compressor unit including a first compressor unit, utilizes a pressurized adsorption method to effectively increase the carbon dioxide partial pressure, thereby greatly improving the carbon dioxide adsorption performance, thereby improving the efficiency of carbon capture by adsorption and the carbon dioxide concentration in the desorbed gas; in this way, a set of variable temperature adsorption units can be used to complete the separation, reduce the equipment size and adsorption cost, and simplify the process flow; after the operating pressure is increased, the volume flow rate of the raw gas is lower, and the size of the supporting equipment is smaller, which is conducive to large-scale application.

[0020] Since the pressurized adsorption method is adopted, the operating pressure is high, resulting in increased energy consumption for raw gas compression. The carbon dioxide adsorption system of the present invention utilizes the flue gas boost energy storage principle, and utilizes the fact that about 80% to 90% of the flue gas after the vacuum pressure swing adsorption (VPSA) unit is non-adsorbed gas, and the pressure drop of the non-adsorbed gas is smaller than the pressure drop of the raw gas (equivalent to pressure energy storage of the non-adsorbed gas). The compression-turbine expansion unit formed by connecting the first compressor unit through the turbine expansion unit recovers the pressure energy of the non-adsorbed gas of the vacuum pressure swing adsorption unit, realizes the "turbine expansion-raw material boosting" energy-saving process, greatly reduces the power consumption of the compressor unit, and thus reduces the energy consumption of carbon dioxide capture.

[0021] The carbon dioxide adsorption system of the present invention also uses a cold energy recovery unit. On the one hand, it utilizes the cold energy of the non-adsorbed gas in the vacuum pressure swing adsorption unit that has greatly dropped in temperature after being expanded by a turbine to do external work, which is used for carbon dioxide liquefaction to reduce the energy consumption of carbon dioxide liquefaction. On the other hand, it recovers the cold energy of the non-condensable gas in the separator gas phase to achieve full cold energy recovery, and then returns it to the vacuum pressure swing adsorption unit to further recover carbon dioxide, thereby achieving dual recovery of cold energy and carbon dioxide gas.

[0022] The carbon dioxide adsorption system of the present invention can effectively improve the carbon dioxide capture efficiency, reduce the size of the equipment, and reduce the energy consumption of carbon dioxide capture and liquefaction, simplify the process flow, is suitable for large-scale application, and achieves environmental protection.

[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification are used to explain the principles of the present invention. Obviously, the accompanying drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0025] Figure 1A schematic structural diagram of a carbon dioxide adsorption system in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0026] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments described herein. Instead, these embodiments are provided to make the present invention more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art.

[0027] The accompanying drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0028] The words "first", "second" and the like used in the specific description do not indicate any order, quantity or importance, but are only used to distinguish different components. In addition, in the description of the present invention, when it is said that a certain component is "connected" to another component, this includes not only the case of direct connection, but also the case of indirect connection through other components.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and features in different embodiments may be combined with each other.

[0030] Figure 1 The structure of the carbon dioxide adsorption system is shown schematically, referring to Figure 1 As shown, the carbon dioxide adsorption system provided by the embodiment of the present invention includes:

[0031] A first compressor unit 31, wherein the inlet of the first compressor unit 31 is connected to the raw gas inlet A;

[0032] The temperature swing adsorption unit 40, the outlet of the first compressor unit 31 is connected to the inlet of the temperature swing adsorption unit 40;

[0033] The vacuum pressure swing adsorption unit 50, the outlet of the temperature swing adsorption unit 40 is connected to the inlet of the vacuum pressure swing adsorption unit 50; the first outlet of the vacuum pressure swing adsorption unit 50 discharges non-adsorbed gas and the second outlet discharges desorbed gas with high CO2 content;

[0034] The turbine expansion unit 32, the first outlet of the vacuum pressure swing adsorption unit 50 is connected to the inlet of the turbine expansion unit 32, and the turbine expansion unit 32 is connected to the first compressor unit 31; wherein the turbine expansion unit 32 can be connected to the first compressor unit 31, for example, via a clutch;

[0035] The cold recovery unit 80, the outlet of the turbine expansion unit 32 is connected to the first inlet of the cold recovery unit 80, the second outlet of the vacuum pressure swing adsorption unit 50 is connected to the second inlet of the cold recovery unit 80, and the cold recovery unit 80 is provided with a decarbonation raw material outlet B;

[0036] The first separator 91, the first outlet of the cold recovery unit 80 is connected to the inlet of the first separator 91, the first outlet of the first separator 91 is connected to the third inlet of the cold recovery unit 80, the second outlet of the cold recovery unit 80 is connected to the inlet of the vacuum pressure swing adsorption unit 50, and the second outlet of the first separator 91 is connected to the carbon dioxide liquid outlet C.

[0037] The carbon dioxide adsorption system of the present invention, through a compressor unit including a first compressor unit 31, effectively increases the carbon dioxide partial pressure by pressurized adsorption, thereby greatly improving the carbon dioxide adsorption performance, thereby improving the efficiency of carbon capture by adsorption and the carbon dioxide concentration in the desorbed gas; in this way, a set of variable temperature adsorption units 40 can be used to complete the separation, reduce the equipment size and adsorption cost, and simplify the process flow; after the operating pressure is increased, the volume flow rate of the raw gas is lower, and the size of the supporting equipment is smaller, which is conducive to large-scale application.

[0038] In a preferred embodiment, the second outlet of the vacuum pressure swing adsorption unit 50 discharges desorbed gas having a CO2 volume content higher than 90%.

[0039] Due to the use of pressurized adsorption, the operating pressure is high, resulting in increased energy consumption for raw gas compression. The carbon dioxide adsorption system of the present invention utilizes the flue gas boost energy storage principle, and utilizes the fact that about 80% to 90% of the flue gas after the vacuum pressure swing adsorption unit is non-adsorbed gas, and the pressure drop of the non-adsorbed gas is smaller than the pressure drop of the raw gas (equivalent to pressure energy storage for the non-adsorbed gas). The compression-turbine expansion unit 30 formed by connecting the first compressor unit 31 through the turbine expansion unit 32 recovers the pressure energy of the non-adsorbed gas of the vacuum pressure swing adsorption unit 50, realizes the "turbine expansion-raw material boosting" energy-saving process, greatly reduces the power consumption of the compressor unit, and thus reduces the energy consumption of carbon dioxide capture. Specifically, the turbine expansion unit 32 performs turbine expansion on the non-adsorbed gas discharged from the vacuum pressure swing adsorption unit 50, and uses the gas after turbine expansion to drive the first compressor unit 31 to boost the raw gas.

[0040] The carbon dioxide adsorption system of the present invention also uses a cold energy recovery unit 80. On the one hand, it utilizes the cold energy of the non-adsorbed gas in the vacuum pressure swing adsorption unit 50, which is greatly reduced in temperature after the non-adsorbed gas is expanded by the turbine to do external work, for carbon dioxide liquefaction, thereby reducing the energy consumption of carbon dioxide liquefaction. On the other hand, it recovers the cold energy of the non-condensable gas in the separator gas phase, thereby achieving full cold energy recovery, and then returns it to the vacuum pressure swing adsorption unit 50 to further recover carbon dioxide, thereby achieving dual recovery of cold energy and carbon dioxide gas.

[0041] The carbon dioxide adsorption system of the present invention can effectively improve the carbon dioxide capture efficiency, reduce the size of the equipment, and reduce the energy consumption of carbon dioxide capture and liquefaction, simplify the process flow, is suitable for large-scale application, and achieves environmental protection.

[0042] In some embodiments, the raw gas S-1 introduced into the raw gas inlet A is boiler flue gas, catalytic coking flue gas, hydrogen cracking furnace flue gas or industrial furnace flue gas.

[0043] In some embodiments, the outlet pressure of the first compressor unit 31 is 0.4 MPag to 2.0 MPag, and the temperature is 30° C. to 130° C.; for example, the outlet pressure of the first compressor unit 31 is 0.9 MPag, and the temperature is 125° C., but not limited thereto.

[0044] Thanks to the action of the turbine expansion unit 32, the pressure and temperature at the outlet of the first compressor unit 31 can be higher; for example, in a preferred embodiment, the pressure at the outlet of the first compressor unit 31 is 0.9MPag~2.0MPag, and the temperature is 100℃~150℃.

[0045] In some embodiments, the dew point temperature at the outlet of the temperature swing adsorption unit 40 is -30°C to -60°C; for example, the dew point temperature at the outlet of the temperature swing adsorption unit 40 is -40°C, but is not limited thereto.

[0046] In some embodiments, the pressure at the first outlet of the vacuum pressure swing adsorption unit 50 is 0.4 MPag to 2.0 MPag and the temperature is 20° C. to 40° C.; for example, the pressure at the first outlet of the vacuum pressure swing adsorption unit 50 is 0.8 MPag and the temperature is 30° C., but not limited thereto.

[0047] In some embodiments, the outlet pressure of the turbine expansion unit 32 is 0.01 MPag to 0.05 MPag, and the temperature is -40°C to -70°C; for example, the outlet pressure of the turbine expansion unit 32 is 0.02 MPag, and the temperature is -60°C, but not limited thereto.

[0048] In some embodiments, the temperature of the first outlet and the second outlet of the cold recovery unit 80 is -20°C to -60°C; for example, the outlet temperature of the cold recovery unit 80 is -30°C, but not limited thereto.

[0049] In some embodiments, the adsorbent in the temperature swing adsorption unit 40 is a combination of one or more of alumina, activated carbon, silica gel, molecular sieve and MOFs (Metal Organic Frameworks) adsorbents, which can be specifically designed according to the properties of the raw gas S-1 and the dehydration index requirements; the adsorbent in the vacuum pressure swing adsorption unit 50 is a combination of one or more of alumina, activated carbon, silica gel, molecular sieve and MOFs adsorbents, which can be specifically designed according to the properties of the raw gas S-1 and the decarbonation index requirements. The CO2 adsorption performance of MOFs adsorbent is 3-5 times that of existing traditional adsorbents, which can greatly improve the capture efficiency of CO2 in flue gas.

[0050] In some embodiments, the carbon dioxide adsorption system further includes: a second compressor unit 20 connected between the raw gas inlet A and the inlet of the first compressor unit 31. The two-stage compression of the second compressor unit 20 and the first compressor unit 31 ensures that the raw gas S-1 is properly pressurized.

[0051] The pressure at the outlet of the second compressor unit 20 is 0.2 MPag to 1.0 MPag, and the temperature is 30° C. to 50° C. For example, the pressure at the outlet of the second compressor unit 20 is 0.4 MPag, and the temperature is 40° C., but the present invention is not limited thereto.

[0052] In some embodiments, the carbon dioxide adsorption system further includes: a washing and cooling unit 10, connected between the raw gas inlet A and the inlet of the second compressor unit 20. The washing and cooling unit 10 can wash and cool the raw gas S-1 to improve the cleanliness of the raw gas S-1.

[0053] The temperature of the outlet of the washing and cooling unit 10 is 30° C. to 50° C. For example, the temperature of the outlet of the washing and cooling unit 10 is 40° C., but not limited thereto.

[0054] In some embodiments, the carbon dioxide adsorption system further includes: a vacuum pump 60 connected between the second outlet of the vacuum pressure swing adsorption unit 50 and the second inlet of the cold recovery unit 80 .

[0055] In some embodiments, the carbon dioxide adsorption system further includes: a third compressor unit 70, connected between the outlet of the vacuum pump 60 and the second inlet of the cold recovery unit 80. The outlet pressure of the third compressor unit 70 is 2.0 MPag to 4.0 MPag, and the temperature is 30° C. to 50° C. For example, the outlet pressure of the third compressor unit 70 is 3.0 MPag, and the temperature is 40° C., but not limited thereto.

[0056] In some embodiments, the outlet pressure of the third compressor unit 70 can be higher, for example, 3.5 MPag to 8.0 MPag; further, the temperature of the final CO2 liquid product is 0 to -25°C.

[0057] In some embodiments, the carbon dioxide adsorption system also includes: a second separator 96, the first outlet of the first separator 91 is connected to the inlet of the second separator 96, the first outlet of the second separator 96 is connected to the third inlet of the cold recovery unit 80 through the throttling expansion valve 97, and the second outlet of the second separator 96 is connected to the carbon dioxide liquid outlet C.

[0058] The CO2 is fully separated by using the two-stage separators of the first separator 91 and the second separator 96.

[0059] In some embodiments, the carbon dioxide adsorption system further includes: a condenser 93 connected between the first outlet of the first separator 91 and the inlet of the second separator 96. The temperature of the outlet of the condenser 93 is -30°C to -70°C. For example, the temperature of the outlet of the condenser 93 is -50°C, but not limited thereto.

[0060] In some specific implementation scenarios, using Figure 1 The process flow of CO2 capture and liquefaction by the carbon dioxide adsorption system shown includes:

[0061] The raw gas S-1 containing CO2 transported from upstream enters the washing and cooling unit 10, which cools the raw gas S-1 to about 40°C; the raw gas S-2 after washing and cooling enters the second compressor unit 20, which pressurizes the raw gas S-2 after washing and cooling to about 0.4MPag; the pressurized raw gas S-3 enters the first compressor unit 31 and is pressurized again to about 0.9MPag and a temperature of about 125°C; the raw gas S-4 after being pressurized and heated again enters the temperature swing adsorption unit 40 for compression heat regeneration drying and dehydration, and the dew point temperature of the raw gas S-5 after compression heat regeneration drying and dehydration is controlled at about -40°C; then the raw gas S-5 after compression heat regeneration drying and dehydration enters the vacuum pressure swing adsorption unit 50 for CO2 adsorption separation, so that CO2 is adsorbed by the adsorbent, and the raw gas S-7 after CO2 removal is discharged from the first outlet of the vacuum pressure swing adsorption unit 50, with a pressure of about 0.8MPag and a temperature of about 40°C.

[0062] The CO2-free raw gas S-7 discharged from the first outlet of the vacuum pressure swing adsorption unit 50 enters the turbine expansion unit 32 for expansion and pressure recovery, driving the first compressor unit 31 to pressurize the pressurized raw gas S-3 to 0.9MPag; the pressure of the CO2-free raw gas S-8 after turbine expansion is reduced from 0.8MPag to 0.02MPag and the temperature is about -60°C, and then enters the first inlet of the cold recovery unit 80, and the cold recovery unit 80 recovers this part of the cold for CO2 liquefaction.

[0063] The desorbed gas S-10 with high CO2 content is discharged from the second outlet of the vacuum pressure swing adsorption unit 50, which is extracted by the vacuum pump 60 to form the desorbed gas S-11, and then enters the third compressor unit 70 to be pressurized to a pressure of about 3.0 MPag and a temperature of about 40°C to form the pressurized desorbed gas S-12 and transported to the second inlet of the cold recovery unit 80. The cold recovery unit 80 uses the raw gas S-8 after CO2 removal after turbine expansion and the gas S-20 after throttling to exchange heat with the pressurized desorbed gas S-12, fully recovering the two colds of S-8 and S-20, and the gas-liquid mixture S-13 after heat exchange is cooled to about -30°C, and enters the first separator 91 from the first outlet of the cold recovery unit 80 to obtain the first CO2 liquid product S-15 and the first non-condensable gas S-14 respectively.

[0064] The temperature range of the cold after throttling expansion is -50° C. to -90° C. The cold recovery unit 80 recovers the cold after turbine expansion and the cold after throttling expansion, and effectively cools the gas pressurized by the third compressor unit 70 .

[0065] Then, the first non-condensable gas S-14 enters the condenser 93, and is further cooled and condensed to -50°C. The gas-liquid mixture S-16 after cooling and condensation enters the second separator 96, and the second CO2 liquid product S-17 and the second non-condensable gas S-19 are obtained respectively, wherein the first CO2 liquid product S-15 and the second CO2 liquid product S-17 are combined and output as CO2 liquid product. The second non-condensable gas S-19 is throttled and expanded by the throttling expansion valve 97, and the throttled gas S-20 is transported to the third inlet of the cold recovery unit 80, enters the cold recovery unit 80 to recover cold, and the cold recovered gas S-21 is output from the second outlet of the cold recovery unit 80, and merges with the raw gas S-5 after compression heat regeneration, drying and dehydration to form the gas to be adsorbed S-6, and enters the vacuum pressure swing adsorption unit 50 to adsorb CO2.

[0066] According to calculations, the use of the carbon dioxide adsorption system of the present invention for CO2 capture and liquefaction can achieve a capture energy consumption of about 300-400kW / t CO2, a liquefaction energy consumption of about 150-200kW / t CO2, and a capture cost of about 180-240 yuan / t, a liquefaction cost of about 90-120 yuan / t, and a total of about 270-360 yuan / t CO2 based on an electricity price of 0.6 yuan / kW. The equivalent energy consumption index is about 1.1-1.5GJ / t CO2 for capture, about 0.54-0.72GJ / t CO2 for liquefaction, and about 1.64-2.22GJ / t in total, which is significantly better than the equivalent energy consumption index of 3.0-4.0GJ / tCO2 and the comprehensive capture and liquefaction cost of 400-500 yuan / t CO2 of conventional processes.

[0067] The advantages of the carbon dioxide adsorption system of the present invention are explained below in combination with two experimental cases.

[0068] Case 1:

[0069] In this case, the flue gas of a coal boiler of a certain enterprise is about 60000Nm3 / h, the pressure is about 20kPag, the temperature is about 50℃, and the components are: 75.51% N2, 5.1% O2, 12.24% CO2 and 7.14% H2O. The carbon dioxide adsorption system of the present invention is compared with the traditional chemical absorption method and low-pressure adsorption method, as shown in the following table.

[0070] project unit Chemical absorption method Low pressure adsorption method The present invention <![CDATA[Liquid CO2 production]]> t / h 12.28 12.28 12.28 Capture power consumption kW 1093 5194 4395 Capture steam consumption t / h 14.7 0 0 Liquefaction power consumption kW 2326 2908 1998 Liquefaction steam consumption t / h 2.5 0 0 Electricity Prices Yuan / kW 0.6 0.6 0.6 Steam Prices Yuan / t 200 200 200 Capture equivalent energy consumption <![CDATA[GJ / tCO2]]> 3.00 1.52 1.29 Liquefaction equivalent energy consumption <![CDATA[GJ / tCO2]]> 1.14 0.85 0.59 Capture cost <![CDATA[Yuan / tCO2]]> 293.4 253.8 214.7 Liquefaction costs <![CDATA[Yuan / tCO2]]> 154.4 142.1 97.6 Total equivalent energy consumption <![CDATA[GJ / tCO2]]> 4.14 2.38 1.87 Total cost <![CDATA[Yuan / tCO2]]> 447.8 395.9 312.4

[0071] It can be seen from this case that the carbon dioxide adsorption system of the present invention has the lowest equivalent energy consumption and cost for CO2 capture and liquefaction of flue gas, which are 1.87 GJ / tCO2 and 312.4 yuan / tCO2, respectively, which are significantly better than the chemical absorption method (4.14 GJ / tCO2 and 447.8 yuan / tCO2, respectively) and the low-pressure adsorption method (2.38 GJ / tCO2 and 395.9 yuan / tCO2, respectively), and the energy-saving benefit is remarkable.

[0072] Case 2:

[0073] In this case, the flue gas of a natural gas boiler of a certain enterprise is about 88000Nm3 / h, the pressure is about 30kPag, the temperature is about 120℃, and the components are: 77.77% N2, 2.37% O2, 10.3% CO2 and 9.56% H2O. The carbon dioxide adsorption system of the present invention is compared with the traditional chemical absorption method and low-pressure adsorption method, as shown in the following table.

[0074]

[0075]

[0076] From this case, it can be seen that the carbon dioxide adsorption system of the present invention has the lowest equivalent energy consumption and cost for CO2 capture and liquefaction of flue gas, which are 1.97 GJ / tCO2 and 328.5 yuan / tCO2, respectively, which are significantly better than the chemical absorption method (4.11 GJ / tCO2 and 440.3 yuan / tCO2, respectively) and the low-pressure adsorption method (2.45 GJ / tCO2 and 407.9 yuan / tCO2, respectively) systems, and the energy-saving benefits are significant.

[0077] In summary, the carbon dioxide adsorption system of the present invention can effectively improve the carbon dioxide capture efficiency, reduce the equipment size, and reduce the energy consumption of carbon dioxide capture and liquefaction, simplify the process flow, is suitable for large-scale application, and achieves energy conservation and environmental protection.

[0078] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A carbon dioxide adsorption system, It is characterized in that include: A first compressor unit, wherein the inlet of the first compressor unit is connected to the raw gas inlet, and the pressure of the outlet of the first compressor unit is 0.9 MPag~2.0 MPag; A temperature swing adsorption unit, wherein the outlet of the first compressor unit is connected to the inlet of the temperature swing adsorption unit; The vacuum pressure swing adsorption unit, the outlet of the temperature swing adsorption unit is connected to the inlet of the vacuum pressure swing adsorption unit, the first outlet of the vacuum pressure swing adsorption unit discharges non-adsorbed gas and the second outlet discharges CO 2 Desorbed gas with a volume content higher than 90%; a turbine expansion unit, wherein the first outlet of the vacuum pressure swing adsorption unit is connected to the inlet of the turbine expansion unit, the turbine expansion unit is connected to the first compressor unit, the turbine expansion unit performs turbine expansion on the non-adsorbed gas discharged from the vacuum pressure swing adsorption unit, and uses the gas after turbine expansion to drive the first compressor unit to pressurize the raw gas; a third compressor unit, wherein the inlet of the third compressor unit is connected to the second outlet of the vacuum pressure swing adsorption unit, and the temperature of the outlet of the third compressor unit is 30° C. to 50° C.; A cold recovery unit, wherein the outlet of the turbine expansion unit is connected to the first inlet of the cold recovery unit, the outlet of the third compressor unit is connected to the second inlet of the cold recovery unit, the temperature of the first outlet and the second outlet of the cold recovery unit is -20°C to -60°C, and the cold recovery unit is also provided with a decarbonation raw material outlet; A first separator, wherein the first outlet of the cold recovery unit is connected to the inlet of the first separator, the first outlet of the first separator is connected to the third inlet of the cold recovery unit via a throttling expansion valve, so that the cold recovery unit can recover the cold after throttling expansion, the temperature range of the cold after throttling expansion is -50°C to -90°C, the second outlet of the cold recovery unit is connected to the inlet of the vacuum pressure swing adsorption unit, and the second outlet of the first separator is connected to the carbon dioxide liquid outlet; The cold energy recovery unit recovers the cold energy after turbine expansion of the turbine expansion unit and the cold energy after throttling expansion of the throttling expansion valve, and cools the gas pressurized by the third compressor unit.

2. The carbon dioxide adsorption system according to claim 1, Features: The temperature of the outlet of the first compressor unit is 100°C to 150°C; The dew point temperature at the outlet of the temperature swing adsorption unit is -30°C to -60°C; The pressure at the first outlet of the vacuum pressure swing adsorption unit is 0.4MPag~2.0MPag and the temperature is 20℃~40℃; The outlet pressure of the turbine expansion unit is 0.01 MPag~0.05 MPag, and the temperature is -40°C~-70°C.

3. The carbon dioxide adsorption system according to claim 1, It is characterized in that The adsorbent in the temperature swing adsorption unit is a combination of one or more of alumina, activated carbon, silica gel, molecular sieve and MOFs adsorbent; The adsorbent in the vacuum pressure swing adsorption unit is a combination of one or more of alumina, activated carbon, silica gel, molecular sieve and MOFs adsorbent.

4. The carbon dioxide adsorption system according to claim 1, It is characterized in that Also includes: a second compressor unit connected between the raw gas inlet and the inlet of the first compressor unit; The pressure at the outlet of the second compressor unit is 0.2MPag~1.0MPag, and the temperature is 30℃~50℃.

5. The carbon dioxide adsorption system according to claim 4, It is characterized in that Also includes: a washing and cooling unit connected between the raw gas inlet and the inlet of the second compressor unit; Wherein, the temperature of the outlet of the washing and cooling unit is 30°C~50°C.

6. The carbon dioxide adsorption system according to claim 1, It is characterized in that Also includes: A vacuum pump is connected between the second outlet of the vacuum pressure swing adsorption unit and the second inlet of the cold recovery unit.

7. The carbon dioxide adsorption system according to claim 1, It is characterized in that The outlet pressure of the third compressor unit is 3.5 MPag~8.0 MPag.

8. The carbon dioxide adsorption system according to claim 1, It is characterized in that Also includes: The second separator, the first outlet of the first separator is connected to the inlet of the second separator, the first outlet of the second separator is connected to the third inlet of the cold recovery unit through the throttling expansion valve, and the second outlet of the second separator is connected to the carbon dioxide liquid outlet.

9. The carbon dioxide adsorption system according to claim 8, It is characterized in that Also includes: a condenser connected between the first outlet of the first separator and the inlet of the second separator; Wherein, the temperature of the outlet of the condenser is -30°C~-70°C.

10. The carbon dioxide adsorption system according to any one of claims 1 to 9, It is characterized in that The raw gas introduced into the raw gas inlet is boiler flue gas, catalytic coking flue gas, hydrogen production cracking furnace flue gas or industrial furnace flue gas.

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