Method and system for capturing carbon dioxide from power plant boiler flue gas

Abstract

The present invention provides a method for capturing carbon dioxide from flue gas of power plant boilers, comprising: (1) introducing the flue gas of power plant boilers into a high-temperature activation furnace, and performing a primary carbonization activation on the raw materials for producing carbon-based adsorption materials therein as a protective atmosphere and a partial activation medium, thereby obtaining a primary carbonized activated material; wherein the raw materials for producing carbon-based adsorption materials include coal; (2) introducing an activation medium into the high-temperature activation furnace to perform a deep activation on the obtained primary carbonized activated material, thereby obtaining a carbon-based adsorption material; (3) sending the obtained carbon-based adsorption material to an adsorption carbon dioxide capture unit for use as an adsorption material, and sending the tail gas of the high-temperature activation furnace to the unit for carbon dioxide adsorption capture after denitration, dust removal and desulfurization in turn, thereby outputting a carbon dioxide product gas. A system for capturing carbon dioxide from flue gas of power plant boilers in the aforementioned method is also provided. The method and system can achieve the capture of CO in flue gas of power plant boilers. 2 Low energy consumption and low cost capture.

Description

Technical Field

[0001] The present invention belongs to the field of carbon dioxide capture, and in particular relates to a method and a system for capturing carbon dioxide from flue gas of a power plant boiler. Background Art

[0002] At present, coal-fired power has become a key area for the application of CCUS technology. Among the three mainstream carbon capture technologies, solvent, adsorption and membrane, adsorption carbon capture technology is considered to have the most potential for development due to its large potential for energy consumption and comprehensive cost reduction, environmental friendliness, and low equipment corrosion. However, the high energy consumption and cost of CO2 capture are still the main bottlenecks restricting the large-scale application and promotion of this technology.

[0003] The development of low-cost carbon capture materials and processes is the key to reducing the cost of carbon capture by adsorption. Carbon-based adsorption materials are very suitable for large-scale carbon capture because they have a large specific surface area, a developed pore structure, and are low in price, simple to prepare, and have good stability. CN 116726897 A discloses an activated carbon adsorbent and its preparation method and application. The patent pre-treats the material and the activator and mixes them evenly. The material is first pyrolyzed in a N2 atmosphere, then carbonized, and then cooled, ground, washed, and dried to obtain the activated carbon adsorbent. However, this technology and many existing carbon-based adsorption materials use nitrogen as a protective atmosphere to pyrolyze or carbonize the material during the preparation process, which consumes a large amount of nitrogen, and the heating process is generally high temperature, resulting in high production costs. In addition, the exhaust gas after pyrolysis also needs to be treated with desulfurization, denitrification, and dust removal to meet the emission standards, which will also increase the production cost of the material. In the adsorption carbon capture process, its energy consumption mainly comes from the power consumption of large-scale dynamic equipment such as fans / vacuum pumps. The electricity mainly comes from steam power generation, which has low power generation efficiency. If the energy utilization efficiency can be improved from the source, the energy consumption of the equipment can be further reduced, thereby reducing the capture cost. However, there is currently no method reported to solve the above technical problems. Summary of the invention

[0004] The first object of the present invention is to provide a method for capturing carbon dioxide from flue gas of power plant boilers, which method can achieve efficient utilization of the flue gas of power plant boilers and low-cost capture of carbon dioxide therein.

[0005] The second object of the present invention is to provide a system for capturing carbon dioxide from power plant boiler flue gas in the aforementioned method, which system can achieve efficient utilization of the plant boiler flue gas and low-cost capture of carbon dioxide therein.

[0006] To achieve the first object of the present invention, the following technical solutions are adopted:

[0007] A method for capturing carbon dioxide from flue gas of a power plant boiler comprises the following steps:

[0008] (1) introducing the boiler flue gas of a power plant generated by the mixed combustion of coal and air in a power plant boiler into a high-temperature activation furnace, and performing a primary carbonization activation on the raw materials used to produce the carbon-based adsorption material therein as a protective atmosphere and a partial activation medium, thereby obtaining a primary carbonized activated material;

[0009] (2) introducing an activation medium into the high-temperature activation furnace to deeply activate the primary carbonized activated material obtained in step (1) to obtain a carbon-based adsorption material;

[0010] (3) sending the carbon-based adsorption material obtained in step (2) to an adsorption carbon dioxide capture unit for use as an adsorption material, and sending the tail gas of the high-temperature activation furnace to the unit for carbon dioxide adsorption capture after denitration, dust removal and desulfurization, and outputting carbon dioxide product gas and decarbonized gas for discharge; wherein,

[0011] In step (1), the raw material used to produce the carbon-based adsorbent material includes coal;

[0012] In step (3), the high-temperature activation furnace tail gas refers to the tail gas generated during the preparation of the carbon-based adsorption material.

[0013] In the method for capturing carbon dioxide from flue gas in power plant boilers of the present invention, preferably, in step (1), the raw material for producing the carbon-based adsorption material also includes an activator.

[0014] The method for capturing carbon dioxide from flue gas of a power plant boiler of the present invention preferably comprises, in step (1), the activator in the raw material for producing the carbon-based adsorption material is a combination of any one or more of KOH, KNO3 and K2CO3.

[0015] The method for capturing carbon dioxide from flue gas of a power plant boiler of the present invention preferably comprises, in step (1), in the raw material for producing the carbon-based adsorption material, a mass ratio of the activator to the coal is (0.01-1):1.

[0016] The method for capturing carbon dioxide from flue gas from power plant boilers of the present invention preferably comprises the following steps: in step (1), the temperature of the flue gas from the power plant boilers is 800-1100°C.

[0017] The method for capturing carbon dioxide from flue gas of a power plant boiler of the present invention preferably comprises the following steps: in step (1), the time for a single carbonization activation is 1 to 4 hours.

[0018] The method for capturing carbon dioxide from flue gas of a power plant boiler of the present invention is preferably such that in step (2), the time for deep activation is 0.5 to 3 hours.

[0019] The method for capturing carbon dioxide from flue gas of power plant boilers of the present invention is preferably such that in step (2), the activation medium introduced into the high-temperature activation furnace is any one or more of a combination of water vapor, air and CO2, preferably CO2.

[0020] In the method for capturing carbon dioxide from flue gas of a power plant boiler of the present invention, preferably, the CO2 as an activation medium introduced into the high-temperature activation furnace comes from the carbon dioxide product gas output from step (3).

[0021] The method for capturing carbon dioxide from flue gas in power plant boilers of the present invention preferably further comprises step (4), wherein heat generated by the mixed combustion of coal and air in the power plant boiler is sent to a power generation unit to generate power plant steam, and the generated power plant steam is then sent to a moving device in the adsorption carbon dioxide capture unit to replace electrical energy to drive its operation.

[0022] To achieve the second object of the present invention, a system for capturing carbon dioxide from flue gas of a power plant boiler in the aforementioned method is provided, the system comprising a power plant boiler, a high temperature activation furnace, a denitrification device, a dust removal device, a desulfurization device, an adsorption carbon dioxide capture unit and a power plant chimney which are sequentially connected through pipelines; wherein,

[0023] The power plant boiler is used to produce power plant boiler flue gas and heat by using the mixed combustion of coal and air;

[0024] The high-temperature activation furnace comprises a flue gas inlet, a coal inlet, an activation medium inlet, a carbon-based adsorption material product outlet and a tail gas outlet, and is connected to the flue gas outlet of the power plant boiler of the power plant boiler through its flue gas inlet, feeds coal through its coal inlet, introduces activation medium through its activation medium inlet, is connected to the adsorption tower of the adsorption carbon dioxide capture unit through its carbon-based adsorption material product outlet, and outputs the tail gas of the high-temperature activation furnace through its tail gas outlet;

[0025] The denitration equipment, the dust removal equipment, and the desulfurization equipment are used to sequentially perform denitration, dust removal, and desulfurization on the introduced flue gas materials; wherein the flue gas materials include the high-temperature activation furnace tail gas from the high-temperature activation furnace 2;

[0026] The adsorption carbon dioxide capture unit includes a pressurized fan, an adsorption tower, a vacuum pump and a carbon dioxide product gas storage tank; one end of the pressurized fan is connected to the outlet of the desulfurization equipment, and the other end is connected to the bottom inlet of the adsorption tower, for introducing the gas from the desulfurization equipment; the inlet and outlet of the vacuum pump are respectively connected to the bottom outlet of the adsorption tower and the inlet of the carbon dioxide product gas storage tank, and the top outlet of the adsorption tower is connected to the chimney of the power plant, for adsorbing and capturing carbon dioxide on the introduced gas, outputting the decarbonized gas to the chimney of the power plant for discharge, and outputting the carbon dioxide product gas to the carbon dioxide product gas storage tank for storage.

[0027] In the system of the present invention, preferably, the high-temperature activation furnace is connected to the outlet of the carbon dioxide product gas storage tank through its activation medium inlet, so as to return the carbon dioxide from the carbon dioxide product gas storage tank to the high-temperature activation furnace for use as an activation medium.

[0028] In the system of the present invention, preferably, in the adsorption carbon dioxide capture unit, there are 3 to 12 adsorption towers, which are arranged in parallel.

[0029] The system of the present invention preferably further comprises a power generation unit, one end of which is connected to the power plant boiler, and the other end of which is connected to the moving equipment in the adsorption carbon dioxide capture unit, for introducing and utilizing the heat generated by the mixed combustion of coal and air in the power plant boiler to generate power plant steam, and utilizing the generated power plant steam instead of electrical energy to drive the moving equipment in the adsorption carbon dioxide capture unit to operate.

[0030] The beneficial effects of the present invention are:

[0031] (1) The method and system for capturing carbon dioxide from power plant boiler flue gas of the present invention utilizes power plant boiler flue gas (power plant boiler flue gas is generally composed of more than 70 vol% N2, 12-15 vol% CO2, 5-8 vol% H2O, 5-7 vol% O2 and a small amount of gas impurities) generated by the mixed combustion of coal and air in the power plant boiler to replace nitrogen as a protective gas to perform high-temperature carbonization activation on the raw materials for producing carbon-based adsorption materials. This not only saves nitrogen consumption, but also directly utilizes the heat of the flue gas to carbonize and activate the raw materials for producing carbon-based adsorption materials, greatly saving the cost of electric heating. At the same time, a certain amount of CO2 and H2O in the power plant boiler flue gas can also be used as an activation medium to produce a certain activation effect on the raw materials for producing carbon-based adsorption materials under high temperature conditions, thereby saving a large amount of production costs while also being beneficial to improving the adsorption performance of the obtained carbon-based adsorption materials.

[0032] (2) The method and system for capturing carbon dioxide from boiler flue gas in a power plant of the present invention can use the waste gas (i.e., high-temperature activation furnace tail gas) generated during the roasting process of the raw materials for producing carbon-based adsorption materials in a high-temperature activation furnace to share the power plant's tail gas treatment equipment such as denitrification, desulfurization, and dust removal, and does not need to be separately treated to meet emission standards, further reducing the production cost of the material.

[0033] (3) The method and system for capturing carbon dioxide from power plant boiler flue gas of the present invention, the carbon-based adsorption material obtained by high-temperature roasting can be directly used as the adsorption material of the adsorption tower in the adsorption method carbon dioxide capture unit to capture CO2 in the power plant boiler flue gas, specifically, the CO2 is captured from the power plant boiler flue gas or the flue gas of the high-temperature activation furnace after denitrification, dust removal and desulfurization in sequence, and the captured CO2 can be used as a part of the activation medium to participate in the preparation of the carbon-based adsorption material, thereby achieving efficient utilization of CO2 product gas while reducing carbon; and the high-pressure power plant steam generated by the power plant power generation unit can directly replace electrical energy to drive the operation of the booster fan and / or vacuum pump and other dynamic equipment in the adsorption method carbon capture unit, thereby improving the energy utilization efficiency from the source and greatly reducing the energy consumption and cost of capturing carbon dioxide from power plant boiler flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic structural diagram of a system for capturing carbon dioxide from flue gas of a power plant boiler according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the system used for capturing carbon dioxide from power plant boiler flue gas in Example 1. DETAILED DESCRIPTION

[0036] The technical scheme and its effects of the present invention are further described below in conjunction with specific implementation methods / examples. The following implementation methods / examples are only used to illustrate the content of the present invention, and the invention is not limited to the following implementation methods or examples. Simple changes made to the present invention using the concept of the present invention are all within the scope of protection claimed by the present invention.

[0037] like Figure 1 As shown, a method for capturing carbon dioxide from flue gas of a power plant boiler comprises the following steps:

[0038] (1) introducing the boiler flue gas of a power plant generated by the mixed combustion of coal and air in a power plant boiler into a high-temperature activation furnace, and performing a primary carbonization activation on the raw materials used to produce the carbon-based adsorption material therein as a protective atmosphere and a partial activation medium, thereby obtaining a primary carbonized activated material;

[0039] (2) introducing an activation medium into the high-temperature activation furnace to deeply activate the primary carbonized activated material obtained in step (1) to obtain a carbon-based adsorption material;

[0040] (3) sending the carbon-based adsorption material obtained in step (2) to an adsorption carbon dioxide capture unit for use as an adsorption material, and sending the tail gas of the high-temperature activation furnace to the unit for carbon dioxide adsorption capture after denitration, dust removal and desulfurization, and outputting carbon dioxide product gas and decarbonized gas for discharge; wherein,

[0041] In step (1), the raw material used to produce the carbon-based adsorbent material includes coal;

[0042] In step (3), the high-temperature activation furnace tail gas refers to the tail gas generated during the preparation of the carbon-based adsorption material.

[0043] Those skilled in the art understand that the flue gas produced by the mixed combustion of coal and air in a power plant boiler generally consists of more than 70 vol% N2, 12-15 vol% CO2, 5-8 vol% H2O, 5-7 vol% O2 and a small amount of gas impurities.

[0044] Those skilled in the art understand that, currently, when producing carbon-based adsorbent materials, nitrogen is generally used as a protective gas, and an activation medium is introduced to perform high-temperature carbonization activation on the raw materials used to produce the carbon-based adsorbent materials to prepare the carbon-based adsorbent materials. The nitrogen also needs to be preheated to the corresponding carbonization activation temperature, which not only consumes a large amount of nitrogen, but also consumes heating energy. The method for capturing carbon dioxide from power plant boiler flue gas of the present invention utilizes the power plant boiler flue gas generated by the mixed combustion of coal and air in the power plant boiler instead of nitrogen as a protective gas to perform high-temperature carbonization activation on the raw materials used to produce carbon-based adsorbent materials. This not only saves nitrogen consumption, but also directly utilizes the heat of the flue gas to perform carbonization activation on the raw materials used to produce carbon-based adsorbent materials, greatly saving the cost of electric heating; at the same time, a certain amount of CO2 and H2O in the power plant boiler flue gas can also be used as an activation medium to produce a certain activation effect on the raw materials used to produce carbon-based adsorbent materials under a high temperature environment, thereby saving a large amount of production costs while also having It is beneficial to improve the adsorption performance of the prepared carbon-based adsorption material; and the waste gas generated during the roasting process of the raw materials used to produce the carbon-based adsorption material in the high-temperature activation furnace (i.e., the high-temperature activation furnace tail gas) can share the power plant's denitrification, desulfurization, dust removal and other tail gas treatment equipment, and does not need to be separately treated to meet emission standards, further reducing the production cost of the material; in addition, the carbon-based adsorption material obtained by high-temperature roasting can be directly used as the adsorption material of the adsorption tower in the adsorption method carbon dioxide capture unit to capture CO2 in the power plant boiler flue gas, specifically, to capture CO2 from the power plant boiler flue gas or the high-temperature activation furnace tail gas after denitrification, dust removal and desulfurization.

[0045] In order to improve the activation effect, in one embodiment, in step (1), the raw material for producing the carbon-based adsorption material also includes an activator; preferably, in step (1), in the raw material for producing the carbon-based adsorption material, the mass ratio of the activator to the coal is (0.01-1):1, such as 0.02:1, 0.05:1, 0.1:1, 0.3:1, 0.6:1, 0.8:1 and 1:1.

[0046] In one embodiment, in step (1), in the raw material for producing the carbon-based adsorption material, the activating agent is a combination of any one or more of KOH, KNO3 and K2CO3.

[0047] In one embodiment, in step (1), the temperature of the flue gas from the power plant boiler is 800-1100°C, such as 850°C, 900°C, 950°C, 1000°C and 1050°C.

[0048] In order to improve the activation effect, in one embodiment, in step (1), the time of one carbonization activation is 1 to 4 hours, such as 1 hour, 2 hours, 2.5 hours, 3 hours and 3.5 hours.

[0049] In order to improve the pore-forming effect, in one embodiment, in step (2), the time of deep activation is 0.5 to 3 h, such as 0.5 h, 1 h, 2 h and 2.5 h.

[0050] In one embodiment, in step (2), the activation medium introduced into the high-temperature activation furnace is a combination of any one or more of water vapor, air and CO2, preferably CO2; preferably, the CO2 introduced into the high-temperature activation furnace as the activation medium comes from the carbon dioxide product gas output from step (3), so that the CO2 captured by the adsorption carbon dioxide capture unit is also used as a part of the activation medium to participate in the preparation of the carbon-based adsorption material, thereby achieving efficient utilization of the CO2 product gas while reducing carbon.

[0051] In one embodiment, in step (3), the adsorption pressure of the adsorption carbon dioxide capture unit is 0.1-1 MPa (A), such as 0.2 MPa (A), 0.3 MPa (A), 0.4 MPa (A), 0.5 MPa (A), 0.6 MPa (A), 0.7 MPa (A), 0.8 MPa (A) and 0.9 MPa (A); and / or the adsorption temperature is -20-30 ° C, such as -15 ° C, - 10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C and 25°C; and / or the desorption pressure is 0 to 0.1MPa(A), such as 0.01MPa(A), 0.02MPa(A), 0.03MPa(A), 0.04MPa(A), 0.05MPa(A), 0.06MPa(A), 0.07MPa(A), 0.08MPa(A) and 0.09MPa(A).

[0052] In one embodiment, the method further includes step (4), wherein the heat generated by the mixed combustion of coal and air in the power plant boiler is sent to the power generation unit to generate power plant steam, and then the generated power plant steam is sent to the dynamic equipment (such as a booster fan, a vacuum pump) in the adsorption carbon dioxide capture unit to replace electrical energy to drive its operation, thereby improving the energy utilization efficiency from the source and greatly reducing the energy consumption and cost of capturing carbon dioxide from the flue gas of the power plant boiler.

[0053] Those skilled in the art understand that the power plant steam generated by the power generation unit is high-pressure steam.

[0054] In one embodiment, the method further includes: adjusting the air intake of the power plant boiler flue gas to the high-temperature activation furnace according to the production demand of the carbon-based adsorption material, and directly sending the excess power plant boiler flue gas to the adsorption carbon dioxide capture unit for carbon dioxide adsorption capture after denitrification, dust removal and desulfurization.

[0055] The present invention also provides a system for capturing carbon dioxide from flue gas of a power plant boiler in the above method, such as Figure 1 As shown, the system includes a power plant boiler 1, a high temperature activation furnace 2, a denitrification device 3, a dust removal device 4, a desulfurization device 5, an adsorption carbon dioxide capture unit 6 and a power plant chimney 8 which are sequentially connected through pipelines; wherein,

[0056] The power plant boiler 1 is used to produce power plant boiler flue gas and heat by using the mixed combustion of coal and air;

[0057] The high-temperature activation furnace 2 comprises a flue gas inlet, a coal inlet, an activation medium inlet, a carbon-based adsorption material product outlet and a tail gas outlet, and is connected to the flue gas outlet of the power plant boiler 1 through its flue gas inlet, feeds coal through its coal inlet, introduces activation medium through its activation medium inlet, is connected to the adsorption tower 62 of the adsorption carbon dioxide capture unit 6 through its carbon-based adsorption material product outlet, and outputs the high-temperature activation furnace tail gas through its tail gas outlet;

[0058] The denitration equipment 3, the dust removal equipment 4, and the desulfurization equipment 5 are used to sequentially perform denitration, dust removal, and desulfurization on the introduced flue gas materials; wherein the flue gas materials include the high-temperature activation furnace tail gas from the high-temperature activation furnace 2;

[0059] The adsorption carbon dioxide capture unit 6 includes a pressurized fan 61, an adsorption tower 62, a vacuum pump 63 and a carbon dioxide product gas storage tank 64; one end of the pressurized fan 61 is connected to the outlet of the desulfurization equipment 5, and the other end is connected to the bottom inlet of the adsorption tower 62, for introducing the gas from the desulfurization equipment 5; the inlet and outlet of the vacuum pump 63 are respectively connected to the bottom outlet of the adsorption tower 62 and the inlet of the carbon dioxide product gas storage tank 64, and the top outlet of the adsorption tower 62 is connected to the power plant chimney 8, for adsorbing and capturing carbon dioxide on the introduced gas, outputting the decarbonized gas to the power plant chimney 8 for discharge, and outputting the carbon dioxide product gas to the carbon dioxide product gas storage tank 64 for storage.

[0060] In one embodiment, the high-temperature activation furnace 2 is connected to the outlet of the carbon dioxide product gas storage tank 64 through its activation medium inlet, and is used to return the carbon dioxide from the carbon dioxide product gas storage tank 64 to the high-temperature activation furnace 2 for use as an activation medium, thereby participating in the preparation of carbon-based adsorption materials, and achieving efficient utilization of CO2 product gas while reducing carbon.

[0061] In one embodiment, in the adsorption carbon dioxide capture unit 6, there are 3-12 adsorption towers 62, such as 3, 6, 9 and 12, which are arranged in parallel, so that the adsorption carbon dioxide capture unit 6 can simultaneously adsorb and desorb CO2, maintain the continuous operation of the adsorption carbon dioxide capture unit 6, and further maintain the continuous operation of the entire system.

[0062] In one embodiment, the system further includes a power generation unit 7, one end of which is connected to the power plant boiler 1, and the other end of which is connected to the dynamic equipment in the adsorption carbon dioxide capture unit 6, for introducing and utilizing the heat generated by the mixed combustion of coal and air in the power plant boiler 1 to generate power plant steam, and utilizing the generated power plant steam instead of electrical energy to drive the dynamic equipment (such as the booster fan 61 and / or the vacuum pump 63) in the adsorption carbon dioxide capture unit 6.

[0063] In one embodiment, in the system, a flue gas pipeline is further provided from the outlet of the power plant boiler 1 to the inlet of the denitrification equipment 3, for directly delivering the power plant boiler flue gas from the power plant boiler 1 to the denitrification equipment 3, and directly delivering the excess power plant boiler flue gas during the production of carbon-based adsorption materials to the adsorption carbon dioxide capture unit for carbon dioxide adsorption capture after denitrification and subsequent dust removal and desulfurization.

[0064] Those skilled in the art will appreciate that, at this time, the flue gas material introduced into the denitration device (3) includes the power plant boiler flue gas from the power plant boiler 1.

[0065] The method and system for capturing carbon dioxide from power plant boiler flue gas of the present invention utilizes the power plant boiler flue gas generated by the mixed combustion of coal and air in the power plant boiler instead of nitrogen as a protective gas to perform high-temperature carbonization activation on the raw materials for producing carbon-based adsorption materials, which not only saves the consumption of nitrogen, but also can directly utilize the heat of the flue gas to perform carbonization activation on the raw materials for producing carbon-based adsorption materials, greatly saving the cost of electric heating; at the same time, a certain amount of CO2 and H2O in the power plant boiler flue gas can also be used as an activation medium to produce a certain activation effect on the raw materials for producing carbon-based adsorption materials under a high-temperature environment, thereby saving a large amount of production costs while also being beneficial to improving the adsorption performance of the obtained carbon-based adsorption materials; and the waste gas (i.e., the high-temperature activation furnace tail gas) generated during the roasting process of the raw materials for producing carbon-based adsorption materials in the high-temperature activation furnace can share the denitrification of the power plant. , dust removal, desulfurization and other tail gas treatment devices, there is no need to carry out separate emission treatment to meet the standards, which further reduces the production cost of the material; in addition, the carbon-based adsorption material obtained by high-temperature calcination can be directly used as the adsorption material of the adsorption tower in the adsorption method carbon dioxide capture unit to capture CO2 in the power plant boiler flue gas. Specifically, the CO2 is captured from the power plant boiler flue gas or the high-temperature activation furnace tail gas after denitrification, dust removal and desulfurization. The captured CO2 can be used as a partial activation medium to participate in the preparation of carbon-based adsorption materials, thereby achieving efficient utilization of CO2 product gas while reducing carbon; and the high-pressure power plant steam generated by the power plant power generation unit can directly replace electrical energy to drive the operation of dynamic equipment such as the booster fan and / or vacuum pump in the adsorption method carbon capture unit, thereby improving the energy utilization efficiency from the source and greatly reducing the energy consumption and cost of carbon dioxide capture in the power plant boiler flue gas.

[0066] The present invention is further described below by means of specific examples.

[0067] In the following examples and comparative examples, the sources of the raw materials used are as follows:

[0068] Coal, Xinjiang coal;

[0069] KOH was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0070] KNO3 was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0071] K2CO3 was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0072] Commercially available CO2 gas, 99.99 vol%.

[0073] The test methods for relevant parameters are as follows:

[0074] The specific surface area of ​​the obtained carbon-based adsorbent material was measured by using a Micromeritics ASAP 2460 gas adsorption instrument produced by Micromeritics Instruments (USA) at 77K. The sample was degassed at 300°C for 4 hours. The surface area was calculated by the Brunauer-Emmett-Teller (BET) method in the relative pressure range of P / P0 = 0.015 to 0.3 according to the recommendations of IUPAC.

[0075] Adsorption capacity of the obtained carbon-based adsorbent material: The adsorption capacity of the obtained carbon-based adsorbent material sample was measured using a STA 449F3 synchronous thermal analyzer produced by NETZSCH, Germany. The test conditions were as follows: the obtained carbon-based adsorbent material sample was pretreated at a constant temperature of 300°C in N2 for 30 minutes to remove any physically adsorbed impurities such as H2O and / or CO2. After the temperature was cooled and stabilized at 40°C, it was switched to the adsorption object (i.e., the inlet flue gas of the adsorption carbon dioxide capture unit 6), and its adsorption capacity was calculated by weight gain (those skilled in the art will understand that the adsorption capacity refers to the saturated adsorption capacity under the test conditions).

[0076] Example 1 (S1)

[0077] Use Figure 1 The system and method shown are used to capture carbon dioxide from flue gas of a power plant boiler, and specifically include the following steps:

[0078] (1) The power plant boiler flue gas (800° C.) generated by the mixed combustion of coal and air in the power plant boiler 1 is introduced into the high-temperature activation furnace 2, and the raw materials used for producing carbon-based adsorption materials therein are carbonized and activated as a protective atmosphere and a part of the activation medium to obtain a primary carbonized activated material;

[0079] (2) introducing an activation medium into the high-temperature activation furnace 2 to deeply activate the primary carbonized activated material obtained in step (1) to obtain a carbon-based adsorption material;

[0080] (3) The carbon-based adsorption material obtained in step (2) is sent to the adsorption carbon dioxide capture unit 6, and then sent to the adsorption tower 62 therein for use as adsorption material, and the high-temperature activation furnace tail gas is sequentially denitrated, dusted and desulfurized by the denitration equipment 3, the dust removal equipment 4 and the desulfurization equipment 5, and then sent to the denitration equipment 3, the dust removal equipment 4 and the desulfurization equipment 5 through the internal pressure fan 61 for carbon dioxide adsorption capture, and the carbon dioxide product gas is output to the carbon dioxide product gas storage tank 64 through the vacuum pump 63, and the decarbonized gas is discharged through the chimney 8 of the power plant;

[0081] (4) The heat generated by the combustion of coal and air in the power plant boiler is sent to the power generation unit to generate power plant steam, and then the generated power plant steam is sent to the dynamic equipment in the adsorption carbon dioxide capture unit to replace electrical energy to drive its operation; wherein,

[0082] In step (1), the raw materials for producing the carbon-based adsorption material include coal and an activator, wherein the activator is KOH and KNO3; and the mass ratio of coal, KOH and KNO3 is 1:0.5:0.3; and the time for one carbonization activation is 1 hour;

[0083] In step (2), the activation medium introduced into the high-temperature activation furnace is the carbon dioxide product gas output from the carbon dioxide product gas storage tank 64 in step (3); the deep activation time is 2 hours; and the specific surface area is 1560m 2 / g of carbon-based adsorbent material, its CO2 adsorption capacity is about 7.6wt%;

[0084] In step (3), the high-temperature activation furnace tail gas refers to the tail gas generated in the process of preparing the carbon-based adsorption material; in the adsorption carbon dioxide capture unit 6, there are 6 adsorption towers 62, which are arranged in parallel; the adsorption pressure of the adsorption carbon dioxide capture unit 6 is 0.15MPa(A), the adsorption temperature is 25°C, and the desorption pressure is 0.02MPa(A).

[0085] result:

[0086] In Example 1, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 17,800 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 228 / tCO2.

[0087] Embodiment 2 (S2)

[0088] The system and method of Example 1 are used to capture carbon dioxide from flue gas of a power plant boiler. Compared with Example 1, the only differences are as follows:

[0089] In step (2), the activation medium introduced into the high-temperature activation furnace is commercially available CO2;

[0090] The specific surface area is 1560m 2 / g of carbon-based adsorbent material, and its CO2 adsorption capacity is about 7.6wt%.

[0091] result:

[0092] In Example 2, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 18,600 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 231 / tCO2.

[0093] Embodiment 3 (S3)

[0094] The system and method of Example 1 are used to capture carbon dioxide from flue gas of a power plant boiler. Compared with Example 1, the only differences are as follows:

[0095] In step (4), the moving equipment in the adsorption carbon dioxide capture unit is driven by conventional electrical energy;

[0096] The specific surface area is 1560m 2 / g of carbon-based adsorbent material, and its CO2 adsorption capacity is about 7.6wt%.

[0097] result:

[0098] In Example 3, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel costs, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 18,200 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 302 / tCO2.

[0099] Embodiment 4 (S4)

[0100] The system and method of Example 1 are used to capture carbon dioxide from flue gas of a power plant boiler. Compared with Example 3, there are only the following differences:

[0101] In step (1), the temperature of the flue gas from the power plant boiler is 900° C.; the raw materials used to produce the carbon-based adsorption material include coal and an activator, wherein the activator is KOH; and the mass ratio of coal to KOH is 1:0.5; and the time for a single carbonization activation is 2 hours;

[0102] In step (2), the deep activation time is 0.5 h; the specific surface area obtained is 1892 m 2 / g of carbon-based adsorption material, and its CO2 adsorption capacity is about 6.8wt%.

[0103] result:

[0104] In Example 4, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 17,500 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 243 / tCO2.

[0105] Embodiment 5 (S5)

[0106] The system and method of Example 1 are used to capture carbon dioxide from flue gas of a power plant boiler. Compared with Example 1, the only differences are as follows:

[0107] In step (1), the temperature of the flue gas from the power plant boiler is 1100° C.; the raw materials used to produce the carbon-based adsorption material include coal and an activator, wherein the activator is K2CO3; and the mass ratio of coal to K2CO3 is 1:0.1; and the time for a carbonization activation is 4 hours;

[0108] In step (2), the deep activation time is 3 h; the specific surface area is 1785 m 2 / g of carbon-based adsorbent material, and its CO2 adsorption capacity is about 7.2wt%.

[0109] result:

[0110] In Example 5, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 17,000 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 240 / tCO2.

[0111] Embodiment 6 (S6)

[0112] The system and method of Example 1 are used to capture carbon dioxide from flue gas of a power plant boiler. Compared with Example 1, the only differences are as follows:

[0113] In step (1), the raw materials for producing the carbon-based adsorption material include coal and an activator, wherein the activator is K2CO3; and the mass ratio of coal to K2CO3 is 1:0.8;

[0114] The specific surface area is 1364m 2 / g of carbon-based adsorption material, and its CO2 adsorption capacity is about 6.9wt%.

[0115] result:

[0116] In Example 6, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 18,000 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 244 / tCO2.

[0117] Comparative Example 1 (D1)

[0118] like Figure 2 As shown, the carbon-based adsorption material is prepared according to the following method and carbon dioxide is captured from flue gas of a power plant boiler; the specific steps are as follows:

[0119] A mixture of coal, KOH and KNO3 in a mass ratio of 1:0.5:0.3 was used as the raw material for producing carbon-based adsorption materials. Nitrogen was used as the protective gas. After carbonization activation at 800°C for 1 hour in a high-temperature activation furnace, commercially available CO2 gas was introduced as the active medium for deep activation for 2 hours to form pores, and finally a specific surface area of ​​1200m 2 / g of carbon-based adsorption material, and the tail gas of the high-temperature activation furnace meets the emission standards after denitration, dust removal and desulfurization;

[0120] The obtained carbon-based adsorption material is used as an adsorption material in the adsorption tower in the adsorption carbon dioxide capture unit, and CO2 is captured from the flue gas of the power plant boiler after denitrification, dust removal and desulfurization, and the CO2 adsorption amount is about 6.3wt%; the adsorption carbon dioxide capture unit comprises 6 adsorption towers arranged in parallel, with an adsorption pressure of 0.15MPa(A), an adsorption temperature of 25°C, and a desorption pressure of 0.02MPa(A). The booster fan / vacuum pump and other dynamic equipment in the adsorption carbon dioxide capture unit are driven by conventional electricity.

[0121] result:

[0122] In Comparative Example 1, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials is approximately RMB 30,000 / ton, and the CO2 capture cost of power plant boiler flue gas is approximately RMB 326 / tCO2.

[0123] Comparison of results:

[0124] According to the comparison of the results of Examples 1-6 with Comparative Example 1, the method and system for capturing carbon dioxide from flue gas of power plant boilers of the present invention can not only reduce the production cost of carbon-based adsorption materials, but also reduce the cost of capturing CO2 from flue gas of power plant boilers;

[0125] Compared with Comparative Example 1, in Example 1, taking into account factors such as fixed investment, equipment depreciation, equipment maintenance, personnel expenses, capture power consumption and energy consumption, the production cost of carbon-based adsorption materials can be reduced by more than 40%, the specific surface area of ​​carbon-based adsorption materials is increased by more than 30%, and the CO2 adsorption amount is increased by about 20%. After calculation, a 40% reduction in the cost of carbon-based adsorption materials can reduce the CO2 capture cost by about 7%; in addition, by replacing electric drive with power plant steam drive for CO2 capture, the steam utilization efficiency is improved by more than 40%. After calculation, the capture cost can be reduced by more than 20%; based on the above, compared with Comparative Example 1, the method of Example 1 can reduce the CO2 capture cost by more than 27%.

Claims

1. A method for capturing carbon dioxide from flue gas of a power plant boiler, characterized in that: The method comprises the following steps: (1) introducing the boiler flue gas of a power plant generated by the mixed combustion of coal and air in a power plant boiler into a high-temperature activation furnace, and performing a primary carbonization activation on the raw materials used to produce the carbon-based adsorption material therein as a protective atmosphere and a partial activation medium, thereby obtaining a primary carbonized activated material; (2) introducing an activation medium into the high-temperature activation furnace to deeply activate the primary carbonized activated material obtained in step (1) to obtain a carbon-based adsorption material; (3) The carbon-based adsorption material obtained in step (2) is sent to an adsorption carbon dioxide capture unit for use as an adsorption material, and the tail gas of the high-temperature activation furnace is sent thereto for carbon dioxide adsorption capture after being subjected to denitration, dust removal and desulfurization in sequence, and the carbon dioxide product gas is output and returned to step (2) as an activation medium, and the decarbonized gas is discharged; The method further comprises step (4), wherein the heat generated by the combustion of the mixture of coal and air in the power plant boiler is sent to the power generation unit to generate power plant steam, and then the generated power plant steam is sent to the dynamic equipment in the adsorption carbon dioxide capture unit to replace the electric energy to drive its operation; wherein, In step (1), the raw material used to produce the carbon-based adsorbent material includes coal; In step (3), the high-temperature activation furnace tail gas refers to the tail gas generated during the preparation of the carbon-based adsorption material.

2. The method according to claim 1, characterized in that In step (1), the raw material for producing the carbon-based adsorption material also includes an activator.

3. The method according to claim 2, characterized in that In step (1), in the raw material for producing the carbon-based adsorption material, the activating agent is a combination of any one or more of KOH, KNO3 and K2CO3; and / or In step (1), in the raw material for producing the carbon-based adsorption material, the mass ratio of the activator to the coal is (0.01-1):

1.

4. The method according to any one of claims 1 to 3, characterized in that In step (1), the temperature of the flue gas from the power plant boiler is 800-1100° C.; and / or, In step (1), the time for one carbonization activation is 1 to 4 hours.

5. The method according to any one of claims 1 to 3, characterized in that: In step (2), the deep activation time is 0.5 to 3 hours.

6. A system for capturing carbon dioxide from flue gas of a power plant boiler in the method according to any one of claims 1 to 5, characterized in that: The system comprises a power plant boiler (1), a high temperature activation furnace (2), a denitration device (3), a dust removal device (4), a desulfurization device (5), an adsorption carbon dioxide capture unit (6) and a power plant chimney (8) which are sequentially connected through pipelines; wherein: The power plant boiler (1) is used to produce power plant boiler flue gas and heat by using a mixture of coal and air for combustion; The high-temperature activation furnace (2) comprises a flue gas inlet, a coal inlet, an activation medium inlet, a carbon-based adsorption material product outlet and a tail gas outlet, and is connected to the flue gas outlet of the power plant boiler (1) through its flue gas inlet, feeds coal through its coal inlet, introduces activation medium through its activation medium inlet, is connected to the adsorption tower (62) of the adsorption carbon dioxide capture unit (6) through its carbon-based adsorption material product outlet, and outputs the high-temperature activation furnace tail gas through its tail gas outlet; The denitration equipment (3), the dust removal equipment (4), and the desulfurization equipment (5) are used to sequentially perform denitration, dust removal, and desulfurization on the introduced flue gas material; wherein the flue gas material comprises the high-temperature activation furnace tail gas from the high-temperature activation furnace (2); The adsorption carbon dioxide capture unit (6) comprises a pressurized fan (61), an adsorption tower (62), a vacuum pump (63) and a carbon dioxide product gas storage tank (64); one end of the pressurized fan (61) is connected to the outlet of the desulfurization equipment (5), and the other end is connected to the bottom inlet of the adsorption tower (62) for introducing the gas from the desulfurization equipment (5); the inlet and outlet of the vacuum pump (63) are respectively connected to the bottom outlet of the adsorption tower (62) and the inlet of the carbon dioxide product gas storage tank (64), and the top outlet of the adsorption tower (62) is connected to the chimney (8) of the power plant for adsorbing and capturing carbon dioxide on the introduced gas, outputting the decarbonized gas to the chimney (8) of the power plant for discharge, and outputting the carbon dioxide product gas to the carbon dioxide product gas storage tank (64) for storage.

7. The system according to claim 6, characterized in that The high-temperature activation furnace (2) is connected to the outlet of the carbon dioxide product gas storage tank (64) through its activation medium inlet, and is used to return the carbon dioxide from the carbon dioxide product gas storage tank (64) to the high-temperature activation furnace (2) for use as an activation medium.

8. The system according to claim 6, characterized in that In the adsorption carbon dioxide capture unit (6), there are 3 to 12 adsorption towers (62) which are arranged in parallel.

9. The system according to any one of claims 6 to 8, characterized in that: The system further comprises a power generation unit (7), one end of which is connected to the power plant boiler (1), and the other end of which is connected to the moving equipment in the adsorption carbon dioxide capture unit (6), for introducing and utilizing the heat generated by the mixed combustion of coal and air in the power plant boiler (1) to generate power plant steam, and utilizing the generated power plant steam instead of electrical energy to drive the moving equipment in the adsorption carbon dioxide capture unit (6) to operate.

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