Carbon dioxide capture and utilization method and reactor thereof

Abstract

The invention discloses a method for capturing and utilizing carbon dioxide and a reactor thereof, which are used for capturing CO2 from high-temperature gas and converting the CO2 into synthesis gas in situ. CO2-containing high-temperature flue gas enters an adsorption reactor, CO2 in the flue gas is adsorbed and captured by a catalytic material in a catalyst bed layer, heat generated in the adsorption reaction process is absorbed by a heat accumulator in the catalyst bed layer, and when the adsorption reactor reaches the saturated adsorption capacity of an adsorbent, the CO2-containing high-temperature flue gas is switched to enter a conversion reactor; at the moment, the reducing gas enters the adsorption reactor, after the conversion reactor reaches the expected saturated adsorption capacity of the adsorbent, the CO2-containing high-temperature flue gas is switched to enter the adsorption reactor, the reducing gas is switched to enter the conversion reactor, and the operation is repeated. By means of the device, the energy utilization rate can be fully increased, the emission reduction cost is effectively reduced, and heat in-situ coupling utilization in the adsorption heat release / conversion heat absorption process can be achieved.

Description

Technical Field

[0001] The present invention relates to a method for capturing carbon dioxide from high-temperature gas and converting it into synthesis gas (synthesis gas here and hereinafter refers to CO or a mixture of CO and hydrogen, water vapor, etc.), and specifically to a method for capturing and utilizing carbon dioxide and a reactor thereof. Background Art

[0002] Carbon capture, utilization and storage (CCUS) is the most important technical path to address global climate change and control greenhouse gas emissions. 2 There are many sources of CO emissions, such as cement, steel, electricity, coal chemical industry and refineries. 2 Major emitters of CO 2 Emissions issues, all industries have carried out CO 2 Each industry has formed a variety of CO2 capture, utilization and storage research and exploration according to its own characteristics. 2 Technological approaches to capture, utilization and storage.

[0003] At present, the focus of large-scale research on carbon capture is on the power industry. Among them, the chemical absorption capture method for flue gas after combustion in coal-fired power plants is a relatively mature technology. However, high-temperature flue gas requires step-by-step heat exchange to be absorbed at low temperatures, and its solvent cost is high and the regeneration energy consumption is high, resulting in an additional increase of about 30% in the energy consumption of coal-fired power plants. At the same time, the captured CO 2 Offsite storage requires high transportation costs and is also subject to questionable safety issues. Adsorption is also relatively mature in technology, but is generally only used in conditions where the gas composition is determined. The capacity of the adsorbent and CO 2 The selectivity is low, the cost is high, and it is generally only used for low-temperature gases. Membrane methods usually cannot achieve a high degree of separation and require multiple stages and / or recycling, which leads to increased complexity, energy consumption and cost. At the same time, impurities in the gas may also cause blockage. After the above methods are captured, only high-concentration CO 2 Gas, subsequent transportation, and utilization are also issues that deserve attention. 2 The key is the technology to capture and convert it into high value-added chemicals.

[0004] The details of the major industrial pilot and demonstration projects are as follows: The CO2-based power plant started by Huaneng Group in December 2009 at the Shanghai Shidongkou Second Power Plant 2 The capture demonstration project used a CO 2 Capture technology, CO captured annually 2 The scale reaches 120,000 tons, capturing CO 2The purity reaches over 99.5%. The captured CO 2 Some of it is used in the food processing industry after passing through the refining system, and the rest is used in industrial production. When it was put into operation, the capture device was the largest coal-fired power plant flue gas CO 2 The 250MW IGCC unit of Huaneng Tianjin Green Coal Power was completed and put into operation in 2011, and the 400MW unit with CO 2 The IGCC unit with capture device is designed to research, develop, demonstrate and promote CO 2 The near-zero-emission coal-based power generation system can significantly improve power generation efficiency and master the design, construction and operation technologies of large-scale coal gasification projects.

[0006] All of the above technologies focus on CO 2 In terms of capture, it does not involve conversion and subsequent utilization. 2 Most of the research on capture and conversion focuses on catalysts. 2 Capture is a highly exothermic reaction, and the conversion process is a highly endothermic reaction. The temperature and heat control of the reaction process is extremely critical. The process design and reactor type are the key to determining whether the technology is feasible. For highly endothermic and exothermic reactions, the measures usually taken include: using coils to take heat / supplement heat, using direct combustion heating, using fluidized beds, moving beds, etc. These methods are used for CO 2 There are some problems in both capture and conversion. When using coils to take heat / supplement heat, on the one hand, as the capture / conversion process switches, the coils absorb heat and take heat at times, which makes control difficult; on the other hand, due to the uneven reaction in the catalyst bed, it is difficult to avoid local overheating / overcooling. When using direct supplementary heating, there is often a problem of local overheating of the catalyst bed. Taking the commonly used CaO / CaCO 3 For example, when the temperature is > 850-900°C, the adsorbent will melt and sinter, while CO 2 The conversion process generally requires a reaction temperature of 500-700℃ or above. If direct supplementary heating is used, the temperature is too high and the adsorbent will melt, sinter and become inactive. If the temperature is controlled to less than 800℃, the supplementary heat is very limited due to the temperature difference, or too much fuel gas and combustion-supporting gas are required, resulting in serious dilution of the product and a decrease in the effective gas concentration. If a fluidized bed or moving bed is used, since most industrial flue gas is at normal pressure or low pressure, it is basically impossible to achieve this by conventional means due to pressure limitations.

[0007] CN202110287520.5 discloses a method for reducing carbon monoxide synthesis gas with a high-temperature molten heat carrier, carbon dioxide and carbon powder. The method uses carbon dioxide and carbon powder to absorb the sensible heat and latent heat emitted by the high-temperature heat carrier and heat it to the reduction temperature to instantly reduce it to carbon monoxide high-energy synthesis gas, and uses the high-temperature volumetric heat capacity of carbon dioxide to circulate heat exchange on the granulated high-temperature heat carrier. The whole process is long, and the core equipment is similar to a fluidized bed, with a large pressure drop. The process temperature changes frequently between 50℃ and 1500℃, and the drastic temperature change will inevitably bring energy consumption problems; and the longer process will bring pressure drop problems. Usually, the flue gas pressure is low, and the large pressure drop also limits the use of this technology.

[0008] CN201821322948.9 discloses a catalytic reaction device, wherein a methane + water vapor hydrogen production catalyst is provided at the bottom to produce hydrogen, carbon dioxide is introduced into the middle, and a carbon dioxide hydrogenation catalyst is provided at the top. Carbon dioxide reacts with hydrogen to produce carbon monoxide gas at the top. The main problem with this patent is that, first, carbon dioxide hydrogenation is a strongly endothermic reaction, and the equivalent ratio of CO 2 and H 2 Every 5% reaction will cause a temperature drop of about 150°C. Under this type of reactor, the reaction is actually unsustainable and will soon terminate due to the temperature drop. Second, this reactor does not involve carbon capture, but is merely a carbon dioxide hydrogenation reactor.

[0009] CN201410202280.4 discloses a method based on manganese and lanthanide metal catalysts to hydrogenate carbon dioxide and perform a reverse water gas reaction to generate carbon monoxide. The main problems of this patent are similar to those of CN201821322948.9. First, the hydrogenation of carbon dioxide is a strongly endothermic reaction. The equivalent ratio of CO 2 and H 2 Every 5% reaction will cause a temperature drop of about 150°C. Under this type of reactor, the reaction is actually unsustainable and will soon terminate due to the temperature drop. Second, this reactor does not involve carbon capture, but is merely a carbon dioxide hydrogenation reactor.

[0010] At present, the patents and documents published at home and abroad are concentrated in CO 2 Capture and CO 2 In the study of the hydrogenation reverse water gas reaction, 2 There are few studies on capture and in-situ conversion. 2 Efficient capture of CO 2 In-situ conversion into synthesis gas products is convenient for the subsequent synthesis of light olefins and other chemical products with high added value. This can not only fully improve energy utilization and effectively reduce emission reduction costs, but also avoid the high energy consumption of capture cooling / conversion heating, and solve the problem of CO 2The high cost of post-capture purification and transportation, as well as the safety risks of storage, are expected to increase the overall CO 2 The feasibility and economy of the emission reduction process are of great significance. Summary of the invention

[0011] The purpose of the present invention is to provide a carbon dioxide capture and utilization method and a reactor thereof to capture CO from high temperature gas. 2 and convert it into synthesis gas in situ.

[0012] The technical solution of the present invention is:

[0013] A method for capturing and utilizing carbon dioxide, characterized in that the method comprises the following steps:

[0014] 1) Containing CO 2 The high-temperature flue gas enters the adsorption reactor and passes through the catalyst bed of the adsorption reactor in sequence. 2 The carbonized gas is adsorbed and captured by the catalytic material in the catalyst bed. The heat generated during the adsorption reaction is absorbed by the heat storage body in the catalyst bed. The decarbonized gas comes out of the adsorption reactor. The adsorption reaction temperature is between room temperature and 800°C, with a preferred temperature range of 600-750°C.

[0015] 2) When the adsorption reactor reaches the saturated adsorption capacity of the adsorbent, the CO 2 The high-temperature flue gas switches to the conversion reactor, and the reducing gas enters the adsorption reactor and passes through the catalyst bed of the adsorption reactor in turn, adsorbing CO 2 The catalytic material reacts with the reducing gas, and the carbon dioxide is reduced to CO. The heat required for the conversion reaction is provided by the heat storage body after the heat absorption in step 1), and the insufficient part is supplemented by a heater or other external heat source. The conversion reaction temperature is 100 to 950°C, preferably in the range of 600 to 800°C;

[0016] 3) CO2-containing gas entering the conversion reactor 2 The high-temperature flue gas passes through the catalyst bed of the conversion reactor in sequence, and the CO in the flue gas 2 It is adsorbed and captured by the catalytic material in the catalyst bed, and the heat generated during the adsorption reaction is absorbed by the heat storage body in the catalyst bed;

[0017] 4) When the conversion reactor reaches the expected adsorbent saturation adsorption capacity, the CO 2 The high-temperature flue gas is then switched to enter the adsorption reactor, and the reducing gas is switched to enter the conversion reactor, and the above operation is repeated.

[0018] The catalyst beds of the adsorption reactor and the conversion reactor are both filled with catalytic materials and heat storage bodies. The catalytic materials refer to materials having dual functions of carbon dioxide adsorption and catalytic conversion, and the heat storage bodies refer to materials having heat storage functions.

[0019] The reducing gas refers to CO 2 The gas that reacts to generate CO may be one or a mixture of two or more of these gases, or a mixture of these gases and an inert gas (such as nitrogen).

[0020] The adsorption reactor and the conversion reactor described in the present invention are the same, and are only for the convenience of description in the present invention. Both the adsorption reactor and the conversion reactor are fixed bed reactors, and are single or multiple, and the catalyst bed is filled with catalytic materials and heat storage bodies. The catalytic material refers to a material with dual functions of carbon dioxide adsorption and catalytic conversion, such as CaO materials loaded with one or more active components such as Co, Ni and lanthanide metals; the heat storage body refers to a material with heat storage function, such as corundum, ceramics, mullite, zircon or cordierite.

[0021] The can be 2 The gas that reacts to produce CO is H 2 , CH 4 and C 2 H 6 When these gases are introduced separately, the following reactions will occur:

[0022] CO 2 +2H 2 =CO+H 2 O+H 2 or CO 2 +H 2 =CO+H 2 O

[0023] CO 2 +CH 4 =2CO+2H 2

[0024] 2CO 2 +C 2 H 6 =4CO+3H 2

[0025] The present invention also provides a reactor, which is used as an adsorption reactor and a conversion reactor for the above-mentioned carbon dioxide capture and utilization method, characterized in that: the reactor is a fixed bed reactor, including a catalyst bed, a gas inlet, a gas outlet and an air inlet distributor, the air inlet distributor is arranged at the gas inlet, the catalyst bed is filled with catalytic materials and a heat storage body, and the catalyst bed is a single-layer arrangement or a multi-layer arrangement, preferably a multi-layer arrangement. Both the adsorption reactor and the conversion reactor can be arranged with one or more reactors. When the adsorption reactor and the conversion reactor are arranged with multiple reactors, they can be switched for operation simultaneously or independently switched for operation one by one.

[0026] The reactor of the present invention has further technical characteristics in that the reactor is of the type of bottom-in and top-out, top-in and bottom-out, side-in and side-out, periphery-in and middle-out, middle-in and periphery-out, etc.

[0027] The reactor described in the present invention has a further technical feature that: the catalytic material and the heat storage body are compositely composed in a certain proportion. The higher the proportion of the heat storage body, the lower the bed temperature rise, but the effective space utilization rate of the bed is also lower, and vice versa. The catalytic material and the heat storage body are loaded into the catalyst bed in the following manner: the catalytic material and the heat storage body are evenly mixed in a certain proportion and then loaded into the catalyst bed; or the catalytic material and the heat storage body are loaded layer by layer in the catalyst bed, that is, a layer of catalytic material and a layer of heat storage body are loaded in layers. The ratio of the catalytic material and the heat storage body determines the temperature rise of the gas before and after adsorption. When no heat storage body is included, common CO 2 For flue gas with a content of 5-20v%, the maximum temperature rise of the purified gas after adsorption can reach more than 600℃ compared with the carbon dioxide-containing gas before adsorption. The higher the proportion of the heat storage body, the lower the temperature rise of the purified gas after adsorption. The specific ratio of the catalytic material and the heat storage body can be determined based on comprehensive considerations such as the design temperature of the reactor, the inlet carbon dioxide-containing gas temperature, and the maximum tolerance temperature of the catalytic material. Generally, the recommended volume ratio of the catalytic material to the heat storage body ranges from 5:1 to 1:10.

[0028] The reactor of the present invention, the amount of catalytic material A (m 3 ) is determined by the amount of carbon dioxide to be adsorbed A1 (t / h), the material adsorption capacity A2 (t / m 3 ) and the design switching time A3(h), the specific calculation formula is as follows:

[0029] A=A1xA3 / A2

[0030] Where: A1 represents the amount of carbon dioxide to be adsorbed;

[0031] A2 represents the adsorption capacity of the material;

[0032] A3 expresses the design switching time.

[0033] The amount of the heat storage body is determined by the inlet temperature of the carbon dioxide-containing gas, the gas composition and specific heat, the heat release of the adsorbed carbon dioxide reaction, the amount and specific heat of the catalytic material, the specific heat of the heat storage body, the reactor heat loss, the final temperature of the reactor bed that is desired to be controlled, etc.

[0034] The heat B (kJ / h) supplemented by the heater or other external heat source in the present invention depends on the heat released by the heat storage body B1 (kJ / h), the heat loss of the reactor B2 (kJ / h), the heat absorbed by the conversion process B3 (kJ / h), the total heat brought in by the inlet reducing gas B4 (kJ / h) and the total heat taken away by the outlet synthesis gas B5 (kJ / h). The specific calculation formula is as follows:

[0035] B=B2+B3-B1-B4+B5

[0036] Where: B1 represents the heat released by the heat storage body;

[0037] B2 represents the heat loss of the reactor;

[0038] B3 represents the heat absorbed during the conversion process;

[0039] B4 represents the total heat brought in by the inlet reducing gas;

[0040] B5 represents the total heat carried away by the outlet synthesis gas.

[0041] The reactor of the present invention is further characterized in that the specific number of layers C of the reactor depends on the following factors: the heat C1 (kJ / h) that the reactor needs to supplement through a heater or other external heat source, the flow rate C2 (kg / h) of the gas in the reactor during adsorbent conversion and regeneration, the maximum allowable temperature C3 (°C) of the gas in the reactor during adsorbent conversion and regeneration, the minimum allowable temperature C4 (°C) of the gas in the reactor during adsorbent conversion and regeneration, and the specific heat capacity C5 (kJ / kg-°C) of the gas in the reactor during adsorbent conversion and regeneration. The calculation formula is as follows, where the Roundup function represents rounding up:

[0042] C=Roundup(C1 / C2 / (C3-C4) / C5)

[0043] Where: C1 represents the heat that the reactor needs to supplement through a heater or other external heat source;

[0044] C2 represents the gas flow rate in the reactor during adsorbent conversion and regeneration;

[0045] C3 represents the maximum allowable temperature of the gas in the reactor during adsorbent conversion and regeneration;

[0046] C4 represents the minimum allowable temperature of the gas in the reactor during adsorbent conversion and regeneration;

[0047] C5 represents the specific heat capacity of the gas in the reactor during adsorbent conversion and regeneration.

[0048] In the actual process, the amount and composition of the gas in the reactor will change each time it passes through a bed layer, so it is necessary to calculate layer by layer, but the calculation principle is the same. Practitioners in this profession only need to make a slight deduction based on the above formula to calculate the corresponding number of layers.

[0049] The desired adsorption conditions (saturated adsorption capacity of the adsorbent) of the present invention can be achieved by timing control according to the designed switching time; by online control according to the carbon dioxide content of the gas after decarbonization; or by other control methods.

[0050] The present invention is applicable to carbon dioxide-containing gas (such as CO 2 High temperature flue gas, etc.) to capture CO from gases containing carbon dioxide 2 And it is converted into synthesis gas in situ. When the temperature of the gas to be treated is too high, the temperature can be reduced to a suitable temperature range by recovering heat or other means; when the temperature is too low, the temperature can be raised to a suitable temperature range by heating or other means.

[0051] Compared with the prior art, the advantages of the present invention are: 1) The carbon dioxide adsorption and conversion of the present invention are completed in situ under similar temperature and pressure conditions, which can fully improve the energy utilization rate and effectively reduce the emission reduction cost, and avoid the high energy consumption of capture cooling / conversion heating, thus solving the problem of CO 2 1) The high cost of purification and transportation after capture, as well as the potential safety hazards caused by burial; 2) In the reactor of the present invention, due to the composite structure of the heat storage body and the catalytic material, the temperature is controlled by the heat storage body itself, and there will be no problems such as "temperature runaway" and "local hot spots" that may cause equipment damage. The reactor is inherently safe and can completely avoid the possibility of overheating and damage to the reactor and catalytic material caused by uneven reaction and accidental interruption of the heat exchange medium in traditional reactors; 3) The in-situ coupled utilization of heat from the adsorption exothermic / conversion endothermic process can be achieved, which saves more than 50% energy compared with existing reactors; 4) The reactor has a low pressure drop and can be applied to most flue gas conditions; 5) The process is simple, easy to operate and maintain, with low investment and small footprint.

[0052] The present invention will be further described in detail below with the accompanying drawings and specific embodiments, but the scope of the present invention is not limited thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a simple schematic diagram of a method for capturing and utilizing carbon dioxide according to the present invention.

[0054] Figure 2 It is a schematic diagram of uniformly mixed loading of catalytic materials and heat storage bodies in a reactor of the present invention.

[0055] Figure 3 It is a schematic diagram of the structure of a reactor of the present invention.

[0056] The reference numerals shown in the figures are:

[0057] 1-Contains CO 2 High-temperature flue gas, 2-reducing gas, 3-decarbonized gas, 4-synthesis gas, 5-adsorption reactor, 6-conversion reactor, 7-catalyst bed, 7-1-catalytic material, 7-2 heat storage body, 8-heater, 9-reactor gas inlet, 10-inlet distributor, 11-reactor gas outlet, 12, 13, 14, 15, 16, 17, 18, 19-control valves. DETAILED DESCRIPTION

[0058] like Figure 1 , Figure 2 and Figure 3 As shown, a carbon dioxide capture and utilization method and a reactor thereof. The number of reactors is at least 2. Figure 1 There are two reactors shown in the figure, one of which is in the adsorption reaction state and the other is in the conversion regeneration state. For the convenience of description, the present invention is described using an adsorption reactor and a conversion reactor. The reactors of the present invention can also be multiple, some of which are in the adsorption reaction state and some of which are in the conversion regeneration state, that is, there can be multiple adsorption reactors and multiple conversion reactors. When multiple reactors are used, they can be switched at the same time or independently switched one by one to reduce the impact of fluctuations on the upstream gas.

[0059] For the convenience of description, two reactors are used as an example. Figure 1 As shown, there are two reactors, one is an adsorption reactor and the other is a conversion reactor. Before the device starts operating, control valves 12 to 19 are all in a closed state. The steps of the carbon dioxide capture and utilization method are:

[0060] 1) Control valves 12 and 16 are open, containing CO 2 The high-temperature flue gas 1 enters the adsorption reactor 5 through the control valve 12 and passes through the adsorption reactor catalyst bed 7 in sequence. 2 The carbonized gas 3 is adsorbed and captured by the catalytic material in the catalyst bed, and the heat generated in the adsorption reaction process is absorbed by the heat storage body in the catalyst bed. The decarbonized gas 3 comes out of the adsorption reactor 5 through the control valve 16. At this time, the adsorption reactor 5 is in the adsorption state, and the adsorption reaction temperature is room temperature to 800°C, preferably in the temperature range of 600 to 750°C.

[0061] 2) When the adsorption reactor 5 reaches the saturated adsorption capacity of the adsorbent, the control valves 12 and 16 are closed, the control valves 14 and 19 are opened, and the CO 2The high-temperature flue gas 1 is switched into the conversion reactor 6 through the control valve 14. At this time, the control valves 13 and 17 are opened, and the reducing gas 2 enters the adsorption reactor 5 through the control valve 13 and passes through the adsorption reactor bed 7 in sequence to adsorb CO 2 The catalytic material reacts with the reducing gas, and the carbon dioxide is reduced to CO. The heat required for the conversion reaction is provided by the heat storage body after the heat absorption in step 1), and the insufficient part is supplemented by the heater 8 or other external heat sources. The synthesis gas 4 comes out of the adsorption reactor 5 through the control valve 17. At this time, the adsorption reactor 5 is in a conversion state, and the conversion reaction temperature is 100-950°C, preferably in the temperature range of 600-800°C;

[0062] 3) CO2-containing gas entering the conversion reactor 6 2 The high-temperature flue gas passes through the catalyst bed of the conversion reactor in sequence, and the CO in the flue gas 2 The gas is adsorbed and captured by the catalytic material in the catalyst bed, and the heat generated during the adsorption reaction is absorbed by the heat storage body in the catalyst bed. The decarbonized gas 3 comes out of the conversion reactor 6 through the control valve 19;

[0063] 4) When the conversion reactor reaches the saturated adsorption capacity of the adsorbent, control valves 14 and 19 are closed, 12 and 16 are opened, and the CO 2 The high-temperature flue gas 1 is then switched to enter the adsorption reactor 5, the control valves 13 and 17 are closed, 15 and 18 are opened, the reducing gas is switched to enter the conversion reactor, and the above operation is repeated.

[0064] The reactor of the present invention is shown in Figure 3 As shown, the reactor is a fixed bed reactor, comprising a reactor gas inlet 9, an air inlet distributor 10, a reactor gas outlet 111, a catalyst bed 7 and a heater 8. The catalyst bed 7 has four layers, each of which is composed of a catalytic material and a heat storage body in a certain proportion. The catalytic material and the heat storage body are evenly mixed. The filling method of the catalytic material and the heat storage body is shown in FIG. Figure 2 As shown, Figure 2 In the process, the catalytic material 7-1 and the heat storage body 7-2 are filled after being mixed evenly. The advantage of such filling is that the temperature of the catalyst bed is not limited by the reaction rate, the reaction uniformity, etc., and always remains stable.

[0065] The catalyst bed of the present invention generally needs to be arranged in multiple layers, each of which is filled with catalytic materials and heat storage bodies. The heater is also arranged in multiple stages between the beds or the process gas is led out of the reactor and heated by other external heat sources before returning.

[0066] The exchange of feeds between the two reactors may involve steps such as purging before switching, which will not be described in detail in the present invention.

[0067] The present invention is further described below in conjunction with specific embodiments, which should not be considered as limiting the scope of protection of the present invention.

[0068] Example

[0069] Raw material high temperature flue gas 148500m 3 Take n / h as an example, the flue gas composition is as follows:

[0070] Flue gas composition v％ <![CDATA[CO 2 ]]> 17 <![CDATA[H 2 The]]> 5 <![CDATA[N 2 ]]> 75 <![CDATA[O 2 ]]> 3

[0071] The flue gas temperature is 678°C and the flue gas pressure is 10 kPa. The adsorption reactor 5 and the conversion reactor 6 are switched to operate. When the adsorption reactor 5 is in the adsorption state, the conversion reactor 6 is in the conversion regeneration state.

[0072] 1) The control valves 12 and 16 are opened, and the 678°C high temperature flue gas 1 enters the adsorption reactor 5 from the bottom.

[0073] 2) The adsorption reactor 5 contains CaO-based catalytic materials and Al 2 O 3 The catalyst bed 7 of the spherical heat storage body has a Co active component loaded on the catalyst material for catalyzing CO 2 Reaction with H2. ;

[0074] 3) According to calculations, 3.85m3 of catalytic material needs to be filled in each reactor according to a 2-hour switching cycle. The exothermic load of the adsorption process is 42.61MW. Taking into account the changes in the composition and amount of the inlet and outlet gases, a total heat storage load of 51.79MW is required in the reactor. In order to control the reactor temperature not higher than 750℃ (1023K), the proportion of catalytic materials in the reactor is calculated to be 25%, that is, when the ratio of heat storage body to catalytic material is 3:1, the final temperature of the flue gas after decarbonization at the reactor outlet is 727℃, which meets the requirements.

[0075] 4) The control valves 12 and 16 are opened, and the flue gas enters the adsorption reactor 5 through the control valve 12 and passes through the gas distributor 10 ( Figure 1 The CaO in the catalytic adsorption material and the CO 2 The reaction produces CaCO 3 The released heat increases the temperature of the flue gas and the bed. After adsorption in the adsorption reactor 5, the purified flue gas temperature is 727°C and the flue gas volume is 124517.3m3n / h. After coming out of the gas outlet 11 of the adsorption reactor 5, it is sent to the chimney for discharge after heat recovery.

[0076] 5) At the same time, the control valves 15 and 18 are opened, and in the other conversion reactor 6, the CaCO in the catalytic adsorption material 3The excess H at 730°C introduced through the gas inlet 9 and the gas distributor 10 2 Reaction to produce CaO, CO and water.

[0077] During this process, the heat absorption load of the conversion and regeneration reaction is 51.5MW. Combined with the energy difference between the inlet and outlet gases and the heat loss of the reactor, the total required heat supplement load is 82.8MW. After deducting the stored heat released by the heat storage body, the total heat supplement load is 31.0MW. During this process, in order to enable the conversion and regeneration process to proceed, the temperature in the reactor needs to be maintained at not less than 600°C; to ensure that the catalytic material is not damaged, the maximum temperature of the catalyst bed needs to be controlled not to exceed 750°C (1023K). In this process, each time the gas is heated from 600°C to 750°C, heat supplement can only be performed at a load of no more than 4.7MW. Therefore, it can be obtained that the heat supplement needs to be carried out in seven stages, that is, the catalyst bed 7 is heated according to Figure 3 As shown, it is divided into 8 layers, and electric heaters 8 are arranged between the layers. The heating load of the electric heaters in each layer is 4.4MW.

[0078] 6) The amount of reaction product synthesis gas 4 is 60535m 3 n / h, the synthesis gas temperature is 600°C, and it is discharged through the gas outlet 11 of the reactor 6. The expected composition of the synthesis gas is as follows:

[0079] Element composition CO 26.8v％ <![CDATA[H 2 ]]> 45.0v％ <![CDATA[CO 2 ]]> 1.4v％ <![CDATA[H 2 The]]> 26.8v％ total 100v％

[0080] 7) After 2 hours, the reactor is purged with hot nitrogen, and control valves 12, 15, 16, and 18 are closed, and valves 13, 14, 17, and 19 are opened, and the flue gas and hydrogen feed are switched. Then the cycle is carried out in sequence according to the time sequence control.

[0081] The flue gas treated by this embodiment can achieve CO 2 Emissions were reduced by 332,000 t / a, while 363,000 t / a of synthesis gas were produced as a by-product.

Claims

1. A method for capturing and utilizing carbon dioxide, characterized in that: The method comprises the following steps: 1) High-temperature flue gas containing CO2 enters the adsorption reactor and passes through the catalyst bed of the adsorption reactor in sequence. The CO2 in the flue gas is adsorbed and captured by the catalytic material in the catalyst bed. The heat generated during the adsorption reaction is absorbed by the heat storage body in the catalyst bed. The gas comes out of the adsorption reactor after decarbonization. The adsorption reaction temperature is room temperature to 800℃; 2) When the adsorption reactor reaches the saturated adsorption capacity of the adsorbent, the high-temperature flue gas containing CO2 switches to enter the conversion reactor. At this time, the reducing gas enters the adsorption reactor and passes through the catalyst bed of the adsorption reactor in sequence. The catalytic material adsorbing CO2 reacts with the reducing gas, and the carbon dioxide is reduced to CO. The heat required for the conversion reaction is provided by the heat storage body after absorbing heat in step 1), and the insufficient part is supplemented by a heater or other external heat source. The conversion reaction temperature is 100-950°C; 3) The high-temperature flue gas containing CO2 entering the conversion reactor passes through the catalyst bed of the conversion reactor in sequence, and the CO2 in the flue gas is adsorbed and captured by the catalytic material in the catalyst bed, and the heat generated during the adsorption reaction is absorbed by the heat storage body in the catalyst bed; 4) When the conversion reactor reaches the expected saturated adsorption capacity of the adsorbent, the high-temperature flue gas containing CO2 is switched to enter the adsorption reactor, and the reducing gas is switched to enter the conversion reactor, and the above operation is repeated; The catalyst beds of the adsorption reactor and the conversion reactor are filled with catalytic materials and heat storage bodies, wherein the catalytic materials refer to materials having dual functions of carbon dioxide adsorption and catalytic conversion, and the heat storage bodies refer to materials having heat storage functions; The reducing gas refers to a gas that can react with CO2 to generate CO, or a mixture of one or more of these gases, or a mixed gas of an inert gas and one or more of these gases.

2. A method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The adsorption reaction temperature in step 1) is 600-750°C, and the conversion reaction temperature in step 2) is 600-800°C.

3. A method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The adsorption reactor and the conversion reactor are the same, both are fixed bed reactors, and both are single or multiple.

4. A method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The catalytic material is a CaO material loaded with one or more than two active components of Co, Ni and lanthanide metals, and the heat storage body is corundum, ceramic, mullite, zircon or cordierite.

5. A method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The gases that can react with CO2 to generate CO refer to H2, CH4 and C2H6.

6. A method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The catalytic material and the heat storage body are uniformly mixed and then loaded into the catalyst bed; or the catalytic material and the heat storage body are loaded layer by layer in the catalyst bed, that is, a layer of catalytic material and a layer of heat storage body are loaded in layers.

7. A reactor, as an adsorption reactor or a conversion reactor, used in the carbon dioxide capture and utilization method according to claim 1, characterized in that: The reactor is a fixed bed reactor, including a catalyst bed, a gas inlet, a gas outlet and an air inlet distributor. The air inlet distributor is arranged at the gas inlet. The catalyst bed is filled with catalytic materials and heat storage bodies. The catalyst bed is a single-layer arrangement or a multi-layer arrangement. The adsorption reactor and the conversion reactor are respectively arranged with one or more reactors. When multiple reactors are arranged, they can be switched for operation simultaneously or independently one by one.

8. A reactor according to claim 7, characterized in that: The reactor type is bottom-in and top-out, top-in and bottom-out, side-in and side-out, periphery-in and middle-out, or middle-in and periphery-out.

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