Circulating temperature control type carbon dioxide capturing and utilizing method and device

Abstract

The invention discloses a circulating temperature control type carbon dioxide capture and utilization method and device. CO2-containing high-temperature flue gas enters an adsorption reactor and sequentially passes through the adsorption reactor filled with a bifunctional catalyst, CO2 in the flue gas is adsorbed and captured by a catalytic material in a catalyst bed layer, and the CO2 in the flue gas is collected by the catalytic material in the catalyst bed layer; part of heat generated in the adsorption reaction process is absorbed by a heat accumulator in the catalyst bed layer; when the adsorption reactor reaches the saturated adsorption capacity of the adsorbent, the CO2-containing high-temperature flue gas is switched to enter the conversion reactor, at the moment, the reducing gas enters the adsorption reactor and sequentially penetrates through a catalyst bed layer of the adsorption reactor, and the converted synthesis gas is sent out of the device. By means of the technical process, carbon dioxide adsorption and conversion are completed in situ under the approximate temperature and pressure conditions, the energy utilization rate can be fully increased, the emission reduction cost can be effectively reduced, high energy consumption caused by capture cooling / conversion heating can be avoided, and the high cost of purification and transportation after CO2 capture and potential safety hazards caused by burying are avoided.

Description

Technical Field

[0001] The present invention relates to a method for capturing carbon dioxide from high-temperature gas and in-situ converting it into syngas (hereafter and hereinafter, syngas refers to CO or a mixture of CO with hydrogen, water vapor, etc.), and particularly relates to a method for capturing and utilizing carbon dioxide with cyclic temperature control and its reactor. Background Art

[0002] Carbon capture, utilization, and storage (CCUS: Carbon Capture, Utilization and Storage) is the most important technical path to address global climate change and control greenhouse gas emissions. This "new climate goal" will trigger a huge change in China's energy pattern. In modern industrial production, there are many emission sources of CO 2 , such as cement, steel, electricity, coal chemical industry, and refineries, etc., which are all major emitters of CO 2 . Regarding the CO 2 emission problem, various industries have carried out research and exploration on the capture, utilization, and storage of CO 2 , and each industry has formed a variety of technical methods for the capture, utilization, and storage of CO 2 according to its own industry characteristics.

[0003] Currently, the focus of large-scale research on carbon capture is concentrated in 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 needs to be heat-exchanged step by step to be absorbed at low temperature, and its high solvent cost and high regeneration energy consumption result in an additional energy consumption increase of about 30% in coal-fired power plants. At the same time, the CO 2 captured is stored in different locations, which requires high transportation costs, and problems such as potential safety hazards are also highly questioned. The adsorption method is also relatively mature technically, but it is generally only used in working conditions with determined gas components. The capacity of the adsorbent and the CO 2 selectivity are relatively low, the cost is relatively high, and it is generally only used for low-temperature gases. The membrane method usually cannot achieve high-degree separation and requires multiple stages and / or recycling, resulting in an increase in complexity, energy consumption, and cost. At the same time, impurity components in the gas may also cause blockage. After capturing by the above-mentioned methods, only high-concentration CO 2 gas is obtained, and subsequent transportation, utilization, etc. are also issues worthy of attention. Developing technology for capturing CO 2 and converting it into high-value-added chemicals is the key.

[0004] The specific situations of the main domestic industrial pilot and demonstration projects are as follows: The CO 2 capture demonstration project launched by Huaneng Group at the second Shidongkou Power Plant in Shanghai in December 2009 used the CO 2 capture technology with independent intellectual property rights, and the annual CO 2The scale reaches 120,000 tons, capturing CO 2 Purity reaches over 99.5%. Captured CO 2 Part 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 Capture device. The 250MW IGCC unit of Huaneng Tianjin Green Coal Power was completed and put into operation in 2011, and the 400MW capacity was completed in 2016 and equipped with CO 2 IGCC unit with capture device, the demonstration project aims to research, develop, demonstrate and promote CO 2 Near-zero emission coal-based power generation system can significantly improve power generation efficiency and master the design, construction and operation technology of large-scale coal gasification projects.

[0005] Currently, calcium cycle capture of CO 2 pilot demonstration, including the flue gas CO of La Pereda, Spain's 1.7MWth power plant 2 Capture demonstration system, flue gas CO from Darmstadt's 1MWth power plant in Germany 2 The capture demonstration system adopts a calcium circulation double fluidized bed circulation capture system to achieve CO 2 Capture and regeneration.

[0006] All of the above technologies focus on CO 2 In terms of capture, it does not involve conversion and subsequent utilization. The published patents on CO 2 Research on capture and conversion is mostly focused 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 design of the process and the type of reactor 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. On the one hand, with the switching of capture / conversion process, the coil absorbs heat and extracts heat at the same time, which is difficult to control; on the other hand, due to the uneven reaction in the catalyst bed, it is difficult to avoid local overheating / overcooling. Direct supplementary heating often causes local overheating of the catalyst bed. Taking the commonly used CaO / CaCO 3 For example, when the temperature is > 850-900℃, the adsorbent will melt and sinter, while CO 2 ​​The conversion process generally requires a reaction temperature of 500 - 700 °C or higher. If direct afterburning heating is used, the temperature is too high, and the adsorbent will melt, sinter and deactivate. If the temperature is controlled below 800 °C, due to the temperature difference limitation, the supplementary heat quantity is very limited, or too much fuel gas and combustion-supporting gas need to be supplemented, resulting in serious dilution of the product and a decrease in the concentration of effective gas. If forms such as fluidized beds or moving beds are used, since most industrial flue gases are at atmospheric pressure or low pressure, restricted by pressure, it is basically impossible to achieve with conventional means.

[0007] Chinese Patent CN202110287520.5 discloses a method for synthesizing carbon monoxide syngas by reducing high-temperature molten heat carrier, carbon dioxide and carbon powder. This method uses carbon dioxide and carbon powder to absorb the sensible heat and latent heat emitted by the high-temperature heat carrier and heat up to the reduction temperature to instantaneously reduce it into high-energy carbon monoxide syngas, and uses the high-temperature volume specific heat capacity of carbon dioxide to conduct cyclic heat exchange on the granulated high-temperature heat carrier. The entire process has a long flow, and the core equipment is similar to a fluidized bed, with a large pressure drop. The process temperature frequently changes between 50 °C and 1500 °C. The drastic temperature change will inevitably bring energy consumption problems; and the long flow will bring pressure drop problems. Usually, the pressure of the flue gas is low, and the large pressure drop also limits the use of this technology.

[0008] Chinese Patent CN201821322948.9 discloses a catalytic reaction device, which is provided with a methane + steam hydrogen production catalyst at the lower part to produce hydrogen, carbon dioxide is introduced in the middle part, and a carbon dioxide hydrogenation catalyst is provided at the upper part. Carbon dioxide reacts with hydrogen to produce carbon monoxide gas at the top. The main problems of this patent are: First, carbon dioxide hydrogenation is a strongly endothermic reaction. For every 5% reaction of equivalent ratio of CO 2 and H 2 it will cause a temperature drop of about 150 °C. In the form of this reactor, the reaction actually cannot be self-sustaining and will soon terminate due to temperature reduction; Second, this reactor does not involve carbon capture and is merely a carbon dioxide hydrogenation reactor.

[0009] Chinese CN201410202280.4 discloses a method based on manganese and lanthanide metal catalysts, which hydrogenates carbon dioxide to carry out the reverse water gas shift reaction to produce carbon monoxide. The main problems of this patent are similar to those of CN201821322948.9. First, carbon dioxide hydrogenation is a strongly endothermic reaction. For every 5% reaction of equivalent ratio of CO 2 and H 2 it will cause a temperature drop of about 150 °C. In the form of this reactor, the reaction actually cannot be self-sustaining and will soon terminate due to temperature reduction; Second, this reactor does not involve carbon capture and is merely a carbon dioxide hydrogenation reactor.

[0010] Currently, the patents, literature, etc. publicly available at home and abroad focus on CO 2In the aspects of capture and CO 2 hydrogenation reverse water-gas shift reaction research, while for CO 2 capture and in-situ conversion aspects, there are few related studies. Conducting efficient CO 2 capture at high temperature, and converting the captured CO 2 in-situ into syngas products, so as to facilitate the subsequent synthesis of high-value-added chemical products such as light olefins. This can not only fully improve energy utilization efficiency and effectively reduce emission reduction costs, but also avoid the high energy consumption of capture cooling / conversion heating, solve the high costs of purification and transportation after CO 2 capture, as well as the potential safety hazards brought by storage, and is expected to improve the feasibility and economy of the entire CO 2 emission reduction process, which has important significance. Summary of the Invention

[0011] To solve the above problems, the purpose of the present invention is to provide a method for capturing and utilizing carbon dioxide with cyclic temperature control and its reactor in view of the deficiencies of the above-mentioned prior art, so as to capture CO 2 from high-temperature gas and convert it in-situ into syngas.

[0012] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

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

[0014] 1) High-temperature flue gas containing CO 2 enters the adsorption reactor and sequentially passes through the adsorption reactor equipped with a bifunctional catalyst. CO 2 in the flue gas is adsorbed and captured by the catalytic material in the catalyst bed. Part of the heat generated during the adsorption reaction is absorbed by the heat storage body in the catalyst bed. After the gas reaches the decarbonization standard after passing through each catalyst bed and comes out of the adsorption reactor, it is cooled and then part of it is discharged into the air at high altitude, and part of it enters each bed as cooling gas for cyclic temperature reduction;

[0015] 2) When the adsorption reactor reaches the saturated adsorption capacity of the adsorbent, high-temperature flue gas containing CO 2 switches to enter the conversion reactor. At this time, the reducing gas enters the adsorption reactor, and the reducing gas sequentially passes through the catalyst bed of the adsorption reactor. The catalytic material adsorbed with CO 2 reacts with the reducing gas, and carbon dioxide is reduced to CO. Part of the heat required for the conversion reaction is provided by the heat storage body that has absorbed heat in step 1), and the other part is provided by the heated reducing gas entering each catalyst bed step by step. After the conversion is completed, the syngas is sent out of the device;

[0016] 3) After the conversion reactor reaches the expected saturated adsorption capacity of the adsorbent, the functions of the conversion reactor and the adsorption reactor are interchanged by switching the feed. The flue gas containing CO 2 at high temperature is then switched to enter the adsorption reactor, and the reducing gas is switched to enter the conversion reactor, and the above operations are repeated.

[0017] A method for cyclic temperature-controlled carbon dioxide capture and utilization according to the present invention is further characterized in that: both the catalyst beds of the adsorption reactor and the conversion reactor are filled with catalytic materials and heat storage bodies. The catalytic materials refer to catalysts with dual functions of carbon dioxide adsorption and catalytic conversion, and the heat storage bodies refer to materials with heat storage functions.

[0018] A method for cyclic temperature-controlled carbon dioxide capture and utilization according to the present invention is further characterized in that: the reducing gas mentioned in step 1) reacts with CO 2 to generate a gas such as CO, such as H 2 , CH 4 and C 2 H 6 or a mixture of one or more of these gases, or a mixture of these gases and an inert gas (such as nitrogen).

[0019] A method for cyclic temperature-controlled carbon dioxide capture and utilization according to the present invention is further characterized in that: in step 1), the cooling gas enters each bed for cyclic temperature reduction to ensure that the temperature of the flue gas entering the next catalyst bed is within a suitable range. The adsorption reaction temperature is from room temperature to 800 °C, preferably in the range of 600 - 750 °C.

[0020] A method for cyclic temperature-controlled carbon dioxide capture and utilization according to the present invention is further characterized in that: in step 2), the conversion reaction temperature is 100 - 950 °C, preferably in the range of 600 - 800 °C; the process gas mentioned here refers to the reducing gas containing syngas in the conversion reactor.

[0021] A method for cyclic temperature-controlled carbon dioxide capture and utilization according to the present invention is further characterized in that: in step 2), the reducing gas gradually entering each catalyst bed also serves as a supplement of fresh reducing gas to ensure that the temperature of the process gas entering each catalyst bed is within a suitable range.

[0022] The adsorption reactor and the conversion reactor described in the present invention are the same, which is only for the convenience of description in the present invention. Both the adsorption reactor and the conversion reactor are fixed-bed reactors, which can be single or multiple units. The single unit means being arranged in an overlapping manner or within the same housing, and multiple catalyst beds are provided in the single reactor, with each layer separated by a partition. Multiple reactors can also be provided, and one or more catalyst beds are provided in each reactor. The catalyst beds are filled with catalytic materials and heat storage bodies. The catalytic materials refer to materials 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 bodies refer to materials with heat storage functions, such as corundum, ceramics, mullite, zirconia, or cordierite, etc.

[0023] The gas that can react with CO 2 to generate CO refers to H 2 , CH 4 and C 2 H 6 etc. When these gases are introduced separately, the following reactions will occur:

[0024] CO 2 +2H 2 =CO+H 2 O+H 2 or CO 2 +H 2 =CO+H 2 O

[0025] CO 2 +CH 4 =2CO+2H 2

[0026] 2CO 2 +C 2 H 6 =4CO+3H 2

[0027] The present invention also provides a cyclic temperature-controlled carbon dioxide capture and utilization device for the above cyclic temperature-controlled carbon dioxide capture and utilization method, specifically:

[0028] A cyclic temperature-controlled carbon dioxide capture and utilization device mainly includes an adsorption reactor, a conversion reactor, an inlet heater of the conversion reactor, and an outlet cooler of the adsorption reactor. It is characterized in that: the adsorption reactor is connected to the outlet cooler of the adsorption reactor, and a partial branch at the outlet of the outlet cooler of the adsorption reactor is connected to each catalyst bed of the adsorption reactor.

[0029] A carbon dioxide capture and utilization device with cyclic temperature control according to the present invention is further characterized in that: the adsorption reactor and the conversion reactor are fixed-bed reactors, and a catalytic material and a heat storage body are filled in the catalyst bed. The adsorption reactor and the conversion reactor can each be set up as a single reactor or multiple reactors. The single reactor means being arranged in an overlapping manner or within the same housing, with multiple catalyst beds provided in the single reactor and separated by partition plates between each layer. Multiple reactors can also be provided, with one layer or multiple layers of catalyst beds provided in each reactor. When the adsorption reactor and the conversion reactor are set up with multiple reactors, they can be switched simultaneously or independently one by one.

[0030] The reactor according to the present invention is further characterized in that: the reactor type is bottom-inlet and top-outlet, top-inlet and bottom-outlet, side-inlet and side-outlet, outer-periphery-inlet and middle-outlet, middle-inlet and outer-periphery-outlet, etc.

[0031] The reactor according to the present invention is further characterized in that: a catalytic material and a heat storage body are filled in the catalyst bed. The catalytic material refers to a material with dual functions of carbon dioxide adsorption and catalytic conversion, such as a CaO material loaded with one or more of active components such as Co, Ni, and lanthanide metals; the heat storage body refers to a material with a heat storage function, such as corundum, ceramics, mullite, zircon, or cordierite. The catalytic material and the heat storage body are compounded in a certain proportion. The filling method of the catalytic material and the heat storage body in the catalyst bed is: the catalytic material and the heat storage body are uniformly mixed in a certain proportion and then filled in the catalyst bed; or the catalytic material and the heat storage body are filled layer by layer in the catalyst bed, that is, one layer of catalytic material and one layer of heat storage body are filled in a stratified manner.

[0032] For the reactor according to the present invention, the amount A (m 3 ) of the catalytic material is determined by the amount A1 (t / h) of carbon dioxide to be adsorbed, the material adsorption capacity A2 (t / m 3 ) and the designed switching time A3 (h), and the specific calculation formula is as follows:

[0033] A = A1 × A3 / A2

[0034] Wherein: A1 represents the amount of carbon dioxide to be adsorbed;

[0035] A2 represents the material adsorption capacity;

[0036] A3 represents the designed switching time.

[0037] The amount of the heat storage body is jointly determined by the inlet temperature of the carbon dioxide-containing gas, the gas composition and specific heat, the heat release amount of the reaction of the adsorbed carbon dioxide, the amount and specific heat of the catalytic material, the specific heat of the heat storage body, the heat loss of the reactor, the desired final temperature of the reactor bed to be controlled, etc.

[0038] 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; online control can be performed according to the carbon dioxide content of the gas after decarbonization; other control methods can also be used.

[0039] The present invention is applicable to carbon dioxide-containing gas (such as CO 2 High temperature flue gas, etc.) to capture CO from carbon dioxide-containing gases 2 And convert it into synthesis gas in situ. The optimal temperature range for the present invention is room temperature to 800°C. 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 the like; when the temperature is too low, the temperature can be raised to a suitable temperature range by heating or the like.

[0040] Compared with the prior art, the advantages of the present invention are: 1) The carbon dioxide adsorption and conversion 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 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, because the heat exchange between the conversion process and the adsorption process is continuous and uniform, there will be no problems such as "flying temperature" 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 materials caused by uneven reactions and accidental interruption of heat exchange media in traditional reactors; 3) The heat of the adsorption exothermic / conversion endothermic process can be coupled in situ for utilization, 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, automatic sequence control can be realized, easy to operate and maintain, low investment, small footprint, and strong adaptability.

[0041] The present invention is further described in detail below with the accompanying drawings and specific implementation methods, but they do not limit the scope of the present invention. Brief Description of the Figures

[0042] Figure 1 This is a schematic diagram of the first adsorption and conversion process of a cyclic temperature-controlled carbon dioxide capture and utilization method of the present invention;

[0043] Figure 2 This is a schematic flow chart of the adsorption and conversion process of a cyclic temperature-controlled carbon dioxide capture and utilization method of the present invention;

[0044] Figure 3 This is a schematic diagram of the uniform mixing of catalytic materials and heat storage bodies in a reactor of the present invention.

[0045] The meanings of the numbers in the attached figure are as follows: 1-Contains CO2 High-temperature flue gas, 2 - Gas after decarbonization, 3 - Reducing gas, 4 - Product syngas; 5 - Catalyst bed, 5-1 - Catalytic material, 5-2 - Heat storage body, 6 - Adsorption reactor, 7 - Conversion reactor, 2-1, 2-2, 2-3 - Gas after decarbonization, 3-1, 3-2, 3-3 - Reducing gas; 8, 9 - Coolers at the outlet of the adsorption reactor, 10, 11 - Heaters at the inlet of the conversion reactor; 1#, 2#, 3#, 4# - Beds. Detailed implementation mode

[0046] As Figure 1 shown, it is a simple schematic diagram of a method for cyclic temperature-controlled carbon dioxide capture and utilization, and the process flow of the first adsorption and conversion process. As Figure 2 shown, it is a simple schematic diagram of a method for cyclic temperature-controlled carbon dioxide capture and utilization, and the process flow after the exchange of the adsorption and conversion processes. The number of reactors is at least 2, with 1 reactor in the adsorption reaction state and 1 reactor in the conversion and regeneration state. For the convenience of description, the adsorption reactor and the conversion reactor are used to illustrate the present invention. The reactors of the present invention can also be multiple, with some reactors in the adsorption reaction state and some reactors in the conversion and regeneration state, that is, there can be multiple adsorption reactors and multiple conversion reactors. When multiple reactors are used, they can be switched simultaneously or independently one by one to reduce the impact on the upstream gas such as fluctuations; the reactor can also be a single one, and the internal part is divided into different functional areas by means such as partitions.

[0047] The steps of the cyclic temperature-controlled carbon dioxide capture and utilization method are as follows:

[0048] 1) The CO 2 -containing high-temperature flue gas enters the adsorption reactor 6 and sequentially passes through the beds 1#, 2#, 3#, and 4# of the catalyst bed 5. The CO 2 in the flue gas is adsorbed and captured by the catalytic material in the catalyst bed 5. Part of the heat generated during the adsorption reaction process is absorbed by the heat storage body in the catalyst bed. The gas after decarbonization coming out of the 4# bed is cooled by the cooler 8 at the outlet of the adsorption reactor. Part of the gas after decarbonization 2-1, 2-2, 2-3 is respectively circulated into the 2#, 3#, and 4# beds and mixed with the CO 2 flue gas coming from the upper stage, and the temperature decreases to ensure that the temperature entering the 2#, 3#, and 4# beds meets the requirements. At this time, the adsorption reactor 6 is in the adsorption state, and the adsorption reaction temperature is from normal temperature to 800 °C, preferably in the temperature range of 600 - 750 °C; the heater 11 at the inlet of the conversion reactor is in the bypass state; the control of the gas after decarbonization 2-1, 2-2, 2-3 for circulation can be achieved by control means, and the control is not the core content of this invention and will not be described in detail.

[0049] 2) After the adsorption reactor 6 reaches the saturated adsorption capacity of the adsorbent, the CO-containing 2 high-temperature flue gas 1 is switched to enter the conversion reactor 7. After the reducing gas 3 is heated and raised in temperature by the inlet heater 11 of the conversion reactor, a part of it enters the adsorption reactor 6 and passes through each bed layer 1#, 2#, 3#, and 4# of the catalyst bed layer 5 of the adsorption reactor step by step. The catalytic material that has adsorbed CO 2 reacts with the reducing gas, and carbon dioxide is reduced to CO. Part of the heat required for the conversion reaction is provided by the heat-absorbed regenerator described in step 1), and the remaining part is injected into the 2#, 3#, and 4# bed layers step by step by the reducing gas heated by the inlet heater 11 of the conversion reactor. While the process gas obtains heat, the concentration of the reducing component in the process gas also increases, improving the reduction conversion efficiency. At this time, the adsorption reactor 6 is in the conversion state, and the conversion reaction temperature is 100-950°C, preferably in the temperature range of 600-800°C; the cooler 8 at the outlet of the adsorption reactor is in the bypass state;

[0050] 3) The CO-containing 2 high-temperature flue gas enters the catalyst bed layer of the conversion reactor in sequence, and the CO in the flue gas 2 is adsorbed and trapped by the catalytic material in the catalyst bed layer. The heat generated during the adsorption reaction is absorbed by the regenerator in the catalyst bed layer, and the decarbonized gas 2 exits from the conversion reactor 7;

[0051] 4) After the conversion reactor 7 reaches the saturated adsorption capacity of the adsorbent, the functions of the conversion reactor and the adsorption reactor are interchanged, that is, the conversion reactor is used for the adsorption reaction, and the adsorption reactor is used for the conversion. The CO-containing 2 high-temperature flue gas 1 is switched to enter the adsorption reactor 6 again, and the reducing gas is switched to enter the conversion reactor 7, and the above operations are repeated.

[0052] The 8, 9 - cooler at the outlet of the adsorption reactor can share 1 unit, and the 10, 11 - inlet heater of the conversion reactor can also share 1 unit, and it can be switched through cross-line with each other.

[0053] When the two reactors exchange the feed, there may be steps such as purging before switching in the middle, and the present invention will not elaborate on them one by one.

[0054] The following further illustrates the present invention in conjunction with specific embodiments. The specific embodiments should not be regarded as limiting the protection content of the present invention.

[0055] Embodiment:

[0056] Taking the raw material high-temperature flue gas of 25000 Nm 3 / h as an example, the composition of the flue gas is as follows:

[0057]

[0058]

[0059] The flue gas temperature is 650 °C and the flue gas pressure is 12 kPa. The adsorption reactor 6 and the conversion reactor 7 are switched for operation. When the adsorption reactor 6 is in the adsorption state, the conversion reactor 7 is in the conversion and regeneration state.

[0060] 1) The high-temperature flue gas 1 at 650 °C enters the adsorption reactor 6 from the lower part. At this time, the inlet heater 11 of the conversion reactor is in the bypass state.

[0061] 2) In the catalyst bed 5 of the CaO-based catalytic material and the Al2O3 spherical regenerator in the adsorption reactor 6, the catalytic material is loaded with Co active component for catalyzing the reaction of CO 2 with H 2 .

[0062] 3) According to the calculation, with a switching period of 2.5 hours, 0.82 m 3 of catalytic material needs to be filled in each reactor. The reaction heat release load during the adsorption process is 13.5 MW.

[0063] 4) The flue gas enters the adsorption reactor 6, and the high-temperature CO2 gas sequentially passes through the bed layers 1#, 2#, 3#, and 4# in the catalyst bed 5. In the catalyst bed, CaO in the catalytic adsorption material reacts with CO 2 to generate CaCO 3 , and the released heat raises the temperature of the flue gas and the bed layer. 10.5 MW of heat is absorbed by the regenerator. The decarbonized gas coming out from the top of the adsorption reactor 6 is cooled to 500 °C by the adsorption reactor outlet cooler 8, and then a part is discharged into the air at high altitude. After calculation, the amounts of the decarbonized gas 2-1, 2-2, and 2-3 entering the bed layers 2#, 3#, and 4# are controlled to be 2227.3 m 3 n / h, 1670.5 m 3 n / h, and 1113.6 m 3 n / h respectively, so as to ensure that the temperature of the gas entering the next bed layer is maintained at about 650 °C, and the purified flue gas volume is 11136.3 m 3 n / h, which is discharged from the top of the adsorption reactor 6.

[0064] 5) At the same time, in the conversion reactor 7, CaCO 3 in the catalytic adsorption material reacts with the excessive H heated to 730 °C by the conversion reactor inlet heater 11 2React to generate CaO, CO, and water. Most of the required heat is provided by the heat stored in the heat storage body during the adsorption process, and the insufficient part is heated by the inlet heater 11 of the reforming reactor. Hydrogen 3-1, 3-2, 3-3 is injected into the 2nd, 3rd, and 4th beds step by step. While the process gas obtains heat, the concentration of reducing components in the process gas also increases, improving the reduction and conversion efficiency. At this time, the adsorption reactor outlet cooler 81 is in a bypass state.

[0065] 6) The flow rate of the reaction product syngas 4 is 19183.2 m 3 n / h, and the temperature of the syngas is 500 °C, which is discharged from the gas outlet of the reforming reactor 6. The expected composition of the syngas is as follows:

[0066] Component Composition CO 25.4v％ <![CDATA[H 2 > 43.7v％ <![CDATA[CO 2 > 3.2v％ <![CDATA[H 2 O]]> 27.7v％ Total 100v％

[0067] 7) After 2 hours, the reactor is purged with hot nitrogen, and then the flue gas and hydrogen feed are switched. Then, the cycle is controlled sequentially according to the time sequence.

[0068] The flue gas treated by this embodiment can achieve a reduction in CO 2 emissions of 116,000 t / a, and at the same time, 99,000 t / a of by-product syngas is produced.

Claims

1. A circulating temperature-controlled carbon dioxide capture and utilization method, characterized in that The method comprises the following steps: 1) High-temperature flue gas containing CO2 enters the adsorption reactor and passes through the adsorption reactor equipped with a bifunctional catalyst 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 partially absorbed by the heat storage body in the catalyst bed. After the gas is decarbonized and meets the standards in each catalyst bed, it comes out of the adsorption reactor. After being cooled, part of it is discharged into the air, and part of it is used as cooling gas to enter each bed for circulation and cooling; 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 the reducing gas 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. A part of the heat required for the conversion reaction is provided by the heat storage body after absorbing heat in step 1), and the other part is provided by the heated reducing gas entering each catalyst bed step by step. After the conversion is completed, the synthesis gas is sent out of the device; 3) When the conversion reactor reaches the expected saturated adsorption capacity of the adsorbent, the conversion reactor and the adsorption reactor are functionally interchanged through feed switching. The high-temperature flue gas containing CO2 is then switched into the adsorption reactor, and the reducing gas is switched into the conversion reactor, and the above operation is repeated.

2. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: 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 catalysts with dual functions of carbon dioxide adsorption and catalytic conversion, and the heat storage bodies refer to materials with heat storage function.

3. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The reducing gas refers to a gas that reacts with CO2 to generate CO.

4. The method for capturing and utilizing carbon dioxide according to claim 3, characterized in that: The reducing gas refers to one or a mixture of more than one of H2, CH4 and C2H6, or a mixture of these gases and an inert gas.

5. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The adsorption reaction temperature of step 1) is between room temperature and 800°C, and the conversion reaction temperature of step 2) is between 100°C and 950°C.

6. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The process gas refers to the reducing gas contained in the conversion reactor to generate synthesis gas.

7. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The adsorption reactor and conversion reactor are both fixed bed reactors, and are either single or multiple. The single reactor refers to an overlapping arrangement or in the same shell, with multiple layers of catalyst beds arranged in a single reactor, and each layer is separated by a partition. Multiple reactors can also be set up, with one or more layers of catalyst beds arranged in each reactor. The gas phase from the top condenser of the dehydration tower described in step 4) is cooled again by the top aftercooler of the dehydration tower and then sent to the gas-liquid separator; the operating temperature of the top aftercooler of the dehydration tower is controlled at -5 to -10°C, and the operating temperature of the top liquid-liquid phase separator is controlled at 5 to 10°C. Both the gas-liquid separator and the top liquid-liquid phase separator are operated at normal pressure, and the operating pressure is controlled at 100 to 105kPa.

8. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: When the adsorption reactor and the conversion reactor are a single unit, multiple layers of catalyst beds are arranged in the single reactor, and each layer is separated by a partition.

9. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: When multiple adsorption reactors and conversion reactors are provided, one or more catalyst beds are provided in each reactor.

10. A circulating temperature-controlled carbon dioxide capture and utilization device, mainly comprising an adsorption reactor, a conversion reactor, a conversion reactor inlet heater and an adsorption reactor outlet cooler, characterized in that: The adsorption reactor is connected to an adsorption reactor outlet cooler at the bottom, and an outlet branch of the adsorption reactor outlet cooler is connected to each catalyst bed of the adsorption reactor at the bottom.

11. The carbon dioxide capture and utilization device according to claim 10, characterized in that: The adsorption reactor and the conversion reactor are fixed bed reactors, and the catalyst bed is filled with catalytic materials and heat storage bodies.

12. The carbon dioxide capture and utilization device according to claim 11, characterized in that: The catalytic material refers to a CaO material loaded with one or more than two active components of Co, Ni and lanthanide metals; the heat storage body refers to corundum, ceramics, mullite, zircon or cordierite.

13. The carbon dioxide capture and utilization device according to claim 10, 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, middle-in and periphery-out.

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