Self-heat balance type carbon dioxide capture and utilization method and device

Abstract

The invention discloses a method for capturing carbon dioxide from high-temperature gas and converting the carbon dioxide into synthesis gas in situ, and particularly relates to a self-heat balance type carbon dioxide capturing and utilizing method and device. Reaction solvent recovery liquid from a reaction unit enters a feed liquid-liquid phase splitter and is divided into an oil phase and a water phase in the phase splitter; a water phase from the upper layer of the feed liquid-liquid phase splitter enters the upper part of the deoiling tower, and an oil phase from the lower layer of the feed liquid-liquid phase splitter enters the upper part of the dehydrating tower; a liquid phase extracted from the top of the deoiling tower and a liquid phase obtained from a fractional condenser at the top of the dehydrating tower are respectively fed into a tower top liquid-liquid phase splitter; tower bottoms from the dehydrating tower are fed into a dichloromethane refining tower; the tower kettle of the dichloromethane refining tower is pumped into a propylene carbonate product tower; and a qualified propylene carbonate product is extracted from a side line at the lower part of the propylene carbonate product tower. According to the technical process provided by the invention, the recovery of the reaction solvent is realized, and the byproduct propylene carbonate with high additional value is obtained. The treatment difficulty of the three wastes is reduced, and the facility load and the treatment cost for treating the three wastes are reduced.

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 self-heating equilibrium carbon dioxide capture and utilization method and a reactor thereof. Technical Background

[0002] Carbon capture, utilization and storage (CCUS) is the most important technical path to address global climate change and control greenhouse gas emissions. my country has promised the world "carbon peak in 2030" and "carbon neutrality in 2060". The Central Economic Work Conference listed it as one of the eight key tasks for 2021. This "new climate goal" will trigger a huge change in my country's energy structure. There are many sources of CO2 emissions in modern industrial production, such as cement, steel, electricity, coal chemical industry and refineries, which are all major CO2 emitters. In response to the problem of CO2 emissions, various industries have conducted research and exploration on the capture, utilization and storage of CO2. Each industry has formed a variety of technical methods for CO2 capture, utilization and storage based on its own industry characteristics.

[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, which causes the energy consumption of coal-fired power plants to increase by about 30%. At the same time, the captured CO2 is stored off-site, which requires high transportation costs, and safety hazards are also questioned. The adsorption method is also relatively mature in technology, but it is generally only used for working conditions with a certain gas composition. The capacity and CO2 selectivity of the adsorbent are low, the cost is high, and it is generally only used for low-temperature gas. The membrane method usually cannot achieve a high degree of separation and requires 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 CO2 gas is obtained, and subsequent transportation and utilization are also issues worthy of attention. The development of CO2 capture and conversion technology into high-value-added chemicals is the key.

[0004] In recent years, with the strong support of the Chinese government, enterprises, scientific research institutions and universities have jointly participated in a series of studies on supporting policies, relevant theories and key technologies, established a professional research team, and achieved a number of results and progress. The specific situation of major domestic industrial pilot and demonstration projects is as follows: The CO2 capture demonstration project launched by Huaneng Group in Shanghai Shidongkou Second Power Plant in December 2009 uses CO2 capture technology with independent intellectual property rights, with an annual CO2 capture scale of 120,000 tons and a captured CO2 purity of more than 99.5%. Part of the captured CO2 is used in the food processing industry after passing through the refining system, and the rest is used in industrial production. When the capture device was put into operation, it was the largest flue gas CO2 capture device in the world for coal-fired power plants. The 250MW IGCC unit of Huaneng Tianjin Green Coal Power was completed and put into operation in 2011, and the 400MW IGCC unit equipped with a CO2 capture device was completed in 2016. The demonstration project aims to research, develop, demonstrate and promote a coal-based power generation system with near-zero CO2 emissions, while significantly improving power generation efficiency and mastering the design, construction and operation technologies of large-scale coal gasification projects.

[0005] Currently, three companies have established pilot demonstrations of calcium cycle CO2 capture, including Spain's La Pereda's 1.7MWth power plant flue gas CO2 capture demonstration system, Germany's Darmstadt's 1MWth power plant flue gas CO2 capture demonstration system, and Taiwan's ITRI Research Institute's 3kWth power plant flue gas CO2 capture pilot. All of them use a calcium cycle double fluidized bed capture system to achieve CO2 capture and regeneration in flue gas.

[0006] All of the above technologies focus on CO2 capture and do not involve conversion and subsequent utilization. The research on CO2 capture and conversion in the published patents is mostly focused on catalysts. Since CO2 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 have some problems in CO2 capture and conversion. On the one hand, with the switching of the capture / conversion process, the coil absorbs heat for a while and takes heat for a while, which makes it difficult to control; 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 combustion heating, there is often a problem of local overheating of the catalyst bed. Taking the commonly used CaO / CaCO3 adsorbent as an example, when the temperature is greater than 850-900℃, the adsorbent will melt and sinter, and the CO2 conversion process generally requires a reaction temperature of more than 500-700℃. If direct supplementary combustion heating is used, the temperature is too high and the adsorbent will melt and 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 need to be supplemented, 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] Chinese patent CN202110287520.5 discloses a method for reducing carbon monoxide synthesis gas with a 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 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] Chinese patent CN201821322948.9 discloses a catalytic reaction device, which has a methane + water vapor hydrogen production catalyst 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 problems of this patent are: first, carbon dioxide hydrogenation is a strong endothermic reaction. Every 5% reaction of equivalent proportions of CO2 and H2 will cause a temperature drop of about 150°C. Under the type of this reactor, the reaction is actually unsustainable and will soon terminate due to the temperature drop; second, the reactor does not involve carbon capture, but is only a carbon dioxide hydrogenation reactor.

[0009] China CN201410202280.4 discloses a method based on manganese and lanthanide metal catalysts to hydrogenate carbon dioxide to produce carbon monoxide by reverse water gas reaction. The main problems of this patent are similar to those of CN201821322948.9. First, the hydrogenation of carbon dioxide is a strong endothermic reaction. Every 5% reaction of equivalent proportions of CO2 and H2 will cause a temperature drop of about 150°C. Under this reactor type, the reaction is actually unsustainable and will soon terminate due to the temperature drop; secondly, this reactor does not involve carbon capture, it is just a carbon dioxide hydrogenation reactor.

[0010] At present, the patents and documents published at home and abroad are concentrated on CO2 capture and CO2 hydrogenation reverse water gas reaction research, while there are few studies on CO2 capture and in-situ conversion. Efficiently capture CO2 at high temperature and convert the captured CO2 into synthesis gas products in situ to facilitate the subsequent synthesis of chemical products such as light olefins with high added value. It can fully improve energy utilization and effectively reduce emission reduction costs, avoid high energy consumption of capture cooling / conversion heating, solve the high cost of purification and transportation of CO2 after capture, and the safety hazards caused by storage, which is expected to improve the feasibility and economy of the entire CO2 emission reduction process, and is of great significance. Summary of the invention

[0011] To solve the above problems, the purpose of the present invention is to provide a self-heating equilibrium carbon dioxide capture and utilization method and a reactor thereof to capture CO2 from high-temperature gas and convert it into synthesis gas in situ in view of the deficiencies of the above-mentioned prior art.

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

[0013] A self-heating equilibrium carbon dioxide capture and utilization method, characterized in that the method comprises the following steps:

[0014] 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 transported through the heat exchange pipe and absorbed by the process gas from the conversion reactor. The decarbonized gas comes out of the adsorption reactor;

[0015] 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 reaction heat generated by the adsorption process in step 1);

[0016] 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. The heat generated during the adsorption reaction is transported through the heat exchange pipe and absorbed by the process gas in the adsorption reactor undergoing the conversion reaction;

[0017] 4) 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 steps are repeated.

[0018] The invention provides a self-heating equilibrium carbon dioxide capture and utilization method, characterized in that the adsorption reaction temperature is between room temperature and 800°C, preferably in the temperature range of 600 to 750°C.

[0019] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization method, characterized in that the conversion reaction temperature is 100-950°C, preferably in the temperature range of 600-800°C.

[0020] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization method, characterized in that: the process gas described in step 1) refers to the reducing gas contained in the conversion reactor to generate synthesis gas.

[0021] The present invention provides a self-heating balance type carbon dioxide capture and utilization method, characterized in that: the heat exchange pipeline includes an adsorption conversion process gas pipeline and a conversion adsorption process gas pipeline, and heat is exchanged between the adsorption reactor and the conversion reactor through the heat exchange pipeline to achieve self-heating balance of the device.

[0022] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization method, characterized in that: the catalyst beds of the adsorption reactor and the conversion reactor are both filled with catalytic materials, and the catalytic materials refer to materials with dual functions of carbon dioxide adsorption and catalytic conversion, such as CaO materials loaded with any one or more metals of active components such as Co, Ni and lanthanide metals.

[0023] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization method, characterized in that: the reducing gas refers to a gas that reacts with CO2 to generate CO, and refers to any one or a mixture of more than one gas among H2, CH4 and C2H6, or a mixture of these gases and an inert gas (such as nitrogen).

[0024] When these gases are introduced separately, the following reactions occur:

[0025] CO2+2H2=CO+H2O+H2 or CO2+H2=CO+H2O

[0026] CO2+CH4=2CO+2H2

[0027] 2CO2+C2H6=4CO+3H2

[0028] 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, both are single or multiple, and the catalyst bed is filled with catalytic materials.

[0029] The present invention also provides a self-heating equilibrium type carbon dioxide capture and utilization device, which is used to implement the above-mentioned self-heating equilibrium type carbon dioxide capture and utilization method, specifically:

[0030] A self-heating equilibrium type carbon dioxide capture and utilization device comprises an adsorption reactor and a conversion reactor, wherein catalyst beds, heat exchange piping and partitions are arranged in the adsorption reactor and the conversion reactor, and the characteristics are as follows: catalytic materials are loaded in the catalyst beds of the adsorption reactor and the conversion reactor, and the catalyst beds are arranged in multiple layers; the heat exchange piping comprises an adsorption conversion process gas piping and a conversion adsorption process gas piping, and heat is exchanged between the adsorption reactor and the conversion reactor through the heat exchange piping to achieve self-heating equilibrium of the device; the partition is arranged between two stages of catalyst beds to isolate the process gas.

[0031] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization device, and its further technical feature is that the reactor is a fixed bed reactor.

[0032] The present invention provides a self-heating balance type carbon dioxide capture and utilization device, which has further technical characteristics: the heat exchange pipe refers to a heat exchange structure such as a heat exchange tube, a plate heat exchanger or a pipe box containing a medium, the heat exchange tube can be a fin tube, a coil or a serpentine tube, etc., and the pipe box can contain a heat exchange component.

[0033] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization device, and its further technical feature is 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, etc.

[0034] The present invention provides a self-heating equilibrium carbon dioxide capture and utilization device, and its further technical feature is that: the adsorption reactor and the conversion reactor can be set up with one or more reactors. When the adsorption reactor and the conversion reactor are set up with multiple reactors, they can be switched at the same time or independently one by one, that is, one adsorption reactor can correspond to multiple conversion reactors, multiple adsorption reactors can correspond to one conversion reactor, or multiple adsorption reactors can correspond to multiple conversion reactors. The specific setting needs to be determined according to the heat matching situation of the adsorption and conversion processes.

[0035] 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:

[0036] A=A1×A3 / A2

[0037] Where: A1 represents the amount of carbon dioxide to be adsorbed;

[0038] A2 represents the adsorption capacity of the material;

[0039] A3 expresses the design switching time.

[0040] 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.

[0041] The present invention is suitable for treating carbon dioxide-containing gas (such as high-temperature flue gas containing CO2, etc.) to capture CO2 from the carbon dioxide-containing gas 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.

[0042] The advantages of the present invention compared with the prior art are:

[0043] 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 energy utilization and effectively reduce emission reduction costs, while avoiding high energy consumption of capture cooling / conversion heating, solving the high cost of purification and transportation of CO2 after capture, as well as the potential safety hazards caused by storage;

[0044] 2) In the reactor of the present invention, since the heat exchange between the conversion process and the adsorption process is carried out continuously and evenly, 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 materials caused by uneven reaction, accidental interruption of the heat exchange medium, etc. in traditional reactors;

[0045] 3) It can realize the in-situ coupled utilization of heat in the adsorption exothermic / conversion endothermic process, saving more than 50% energy compared with existing reactors;

[0046] 4) The reactor has low pressure drop and can be applied to most flue gas conditions;

[0047] 5) The process is simple, easy to operate and maintain, with low investment and small footprint.

[0048] 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

[0049] Figure 1 A schematic diagram of a process flow of a self-heating equilibrium carbon dioxide capture and utilization method of the present invention;

[0050] Figure 2 It is a schematic diagram of the process flow of another self-heating equilibrium carbon dioxide capture and utilization method of the present invention.

[0051] The figures shown therein are marked as: 1-high temperature flue gas containing CO2, 2-gas after decarbonization, 3-reducing gas, 4-synthesis gas, 5-gas pipeline for adsorption conversion process, 6-gas pipeline for conversion adsorption process, 7, 8, 9, 10, 11, 12, 13, 14-control valve, 15-partition, 21-adsorption reactor, 22-conversion reactor, 111-catalytic material in the bed. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings.

[0053] As attached Figure 1 As shown, a self-heating equilibrium carbon dioxide capture and utilization method and device, wherein the number of reactors can be one or more. Figure 1There 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. When the adsorption reaction is performed for the first time, the reducing gas in the conversion reactor absorbs the heat of the adsorption reaction and passes through. After the first adsorption cycle is completed, the conversion regeneration process begins in the adsorption reactor, and the conversion reactor begins to perform the adsorption reaction. From then on, the adsorption reaction and the conversion reaction reach self-heating equilibrium. For the convenience of description, the present invention is described using an adsorption reactor and a conversion reactor.

[0054] The reactor of the present invention can also be multiple, such as the attached Figure 2 As shown. Some reactors are in the adsorption reaction state, and some reactors 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 one by one to reduce the impact of fluctuations on the upstream gas; the reactor can also be a single reactor, and the interior of the reactor can be divided into different functional areas by separating means such as partitions.

[0055] The following is for the convenience of description. Figure 1 Take the two reactors shown as an example. One is an adsorption reactor and the other is a conversion reactor. Before the device starts running, control valves 7 to 14 are all in a closed state. The steps of the self-heating equilibrium carbon dioxide capture and utilization method are:

[0056] 1) Control valves 7 and 11 are opened, and high-temperature flue gas 1 containing CO2 enters the adsorption reactor 21 through the control valve 7. CO2 in the flue gas is adsorbed and captured by the catalytic material in the catalyst bed. A part of the adsorption reaction heat generated by each bed enters the conversion reactor 22 through the adsorption conversion process gas pipe 5, exchanges heat with the process gas for cooling, and then returns to the next catalyst bed. The other part of the heat is taken out by the process gas from the conversion reactor 22 through the conversion adsorption process gas pipe 6. The CO2 gas passes through the adsorption reactor catalyst beds 1#, 2#, and 3# in sequence according to the above steps. The decarbonized gas 2 comes out of the adsorption reactor 21 through the control valve 11. At this time, the adsorption reactor 21 is in an adsorption state, and the adsorption reaction temperature is room temperature to 800°C, preferably in the temperature range of 600 to 750°C. In this step, the partition 15 is used to isolate the material exchange between the two catalyst beds. The adsorption conversion process gas pipe 5 and the conversion adsorption process gas pipe 6 mentioned above can also be the hot side and the cold side of the plate heat exchanger.

[0057] 2) When the adsorption reactor 21 reaches the saturated adsorption capacity of the adsorbent, the control valves 7 and 11 are closed, the control valves 9 and 14 are opened, and the high-temperature flue gas 1 containing CO2 is switched to enter the conversion reactor 22 through the control valve 9. At this time, the control valves 8 and 12 are opened, and the reducing gas 3 enters the adsorption reactor 21 through the control valve 8, and passes through the adsorption reactor bed layers 1#, 2#, and 3# 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 adsorption reaction heat described in step 1) through the adsorption conversion process gas pipe 5 and the conversion adsorption process gas pipe 6. The synthesis gas 4 comes out of the adsorption reactor 21 through the control valve 12. At this time, the adsorption reactor 21 is in a conversion state, and the conversion reaction temperature is 100-950°C, and the preferred temperature range is 600-800°C;

[0058] 3) The high-temperature flue gas containing CO2 entering the conversion reactor 22 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. The heat is exchanged through the adsorption conversion process gas pipe 5 and the conversion adsorption process gas pipe 6. The decarbonized gas 2 comes out of the conversion reactor 22 through the control valve 14;

[0059] 4) When the conversion reactor reaches the saturated adsorption capacity of the adsorbent, the conversion reactor and the adsorption reactor exchange functions, that is, the conversion reactor is used for adsorption reaction, and the adsorption reactor 21 is used for conversion. At this time, control valves 9 and 14 are closed, 7 and 11 are opened, and the CO2-containing high-temperature flue gas 1 is switched to enter the adsorption reactor 21, control valves 8 and 12 are closed, control valves 10 and 13 are opened, and the reducing gas 3 is switched to enter the conversion reactor 22, and the above operation is repeated.

[0060] 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.

[0061] The present invention is further described below in conjunction with specific examples. The examples are only implementation methods of the present invention under certain specific conditions and should not be regarded as limiting the protection content of the present invention.

[0062] Embodiment 1:

[0063] Raw material high temperature flue gas 100000m 3 Take n / h as an example, the flue gas composition is as follows:

[0064]

[0065] The flue gas temperature is 678°C and the flue gas pressure is 10 kPa. The adsorption reactor 21 and the conversion reactor 22 are switched to operate. When the adsorption reactor 21 is in the adsorption state, the conversion reactor 22 is in the conversion regeneration state.

[0066] 1) The control valves 7 and 11 are opened, and the 678°C high temperature flue gas 1 enters the adsorption reactor 21 from the bottom.

[0067] 2) The adsorption reactor 21 is equipped with catalyst beds 1#, 2#, and 3# of CaO-based catalytic material 111, and the catalytic material is loaded with Co active components for catalyzing the reaction of CO2 and H2.

[0068] 3) According to calculations, with a 2-hour switching cycle, each reactor needs to be filled with 3.16 m3 of catalytic material. 3 The exothermic load of the adsorption process reaction is 33.76MW, which is heat exchanged with the process gas in the conversion reactor 22 through the adsorption conversion process gas pipeline 5.

[0069] 4) Control valves 7 and 11 are opened, and the flue gas enters the adsorption reactor 21 through the control valve 7. The high-temperature CO2 gas passes through the catalyst beds 1#, 2#, and 3# in sequence. In the catalyst bed, the CaO in the catalytic adsorption material reacts with CO2 to generate CaCO3. The heat released raises the temperature of the flue gas and the bed. After adsorption in the adsorption reactor 21, the purified flue gas temperature is 727°C and the purified flue gas volume is 71272.5m 3 n / h, after coming out from the top of the adsorption reactor 21, it is sent to the chimney for discharge after heat recovery.

[0070] 5) At the same time, the control valves 10 and 13 are opened, and in another conversion reactor 22, the CaCO3 in the catalytic adsorption material reacts with the introduced excess H2 at 730°C to generate CaO, CO and water, and the required heat is obtained from the adsorption reactor 21 through the adsorption conversion process gas pipe 5 and the conversion adsorption process gas pipe 6.

[0071] 6) The amount of reaction product synthesis gas 4 is 47958.0m 3 n / h, the synthesis gas temperature is 500°C, and it is discharged through the gas outlet of the conversion reactor 22. The expected composition of the synthesis gas is as follows:

[0072] Element composition CO 28.8v％ <![CDATA[H2]]> 43.0v％ <![CDATA[CO2]]> 1.5v％ <![CDATA[H2O]]> 26.7v％ total 100v％

[0073] 7) After 2 hours, hot nitrogen is introduced into the reactor for purging, and control valves 7, 10, 11, and 13 are closed, and valves 8, 9, 12, and 14 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.

[0074] The flue gas treated by this embodiment can reduce CO2 emissions by 303,000 t / a, and produce 246,000 t / a of synthesis gas as a by-product.

Claims

1. A self-heating equilibrium 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 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 transported through the heat exchange pipe and absorbed by the process gas from the conversion reactor. The decarbonized gas comes out of the adsorption reactor; 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 reaction heat generated by the adsorption process in step 1); 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. The heat generated during the adsorption reaction is transported through the heat exchange pipe and absorbed by the process gas in the adsorption reactor undergoing the conversion reaction; 4) 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 steps are repeated.

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

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

4. 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.

5. The method for capturing and utilizing carbon dioxide according to claim 1, characterized in that: The heat exchange pipeline transportation includes the gas pipeline transportation of the adsorption conversion process and the gas pipeline transportation of the conversion adsorption process. The heat exchange between the adsorption reactor and the conversion reactor is carried out through the heat exchange pipeline transportation to achieve the self-heating balance of the device.

6. 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 the catalytic materials refer to materials with dual functions of carbon dioxide adsorption and catalytic conversion.

7. 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, and refers to any one or a mixture of more than one of H2, CH4 and C2H6, or a mixture of these gases with an inert gas.

8. A self-heating equilibrium carbon dioxide capture and utilization device, comprising an adsorption reactor and a conversion reactor, wherein a catalyst bed, heat exchange piping and a partition are arranged in the adsorption reactor and the conversion reactor, characterized in that: Catalytic materials are loaded in the catalyst beds of the adsorption reactor and the conversion reactor, and the catalyst beds are arranged in multiple layers; the heat exchange piping includes an adsorption conversion process gas piping and a conversion adsorption process gas piping, and heat is exchanged between the adsorption reactor and the conversion reactor through the heat exchange piping to achieve self-heating balance of the device; the partition is arranged between the two stages of the catalyst bed to isolate the process gas.

9. The carbon dioxide capture and utilization device according to claim 8, characterized in that: The reactor is a fixed bed reactor.

10. The carbon dioxide capture and utilization device according to claim 8, characterized in that: The heat exchange pipe transport refers to a heat exchange tube, a plate heat exchanger or a pipe box containing a medium, and the heat exchange tube adopts a fin tube, a coil or a serpentine tube type.

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