A method for capturing and converting carbon dioxide into olefins

Abstract

The present invention relates to a method for capturing and converting carbon dioxide into olefins, belonging to the fields of energy, chemical industry, and environmental protection. The method utilizes micro-interface oscillation absorption technology to absorb CO2 in the gas phase via an absorbing liquid. After the reaction, the absorbing liquid droplets are separated into a mixed gas containing 95% CO2 via a micro-cyclone separator. During the reaction, the mixed gas radially passes through a packing placed in a reactor, where it is converted into light olefins by a bed catalyst medium. The reacted olefin mixed gas is discharged into a separator, which completely separates the olefins, H2O, and unreacted CO2 and H2. The method and apparatus have the advantages of high efficiency, corrosion resistance, stable operation, and low loss rate.

Description

Technical Field

[0001] The present invention relates to a method for producing olefins by capturing and converting carbon dioxide, and belongs to the fields of energy, chemical industry and environmental protection. Background Art

[0002] CO2 is the main gas that causes the greenhouse effect. Against the backdrop of global warming, how to reduce CO2 emissions and utilize it as a resource is a major challenge facing mankind. As the world's largest carbon emitter, my country's carbon peak and carbon neutrality have been incorporated into the overall layout of my country's ecological civilization construction and have become a key strategic direction during the "14th Five-Year Plan" period. Low-carbon olefins such as ethylene and propylene are important basic organic chemical raw materials. With the development of the chemical industry, their demand is increasing. Traditional synthesis methods are mainly naphtha cracking and coal-to-methanol preparation, both of which rely on fossil resources. Therefore, the use of CO2 to convert into low-carbon olefins with high added value can not only realize the utilization of CO2 carbon resources, but also play a role in reducing CO2 emissions, which is of great strategic significance. Summary of the Invention

[0003] The purpose of the present invention is to provide a micro-interface oscillation absorption and regeneration technology for deep absorption and conversion of carbon dioxide, and to achieve the regeneration and utilization of the absorption liquid, and to convert the captured carbon dioxide into light olefins through a hydrogenation reaction through microchannel reaction technology, thereby realizing a method for capturing and converting carbon dioxide into olefins.

[0004] The technical solution of the present invention is:

[0005] A method for capturing and converting carbon dioxide to produce olefins, characterized in that it comprises the following steps:

[0006] 1) The dust-laden flue gas and washing water are passed into the micro-interface oscillating water scrubber. The jet is atomized into fine droplets by the swirl shearing effect. The micro-droplet self-revolution coupling in the swirl field is used to induce the micro-interface oscillation process, thereby strengthening the collision and capture process between the micro-droplets and the dust particles, thereby achieving efficient dust removal.

[0007] 2) After dust removal and cooling, the flue gas and lean amine liquid enter the micro-interface oscillation collector. The lean amine liquid micro-droplets and the carbon dioxide in the flue gas are subjected to mass transfer and absorption under the action of the flow field. At the same time, the self-revolution coupling of the amine liquid droplets in the cyclonic field is used to induce the micro-interface oscillation process, thereby accelerating the interface renewal rate and mass transfer rate, and strengthening the absorption and capture of CO2 by the amine liquid.

[0008] 3) After absorbing carbon dioxide, the rich amine liquid is pumped into the amine liquid pump, and then heat-exchanged with the lean amine liquid. Then, it enters the rich amine liquid micro-interface oscillation regenerator from the tangential inlet. At the same time, part of the rich amine liquid is heated to 120°C by the bottom reboiler, and then pumped into the micro-interface oscillation regenerator. The high-temperature rich amine liquid is transformed into micro-droplets under the action of swirl shearing. The high-temperature rich amine liquid micro-droplets and the low-temperature rich amine liquid are regenerated by heat transfer under the action of the flow field. The regenerated lean amine liquid carries a small amount of dust particles. After heat exchange with the rich amine liquid through the plate heat exchanger, it enters the microchannel separator to separate fine particles. The carbon dioxide released by the micro-interface oscillation regeneration of the rich amine liquid is discharged from the overflow port of the micro-interface oscillation regenerator and goes to the subsequent carbon dioxide conversion to olefins module;

[0009] 4) The small amount of amine droplets carried by the regenerated carbon dioxide enter the microcyclone separator for separation of the amine droplets. This process reduces the diameter of the cyclone, increases centrifugal force, and regulates particle sorting to form a mobile interception membrane, improving the separation efficiency of small particles. By regulating the collision and coalescence of droplets, the micro droplets collide and coalesce into large droplets that are easy to separate, thereby enhancing cyclone separation.

[0010] 5) The CO2 flue gas purified in step 4 is heated in a heating furnace together with the H2 / Ar mixture and then enters the equipment from the side of the cross-flow microchannel reactor. Under the action of the catalyst, the CO2 and H2 react to produce H2O and light olefin products. At the same time, the collision, interception, and adsorption of the bed medium are used to separate carbon powder pollutants from the mixture. The reacted olefin mixture is discharged from the center tube inside the reactor and enters the separator for further separation.

[0011] 6) The separator efficiently separates the delivered mixed gas and completely separates olefins, H2O and unreacted CO2, Ar and H2.

[0012] Step 1) The water used in the micro-interface oscillating water washer is recycled at the return input port under the action of a pump.

[0013] In step 2), the flue gas after the removal of carbon dioxide is discharged from the overflow port of the micro-interface oscillation collector and discharged to the chimney; the captured rich amine liquid is discharged from the bottom flow port of the micro-interface oscillation collector and converted into lean amine liquid through step 3) to enter the micro-interface oscillation collector for regeneration and recycling.

[0014] In step 5), the reactor bed can be regenerated. During the regeneration operation, the circumferential feed to the cross-flow microchannel reactor is stopped, and nitrogen (1100 Nm3 / h) is introduced from the bottom of the reactor to cause boiling and fluidization of the packed bed. The fluidized packing particles and the retained carbon powder contaminants enter the three-phase separator at the top of the reactor for cyclonic separation. By applying periodic alternating forces to the carbon powder and other contaminants attached to the packing particles, the contaminants are desorbed and discharged from the reactor through the three-phase separator along with the gas. Simultaneously, the surface-cleaned packing returns to the reactor and self-organizes to form a new packed bed.

[0015] The beneficial effects of the present invention are:

[0016] The present invention absorbs carbon dioxide in waste gas and converts it into olefin energy, and the reaction process is green and pollution-free. The carbon dioxide capture rate and conversion efficiency are high, and the absorption liquid can be recycled and reused. The equipment and internal parts are corrosion-resistant, resistant to fouling and clogging, and operate stably. The entire process is simple to operate, the absorbent dosage and loss rate are low, and the catalyst cycle is long. The present invention has low carbon capture cost, generates olefin energy, and has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0018] The dusty flue gas (280℃) with a carbon dioxide content of about 11.68% was heated at 10000Nm 3 / h flow rate into the upper left port of the micro-interface oscillating water scrubber, and at the same time, the washing water is fed at 80m 3 / h flow rate into the lower left port of the micro-interface oscillation water scrubber, remove dust in the flue gas and reduce the temperature before being discharged from the exhaust port on the top.

[0019] The flue gas after dust removal and cooling is introduced into the carbon dioxide collector from the left. The 45℃ lean amine liquid is introduced into the right at a speed of 80m 3 The flue gas is fed into the CO2 collector at a flow rate of 1 / h. The cyclonic field utilizes the self-revolutionary coupling of amine droplets to induce a micro-interface oscillation process, which absorbs and captures CO2 from the flue gas. The purified flue gas is discharged from the upper outlet of the CO2 collector, and the amine-rich liquid, which has absorbed CO2, is discharged from the lower outlet.

[0020] The rich amine liquid after absorbing carbon dioxide is heated to 55℃ by the power pump A and plate heat exchanger with the lean amine liquid. 3 / h flow rate from the tangential inlet into the micro-interface oscillation regenerator. At the same time, part of the rich amine liquid is heated to 120 ° C by the bottom reboiler, and then pumped into the micro-interface oscillation regenerator for recycling. The high-temperature rich amine liquid droplets and the low-temperature rich amine liquid are regenerated by heat transfer under the action of the flow field. The regenerated lean amine liquid carries a small amount of dust particles. After heat exchange with the rich amine liquid in the plate heat exchanger, the temperature drops to 55 ° C and is heated to 80m 3 The carbon dioxide is then released into the microchannel separator at a flow rate of 1 / h to separate fine particles and finally enter the carbon dioxide collector to capture carbon dioxide. The carbon dioxide released by the microinterface oscillation regenerator is discharged from the overflow port at the top of the microinterface oscillation regenerator.

[0021] The small amount of amine droplets carried by the carbon dioxide obtained after regeneration enters the microcyclone separator for separation of amine droplets. A mixed gas with a carbon dioxide content of 95% is obtained. The CO2 flue gas with a temperature of 90°C and a content of 95% is heated to 400°C in a heating furnace together with a H2 / Ar mixed gas and then enters the radial microchannel reactor from the side. The reaction gas is a CO2+H2 / Ar mixed gas with a molar ratio of CO2:H2=1:(1.0-5.0), and the volume fraction of Ar in the mixed gas is 30%-60%. At a temperature of 200~400°C, a pressure of 1.0~10MPa, and a GHSV of 5000h -1 -15000h -1 Under the influence of the following conditions and the action of the iron-based catalyst (LaFeO3), CO2 and H2 are converted into H2O and light olefin products. At the same time, the collision, interception, and adsorption of the reactor bed medium separates carbon powder pollutants from the mixed gas. The reacted olefin mixed gas is discharged from the center tube inside the reactor and enters the separator for further separation.

[0022] The separator efficiently separates the incoming mixed gas, completely separating olefins, H₂O, and unreacted CO₂, Ar, and H₂. The selectivity of light olefins in the total product range is 40.0%-70.0%. In the radial microchannel reactor, the reactor bed can be regenerated. This regeneration procedure involves stopping the circumferential feed to the cross-flow microchannel reactor and introducing nitrogen (1100 Nm₃ / h) from the bottom of the reactor to fluidize the packed bed. The fluidized packing particles and retained carbon contaminants enter the three-phase separator at the top of the reactor for cyclonic separation. Periodic alternating forces are applied to the carbon contaminants adhering to the packing particles, desorbing them and exiting the reactor with the gas through the three-phase separator. Simultaneously, the surface-cleaned packing returns to the reactor and self-organizes to form a new packed bed.

Claims

1. A method for capturing and converting carbon dioxide into olefins, characterized in that , which includes the following steps: 1) The dust-laden flue gas and washing water are passed into the micro-interface oscillating water scrubber. The jet is atomized into fine droplets by the swirl shearing effect. The micro-droplet self-revolution coupling in the swirl field is used to induce the micro-interface oscillation process, thereby strengthening the collision and capture process between the micro-droplets and the dust particles, thereby achieving efficient dust removal. 2) After dust removal and cooling, the flue gas and lean amine liquid enter the micro-interface oscillation collector. The lean amine liquid micro-droplets and the carbon dioxide in the flue gas are subjected to mass transfer and absorption under the action of the flow field. At the same time, the self-revolution coupling of the amine liquid droplets in the cyclonic field is used to induce the micro-interface oscillation process, thereby accelerating the interface renewal rate and mass transfer rate, and strengthening the absorption and capture of CO2 by the amine liquid. 3) After absorbing carbon dioxide, the rich amine liquid is pumped and, after heat exchange with the lean amine liquid, enters the rich amine liquid micro-interface oscillation regenerator from the tangential inlet. At the same time, part of the rich amine liquid is heated to 120°C by the bottom reboiler and then pumped into the micro-interface oscillation regenerator. The high-temperature rich amine liquid is transformed into micro-droplets under the action of swirl shearing. The high-temperature rich amine liquid micro-droplets and the low-temperature rich amine liquid are regenerated by heat transfer under the action of the flow field. The regenerated lean amine liquid carries a small amount of dust particles and, after heat exchange with the rich amine liquid in the plate heat exchanger, enters the microchannel separator to separate fine particles. The carbon dioxide released by the rich amine liquid micro-interface oscillation regeneration is discharged from the overflow port of the micro-interface oscillation regenerator and goes to the subsequent carbon dioxide conversion to olefins module. 4) The small amount of amine droplets carried by the carbon dioxide obtained after regeneration enters the microcyclone separator for separation of amine droplets. This process reduces the diameter of the cyclone, increases the centrifugal force, and forms a mobile interception membrane by regulating the particle sorting, thereby improving the separation efficiency of small particles. By regulating the collision and coalescence of droplets, the micro droplets collide and coalesce into large droplets that are easy to separate, thereby enhancing the cyclone separation. 5) The CO2 flue gas purified in step 4 is heated to 400°C in a heating furnace together with the H2 / Ar mixed gas and then enters the equipment from the side of the cross-flow microchannel reactor. Under the action of the catalyst, the CO2 and H2 are converted into H2O and light olefin products. At the same time, the carbon powder pollutants in the mixed gas are separated by the collision, interception and adsorption of the reactor bed medium. The olefin mixed gas after the reaction is discharged from the central tube inside the reactor and enters the separator for further separation. 6) The separator efficiently separates the delivered mixed gas and completely separates olefins, H2O and unreacted CO2, Ar and H2.

2. The method for capturing and converting carbon dioxide into olefins according to claim 1, wherein: The water used in the micro-interface oscillating water washer described in step 1 is returned to the input port for recycling under the action of the pump.

3. The method for capturing and converting carbon dioxide into olefins according to claim 1, wherein: The flue gas after carbon dioxide removal in step 2 is discharged from the overflow port of the micro-interface oscillation collector and discharged to the chimney; the captured rich amine liquid is discharged from the bottom flow port of the micro-interface oscillation collector, converted into lean amine liquid through step 3 and enters the micro-interface oscillation collector for regeneration and recycling.

4. The method for capturing and converting carbon dioxide into olefins according to claim 1, wherein: The reactor bed described in step 5 can be regenerated, and the process is as follows: stop the circumferential feeding of the cross-flow microchannel reactor, introduce nitrogen from the bottom of the reactor to make the packed bed boil and fluidize, and the fluidized packing particles and the retained carbon powder pollutants enter the three-phase separator at the top of the reactor for cyclone separation. Relying on the self-revolutionary coupled motion of the packing particles in the cyclone field, a periodic alternating force is applied to the carbon powder pollutants attached to the packing particles, so that the pollutants are desorbed and discharged from the reactor through the three-phase separator along with the gas; at the same time, the surface-purified packing returns to the reactor and self-organizes to form a new packing bed.

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