Method for adsorbing carbon dioxide based on fluidized bed reaction equipment

Abstract

The invention provides a method for adsorbing carbon dioxide based on fluidized bed reaction equipment, and belongs to the field of flue gas after-treatment. The invention provides a fluidized bed which comprises a fluidized bed upper section 1, a fluidized bed middle section 2 and a fluidized bed lower section 4 from top to bottom, the size of the fluidized bed lower section 4 in the horizontal direction is smaller than that of the top of the fluidized bed upper section 1 in the horizontal direction. A three-section reaction area of a fluidized bed is arranged, so that the problem that the contact time of particles and gas is short is solved, and meanwhile, the capture efficiency of carbon dioxide in flue gas is improved; carbon-containing flue gas enters the fluidized bed and firstly undergoes a first decarburization reaction with adsorbent particles in a lower-section area; then the flue gas enters the middle section area to be subjected to secondary decarburization reaction with the adsorbent particles, and finally, the flue gas speed is reduced by changing the size of the fluidized bed reactor in the upper section area, so that the adsorbent particles can be separated from the flue gas and return to the middle section reaction area by virtue of gravity; meanwhile, the third decarburization reaction of the flue gas and the newly added adsorbent particles is completed.

Description

TECHNICAL FIELD

[0002] The present application relates to the field of flue gas post-processing, in particular to a method for adsorbing carbon dioxide based on a fluidized bed reaction device. BACKGROUND

[0003] Industrial flue gas is the main source of carbon dioxide emissions, and the research and development of its treatment technology has attracted unprecedented attention and attention in the field of environmental protection. Among many gas separation technologies, CO2 capture technology based on solid adsorbent has become an important direction for the development of current carbon capture, utilization and storage (CCUS) technology due to its low energy consumption, no corrosion and no secondary pollution.

[0004] In the CO2 capture process of solid adsorbent, the reactor design is a key factor affecting the capture efficiency. The currently used reactor types include fast fluidized bed and bubbling fluidized bed. Fast fluidized bed is widely studied due to its high circulating flow rate, small gas-solid back mixing and other advantages. However, due to the high operating gas velocity, the gas-solid contact time is short, and the CO2 capture efficiency is not high (especially when dealing with low concentration CO2 flue gas). SUMMARY

[0005] The present application provides a method for adsorbing carbon dioxide based on a fluidized bed reaction device, and the fluidized bed of the present application improves the capture rate of carbon dioxide.

[0006] The present application provides a fluidized bed, which comprises, from top to bottom, a fluidized bed upper section 1, a fluidized bed middle section 2 and a fluidized bed lower section 4. The horizontal size of the fluidized bed lower section 4 is less than the horizontal size of the top of the fluidized bed upper section 1.

[0007] Preferably, the bottom of the fluidized bed lower section 4 is provided with a gas distributor B5. A gas distributor A26 is arranged at the connection between the fluidized bed middle section 2 and the fluidized bed lower section 4. The fluidized bed middle section 2 and the fluidized bed lower section 4 are also connected by a flow guide pipe 3 for guiding the adsorbent particles in the fluidized bed middle section 2 into the fluidized bed lower section 4.

[0008] Preferably, the horizontal size of the fluidized bed lower section 4 is 50% of the horizontal size of the top of the fluidized bed upper section 1. The horizontal size of the fluidized bed middle section 2 is 90% of the horizontal size of the fluidized bed lower section 4.

[0009] The present application also provides an adsorption device, which comprises, from top to bottom, a regenerator, a cooler, the fluidized bed of the above technical solution, a preheater and a conveying bin connected in sequence. The cooler and the preheater are connected to circulate the gas in the cooler and the preheater. The bottom of the conveying bin is also connected with the regenerator.

[0010] Preferably, it further comprises a cyclone separator 10 connected with the fluidized bed, the inlet of the cyclone separator 10 is connected with the outlet of the upper section 1 of the fluidized bed, the bottom outlet of the cyclone separator 10 is connected with the middle section 2 of the fluidized bed. A bag filter 17 connected with the cyclone separator 10; A flue gas separation cylinder 19 connected with the bag filter 17; A fan A 16 connected with the flue gas separation cylinder 19; The flue gas separation cylinder 19 is also connected with the bottom of the cooler through a fan B 18; The fan A 16 is connected with the top end of the cooler; A dust collector 25 connected with the regenerator; A heat exchanger 24 connected with the dust collector 25; A condensing separation tank 23 connected with the heat exchanger 24; A separation cylinder 22 connected with the condensing separation tank 23; The separation cylinder 22 is also connected with the bottom of the regenerator and the top of the conveying bin through a compressor 21 respectively; A fan C 20 connected with the fluidized bed.

[0011] Preferably, the preheater comprises a preheater A 6 and a preheater B 7; The conveying bin comprises a conveying bin A 8 and a conveying bin B 9; The cooler comprises a cooler A 11 and a cooler B 12; The regenerator comprises a regenerator A 13 and a regenerator B 14.

[0012] The application also provides a method for capturing carbon dioxide, which is performed in the adsorption equipment described in the above technical solution, and comprises the following steps: (1) passing flue gas containing carbon dioxide into the lower section 4 of the fluidized bed filled with adsorbent particles, the middle section 2 of the fluidized bed filled with adsorbent particles and the upper section 1 of the fluidized bed filled with adsorbent particles to sequentially react with the adsorbent particles therein to carry out decarburization, obtaining fourth state flue gas in the upper section 1 of the fluidized bed and adsorbent particles adsorbing carbon dioxide in the lower section 4 of the fluidized bed, the middle section 2 of the fluidized bed and the upper section 1 of the fluidized bed; (2) flowing the adsorbent particles adsorbing carbon dioxide obtained in the lower section 4 of the fluidized bed into a preheater to be preheated, into a conveying bin to be sent into a regenerator to be regenerated, and obtaining regenerated adsorbent particles; The regenerated adsorbent particles are sent into a cooler to be cooled and then are passed into the upper section 1 of the fluidized bed to repeatedly perform steps (1) and (2).

[0013] The application also provides a method for capturing carbon dioxide, characterized in that the method is performed in the adsorption equipment as described above, and comprises the following steps: (1) passing flue gas containing carbon dioxide through a fan C20 to be pressurized and through a gas distributor B5 to enter a lower section 4 of a fluidized bed filled with adsorbent particles to perform adsorption, to obtain second-state flue gas and fourth-state adsorbent particles; passing the second-state flue gas into a middle section 2 of the fluidized bed filled with adsorbent particles to perform adsorption, to obtain third-state flue gas and third-state adsorbent particles; passing the third-state flue gas into an upper section 1 of the fluidized bed filled with adsorbent particles to perform adsorption, to obtain fourth-state flue gas and first-state adsorbent particles; (2) passing the fourth-state flue gas into a cyclone separator 10 to perform separation, to obtain separated adsorbent particles and separated flue gas; returning the separated adsorbent particles to a reaction area of the middle section 2 of the fluidized bed for recycling, and passing the separated flue gas into a bag-type dust collector 17 to perform dust removal, to obtain clean flue gas; passing part of the clean flue gas through a flue gas distribution cylinder 19 to obtain part of the re-distributed flue gas, pressurizing the part of the re-distributed flue gas through a fan A16, and recycling the part of the re-distributed flue gas in a cooler and a preheater; guiding the fourth-state adsorbent particles to the preheater, preheating the fourth-state adsorbent particles by hot flue gas obtained from a heat exchange process of the cooler, and then flowing the obtained preheated fourth-state adsorbent particles into a conveying bin and conveying the fourth-state adsorbent particles to a regenerator to perform a desorption reaction under the action of superheated steam, to obtain regenerated adsorbent particles and mixed gas containing water vapor and carbon dioxide; (3) passing the mixed gas into a dust collector C25 to perform dust removal, and then passing the obtained clean mixed gas into a heat exchanger 24 to perform heat exchange, to obtain heat-exchanged mixed gas; passing the heat-exchanged mixed gas into a condensation separation tank 23 to perform condensation, to obtain condensed water and carbon dioxide; passing the carbon dioxide into a gas distribution cylinder 22, pressurizing part of the carbon dioxide through a compressor 21 to be used as regenerator fluidizing gas and conveying gas used by the conveying bin, and conveying the remaining carbon dioxide to a gas storage tank as a product; (4) flowing the regenerated adsorbent particles into the cooler, and then mixing the regenerated adsorbent particles with part of the re-distributed flue gas entering the cooler through the fan A16 preheater and part of the clean flue gas entering the cooler through the fan B18 to perform cooling, and then passing the obtained flue gas after being heated into the preheater to perform heat exchange with the fourth-state adsorbent particles, and then returning the flue gas after being cooled to the cooler to absorb heat, until the fourth-state adsorbent particles are cooled to a target value, and then passing the flue gas after being cooled and the flue gas circulating in the cooler and the heat exchanger into the flue gas distribution cylinder 19, and conveying the regenerated adsorbent particles after being cooled into the reaction area of the upper section 1 of the fluidized bed for recycling.

[0014] Preferably, the flow rate of the flue gas after pressurization by the fan C20 is 15000 Nm 3 / h; The temperature of the flue gas is 70 DEG C, and the pressure of the flue gas is 2 kPaG; The volume fraction of CO2 in the flue gas is 10-14%, the volume fraction of O2 is 5-11%, the volume fraction of H2O is 10-14%, the concentration of SO2 is 10 mg / Nm 3 , the concentration of NO X is 50 mg / Nm 3 , and the concentration of dust is 5 mg / Nm 3 ; the remaining gas of the flue gas is nitrogen.

[0015] Preferably, the adsorbent comprises an active component and a carrier supporting the active component; the active component comprises potassium carbonate; The carrier comprises Al2O3, ZrO2, TiO2 or activated carbon; The pressure of the superheated steam is 1.6 MPa, and the temperature is 255 DEG C.

[0016] The three-stage reaction region of the fluidized bed is set up to solve the problem of short contact time of particles and gas, and to improve the capture efficiency of carbon dioxide in the flue gas: the carbon-containing flue gas enters the fluidized bed and firstly reacts with the adsorbent particles in the lower region to generate the first decarburization reaction, then the flue gas enters the middle region to react with the adsorbent particles again to generate the second decarburization reaction, and finally in the upper region, the size of the fluidized bed reactor is changed to reduce the flue gas speed, so that the adsorbent particles can be separated from the flue gas and return to the middle reaction region by gravity, and at the same time, the third decarburization reaction of the flue gas and the newly added adsorbent particles is completed.

[0017] The equipment of the regeneration process is split into a regenerator, a cooler and a preheater in the application, and the height of different equipment is set to promote the movement of particles between different equipment by gravity and the heat transfer of the medium, so as to solve the problems of material circulation and controllable residence time of adsorbent particles in different states between different equipment and heat recovery and utilization. In the preheater and the cooler, the same circulating flue gas is used as the heat-carrying medium and the fluidizing gas, so that the heat of the high-temperature adsorbent particles in the cooler is recovered and used for heating the low-temperature adsorbent particles in the preheater, thereby reducing the energy consumption of the adsorption process.

[0018] Carbon dioxide gas is introduced into the regenerator as the fluidizing gas and the blowing gas in the application, so as to solve the problem that the gas generated in the regeneration process of saturated adsorbent particles is accumulated in the gap between the particles, thereby reducing the regeneration efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1Structure diagram of the adsorption equipment used in the embodiment. DETAILED DESCRIPTION

[0020] The fluidized bed comprises, from top to bottom, a fluidized bed upper section 1, a fluidized bed middle section 2 and a fluidized bed lower section 4. The horizontal size of the fluidized bed lower section 4 is less than the horizontal size of the top of the fluidized bed upper section 1.

[0021] The fluidized bed provided by the present application comprises a fluidized bed upper section 1. The fluidized bed provided by the present application comprises a fluidized bed middle section 2 below the fluidized bed upper section 1 and connected to the fluidized bed upper section 1. The fluidized bed provided by the present application comprises a fluidized bed lower section 4 below the fluidized bed middle section 2 and connected to the fluidized bed middle section 2. In the present application, the horizontal size of the fluidized bed lower section 4 is less than the horizontal size of the top of the fluidized bed upper section 1, and the horizontal size of the fluidized bed lower section 4 is 50% of the horizontal size of the top of the fluidized bed upper section 1; the horizontal size of the bottom of the fluidized bed upper section 1 is the same as the horizontal size of the fluidized bed middle section 2; and the horizontal size of the fluidized bed middle section 2 is preferably 90% of the horizontal size of the fluidized bed lower section 4.

[0022] In one embodiment of the present application, the bottom of the fluidized bed lower section 4 is provided with a gas distributor B5; and the connection between the fluidized bed middle section 2 and the fluidized bed lower section 4 is provided with a gas distributor A26.

[0023] In one embodiment of the present application, the fluidized bed middle section 2 and the fluidized bed lower section 4 are further connected by a flow guide pipe 3 for guiding the adsorbent particles in the fluidized bed middle section 2 into the fluidized bed lower section 4.

[0024] The present application further provides an adsorption equipment comprising, from top to bottom, a regenerator, a cooler, a fluidized bed, a preheater and a conveying bin connected in sequence. The cooler and the preheater are connected to circulate the gas in the cooler and the preheater. The bottom of the conveying bin is further connected to the regenerator.

[0025] The adsorption equipment provided by the present application comprises a regenerator.

[0026] In one embodiment of the present application, the regenerator comprises a regenerator A13 and a regenerator B14.

[0027] In one embodiment of the present application, the adsorption equipment provided by the present application further comprises a dust remover C25 connected to the regenerator, a heat exchanger 24 connected to the dust remover C5, a condensing separation tank 23 connected to the heat exchanger 24 and a carbon dioxide gas separation cylinder 22 connected to the condensing separation tank 23.

[0028] In one embodiment of the present application, the carbon dioxide gas cylinder 22 is also connected to the bottom of the regenerator and the top of the conveying bin, respectively, through the compressor 21.

[0029] The present application provides an adsorption device comprising a cooler below and connected to the regenerator.

[0030] In one embodiment of the present application, the cooler comprises cooler A11 and cooler B12.

[0031] The present application provides an adsorption device comprising a fluidized bed below and connected to the cooler.

[0032] In one embodiment of the present application, the adsorption device provided by the present application further comprises: a cyclone separator 10 connected to the fluidized bed; the inlet of the cyclone separator 10 is connected to the outlet of the upper section 1 of the fluidized bed; the bottom outlet of the cyclone separator 10 is connected to the middle section 2 of the fluidized bed.

[0033] In one embodiment of the present application, the adsorption device provided by the present application further comprises: a bag-type dust collector 17 connected to the cyclone separator 10; a flue gas cylinder 19 connected to the bag-type dust collector 17; a fan A16 connected to the flue gas cylinder 19.

[0034] In one embodiment of the present application, the fan A16 is connected to the top end of the cooler.

[0035] In one embodiment of the present application, the flue gas cylinder 19 is also connected to the bottom of the cooler through the fan B18.

[0036] The present application provides an adsorption device comprising a preheater below and connected to the fluidized bed.

[0037] In one embodiment of the present application, the preheater comprises preheater A6 and preheater B7.

[0038] The present application provides an adsorption device comprising a conveying bin below and connected to the preheater.

[0039] In one embodiment of the present application, the conveying bin comprises conveying bin A8 and conveying bin B9. In one embodiment of the present application, the adsorption device provided by the present application further comprises: a fan C20 connected to the fluidized bed.

[0040] The present application also provides a method for capturing carbon dioxide, which is carried out in the adsorption device described in the above technical solution, comprising the following steps: (1) the flue gas containing carbon dioxide is sequentially subjected to decarburization reaction with the adsorbent particles in the lower section 4 of the fluidized bed filled with adsorbent particles, the middle section 2 of the fluidized bed filled with adsorbent particles and the upper section 1 of the fluidized bed filled with adsorbent particles, and the fourth state flue gas is obtained in the upper section 1 of the fluidized bed, and the adsorbent particles adsorbing carbon dioxide are obtained in the lower section 4 of the fluidized bed, the middle section 2 of the fluidized bed and the upper section 1 of the fluidized bed; (2) the adsorbent particles adsorbing carbon dioxide obtained in the lower section 4 of the fluidized bed are flowed into the preheater for preheating, sent into the conveying bin and then into the regenerator for regeneration, and the regenerated adsorbent particles are obtained; the regenerated adsorbent particles are sent into the cooler for cooling and then flowed into the upper section 1 of the fluidized bed for repeatedly performing steps (1) and (2).

[0041] The application further provides a method for capturing carbon dioxide, which is performed in the adsorption equipment as described in the above technical solution and comprises the following steps: (1) the flue gas containing carbon dioxide is subjected to adsorption in the lower section 4 of the fluidized bed filled with adsorbent particles after being pressurized by the fan C20 and passing through the gas distributor B5, and the second state flue gas and the fourth state adsorbent particles are obtained; the second state flue gas is subjected to adsorption in the middle section 2 of the fluidized bed filled with adsorbent particles, and the third state flue gas and the third state adsorbent particles are obtained; the third state flue gas is subjected to adsorption in the upper section 1 of the fluidized bed filled with adsorbent particles, and the fourth state flue gas and the first state adsorbent particles are obtained; (2) the fourth state flue gas is subjected to separation in the cyclone separator 10, and the separated adsorbent particles and the separated flue gas are obtained; the separated adsorbent particles are returned to the reaction area of the middle section 2 of the fluidized bed for recycling, and the separated flue gas is subjected to dust removal in the bag-type dust collector 17, and the clean flue gas is obtained; part of the clean flue gas obtained by the flue gas distribution cylinder 19 is pressurized by the fan 16 and then recycled in the cooler and the preheater; the fourth state adsorbent particles are preheated by the hot flue gas obtained from the heat exchange process of the cooler, then flowed into the conveying bin and then conveyed to the regenerator, and subjected to desorption reaction under the action of superheated steam, and the regenerated adsorbent particles and the mixed gas containing water vapor and carbon dioxide are obtained; (3) the mixed gas is subjected to dust removal in the dust collector 25, and then subjected to heat exchange in the heat exchanger 24, and the heat exchanged mixed gas is obtained; the clean mixed gas is subjected to condensation in the condensation separation tank 23, and the condensed water and carbon dioxide are obtained; The carbon dioxide is introduced into the gas cylinder 22, and then the obtained partial carbon dioxide is pressurized by the compressor 21 and used as a regenerator fluidizing gas and a conveying gas for the conveying chamber, and the remaining carbon dioxide is conveyed to the gas storage tank as a product; (4) The regenerated adsorbent particles are flowed into the cooler, and then mixed with the partial flue gas cooled by the preheater through the fan A16 and the partial flue gas cooled by the cooler through the fan B18, and then cooled, and then the obtained heated flue gas is introduced into the preheater to exchange heat with the fourth state adsorbent particles, and then the obtained cooled flue gas is returned to the cooler to absorb heat, until the fourth state adsorbent particles are cooled to the target value, and then the cooled regenerated adsorbent particles are sent to the upper section 1 of the fluidized bed to circulate in the reaction area.

[0042] In the present application, the flue gas is pressurized by the fan C20 and then introduced into the lower section 4 of the fluidized bed containing the adsorbent particles through the gas distributor B5 to be adsorbed, and the second state flue gas and the fourth state adsorbent particles are obtained. In the present application, the flow rate of the flue gas pressurized by the fan C20 is preferably 15000 Nm 3 / h; The temperature of the flue gas is preferably 70℃, and the pressure of the flue gas is preferably 2kPaG; The volume fraction of CO2 in the flue gas is 10~14%, the volume fraction of O2 is 5~11%, the volume fraction of H2O is 10~14%, the concentration of SO2 is 10mg / Nm 3 , the concentration of NO X is 50 mg / Nm 3 , and the concentration of dust is 5mg / Nm 3 ; and the remaining gas in the flue gas is nitrogen.

[0043] In the present application, the adsorbent includes an active component and a carrier loaded with the active component; the active component includes potassium carbonate; and the carrier includes Al2O3, ZrO2, TiO2 or activated carbon.

[0044] After obtaining the second state flue gas, the second state flue gas is introduced into the middle section 2 of the fluidized bed containing the adsorbent particles to be adsorbed, and the third state flue gas and the third state adsorbent particles are obtained.

[0045] The adsorbent particles in the middle section 2 of the fluidized bed preferably include the second state adsorbent particles. The second state adsorbent particles fall into the middle section 2 of the fluidized bed under the action of gravity.

[0046] After obtaining the third state flue gas, the third state flue gas is introduced into the upper section 1 of the fluidized bed filled with adsorbent particles for adsorption, to obtain fourth state flue gas and first state adsorbent particles.

[0047] In the present application, the adsorbent particles in the upper section 1 of the fluidized bed include fresh adsorbent particles or first state adsorbent particles after desorption.

[0048] After obtaining the fourth state flue gas, the present application introduces the fourth state flue gas into the cyclone separator 10 for separation, to obtain separated adsorbent particles and separated flue gas.

[0049] After obtaining the separated adsorbent particles, the present application returns the separated adsorbent particles to the reaction area of the middle section 2 of the fluidized bed for recycling, and introduces the separated flue gas into the bag filter 17 for dust removal, to obtain clean flue gas.

[0050] After obtaining the clean flue gas, the present application circulates part of the clean flue gas obtained after the clean flue gas passes through the flue gas distribution cylinder 19 through the fan 16 for pressurization, and then through the cooler and the preheater.

[0051] After obtaining the fourth state adsorbent particles, the present application guides the fourth state adsorbent particles to the preheater, and then preheats the fourth state adsorbent particles by the hot flue gas obtained from the heat exchange process of the cooler, and then flows the obtained preheated fourth state adsorbent particles into the conveying bin and then to the regenerator for desorption reaction under the action of superheated steam, to obtain regenerated adsorbent particles and mixed gas containing water vapor and carbon dioxide.

[0052] In the present application, the preheated temperature of the preheated fourth state adsorbent particles is preferably 135℃.

[0053] In the present application, the pressure of the superheated steam is preferably 1.6MPa, and the temperature is preferably 255℃.

[0054] In the present application, the temperature of the desorption reaction is preferably ≥250℃. The fourth state adsorbent particles are regenerated by the desorption reaction.

[0055] After obtaining the mixed gas containing water vapor and carbon dioxide, the present application introduces the mixed gas into the dust remover 25 for dust removal, and then introduces the obtained clean mixed gas into the heat exchanger 24 for heat exchange, to obtain heat exchanged mixed gas.

[0056] After obtaining the condensed water and carbon dioxide, the present application pressurizes part of the obtained carbon dioxide by the compressor 21, and then uses the pressurized carbon dioxide as the fluidizing gas of the regenerator and the conveying gas of the conveying bin, respectively, and the remaining carbon dioxide is delivered to the gas storage tank as a product.

[0057] In the present application, the condensed water is preferably introduced into the circulating cooling water system of the heat exchanger 24.

[0058] After obtaining the regenerated adsorbent particles, the present application flows the regenerated adsorbent particles into the cooler to be mixed with the part of the flue gas that is redistributed after being preheated by the fan A16 and enters the cooler, and the part of the flue gas that enters the cooler by the fan B18, to be cooled, and then the obtained flue gas that is heated is introduced into the preheater to exchange heat with the fourth state adsorbent particles, and then the obtained flue gas that is cooled is returned to the cooler to absorb heat, until the fourth state adsorbent particles are cooled to the target value, and then the flue gas that is cooled and the flue gas that circulates in the cooler and the heat exchanger is introduced into the flue gas distribution cylinder 19, and the regenerated adsorbent particles that are cooled are sent to the upper section 1 of the fluidized bed reaction area for recycling.

[0059] In the present application, the flue gas that circulates in the cooler and the heat exchanger is preferably introduced into the flue gas distribution cylinder 19 by the fan A16.

[0060] In the present application, the temperature of the regenerated adsorbent particles after being mixed with the part of the flue gas that is redistributed after being preheated by the fan A16 and enters the cooler to be cooled is preferably 150°C, and the temperature of the part of the flue gas that enters the cooler by the fan B18 to be cooled is preferably 70°C.

[0061] The method for adsorbing carbon dioxide based on the fluidized bed reaction equipment provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.

[0062] Figure 1 The structure of the adsorption equipment used in the examples is shown in the schematic diagram: 1. upper section of the fluidized bed; 2. middle section of the fluidized bed; 3. flow guide pipe; 4. lower section of the fluidized bed; 5. gas distributor B; 6. preheater A; 7. preheater B; 8. conveying bin A; 9. conveying bin B; 10. cyclone separator; 11. cooler A; 12. cooler B; 13. regenerator A; 14. regenerator B; 15. dust remover A; 16. fan A; 17. dust remover B; 18. fan B; 19. flue gas distribution cylinder; 20. fan C; 21. compressor; 22. carbon dioxide distribution cylinder; 23. condensation separation tank; 24. heat exchanger; 25. dust remover C; 26. gas distributor A. Among them, the horizontal size of the lower section of the fluidized bed 4 is 50% of the horizontal size of the top of the upper section of the fluidized bed 1; the horizontal size of the middle section of the fluidized bed 2 is 90% of the horizontal size of the lower section of the fluidized bed 4.

[0063] Example 1 Flue gas flow: 15000 Nm 3 / h; Flue gas temperature: 70°C; Flue gas pressure: 2 kPa G Flue gas composition (vol %): CO2: 12%; O2: 8%; H2O: 12%; the rest is N2; SO2: 10 mg / Nm 3 ; NO X : 50 mg / Nm 3 ; Dust content: 5 mg / Nm 3 ; Solid adsorbent dosage: 272 t; 1.6 MPa superheated steam (255°C) dosage: 35 t / h; adsorbent is Al2O3 loaded with potassium carbonate; Circulating cooling water (32°C) dosage: 250 t / h; Implementation process: The first state flue gas (flue gas containing carbon dioxide) from the pipe network 15000 Nm 3 / h is pressurized to 80 kPaG by fan C20 and enters the gas distributor B5 at the bottom of the fluidized bed as fluidizing gas and raw material gas, and reacts with adsorbent particles of different states in the fluidized bed to remove carbon. The fluidized bed is divided into three reaction zones: upper, middle and lower. The first state flue gas enters the lower section 4 reaction zone, first reacts with the third state adsorbent particles flowing from the middle section 2 reaction zone to obtain the second state flue gas, then enters the middle section 2 reaction zone and reacts with the third state adsorbent particles to obtain the third state flue gas, and finally enters the upper section 1 reaction zone of the fluidized bed and reacts with fresh or desorbed first state adsorbent particles to obtain the fourth state flue gas. The fourth state flue gas leaves the upper section 1 reaction zone of the fluidized bed, enters the cyclone separator 10 and the bag filter 17 in turn for dust removal and collects solid particles, respectively. The solid particles collected by the cyclone separator 10 are directly returned to the middle section 2 reaction zone of the fluidized bed for circulation, the adsorbent particles collected by the bag filter 17 are discharged outside the system, and the clean flue gas obtained by dust removal enters the flue gas distribution cylinder 19. Part of the clean flue gas is pressurized by fan 16 and circulated in cooler 12 and preheater 7 as fluidizing gas, and the other part of the clean flue gas is pressurized by the induced draft fan to 2 kPa and directly discharged outside the system into the pipe network.

[0064] During normal operation, both coolers 11 and 12 are in working condition at the same time. The cooler 11 stores fresh or desorbed particles which have been cooled to the first state of adsorbent particles and cooperates with the feed control valve to achieve uniform feeding of solid adsorbent, with a feeding speed of 68 t / h. The cooler 12 receives high-temperature adsorbent particles discharged from the regenerator 14 and then performs stepwise cooling to 65℃. The fresh or desorbed first state adsorbent particles are added to the upper section 1 reaction zone of the fluidized bed, and decarburization occurs between the adsorbent particles and the third state flue gas to obtain second state adsorbent particles. The second state adsorbent particles fall into the middle section 2 reaction zone of the fluidized bed under the action of gravity, and decarburization occurs between the adsorbent particles and the second state flue gas to obtain third state adsorbent particles. Then the third state adsorbent particles enter the lower section 4 reaction zone through the flow guide pipe 3 (material flow rate 68 t / h) and decarburization occurs again between the adsorbent particles and the first state flue gas to obtain fourth state adsorbent particles.

[0065] The fourth state adsorbent particles are selectively guided (material flow rate 68 t / h) into the preheater 7, and this part of the particles is preheated to 135℃ by the hot flue gas obtained from the heat exchange process of the cooler 12. Then the preheated adsorbent particles enter the conveying bin 9 and are conveyed to the regenerator 14 by carbon dioxide gas, and are indirectly heated to 250℃ by superheated steam and undergo regeneration reaction. The desorbed carbon dioxide and water vapor mixed gas in the regeneration reaction process is carried into the bag filter 25 by the fluidizing gas carbon dioxide, and then enters the heat exchanger 24 after dust removal to be cooled to 30℃. The condensed water in the mixed gas is separated in the condensing separation tank 23 and enters the circulating cooling water system. The carbon dioxide in the mixed gas enters the gas separation cylinder 22, and a part of the carbon dioxide is pressurized to 0.6 MPa by the compressor 21 and used as conveying gas for the conveying bin 9. Another part of the carbon dioxide is pressurized to 2 kPa by the fan and discharged outside the area to enter the pipe network.

[0066] The adsorbent particles discharged from the regenerator 14 enter the cooler 12 and exchange heat with the circulating clean flue gas (total flue gas 16000 Nm 3 / h) as the heat carrying medium to be cooled to about 135℃. Then the low-temperature clean flue gas (flue gas flow rate 11400 Nm 3 / h) after dust removal by the bag filter 17 is directly introduced into the cooler 11 / 12 by the fan 18 to continue cooling the adsorbent particles, until the adsorbent particles are cooled to about 70℃. Then the adsorbent particles are sent to the upper section 1 reaction zone of the fluidized bed as first state adsorbent particles for recycling.

[0067] The 16000Nm3 of net flue gas as heat carrier medium is introduced from the flue gas distribution cylinder 19, pressurized by the fan 16, circulated between the cooler 12 and the preheater 7, heated in the cooler 12, exchanged heat with the fourth state adsorbent particles in the preheater 7, then the cooled net flue gas returns to the cooler 12 to absorb heat, until the fourth state adsorbent particles are preheated to 135℃, then the net flue gas is sent into the flue gas distribution cylinder 19.

[0068] Results: Carbon dioxide product purity: ≥95%; Carbon dioxide flow: 3.3t / h; Net flue gas flow: 11400Nm3 / h.

[0069] The above only describes the preferred embodiments of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make several improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A fluidized bed characterized in that, It comprises, from top to bottom, a fluidized bed upper section (1), a fluidized bed middle section (2) and a fluidized bed lower section (4); The horizontal dimension of the fluidized bed lower section (4) is less than the horizontal dimension of the top of the fluidized bed upper section (1).

2. Fluidized bed according to claim 1, characterized in that The bottom of the fluidized bed lower section (4) is provided with a gas distributor B (5); The connection between the fluidized bed middle section (2) and the fluidized bed lower section (4) is provided with a gas distributor A (26); The fluidized bed middle section (2) and the fluidized bed lower section (4) are also connected by a flow guide pipe (3) for guiding the adsorbent particles in the fluidized bed middle section (2) into the fluidized bed lower section (4).

3. The fluidized bed of claim 1, wherein, The horizontal dimension of the fluidized bed lower section (4) is 50% of the horizontal dimension of the top of the fluidized bed upper section (1); The horizontal dimension of the fluidized bed middle section (2) is 90% of the horizontal dimension of the fluidized bed lower section (4).

4. An adsorption device, characterized by From top to bottom, it comprises, in sequence, a regenerator, a cooler, the fluidized bed of any one of claims 1-3, a preheater and a conveying bin; The cooler and the preheater are connected to circulate the gas in the cooler and the preheater; The bottom of the conveying bin is also connected to the regenerator.

5. The adsorption apparatus of claim 4, wherein It further comprises: A cyclone separator (10) connected to the fluidized bed; the inlet of the cyclone separator (10) is connected to the outlet of the fluidized bed upper section (1); the bottom outlet of the cyclone separator (10) is connected to the fluidized bed middle section (2); A bag-type dust collector (17) connected to the cyclone separator (10); A flue gas distribution cylinder (19) connected to the bag-type dust collector (17); A fan A (16) connected to the flue gas distribution cylinder (19); The flue gas distribution cylinder (19) is also connected to the bottom of the cooler through a fan B (18); The fan A (16) is connected to the top of the cooler; A dust collector (25) connected to the regenerator; A heat exchanger (24) connected to the dust collector (25); A condensation separation tank (23) connected to the heat exchanger (24); A gas distribution cylinder (22) connected to the condensation separation tank (23); The gas distribution cylinder (22) is also connected to the bottom of the regenerator and the top of the conveying bin through a compressor (21), respectively; A fan C (20) connected to the fluidized bed.

6. The adsorption apparatus of claim 5, wherein The preheater comprises a preheater A (6) and a preheater B (7); The conveying bin comprises a conveying bin A (8) and a conveying bin B (9); The cooler comprises a cooler A (11) and a cooler B (12); The regenerator comprises a regenerator A (13) and a regenerator B (14).

7. A method of capturing carbon dioxide, characterized by, In the adsorption device of claim 4, the following steps are performed: (1) passing flue gas containing carbon dioxide into the fluidized bed lower section (4) containing adsorbent particles, the fluidized bed middle section (2) containing adsorbent particles and the fluidized bed upper section (1) containing adsorbent particles to sequentially react with the adsorbent particles therein to carry out decarburization, obtaining fourth state flue gas in the fluidized bed upper section (1), and obtaining adsorbent particles containing adsorbed carbon dioxide in the fluidized bed lower section (4), the fluidized bed middle section (2) and the fluidized bed upper section (1); (2) The adsorbent particles that adsorb carbon dioxide obtained from the lower section (4) of the fluidized bed are sent to the preheater for preheating and then sent to the conveying bin and then to the regenerator for regeneration, and regenerated adsorbent particles are obtained; The regenerated adsorbent particles are sent to the cooler for cooling and then sent to the upper section (1) of the fluidized bed to repeat steps (1) and (2).

8. A method of capturing carbon dioxide, characterized by, In the adsorption equipment according to any one of claims 5-6, the following steps are included: (1) The flue gas containing carbon dioxide is pressurized by the fan C (20) and then enters the lower section (4) of the fluidized bed containing adsorbent particles through the gas distributor B (5) for adsorption, and second state flue gas and fourth state adsorbent particles are obtained; The second state flue gas is sent to the middle section (2) of the fluidized bed containing adsorbent particles for adsorption, and third state flue gas and third state adsorbent particles are obtained; The third state flue gas is sent to the upper section (1) of the fluidized bed containing adsorbent particles for adsorption, and fourth state flue gas and first state adsorbent particles are obtained; (2) The fourth state flue gas is sent to the cyclone separator (10) for separation, and separated adsorbent particles and separated flue gas are obtained; The separated adsorbent particles are returned to the reaction area of the middle section (2) of the fluidized bed for recycling, and the separated flue gas is sent to the bag filter (17) for dust removal, and clean flue gas is obtained; Part of the clean flue gas is sent to the flue gas distribution cylinder (19) to obtain part of the redistributed flue gas, which is pressurized by the fan A (16) and then circulated in the cooler and the preheater; The fourth state adsorbent particles are guided to the preheater and preheated by the hot flue gas obtained from the heat exchange process in the cooler, and then the obtained preheated fourth state adsorbent particles are sent to the conveying bin and then to the regenerator, and desorption reaction is carried out under the action of superheated steam, and regenerated adsorbent particles and mixed gas containing water vapor and carbon dioxide are obtained; (3) The mixed gas is sent to the dust remover C (25) for dust removal, and then the obtained clean mixed gas is sent to the heat exchanger (24) for heat exchange, and heat exchanged mixed gas is obtained; The heat exchanged mixed gas is sent to the condensing separation tank (23) for condensation, and condensed water and carbon dioxide are obtained; The carbon dioxide is sent to the gas distribution cylinder (22), and then part of the carbon dioxide is pressurized by the compressor (21) and used as the fluidizing gas for the regenerator and the conveying gas for the conveying bin, and the remaining carbon dioxide is sent to the gas storage tank as a product; (4) The regenerated adsorbent particles are sent to the cooler, and then mixed with part of the redistributed flue gas that is preheated by the fan A (16) and then sent to the cooler, and part of the clean flue gas that is sent to the cooler by the fan B (18), and then the obtained flue gas that is heated is sent to the preheater to exchange heat with the fourth state adsorbent particles, and then the flue gas that is cooled is returned to the cooler to absorb heat, until the fourth state adsorbent particles are cooled to the target value, and then the flue gas that is cooled and the flue gas that is circulated in the cooler and the heat exchanger are sent to the flue gas distribution cylinder (19), and the regenerated adsorbent particles that are cooled are sent to the reaction area of the upper section (1) of the fluidized bed for recycling.

9. The method of claim 8, wherein, The flow rate of the flue gas after pressurization by the fan C (20) is 15000 Nm 3 / h; The temperature of the flue gas is 70 DEG C, and the pressure of the flue gas is 2 kPaG; The volume fraction of CO2 in the flue gas is 10-14%, the volume fraction of O2 is 5-11%, the volume fraction of H2O is 10-14%, the concentration of SO2 is 10 mg / Nm 3 , the concentration of NO X is 50 mg / Nm 3 , the concentration of dust is 5 mg / Nm 3 ; and the remaining gas of the flue gas is nitrogen.

10. The method of claim 8, wherein, The adsorbent comprises an active component and a carrier supporting the active component; the active component comprises potassium carbonate; The carrier comprises Al2O3, ZrO2, TiO2 or activated carbon; The pressure of the superheated steam is 1.6 MPa, and the temperature is 255 DEG C.

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