Coal-fired flue gas CO2 capture and conversion utilization integrated system and method

Abstract

The invention discloses a coal-fired flue gas CO2 capture and conversion utilization integrated system and method.The system comprises a first reactor and a second reactor which are arranged in parallel, and the first reactor and the second reactor are both filled with capture catalytic materials; the first reactor and the second reactor are both connected with an H2 storage tank, an N2 storage tank, a CH4 storage tank and a flue gas conveying pipeline, and the first reactor and the second reactor alternately carry out CO2 capture and CO2 conversion and utilization processes; the reactor filled with the trapping catalytic material is adopted, so that integration of CO2 trapping and conversion utilization can be realized, and the problems of high energy consumption and system complexity in CO2 release, separation, storage and conversion processes when CO2 trapping and conversion are carried out in two steps are solved; two reactors are arranged to alternately carry out CO2 capture and CO2 conversion and utilization processes, so that the continuous operation of the whole system is realized; and meanwhile, the system can realize the conversion and utilization of two kinds of CO2, namely methanation and dry reforming, so that the practicability of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-fired flue gas treatment, and in particular to a method for treating coal-fired flue gas CO 2 Integrated system and method for capture, conversion and utilization. Background Art

[0002] With the progress of industrialization, a large amount of fossil fuels have been consumed, resulting in an increase in the concentration of carbon dioxide in the atmosphere and an increasing global warming. Therefore, the capture of flue gas carbon dioxide has become an important strategic means to address climate change and the greenhouse effect. At the same time, the recovered carbon dioxide can generate important carbon-containing products through different chemical or biological pathways, which has important economic and environmental benefits. The absolute amount of carbon dioxide gas emissions from flue gas of coal-fired power plants accounts for about half of the total carbon dioxide gas emissions, and is the main source of greenhouse gas emissions. Therefore, the reduction and conversion of carbon dioxide gas from flue gas of coal-fired power plants will be one of the bottlenecks for the future sustainable development of coal-fired power generation, and it will be urgent.

[0003] In the prior art, for the capture of carbon dioxide, the chemical absorption method using alcohol amines as absorbents is relatively mature, but a large amount of steam heat is required in the regeneration process of the absorbent, resulting in a low efficiency of the steam power cycle, reducing the output power of the coal-fired unit, and causing the operation cost of the chemical absorption method for capturing carbon dioxide in flue gas to be expensive. In addition, alcohol amine absorbents are easily decomposed at high temperatures, so there are strict requirements on the pressure and temperature of carbon capture steam, which will cause the problem of mismatching of the steam extraction energy level, resulting in a waste of energy. In addition, the current capture system can only realize the capture of carbon dioxide, and the captured carbon dioxide needs to be stored and transported before conversion and utilization, and it is impossible to realize the integration of the capture and conversion of carbon dioxide, which undoubtedly increases the operating cost of carbon dioxide capture and conversion. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a coal-fired flue gas CO 2 Integrated capture and conversion utilization system and method can achieve CO 2 The integration of capture and conversion solves the problem of CO 2 CO capture and conversion in two steps 2 Problems of high energy consumption and complex systems in the release, separation, storage and conversion processes.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, there is provided a coal-fired flue gas CO 2The integrated capture and conversion utilization system comprises a first reactor and a second reactor arranged in parallel, wherein the first reactor and the second reactor are both filled with capture catalytic materials, and the first reactor and the second reactor are both connected with H 2 Storage tank, N 2 Storage tank, CH 4 The storage tank is connected to the flue gas transmission pipeline, and the first reactor and the second reactor are alternately CO 2 Capture and CO 2 Transformation and utilization process.

[0007] In some embodiments of the present invention, the first reactor and the second reactor are both connected to a heat exchanger, and high-temperature flue gas is introduced into the heat exchanger.

[0008] In some embodiments of the present invention, the capture catalytic material includes a carrier, a CO 2 The components of the adsorption sites and the metal elements of the catalytic active sites.

[0009] In some embodiments of the present invention, the carrier is made of a porous material CeO 2 、TiO 2 、Al 2 O 3 、SiO 2 and ZrO 2 One or more of the CO 2 The adsorption site composition is Na 2 O, MgO, Li 2 O, CaO, SrO and BaO, and the metal elements of the catalytic active sites are one or more of Pt, Pb, Rh, Ru, Ni, Fe and Co.

[0010] In some embodiments of the invention, CO 2 The reactor and flue gas pipeline of the capture process and N 2 The storage tanks are connected to conduct CO 2 The reactor and H 2 The storage tanks are connected to perform methanogenesis; the CO 2 Capture process and CO 2 The temperature of the conversion and utilization process is controlled at 300-350°C.

[0011] In some embodiments of the present invention, the capture catalytic material is MgO adsorbent and Ru / CeO 2 -Al 2 O 3 A physical mixture of catalysts, the preparation method of which is:

[0012] 4MgCO 3Mg(OH) 2 ·5H 2 O、LiNO 3 、NaNO 3 and KNO 3 Add deionized water, stir the obtained white slurry, and then dry and calcine to obtain MgO powder;

[0013] Will Ce(NO 3 ) 3 ·5H 2 O and Al(NO 3 ) 3 9H 2 O deionized water, first add P123 and stir to dissolve at room temperature, then add concentrated nitric acid and citric acid in turn, stir ultrasonically to form a sol, seal and place for a period of time, then roast, cool and screen to obtain CeO 2 -Al 2 O 3 Carrier;

[0014] CeO 2 -Al 2 O 3 Support added RuCl 3 The solution was stirred to evaporate the water, then dried and calcined, and finally heated in H 2 / N 2 Ru / CeO was obtained by reduction under atmosphere 2 -Al 2 O 3 catalyst;

[0015] MgO powder and Ru / CeO 2 -Al 2 O 3 The catalysts are mechanically blended to obtain captured catalytic materials.

[0016] In some embodiments of the present invention, the CO 2 The reactor and flue gas pipeline of the capture process and N 2 The storage tanks are connected to conduct CO 2 Reactors and CH conversion processes 4 The storage tanks are connected to perform dry reforming; the CO 2 Capture process and CO 2 The temperature of the conversion and utilization process is controlled at 600-900℃.

[0017] In some embodiments of the present invention, the capture catalytic material is a Ni / CaAl bifunctional material, and the preparation method of the Ni / CaAl bifunctional material is as follows:

[0018] Nickel, calcium, and aluminum acetate precursors and citric acid were dissolved in deionized water;

[0019] The mixture was stirred magnetically in a constant temperature water bath until a colloidal mixture was formed;

[0020] The wet gel is then dried and calcined to obtain the Ni / CaAl bifunctional material.

[0021] In a second aspect of the present invention, there is provided a coal-fired flue gas CO 2 Working methods of integrated capture and conversion system, including:

[0022] H was introduced into the reactor 2 and N 2 Perform pre-processing;

[0023] The reactor was fed with CO 2 、N 2 , O 2 and H 2 O clean flue gas, and the CO in the flue gas is captured by the catalytic material. 2 Adsorption of CO 2 Capture process;

[0024] After the material is saturated, stop introducing flue gas; then introduce N 2 Carry out purging;

[0025] After the purge was completed, H 2 and N 2 , the adsorbed CO 2 Methanation to complete CO 2 transformation and utilization process;

[0026] The first reactor performs CO 2 During the capture process, the second reactor performs CO 2 In the conversion and utilization process, the first reactor performs CO 2 During the conversion and utilization process, the second reactor performs CO 2 Capture process.

[0027] In a third aspect of the present invention, there is provided a coal-fired flue gas CO 2 Working methods of integrated capture and conversion system, including:

[0028] H was introduced into the reactor 2 and N 2 Perform pre-processing;

[0029] The reactor was fed with CO 2 、N 2 , O 2 and H2 O clean flue gas, and the CO in the flue gas is captured by the catalytic material. 2 Adsorption of CO 2 Capture process;

[0030] After the material is saturated, stop introducing flue gas; then introduce N 2 Carry out purging;

[0031] After the purge was completed, CH 4 , the adsorbed CO 2 With CH 4 Dry reforming to complete CO 2 transformation and utilization process;

[0032] The first reactor performs CO 2 During the capture process, the second reactor performs CO 2 In the conversion and utilization process, the first reactor performs CO 2 During the conversion and utilization process, the second reactor performs CO 2 Capture process.

[0033] One or more technical solutions of the present invention have the following beneficial effects:

[0034] (1) The coal-fired flue gas CO provided by the present invention 2 The integrated capture and conversion system uses a reactor filled with capture catalytic materials to achieve CO 2 The integration of capture and conversion solves the problem of CO 2 CO capture and conversion in two steps 2 The release, separation, storage and conversion process has high energy consumption and complex systems. The two reactors are set up to alternately carry out CO 2 Capture and CO 2 The conversion and utilization process realizes the continuous operation of the entire system; at the same time, the system can realize methanation or dry reforming of two CO 2 Transform and utilize to improve the practicality of the system.

[0035] (2) The connection structure of the system provided in the present invention is a combination of multiple process units, which can satisfy the needs of single CO 2 Adsorption or CO 2 Methanation or CH 4 -CO 2 The dry reforming process can also meet the adsorption-catalysis process. Through program control, it can achieve high automation and reduce the interference of human factors.

[0036] (3) The capture catalytic dual-function material used in the present invention allows the use of a single material and reactor to carry out CO at a single temperature.2 The capture and conversion of 2 Capturing CO from flue gas 2 The technical path of catalytically converting it into fuel is to 2 The capture and utilization of Mg and Ca provide an economical and efficient process route. Dual-functional materials can also select inorganic solid wastes such as fly ash and carbide slag with high Mg and Ca content as raw materials, and realize the resource utilization of inorganic solid wastes through efficient modification and modification of metal elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The coal-fired flue gas CO 2 Schematic diagram of integrated capture and conversion system Figure 1 ;

[0038] Figure 2 Schematic diagram of the integrated system for capturing and converting CO2 from coal-fired flue gas of the present invention Figure 2 ;

[0039] Figure 3 It is a schematic diagram of the connection between the reactor and the heat exchanger of the present invention;

[0040] Figure 4 MgO+5%Ru / 5%CeO of the present invention 2 -Al 2 O 3 Catalytic material for capturing CO 2 Capture amount and CH 4 Yield;

[0041] Figure 5 This is a flow chart of the working method of embodiment 2 of the present invention;

[0042] Figure 6 This is a flow chart of the working method of Example 3 of the present invention. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0044] Example 1

[0045] In a typical embodiment of the present invention, a coal-fired flue gas CO is proposed. 2 Integrated capture and conversion system, such as Figure 1 and Figure 2 As shown, the invention comprises a first reactor and a second reactor arranged in parallel, wherein the first reactor and the second reactor are both filled with a capture catalytic material, and the first reactor and the second reactor are both filled with H 2 Storage tank, N 2 Storage tank, CH 4The storage tank is connected to the flue gas transmission pipeline, and the first reactor and the second reactor are alternately CO 2 Capture and CO 2 Transformation and utilization process.

[0046] The structures and connecting pipelines of the first reactor and the second reactor in this embodiment are exactly the same. During the entire working process of the integrated system, the first reactor and the second reactor are set to run in parallel to achieve continuous operation of the entire system and improve working efficiency.

[0047] like Figure 3 As shown, the first reactor and the second reactor are both connected to a heat exchanger, and high-temperature flue gas is introduced into the heat exchanger to provide a high-temperature environment for the first reactor and the second reactor. The heat exchange tubes of the heat exchanger are provided with fins, and the heat exchange tube walls and fins can be in full contact with the dual-functional material. By adjusting the operating parameters of the external heat exchanger E1 and the heat exchanger E2, the internal temperature of the entire reactor can be effectively adjusted and maintained to ensure smooth reaction.

[0048] In this embodiment, the capture catalytic material is a CO 2 Capture and CO 2 Bifunctional materials for catalytic conversion, bifunctional materials must have CO 2 The capture catalytic material includes a carrier, a CO 2 The components of the adsorption sites and the metal elements of the catalytic active sites.

[0049] Specifically, the carrier is made of porous material CeO 2 、TiO 2 、Al 2 O 3 、SiO 2 and ZrO 2 One or more of them are prepared together to form a carrier material, the CO 2 The adsorption site composition is Na 2 O (medium temperature 300-350℃), MgO (medium temperature 300-350℃), Li 2 O (high temperature 600-900°C), CaO (high temperature 600-900°C), SrO and BaO in the same temperature range, and one or more of the metal elements Pt, Pb, Rh, Ru, Ni, Fe and Co in the catalytic active site.

[0050] The above CO 2The adsorption component and the porous carrier material can be prepared as a carrier of a new dual-functional material by mechanical blending in different proportions, precursor doping synthesis, etc. The active metal component can be composed of one or two or more of the above active metals in different proportions.

[0051] In this embodiment, the first reactor and the second reactor are connected with H 2 Storage tank, N 2 Storage tank, CH 4 Valves are provided on the pipes connected to the storage tank and the flue gas delivery pipe to enable different gases to be introduced into the reactor to perform different working processes.

[0052] In a specific implementation of this embodiment, CO 2 The reactor and flue gas pipeline of the capture process and N 2 The storage tanks are connected to conduct CO 2 The reactor and H 2 The storage tanks are connected to perform methanogenesis; the CO 2 Capture process and CO 2 The temperature of the conversion and utilization process is controlled at 300-350°C.

[0053] Its working principle is as follows Figure 1 and Figure 5 As shown, clean coal-fired flue gas (content 8-15V / V% CO 2 ) is introduced into the carbonization reactor, and the dual-functional material selectively adsorbs CO 2 Until saturation, discharge without CO 2 clean flue gas; then purged with nitrogen, the O 2 The content is reduced to the set content, 10-20v / v%H 2 / N 2 (a mixture of hydrogen and nitrogen with a hydrogen volume percentage of 10-20%) is introduced into the same reactor to absorb the CO 2 Methanation, since pure hydrogen is not easy to store and transport, N needs to be added 2 dilution, and in CO 2 The reduction reaction does not require high-purity hydrogen. Depending on the catalyst material, the CO content in the flue gas must be 2 Molar concentration and H 2 There is an optimal molar concentration ratio for the product (CH 4 +2H 2 O) is dried and compressed to obtain CH 4Products. Two reactors will be run in parallel throughout the process to achieve continuous operation. Both steps are carried out at one temperature (300-350°C), eliminating the "dead time" of heating or cooling the reactor, and the material will be captured and methanated alternately. The heat required for the reaction process can be provided by medium-temperature flue gas or medium-temperature steam.

[0054] The chemical formula for methanation is:

[0055] CO 2 +4H 2 →CH 4 +2H 2 OΔH=-165kJ / mol

[0056] Furthermore, the capture catalytic material is MgO adsorbent and Ru / CeO 2 -Al 2 O 3 A physical mixture of catalysts, the preparation method of which is:

[0057] 4MgCO 3 Mg(OH) 2 ·5H 2 O、LiNO 3 、NaNO 3 and KNO 3 Add deionized water, stir the obtained white slurry, and then dry and calcine to obtain MgO powder;

[0058] Will Ce(NO 3 ) 3 ·5H 2 O and Al(NO 3 ) 3 9H 2 O deionized water, first add P123 and stir to dissolve at room temperature, then add concentrated nitric acid and citric acid in turn, stir ultrasonically to form a sol, seal and place for a period of time, then roast, cool and screen to obtain CeO 2 -Al 2 O 3 Carrier;

[0059] CeO 2 -Al 2 O 3 Support added RuCl 3 The solution was stirred to evaporate the water, then dried and calcined, and finally heated in H 2 / N 2 Ru / CeO was obtained by reduction under atmosphere 2 -Al 2 O 3 catalyst;

[0060] MgO powder and Ru / CeO 2 -Al 2 O 3 The catalysts are mechanically blended to obtain captured catalytic materials.

[0061] In a specific implementation of this embodiment, the capture catalytic material uses a cheap high-capacity MgO adsorbent and 5% Ru / 5% CeO 2 -Al 2 O 3 Physical mixture of catalysts with a mass ratio of 2:1.

[0062] Preparation process of high-capacity MgO: 9.713 g 4MgCO 3 Mg(OH) 2 ·5H 2 O and 0.207 gLiNO 3 , 0.153 g NaNO 3 and 0.526 g KNO 3 Add 40 ml of deionized water and stir for 60 min. The obtained white slurry is dried at 120 ° C overnight and then calcined at 450 ° C for 4 h to obtain MgO powder. The addition of molten alkali metal nitrates (Li, Na, K) can prevent the formation of rigid, CO 2-containing particles on the surface of MgO particles. 2 impermeable, monodentate carbonate layers and promote rapid carbonate ion generation, resulting in high CO 2 Absorption rate.

[0063] 5%Ru / 5%CeO 2 -Al 2 O 3 Catalyst preparation process: According to CeO 2 The mass of Al 2 O 3 Calculate the mass of hydrated nitrates of cerium and aluminum by weighing Ce(NO 3 ) 3 ·5H 2 O and Al(NO 3 ) 3 9H 2O required mass, and dissolved in 40mL of deionized water, first add 1g P123 (PEO-PPO-PEO, non-ionic surfactant) and stir to dissolve at room temperature, then add the drugs in turn, then add 4 drops of 6mol / L concentrated nitric acid, add citric acid (the molar number of citric acid is 1.5 times the molar number of metal ions), and treat under ultrasound with a power of 60W for 30min (when sound waves propagate in the liquid, high-frequency pressure changes will be formed, resulting in tiny bubbles in the liquid. These bubbles will release huge energy when they collapse, thereby promoting the fusion and dispersion between the catalyst precursor solutions), then stir at 60℃ until a sol is formed, then seal and place at room temperature for 3 days, and then roast at 500℃ in an air atmosphere for 4 hours, with a heating rate of 2℃ / min. After cooling to room temperature, grind and sieve to obtain a 40-60 mesh sample. 2.0g 5% CeO 2 -Al 2 O 3 The carrier was added to 20 mL of a predetermined amount of RuCl 3 The black slurry was stirred at room temperature for 24 h, and then the water was evaporated by rotary evaporation at 80 °C. After that, the obtained black powder was dried at 100 °C overnight, calcined at 300 °C for 2 h, and heated at 10 v / v% H 2 / N 2 The mixture was reduced at 300 °C for 2 h under a carbon atmosphere.

[0064] For the above MgO adsorbent and 5%Ru / 5%CeO 2 -Al 2 O 3 The performance test of the physical mixture of the catalyst was carried out using a stainless steel tube as a reactor with a length and inner diameter of 50 cm and 0.635 cm respectively. Typically, 450 mg of powdered MgO + 5% Ru / 5% CeO 2 -Al 2 O 3 Placed in the middle of the reactor, fixed at both ends with quartz wool. Carbonization reaction (carbon capture stage) at 300℃ with 15v / v% CO 2 / N 2 (50 ml / min) for 60 min. Then, pure N 2 The reactor was purged for 5 min. The second stage was to switch the feed gas to renewable H 2 (15v / v%H 2 / N 2 ), with a flow rate of 50 ml / min, and then the captured CO 2 Convert to CH 4 A total of 5 process cycles were performed.

[0065] Five cycles of coal-fired flue gas CO 2 The results of the integrated cycle test of capture and methanogenesis are shown in Table 1 and Figure 4 As shown in Table 1 and Figure 4 It can be seen that in the five CO 2 In the adsorption-methane catalytic cycle test, MgO+5%Ru / 5%CeO 2 -Al 2 O 3 Dual-functional materials show good CO 2 Adsorption and catalytic properties, CO 2 The average conversion rate of CH 4 The average yield reached 4.97mmol / g, and the catalytic performance gradually decreased with the increase of the number of cycles. The decline in catalytic performance was mainly caused by carbon deposition blocking the pore structure of the bifunctional material or covering the active sites.

[0066] Combined sorbent and catalyst (dispersed MgO and Ru) for CO capture in the same reactor operating at the same temperature 2 , and by adding green H 2 Synthetic natural gas can then be recycled into industrial facilities, saving fuel while minimizing CO2 emissions.

[0067] Table 1MgO+5%Ru / 5%CeO 2 -Al 2 O 3 Adsorption-catalytic performance parameters of dual-functional materials

[0068]

[0069] In another specific implementation of this embodiment, the CO 2 The reactor and flue gas pipeline of the capture process and N 2 The storage tanks are connected to conduct CO 2 Reactors and CH conversion processes 4 The storage tanks are connected to perform dry reforming; the CO 2 Capture process and CO 2 The temperature of the conversion and utilization process is controlled at 600-900°C. Specifically, before the dry reforming reaction, the oxide active components of the catalyst need to be reduced to a single substance state with hydrogen. After the reduction is completed, the reaction gas CH 4 Conduct CH 4 +CO 2 →2H 2 +2CO reaction. In the reforming process, it is necessary to introduce N 2Dilute, according to the different catalytic materials, need to meet the CO content in the flue gas 2 Molar concentration and CH 4 The molar concentration is close to the optimal molar ratio of 1:1, N 2 Its main function is to act as a diluent gas.

[0070] like Figure 2 and Figure 6 As shown, clean coal-fired flue gas (8-15v / v% CO 2 ) is introduced into the carbonization reactor, and the dual-functional material selectively adsorbs CO 2 Until saturation, discharge without CO 2 clean flue gas; then purged with nitrogen, the O 2 The content is reduced to the set content, 10-20v / v% CH 4 / N 2 (methane volume percentage of 10-20% methane nitrogen mixture) is introduced into the same reactor to absorb the CO 2 With CH 4 Dry reforming reaction occurs. The product is dried and compressed to obtain (2CO+2H 2 ) products, which in turn serve as feed gas for the Fischer-Tropsch reaction in the subsequent process. Two reactors will be run in parallel throughout the process to achieve continuous operation. Both steps are carried out at one temperature (600-900°C), eliminating the "dead time" of heating or cooling the reactor, and the material will be captured and reacted with dry reforming alternately. The heat required for the reaction process can be provided by the high-temperature flue gas.

[0071] CO 2 With CH 4 The chemical formula for the dry reforming reaction is:

[0072] CH 4 +CO 2 →2H 2 +2COΔH=+247kJ / mol

[0073] Furthermore, the capture catalytic material adopts Ni / CaAl bifunctional material, and the preparation method of the Ni / CaAl bifunctional material is:

[0074] Nickel, calcium, and aluminum acetate precursors and citric acid were dissolved in deionized water;

[0075] The mixture was stirred magnetically in a constant temperature water bath until a colloidal mixture was formed;

[0076] The wet gel is then dried and calcined to obtain the Ni / CaAl bifunctional material.

[0077] In a specific implementation of this embodiment, the preparation method of the Ni / CaAl dual-functional material is:

[0078] Nickel, calcium and aluminum acetate precursors and citric acid were dissolved in deionized water. The molar ratio of citric acid to metal was set to 1.5, and the molar ratio of deionized water to metal was set to 50. The mixture was magnetically stirred in a constant temperature water bath at 85°C until a colloidal mixture was formed. The wet gel was then dried at 110°C overnight and then calcined at 850°C for 4 hours to obtain a 10% Ni / CaAl dual-functional material.

[0079] The pore structure parameters of the 10% Ni / CaAl bifunctional material are shown in Table 2, and the adsorption catalytic performance parameters are shown in Table 3. It can be seen from Table 2 and Table 3 that the 10% Ni / CaAl bifunctional material has good CO 2 Adsorption and catalytic conversion performance, CO after five adsorption-catalytic cycles 2 The adsorption capacity of CH 4 and CO 2 The average conversion rates of H 2 The ratio of / CO also reached 1.03. It can be seen that the use of cheap and readily available calcium-based bifunctional materials can maintain high CO 2 Capture capacity and CH 4 -CO 2 The catalytic performance remains good after multiple cycles.

[0080] Table 2 Pore structure parameters of bifunctional catalytic materials

[0081]

[0082] Table 3 Adsorption catalytic performance parameters of 10Ni / CaAl dual-functional materials

[0083]

[0084] In summary, the coal-fired flue gas CO provided in this embodiment 2 The integrated capture and conversion utilization system can realize both the methanation conversion and utilization of carbon dioxide and the dry reforming conversion and utilization of carbon dioxide and methane.

[0085] Example 2

[0086] In a typical implementation of this embodiment, a coal-fired flue gas CO is provided. 2 Working methods of integrated capture and conversion systems, such as Figure 5 As shown, including:

[0087] H was introduced into the reactor2 and N 2 Perform pre-processing;

[0088] The reactor was fed with CO 2 、N 2 , O 2 and H 2 O clean flue gas, and the CO in the flue gas is captured by the catalytic material. 2 Adsorption of CO 2 Capture process;

[0089] After the material is saturated, stop introducing flue gas; then introduce N 2 Carry out purging;

[0090] After the purge was completed, H 2 and N 2 , the adsorbed CO 2 Methanation to complete CO 2 transformation and utilization process;

[0091] The first reactor performs CO 2 During the capture process, the second reactor performs CO 2 In the conversion and utilization process, the first reactor performs CO 2 During the conversion and utilization process, the second reactor performs CO 2 Capture process.

[0092] In one embodiment, the pretreatment time is 30-180 min, and 10-20 v / v% H 2 / N 2 , airspeed 2000-6000h -1 ;CO 2 The adsorption time is 30-180 minutes, and the coal-fired flue gas introduced contains 8-15v / v% CO 2 , the space velocity (space velocity refers to the amount of raw material passing through a unit catalyst per unit time, and the space velocity here refers to the volume space velocity) is 1000-8000h -1 ; Nitrogen purge time is 2-10min, air velocity is 2000-6000h -1 , methanation time is 30-180min, 10-20v / v%H 2 / N 2 , airspeed 1000-8000h -1 The whole process is carried out at a temperature of 300-350°C.

[0093] Example 3

[0094] In a typical embodiment of the present invention, a coal-fired flue gas CO is provided.2 Working methods of integrated capture and conversion systems, such as Figure 6 As shown, including:

[0095] H was introduced into the reactor 2 and N 2 Perform pre-processing;

[0096] The reactor was fed with CO 2 、N 2 , O 2 and H 2 O clean flue gas, and the CO in the flue gas is captured by the catalytic material. 2 Adsorption of CO 2 Capture process;

[0097] After the material is saturated, stop introducing flue gas; then introduce N 2 Carry out purging;

[0098] After the purge was completed, CH 4 , the adsorbed CO 2 With CH 4 Dry reforming to complete CO 2 transformation and utilization process;

[0099] The first reactor performs CO 2 During the capture process, the second reactor performs CO 2 In the conversion and utilization process, the first reactor performs CO 2 During the conversion and utilization process, the second reactor performs CO 2 Capture process.

[0100] In one embodiment, the pretreatment time is 30-180 min, and 10-20 v / v% H 2 / N 2 , airspeed 2000-6000h -1 ;CO 2 The adsorption time is 30-180 minutes, and the coal-fired flue gas introduced contains 8%-15% CO 2 , airspeed 1000-8000h -1 ; Nitrogen purge time is 2-10min, air velocity is 2000-6000h -1 , CH 4 -CO 2 Dry reforming time is 30-180min, 10-20v / v%CH 4 / N 2 , airspeed 1000-8000h -1 The whole process is carried out at a temperature of 600-900°C.

[0101] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. An integrated system for capturing and converting CO2 from coal-fired flue gas, characterized in that: It comprises a first reactor and a second reactor arranged in parallel, wherein the first reactor and the second reactor are both filled with capture catalytic materials, and the first reactor and the second reactor are both connected to an H2 storage tank, an N2 storage tank, a CH4 storage tank and a flue gas conveying pipeline, and the first reactor and the second reactor alternately perform CO2 capture and CO2 conversion and utilization processes.

2. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 1, characterized in that: The first reactor and the second reactor are both connected to a heat exchanger, and high-temperature flue gas is introduced into the heat exchanger.

3. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 1, characterized in that: The capture catalytic material includes a carrier, a component of a CO2 adsorption site and a metal element of a catalytic active site.

4. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 3 is characterized in that: The carrier is made of one or more porous materials including CeO2, TiO2, Al2O3, SiO2 and ZrO2, the component of the CO2 adsorption site is made of one or more components including Na2O, MgO, Li2O, CaO, SrO and BaO, and the metal element of the catalytic active site is made of one or more components including Pt, Pb, Rh, Ru, Ni, Fe and Co.

5. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 1, characterized in that: The reactor for the CO2 capture process is connected to the flue gas pipeline and the N2 storage tank, and the reactor for the CO2 conversion and utilization process is connected to the H2 storage tank for methanation; the temperature of the CO2 capture process and the CO2 conversion and utilization process is controlled at 300-350°C.

6. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 5, characterized in that: The capture catalytic material is a physical mixture of MgO adsorbent and Ru / CeO2-Al2O3 catalyst, and its preparation method is as follows: 4MgCO3·Mg(OH)2·5H2O, LiNO3, NaNO3 and KNO3 were added into deionized water, the obtained white slurry was stirred, and then dried and calcined to obtain MgO powder; Ce(NO3)3·5H2O and Al(NO3)3·9H2O in deionized water are first added with P123 and stirred to dissolve at room temperature, and then concentrated nitric acid and citric acid are added in sequence, and ultrasonic stirring is performed to form a sol state, which is sealed and placed for a period of time, and then roasted, cooled and sieved to obtain a CeO2-Al2O3 carrier; The CeO2-Al2O3 carrier is added to the RuCl3 solution, and the water is evaporated after stirring, and then dried and calcined, and finally reduced in a H2 / N2 atmosphere to obtain a Ru / CeO2-Al2O3 catalyst; The capture catalytic material is obtained by mechanically mixing MgO powder and Ru / CeO2-Al2O3 catalyst.

7. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 1, characterized in that: The reactor for the CO2 capture process is connected to the flue gas pipeline and the N2 storage tank, and the reactor for the CO2 conversion and utilization process is connected to the CH4 storage tank for dry reforming; the temperature of the CO2 capture process and the CO2 conversion and utilization process is controlled at 600-900°C.

8. The integrated system for capturing and converting coal-fired flue gas CO2 as claimed in claim 7, characterized in that: The capture catalytic material adopts Ni / CaAl dual-functional material, and the preparation method of the Ni / CaAl dual-functional material is as follows: Nickel, calcium, and aluminum acetate precursors and citric acid were dissolved in deionized water; The mixture was stirred magnetically in a constant temperature water bath until a colloidal mixture was formed; The wet gel is then dried and calcined to obtain the Ni / CaAl bifunctional material.

9. A working method of the integrated system for capturing and converting coal-fired flue gas CO2 as claimed in any one of claims 1 to 8, characterized in that: include: H2 and N2 are introduced into the reactor for pretreatment; Clean flue gas containing CO2, N2, O2 and H2O is introduced into the reactor, and the CO2 in the flue gas is adsorbed by the capture catalytic material to carry out the CO2 capture process; After the material is saturated, stop introducing flue gas; then introduce N2 into the reactor for purging; After the purge is completed, H2 and N2 are introduced into the reactor to methanize the adsorbed CO2 and complete the CO2 conversion and utilization process; When the first reactor is performing a CO2 capture process, the second reactor is performing a CO2 conversion and utilization process; when the first reactor is performing a CO2 conversion and utilization process, the second reactor is performing a CO2 capture process.

10. A working method of the integrated system for capturing and converting CO2 from coal-fired flue gas as claimed in any one of claims 1 to 8, characterized in that: include: H2 and N2 are introduced into the reactor for pretreatment; Clean flue gas containing CO2, N2, O2 and H2O is introduced into the reactor, and the CO2 in the flue gas is adsorbed by the capture catalytic material to carry out the CO2 capture process; After the material is saturated, stop introducing flue gas; then introduce N2 into the reactor for purging; After the purge is completed, CH4 is introduced into the reactor to dry reform the adsorbed CO2 with CH4 to complete the CO2 conversion and utilization process; When the first reactor is performing a CO2 capture process, the second reactor is performing a CO2 conversion and utilization process; when the first reactor is performing a CO2 conversion and utilization process, the second reactor is performing a CO2 capture process.

Images