Method and system for synthesizing CO through conversion of CO2 promoted by electric field

Abstract

The invention discloses a method and a system for synthesizing CO through conversion of CO2 promoted by an electric field, a mixed gas of CO2 and H2 is used as a raw material gas, and a metal rod which is connected with a direct-current power supply and applies a direct-current electric field to a catalyst is arranged; the raw material gas is subjected to a catalytic reaction under the action of a catalyst and a direct-current electric field to generate CO and H2O. According to the method, the activity of the catalyst is improved by utilizing the electric field, so that the conversion rate of CO2 and the selectivity of CO in the RWGS reaction are improved; the electric field intensity can be changed by changing an input current value, so that the catalyst activity is regulated; not only is CO2 emission reduced, but also CO2 resource utilization for preparation of high-value chemicals is realized. A catalyst bed layer of the system is arranged between two electrode plates connected with a direct-current high-voltage power supply, the two electrode plates are connected through a metal rod, an electric field is applied to the catalyst bed layer, current flows on the catalyst bed layer, the activity of the catalyst bed layer in a reactor is promoted to be improved by utilizing the electric field, and CO2 can be effectively promoted to be converted into CO.

Description

Technical Field

[0001] The present invention relates to CO 2 Conversion and utilization, especially an electric field-promoted CO 2 A method and system for converting and synthesizing CO. Background Art

[0002] Reduce CO 2 Emissions are an important issue concerning the sustainable development of the earth. Therefore, people pay close attention to CO 2 Chemically captured CO 2 As a raw material for catalytic reactions, it is not only beneficial to carbon emission reduction, but also can produce high-value chemical products, and CO 2 Catalytic immobilization as a chemical product helps to build a carbon-neutral cycle that is not dependent on plants or the climate.

[0003] CO 2 The conversion and synthesis of CO (RWGS reaction) is thermodynamically feasible and economically viable. The CO produced can be further used to produce olefins, hydrocarbons, alcohols and other chemical products through the Fischer-Tropsch synthesis process, and can be used to produce H generated by electrolysis of renewable energy. 2 When combined, it can provide a green route for fuel production, but the RWGS reaction requires a high temperature, and the reaction temperature under conventional thermal catalytic reaction systems is generally higher than 400°C. Based on this, it is urgent to develop a CO that can reduce the reaction temperature. 2 The method of converting and synthesizing CO can reduce carbon emissions while achieving CO 2 resource utilization. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an electric field-promoted CO 2 The present invention also provides a method for converting and synthesizing CO 2 A system for converting and synthesizing CO.

[0005] In order to solve the above technical problems, the technical solution adopted by the method of the present invention includes the following steps: 2 and H 2 The mixed gas is the raw gas, and a metal rod is provided which is connected to a DC power supply and applies a DC electric field to the catalyst; the raw gas undergoes a catalytic reaction under the action of the catalyst and the DC electric field to generate CO and H 2 O.

[0006] Furthermore, the current value of the direct current is 3-10 mA.

[0007] Furthermore, the resistance value of the metal rod is 10000-20000Ω.

[0008] Furthermore, the active metal of the catalyst is Pt, Pd, Ni, Fe or Cu.

[0009] In order to solve the above technical problems, the technical solution adopted by the system of the present invention is: including a reactor; the reactor includes a reactor shell, a catalyst bed and a metal rod; one end of the reactor shell is provided with a raw gas inlet and the other end is provided with a reaction gas outlet; the catalyst bed is arranged in the reactor shell, the metal rod passes through the catalyst bed and both ends are connected to a DC power supply.

[0010] Furthermore, it also includes a 2# electrode plate and a 1# electrode plate; the 2# electrode plate and the 1# electrode plate are respectively arranged at both ends of the catalyst bed, and the two ends of the metal rod are respectively connected to the DC power supply through the 2# electrode plate and the 1# electrode plate.

[0011] Furthermore, an insulating medium is provided between the catalyst bed and the reactor shell.

[0012] Furthermore, it also includes a heating furnace, a cooler, a compressor and a CO purification device; the inlet of the heating furnace is connected to the raw gas pipeline, and the outlet is connected to the raw gas inlet of the reactor; the reaction gas outlet of the reactor is connected to the cooler, the compressor and the CO purification device in sequence.

[0013] The beneficial effect of adopting the above technical solution is that the method of the present invention utilizes the electric field to promote the improvement of catalyst activity, thereby increasing the CO 2 The present invention can change the electric field intensity by changing the input current value, thereby regulating the catalyst activity and effectively reducing the reaction temperature; the present invention uses the electric field to promote CO 2 The conversion and synthesis of CO is not only beneficial to reduce CO 2 emissions, and also achieved CO 2 Resource utilization to prepare high-value chemicals.

[0014] The catalyst bed of the system of the present invention is placed between two electrode plates connected to a DC high voltage power supply, the two electrode plates are connected by a metal rod, an electric field is applied to the catalyst bed, and electric charges flow on the catalyst bed to improve the catalytic activity. The raw gas reacts to generate CO and H after being activated by the catalyst bed promoted by the electric field. 2 O; The system of the present invention utilizes electric field to promote the activity of the catalyst bed in the reactor, which can effectively promote CO 2 Converted into CO. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0016] Figure 1It is a structural schematic diagram of the system of the present invention; Figure 2 It is a structural schematic diagram of the reactor of the present invention; Figure 3 yes Figure 2 Top view of the horizontal cross section of the catalyst bed and metal rods.

[0017] In the figure: reaction gas outlet 1, raw gas inlet 2, reactor shell 3, insulating medium 4, catalyst bed 5, 2# electrode plate 6, 1# electrode plate 7, metal rod 8, reactor 9, cooler 10, compressor 11, CO purification device 12, heating furnace 13, CO storage tank 14. DETAILED DESCRIPTION

[0018] The electric field promotes the CO 2 The method for converting and synthesizing CO comprises the following steps: 1) using CO 2 and H 2 The mixed gas is the raw gas, and the raw gas is CO 2 / H 2 The volume ratio is 1:1 to 1:2, and the raw gas is heated to the reaction temperature; 2) The catalyst passes through a metal rod connected to a DC power supply, the resistance of the metal rod is 10000-20000Ω, and the DC current flowing through the metal rod is 3-10mA; the raw gas flows through the catalyst, and under the action of the DC electric field of the metal rod, the heated raw gas undergoes a catalytic reaction under the action of the catalyst, and the reaction temperature is 200℃-250℃; the metal rod applies a DC electric field to the catalyst, so that the charge flows on the catalyst bed, thereby improving the catalytic activity of the catalyst and enhancing the catalytic effect. The carrier of the catalyst is La-ZrO 2 , the active metal is Pt, Pd, Ni, Fe or Cu; the reaction produces CO and H 2 O mixture.

[0019] The reaction equation is: Main reaction: CO 2 +H 2 →CO+H 2 O; Side reaction: CO 2 +4H 2 →CH 4 +2H 2 O,CO 2 +3H 2 →CH 4 +H 2 O.

[0020] 3) The mixed gas is cooled and CO is purified to obtain pure CO gas.

[0021] Figure 1, 2 As shown, the electric field promotes the CO 2 The system for converting and synthesizing CO comprises a reactor 9, a heating furnace 13, a cooler 10, a compressor 11 and a CO purification device 12; the inlet of the heating furnace 13 is connected to the raw gas pipeline, and the outlet is connected to the raw gas inlet 2 of the reactor 9. The reaction gas outlet 1 of the reactor 9 is connected to the inlet of the cooler 10, the outlet of the cooler 10 is connected to the inlet of the compressor 11, and the outlet of the compressor 11 is connected to the inlet of the CO purification device 12; the desorption gas outlet of the CO purification device 12 is connected to the inlet of the heating furnace 13, and the product gas outlet of the CO purification device 12 is connected to the CO storage tank 14. The CO purification device 12 adopts pressure swing adsorption technology, cryogenic technology or membrane separation technology.

[0022] Figure 1 , 2 As shown, the electric field promotes the CO 2 The system for converting and synthesizing CO, the reactor 9 comprises a reactor shell 3, a catalyst bed 5, a 2# electrode plate 6, a 1# electrode plate 7 and a metal rod 8. The reactor shell 3 is a cavity structure, one end of the reactor shell 3 is provided with a raw gas inlet 2, and the other end is provided with a reaction gas outlet 1; preferably, the raw gas inlet 2 is provided at the bottom of the reactor shell 3, and the reaction gas outlet 1 is provided at the top of the reactor shell 3. The catalyst bed 5 is arranged in the inner cavity of the reactor shell 3, and the 2# electrode plate 6 and the 1# electrode plate 7 are respectively arranged at both ends of the catalyst bed 5 along the flow direction of the raw gas, preferably the 1# electrode plate 7 is arranged at the lower end of the catalyst bed 5, and the 2# electrode plate 6 is arranged at the upper end of the catalyst bed 5. The catalyst bed 5 is cylindrically arranged up and down, and the catalyst is arranged on the catalyst bed 5; the metal rod 8 passes through the center of the cylinder of the catalyst bed 5, and may or may not contact the catalyst bed 5. The two ends of the metal rod 8 are respectively connected to the 2# electrode plate 6 and the 1# electrode plate 7. The 2# electrode plate 6 and the 1# electrode plate 7 are connected to a DC high-voltage power supply. The reactor shell 3 is a metal shell, and an insulating medium 4 is provided between the catalyst bed 5 and the reactor shell; the insulating medium can be made of glass, ceramic or silica gel. The electric field in the reactor 9 of this system is generated by a DC high-voltage power supply, and the external electric field is formed when the metal rod passes current. After the electric field is applied, the positive and negative charges move upward and downward on the catalyst bed, thereby improving the catalyst activity and achieving the effect of lowering the reaction temperature. An insulating medium is provided between the catalyst bed and the reactor shell, which can form a dielectric barrier (DBD) in the electric field, thereby strengthening the formation of free radicals or ions by the raw gas molecules and improving the electric field strength promoted by the electric field.

[0023] Figure 1 , 2 As shown, the electric field promoted CO 2The production steps of the system for converting and synthesizing CO are as follows: 1) CO 2 and H 2 The mixed gas is the raw gas, including external CO 2 and H 2 The mixed gas and the analytical gas of the CO purification device 12; the raw gas is heated to a reaction temperature of 200°C to 250°C by a heating furnace 13; 2) The heated raw gas enters the reactor 9. At a reaction temperature of 200°C to 250°C, the raw gas is activated into free radicals or ions in the catalyst bed 5 promoted by the electric field, and reacts to generate CO and H 2 O mixture; 3) The mixed gas is dehydrated by the cooler 10 and pressurized by the compressor 11 before entering the CO purification device 12. The purified CO enters the CO storage tank 14, and the analyzed gas is mixed with the external CO 2 and H 2 Mixed gas mixture. Example 1

[0024] Raw gas CO 2 :H 2 The volume ratio is 1:1, the total flow rate is 1000ml / min, the raw gas enters the reactor after being heated to 200℃ in the heating furnace, the input current value is 3mA, the metal rod resistance value is 20000Ω, and the catalyst is 1wt%Pt / La-ZrO 2 ,CO 2 The conversion rate was 43.8% and the CO selectivity was 99.2%. Example 2

[0025] The other steps are the same as in Example 1, except that the input current is 5 mA, CO 2 The conversion rate was 45.5% and the CO selectivity was 99.0%. Example 3

[0026] The other steps are the same as in Example 1, except that the input current value is 7 mA, CO 2 The conversion rate was 48.2% and the CO selectivity was 99.4%. Example 4

[0027] The other steps are the same as in Example 1, except that the input current value is 10 mA, CO 2 The conversion rate was 49.5% and the CO selectivity was 99.5%. Example 5

[0028] The other steps are the same as in Example 1, except that the catalyst is 1wt% Pd / La-ZrO 2 , CO 2The conversion rate was 31.6% and the CO selectivity was 98.5%. Example 6

[0029] The other steps are the same as in Example 1, except that the catalyst is 1wt% Ni / La-ZrO 2 , CO 2 The conversion rate was 29.4% and the CO selectivity was 96.8%. Example 7

[0030] The other steps are the same as in Example 1, except that the catalyst is 1wt% Fe / La-ZrO 2 , CO 2 The conversion rate was 28.5% and the CO selectivity was 95.8%. Example 8

[0031] The other steps are the same as in Example 1, except that the catalyst is 1wt% Cu / La-ZrO 2 , CO 2 The conversion rate was 28.4% and the CO selectivity was 95.5%. Example 9

[0032] The other steps are the same as in Example 1, except that the raw gas CO 2 :H 2 The volume ratio is 1:1.5, the temperature is 250℃, CO 2 The conversion rate reached 45.6% and the CO selectivity was 96.6%.

[0033] Embodiment 10: The other steps are the same as in Example 1, except that the raw gas CO 2 :H 2 The volume ratio is 1:2, the temperature is 220℃, CO 2 The conversion rate reached 46.5% and the CO selectivity was 99.5%.

[0034] Embodiment 11: The other steps are the same as in Example 1, except that the resistance of the metal rod is 10000Ω, CO 2 The conversion rate was 32.8% and the CO selectivity was 99.2%.

[0035] Embodiment 12: The other steps are the same as in Example 1, except that the resistance of the metal rod is 15000Ω, CO 2 The conversion rate was 38.8% and the CO selectivity was 99.1%.

[0036] Comparative Example: The other steps are the same as in Example 1, except that the input current is 0 mA, the temperature is 500°C, and the CO2 The conversion rate was 23.6% and the CO selectivity was 91.6%.

[0037] It can be seen from the above embodiments and comparative examples that the method and system effectively improve the CO 2 Conversion rate and CO selectivity, CO 2 The conversion rate can reach over 28% and the CO selectivity can reach over 96%.

Claims

1. A method for converting CO2 to CO by electric field promotion, characterized in that: The method comprises the following steps: using a mixture of CO2 and H2 as raw gas, and providing a metal rod connected to a DC power supply and applying a DC electric field to a catalyst; the raw gas undergoes a catalytic reaction under the action of the catalyst and the DC electric field to generate CO and H2O.

2. The method for synthesizing CO by converting CO2 to CO using an electric field according to claim 1, characterized in that: The current value of the direct current is 3-10 mA.

3. The method for synthesizing CO by converting CO2 to CO using an electric field according to claim 1, characterized in that: The resistance value of the metal rod is 10000-20000Ω.

4. The method for synthesizing CO by converting CO2 to CO by electric field promotion according to claim 1, 2 or 3, characterized in that: The active metal of the catalyst is Pt, Pd, Ni, Fe or Cu.

5. A system for converting CO2 to CO by electric field promotion, characterized in that: The invention comprises a reactor (9); the reactor (9) comprises a reactor shell (3), a catalyst bed (5) and a metal rod (8); a raw gas inlet (2) is provided at one end of the reactor shell (3) and a reaction gas outlet (1) is provided at the other end; the catalyst bed (5) is arranged in the reactor shell (3), and the metal rod (8) passes through the catalyst bed (5) and is connected to a DC power supply at both ends.

6. The system for converting CO2 to CO by electric field promotion according to claim 5, characterized in that: It also includes a 2# electrode plate (6) and a 1# electrode plate (7); the 2# electrode plate (6) and the 1# electrode plate (7) are respectively arranged at two ends of the catalyst bed (5); and the two ends of the metal rod (8) are respectively connected to a DC power supply through the 2# electrode plate (6) and the 1# electrode plate (7).

7. The system for converting CO2 to CO by electric field promotion according to claim 5, characterized in that: An insulating medium (4) is provided between the catalyst bed (5) and the reactor shell.

8. A system for converting CO2 to CO by electric field promotion according to claim 5, 6 or 7, characterized in that: It also comprises a heating furnace (13), a cooler (10), a compressor (11) and a CO purification device (12); the inlet of the heating furnace (13) is connected to the raw gas pipeline, and the outlet is connected to the raw gas inlet (2) of the reactor (9); the reaction gas outlet (1) of the reactor (9) is connected to the cooler (10), the compressor (11) and the CO purification device (12) in sequence.

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