Method for preparing methanol through mild and efficient catalysis of CO2 hydrogenation under driving of electric field
By applying DC electricity to the catalyst bed in the hydrogenation of CO2 to methanol, changing the structure and electronic state of the catalyst, solving the problems of high energy consumption and low catalytic activity under high temperature and high pressure conditions, and achieving efficient CO2 conversion and methanol selection , demonstrates the advantages of electric field-driven catalysis with simplicity and low energy consumption.
Patent Information
- Application Number
- CN202411368403.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-01-03
AI Technical Summary
The existing CO2 hydrogenation and methanol production reactions need to be carried out under high temperature and high pressure conditions, resulting in high energy consumption, low catalytic activity and serious side reactions, resulting in increased production costs.
Using an electric field-driven thermoelectric coupling collaborative catalytic method, the high conversion of CO2 under milder conditions is achieved by applying DC electricity to the catalyst bed in a fixed bed reactor to change the structural properties and electronic state of the catalyst.
It has achieved the improvement of CO2 one-way conversion rate and excellent methanol selectivity, simple operation, short process, low energy consumption, good catalytic effect, and broad industrial application prospects.
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Figure CN119241332A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by an electric field, and belongs to the technical field of electrothermal coupling synergistic catalysis. Background Art
[0002] In the CO2 hydrogenation to methanol reaction, a thermal catalytic method is usually used, and a thermal catalytic method is also used in industrial CO hydrogenation to produce methanol units. However, CO2 has thermodynamic stability, which means that the CO2 hydrogenation to methanol reaction needs to be carried out under high temperature and high pressure conditions, which has high energy consumption and strict equipment requirements. In the CO2 hydrogenation to methanol reaction process, the reverse water-gas shift is the main side reaction, the main reaction is an exothermic reaction, and the reverse water-gas shift is an endothermic reaction. Therefore, high temperature conditions are not conducive to methanol production, but the CO2 conversion rate and methanol yield are both low under low temperature conditions. In view of this, the development of a new process for mild and efficient catalytic CO2 hydrogenation to methanol is an effective means to solve the problems of high energy consumption and low catalytic activity in the methanol production process.
[0003] Patents on the catalytic method of CO2 hydrogenation to methanol have been published. Chinese patent CN117865775A discloses a method for CO2 hydrogenation to methanol, which is to set a single-atom catalytic layer in a fixed bed reactor, connect the feed port of the fixed bed to CO2 and hydrogen sources, raise the temperature to 120-300°C, and the pressure to 5-6MPa, and use the contact between the raw material and the catalyst single-atom layer to improve the single-pass conversion rate of CO2. Chinese patent CN109999743A discloses an experimental device and method for photoelectric synergistic catalytic CO2 hydrogenation to methanol, which is electrically assisted on the basis of photocatalysis, so that the external voltage generated by the electric field promotes the electron migration of light, prevents the recombination of photogenerated electrons and holes, increases the number of electrons required for the reaction, and electrocatalysis promotes the directional transmission of photocharges. Photocatalysis makes up for the problems of excessive energy consumption in the electrocatalytic process, and the synergistic effect of the two improves the reaction rate. Chinese patent CN1580268A discloses a biocatalytic method for preparing methanol from CO2, which uses CO2 or a mixture of CO2 and air as reactants, and methane-oxidizing bacterial cells Methylocybin as catalysts. A shaking reactor is used to achieve the conversion of CO2 into methanol under mild conditions, solving the problems of high temperature, high pressure, strong corrosiveness, serious environmental pollution, and high energy consumption in the traditional CO2 to methanol process.
[0004] The catalytic methods for producing methanol from CO2 hydrogenation that have been implemented in the laboratory mainly include thermal catalysis, electrochemical catalysis, photoelectrocatalysis, photothermal catalysis, etc. All of the above methods require harsh reaction conditions to obtain a high CO2 conversion rate, resulting in high energy consumption in the reaction process, serious side reactions, low CO2 single-pass conversion rate, increased production costs, etc. In view of the current technical status, the present invention has developed a new, simple and feasible method for producing methanol from CO2. Summary of the invention
[0005] The present invention provides a method for producing methanol by mild and efficient catalytic hydrogenation of CO2 driven by electric field. On the one hand, the solid catalyst changes its structural properties and electronic state by applying direct current to the catalyst bed on the basis of traditional heating; on the other hand, CO2 molecules are activated by applying external current, so that a higher conversion rate can be achieved under relatively mild conditions. The method for producing methanol by mild and efficient catalytic hydrogenation of CO2 driven by electric field proposed by the present invention has the advantages of simple operation, short process, low energy consumption, and good catalytic activity.
[0006] The present invention can achieve the above-mentioned purpose through the following technical solutions:
[0007] A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field, characterized in that the catalytic method is thermoelectric coupling synergistic catalysis. The catalyst is loaded into a fixed bed reactor, and direct current is directly applied to the catalyst bed to achieve CO2 conversion to methanol at a certain temperature and pressure.
[0008] The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field is characterized in that the positive and negative electrodes of the DC power supply are in contact with the upper and lower beds of the catalyst respectively;
[0009] The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by an electric field is characterized in that the conductive metal rod of the DC power supply is in direct contact with the reaction atmosphere;
[0010] The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field is characterized in that the conductive metal rod and the fixed bed reaction tube are connected by polytetrafluoroethylene or other insulating materials;
[0011] The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field is characterized in that a quartz tube is filled at the contact point between the catalyst inside the reaction tube and the reaction tube for insulation;
[0012] The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field is characterized in that the power range of the DC power application is 0-2.5W;
[0013] The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by an electric field is characterized in that the temperature rise range of the catalyst bed caused by the DC power supply should be controlled to be 0-10°C;
[0014] Based on the technical requirements of the above-mentioned electric field driven mild and efficient catalytic CO2 hydrogenation method for producing methanol, the specific implementation steps are as follows:
[0015] (1) weighing a certain mass of CuZnAl catalyst, the catalyst mesh number is 20-40 mesh, and loading it into a fixed bed reaction tube so that the catalyst is evenly distributed in the reaction tube;
[0016] (2) Insert the conductive metal rods into the upper and lower catalyst beds respectively, ensuring that the positive and negative conductive metal rods of the DC power supply are inserted into the catalyst bed without contact and with a gap between them;
[0017] (3) At a temperature of 300°C, introduce 10% H2 / N2 reducing gas for 4 hours;
[0018] (4) After the reduction is completed, the reducing gas is switched to N2 and cooled to room temperature;
[0019] (5) After (4) is completed, switch N2 to the reaction atmosphere (H2 / CO2=3) and replace the pipeline for 0.5h;
[0020] (6) After (5) is completed, close all valves in the pipeline, adjust the pressure reducing valve to an appropriate position, and start pressurizing to 3.0 MPa;
[0021] (7) After (6) is completed, turn on the DC power supply, set the applied electric field power, observe the temperature rise of the equipment, and appropriately adjust and lower the heating temperature according to the temperature rise degree;
[0022] (8) After (7) is stabilized, start heating to 240°C and stabilize for 6 hours. After stabilization, take samples for analysis;
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] (1) A new method for mild and efficient catalytic hydrogenation of CO2 to methanol driven by electric field is proposed. Direct current is directly applied to the catalyst bed to improve the single-pass conversion rate and methanol selectivity of the reaction. The catalytic method is simple to operate, has a short process, low energy consumption, good catalytic effect, and the obtained CO2 single-pass conversion rate is high and the methanol selectivity is excellent.
[0025] (2) When a DC power supply is applied, the current acts on the catalyst bed, causing the catalyst structure to change, forming more Cu-ZnO sites that are beneficial to methanol synthesis, while improving the catalyst stability and promoting CO2 catalytic conversion;
[0026] (3) When a DC power supply is applied, the electronic state of the catalyst Cu changes. + / (Cu 0 +Cu + ) ratio is 0.7, which is closest to the Cu + / (Cu 0 +Cu +) ratio, effectively improving the selectivity of methanol;
[0027] (4) This catalytic method has high efficiency, good technical stability, low energy consumption, and broad industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 Schematic diagram of the experimental device for the catalytic method implemented in the present invention DETAILED DESCRIPTION
[0029] The present invention is further described in detail by specific embodiments, but should not be limited to the following embodiments. Without departing from the above technical concept of the present invention, various substitutions and changes made according to common technical knowledge and conventional means in the art should be included in the scope of the present invention.
[0030] Embodiment 1:
[0031] (1) Weigh 3.0 g of 57% Cu / ZnO / Al2O3 catalyst with a mesh size of 20-40 and load it into a fixed bed reaction tube. Use a rubber hammer to gently tap the wall of the reaction tube to ensure that the catalyst is evenly and tightly distributed in the reaction tube.
[0032] (2) 100 mL / min of reducing gas (10% H2 / N2) was introduced into the reaction tube, and the reactor temperature was raised to 300°C at a heating rate of 10°C / min and maintained for 4 h.
[0033] (3) After step (2) is completed, switch the reducing gas (10% H2 / N2, 100 mL / min) to N2 (50 mL / min) and wait for the temperature to drop to room temperature.
[0034] (4) After step (3) is completed, switch N2 (50 mL / min) to reaction gas (CO2 / N2 / H2=24 / 4 / 72, 100 mL / min), and replace the pipeline with the reaction gas for 0.5 h.
[0035] (5) After step (4) is completed, close all valves of the reactor, start to increase the pressure, and slowly adjust the outlet pressure reducing valve until the pressure rises to 3.0 MPa.
[0036] (6) After step (5) is stabilized, the catalyst bed temperature in the reaction tube is raised to 240°C at a heating rate of 10°C / min, and after stabilization for 6 hours, a sample is taken for analysis.
[0037] Embodiment 2:
[0038] (1) Weigh 3.0 g of 57% Cu / ZnO / Al2O3 catalyst with a mesh size of 20-40 and load it into a fixed bed reaction tube. Use a rubber hammer to gently tap the wall of the reaction tube to ensure that the catalyst is evenly and tightly distributed in the reaction tube.
[0039] (2) Insert the conductive metal rod into the catalyst bed, and ensure that the positive and negative metal rods of the DC power supply are inserted into the upper and lower catalyst beds respectively, and the metal rods do not touch each other.
[0040] (3) 100 mL / min of reducing gas (10% H2 / N2) was introduced into the reaction tube, and the reactor temperature was raised to 300°C at a heating rate of 10°C / min and maintained for 4 h.
[0041] (4) After step (3) is completed, switch the reducing gas (10% H2 / N2, 100 mL / min) to N2 (50 mL / min) and wait for the temperature to drop to room temperature.
[0042] (5) After step (4) is completed, switch N2 (50 mL / min) to reaction gas (CO2 / N2 / H2=24 / 4 / 72, 100 mL / min), and replace the pipeline with the reaction gas for 0.5 h.
[0043] (6) After step (5) is completed, close all valves of the reactor, start to increase the pressure, and slowly adjust the outlet pressure reducing valve until the pressure rises to 3.0 MPa.
[0044] (7) After step (6) is completed, turn on the DC power supply, set the current and voltage respectively, and ensure that the electric field power applied to the catalyst bed is 0.5W.
[0045] (8) After step (7) is stabilized, the catalyst bed temperature in the reaction tube is raised to 240°C at a heating rate of 10°C / min, and after stabilization for 6 hours, a sample is taken for analysis. Recorded as CZA-0.5W.
[0046] Embodiment 3:
[0047] (1) Weigh 3.0 g of 57% Cu / ZnO / Al2O3 catalyst with a mesh size of 20-40 and load it into a fixed bed reaction tube. Use a rubber hammer to gently tap the wall of the reaction tube to ensure that the catalyst is evenly and tightly distributed in the reaction tube.
[0048] (2) Insert the conductive metal rod into the catalyst bed, and ensure that the positive and negative metal rods of the DC power supply are inserted into the upper and lower catalyst beds respectively, and the metal rods do not touch each other.
[0049] (3) 100 mL / min of reducing gas (10% H2 / N2) was introduced into the reaction tube, and the reactor temperature was raised to 300°C at a heating rate of 10°C / min and maintained for 4 h.
[0050] (4) After step (3) is completed, switch the reducing gas (10% H2 / N2, 100 mL / min) to N2 (50 mL / min) and wait for the temperature to drop to room temperature.
[0051] (5) After step (4) is completed, switch N2 (50 mL / min) to reaction gas (CO2 / N2 / H2=24 / 4 / 72, 100 mL / min), and replace the pipeline with the reaction gas for 0.5 h.
[0052] (6) After step (5) is completed, close all valves of the reactor, start to increase the pressure, and slowly adjust the outlet pressure reducing valve until the pressure rises to 3.0 MPa.
[0053] (7) After step (6) is completed, turn on the DC power supply, set the current and voltage respectively, and ensure that the electric field power applied to the catalyst bed is 1.0 W.
[0054] (8) After step (7) is stabilized, the catalyst bed temperature in the reaction tube is raised to 240°C at a heating rate of 10°C / min, and after stabilization for 6 hours, a sample is taken for analysis. Recorded as CZA-1.0W.
[0055] Embodiment 4:
[0056] (1) Weigh 3.0 g of 57% Cu / ZnO / Al2O3 catalyst with a mesh size of 20-40 and load it into a fixed bed reaction tube. Use a rubber hammer to gently tap the wall of the reaction tube to ensure that the catalyst is evenly and tightly distributed in the reaction tube.
[0057] (2) Insert the conductive metal rod into the catalyst bed, and ensure that the positive and negative metal rods of the DC power supply are inserted into the upper and lower catalyst beds respectively, and the metal rods do not touch each other.
[0058] (3) 100 mL / min of reducing gas (10% H2 / N2) was introduced into the reaction tube, and the reactor temperature was raised to 300°C at a heating rate of 10°C / min and maintained for 4 h.
[0059] (4) After step (3) is completed, switch the reducing gas (10% H2 / N2, 100 mL / min) to N2 (50 mL / min) and wait for the temperature to drop to room temperature.
[0060] (5) After step (4) is completed, switch N2 (50 mL / min) to reaction gas (CO2 / N2 / H2=24 / 4 / 72, 100 mL / min), and replace the pipeline with the reaction gas for 0.5 h.
[0061] (6) After step (5) is completed, close all valves of the reactor, start to increase the pressure, and slowly adjust the outlet pressure reducing valve until the pressure rises to 3.0 MPa.
[0062] (7) After step (6) is completed, turn on the DC power supply, set the current and voltage respectively, and ensure that the electric field power applied to the catalyst bed is 1.5W.
[0063] (8) After step (7) is stabilized, the catalyst bed temperature in the reaction tube is raised to 240°C at a heating rate of 10°C / min, and after stabilization for 6 hours, a sample is taken for analysis. Recorded as CZA-1.5W.
[0064] Embodiment 5:
[0065] (1) Weigh 3.0 g of 57% Cu / ZnO / Al2O3 catalyst with a mesh size of 20-40 and load it into a fixed bed reaction tube. Use a rubber hammer to gently tap the wall of the reaction tube to ensure that the catalyst is evenly and tightly distributed in the reaction tube.
[0066] (2) Insert the conductive metal rod into the catalyst bed, and ensure that the positive and negative metal rods of the DC power supply are inserted into the upper and lower catalyst beds respectively, and the metal rods do not touch each other.
[0067] (3) 100 mL / min of reducing gas (10% H2 / N2) was introduced into the reaction tube, and the reactor temperature was raised to 300°C at a heating rate of 10°C / min and maintained for 4 h.
[0068] (4) After step (3) is completed, switch the reducing gas (10% H2 / N2, 100 mL / min) to N2 (50 mL / min) and wait for the temperature to drop to room temperature.
[0069] (5) After step (4) is completed, switch N2 (50 mL / min) to reaction gas (CO2 / N2 / H2=24 / 4 / 72, 100 mL / min), and replace the pipeline with the reaction gas for 0.5 h.
[0070] (6) After step (5) is completed, close all valves of the reactor, start to increase the pressure, and slowly adjust the outlet pressure reducing valve until the pressure rises to 3.0 MPa.
[0071] (7) After step (6) is completed, turn on the DC power supply, set the current and voltage respectively, and ensure that the electric field power applied to the catalyst bed is 2.0W.
[0072] (8) After step (7) is stabilized, the catalyst bed temperature in the reaction tube is raised to 240°C at a heating rate of 10°C / min, and after stabilization for 6 hours, a sample is taken for analysis. Recorded as CZA-2.0W.
[0073] Embodiment 6:
[0074] (1) Weigh 3.0 g of 57% Cu / ZnO / Al2O3 catalyst with a mesh size of 20-40 and load it into a fixed bed reaction tube. Use a rubber hammer to gently tap the wall of the reaction tube to ensure that the catalyst is evenly and tightly distributed in the reaction tube.
[0075] (2) Insert the conductive metal rod into the catalyst bed, and ensure that the positive and negative metal rods of the DC power supply are inserted into the upper and lower catalyst beds respectively, and the metal rods do not touch each other.
[0076] (3) 100 mL / min of reducing gas (10% H2 / N2) was introduced into the reaction tube, and the reactor temperature was raised to 300°C at a heating rate of 10°C / min and maintained for 4 h.
[0077] (4) After step (3) is completed, switch the reducing gas (10% H2 / N2, 100 mL / min) to N2 (50 mL / min) and wait for the temperature to drop to room temperature.
[0078] (5) After step (4) is completed, switch N2 (50 mL / min) to reaction gas (CO2 / N2 / H2=24 / 4 / 72, 100 mL / min), and replace the pipeline with the reaction gas for 0.5 h.
[0079] (6) After step (5) is completed, close all valves of the reactor, start to increase the pressure, and slowly adjust the outlet pressure reducing valve until the pressure rises to 3.0 MPa.
[0080] (7) After step (6) is completed, turn on the DC power supply, set the current and voltage respectively, and ensure that the electric field power applied to the catalyst bed is 2.5W.
[0081] (8) After step (7) is stabilized, the catalyst bed temperature in the reaction tube is raised to 240°C at a heating rate of 10°C / min, and after stabilization for 6 hours, a sample is taken for analysis. Recorded as CZA-2.5W
[0082] The above catalyst activity test experiments at different powers were carried out in an electrode fixed bed reactor with a catalyst loading of 3.0 g, raw material H2 / CO2=3 / 1, and a reaction space velocity of 2000 mL·g cat -1 ·h -1 , the reaction pressure is 3.0MPa, the reaction temperature is 240℃, and the activity evaluation results are shown in Table 1:
[0083] Table 1: Catalytic performance of catalysts obtained under different electric field powers
[0084]
[0085]
[0086] It can be seen from the activity evaluation results of the examples in Table 1 that the catalytic performance of the catalyst shows good catalytic activity by adopting the electrothermal catalysis method. Compared with the evaluation results of traditional thermal catalysis, electrothermal catalysis greatly improves the single-pass conversion rate of carbon dioxide and the selectivity of methanol. This is because the electric field directly acts on the catalyst bed, inducing the structural properties of the catalyst to change, thereby causing the catalyst to form more Cu-ZnO sites, and at the same time changing the electronic composition of the catalyst, so that it has the most suitable Cu for methanol generation. + / (Cu 0 +Cu + ) ratio. The use of the electrothermal catalytic method reduces the conditions required for the reaction and further improves the catalytic activity of the catalyst.
Claims
1. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field, characterized in that: The catalytic method is thermoelectric coupled synergistic catalysis, in which the catalyst is loaded into a fixed bed reactor, and direct current is directly applied to the catalyst bed to achieve CO2 conversion into methanol at a certain temperature and pressure.
2. The method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as claimed in claim 1, characterized in that A DC power supply is used to directly act on the catalyst bed, and the structural properties and electronic state of the catalyst are changed by DC induction. The specific operation steps are as follows: (1) weighing a certain mass of CuZnAl catalyst, the catalyst mesh number is 20-40 mesh, and loading it into a fixed bed reactor so that the catalyst is evenly distributed in the reaction tube; (2) Insert the conductive metal rods into the upper and lower catalyst beds respectively, ensuring that the positive and negative conductive metal rods of the DC power supply are inserted into the catalyst bed without contact and with a gap between them; (3) At a temperature of 300°C, introduce 10% H2 / N2 reducing gas for 4 hours; (4) After the reduction is completed, the reducing gas is switched to N2 and cooled to room temperature; (5) After (4) is completed, switch N2 to the reaction atmosphere (H2 / CO2=3) and replace the pipeline for 0.5h; (6) After (5) is completed, close all valves in the pipeline, adjust the pressure reducing valve to an appropriate position, and start pressurizing to 3.0 MPa; (7) After (6) is completed, turn on the DC power supply, set the applied electric field power, observe the temperature rise of the equipment, and appropriately adjust and lower the heating temperature according to the temperature rise degree; (8) After (7) is stabilized, start heating to 240°C and stabilize for 6 hours. After stabilization, take samples for analysis.
3. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as described in claims 1-2, characterized in that: The positive and negative electrodes of the DC power supply are in contact with the upper and lower beds of the catalyst respectively.
4. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as described in claims 1-3, characterized in that: The conductive metal rod of the DC power supply is in direct contact with the reaction atmosphere.
5. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as described in claims 1-4, characterized in that: The conductive metal rod and the fixed bed reaction tube are connected by polytetrafluoroethylene or other insulating materials.
6. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as described in claims 1-5, characterized in that: The contact point between the catalyst inside the reaction tube and the reaction tube is insulated by a quartz tube.
7. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as described in claims 1-6, characterized in that: The DC power applied ranges from 0 to 2.5W.
8. A method for producing methanol by mild and efficient catalytic CO2 hydrogenation driven by electric field as claimed in claims 1 to 7, characterized in that: The catalyst bed temperature rise range caused by the DC power supply should be controlled within 0-10°C.