Reaction device and method for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology

Abstract

This invention discloses a reaction device and method for converting carbon dioxide from flue gas based on ferroelectric photocatalysis. This device addresses the high cost of capturing and separating pure carbon dioxide from flue gas, as well as the low utilization rate of existing photocatalytic carbon dioxide reduction technologies. It proposes an in-situ conversion of carbon dioxide from flue gas into high-value-added energy products, achieving a carbon cycle. The device includes a flue gas flow control system, a humidity control system, a wind speed and frequency control system, a catalytic reaction system, and a product collection and analysis system. Based on photocatalytic conversion technology, the invention utilizes ferroelectric semiconductor materials and integrates them with flue gas from high-energy-consuming industries, effectively and cost-effectively converting carbon dioxide from flue gas into high-value-added fuels.

Description

Technical Field

[0001] The present invention belongs to the field of carbon neutrality technology, and specifically designs a reaction device and method for converting carbon dioxide in flue gas based on ferroelectric photocatalysis.

[0002] It is specifically applicable to the fields of environmental technology and carbon dioxide resource utilization. Background Art

[0003] With the continuous advancement of global industrialization, large amounts of carbon dioxide are released into the atmosphere, contributing to global warming and climate change. Approximately 65% ​​of global carbon dioxide emissions today come from flue gases from furnaces in energy-intensive, fossil fuel-based industries (such as power plants, cement plants, and steel mills). Therefore, developing technologies to capture and utilize carbon dioxide from furnace flue gases not only effectively alleviates environmental problems and fully utilizes carbon resources, but is also a strategic option for sustainable development. However, the complex composition of flue gas and the high costs of separating, purifying, and transporting the carbon dioxide hinder its reuse. Coupling the capture of carbon dioxide from flue gas with the conversion process to in-situ convert it into high-value-added chemical and energy products is an urgent challenge to achieve a carbon cycle. In recent years, researchers around the world have initiated research on "artificial photosynthesis" (i.e., photocatalysis), which uses catalysts to convert carbon dioxide into fuels or chemical feedstocks under the action of sunlight. Because photocatalysis uses clean solar energy to convert chemical energy, it balances energy, environmental, and economic requirements and is currently considered the most promising carbon dioxide conversion technology.

[0004] Ferroelectric semiconductor materials can be manipulated by applying external mechanical forces or temperature to control the magnitude of their built-in electric field, while also controlling the direction and magnitude of the polarization within the material, thereby adjusting the degree of local band bending at the interface of ferroelectric reactants, thereby achieving dynamic control of surface properties and catalytic redox reactions. Researchers have found that the band structures of many ferroelectric semiconductor materials match the reduction / oxidation potentials of carbon dioxide / water, and that their piezoelectric or spontaneous polarization effects can be coupled with the photocatalytic effect, promoting the rapid migration of electrons and holes, extending their lifetime, and improving the photocatalytic carbon dioxide conversion efficiency of ferroelectric semiconductor materials.

[0005] The current photocatalytic carbon dioxide reaction device is only suitable for the photocatalytic conversion of pure carbon dioxide at room temperature. If it is directly used for the conversion of high-humidity and high-temperature furnace exhaust gas, it will cause a series of problems such as catalyst instability, low carbon dioxide conversion efficiency, and high cost. Summary of the Invention

[0006] The purpose of the present invention is to provide a reaction device and method for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology. Ferroelectric semiconductor materials are used as catalysts, and carbon dioxide is converted efficiently and at low cost through organic integration with the thermal system of furnace flue gas, thereby improving the reduction efficiency of ferroelectric photocatalysts and realizing the maximum utilization of resources of low-concentration carbon dioxide and low-frequency airflow in flue gas.

[0007] To achieve the above-mentioned purpose, the device of the present invention includes a flue gas buffer bottle, a carbon dioxide concentration detector, and a carbon dioxide reactor that are connected in sequence. The inlet of the flue gas buffer bottle is connected to the incoming smoke pipe. A flow controller is installed on the pipe between the flue gas buffer bottle and the carbon dioxide concentration detector. A humidity controller and a flow controller are installed in sequence on the pipe between the carbon dioxide concentration detector and the carbon dioxide reactor. The carbon dioxide reactor includes a shell and a sample-carrying screen arranged in the shell for placing a ferroelectric photocatalyst. The sample-carrying screen separates the carbon dioxide reactor into a lower reaction chamber and an upper reaction chamber. The inlet of the lower reaction chamber is installed with turbine blades. The top of the upper reaction chamber is provided with a solar simulator. An outlet connected to a gas collector is provided on the side wall of the upper reaction chamber. A gas chromatograph is also installed on the outlet of the gas collector.

[0008] A check valve is installed between the humidity controller and the flow controller to allow the smoke to flow in one direction.

[0009] The top of the carbon dioxide reactor is sealed with a sealing sheet made of a transparent material.

[0010] The air inlet of the gas collection tank extends to the bottom of the gas collection tank, and the air outlet is arranged at the bottle mouth.

[0011] The ferroelectric photocatalyst is a ferroelectric photocatalyst that has been subjected to external electric field corona polarization.

[0012] The accuracy of the carbon dioxide concentration detector should reach ±0.5%.

[0013] The method for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology using the above device includes the following steps:

[0014] 1) Flue gas flow control system: Flue gas is charged into a flue gas buffer bottle, and the flow rate of the flue gas is controlled to 20-50 m / s by a flow controller. The carbon dioxide content in the flue gas is then detected by a carbon dioxide concentration detector to obtain the amount of ferroelectric photocatalyst used;

[0015] 2) Humidity control system: The flue gas enters the humidity controller at a uniform speed to adjust the relative humidity of the flue gas to 20% to 50%;

[0016] 3) Wind speed and frequency control system: After humidification, the flue gas enters the flow controller through the check valve, and the flow controller adjusts the flow rate of the humidified flue gas to 50-100m / s;

[0017] 4) Frequency control: The flue gas after the flow rate is adjusted by the flow controller is adjusted to 0~10 under the action of the turbine blades. 5 The Hz spiral airflow provides a continuous dynamic pressure on the surface of the ferroelectric photocatalyst;

[0018] 5) Catalytic Reaction System: A ferroelectric photocatalyst is spread flat on a sample-carrying sieve. The intensity of a solar simulator is adjusted to irradiate light vertically from above and below the surface of the ferroelectric photocatalyst. Under the action of light radiation and a spiral humidified flue gas flow, the ferroelectric photocatalytic carbon dioxide reduction reaction occurs.

[0019] 6) Product collection and analysis system: The products generated by the ferroelectric photocatalytic reaction flow out through the gas outlet, are collected by the gas collector, and then the product composition and content are collected, tested, and analyzed online using gas chromatography.

[0020] This invention utilizes a ferroelectric photocatalyst to construct a carbon dioxide conversion system, comprehensively coordinating and improving the reduction efficiency of the ferroelectric photocatalyst, thereby maximizing the resource utilization of low-concentration carbon dioxide and low-frequency airflow in flue gas, which has important environmental and economic significance. The invention utilizes ferroelectric photocatalytic reaction technology, and by adjusting the flow controller, humidifier, turbine blades, solar simulator, etc. to change the pressure and frequency of the catalytic reaction, the content of the sacrificial agent, and the intensity of light, fully utilizing the low-concentration carbon dioxide in the flue gas, achieving high-value-added waste gas from high-energy-consuming industries and optimizing the energy structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology of the present invention.

[0022] Figure 2 It is a schematic diagram of the corona polarization device of the present invention.

[0023] Figure 3 Schematic diagram of the spiral spoiler of the present invention.

[0024] Figure 4 It is a schematic diagram of the reaction vessel of the present invention and a simulation diagram of the pressure inside the reactor.

[0025] Figure 5 1 is a graph showing the yield of carbon monoxide under different reaction conditions according to the present invention.

[0026] In the figure, 1. flue gas buffer bottle, 2. flow controller, 3. carbon dioxide concentration detector, 4. humidity controller, 5. check valve, 6. flow controller, 7. turbine blade, 8. lower reaction chamber, 9. sample carrying sieve, 10. ferroelectric photocatalyst, 11. solar simulator, 12. gas outlet, 13. gas collector, 14. gas chromatograph, 15. carbon dioxide reactor, 16. upper reaction chamber. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings of specific embodiments.

[0028] See also Figure 1 The device of the present invention comprises a flue gas buffer bottle 1, a carbon dioxide concentration detector 3 with an accuracy of ±0.5%, and a carbon dioxide reactor 15, which are connected in sequence. The inlet of the flue gas buffer bottle 1 is connected to the smoke pipe, and a flow controller 2 is installed on the pipe between the flue gas buffer bottle 1 and the carbon dioxide concentration detector 3. A humidity controller 4, a check valve 5 for one-way flow of flue gas, and a flow controller 6 are installed in sequence on the pipe between the carbon dioxide concentration detector 3 and the carbon dioxide reactor 15. The carbon dioxide reactor 15 comprises a shell and a ferroelectric body arranged in the shell. The sample-carrying sieve 9 of the photocatalyst 10 divides the carbon dioxide reactor 15 into a lower reaction chamber 8 and an upper reaction chamber 16. The inlet of the lower reaction chamber 8 is installed with a turbine blade 7. The top of the carbon dioxide reactor 15 is sealed with a sealing piece of transparent material. The top of the upper reaction chamber 16 is provided with a solar simulator 11. The side wall of the upper reaction chamber 16 is provided with an outlet 12 connected to the gas collector 13. The air inlet of the gas collection tank 13 extends to the bottom of the gas collection tank 13, and the air outlet is provided at the bottle mouth and is connected to the gas chromatograph 14.

[0029] In the present invention, the ferroelectric photocatalyst 10 used is preferably a ferroelectric semiconductor photocatalyst after corona poling. Figure 2 As shown. Figure 2 In the process, the prepared ferroelectric photocatalyst is placed directly below the metal thimble, and then the thimble is fixed, and the distance between the needle tip and the sample is adjusted to 1 cm. The other end of the thimble is connected to a high-voltage DC power supply. Depending on the ferroelectric properties of the ferroelectric photocatalyst, the voltage is preferably 5kV, 10kV, 15kV, or 20kV. The sample is treated for 30 minutes to obtain samples with different degrees of polarization.

[0030] Changing the frequency of the high-speed flue gas flow in the reaction chamber is achieved by a movable turbine blade 7, which is specifically as follows: Figure 3 By changing the number and size of the propeller blades, the frequency of the flue gas flow reaching the ferroelectric catalyst surface can be controlled.

[0031] In the present invention, the flue gas passes through the surface of the ferroelectric photocatalyst 10 in the reaction chamber at a certain flow rate, and flue gas with different flow rates causes different pressures on the catalyst surface. Figure 4 The model shows that the photocatalytic reaction system has a diameter of D = 6-20 mm, a tube length of L = 50 mm, and a catalyst thickness of ΔL = 5-15 mm in the middle. In this reactor, the bottom is the inlet and the upper right corner is the outlet. The gas flow rate is 50-100 m / s. By constructing the model in COMSOL and using the steady-state solver to obtain the pressure distribution diagram in the reaction vessel, P is calculated. in 、P out And the pressure on the catalyst surface ΔP=P in -P out ; Based on the pressure difference on the catalyst surface, the piezoelectric potential generated by the flue gas flow on the catalyst surface is calculated, thereby predicting the effect of the flue gas flow velocity on the carbon dioxide photoreduction performance of the ferroelectric catalyst.

[0032] The method for converting carbon dioxide in flue gas of the present invention is as follows:

[0033] 1) Flue gas flow control system: Flue gas is charged into a flue gas buffer bottle 1, and the flow rate of the flue gas is controlled to 20-50 m / s by a flow controller 2. The carbon dioxide content in the flue gas is then detected by a carbon dioxide concentration detector 3 to obtain the amount of the ferroelectric photocatalyst 10.

[0034] 2) Humidity control system: The flue gas enters the humidity controller 4 at a uniform speed to adjust the relative humidity of the flue gas to 20% to 50%;

[0035] 3) Wind speed and frequency control system: After humidification, the flue gas enters the flow controller 6 through the check valve 5, and the flow controller 6 adjusts the flow rate of the humidified flue gas to 50-100 m / s;

[0036] 4) Frequency control: The flue gas after the flow rate is adjusted by the flow controller 6 is adjusted to 0-10 under the action of the turbine blade 7. 5 The spiral airflow of Hz provides a continuous dynamic pressure on the surface of the ferroelectric photocatalyst 10;

[0037] 5) Catalytic Reaction System: A ferroelectric photocatalyst 10 is laid flat on a sample-carrying sieve 9, and the intensity of a solar simulator 11 is adjusted to irradiate light vertically from above and below the surface of the ferroelectric photocatalyst 10. Under the action of the light radiation and the spiral humidified flue gas flow, the ferroelectric photocatalytic carbon dioxide reduction reaction occurs;

[0038] 6) Product collection and analysis system: The product generated by the ferroelectric photocatalytic reaction flows out through the gas outlet 12, is collected by the gas collector 13, and then is collected, tested, and analyzed online by the gas chromatograph 14 for product composition and content.

[0039] The present application utilizes ferroelectric semiconductor photocatalyst and mechanical energy, solar energy to carry out catalytic carbon dioxide reduction technology, and it adopts a kind of green, sustainable carbon dioxide chemical conversion method. The ferroelectric photocatalytic carbon dioxide reduction technology utilizes the ferroelectric semiconductor material with suitable energy band structure to convert the absorbed photons into photoexcitons, and photoexcitons are separated into carriers (i.e. electrons and holes), and electrons and holes are respectively transmitted to the surface of the catalyst, and reduction and oxidation reactions occur with carbon dioxide and water to generate carbon monoxide, hydrocarbon products, oxygen, etc. At the same time, under the action of external mechanical force, the size of the built-in electric field can be formed inside the ferroelectric semiconductor material, and the external electric field can control the direction and amplitude of polarization, regulate the local energy band bending degree of the ferroelectric reaction species interface, realize surface properties and dynamic control of catalytic redox reaction; The polarization effect contained by the ferroelectric semiconductor material can be coupled with the photocatalytic effect, promote the rapid migration of electrons and holes, extend its life, and make the photocatalytic carbon dioxide conversion efficiency of the ferroelectric semiconductor material improve.

[0040] The catalytic system of the carbon dioxide reduction device based on ferroelectric photocatalytic technology of the present invention is a gas phase system. It utilizes ferroelectric photocatalytic carbon dioxide reduction, and its catalytic reaction occurs at the gas-solid interface of carbon dioxide and the catalyst, which can achieve and achieve enhanced catalytic efficiency and improved product selectivity.

[0041] The present invention utilizes the coupling of the ferroelectric effect and the photocatalytic effect of the ferroelectric semiconductor to promote the reduction efficiency of carbon dioxide in the flue gas, and still has high catalytic efficiency and product selectivity under low concentration carbon dioxide gas.

[0042] Figure 5 This is a graph showing the carbon monoxide yield of the carbon dioxide reduction device based on ferroelectric photocatalytic technology, where the catalyst is barium titanate. Figure 5 It can be shown intuitively that solar radiation, humidity, flue gas velocity and frequency all have a positive impact on carbon monoxide production.

[0043] In summary, the ferroelectric photocatalytic carbon dioxide reduction device of the present invention has the following beneficial effects compared with the prior art:

[0044] First, the present invention proposes a carbon dioxide reduction device based on ferroelectric photocatalytic technology and its manufacturing and use technology. The carbon dioxide reduction device is used for ferroelectric photocatalytic reduction of carbon dioxide in flue gas and has a simple structure and low price.

[0045] Second, the ferroelectric photocatalytic carbon dioxide reduction device proposed in the present invention can enable the carbon dioxide reduction reaction to proceed efficiently and stably. Under the action of a larger airflow velocity and a higher airflow frequency, the product yield is greater and the selectivity is higher.

[0046] Third, the ferroelectric photocatalytic carbon dioxide reduction device proposed in the present invention can be applied to carbon dioxide photoreduction of flue gas, carbon dioxide thermal reduction, nitrogen photoreduction, methane production, carbon monoxide production, etc.; compared with existing devices, it has a wider range of applications.

[0047] In particular, the ferroelectric photocatalytic reaction of the carbon dioxide reduction device proposed by the present invention occurs at the gas-solid interface between carbon dioxide and the catalyst, which can achieve and achieve enhanced photocatalytic efficiency and improved product selectivity.

Claims

1. A reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology, characterized in that: The invention comprises a flue gas buffer bottle (1), a carbon dioxide concentration detector (3), and a carbon dioxide reactor (15) which are connected in sequence. The inlet of the flue gas buffer bottle (1) is connected to the incoming smoke pipe. A flow controller (2) is installed on the pipe between the flue gas buffer bottle (1) and the carbon dioxide concentration detector (3). A humidity controller (4) and a flow controller (6) are installed in sequence on the pipe between the carbon dioxide concentration detector (3) and the carbon dioxide reactor (15). The carbon dioxide reactor (15) comprises a shell and a A sample-carrying sieve (9) for placing a ferroelectric photocatalyst (10) is provided. The sample-carrying sieve (9) divides a carbon dioxide reactor (15) into a lower reaction chamber (8) and an upper reaction chamber (16). A turbine blade (7) is installed at the inlet of the lower reaction chamber (8). A solar simulator (11) is provided at the top of the upper reaction chamber (16). An outlet (12) connected to a gas collector (13) is provided on the side wall of the upper reaction chamber (16). A gas chromatograph (14) is also installed on the outlet of the gas collector (13).

2. The reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology according to claim 1, characterized in that: A check valve (5) is installed between the humidity controller (4) and the flow controller (6) to allow the smoke to flow in one direction.

3. The reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology according to claim 1, characterized in that: The top of the carbon dioxide reactor (15) is sealed with a sealing sheet made of a transparent material.

4. The reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology according to claim 1, characterized in that: The air inlet of the gas collector (13) extends to the bottom of the gas collector (13), and the air outlet is arranged at the bottle mouth.

5. The reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology according to claim 1, characterized in that: The ferroelectric photocatalyst (10) is a ferroelectric photocatalyst that has been subjected to corona polarization in an external electric field.

6. The reaction device for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology according to claim 1, characterized in that: The accuracy of the carbon dioxide concentration detector (3) should reach ±0.5%.

7. A method for converting carbon dioxide in flue gas based on ferroelectric photocatalytic technology using the device according to any one of claims 1 to 6, characterized in that: include 1) Flue gas flow control: Flue gas is charged into a flue gas buffer bottle (1), and the flow rate of the flue gas is controlled to be 20-50 m / s by a flow controller (2). The carbon dioxide content in the flue gas is then detected by a carbon dioxide concentration detector (3) to obtain the amount of the ferroelectric photocatalyst (10); 2) Humidity control: The flue gas enters the humidity controller (4) at a uniform speed to adjust the relative humidity of the flue gas to 20% to 50%; 3) Wind speed control: After being humidified, the flue gas enters the flow controller (6) through the check valve (5), and the flow controller (6) adjusts the flow rate of the humidified flue gas to 50-100 m / s; 4) Frequency control: The flue gas after the flow rate is adjusted by the flow controller (6) is adjusted to 0-10 under the action of the turbine blade (7). 5 The spiral airflow of Hz provides a continuous dynamic pressure on the surface of the ferroelectric photocatalyst (10); 5) Catalytic reaction: the ferroelectric photocatalyst (10) is spread flat on the sample supporting sieve (9), and the intensity of the solar simulator (11) is adjusted to irradiate light vertically from top to bottom on the surface of the ferroelectric photocatalyst (10); under the action of light radiation and spiral humidified flue gas flow, the ferroelectric photocatalytic carbon dioxide reduction reaction occurs; 6) Product collection and analysis: The product generated by the ferroelectric photocatalytic reaction flows out through the gas outlet (12), is collected by the gas collector (13), and then is collected, tested, and analyzed online using a gas chromatograph (14).

Images