Gas-solid fluidized bed reactor and method for photo-thermal coupling catalysis of CO2 reduction

Abstract

The invention provides a gas-solid fluidized bed reactor and method for photo-thermal coupling catalysis of CO2 reduction. The gas-solid fluidized bed reactor comprises a reactor main body, a gas inlet base and a heating part, a reaction cavity in the reactor main body is an inverted circular truncated cone-shaped cavity, and a quartz light window is arranged at the top of the reaction cavity; a columnar gas channel is arranged in the gas inlet base; the bottom of the reactor main body is connected with the top of the air inlet base, and a porous sieve plate is arranged between the reactor main body and the air inlet base; the bottom of the inverted circular truncated cone-shaped cavity is communicated with the top of the columnar gas channel through a porous sieve plate; the heating part is used for providing heat for the reactor main body and the air inlet base. According to the photo-thermal reactor, light blocking caused by catalyst accumulation of a traditional photo-thermal reactor is reduced, the contact area of reactant gas and the catalyst is effectively increased, and the efficiency of the catalyst is fully exerted.

Description

Technical Field

[0001] The present invention belongs to solar energy utilization and CO 2 Reduction field, particularly a method for photothermal coupled catalytic CO 2 Gas-solid fluidized bed reactor and method for reduction. Background Art

[0002] Using clean, renewable solar energy to convert CO 2 As one of the key technologies that can effectively solve the energy crisis and alleviate environmental problems, the research on converting CO into high value-added chemicals or hydrocarbon fuels has been carried out in depth around the world. 2 Reduction is based on the principle of photocatalysis. By introducing external additional heat while simulating sunlight irradiation, the activation energy of the reactants is reduced and the energy required to cross the reaction energy barrier is provided, achieving efficient CO reduction. 2 Compared with traditional photocatalysis, photothermal catalysis involves additional heat input, so from a kinetic point of view, CO 2 The reduction reaction is an endothermic reaction, and heating can push the reaction in the positive direction. From a thermodynamic point of view, the higher the temperature, the more negative the ΔG value, and the easier it is for the reaction to proceed spontaneously, thereby significantly increasing the CO 2 Moreover, the photothermal synergistic catalysis of CO 2 Since reduction technology can adjust the temperature, it is beneficial to the flexible control of reaction selectivity, thereby achieving the targeted preparation of the target product.

[0003] At present, the photothermal coupled catalytic CO 2 The research on reduction is mainly focused on the synthesis and regulation of new photothermal catalysts to reduce carrier recombination and extend the life of the catalyst. In addition, the design and optimization of photothermal catalytic reactors are also key research topics in the field of photothermal coupled catalysis. Existing solar photothermal coupled catalytic reactors are mostly bottom-heated fixed-bed microreactors, which achieve smaller mass transfer distances and higher heat transfer efficiency. However, there are still many problems due to the volume of the cavity and the limitations of the fixed state of the catalyst. The main problems include: (1) Regardless of whether the photocatalyst powder is spread, sprayed or fixed on a porous substrate, experiments have shown that the light cannot fully penetrate into the catalyst and can only irradiate to a depth of about 80 μm below the catalyst surface. As a result, the number of catalysts actually participating in the catalytic reaction is significantly reduced, and the utilization efficiency of light energy is low, which limits the progress of the photocatalytic reaction and reduces the reduction efficiency. (2) The fixed bed loading method limits the contact between the catalyst particles and the reaction gas, that is, the CO2-carrying 2 The water vapor passes through the cavity from the catalyst surface with less resistance, resulting in a decrease in the utilization rate of the catalyst. (3) CO 2 and H2 The residence time of O in the microreactor is short, the reaction is incomplete, the mass transfer efficiency decreases, and the product distribution is not ideal.

[0004] Therefore, it is necessary to design a multiphase reaction device that can efficiently utilize solar energy and improve the mass transfer and heat transfer effects in the photothermal catalytic process. 2 Improving the reduction reaction effect is of great significance. Summary of the invention

[0005] In order to solve the above-mentioned problems of the prior art, the present invention provides a method for photothermal coupled catalytic CO 2 The reduced gas-solid fluidized bed reactor and method reduce the light obstruction caused by catalyst accumulation in traditional photothermal reactors, effectively increase the contact area between reactant gas and catalyst, and give full play to the efficiency of the catalyst.

[0006] The present invention is achieved through the following technical solutions: A method for photothermal coupled catalytic CO 2 A reducing gas-solid fluidized bed reactor comprises: a reactor body, an air inlet base and a heating component; the reaction chamber inside the reactor body is an inverted truncated cone-shaped cavity with a quartz light window on the top; a columnar gas channel is arranged in the air inlet base; the bottom of the reactor body is connected to the top of the air inlet base, and a porous sieve plate is arranged between the reactor body and the air inlet base; the bottom of the inverted truncated cone-shaped cavity is connected to the top of the columnar gas channel through the porous sieve plate; the heating component is used to provide heat for the reactor body and the air inlet base.

[0007] Preferably, the inner wall of the reactor body is coated with a reflective coating.

[0008] Preferably, the distance between the bottom of the reactor body and the quartz light window satisfies: H = H 1 + H 2 + H 3 + H 4 H 1 = 2H mf

[0009]

[0010] < u <

[0011]

[0012]

[0013]

[0014]

[0015] H 2 =2

[0016] D T1 =

[0017] H 3 =D t ×1 / 3

[0018] Among them, H 1 is the height of dense phase; H 2 H is the height of the dilute phase; 3 H is the height of the expansion section; 4 is the transition section height; H mf is the static bed height; is the mass of the catalyst on the porous sieve plate; is the catalyst packing density; is the bed diameter of the dense phase; V is the volume flow rate of the reactant gas; u is the operating gas velocity of the reactor; u mf is the initial fluidization gas velocity; u 0 is the gas velocity when the catalyst is taken out; is the agglomerated particle size of the catalyst; is the average density of the catalyst; ρ is the reactant gas density; is the acceleration due to gravity; μ m is the viscosity of the reactant gas; y i is the mole fraction of component i in the reactant gas; μ i is the viscosity of pure component i at normal pressure; M i is the molecular weight of component i in the reactant gas; is the density of component i in the reactant gas at the reaction temperature; D T1 D is the dilute phase bed diameter; t is the diameter of the expansion section, i.e. the inner diameter of the top surface of the reactor body; α is the transition angle of the transition part between the reaction section and the expansion section.

[0019] Furthermore, the distance between the bottom of the reactor body and the quartz light window is 5-15 cm, the inner diameter of the bottom surface of the reactor body is 1-5 cm, and the inner diameter of the top surface of the reactor body is 5-10 cm.

[0020] Furthermore, a product outlet is provided on the upper side of the reactor body, the vertical distance between the product outlet and the bottom surface of the quartz light window is 1-5 cm, and the aperture of the product outlet is 1-5 cm.

[0021] Preferably, the pores on the porous sieve plate are evenly distributed, the average pore size of the pores is 20-100 μm, and the thickness of the porous sieve plate is 0.5-5 mm.

[0022] Preferably, the heating component is a heating jacket, and the outside of the reactor body and the air inlet base are both provided with heating jackets.

[0023] Preferably, the thickness of the quartz light window is 3-6 mm.

[0024] A photothermal coupled catalytic CO 2 The reduction method, based on the gas-solid fluidized bed reactor as described above, comprises: After preheating, the reactant gas enters the reaction chamber of the reactor body through the columnar gas channel and the porous sieve plate. By adjusting the gas velocity of the reactant gas, the catalyst particles on the porous sieve plate are placed in a suspended state, so that light is incident from the quartz light window onto the surface of the catalyst particles to drive the reaction, and heating is performed at the same time.

[0025] Preferably, the photothermal coupled catalytic CO 2 In the reduction method, the gas velocity of the reactant gas u satisfy: < u <

[0026]

[0027]

[0028]

[0029]

[0030] Among them, u mf is the initial fluidization gas velocity; u 0 is the gas velocity when the catalyst is taken out; is the agglomerated particle size of the catalyst; is the average density of the catalyst; ρ is the reactant gas density; is the acceleration due to gravity; μ m is the viscosity of the reactant gas; y i is the mole fraction of component i in the reactant gas; μ iis the viscosity of pure component i at normal pressure; M i is the molecular weight of component i in the reactant gas; is the density of component i in the reactant gas at the reaction temperature.

[0031] Compared with the prior art, the present invention has the following beneficial effects: The present invention is used for photothermal catalysis of CO 2 The reaction chamber in the reduced gas-solid fluidized bed reactor is in the shape of an inverted truncated cone. A porous sieve plate is used to carry the catalyst, which also serves as a gas distributor and a light-transmitting quartz window is set. During operation, the flow rate of the reactant gas is controlled to keep the catalyst particles in a circulating suspended fluidized state. Thus, the light blocking caused by catalyst accumulation in traditional photothermal reactors is reduced, and the contact area between light and reactants and catalysts is effectively increased, thereby significantly improving the system's efficiency in utilizing light and heat energy. At the same time, the contact time between catalyst particles and CO is effectively extended. 2 The contact time of the reaction gases such as water vapor and water vapor is shortened, so that the reaction can fully occur and the catalyst can be fully utilized; and the fluidization and bubble disturbance of the catalyst particles make the catalyst particles evenly mixed and the contact probability is increased, the mass transfer coefficient is significantly improved, and the mass transfer limitation of the reactants on the catalytic interface is overcome, thereby improving the CO 2 The activity of the reduction reaction and the overall energy conversion efficiency of the system. Because of the existence of the fluidized state, the temperature in the reaction chamber is easy to maintain uniform, which can effectively reduce the condensation of water vapor. In addition, compared with the currently used micro-reactors, the fluidized bed reactor of the present invention can load more catalysts and significantly increase the processing capacity. It is a preliminary attempt at the future industrialization of photothermal catalysis. It should also be noted that the inverted truncated cone-shaped reaction chamber can cause the flow rate of the incoming gas to drop sharply, so that no backflow will occur inside the cavity, and the catalyst particles will not be carried out of the cavity by the airflow to block the pipeline. The present invention has a wide range of applications, high solar energy utilization, and CO 2 The reduction reaction has the advantages of high efficiency and can realize the photothermal coupling catalysis of CO2 driven by full spectrum solar energy. 2 Reduction reaction.

[0032] Furthermore, the inner wall of the reactor body of the present invention has a reflective effect, and because the reaction cavity inside the reactor body is an inverted truncated cone-shaped cavity, that is, the inner wall is inclined, the light incident from the quartz light window to the inner wall surface of the reactor body can be reflected into the reaction cavity, thereby improving the utilization rate of sunlight. In particular, when the sunlight is not incident vertically, the light can be reflected on the catalyst surface through the reflective coating, thereby allowing the sunlight to be incident from a direction with a certain angle to the axis of the reactor body, thereby utilizing sunlight all day long.

[0033] Furthermore, the present invention performs strict design calculations on the distance between the bottom of the reactor body and the quartz light window according to the operating gas velocity and the physical properties of the catalyst and reactant gases, so that the distance can meet the operating requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 The present invention is a method for solar photothermal coupling catalysis of CO 2 The overall structural layout diagram of the reduced gas-solid fluidized bed reactor; Figure 2 The present invention is a method for solar photothermal coupling catalysis of CO 2 A cross-sectional view of a reactor body in a reduced gas-solid fluidized bed reactor; Figure 3 The present invention is a method for solar photothermal coupling catalysis of CO 2 Schematic diagram of the components of the reactor body in the reduced gas-solid fluidized bed reactor; Figure 4 The present invention is a method for solar photothermal coupling catalysis of CO 2 Cross-sectional view of the gas inlet base in a reduced gas-solid fluidized bed reactor. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0037] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0038] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0039] In addition, it should be noted that the terms "first", "second", etc. of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. The orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements.

[0040] like Figure 1 As shown, the photothermal coupled catalytic CO 2 A reduced gas-solid fluidized bed reactor comprising: The reactor body 5 has an inverted truncated cone-shaped cavity inside and a quartz light window 3 is arranged on the top; An air inlet base 7, connected to the bottom of the reactor body 5, and a columnar gas channel 9 is provided in the air flow passage portion; A porous sieve plate is installed between the reactor body 5 and the gas inlet base 7, and connects the inverted truncated cone-shaped cavity with the columnar gas channel 9; The heating component is used to provide heat to the reactor body 5 and the gas inlet base 7.

[0041] The vertical distance between the bottom of the reactor body 5 and the quartz light window 3 is calculated as follows: (1) The operating conditions are set as follows: Reaction temperature: 300°C, reaction pressure: 1 atm, catalyst (In2 O 3 / WO 3 ), agglomerate particle size: 0.5-30 μm, catalyst average density: 4.26 g / cm 3 , catalyst packing density: 318.47 kg / m 3 , catalytic performance: CO yield> 90%, reactor design processing capacity: 0.000002465 m 3 / s, inner diameter of the reactor body top surface D t : 54.5 mm.

[0042] (2) Calculation of operating gas velocity: Assume that 30% of the reactant gas is water vapor and 70% is CO 2 (mole fraction), temperature: 300℃, maximum size of catalyst agglomerate particles: 30 μm.

[0043] 1) Reactant gas viscosity μ m (estimated from the collinear diagram of gas viscosity at normal pressure): mPa·s y i : The mole fraction of component i in the reactant gas, i=1,2; μ i : Viscosity of pure component i at normal pressure; M i : The molecular weight of component i in the reactant gas.

[0044] 2) Density of reactant gas ρ :

[0045] : The density of component i in the reactant gas at the reaction temperature.

[0046] 3) Initial fluidization gas velocity u mf : =0.00088m / s : The maximum value of the catalyst agglomerate particle size; : Average density of catalyst; : acceleration due to gravity (9.81 N / kg).

[0047] 4) Gas velocity u when the catalyst is taken out 0 : 0.08068m / s Therefore, under the above operating conditions, the operating gas velocity of the fluidized bed reactor is u Need to meet: < u < , with an operating gas velocity of 0.01 m / s (CO 2 The vertical distance between the bottom of the reactor body 5 and the quartz light window 3 is calculated by taking the inlet gas flow rate of 467 sccm) as an example.

[0048] (3) Calculation of the vertical distance between the bottom of the reactor body 5 and the quartz light window 3 1) Calculation of the bed diameter of the dense phase (i.e. the inner diameter of the bottom of the reactor body 5)

[0049] V: reactant gas volume flow rate, i.e. reactor design processing capacity: 0.000002465m 3 / s; At this time, the gas velocity at the top of the reactor is u top : =0.001057 m / s < u top < Therefore, when the operating gas velocity is 0.01 m / s, the gas velocity at the top of the reactor is within the allowable range, which can achieve fluidization without carrying out the catalyst, indicating that the selected operating gas velocity of 0.01 m / s meets the requirements.

[0050] 2) Bed height calculation (such as Figure 3 ) Static bed height: H mf

[0051] Dense phase height: H 1 = 2H mf =0.001274 m At this time, the minimum bed diameter of the dilute phase is: D T1 = =0.0229 m Dilute phase height: H 2 =2 = 0.0457 m So the height of the reaction section is: H 1 + H 2 ≈ 0.05 m The height of the expansion section is one third of the diameter of the expansion section (i.e., the inner diameter of the top surface of the reactor body), i.e., H 3 =0.0545×1 / 3 = 0.0182 m Transition angle between the reaction section and the expansion section It can be 101°, then the height of the transition section is:

[0052] Therefore, the distance from the bottom of the reactor body to the quartz light window (fluidized bed height) is: H = H 1 + H 2 + H 3 + H 4 =0.02+0.05+0.0182+0.0078≈ 0.10 m According to the above calculation process, under the following operating conditions: reaction temperature 300 ° C, reaction pressure 1 atm, catalyst (In 2 O 3 / WO 3 ), agglomerated particle size 0.5-30 μm, average catalyst density 4.26 g / cm 3 , catalyst packing density 318.47kg / m 3 , catalytic performance CO yield>90%, reactor design processing capacity 0.000002465 m 3 / s, inner diameter of the reactor body top surface D t 54.5 mm; when CO 2 The inlet gas velocity is 300-700 sccm, that is, the operating gas velocity of the fluidized bed during operation is in the range of 6-15 mm / s, and the vertical distance between the bottom of the reactor body 5 and the quartz light window (that is, the height of the fluidized bed) is 5-15 cm.

[0053] In the present invention, the inner diameter of the bottom surface of the reactor body 5 is preferably 1-5 cm, and the inner diameter of the top surface of the reactor body 5 is preferably 5-10 cm.

[0054] In some embodiments of the present invention, the inner wall of the reactor body 5 is coated with a high temperature resistant reflective coating, which transforms the point light source into a surface light source, makes the light uniform, and improves the light utilization efficiency.

[0055] In some embodiments of the present invention, the quartz light window 3 is fixedly connected to the reactor body 5 by means of a flat head 1, and ceramic gaskets are provided between the flat head 1 and the quartz light window 3 and between the quartz light window 3 and the reactor body 5 to ensure a sealed connection.

[0056] In some embodiments of the present invention, the upper side of the reactor body 5 is provided with a product outlet 4 ( Figure 2 ), 1-5 cm away from the lower bottom surface of the quartz light window 3, and the aperture of the product outlet 4 is 1-5 cm.

[0057] In some embodiments of the present invention, the pores on the porous sieve plate 6 are evenly distributed and concentrated, with an average pore size of 20-100 μm and a thickness of 0.5-5 mm, ensuring that the airflow is evenly dispersed and fully in contact with the loaded catalyst.

[0058] In some embodiments of the present invention, a sieve plate base 10 ( Figure 4 ), the porous sieve plate 6 carrying the catalyst is placed on the sieve plate base 10. During assembly, the porous sieve plate 6 carrying the catalyst and the reactor body 5 as well as the porous sieve plate 6 and the sieve plate base 10 are fixed with ceramic gaskets to ensure sealing.

[0059] In some embodiments of the present invention, the reactor body 5 is connected to the flat plate head 1 and the air inlet base by flanges and fixed by screws.

[0060] In some embodiments of the present invention, the heating component is in the form of a heating jacket, and the outside of the reactor body and the air inlet base are equipped with a detachable heating jacket, which, in addition to providing heat, is also used to ensure that water continues to participate in the reaction process in the form of steam.

[0061] In some embodiments of the present invention, the porous sieve plate 6 may be made of quartz, ceramic, or stainless steel.

[0062] The thickness of the quartz light window 3 of the present invention is 3-6 mm. The quartz light window 3 of a certain thickness provides protection for a high-pressure environment.

[0063] When the reactor of the present invention is used, the average particle size of the catalyst particles is 0.5-150 μm, and the catalyst particles are loosely spread over the entire porous sieve plate; the reactant gas can be H 2 O / CO 2 or H 2 / CO 2 A mixed gas of which CO 2 The mole fraction is not less than 50%.

[0064] The present invention is used for photothermal coupling catalysis of CO 2 The operation of the reducing gas-solid fluidized bed reactor includes the following steps: the preheated reactant gas enters the reactor body 5 through the columnar gas channel 9 of the gas inlet base 7, is dispersed by the porous sieve plate 6, and the gas velocity of the reactant gas is adjusted to make the catalyst particles in a suspended state to participate in the reaction. Light is incident from the quartz light window to the catalyst surface to drive the reaction, and heating is performed by a heating component.

[0065] Based on the gas-solid fluidized bed reactor as described above, the present invention uses photothermal coupled catalytic CO 2 The restoration method includes the following steps: CO 2 The water vapor formed by heating enters the reaction chamber through the columnar gas channel 9 in the form of bubbles through the bubble dispersion tube, and is dispersed through the porous sieve plate 6. By adjusting the gas velocity of the reactant gas, the catalyst particles are in a suspended fluidized state to participate in the reaction; The light is incident from the quartz light window 3 onto the surface of the catalyst particles, providing the light energy required for the reaction and driving the reaction. At the same time, the reactor body 5 and the air inlet base 7 are heated to provide the heat required for the reaction and keep the water in the form of steam. The obtained product first enters the condensation system through the product outlet 4, so that the liquid phase product is condensed into the water phase and separated from the gas phase product. The gas phase product passes through a drying tube and enters the gas chromatography for qualitative and quantitative analysis.

[0066] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0067] Example 1 See also Figures 1 to 4 As shown, this embodiment provides a method for solar thermal coupling catalytic CO 2 The reducing gas-solid fluidized bed reactor comprises a flat head 1, a ceramic gasket 2, a quartz light window 3, a product outlet 4, a reactor body 5, a porous sieve plate 6, an air inlet base 7, a heating jacket 8, a columnar gas channel 9, and a sieve plate base 10.

[0068] The reaction chamber inside the reactor body 5 is an inverted truncated cone-shaped cavity, and the inner wall is coated with a high-temperature resistant reflective coating; the air inlet base 7 is placed at the bottom of the reactor body 5; the porous sieve plate 6 is installed between the reactor body 5 and the air inlet base 7; a columnar gas channel 9 is arranged in the air flow passage part of the air inlet base 7; a sieve plate base 10 is arranged at the upper end of the air inlet base 7, and the porous sieve plate 6 loaded with catalyst is placed on the sieve plate base 10. During assembly, the porous sieve plate 6 loaded with catalyst is fixed to the reactor body 5 and the sieve plate base 10 with a ceramic gasket 2; the outside of the reactor body 5 and the air inlet base 7 are both provided with a detachable heating sleeve 8.

[0069] In this embodiment, the distance between the bottom of the reactor body 5 and the quartz light window 3 is 5 cm, the inner diameter of the bottom surface of the reactor body 5 is 1 cm, the inner diameter of the top surface of the reactor body 5 is 5 cm, the distance between the product outlet 4 and the lower bottom surface of the quartz light window 3 is 1 cm, and the aperture of the product outlet 4 is 1 cm; CO during the operation of the reactor 2 The inlet gas velocity is 300 sccm, that is, the operating gas velocity of the fluidized bed during operation is 6 mm / s. The average pore size of the pores on the porous sieve plate 6 is 20 μm and the thickness is 0.5 mm, ensuring that the gas flow is evenly dispersed and fully contacts the loaded catalyst.

[0070] The catalyst used in this example is TiO 2 / BiVO 3 Nanoparticles with an average particle size of 30 μm, the catalyst particles are loosely spread over the entire porous sieve plate 6; the reactant gas is H 2 O / CO 2 A mixed gas of which CO 2 The volume concentration is 80%, and the reaction temperature is 180° C. The porous sieve plate 6 is made of quartz.

[0071] During operation, the following steps are included: the preheated reactant gas is brought into the reactor body 5 through the air inlet base 7, dispersed through the porous sieve plate 6, and the flow rate of the reactant gas is adjusted to make the catalyst particles in a fluidized state to participate in the reaction. Light is incident from the quartz light window 3 to the catalyst surface to drive the reaction, and the reactor body 5 and the air inlet base 7 are heated by the heating sleeve 8.

[0072] During the test, the simulated sunlight light source was turned on after 0.5 h of ventilation, and the produced gas was introduced into the gas chromatograph through the product outlet 4 for continuous online detection. The test time was 1 h.

[0073] Since the inner wall of the reactor body 5 is provided with a reflective coating, the light incident on the inner wall of the reactor body 5 can be reflected on the catalyst surface, thereby improving the light utilization rate. In addition, this design enables the reactor of the present invention to utilize sunlight all day long in actual production. When the sunlight is not incident vertically, the reflective coating can reflect the light on the catalyst surface, thereby allowing the sunlight to be incident from a direction that forms a certain angle with the axis of the reactor body 5.

[0074] Example 2 In this embodiment, the distance between the bottom of the reactor body 5 and the quartz light window is 10 cm, the inner diameter of the bottom surface of the reactor body 5 is 3 cm, the inner diameter of the top surface of the reactor body 5 is 8 cm, the distance between the product outlet 4 and the lower bottom surface of the quartz light window 3 is 3 cm, and the aperture of the product outlet 4 is 4 cm; CO during the operation of the reactor 2The inlet gas velocity is 500 sccm, that is, the operating gas velocity of the fluidized bed during operation is 10 mm / s. The average pore size of the pores on the porous sieve plate 6 is 50 μm and the thickness is 2 mm, ensuring that the gas flow is evenly dispersed and fully contacts the loaded catalyst.

[0075] The catalyst used in this example is In 2 O 3 / WO 3 Composite nanoparticles with an average particle size of 100 μm. The catalyst particles are loosely spread over the entire porous sieve plate 6. The reactant gas is H 2 O / CO 2 A mixed gas of which CO 2 The volume concentration is 60%. The porous sieve plate 6 is made of ceramic sheets. The reaction temperature is 380°C.

[0076] The remaining conditions are the same as those in Example 1.

[0077] Example 3 In this embodiment, the distance between the bottom of the reactor body 5 and the quartz light window is 15 cm, the inner diameter of the bottom surface of the reactor body 5 is 5 cm, the inner diameter of the top surface of the reaction chamber 5 is 10 cm, the distance between the product outlet 4 and the lower bottom surface of the quartz light window 3 is 5 cm, and the aperture of the product outlet 4 is 5 cm; CO during the operation of the reactor 2 The inlet gas velocity is 700 sccm, that is, the operating gas velocity of the fluidized bed during operation is 15 mm / s. The average pore size of the pores on the porous sieve plate 6 is 100 μm and the thickness is 5 mm, ensuring that the gas flow is evenly dispersed and fully contacts the loaded catalyst.

[0078] The catalyst used in this example is CeO 2 / molecular sieve composite nanoparticles, with an average particle size of 150 μm, and the catalyst particles are loosely spread over the entire porous sieve plate 6; the reactant gas is H 2 O / CO 2 A mixed gas of which CO 2 The volume concentration is 70%. The porous sieve plate 6 is made of ceramic sheets. The reaction temperature is 480°C.

[0079] The remaining conditions are the same as those in Example 1.

[0080] A conventional nanoparticle fixed bed reactor, a conventional thin film fixed bed reactor and a fluidized bed reactor without a reflective coating (other conditions were the same as in Example 2) were used as controls. When the average particle size and dosage of the catalyst were the same as in Example 2, photothermal catalytic CO 2 Restore testing.

[0081] Photothermal catalysis of CO 2The reduction test results are shown in Table 1.

[0082] Table 1 Photothermal catalytic CO 2 Reduction test control

[0083] As can be seen from Table 1, compared with the conventional nanoparticle fixed bed reactor and the conventional thin film fixed bed reactor, the photothermal catalytic CO 2 In the reduction test results, both the yield of the reduction product and the light energy conversion efficiency have been improved by more than one order of magnitude, which shows that the present invention has a good effect in photothermal coupling CO 2 Obvious advantages in reduction reaction systems.

[0084] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the present invention should fall within the scope of the present invention.

Claims

1. A gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction, characterized in that: include: A reactor body (5), an air inlet base (7) and a heating component; the reaction chamber inside the reactor body (5) is an inverted truncated cone-shaped cavity, with a quartz light window (3) arranged on the top; a columnar gas channel (9) is arranged inside the air inlet base (7); the bottom of the reactor body (5) is connected to the top of the air inlet base (7), and a porous sieve plate (6) is arranged between the reactor body (5) and the air inlet base (7); the bottom of the inverted truncated cone-shaped cavity is connected to the top of the columnar gas channel (9) through the porous sieve plate (6); and the heating component is used to provide heat for the reactor body (5) and the air inlet base (7).

2. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 1, characterized in that: The inner wall of the reactor body (5) is coated with a reflective coating.

3. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 1, characterized in that: The distance between the bottom of the reactor body (5) and the quartz light window satisfies: H= H1+ H2+ H3+ H4 <h2 style=";text-align:left;direction:ltr">H1 = 2H<h2 style=";text-align:left;direction:ltr"> mf < u < H2 =2 D T1 = H3=D t ×1 / 3 Among them, H1 is the height of the dense phase; H2 is the height of the dilute phase; H3 is the height of the expansion phase; H4 is the height of the transition phase; H mf is the static bed height; is the mass of the catalyst on the porous sieve plate; is the catalyst packing density; is the bed diameter of the dense phase; V is the volume flow rate of the reactant gas; u is the operating gas velocity of the reactor; u mf is the gas velocity of initial fluidization; u0 is the gas velocity when the catalyst is taken out; is the agglomerated particle size of the catalyst; is the average density of the catalyst; ρ is the reactant gas density; is the acceleration due to gravity; μ m is the viscosity of the reactant gas; y i is the mole fraction of component i in the reactant gas; μ i is the viscosity of pure component i at normal pressure; M i is the molecular weight of component i in the reactant gas; is the density of component i in the reactant gas at the reaction temperature; D T1 D is the dilute phase bed diameter; t is the diameter of the expansion section, i.e. the inner diameter of the top surface of the reactor body (5); α is the transition angle of the transition part between the reaction section and the expansion section.

4. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 3, characterized in that: The distance between the bottom of the reactor body (5) and the quartz light window is 5-15 cm, the inner diameter of the bottom surface of the reactor body (5) is 1-5 cm, and the inner diameter of the top surface of the reactor body (5) is 5-10 cm.

5. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 4, characterized in that: A product outlet (4) is provided on the upper side of the reactor body (5); the vertical distance between the product outlet (4) and the bottom surface of the quartz light window (3) is 1-5 cm; and the aperture of the product outlet (4) is 1-5 cm.

6. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 1, characterized in that: The pores on the porous sieve plate (6) are evenly distributed, the average pore size of the pores is 20-100 μm, and the thickness of the porous sieve plate (6) is 0.5-5 mm.

7. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 1, characterized in that: The heating component is a heating jacket, and the outside of the reactor body (5) and the air inlet base (7) are both provided with a heating jacket.

8. The gas-solid fluidized bed reactor for photothermal coupled catalytic CO2 reduction according to claim 1, characterized in that: The thickness of the quartz light window (3) is 3-6 mm.

9. A photothermal coupled catalytic CO2 reduction method, characterized in that: The gas-solid fluidized bed reactor according to any one of claims 1 to 8 comprises: After preheating, the reactant gas enters the reaction chamber of the reactor body (5) through the columnar gas channel (9) and the porous sieve plate (6). By adjusting the gas velocity of the reactant gas, the catalyst particles on the porous sieve plate (6) are placed in a suspended motion state, so that light is incident from the quartz light window (3) onto the surface of the catalyst particles to drive the reaction, and heating is performed by a heating component at the same time.

10. The method for photothermal coupled catalytic CO2 reduction according to claim 9, characterized in that: Reactant gas velocity u satisfy: < u < Among them, u mf is the gas velocity of initial fluidization; u0 is the gas velocity when the catalyst is taken out; is the agglomerated particle size of the catalyst; is the average density of the catalyst; ρ is the reactant gas density; is the acceleration due to gravity; μ m is the viscosity of the reactant gas; y i is the mole fraction of component i in the reactant gas; μ i is the viscosity of pure component i at normal pressure; M i is the molecular weight of component i in the reactant gas; is the density of component i in the reactant gas at the reaction temperature.

Images