A gas-solid coupled fluidized bed reactor, system and method for producing hydrogen

Abstract

The present disclosure relates to a gas-solid coupled fluidized bed reactor, system and method for preparing hydrogen, the gas-solid coupled fluidized bed reactor comprising a reactor shell, the reactor shell comprising, in order from bottom to top, a reaction zone, a diameter expansion section and a settling zone; the reaction zone is provided with a catalytic member, the catalytic member is configured to be able to confine catalyst particles inside the catalytic member, confine adsorbent particles outside the catalytic member, and allow reaction gas to flow into and out of the catalytic member; an adsorbent channel that can accommodate the flow of adsorbent particles is formed between the outer wall of the catalytic member and the inner wall of the reaction zone. The gas-solid coupled fluidized bed of the present disclosure is used in a methane catalytic reforming hydrogen production process to overcome the problem of particle loss when adsorbent particles pass through catalyst particles, and can improve hydrogen production, achieve continuous operation, and does not require separation of catalyst particles and adsorbent particles, further reducing production costs.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of methane enhanced adsorption reforming hydrogen production, in particular, to a gas-solid coupled fluidized bed reactor, system and method for producing hydrogen. BACKGROUND

[0002] Hydrogen is not only an important raw gas for oil refining, chemical industry, metallurgy and other industries, but also a recognized green energy carrier in the future. Hydrogen has two extremely competitive characteristics as a green energy: one is high energy density, the heat value of unit mass is about 4 times that of coal, 3.1 times that of gasoline, and 2.6 times that of natural gas; it can be stored and is carbon-free, and can be flexibly used across time and region compared with electricity. Therefore, in the process of global energy transformation, hydrogen is the best carbon neutral energy carrier.

[0003] Hydrogen is divided into three types according to the source of production: gray hydrogen, blue hydrogen and green hydrogen. Gray hydrogen mainly refers to hydrogen produced by coal, natural gas, coke oven gas, and chlor-alkali tail gas, which will emit a large amount of carbon dioxide during production. Blue hydrogen is mainly produced by fossil fuels such as coal and natural gas, and the produced carbon dioxide is treated by CCUS (carbon capture, utilization and storage) technology, which has less carbon emissions and can achieve carbon neutrality. Green hydrogen is produced by renewable energy such as wind and solar energy, and is considered to have little or no carbon emissions, but the production cost is high. At present, 96% of hydrogen comes from fossil fuels, and hydrogen is produced by steam methane reforming (SMR) or coal gasification technology, which is called gray hydrogen. The process of producing hydrogen has a lower cost, but the highest carbon intensity, so it has the lowest social acceptance.

[0004] Steam Methane Reforming (SME) is currently the largest method for hydrogen production. Methane steam reforming for hydrogen production usually uses a fixed bed reactor. In order to reduce the pressure drop of the reactor, the catalyst generally uses a honeycomb-shaped solid catalyst with a particle diameter of Φ15-20×10-15mm, and the active component is nickel oxide. The hydrogen production process includes a one-stage or two-stage conversion reaction at 800-820℃, the byproduct CO is converted to CO2 at 300-450℃ in two stages, and CO and CO2 are further removed by solvent absorption or methanol washing. The final equilibrium CO2 gas phase content is 15-20%, and the hydrogen content is less than 75%. Subsequently, high-purity industrial hydrogen is obtained by pressure swing adsorption. Methane steam reforming for hydrogen production is a strong endothermic and reversible reaction, which has the disadvantages of high reaction temperature, low hydrogen concentration, multiple steps in the reaction purification process, low production capacity, high investment, etc. in the process; in terms of catalyst, due to the large particle size of the catalyst, there is a temperature gradient in the internal heat transfer, and the catalyst has a short service life and other defects.

[0005] CN100497160A proposes a process of hydrogen production by adsorption enhanced steam methane reforming using a circulating fluidized bed. By using a composite powder solid catalyst, the fluidized continuous operation of reaction and regeneration is realized, effectively solving the shortcomings of low heat and mass transfer rate of fixed bed, but in the regeneration process, nickel is converted into nickel oxide, and nickel oxide does not have the activity of steam methane reforming reaction, and hydrogen is needed to reduce the nickel oxide on the composite catalyst. In addition to the reactor and regenerator, a reducer is also needed, which increases the equipment investment and operation complexity.

[0006] CN1974375A proposes a process and device of hydrogen production by adsorption enhanced steam methane reforming using a fixed bed. The hydrogen production reaction and regeneration of composite catalyst are carried out in different fixed bed reactors, and are used alternately. The device includes a preheater, two or more fixed bed reactors connected in parallel, and a pressure swing adsorption device. The methane and steam outlet of the preheater is connected to the inlet of each fixed bed reactor, and the outlet of each fixed bed reactor is connected to the pressure swing adsorption device and the preheater respectively. In the reaction process, the active component Ni in the catalyst is repeatedly oxidized to NiO in the regeneration process and reduced to Ni in the reaction process, causing energy waste.

[0007] CN103373706A proposes a method and device of hydrogen production by adsorption enhanced steam methane reforming. The method includes: (1) a composite catalyst containing NiO and CaO enters the reforming reactor from the bottom and flows upward, hydrogen and methane enter the reforming reactor from the bottom and react with the composite catalyst, and NiO in the composite catalyst is reduced to Ni; (2) methane and steam enter the reforming reactor from the middle and react with the composite catalyst containing Ni and CaO under steam reforming conditions to generate hydrogen, CO and CO2, and the CO2 reacts with CaO in the composite catalyst to be converted into CaCO3; (3) the reaction product gas and the spent composite catalyst are separated at the top of the reforming reactor, the separated product gas enters the subsequent separation and purification device to obtain high-purity hydrogen, and the separated spent composite catalyst enters the regenerator and is decomposed and regenerated at 700-800℃ to obtain regenerated composite catalyst containing NiO and CaO, which is circulated in the reforming reactor. In the reaction process, the active component Ni in the catalyst is repeatedly oxidized to NiO in the regeneration process and reduced to Ni in the reaction process, causing energy waste.

[0008] CN101559924A proposes a hydrogen production process by steam reforming of methane. Methane and water vapor are mixed with adsorbent in a mixer and then enter a reactor for reaction, and a catalyst is arranged in the reactor. The reacted gas and adsorbent leave the reactor for separation, and part of the adsorbent after separation is calcined for regeneration, and another part of the adsorbent is removed and an equal amount of fresh adsorbent is added, and the adsorbent from the regenerator is mixed in the mixer to realize continuous operation and separation of the catalyst and the adsorbent. This adsorbent is easy to cause local blockage of adsorbent particles in the catalyst bed layer by the way of catalyst fixed bed layer, and once the blockage occurs, the reaction gas is deflected, reducing the reaction efficiency. SUMMARY

[0009] The purpose of the present disclosure is to provide a gas-solid coupled fluidized bed reactor for preparing hydrogen, which is used in a hydrogen production process by catalytic reforming of methane, overcomes the problem of particle loss when adsorbent particles pass through catalyst particles, and can improve hydrogen production, realize continuous operation, and does not need to separate catalyst particles and adsorbent particles, further reducing production cost.

[0010] To achieve the above purpose, the first aspect of the present disclosure provides a gas-solid coupled fluidized bed reactor for preparing hydrogen, which comprises a reactor shell, and the reactor shell comprises, from bottom to top, a reaction zone, a diameter expansion section and a settling zone.

[0011] The reaction zone is provided with a catalytic member, which is configured to be able to restrict catalyst particles inside the catalytic member, restrict adsorbent particles outside the catalytic member, and allow reaction gas to flow into and out of the catalytic member; an adsorbent channel that can accommodate the flow of adsorbent particles is formed between the outer wall of the catalytic member and the inner wall of the reaction zone.

[0012] Optionally, a plurality of catalytic member layers are arranged axially and spaced apart in the reaction zone, and each catalytic member layer comprises a plurality of catalytic members arranged in the same layer; preferably, the shapes and sizes of the plurality of catalytic members are the same.

[0013] Optionally, the number of catalytic member layers is 2-15, and the number of catalytic members in each catalytic member layer is 2-100.

[0014] Optionally, the distance between adjacent catalytic member layers is 20-400 cm; the distance between radially adjacent catalytic members in the axial cross section is 100-500 cm.

[0015] Optionally, in each of the layers of the catalytic members, a space is formed between two adjacent catalytic members to form a sorbent channel in the layer of the catalytic members, the sorbent channel comprising all the spaces in the layer of the catalytic members.

[0016] In a radial cross-section of each of the layers of the catalytic members, a ratio of a cross-sectional area of the sorbent channel to a cross-sectional area of all the catalytic members is (1-3):1.

[0017] Optionally, the catalytic members are formed as catalyst cages, the cage walls of the catalyst cages having apertures configured to prevent passage of catalyst particles and passage of sorbent particles.

[0018] Optionally, the cage walls are formed of a wire mesh, the wire mesh being one or more of a stainless steel wire mesh, a Johnson wire mesh, and a metal powder sintered plate with holes.

[0019] Optionally, the catalyst cages are formed as flat cages and have at least one set of main cage walls arranged in parallel, the wall surfaces of the main cage walls being arranged at an angle to a layer surface of a layer of the catalytic members.

[0020] Optionally, the angle a between the wall surfaces of the main cage walls and the layer surface is 40-85°.

[0021] Optionally, the wall surfaces of the main cage walls have an open area ratio of 40-80%.

[0022] Optionally, in the same layer of the catalytic members, all the catalyst cages have the same axial height and cage thickness, the cage thickness representing a distance between two main cage walls arranged in parallel, and any two adjacent catalyst cages have a space with the same width.

[0023] Optionally, the reactor housing is provided with a sorbent inlet, a sorbent outlet, a raw material gas inlet, and a gas outlet; the raw material gas inlet is arranged at a bottom of the reactor, and the gas outlet is arranged at a top of the settling zone.

[0024] The sorbent outlet and the sorbent inlet are arranged at an upper portion and a lower portion of the reaction zone, respectively, and the catalytic members are arranged between the sorbent inlet and the deactivated sorbent outlet.

[0025] The settling zone is provided with a gas-solid separator, and a gas outlet of the gas-solid separator is in communication with the gas outlet of the reactor.

[0026] The second aspect of the present disclosure provides a system for preparing hydrogen, the system comprising the gas-solid coupled fluidized bed reactor according to the first aspect of the present disclosure.

[0027] Optionally, the system further comprises a CO2 collection device and a sorbent regeneration device.

[0028] The adsorbent regeneration device is provided with a CO2 gas outlet, an inactivated adsorbent inlet and a regenerated adsorbent outlet;

[0029] The inactivated adsorbent inlet is connected with the adsorbent outlet of the gas-solid coupling fluidized bed reactor, the regenerated adsorbent outlet is connected with the adsorbent inlet, and the CO2 gas outlet is connected with the CO2 collection device;

[0030] The adsorbent regeneration device is used for regenerating the inactivated adsorbent;

[0031] Optionally, the temperature of the regeneration treatment is 800-1000℃.

[0032] The third aspect of the present disclosure provides a method for preparing hydrogen by reforming methane, which comprises: introducing a raw gas containing methane and water vapor into the reaction zone of the gas-solid coupling fluidized bed reactor of the first aspect of the present disclosure to contact and react with the catalyst particles in the catalytic member; and introducing adsorbent particles into the reaction zone.

[0033] Optionally, the reaction temperature of the gas-solid coupling fluidized bed reactor is 500-700℃, the operating pressure is 0.1-5.0MPa, the total space velocity of the methane and the water vapor is 1-40h-1, the molar ratio of the methane to the water vapor is (1-10):1, the superficial gas velocity of the adsorbent passage is 0.05-0.5m / s, and the molar ratio of the methane to the adsorbent in the feed is 1:(1-3). -1

[0034] Optionally, the average particle size of the adsorbent particles is 0.04-0.10mm, and the minimum size of the catalyst particles is 4-50mm.

[0035] Optionally, the adsorbent particles comprise an adsorption active component and an inorganic heat-resistant oxide, and the content of the adsorption active component is 30-85wt% based on the total weight of the adsorbent particles;

[0036] Optionally, the adsorption active component comprises CaO and / or MgO;

[0037] The inorganic heat-resistant oxide comprises Al2O3 and / or SiO2;

[0038] The molar ratio of the adsorption active component to the methane is (1-1.5):1.

[0039] Optionally, the catalyst particles comprise a carrier and a metal active component, and the content of the metal active component is 0.1-25wt% based on the total weight of the catalyst particles, and the content of the metal active component is calculated based on the weight of the oxide; ​

[0040] Optionally, the carrier comprises one or more of nano-alumina, nano-silica and nano-titania.

[0041] The metal active component contains one or more of Ni element, Co element, Fe element, Rh element, Ru element, Pt element, Cr element, Mg element, La element, Ce element, Yb element, Pr element, Nd element, La element, Ce element and Zr element.

[0042] Optionally, the method further comprises: preheating the methane and the steam before entering the gas-solid coupled fluidized bed reactor, and the temperature of the methane and the steam after the preheating is 500-900℃.

[0043] Optionally, the method further comprises: introducing the adsorbent particles and the raw material gas from the bottom of the reactor and flowing from bottom to top through the reaction zone, and performing gas-solid separation on the reaction material obtained from the top of the reaction zone to obtain spent adsorbent and gas product.

[0044] Optionally, the method further comprises: introducing the spent adsorbent into a regenerator for regeneration treatment, and returning the regenerated adsorbent obtained by regeneration to the gas-solid coupled fluidized bed reactor for continuous use.

[0045] Through the above technical solution, the gas-solid coupled fluidized bed for the process of catalytic reforming of methane to produce hydrogen in the present disclosure sets the catalyst particles and the adsorbent particles in the catalytic member and the adsorbent channel in which the solid particles do not flow into each other, and the two do not contact each other, which overcomes the problem of particle loss when the adsorbent particles pass through the catalyst particles, and reduces the probability of adsorbent particle blockage in the catalyst bed. The reaction gas frequently enters and exits the catalytic member and contacts the adsorbent in the adsorbent flow channel, the CO2 and the adsorbent particles react and release heat, which makes up for the strong endothermic requirement of methane reforming to produce hydrogen, strengthens the process reaction, and improves the efficiency of methane reforming to produce hydrogen. The reaction device of the present disclosure has a simple structure and can realize continuous operation with high production efficiency.

[0046] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments section. BRIEF DESCRIPTION OF DRAWINGS

[0047] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and together with the following specific embodiments, serve to explain the present disclosure but do not constitute a limitation thereof. In the drawings:

[0048] Figure 1 is a structural schematic diagram of a gas-solid coupled fluidized bed reactor according to an embodiment of the present disclosure.

[0049] Figure 2 is a magnified view of the catalytic member of an embodiment of the present application.

[0050] Figure 3 is a plan view of a layer of catalytic members of an embodiment of the present application.

[0051] Legend of reference signs

[0052] 1 - feed gas inlet, 2 - lower head, 3 - catalytic member, 4 - adsorbent channel, 5 - reaction zone, 6 - expanded section, 7 - settling zone, 8 - upper head, 9 - gas outlet, 10 - gas-solids separator, 11 - adsorbent outlet, 12 - adsorbent inlet, 13 - gas distributor. DETAILED DESCRIPTION

[0053] The specific embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0054] In the present disclosure, the orientation words such as "upper" and "lower" used herein generally refer to the upper and lower of the device in the normal use state, and can be specifically referred to the surface direction of the drawings in the accompanying drawings. Figure 1 "Inner" and "outer" are relative to the contour of the device itself.

[0055] The first aspect of the present disclosure provides a gas-solid coupled fluidized bed reactor for preparing hydrogen, which comprises a reactor shell, wherein the reactor shell comprises, from bottom to top, a reaction zone, an expanded section and a settling zone.

[0056] The catalytic member is configured to be capable of confining catalyst particles inside the catalytic member, confining adsorbent particles outside the catalytic member, and allowing reaction gas to flow into and out of the catalytic member; an adsorbent channel capable of accommodating the flow of adsorbent particles is formed between the outer wall of the catalytic member and the inner wall of the reaction zone.

[0057] In the present disclosure, catalyst particles are placed in the catalytic members, which play a role similar to a fixed bed, and adsorbent particles flow through the adsorbent channels, which play a role similar to a fluidized bed, thus forming a gas-solid coupled fluidized bed reactor of the present disclosure. The reaction zone is used to provide a reaction site for the hydrogenation reaction. In the reaction zone, the raw gas enters the catalytic members and reacts with the catalysts, and the gas reaction products diffuse out of the catalytic members and contact the adsorbents in the adsorbent flow channels, so that the carbon dioxide in the products is adsorbed by the adsorbents. The expansion section and the settling section are used to separate the reaction material containing the product gas and the spent adsorbent flowing out of the top of the reaction zone, and the separated spent adsorbent can be led out of the reactor for regeneration, and the separated gas products can be led out of the reactor for use or further processing.

[0058] In an embodiment of the present disclosure, a plurality of catalytic member layers are arranged axially in the reaction zone, and each catalytic member layer comprises a plurality of catalytic members arranged in the same layer. Preferably, the shapes and sizes of the plurality of catalytic members are the same. The "layer" of the catalytic member layer refers to a horizontal plane perpendicular to the axial direction of the reactor.

[0059] In an embodiment of the present disclosure, each catalytic member layer is placed on a support beam in the reactor and is fixed by a reinforcing rib. The inside of each catalytic member is arranged to be reinforced by the reinforcing rib to prevent the catalytic member from shaking during the reaction. The outer wall of the catalytic member is arranged to be connected and fixed by a lug. The lug can be connected and fixed to the support beam of the reactor or the adjacent catalytic member by bolts or welding. The support beam is a conventional reactor component.

[0060] In an embodiment of the present disclosure, the number of catalytic member layers is 2-15, preferably 2-10; and the number of catalytic members in each catalytic member layer is 2-100, preferably 2-80.

[0061] In an embodiment of the present disclosure, the distance between adjacent catalytic member layers is 20-400 cm, preferably 100-300 cm; and the distance between radially adjacent catalytic members in the axial cross section is 100-500 cm, preferably 100-300 cm. The "distance between adjacent catalytic member layers" refers to the distance between the vertical axial horizontal cross section of the bottom of any catalytic member layer and the vertical axial horizontal cross section of the top of the adjacent catalytic member layer.

[0062] In an embodiment of the present disclosure, as Figure 3As shown, in each layer of the catalytic member, a space is formed between two adjacent catalytic members to form an adsorbent channel including all the spaces in the layer of the catalytic member. In the reaction zone, the adsorbent flows in the adsorbent channel and does not enter the catalytic member; in a preferred embodiment, the ratio of the cross-sectional area of the adsorbent channel to the cross-sectional area of all the catalytic members in the radial cross-section of each layer of the catalytic member is (1-3): 1, preferably (1-2): 1, to further improve the efficiency of the reaction gas entering and exiting the catalytic member. The cross-sectional area of the adsorbent channel refers to the total area of all the adsorbent channels in the horizontal cross-section, and the cross-sectional area of all the catalytic members refers to the total area of all the catalytic members in the horizontal cross-section.

[0063] In the present disclosure, the adsorbent particles can freely flow in the adsorbent channel and fully contact the gas generated by the reaction, improving the adsorption efficiency of CO2.

[0064] In an embodiment of the present disclosure, the catalytic member is formed as a catalyst cage, and the cage wall of the catalyst cage has apertures configured to prevent the passage of the catalyst particles and the passage of the adsorbent particles. The diameter of the apertures is smaller than the smallest dimension of the catalyst particles and smaller than the smallest dimension of the adsorbent particles. For example, for spherical particles, the smallest dimension is the diameter, and for cylindrical particles, the smallest dimension is the smaller value of the height of the cylinder and the diameter of the base. The catalyst cage satisfying the above conditions avoids direct contact between the catalyst particles and the adsorbent particles, thereby preventing the loss of the adsorbent particles.

[0065] In order to facilitate the loading and unloading of the catalyst particles, in an embodiment of the present disclosure, the upper portion and the bottom portion of the catalyst cage are provided with loading and unloading ports for the catalyst, and the cover plate of the loading and unloading port can satisfy the requirement that the gas can pass through but the catalyst particles and the adsorbent particles cannot pass through, and facilitate disassembly.

[0066] In the present disclosure, as shown, Figure 1 The axial cross-section of the catalyst cage can be an irregular shape, and the edges of the cross-section can be straight lines, arcs, curves, broken lines, etc.; the cross-section can also be a polygon, such as a triangle, a quadrilateral, a pentagon, etc. The axial cross-section refers to the axial cross-section of the short edge in the radial direction of the catalyst cage.

[0067] In the present disclosure, as shown, Figure 1 The axial cross-section of the adsorbent channel can be an irregular shape, and the edges of the cross-section can be straight lines, arcs, curves, broken lines, etc.; the cross-section can also be a polygon, such as a triangle, a quadrilateral, a pentagon, etc.

[0068] In one embodiment of the present disclosure, the cage wall is made of wire mesh, and the wire mesh is made of one or more of stainless steel wire mesh, Johnson wire mesh and metal powder sintered plate with holes. In another embodiment, the cage wall is made of porous plate with holes.

[0069] In a further embodiment, as shown in Figure 2 , the catalyst cage is formed as a flat cage, and has at least one set of main cage walls arranged in parallel, and the wall surface of the main cage wall is arranged at an angle to the layer surface of the catalytic member layer; optionally, the angle a between the wall surface of the main cage wall and the layer surface is 40-85°, preferably 45-75°. The "layer surface" refers to the horizontal surface perpendicular to the axial direction, and the angle a is the angle between the main view surface of the catalytic member in Figure 1 and the horizontal direction. The smaller the angle between the wall surface of the main cage wall and the layer surface, the less conducive to fluidization of the adsorbent, and the larger the angle between the wall surface of the main cage wall and the layer surface, the less conducive to the entry of the reaction gas into the catalyst cage. A suitable angle between the wall surface of the main cage wall and the layer surface is conducive to maintaining the fluidization of the adsorbent and the entry and exit of the reaction gas into and out of the catalyst cage.

[0070] In order to avoid the accumulation of adsorbent particles on the top of the catalytic member, in a preferred embodiment of the present disclosure, as shown in Figure 2 , the top surface of the catalyst cage is arranged at an angle to the layer surface of the catalytic member layer; preferably, the angle between the top surface and the layer surface is 45-85°, preferably 50-75°.

[0071] In one embodiment of the present disclosure, the wall surface of the main cage wall has a porosity of 40-80%, preferably 40-70%, and the porosity refers to the proportion of the area of the holes in the main cage wall to the total area of the main cage wall.

[0072] In one embodiment of the present disclosure, in the same catalytic member layer, all the catalyst cages have the same axial height and cage thickness, and the cage thickness represents the distance between two main cage walls arranged in parallel; preferably, there is a spacing with the same width between any two adjacent catalyst cages. Wherein, as shown in Figure 2 , the "thickness" refers to the distance d between the wall surfaces of two parallel main cage walls, and the "width" refers to the distance l between the wall surfaces of the adjacent main cage walls between two adjacent catalyst cages. Further, the ratio of the spacing to the cage thickness is (1-3):1, preferably (1-2):1, and a suitable ratio is conducive to the free entry and exit of the reaction gas into and out of the catalyst cage and the flow passage of the adsorbent.

[0073] In one embodiment of the present disclosure, the reactor shell is provided with an adsorbent inlet, an inactive adsorbent outlet, a raw gas inlet and a gas outlet; the raw gas inlet is arranged at the bottom of the reactor, and the gas outlet is arranged at the top of the settling zone;

[0074] The adsorbent outlet and the adsorbent inlet are arranged at the upper part and the lower part of the reaction zone respectively, and the catalytic component is arranged between the adsorbent inlet and the adsorbent outlet; the adsorbent inlet is used for introducing the adsorbent particles into the reaction zone, and the adsorbent outlet is used for discharging the deactivated adsorbent particles from the reaction zone.

[0075] The gas-solid separator is arranged in the settling zone, and the gas outlet of the gas-solid separator is communicated with the gas outlet of the reactor; the gas-solid separator is conventional and can meet the requirement of gas-solid separation, for example, can be a cyclone separator.

[0076] In the present disclosure, the relative positions of the adsorbent inlet and the adsorbent outlet can be changed, and reactors with different structures can be formed.

[0077] In an embodiment of the present disclosure, a gas distributor is arranged in the lower part of the reaction zone, which is used for distributing the reaction gas entering the reactor, so that the gas can enter the reactor uniformly.

[0078] The second aspect of the present disclosure provides a system for preparing hydrogen, which comprises the gas-solid coupled fluidized bed reactor of the first aspect of the present disclosure.

[0079] In an embodiment of the present disclosure, the system further comprises a CO2 collecting device and an adsorbent regeneration device.

[0080] The CO2 gas outlet, the deactivated adsorbent inlet and the regenerated adsorbent outlet are arranged on the adsorbent regeneration device.

[0081] The deactivated adsorbent inlet is connected with the adsorbent outlet of the gas-solid coupled fluidized bed reactor, the regenerated adsorbent outlet is connected with the adsorbent inlet, and the CO2 gas outlet is connected with the CO2 collecting device.

[0082] The adsorbent regeneration device is used for regenerating the deactivated adsorbent; the deactivated adsorbent particles are discharged from the reaction zone through the deactivated adsorbent outlet, enter the regeneration device through the deactivated adsorbent inlet, are regenerated, are discharged through the regenerated adsorbent outlet, and are recycled into the reaction zone through the adsorbent inlet.

[0083] In an embodiment of the present disclosure, the system further comprises a separation tank for separating the gas products flowing out with the deactivated adsorbent; the separation tank is provided with a mixture inlet, a gas outlet and a deactivated adsorbent outlet, the mixture inlet is connected with the adsorbent outlet, the gas outlet is connected with the gas outlet of the reactor shell, and the deactivated adsorbent outlet is connected with the deactivated adsorbent inlet of the adsorbent regeneration device.

[0084] In one embodiment of the present disclosure, the temperature of the regeneration treatment is 800-1000°C, preferably 800-900°C. The specific method of the regeneration treatment is that the deactivated adsorbent is introduced into an adsorbent regenerator, and high-temperature gas is introduced to heat, wherein the high-temperature gas is an inert gas, and the heating is performed by a heating furnace. The heating furnace is a conventional heating furnace, and there is no special requirement. The inert gas can be, for example, nitrogen, carbon dioxide, or the like.

[0085] The third aspect of the present disclosure provides a method for preparing hydrogen by reforming methane, which comprises: introducing a raw gas comprising methane and water vapor into the reaction zone of the gas-solid coupled fluidized bed reactor of the first aspect of the present disclosure, and allowing the raw gas to react with the catalyst particles in the catalytic member; and introducing adsorbent particles into the reaction zone.

[0086] In one embodiment of the present disclosure, the reaction temperature of the gas-solid coupled fluidized bed reactor is 500-700°C, preferably 550-650°C; the operating pressure is 0.1-5.0 MPa, preferably 0.2-4.0 MPa; the total space velocity of the methane and the water vapor is 1-40 h -1 , preferably 1-20 h -1 ; the molar ratio of the methane to the water vapor is (1-10):1, preferably (2-8):1; the superficial gas velocity of the adsorbent passage is 0.05-0.5 m / s, preferably 0.1-0.4 m / s, and the molar ratio of the methane to the adsorbent in the feed is 1:(1-3), preferably 1:(1-2). Within the above ranges, the conversion of methane to hydrogen is facilitated, and the yield of hydrogen is improved.

[0087] In one embodiment of the present disclosure, the average particle size of the adsorbent particles is 0.04-0.10 mm, preferably 0.5-0.080 mm, and the average particle size is measured by a laser particle size analyzer.

[0088] In one embodiment of the present disclosure, the minimum size of the catalyst particles is 4-50 mm, preferably 4-30 mm. The minimum size of the catalyst refers to the minimum size that ensures that the catalyst particles do not flow out of the pores of the catalyst cage. For example, when the catalyst particles are spherical, the minimum size is the diameter; for another example, when the catalyst particles are strip-shaped, the minimum size is the shortest distance of the cross section perpendicular to the length direction, or the shortest length in the length direction; for another example, when the catalyst particles are columnar, the minimum size is the diameter of the bottom surface or the minimum value of the column height.

[0089] In one embodiment of the present disclosure, the particle size of the adsorbent particles is 0.04-0.10 mm, preferably 0.5-0.080 mm. The particle size is the volume average particle size, and the testing method is a laser particle size analyzer. The particle size of the adsorbent particles can be routinely selected and can meet the requirements of the present application.

[0090] In a further embodiment, the adsorbent particles comprise an adsorption active component and an inorganic heat-resistant oxide, the content of the adsorption active component is 30-85 wt%, preferably 40-80 wt%, based on the total weight of the adsorbent particles; the molar ratio of the adsorption active component to methane is (1-1.5): 1, preferably (1-1.2): 1.

[0091] In one embodiment of the present disclosure, the adsorption active component comprises CaO and / or MgO, and the inorganic heat-resistant oxide comprises Al2O3 and / or SiO2.

[0092] In the present disclosure, the preparation method of the adsorbent particles is a conventional method in the art, and no special requirements are made herein. For example, kaolin is used as a substrate, aluminum sol is used as a binder, and a certain proportion of active components with carbon dioxide adsorption function is added, and then impregnation and calcination are performed to obtain the adsorbent particles.

[0093] In a further embodiment, the catalyst particles comprise a carrier and a metal active component, the content of the metal active component is 0.1-25 wt%, preferably 2-25 wt%, based on the total weight of the catalyst particles, and the content of the metal active component is calculated as the weight of the oxide.

[0094] In one embodiment of the present disclosure, the carrier comprises one or more of nano-alumina, nano-silica, and nano-titanium oxide.

[0095] In one embodiment of the present disclosure, the metal active component contains one or more of Ni, Co, Fe, Rh, Ru, Pt, Cr, Mg, La, Ce, Yb, Pr, Nd, La, Ce, and Zr. The above metal elements can exist in the form of metal elements in the catalyst particles.

[0096] In the present disclosure, the catalyst particle preparation method is a conventional method in the art, and no special requirements are made herein. For example, a certain amount of alumina carrier can be added into a certain amount of alumina hydrosol, a small amount of water is added and stirred uniformly, then a soluble metal salt is added and mixed uniformly for extrusion molding, and then drying is performed. The dried solid material is calcined to obtain catalyst particles. The shape of the catalyst particles can be, for example, a strip, a sphere, a honeycomb or a clover, wherein the soluble metal salt contains one or more of Ni, Co, Fe, Rh, Ru, Pt, Cr, Mg, La, Ce, Yb, Pr, Nd, La, Ce and Zr elements.

[0097] In an embodiment of the present disclosure, the method further comprises: preheating the methane and water vapor before entering the gas-solid coupled fluidized bed reactor. After preheating, the temperature of the methane and water vapor is 500-900°C, preferably 550-850°C. The preheating method can be, for example, at least one stage of preheating.

[0098] In an embodiment of the present disclosure, the method further comprises: introducing the adsorbent particles and the raw material gas from the bottom of the reactor and flowing from bottom to top through the reaction zone, and performing gas-solid separation on the reaction material obtained from the top of the reaction zone to obtain the spent adsorbent and the gas product.

[0099] In order to realize continuous operation and improve reaction efficiency, in a further embodiment, the method further comprises: introducing the spent adsorbent into the regenerator for regeneration treatment, and returning the regenerated adsorbent obtained by regeneration to the gas-solid coupled fluidized bed reactor for continuous use.

[0100] In a specific embodiment of the present disclosure, as Figure 1As shown, the gas-solid coupled fluidized bed reactor is a vertical closed vessel. The reactor shell includes, from bottom to top, a reaction zone 5, a diameter expansion section 6 and a settling zone 7. The upper end of the reactor shell is an upper head 8, and a gas outlet 9 is provided on the upper head 8. The lower end of the reactor shell is a lower head 2, and a raw gas inlet 1 is provided on the lower head 2. The mixture of preheated methane and steam enters the gas-solid coupled fluidized bed reactor through the raw gas inlet 1, enters the lower region of the reaction zone 5 under the action of the gas distributor 13, mixes with the adsorbent particles entering the reactor, and then enters the reaction zone 5. The raw gas enters the catalytic member 3 and reacts with the catalyst particles to generate H2. The generated CO2 flows out of the catalytic member through the pores and is adsorbed by the adsorbent particles in the adsorbent channel. The reacted gas passes through the reaction zone and enters the settling zone 7, is separated by the gas-solid separator 10, and then flows out of the reactor through the gas outlet 9 for subsequent gas separation to obtain the target product H2. The separated solid particles are adsorbent particles that return to the upper bed layer of the reactor. As the reaction proceeds, the deactivated adsorbent particles are discharged from the reactor through the adsorbent outlet 11, separated by a separation tank, and then enter the regenerator for regeneration treatment. The regenerated adsorbent returns to the reactor through the adsorbent inlet 12 for continuous use.

[0101] The method for preparing hydrogen by methane reforming according to the present application is illustrated by the following examples and comparative examples.

[0102] The reagents used in the examples and comparative examples are commercially available unless otherwise specified.

[0103] Example 1

[0104] Preparation of catalyst particles: A certain amount of alumina carrier was added to an alumina hydrosol with a solid content of 10%, a small amount of water was added and stirred uniformly, and then nickel nitrate was added, mixed uniformly, and extruded into a clover shape. The dried catalyst was calcined at 500°C for 4 hours to obtain catalyst particles. The content of the metal active component was 10% by weight based on the total weight of the catalyst particles, and the size of the catalyst particles was φ10mm×6mm.

[0105] Preparation of adsorbent particles: A certain amount of nano-sized calcium carbonate was added to an alumina hydrosol with a solid content of 10%, a small amount of water was added and stirred uniformly, and then nano-sized calcium carbonate and an alumina matrix were added, mixed uniformly, and spray dried and calcined to obtain adsorbent particles with an average particle size of 70mm. The content of CaO was 50% by weight based on the total weight of the adsorbent particles.

[0106] The method for preparing hydrogen by methane reforming according to the present application is illustrated by the following examples and comparative examples. Figure 1The illustrated gas-solid coupled fluidized bed reactor is used for catalytic reforming of methane to produce hydrogen. The reaction zone is provided with five layers of catalytic members, each layer of catalytic members is provided with 20 catalytic members, the distance between adjacent catalytic member layers is 20 cm, and the distance between radially adjacent catalytic members in an axial cross section is 100 cm. The upper part of the reaction zone is provided with an adsorbent inlet, and the lower part is provided with an adsorbent outlet. The catalytic member is a flat catalyst cage, the cage wall is composed of wire mesh (material is Johnson mesh), the horizontal cross section of the catalytic member is quadrilateral, the included angle α between the main cage wall and the layer surface is 60°, the opening rate of the main cage wall is 58%, two groups of main cage walls are arranged in parallel, and the ratio of the cross-sectional area of the adsorbent flow channel to the cross-sectional area of the catalytic member is 1.5:1. In the same layer of catalytic members, all the catalyst cages have the same axial height and cage thickness, and there is a same width interval between any two adjacent catalyst cages.

[0107] After the catalyst loaded in the reactor is reduced, the preheated steam and methane mixture is introduced into the reactor, and the temperature of the methane and steam is 650°C. The total volume flow rate of the raw material gas is 2 m 3 / h per hour, the reaction temperature is controlled at 600°C, the operating pressure is 1 MPa, the molar ratio of steam to methane is 4:1, the total space velocity of steam and methane is 4 h -1 , and the molar ratio of the active component of the adsorbent to methane is 1.5:1. The superficial gas velocity of the adsorbent channel is controlled at 0.3 m / s. The deactivated adsorbent particles in the reactor are introduced into the regenerator for regeneration, and the regeneration temperature is 900°C. The regenerated adsorbent particles are returned to the reaction zone for recycling. After the reaction is carried out for 6 hours, sampling and analysis are performed, and the gas composition after removing water from the gaseous product is shown in Table 1.

[0108] Example 2

[0109] Preparation of catalyst particles: The catalyst particles are prepared by the method of Example 1, except that the content of the metal active component is 25% by weight based on the total weight of the catalyst particles.

[0110] Preparation of adsorbent particles: The catalyst particles are prepared by the method of Example 1, except that the average particle size of the adsorbent particles is 50 mm, and the content of CaO is 80% by weight based on the total weight of the adsorbent particles.

[0111] The hydrogen production by catalytic reforming of methane was carried out by the method of Example 1, except that the angle a between the wall surface and the layer surface of the main cage was 60°, and the ratio of the cross-sectional area of the adsorbent flow channel to the cross-sectional area of the catalytic member was 1.5:1. The reaction temperature was 550°C, the operating pressure was 0.5 MPa, the molar ratio of water vapor to methane was 2:1, the superficial gas velocity of the adsorbent channel was controlled to be 0.5 m / s, and the regeneration temperature of the adsorbent particles was 800°C. Sampling analysis was performed after the reaction was carried out for 6 h, and the gas composition of the gaseous product after removal of water is shown in Table 1.

[0112] Example 3

[0113] Preparation of the catalyst particles: The catalyst particles were prepared by the method of Example 1, except that the content of the metal active component was 5% by weight, based on the total weight of the catalyst particles.

[0114] Preparation of the adsorbent particles: The catalyst particles were prepared by the method of Example 1, except that the average particle size of the adsorbent particles was 80 mm, and the content of CaO was 40% by weight, based on the total weight of the adsorbent particles.

[0115] The hydrogen production by catalytic reforming of methane was carried out by the method of Example 1, except that the angle a between the wall surface and the layer surface of the main cage was 75°, and the ratio of the cross-sectional area of the adsorbent flow channel to the cross-sectional area of the catalytic member was 2:1. The total volume flow rate of the feed gas was 1 m 3 / h per hour, the reaction temperature was 650°C, the operating pressure was 4 MPa, the molar ratio of water vapor to methane was 8:1, the superficial gas velocity of the adsorbent channel was controlled to be 0.1 m / s, and the regeneration temperature of the adsorbent particles was 850°C. Sampling analysis was performed after the reaction was carried out for 6 h, and the gas composition of the gaseous product after removal of water is shown in Table 1.

[0116] Example 4

[0117] The hydrogen production by catalytic reforming of methane was carried out by the method of Example 1, except that the angle a between the wall surface and the layer surface of the main cage was 35°.

[0118] Comparative Example 1

[0119] The hydrogen production method used is described in Chinese Patent CN101559924A. The hydrogen production by catalytic reforming of methane was carried out by using a fluidized reactor, and the catalyst was a fixed bed catalyst, and the adsorbent was a CO2 adsorbent.

[0120] Preparation of the catalyst particles: The catalyst particles of Example 1 were used.

[0121] Preparation of the adsorbent particles: The catalyst particles were prepared by the method of Example 1, except that the average particle size of the adsorbent particles was 30 mm, and the content of CaO was 50% by weight, based on the total weight of the adsorbent particles.

[0122] After the catalyst particles loaded in the reactor are reduced, the preheated water vapor and methane mixture is mixed into the mixer and mixed with the adsorbent particles, and the mixed gas-solid mixture enters the reactor, and the temperature of the methane and water vapor is 650℃. The volume fraction of the adsorbent particles in the material entering the reactor is controlled to be 5%, the total volume flow rate of the raw material gas per hour is 2m 3 / h, the molar ratio of water vapor to methane is 4:1, the reaction temperature is 650℃, the operating pressure is 1Mpa, the adsorbent particles flowing out of the reactor are regenerated in the regenerator, and the regeneration temperature is 900℃. After the reaction is carried out for 6h, sampling analysis is carried out, and the gas composition of the gas product after removing water is shown in Table 1.

[0123] Table 1

[0124]

[0125]

[0126] According to the data in Table 1, the gas-solid coupled fluidized bed reactor provided by the present application can effectively increase the hydrogen content in the product, reduce the content of carbon monoxide and carbon dioxide, and has high production efficiency when the wall surface and the layer surface of the main cage wall form an angle α in the range of 40-85°, and the hydrogen content is higher.

[0127] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0128] In addition, it should be noted that various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0129] In addition, various different embodiments of the present disclosure can also be combined in any appropriate manner, as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A gas-solid coupled fluidized bed reactor for hydrogen production, characterized in that, The gas-solid coupled fluidized bed reactor includes a reactor shell, and the reactor shell includes, from bottom to top, a reaction zone, an expansion section and a settling zone; A catalytic component is provided within the reaction zone. The catalytic component is configured to confine catalyst particles inside the catalytic component, confine adsorbent particles outside the catalytic component, and allow reaction gases to flow into and out of the catalytic component. An adsorbent channel is formed between the outer wall of the catalytic component and the inner wall of the reaction zone to accommodate the flow of adsorbent particles. The reaction zone is provided with multiple catalytic component layers spaced apart along the axial direction, and each catalytic component layer includes multiple catalytic components disposed in the same layer. Within each of the catalytic member layers, a spacer is formed between two adjacent catalytic members to form an adsorbent channel including all of the spacers within the catalytic member layer; The catalytic component is formed as a catalyst cage, the cage wall of which has pores, the pore structure being designed to prevent catalyst particles from passing through and adsorbent particles from passing through. The catalyst cage is formed as a flat cage and has at least one set of main cage walls arranged in parallel with each other. The wall surface of the main cage wall is angled to the surface of the catalyst component layer. The angle α between the wall surface of the main cage wall and the layer is 40-85°.

2. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, The multiple catalytic components are identical in shape and size.

3. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, The number of catalyst component layers is 2-15, and the number of catalyst components in each catalyst component layer is 2-100.

4. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, The distance between adjacent catalyst component layers is 20-400cm; the distance between radially adjacent catalyst components in the axial section is 100-500cm.

5. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, On the radial cross-section of each of the catalytic element layers, the ratio of the cross-sectional area of ​​the adsorbent channel to the cross-sectional area of ​​all the catalytic elements is (1-3):

1.

6. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, The cage wall is made of wire mesh, which is one or more of the following materials: stainless steel wire mesh, Johnson wire mesh, and perforated metal powder sintered plate.

7. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, The main cage wall has a wall perforation rate of 40-80%.

8. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, Within the same catalyst element layer, all the catalyst cages have the same axial height and cage thickness, where the cage thickness represents the distance between two relatively parallel main cage walls; any two adjacent catalyst cages have a gap of the same width between them.

9. The gas-solid coupled fluidized bed reactor according to claim 1, wherein, The reactor shell is provided with an adsorbent inlet, an adsorbent outlet, a raw material gas inlet, and a gas outlet; the raw material gas inlet is located at the bottom of the reactor, and the gas outlet is located at the top of the settling zone; The adsorbent outlet and adsorbent inlet are respectively located at the upper and lower parts of the reaction zone, and the catalytic component is located between the adsorbent inlet and the deactivated adsorbent outlet; A gas-solid separator is provided in the settling zone, and the gas outlet of the gas-solid separator is connected to the gas outlet of the reactor.

10. A system for producing hydrogen, characterized in that, The system includes the gas-solid coupled fluidized bed reactor as described in any one of claims 1-9.

11. The system according to claim 10, wherein, The system also includes a CO2 collection device and an adsorbent regeneration device; The adsorbent regeneration device is equipped with a CO2 gas outlet, a deactivated adsorbent inlet, and a regenerated adsorbent outlet. The deactivated adsorbent inlet is connected to the adsorbent outlet of the gas-solid coupled fluidized bed reactor, the regenerated adsorbent outlet is connected to the adsorbent inlet, and the CO2 gas outlet is connected to the CO2 collection device. The adsorbent regeneration device is used to regenerate deactivated adsorbents.

12. The system according to claim 10, wherein, The temperature for the regeneration process is 800-1000℃.

13. A method for preparing hydrogen by methane reforming, characterized in that, The method includes: introducing a feed gas containing methane and water vapor into the reaction zone of the gas-solid coupled fluidized bed reactor according to any one of claims 1-9, and reacting it with the catalyst particles in the catalytic member; and introducing adsorbent particles into the reaction zone.

14. The method according to claim 13, wherein, The gas-solid coupled fluidized bed reactor operates at a temperature of 500-700℃ and a pressure of 0.1-5.0 MPa, with a total space velocity (SHSV) of 1-40 h⁻¹ for both methane and water vapor. -1 The molar ratio of methane to water vapor is (1-10):1, the apparent gas velocity of the adsorbent channel is 0.05-0.5 m / s, and the feed molar ratio of methane to adsorbent is 1:(1-3).

15. The method according to claim 13, wherein, The average particle size of the adsorbent particles is 0.04-0.10 mm, and the minimum size of the catalyst particles is 4-50 mm.

16. The method according to claim 13, wherein, The adsorbent particles comprise an adsorption active component and an inorganic heat-resistant oxide. Based on the total weight of the adsorbent particles, the content of the adsorption active component is 30-85% by weight. The molar ratio of the adsorption active component to the methane is (1-1.5):

1.

17. The method according to claim 16, wherein, The adsorption active component includes CaO and / or MgO; the inorganic heat-resistant oxide includes Al2O3 and / or SiO2.

18. The method according to claim 13, wherein, The catalyst particles include a support and a metal active component. Based on the total weight of the catalyst particles, the content of the metal active component is 0.1-25% by weight, and the content of the metal active component is based on the weight of the oxide. The active metal component contains one or more of the following elements: Ni, Co, Fe, Rh, Ru, Pt, Cr, Mg, La, Ce, Yb, Pr, Nd, La, Ce, and Zr.

19. The method according to claim 18, wherein, The carrier includes one or more of nano-alumina, nano-silicon oxide, and nano-titanium oxide.

20. The method according to claim 13, wherein, The method further includes: preheating the methane and water vapor before they enter the gas-solid coupled fluidized bed reactor, wherein the temperature of the methane and water vapor after the preheating treatment is 500-900°C.

21. The method according to claim 13, wherein, The method further includes: introducing the adsorbent particles and the raw gas from the bottom of the reactor and flowing them from bottom to top through the reaction zone; performing gas-solid separation on the reactants obtained from the top of the reaction zone to obtain the adsorbent to be produced and the gaseous product.

22. The method according to claim 21, wherein, The method further includes: introducing the adsorbent to be regenerated into a regenerator for regeneration, and returning the regenerated adsorbent to the gas-solid coupled fluidized bed reactor for continued use.

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