Chemical looping hydrogen production reactor based on rotational flow bed

Abstract

The invention discloses a chemical-looping hydrogen production reactor based on a rotational flow bed. The chemical-looping hydrogen production reactor comprises a reactor barrel, an air distribution plate is arranged in the reactor barrel and divides the reactor barrel into an air inlet area and a reaction area in the axial direction, a center body coaxial with the reactor and a baffle arranged in the radial direction of the reactor are arranged in the reaction area, and the area between the reaction area and the center body is an effective fluidization area of the reactor. The baffle divides the effective fluidization area into a reduction area and an oxidation area; a circulating channel is arranged on one side, close to the air distribution plate, of the baffle; wherein the air distribution plate consists of a plurality of fan-shaped blades, the plurality of fan-shaped blades are spirally wound on the central body by taking the central body as a shaft, and a gap for air flow to pass through is formed between every two adjacent fan-shaped blades; and the included angle between the fan-shaped blades and the radial section of the reactor is 30-75 degrees, so that the oxygen carrier particles repeatedly flow between the reduction area and the oxidation area under the driving of rotational flow rising reaction gas to carry out circular reaction.

Description

Technical Field

[0001] This invention relates to a chemical looping reactor, and more particularly to a chemical looping hydrogen production reactor based on a cyclone bed. Background Technology

[0002] Chemical looping technology is a clean energy conversion technology that decouples the reaction process in time and space by carrying out redox reactions in steps in different regions. This technology typically utilizes an oxygen carrier circulating between the reduction reactor and the oxidation reactor to achieve the transfer of lattice oxygen and heat, and is widely used in processes such as hydrogen production, combustion, and gasification.

[0003] To achieve spatial partitioning of the oxidation and reduction processes of oxygen carriers, existing technologies commonly employ dual fluidized bed structures. In such devices, oxygen-carrying particles are transported to a high position via a riser pipe using high-pressure gas, and then continuously circulate through different functional zones under gravity and gas drag. Although this structure achieves functional partitioning, its large particle circulation height and long path heavily rely on the pneumatic conveying system, placing new demands on the power of the blower and electricity consumption. Furthermore, the high gas velocity during pneumatic conveying results in dilute phase contact within the riser pipe, leading to a decrease in reaction rate and fuel utilization. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a chemical looping hydrogen production reactor based on a cyclone bed. This chemical looping hydrogen production reactor can effectively improve the reaction rate of each reaction zone by using a specific structure of the air distribution plate combined with the regulation of the inlet air velocity in different reaction zones, thereby improving the hydrogen production efficiency of the chemical looping reactor.

[0005] Technical Solution: The chemical looping hydrogen production reactor based on a swirl bed of the present invention includes a reactor cylinder; the reactor cylinder is provided with an air distribution plate, which divides the reactor cylinder into an inlet zone and a reaction zone along the axial direction. Within the reaction zone, a central body coaxially arranged with the reactor and baffles arranged radially along the reactor are provided. The area between the reaction zone and the central body is the effective fluidization zone of the reactor. The baffles divide the effective fluidization zone into a reduction zone and an oxidation zone. A circulation channel is provided on the side of the baffles near the air distribution plate. The air distribution plate is composed of multiple fan-shaped blades, which spirally surround the central body with the central body as the axis. The other end of the blades is fixed to the inner wall of the reactor cylinder, and there are gaps between adjacent fan-shaped blades for airflow to pass through. The angle between the fan-shaped blades and the radial profile of the reactor is 30-75°, causing the gas in the inlet zone to enter the effective fluidization zone in a swirling manner, thereby driving the oxygen-carrying particles in the effective fluidization zone to repeatedly flow between the reduction and oxidation zones for a circulating reaction.

[0006] The air distribution plate is covered with wire mesh, and the mesh size of the wire mesh is not larger than the particle size of the oxygen carrier particles.

[0007] The height of the circulation channel is 10% to 20% of the total height of the baffle. During operation, under the influence of gravity and local flow field, particles naturally accumulate in this area, forming a slow particle flow state, which can effectively prevent the penetration or crossflow of gases from different reaction zones.

[0008] The reactor cylinder has gasification gas outlet and high-purity hydrogen outlet in the corresponding reduction zone and oxidation zone, respectively.

[0009] The air intake area is provided with a partition plate that is on the same plane as the baffle. The partition plate divides the air intake area into two independent areas. The two areas are connected to the reduction area and the oxidation area respectively through the air distribution plate. The air intake area has a reduction area air inlet on the side corresponding to the reduction area and an oxidation area air inlet on the side corresponding to the oxidation area.

[0010] Each blade is fan-shaped; the angle between each blade and the radial section of the reactor is 30–75°, thus guiding the gas in the inlet zone into the fluidized bed in a swirling upward manner, achieving rotational drive of the oxygen carrier particles. The height of the connection point between each blade and the inner wall of the reactor cylinder is higher than the height of the connection point between the blade and the outer wall of the central part of the reactor.

[0011] This invention features a 28-blade air distribution plate, arranged in a two-sparse, five-dense configuration based on the gap size between blades. Due to the unified air intake zone and the inherent thickness of the blades, under the same intake pressure, the sparsely arranged areas exhibit lower channel resistance and higher air velocity, while the densely arranged areas have higher channel resistance and lower air velocity. This results in a non-uniform air velocity distribution along the circumference of the reactor shell, which is beneficial for creating a turbulent flow field, promoting particle mixing and uniform heat distribution, and improving reaction efficiency. For the oxidation zone, the blades are arranged circumferentially as follows: densely arranged blades directly below the inlet circulation channel to suppress gas short-circuiting; sparsely arranged blades adjacent to the inlet circulation channel to promote particle circulation; alternating dense and sparse blades in the middle region to create a turbulent flow field; and densely arranged blades near the outlet circulation channel, with the densely arranged area directly below the outlet circulation channel. For the reduction zone, the arrangement of the blades along the circumference of the reactor shell is similar to that of the oxidation zone: they are densely arranged directly below the inlet circulation channel, then sparsely arranged near the inlet circulation channel, with alternating dense and sparse arrangements in the middle, and densely arranged near the outlet circulation channel, with the area directly below the outlet circulation channel being the densely arranged area.

[0012] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: The chemical looping hydrogen production reactor of this invention can effectively reduce the high energy loss and low reaction rate caused by pneumatic transport in the traditional longitudinal circulating dual fluidized bed chemical looping hydrogen production process. On the one hand, this invention utilizes a specially structured air distribution plate to simultaneously form horizontal functional zones through baffles. The specially structured air distribution plate gives the fluidizing gas a tangential velocity component, thereby driving the fluidized bed to rotate and flow, realizing horizontal cross-zone circulation of the oxygen carrier in the dense phase zone. While enhancing the turbulence and gas-solid mixing effect inside the bed, the oxygen carrier particles do not need to be lifted, thus effectively reducing the fluidizing air energy consumption required for oxygen carrier particle circulation. On the other hand, this invention utilizes a specially structured air distribution plate combined with the control of the inlet air velocity in different reaction zones to form high-speed and low-speed zones for oxygen carrier particle movement along the circumference of the reactor in each reaction zone, thereby accelerating the mixing and heat and mass transfer processes of high and low temperature oxygen carrier particles, achieving faster reaction efficiency while extending the residence time of oxygen carrier particles in the corresponding reaction zone, ensuring complete reaction, and thus improving the hydrogen production efficiency of the reactor. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the chemical loop hydrogen production reactor of the present invention.

[0014] Figure 2 A partial view showing the connection between a single blade and the central body, as well as its connection to the inner wall of the cylinder.

[0015] Figure 3 This diagram shows the arrangement of the blades along the circumference of the reactor in the oxidation zone.

[0016] Figure 4 This diagram shows the arrangement of the blades along the circumference of the reactor in the reduction zone. Detailed Implementation

[0017] like Figures 1-4As shown, the present invention relates to a chemical looping hydrogen production reactor based on a cyclone bed, comprising a reactor cylinder 1; an air distribution plate 2 is provided inside the reactor cylinder 1, which divides the reactor cylinder 1 axially into an inlet zone 10 and a reaction zone; a central body 3 coaxially arranged with the reactor and a baffle 4 arranged radially with the reactor are provided in the reaction zone; the area between the reaction zone and the central body 3 is the effective fluidization zone of the reactor; the central body 3 is a cylinder located at the center of the reactor, and its height covers the entire effective fluidization zone of the bed; the baffle 4 divides the effective fluidization zone into a reduction zone 5 and an oxidation zone 6; a circulation channel 9 is provided on the side of the baffle 4 near the air distribution plate 2, the circulation channel 9 is used for the lateral flow and spontaneous circulation of oxygen carrier particles, and the height of the circulation channel 9 is 10 times the height of the baffle 4. % to 20%, during operation, the oxygen carrier particles are affected by gravity and local flow field, and the oxygen carrier particles will naturally accumulate in this area, forming a slow flow state of oxygen carrier particles (this state is called a material seal structure to prevent gas short circuit), which can effectively prevent the penetration or crossflow of gases from different reaction zones; among them, the air distribution plate 2 is composed of multiple fan-shaped blades, which are spirally wrapped around the central body 3 with the central body 3 as the axis, and the other end of the blades is fixed to the inner wall of the reactor cylinder 1. There are gaps between adjacent fan-shaped blades for airflow to pass through; the angle between the fan-shaped blades and the radial section of the reactor is 30 to 75°, so that the oxygen carrier particles are repeatedly flowed between the reduction zone 5 and the oxidation zone 6 under the drive of the swirling reaction gas to carry out the cyclic reaction.

[0018] A wire mesh 14 is laid on the air distribution plate 2, and the mesh size of the wire mesh 14 is not larger than the particle size of the oxygen carrier particles.

[0019] The reactor cylinder 1 has a gasified gas outlet 7 and a high-purity hydrogen outlet 8 on the corresponding reduction zone 5 and oxidation zone 6, respectively. The inlet zone 10 is equipped with a baffle 13 that is on the same plane as the baffle. The baffle 13 divides the inlet zone 10 into two independent areas. The two areas are connected to the reduction zone 5 and the oxidation zone 6 through the air distribution plate, respectively. The inlet zone 10 has a reduction zone inlet 11 on the side corresponding to the reduction zone 5 and an oxidation zone inlet 12 on the side corresponding to the oxidation zone 6. During operation, gas is introduced through the reduction zone inlet 11 and the oxidation zone inlet 12, respectively. The gas enters the reaction zone in a spiral tangential form through the air distribution plate 2.

[0020] Each blade is fan-shaped; the angle between each blade and the radial section of the reactor is 30–75°, thus guiding the gas in the inlet zone into the fluidized bed in a swirling upward manner, achieving rotational drive of the oxygen carrier particles. Simultaneously, the height of the connection point between each blade and the inner wall of the reactor cylinder is higher than the height of the connection point between the blade and the outer wall of the central outer ring. This inclined arrangement promotes the flow of particles from the inner wall (outer ring) of the cylinder to the outer wall (inner ring) of the central outer ring within the reaction zone, promoting particle mixing radially within the reactor and maintaining a radial temperature difference of 5–10°C for the oxygen carrier particles within the reaction zone.

[0021] The air distribution plate 2 of this invention has a total of 28 blades, which are arranged in a two-sparse and five-dense pattern based on the size of the gap between two blades. Since the air is uniformly supplied by the corresponding air inlet zone and the blades themselves have a certain thickness, under the same air inlet pressure, the area with sparsely arranged blades has low channel resistance and high air velocity; the area with densely arranged blades has high channel resistance and low air velocity. This forms a non-uniform air velocity distribution around the reactor cylinder, which is beneficial for building a turbulent flow field, promoting particle mixing and uniform heat distribution, and improving reaction efficiency. For the oxidation zone 6, along the circumference of the reactor cylinder 1, the blades are arranged as follows: the blades are densely arranged directly below the inlet circulation channel to suppress gas short-circuiting; the blades adjacent to the inlet circulation channel are sparsely arranged to promote particle circulation; the blades in the middle area are arranged alternately with dense and sparse blades to build a turbulent flow field; and the blades are densely arranged near the outlet circulation channel, with the area directly below the outlet circulation channel being the densely arranged blade area. For reduction zone 5, the blade arrangement along the circumference of reactor cylinder 1 is similar to that of oxidation zone: densely arranged blades directly below the inlet circulation channel, sparsely arranged blades immediately following the inlet circulation channel, alternating dense and sparse blade arrangements in the middle region, and densely arranged blades near the outlet circulation channel, with the densely arranged blade area directly below the outlet circulation channel. This invention, through this arrangement of air distribution plate blades, creates high-speed and low-speed zones for the movement of oxygen-carrying particles along the circumference of the reactor in both reduction and oxidation zones, thereby accelerating the mixing and heat and mass transfer processes of high and low temperature oxygen-carrying particles along the circumference and improving the reactor's hydrogen production efficiency.

[0022] During the operation of the reactor of this invention, the oxygen carrier particles undergo a reduction reaction with fuel gas (such as CH4, CO, H2) in the reduction zone 5 during circulation, releasing lattice oxygen and generating CO2 and H2O. Simultaneously, the oxygen carrier is converted from MeO2... x Transform into MeO x-1 The deactivated oxygen carrier flows into the oxidation zone 6 through the circulation channel 9 under the influence of the swirling reaction gas, where it is partially re-oxidized to MeO by water vapor. x At the same time, H2 is generated, thus achieving a complete closed loop.

[0023] Example 1

[0024] The chemical looping hydrogen production method based on the above-mentioned chemical looping hydrogen production reactor specifically involves: adding 4 kg of MAC iron ore oxygen carrier particles into the reactor; introducing biomass gasification gas (containing CO, CH4, and N2) into the inlet of the reduction zone at a flow rate of 0.5 m³ / min. 3 The oxygen carrier enters the reduction zone through the air distribution plate and reacts with the oxygen carrier particles at 850°C to generate a reduced oxygen carrier. The reduced oxygen carrier then enters the oxidation zone through the circulation port. At the same time, 0.6 kg / h of water vapor is introduced into the oxidation zone. The water vapor reacts with the reduced oxygen carrier at 850°C to generate high-purity hydrogen. The reduced oxygen carrier is simultaneously oxidized, completing its regeneration, and then re-enters the reduction zone.

[0025] During the hot-state experiment, high-purity nitrogen was used to supplement the fluidizing air, reaching a gas velocity of 2.2 m / s in the high-speed zone and 1.2 m / s in the low-speed zone at the blade air distributor. The hydrogen production in Example 1 reached 0.25 m³ / s. 3 / h, hydrogen production rate is 0.5m 3 / m 3 Gasification.

[0026] At the same scale, compared to traditional longitudinal circulating dual fluidized bed chemical looping hydrogen production, the hydrogen production efficiency can be improved by nearly 20%. With the same size oxygen carrier particles, the fluidizing air velocity required for stable fluidization in a traditional fluidized bed riser is about 7 m / s, while the reactor used in Example 1 uses lateral circulation driven by tangential airflow, which effectively reduces the required fluidizing air and the overall energy consumption per unit of hydrogen production is expected to decrease by about 22%.

[0027] Comparative Example 1

[0028] The only difference between Comparative Example 1 and Example 1 is that the air distribution plates in Comparative Example 1 are uniformly distributed, meaning the gaps between the blades are of the same size without any distinction between high-speed and low-speed zones. Under the same airflow, the apparent wind speed is 1.64 m / s, and the hydrogen production of Comparative Example 1 is 0.19 m³ / s. 3 / h.

Claims

1. A chemical looping hydrogen production reactor based on a cyclone bed, comprising a reactor shell (1); characterized in that: The reactor cylinder (1) is provided with an air distribution plate (2), which divides the reactor cylinder (1) into an air inlet zone (10) and a reaction zone along the axial direction. In the reaction zone, a central body (3) is arranged coaxially with the reactor and a baffle (4) is arranged radially along the reactor. The area between the reaction zone and the central body (3) is the effective fluidization zone of the reactor. The baffle (4) divides the effective fluidization zone into a reduction zone (5) and an oxidation zone (6). The baffle (4) is provided with a circulation channel (9) on the side close to the air distribution plate (2). The air distribution plate (2) is composed of multiple fan-shaped blades. The multiple fan-shaped blades are spirally wrapped around the central body (3) with the central body (3) as the axis. There is a gap between adjacent fan-shaped blades for airflow to pass through. The angle between the blades and the radial section of the reactor is 30 to 75°, so that the oxygen carrier particles are repeatedly flowed between the reduction zone (5) and the oxidation zone (6) under the drive of the swirling reaction gas.

2. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: The air distribution plate (2) is covered with wire mesh (14), and the mesh size of the wire mesh (14) is not larger than the particle size of the oxygen carrier particles.

3. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: The height of the circulation channel (9) is 10% to 20% of the height of the baffle (4).

4. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 3, characterized in that: At the circulation channel (9), low-flow-rate oxygen carrier particles form a sealing structure to prevent gas short circuits.

5. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: The reactor cylinder (1) has gasification gas outlet (7) and hydrogen outlet (8) respectively on the corresponding reduction zone (5) and oxidation zone (6).

6. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: The air intake area (10) is provided with a partition (13) that is coplanar with the baffle. The partition (13) divides the air intake area (10) into two independent areas. The two areas are connected to the reduction area (5) and the oxidation area (6) respectively via the air distribution plate. The air intake area (10) is provided with a reduction area air inlet (11) on the side corresponding to the reduction area (5) and an oxidation area air inlet (12) on the side corresponding to the oxidation area (6).

7. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: The height of the connection point between each fan-shaped blade and the inner wall of the reactor cylinder (1) is higher than the height of the connection point between each fan-shaped blade and the outer wall of the central body (3).

8. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: The amount of oxygen carrier particles in the reactor is 20-40% of the effective fluidized zone volume.

9. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: For the oxidation zone (6), along the circumference of the reactor cylinder (1), the arrangement of the blades of the air distribution plate (2) is as follows: the blades are densely arranged in the circulation channel, sparsely arranged near the circulation channel, and the blades in the middle area of ​​the oxidation zone are arranged in a mixed pattern of dense and sparse.

10. The chemical looping hydrogen production reactor based on a cyclone bed according to claim 1, characterized in that: For the reduction zone (5), along the circumference of the reactor cylinder (1), the arrangement of the blades of the air distribution plate (2) is as follows: the blades are densely arranged at the circulation channel, sparsely arranged near the circulation channel, and the blades in the middle area of ​​the reduction zone are arranged in a mixed pattern of dense and sparse.

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