CN1238105C - Quick-speed fluidized bed reactor capable of realizing particles and gas back flow contact - Google Patents

Abstract

The invention discloses a fast fluidized bed reactor capable of realizing countercurrent contact between particles and gas, belonging to the field of chemical reaction devices. The orifice plate with regular holes is placed in the reactor at a certain angle to the horizontal line in a zigzag shape or horizontally layered. The particles enter the reactor from the particle inlet in the upper part of the reactor, and the gas enters the reactor from the lower part of the reactor. The gas inlet enters the reactor. The particles move downward in a stacked state on the orifice plate, and the gas moves upward through the dense phase layer of the particles. At the same time, the structure of the hole and the orifice plate is matched to ensure good contact between the gas-solid two-phase and realize countercurrent contact. It overcomes the shortcomings of the particles in the prior art that they are highly followable to the gas movement, and can still provide a high driving force for mass transfer and heat transfer in the later stage of the reaction. The invention can be applied to various reactors such as catalytic cracking regenerators.

Description

Fast Fluidized Bed Reactor for Particle-Gas Countercurrent Contact

technical field

The invention belongs to the field of chemical reaction devices, in particular to a fast fluidized bed reactor capable of realizing countercurrent contact between particles and gas.

Background technique

Common gas and solid reactor forms include fixed bed, moving bed, and fluidized bed. The particles used in fixed and moving beds are usually larger than 1 mm in size. The particles used in the fluidized bed are relatively small, ranging in size from 10-1000 microns. The internal diffusion resistance of small particle size particles is greatly reduced, making the fluidized bed suitable for rapid reaction processes such as coal combustion and fluid catalytic cracking. In addition, the smaller particles allow them to be carried out by the gas, which is also advantageous for powder handling and catalytic reactions for rapid deactivation. However, when the particle size becomes smaller, the particle's ability to follow the gas movement is greatly enhanced. Therefore, in the existing fast fluidized bed reactor, the particles and the gas can only move in parallel in the same direction, and it is impossible to provide a relatively fast fluidized bed reactor in the later stage of the reaction. High mass transfer and heat transfer efficiency are unfavorable for pollutant treatment and catalytic cracking regeneration processes that require high conversion rates. This patent proposes a fast fluidized reactor that uses the mechanism of particle agglomeration to realize the countercurrent flow of particles and gas to overcome this difficulty.

Contents of the invention

The purpose of this invention is to propose a fast fluidized bed reactor that can realize the countercurrent contact between particles and gas, and realize the non-unidirectional movement of particles and gas by using the principle that the apparent density of particles increases and the drag coefficient decreases under the piled state ; It is characterized in that: the gas enters the reactor 1 from the gas inlet 2 at the bottom of the reactor, and moves upward after being evenly distributed by the distributor 3; the particles enter the reactor 1 from the particle inlet 4 at the upper part of the reactor and move along the horizontal line The orifice plate 5 placed in a zigzag at a certain angle moves downward, and the orifice plate 5 is regularly opened with holes 6. At the same time, the small holes 6 cooperate with the orifice plate 5 so that the particles cannot fall from the holes 6 and can only pass through the overflow weir. 7 moves downward; during operation, the particle flux valve 10 is controlled to form a particle accumulation layer of a certain height on the orifice plate 5; holes 6 are regularly opened on the orifice plate 5, and the gas moves upward through the holes 6; the gas and particles are on the orifice plate 5 contacts and reacts; the gas-solid two-phase mixture on the orifice 5 is operated in a fast fluidized state to achieve good contact between the gas and solid; in the reactor 1, or an orifice with large and medium holes 6 5 is placed horizontally, matched with large and medium holes 6, so that the particles fall from the holes 6; thus the countercurrent flow of gas and particles in the reactor 1 is realized.

The diameter of the holes on the orifice plate ranges from 1 mm to less than 38 mm and greater than 100 mm to 200 mm; the opening rate is between 1% and less than 30%.

The invention has the beneficial effects of overcoming the defect that the particles in the existing fast fluidized bed reactor cannot contact the gas countercurrently, and realizing the gas-solid two-phase countercurrent flow by utilizing the accumulation state of the particles; It can ensure good contact between gas and solid two phases.

Description of drawings

Fig. 1 is a schematic diagram of the structure of a fast fluidized bed reactor in which particles with an overflow weir are in countercurrent contact with gas.

Figure 2 is a schematic diagram of the structure of a small orifice plate with an overflow weir.

Fig. 3 is a structural schematic diagram of a fast fluidized bed reactor in which particles with a medium-hole plate are in countercurrent contact with gas.

Fig. 4 is a schematic diagram of the structure of an orifice plate with a middle hole.

Fig. 5 is a schematic diagram of the structure of a fast fluidized bed reactor in which particles with large orifice plates are in countercurrent contact with gas.

Fig. 6 is a schematic diagram of the structure of an orifice plate with large holes.

Fig. 7 is a schematic structural diagram of a fast fluidized bed reactor in which particles and gas are in countercurrent contact as a catalytic cracking regenerator.

Detailed ways

The invention is a fast fluidized bed reactor capable of realizing countercurrent contact between particles and gas. The non-unidirectional movement of particles and gas is realized by using the principle that the apparent density of the particles increases and the drag coefficient decreases in the piled state; as shown in Figure 1, the gas enters the reactor 1 from the gas inlet 2 at the lower part of the reactor, and passes through Distributor 3 evenly distributes and then moves upward; particles enter reactor 1 from particle inlet 4 on the upper part of the reactor and move downward along orifice plate 5; orifice plate 5 is placed in a zigzag at a certain angle to the horizontal line, Holes 6 are regularly opened on 5, and at the same time, the small holes 6 cooperate with the orifice plate 5 so that the particles cannot fall from the holes 6 and can only move downward through the overflow weir 7 (as shown in Figure 2); the particle flux is controlled during operation The valve 10 forms a particle accumulation layer of a certain height on the orifice plate 5; the gas moves upward through the hole 6; the gas and the particles contact and react on the orifice plate 5; the gas-solid two-phase mixture on the orifice plate 5 operates in a fast flow state In order to achieve good contact between gas and solid. With the large and medium holes 6, the reactor has two other structures in which the orifice plate 5 with the large and medium holes 6 is placed horizontally (as shown in Fig. 3, Fig. 4, Fig. 5 and Fig. 6). The particles fall from the hole 6, so that the countercurrent flow of gas and particles in the reactor 1 can also be realized. The diameter of the hole 6 on the above-mentioned orifice plate 5 ranges from 1 to 200 mm; the opening ratio is between 1% and 200 mm. Between 40%.

The application of one of the application examples of the reactor in the catalytic cracking regenerator is given below to further illustrate the present invention. As shown in Figure 7, a fast fluidized bed reactor in countercurrent contact with particles and gas is used as a schematic diagram of the implementation of a catalytic cracking regenerator. The regeneration process of the catalyst is the process of using air to burn off the coke deposited on the catalyst. The spent catalyst rich in coke enters the reactor 1 from the spent catalyst inlet 4 of the regenerator 1; the air enters from the main air inlet 2 of the reactor 1; the air contacts and burns on the orifice plate 5 of the regenerated catalyst; The regenerated catalyst leaves the reactor 1 from the outlet 9 of the regenerated catalyst; the flue gas generated by combustion leaves the reactor 1 through the flue gas outlet 8; this reactor can maintain a high carbon burning intensity in the late stage of the reaction, so that the regeneration of the catalyst is more sufficient; At the same time, an external heat collector 13 and a secondary air inlet 12 can also be installed between the stages of the regenerator to adjust the heat balance of the regenerator; the form of multi-stage reaction also helps to reduce the emission of nitrides and sulfides.

Claims (2)

1. A fast fluidized bed reactor capable of realizing particle and gas countercurrent contact, the upper part of the reactor (1) is provided with a particle inlet (4) and a gas outlet (8), and the middle part is fixed with regular openings (6) orifice (5), the bottom of the reactor (1) is provided with a gas inlet (2) and a particle outlet (9); it is characterized in that: the orifice (5) is oblique to the horizontal line in the reactor (1) The corners intersect in a "Zigzag" shape, and the orifice plate (5) is provided with an overflow weir (7); the gas distributor (3) is fixed on the gas inlet (2) at the lower part of the reactor (1), and the gas inlet (2) is connected to the gas flow control valve (11), and the particle flux control valve (10) is connected to the particle outlet (9); the gas enters the reactor (1) through the gas inlet (2), and passes through the distributor (3) evenly After being distributed, it moves upwards, and its flow is regulated by the gas flow control valve (11); the particles enter the reactor (1) from the particle inlet (4) on the upper part of the reactor and move along the zigzag orifice (5) to Downward movement; during operation, the particle flux valve (10) is controlled so that a certain height of particle accumulation layer is formed on the orifice plate and moves downward through the overflow weir (7); the gas and particles are in contact with the orifice plate (5) and The reaction occurs; the gas moves upward through the hole (6); after the gas passes through the hole (6), it forms a fast fluidized dense-phase bed operating state with the particles on the orifice plate (5), so that the gas-solid two-phase mixture operates In a fast fluidized state to achieve good contact between gas and solid; the flow direction of gas and particles in the reactor is generally opposite. 2. The fast fluidized bed reactor capable of realizing countercurrent contact between particles and gas according to claim 1, characterized in that: the diameter of the holes on the orifice plate ranges from 1 millimeter to less than 38 millimeters and greater than 100 millimeters to 200 millimeters. Between millimeters; the opening rate is between 1% and less than 30%.

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