CN107177384B - A catalytic gasification device, system and method - Google Patents

Abstract

The invention relates to the technical field of catalytic gasification, in particular to a catalytic gasification device, a catalytic gasification system and a catalytic gasification method. The defects that in the prior art, when carbon monoxide and hydrogen are returned to a furnace to prepare methane, a high-temperature overheating gasifying agent is required to be provided, the energy consumption is high, the industrial amplification is difficult, and the methane content is low, the safety is poor and the oxygen consumption is high in the oxygen introducing process are overcome. The embodiment of the invention provides a catalytic gasification device, which comprises: the gasification furnace comprises a gas distribution plate, a fluidized bed reaction zone is arranged above the gas distribution plate, and the gas distribution plate is used for introducing water vapor and oxygen into a region of the fluidized bed reaction zone close to the gas distribution plate; and each gas incidence pipe is communicated with the region of the fluidized bed reaction zone far away from the gas distribution plate and is used for introducing carbon monoxide and hydrogen into the region of the fluidized bed reaction zone far away from the gas distribution plate. The embodiment of the invention is used for preparing methane by catalytic gasification.

Description

A catalytic gasification device, system and method

technical field

The present invention relates to the technical field of catalytic gasification, in particular to a catalytic gasification device, system and method.

Background technique

Coal catalytic gasification technology refers to the gasification reaction of coal with a gasification agent (composed of water vapor, hydrogen and carbon monoxide) under the catalytic action of a catalyst at a relatively low temperature to generate crude gas rich in methane. Compared with other coal gasification technologies, the coupling of the endothermic coal gasification reaction and the exothermic methanation reaction can improve the energy efficiency of the system due to the simultaneous introduction of catalysts for coal catalytic gasification and methanation reactions.

In the existing coal catalytic gasification technology, oxygen-free gasification technology is mostly used. Specifically, the gasification agent composed of water vapor, hydrogen and carbon monoxide is passed into the gasifier through the gas distribution plate at the bottom of the gasifier, so that Coal gasification reaction occurs between coal and the gasification agent, and methane is by-produced at the same time. The methane-rich crude gas generated in the gasifier is purified and separated to obtain methane-rich purified gas. Cryogenic separation obtains carbon monoxide and hydrogen, and the obtained carbon monoxide and hydrogen are mixed with steam as circulating gas and passed into the gasifier to carry out the methanation reaction under the catalytic action of the catalyst to further improve the methane production, but here During the process, since the overall reaction in the gasifier is a slightly endothermic reaction, it is necessary to overheat the gasification agent to above 800°C to promote the reaction in the gasifier, which results in high energy consumption and difficulty in industrial scale-up.

If the oxygenated gasification process is adopted, it is necessary to add part of oxygen to the gasification agent passed through the gas distribution plate at the bottom of the gasifier, and the energy required for the reaction in the gasifier is supplemented by oxygen combustion. Under the circumstance, oxygen, carbon monoxide and hydrogen cannot be introduced at the same time, which is easy to cause explosion, deflagration and other accidents, and there is a safety problem; and the strong exothermic methanation reaction in the gasifier is less, and the content of methane in the obtained crude gas lower, the oxygen consumption is higher.

In view of this, it is urgent to develop a gasifier capable of feeding oxygen, carbon monoxide and hydrogen at the same time, which can supplement the energy required for the reaction heat in the gasifier through oxygen combustion, avoid the contact of oxygen with carbon monoxide and hydrogen, and increase methane content while reducing oxygen consumption.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a catalytic gasification device, system and method, which solves the problem that the oxygen-free gasification process in the prior art consumes a lot of energy when returning carbon monoxide and hydrogen to the furnace to produce methane, and the gasification agent needs to be overheated. It has the defects of low methane content, poor safety and high oxygen consumption in the oxygen-passing process.

To achieve the above object, the present invention adopts the following technical solutions:

On the one hand, an embodiment of the present invention provides a catalytic gasification device, comprising:

A gasifier, the gasifier includes a gas distribution plate, the upper part of the gas distribution plate is a fluidized bed reaction zone, and the gas distribution plate is used to approach the gas distribution plate to the fluidized bed reaction zone. The area is vented with water vapor and oxygen;

At least one gas injection pipe, each of the gas injection pipes communicates with the region of the fluidized bed reaction zone away from the gas distribution plate, and is used for communicating with the region of the fluidized bed reaction zone away from the gas distribution plate. Enter carbon monoxide and hydrogen.

Optionally, the fluidized bed reaction zone includes a dense phase zone and a dilute phase zone in sequence from bottom to top, and each of the gas injection pipes is communicated with the dense phase zone.

Optionally, the dense phase zone includes an oxygen-containing zone and an oxygen-free zone in sequence from bottom to top, wherein the outlet of the gas injection pipe is located at the bottom of the oxygen-free zone.

Optionally, the dense phase zone has a transition zone whose bed diameter gradually expands from bottom to top.

Optionally, the included angle between the furnace wall of the gasifier corresponding to the transition zone and the vertical direction is less than or equal to 8 degrees.

Optionally, there are at least two gas injection pipes, and they are arranged in layers at different heights of the side wall of the gasifier.

Optionally, there are at least two gas injection pipes in each layer, and they are evenly distributed along the circumferential direction of the gasifier.

Optionally, one end of each of the gas injection pipes is located outside the gasifier, and the other end is flush with the inner wall of the gasifier.

Optionally, the gas injection tube has a first acute angle with the horizontal plane, and there is a second angle between the gas injection tube and the plane where the tangent of the connection point between the gas injection tube and the side wall of the gasifier is located. acute angle.

Optionally, when the gas injection pipe is inclined downward on the side wall of the gasifier, the maximum value of the first acute angle is 45 degrees; When on the side wall of the gasifier, the maximum value of the first acute angle is 15 degrees;

The second acute angle is 25-45 degrees.

Optionally, the diameter of the gas injection pipe is set so that the gas flow velocity through the gas injection pipe is 5-30 m/s.

Optionally, one end of each of the gas injection pipes is located outside the gasifier, the other end extends into the gasifier, and the end extending into the gasifier is provided with at least two through holes.

Optionally, the diameter of each of the through holes is 2-5 mm, and the diameter of the gas injection pipe is set so that the gas flow rate passing through the through holes is 10-30 m/s.

Optionally, the gas injection pipe is arranged obliquely or horizontally on the side wall of the gasifier at a third acute angle, and the third acute angle refers to the gas injection pipe and the gas injection pipe and the gas injection pipe and the gas injection pipe. The angle formed between the planes where the tangent to the connection point of the side wall of the gasifier is located.

Optionally, the gas distribution plate has an inverted conical structure, and the gas distribution plate is provided with air holes, and the diameter of the air holes is less than or equal to 5 mm.

Optionally, the number of openings of the gas holes is set so that the pressure drop of the gas distribution plate is 1/3 of the pressure drop of the gasifier.

On the other hand, an embodiment of the present invention provides a catalytic gasification system, comprising:

The above catalytic gasification device and a purification and separation system respectively communicated with the crude gas outlet of the catalytic gasification device and the inlet of the gas injection pipe;

The purification and separation system is used for separating carbon monoxide and hydrogen in the crude gas, and sending the separated carbon monoxide and hydrogen together to the gasifier.

Optionally, the purification and separation system includes a gas-solid separation system communicated with the crude gas outlet of the catalytic gasification device, and a gas-solid separation system communicated with the gas outlet of the gas-solid separation system, wherein the gas The separation system is a cryogenic separation system or a physicochemical adsorption system.

Optionally, the catalytic gasification system further includes a pressure boosting system, the inlet of the pressure boosting system is communicated with the carbon monoxide outlet and the hydrogen outlet of the gas separation system, and the outlet of the pressure boosting system is connected with the gas injection pipe. The inlet is communicated with, and the pressure boosting system is used for increasing the pressure of carbon monoxide and hydrogen to a preset value, and transporting the carbon monoxide and hydrogen whose pressure has been increased to the preset value into the gasifier.

In another aspect, an embodiment of the present invention provides a catalytic gasification method, which is applied to the catalytic gasification system as described above, including:

Water vapor and oxygen are introduced into the fluidized-bed reaction zone through the gas distribution plate, so that the solid fuel loaded with the catalyst undergoes catalytic gasification reaction with the water vapor and oxygen to generate crude gas;

Carbon monoxide and hydrogen are introduced into the region of the fluidized bed reaction zone away from the gas distribution plate through a gas injection pipe, so that carbon monoxide and hydrogen undergo a methanation reaction under the catalytic action of the catalyst carried by the solid fuel.

An embodiment of the present invention provides a catalytic gasification device. Water vapor and oxygen are introduced into the fluidized bed reaction zone through the gas distribution plate, so that the solid fuel entering the gasifier can be mixed with the water vapor and oxygen. Oxygen gasification reaction occurs in the region of the fluidized bed reaction zone near the gas distribution plate to generate crude gas rich in methane, carbon monoxide and hydrogen, and the introduction of the oxygen can provide the required energy for the gasification reaction , suitable for industrial enlargement, and at the same time, carbon monoxide and hydrogen are introduced into the region of the fluidized bed reaction zone away from the gas distribution plate through the gas injection pipe, which can be mixed with the solid fuel entering the fluidized bed reaction zone. The methanation reaction occurs under the catalytic action of the catalyst carried by the solid fuel, which is beneficial for carbon monoxide and hydrogen to be returned to the furnace to produce methane, increases the methane content in the crude gas, and also avoids the simultaneous introduction of oxygen, carbon monoxide and hydrogen. At the same time, because the methanation reaction is a strong exothermic reaction, it can also effectively reduce the oxygen consumption. It solves the problem that in the prior art, the oxygen-free gasification process needs to overheat the gasification agent to a higher temperature when the carbon monoxide and hydrogen are returned to the furnace to produce methane, the energy consumption is large, the industrial scale is difficult, and the methane content in the oxygen-passing process is low and the safety is poor. , The defect of high oxygen consumption.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only for the present invention. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic structural diagram of a catalytic gasification device provided in an embodiment of the present invention;

2 is a schematic structural diagram of the connection between a gas injection tube and a gasifier provided by an embodiment of the present invention;

3 is a schematic structural diagram of another catalytic gasification device provided in an embodiment of the present invention;

4 is a schematic structural diagram of another gas injection pipe connected to a gasifier provided in an embodiment of the present invention;

5 is a schematic structural diagram of a catalytic gasification system according to an embodiment of the present invention;

6 is a schematic structural diagram of another catalytic gasification system provided in an embodiment of the present invention;

7 is a schematic structural diagram of another catalytic gasification system provided by an embodiment of the present invention;

8 is a schematic structural diagram of yet another catalytic gasification system provided by an embodiment of the present invention;

Gasification furnace-1; gas distribution plate-11; fluidized bed reaction zone-A; gas injection pipe-2; dense phase zone-B; dilute phase zone-C; aerobic zone-B1; oxygen-free zone-B2; Slag discharge pipe-12; central jet pipe-13; transition zone-E; expansion section-F; solid fuel inlet-14; crude gas outlet-15; first acute angle-θ1; second acute angle-θ2; third acute angle- θ3; catalytic gasification unit-01; purification separation system-02; gas-solid separation system-021; cooling separation system-022; gas separation system-023; acid gas removal system-024; pressure boosting system-03; carbon monoxide and Hydrogen mixing system-025; solid fuel pretreatment system-04; crushing and screening system-041; catalyst loading system-042; drying system-043; solid fuel delivery system-05.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", The orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying The device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

On the one hand, an embodiment of the present invention provides a catalytic gasification device, see FIG. 1 , including:

Gasification furnace 1, the gasification furnace 1 includes a gas distribution plate 11, above the gas distribution plate 11 is a fluidized bed reaction zone A, and the gas distribution plate 11 is used for the fluidized bed reaction zone A Water vapor and oxygen are introduced into the area close to the gas distribution plate 11;

At least one gas injection pipe 2, each of the gas injection pipes 2 communicates with the region of the fluidized bed reaction zone A away from the gas distribution plate 11, for moving the fluidized bed reaction zone A away from the gas The area of the distribution plate 11 is vented with carbon monoxide and hydrogen.

Among them, it should be noted that the gasifier 1 is usually used for coal catalytic gasification reaction. In practical applications, coal is usually passed from the coal inlet in the middle of the gasifier 1 into the fluidized bed reaction zone A, and the coal is fed into the fluidized bed reaction zone A. The gasification agent in the bed reaction zone A undergoes a coal catalytic gasification reaction.

Here, the coal can be any solid fuel that can be gasified to produce energy as well as methane. Therefore, the fluidized bed reaction zone A refers to the solid fuel passed into the gasifier 1 and the gasification agent passed from the gas distribution plate 11 and the gas injection pipe 2 (here, the water vapor , oxygen, carbon monoxide and hydrogen are collectively referred to as the gasification agent) in the region where catalytic gasification reaction occurs, and the boundary of the fluidized bed reaction zone A may coincide with the inner wall of the gasifier 1 and the upper surface of the gas distribution plate 11. , here, as shown by the dotted line in the figure, the inner wall of the gasification furnace 1 and the upper surface of the gas distribution plate 11 are slightly moved inward to serve as the boundary of the fluidized bed reaction zone A.

The embodiment of the present invention provides a catalytic gasification device, in which steam and oxygen are introduced into the fluidized bed reaction zone A through the gas distribution plate 11, so that the solid fuel entering the gasifier 1 can be mixed with the The gasification reaction of water vapor and oxygen occurs in the fluidized bed reaction zone A near the gas distribution plate 11 to generate crude gas rich in carbon monoxide and hydrogen, and the introduction of the oxygen can provide sufficient energy for the gasification reaction. The required energy is suitable for industrial enlargement. At the same time, carbon monoxide and hydrogen are introduced into the region of the fluidized bed reaction zone A away from the gas distribution plate 11 through the gas injection pipe 2, which can be combined with entering the fluidized bed. The solid fuel in the reaction zone A undergoes a methanation reaction under the catalysis of the catalyst carried by the solid fuel, which is conducive to carbon monoxide and hydrogen returning to the furnace to produce methane, increasing the methane content in the crude gas, and avoiding the simultaneous flow of oxygen, carbon monoxide and hydrogen. In addition, the safety of catalytic gasification is ensured. At the same time, the methanation reaction is a strong exothermic reaction, which can effectively reduce the oxygen consumption. It solves the problem that in the prior art, when carbon monoxide and hydrogen are returned to the furnace to produce methane, the gasification agent needs to be overheated to a higher temperature, the energy consumption is large, the industrial amplification is difficult, and the methane content in the oxygen-passing process is low and the safety is poor. , The defect of high oxygen consumption.

In the catalytic gasification process, according to the different bed densities, the fluidized bed reaction zone A includes a dense phase zone B and a dilute phase zone C sequentially from bottom to top, and the gas injection pipe 2 is connected to the fluidized bed The reaction zone A communicates with the dense phase zone B away from the gas distribution plate 11 . In this way, the carbon monoxide and hydrogen introduced into the fluidized bed reaction zone A through the gas injection pipe 2 can fully contact the bed material of the dense phase zone B, and the methanation reaction occurs under the catalytic action, which is beneficial to the generation of methane at the same time. A large amount of heat is released and transferred to the bed material, which can supplement the heat required for the catalytic gasification reaction.

There is no obvious boundary between the dense phase region B and the dilute phase region C, which is only an example for illustrating the present invention, and, in practical applications, the dense phase region B and the dilute phase region C The boundary of the dilute phase region C coincides with the furnace wall of the gasifier 1 .

It should be noted that water vapor and oxygen are introduced into the fluidized-bed reaction zone A through the gas distribution plate 11, and the water vapor and oxygen gradually rise in the gasifier 1, which is the same as the introduction into the dense-phase zone B. The catalyst-loaded solid fuel undergoes a catalytic gasification reaction to generate crude gas rich in methane, carbon monoxide and hydrogen. The specific reaction formula is as follows:

2C+2H ₂ O→2H ₂ +2CO (1)

CO+H ₂ O→CO ₂ +H ₂ (2)

3H ₂ +CO→CH ₄ +3H ₂ O (3)

2C+O ₂ →2CO (4)

C+O ₂ →CO ₂ (5)

As the bed rises, the oxygen reacts with the carbon in the fluidized bed reaction zone A and is gradually consumed completely. Here, the bottom area where oxygen is not completely consumed is the aerobic zone B1, and the area after the oxygen is completely consumed is the oxygen-free zone B2.

Based on this, in an embodiment of the present invention, continuing to refer to FIG. 1 , the dense phase region B includes an oxygen-containing region B1 and an oxygen-free region B2 in sequence from bottom to top, and the outlet of the gas injection pipe 2 is located in the non-oxygen region B2. Bottom of oxygen zone B2. In this way, on the one hand, the risk of contacting carbon monoxide and hydrogen with oxygen can be avoided, and on the other hand, the residence time of carbon monoxide and hydrogen in the fluidized bed reaction zone A can be extended to the greatest extent, and the methanation reaction can be promoted.

Among them, it should be noted that in addition to being used as a gasification agent for catalytic gasification reaction with fuel, water vapor and oxygen also have a fluidizing effect. In practical applications, the bottom of the gas distribution plate 11 is also connected with a slag discharger. Pipe 12, the inner side of the slag discharge pipe 12 is provided with a central jet pipe 13 that communicates with the aerobic zone B1, and the air holes on the gas distribution plate 11 and the central jet pipe 13 can be fed with different concentrations of gas. Water vapor and oxygen are introduced into the annular gap formed by the central jet pipe 13 and the slag discharge pipe 12 to fluidize the fuel in the fluidized bed reaction zone A.

During this process, the introduction amount of water vapor and oxygen, and the introduction ratio of water vapor and oxygen can also be adjusted to properly supplement the energy in the gasifier 1 and at the same time ensure the flow field in the gasifier 1. distributed.

In yet another embodiment of the present invention, the catalytic gasification device further includes a solid fuel inlet 14 disposed in the oxygen-free zone B2 or the dilute phase zone C. The fuel is introduced into the gasifier through the solid fuel inlet 14, so that the fuel is distributed in the fluidized bed reaction zone A in the gasifier 1. On the contrary, according to the density of the fuel in the fluidized bed reaction zone A, The fluidized bed reaction zone A is a dense phase zone B and a dilute phase zone C from bottom to top.

In an embodiment of the present invention, the gas distribution plate 11 has an inverted conical structure, and the gas distribution plate 11 is provided with air holes, and the diameter of the air holes is less than or equal to 5 mm. By limiting the structure of the gas distribution plate 11 , the uniform distribution of the gasification agent can be achieved, and the stability of the flow field of the fluidized bed gasifier can be promoted.

Wherein, the number of openings of the gas holes can be set so that the pressure drop of the gas distribution plate 11 is 1/3 of the pressure drop of the bed in the dense phase zone of the gasifier 1 . In this way, the short circuit of the gasification agent is avoided, which is beneficial to the uniform distribution of the gasifier and the improvement of the fluidization quality.

In another embodiment of the present invention, the dense phase region B has a transition region E with a bed diameter gradually expanding from bottom to top, so as to avoid the occurrence of flow dead zone caused by sudden change of bed diameter, which is not conducive to the reaction field and temperature field in the bed. Evenly distributed.

Wherein, the transition zone E may be located at the bottom of the dense phase zone B.

In another embodiment of the present invention, the included angle between the furnace wall of the gasifier 1 corresponding to the transition zone E and the vertical direction is less than or equal to 8 degrees, so as to avoid the angle being too large and the diameter changing too much, which may cause flow in the bed The site where the quality of the chemical is degraded and the dead zone appears locally.

In an embodiment of the present invention, there are at least two gas injection pipes 2 , which are penetrated in layers at different heights of the side wall of the gasifier 1 . In this way, the carbon monoxide and hydrogen gas introduced into the fluidized bed reaction zone A through the gas injection pipe 2 can be fully contacted with the bed materials of different heights, and the methanation reaction occurs under the catalytic action, and a large amount of heat transfer is released while generating methane. The heat required for the catalytic gasification reaction can be supplemented by supplying different heights of bed materials.

In a preferred embodiment of the present invention, there are at least two gas injection pipes 2 in each layer, and they are evenly distributed along the circumferential direction of the gasifier 1 . Carbon monoxide and hydrogen can be uniformly introduced into the gasifier 1 , so that the carbon monoxide and hydrogen are in closer contact with the solid fuel, which is beneficial to the gas-solid reaction and methanation reaction and the flow field distribution in the gasifier 1 .

In the first possible implementation manner of the present invention, as shown in FIG. 1 , one end of each of the gas injection pipes 2 is located outside the gasifier 1 , and the other end is flat with the inner wall of the gasifier 1 . together. The carbon monoxide and hydrogen introduced through the gas injection pipe 2 can be distributed along the inner wall of the gasifier 1, fully contacted with the bed material in the dense phase zone B, and a methanation reaction occurs under the action of the catalyst, generating methane and releasing a large amount of heat and transfer to the dense phase bed material.

In this possible implementation, referring to FIG. 2 , each of the gas injection pipes 2 has a first acute angle θ1 with the horizontal plane, and the gas injection pipes 2 are connected with the gas injection pipes 2 and the gasifier. There is a second acute angle θ2 between the planes where the tangent of the side wall connecting point is located. In this way, when carbon monoxide and hydrogen are introduced into the gasifier 1 through the gas injection pipe 2, the carbon monoxide and hydrogen can form a swirling effect in the gasifier 1, and the swirling effect can interact with the gasifier 1. The flow field inside is better integrated, and at the same time, the bubbles formed in the gasifier can be broken to realize the secondary distribution of the gas.

Preferably, when the gas injection pipe 2 is disposed on the side wall of the gasifier 1 inclined downward, the maximum value of the first acute angle θ1 may be 45 degrees; when the gas injection pipe 2 is inclined upward When disposed on the side wall of the gasifier 1, the maximum value of the first acute angle θ1 may be 15 degrees; the second acute angle may be 25-45 degrees.

In this possible implementation manner, the diameter of the gas injection pipe 2 is set so that the gas flow velocity through the gas injection pipe 2 is 5-30 m/s. The diameter of the gas injection pipe 2 is directly related to the gas flow rate through the gas injection pipe 2. Generally, under the condition of a certain flow rate, the larger the pipe diameter of the gas injection pipe 2, the smaller the gas flow rate, and the smaller the pipe diameter, and the gas The higher the flow rate. The gas flow rate of the gas injection pipe 2 is controlled within this range, and there is a large tangential component, which is conducive to the uniform distribution of carbon monoxide and hydrogen, and increases the residence time of carbon monoxide and hydrogen in the dense phase zone, so that carbon monoxide and hydrogen are mixed with solid The fuel contact is closer, which is conducive to the gas-solid reaction and methanation reaction. At the same time, the existence of the tangential component can break the bubbles existing in the center of the bed, realize the redistribution of the gas phase, and strengthen the degree of turbulence in the furnace. , strengthen the back-mixing and gas-solid contact of carbon monoxide and hydrogen, and avoid the loss of flow caused by the formation of throttling in the furnace.

In the second possible implementation manner of the present invention, as shown in FIG. 3 , one end of each of the gas injection pipes 2 is located outside the gasifier 1 , and the other end extends into the gasifier 1 and extends into the gasifier 1 . At least two through holes are provided at one end entering into the gasifier 1 . When carbon monoxide and hydrogen are introduced through the gas injection pipe, the carbon monoxide and hydrogen can be distributed in the gasifier through the through holes, and the residence time of carbon monoxide and hydrogen in the dense phase region can also be increased, so that carbon monoxide and hydrogen can interact with each other. The solid fuel contact is more closely, which is conducive to the gas-solid reaction and the methanation reaction.

Wherein, the gas injection tube 2 may be a cylindrical structure, and the through holes may be uniformly distributed on the side wall of the middle and lower part of the cylindrical structure. In this way, it is favorable for carbon monoxide and hydrogen to be uniformly distributed in the gasifier 1 .

In a preferred embodiment of the present invention, the diameter of each of the through holes is 2-5 mm, and the diameter of the gas injection pipe 2 is set so that the gas flow velocity through the through holes is 10-30 m/s. By setting the diameter of the gas injection pipe 2 so that the gas flow rate through the through hole is within the above range, the introduced carbon monoxide and hydrogen can be evenly distributed, the degree of turbulence in the furnace can be enhanced, and the carbon monoxide and hydrogen can be enhanced. The back-mixing and gas-solid contact promote the methanation reaction.

In this possible implementation, referring to FIG. 4 , the gas injection pipe 2 is disposed obliquely or horizontally on the side wall of the gasifier 1 at a third acute angle θ3, and the third acute angle θ3 refers to the The angle formed between the gas injection pipe 2 and the plane where the tangent of the connection point between the gas injection pipe 2 and the side wall of the gasifier is located. In this way, the gas distribution and the flow field in the furnace can be further optimized, the degree of turbulence in the furnace can be strengthened, the back-mixing and gas-solid contact of carbon monoxide and hydrogen can be strengthened, and the loss of fluidization can be avoided.

Wherein, the gas injection pipe 2 may be inclined upward, or may be disposed on the side wall of the gasification furnace 1 inclined downward, which is not limited herein.

Further, as shown in FIG. 1 , the gasifier 1 may further include an enlarged section F disposed above the fluidized bed reaction zone A, and a crude gas outlet 15 is provided above the enlarged section F. In this way, when the methane-rich crude gas generated by the catalytic gasification reaction and the methanation reaction in the fluidized bed reaction zone A enters the subsequent purification and separation system through the crude gas outlet 15, the enlarged section can effectively reduce the crude gas. The gas velocity of the gas can reduce the amount of semi-coke or solid dust entrained in the crude gas, which is beneficial to the subsequent purification and separation treatment.

On the other hand, an embodiment of the present invention provides a catalytic gasification system, see FIG. 5 , including:

The above catalytic gasification device 01 and the purification and separation system 02 respectively communicated with the crude gas outlet of the catalytic gasification device 01 and the inlet of the gas injection pipe 2;

The purification and separation system 02 is used to separate the carbon monoxide and hydrogen in the crude gas, and send the separated carbon monoxide and hydrogen to the gasifier 1 together.

The embodiment of the present invention provides a catalytic gasification system, by respectively connecting the crude gas outlet of the catalytic gasification device 01 and the inlet of the gas injection pipe 2 with the purification and separation system 02, the purification and separation system 02 Purify and separate the methane-rich crude gas produced by the catalytic gasification device 01, separate carbon monoxide and hydrogen, and pass them into the gasifier 1 through the gas injection pipe 2, so that carbon monoxide and hydrogen can be recycled back to the furnace. Produce methane, increase the methane content, and can provide heat for the gasification reaction in the gasifier through continuous oxygen supply, avoid additional heating, and avoid the explosion of carbon monoxide and hydrogen in contact with oxygen to ensure the safety of catalytic gasification reaction. , effectively reducing oxygen consumption. The invention solves the defects of high energy consumption when the carbon monoxide and hydrogen are returned to the furnace to make methane in the prior art, and the defects of low methane content, poor safety and high oxygen consumption in the oxygen-passing process are not suitable for industrial amplification.

In an embodiment of the present invention, the purification and separation system 02 includes a gas-solid separation system 021 communicated with the crude gas outlet of the catalytic gasification device 01 , and a cooling system 021 communicated with the gas outlet of the gas-solid separation system 021 The separation system 022 and the gas separation system 023 communicated with the gas outlet of the cooling separation system 022, wherein the gas separation system 023 is a cryogenic separation system or a physicochemical adsorption system. Through the gas-solid separation system 021, the semi-coke or solid dust carried by the crude gas can be separated. At this time, the crude gas contains a large amount of light oil and heavy oil, and the light oil is separated by the cooling separation system 022. At this time, the purified gas obtained is a gas rich in methane, carbon monoxide and hydrogen. The cryogenic separation system can separate methane, carbon monoxide and hydrogen, and it is easy to achieve, through physical The chemical adsorption system can quickly separate methane, carbon monoxide and hydrogen, and realize the return of carbon monoxide and hydrogen.

Wherein, the cooling and separation system 022 can be in the form of direct cooling or indirect cooling, and the cooling medium is preferably water. In this way, while cooling the crude gas, it can absorb heat and by-produce water vapor, and the water vapor can pass through the gas. The distribution plate is passed into the gasifier 1 .

Among them, it should be noted that in the catalytic gasification reaction, according to the type of solid fuel, the content of sulfur content is also different, and the content of acid gas such as sulfur dioxide and hydrogen sulfide in the obtained crude gas is also different. The process conditions are different, and the content of carbon dioxide obtained is also different. Therefore, preferably, in an embodiment of the present invention, referring to FIG. 6 , an acid is also provided between the gas separation system 023 and the cooling separation system 022 A gas removal system 024, the acid gas removal system 024 is used for removing acid gas in the crude gas. In this way, it is beneficial to protect the cryogenic separation system or the physicochemical adsorption separation system and avoid acid gas corrosion.

In yet another embodiment of the present invention, referring to FIG. 7 , the catalytic gasification system further includes a pressure boosting system 03, and the inlet of the pressure boosting system 03 is communicated with the carbon monoxide outlet and the hydrogen outlet of the gas separation system 02, so The outlet of the pressure boosting system 03 is communicated with each of the gas injection pipes 2, and the pressure boosting system 03 is used to increase the pressure of carbon monoxide and hydrogen to a preset value, and increase the pressure to a preset value of carbon monoxide and hydrogen into the gasifier 1 .

Since the inside of the gasifier 1 is in a high-pressure environment, the carbon monoxide and hydrogen are boosted by the boosting system 03 , so that the carbon monoxide and the hydrogen can be smoothly transported into the gasifier 1 .

Wherein, the pressure boosting system 03 may be a syngas compressor or a high-pressure steam extraction pump. The high-pressure steam for driving the high-pressure steam extraction pump may come from the water vapor produced by the cooling separation system 022 .

The preset value is not limited. Since the gasifier is in a high-pressure environment, the preset value needs to be higher than the pressure in the gasifier 1 .

Preferably, the difference between the preset value and the pressure in the gasifier 1 is greater than or equal to 0.5 MPa.

In an embodiment of the present invention, referring to FIG. 6 , the catalytic gasification system may further include a carbon monoxide and hydrogen mixing system 025 for mixing carbon monoxide and hydrogen evenly.

In yet another embodiment of the present invention, referring to FIG. 8 , the catalytic gasification system further includes a solid fuel pretreatment system 04 , and the solid fuel pretreatment system 04 includes a crushing and screening system 041 , a catalyst loading system 042 and a drying system 043, the crushing and screening system 041 is used for crushing and sieving the solid fuel into powder, the catalyst loading system 042 is used for catalyst loading of the solid fuel, and the drying system 043 is used for the catalyst-loaded solid fuel Dry.

In a preferred embodiment of the present invention, the coal catalytic gasification system further includes a solid fuel delivery system 05 for delivering solid fuel into the gasifier through the solid fuel inlet 14 1 in.

In yet another aspect, an embodiment of the present invention provides a catalytic gasification method, which is applied to the above-mentioned coal catalytic gasification system, including:

Water vapor and oxygen are introduced into the fluidized bed reaction zone through the gas distribution plate, so that the solid fuel loaded with the catalyst undergoes gasification reaction with the water vapor and oxygen to generate crude gas;

Carbon monoxide and hydrogen are introduced into the region of the fluidized bed reaction zone away from the gas distribution plate through a gas injection pipe, so that carbon monoxide and hydrogen undergo a methanation reaction under the catalytic action of the catalyst carried by the solid fuel.

The embodiment of the present invention provides a catalytic gasification method. By passing water vapor, oxygen, and carbon monoxide and hydrogen separated from crude coal gas into a gasifier in different regions, it is possible to avoid explosion caused by contact of oxygen with carbon monoxide and hydrogen. Oxygen combustion provides heat for the gasification reaction in the gasifier, avoids additional heating, and is suitable for industrial scale-up. At the same time, carbon monoxide and hydrogen can be returned to the furnace to produce methane, and the methane content in the crude gas produced by catalytic gasification can be increased. , the methanation reaction is a strong exothermic reaction, which can effectively reduce the oxygen consumption.

Wherein, the particle size of the catalyst-loaded solid fuel, the catalyst loading amount and the water content of the solid fuel are not limited.

In an embodiment of the present invention, the particle size of the solid fuel is less than or equal to 5 mm, the catalyst loading of the solid fuel accounts for 5-15% of the mass of the solid fuel, and the dried catalyst-loaded solid fuel contains The amount of water is less than or equal to 5%. The moisture content refers to the mass percentage content of moisture in the dried catalyst-loaded solid fuel. It is beneficial to the catalytic gasification reaction and the methanation reaction.

Wherein, the type of the solid fuel is not limited, and the solid fuel may be lignite, bituminous coal, sub-bituminous coal, anthracite, biomass coal or petroleum coke.

The type of the catalyst is also not limited, and the catalyst can be one or several combinations of alkali metal catalysts, alkaline earth metal catalysts and transition metal catalysts.

Preferably, the catalyst is an alkali metal catalyst.

The temperature and pressure of the catalytic gasification reaction are not limited. Preferably, the temperature of the catalytic gasification reaction is 650-750° C., and the pressure is 3-4.5 MPa.

Hereinafter, the embodiments of the present invention will illustrate the present invention through examples. These embodiments are only examples provided to specifically illustrate the present invention, and those skilled in the art will appreciate that the scope of the present invention is not limited by these embodiments.

It should be noted that, in order to objectively illustrate the technical effects of the embodiments of the present invention, the solid fuels entering the gasifier in the following embodiments are all prepared and obtained from the same coal type through the same process.

Specifically, the lignite is crushed and screened to obtain pulverized coal with a size of less than 5 mm, and the pulverized coal is loaded with a catalyst (the catalyst is an alkali metal catalyst) by an impregnation method, so that the loading of the catalyst accounts for 5-15% of the mass of the dry coal pulverized coal. %; the pulverized coal loaded with the catalyst is dried to a moisture content of less than or equal to 5% to obtain raw coal for catalytic coal gasification.

Example

The raw coal for catalytic coal gasification obtained above is divided into at least three equal parts and subjected to a coal catalytic gasification reaction in a gasifier as shown in FIG. 8 . The coal catalytic gasification process of each aliquot of the raw coal for catalytic coal gasification is as follows:

Referring to FIG. 8 , the raw coal for coal catalytic gasification is transported into the gasifier 1 through the feeding system 05, and at the same time, water vapor and oxygen are introduced through the gas distribution plate 11 at the bottom of the gasifier 1, so that the water vapor and Oxygen and pulverized coal undergo a catalytic coal gasification reaction at 650-750°C and 3-4.5MPa in a gasifier to generate crude gas rich in methane, carbon monoxide and hydrogen. The specific reaction process is as follows:

2C+2H ₂ O→2H ₂ +2CO (1)

CO+H ₂ O→CO ₂ +H ₂ (2)

3H ₂ +CO→CH ₄ +3H ₂ O (3)

2C+O ₂ →2CO (4)

C+O ₂ →CO ₂ (5)

Wherein, the methane content in the obtained crude gas is about 20%-26% of the dry coal powder, and the effective gas content is 50%-80%.

The obtained crude gas is subjected to gas-solid separation and cooling separation, and the synthesis gas obtained by cooling and separation is passed into the acid gas removal system to remove carbon dioxide and hydrogen sulfide gas therein, and then the obtained synthesis gas is passed through cryogenic cooling. Separation or physicochemical adsorption separation separates methane, carbon monoxide and hydrogen, and mixes the carbon monoxide and hydrogen obtained by separation through a mixing system, and then increases the pressure through a pressure boosting system to a degree greater than or equal to the pressure in the gasifier. It is equal to 0.5MPa, and it is transported into the oxygen-free zone in the gasifier 1 through the gas injection pipe 2. At this time, the carbon monoxide and hydrogen undergo a methanation reaction under the catalytic action of the catalyst carried by the coal and are converted into methane, and so on. Recycle, and finally obtain crude gas with high methane content.

The catalytic gasification reaction of coal is carried out by using the coal catalytic gasification device provided by this patent and the existing coal catalytic gasification device, and the index comparison is shown in Table 1 below. In the shown aerobic circulating gas returning gasifier, the existing coal catalytic gasification devices are respectively an oxygen-free circulating gas returning gasifier and an oxygen-free circulating gas returning gasifier.

Table 1

As can be seen from Table 1, the catalytic gasification device provided by the embodiment of the present invention passes water vapor and oxygen into the gasifier through a gas distribution plate, and passes carbon monoxide and hydrogen as circulating gas into the gasifier through a gas injection pipe, Compared with the existing oxygen-free circulating gas return gasifier, the required temperature of the gasifying agent is lower, which can reduce energy consumption, improve carbon conversion rate, and has strong industrial realizability. Compared with the gas return gasifier, due to the strong exotherm of the methanation reaction, the oxygen consumption can be effectively reduced, and the final methane content is higher, the cold gas efficiency is higher, and the energy thermal efficiency is also improved to a certain extent.

To sum up, water vapor and oxygen are introduced into the fluidized bed reaction zone through the gas distribution plate, so that the solid fuel entering the gasifier can be mixed with the water vapor and oxygen in the fluidized bed. The gasification reaction occurs in the region of the reaction zone close to the gas distribution plate to generate crude gas rich in methane, carbon monoxide and hydrogen, and the introduction of the oxygen can provide the required energy for the gasification reaction, save energy consumption, and is suitable for At the same time, carbon monoxide and hydrogen are introduced into the area of the fluidized bed reaction zone away from the gas distribution plate through the gas injection pipe, which can avoid the explosion of oxygen, carbon monoxide and hydrogen when the gas is introduced at the same time, and ensure that the coal catalytic gas In addition, carbon monoxide and hydrogen are continuously returned to the furnace and the solid fuel entering the fluidized bed reaction zone undergoes a methanation reaction under the catalytic action of the catalyst carried by the solid fuel, which is beneficial to increase the methane content in the crude gas. , reduce the cost of methane; at the same time, the strong exothermic reaction of methanation provides heat for the gasifier, and the oxygen consumption is greatly reduced. It solves the problem that in the prior art, when carbon monoxide and hydrogen are returned to the furnace to produce methane, the gasification agent needs to be overheated to a higher temperature, the energy consumption is large, the industrial amplification is difficult, and the methane content in the oxygen-passing process is low and the safety is poor. , The defect of high oxygen consumption.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (15)

1. a catalytic gasification device, is characterized in that, comprises: A gasifier, the gasifier includes a gas distribution plate, the upper part of the gas distribution plate is a fluidized bed reaction zone, and the gas distribution plate is used to approach the gas distribution plate to the fluidized bed reaction zone. The area is vented with water vapor and oxygen; At least one gas injection pipe, each of the gas injection pipes communicates with the region of the fluidized bed reaction zone away from the gas distribution plate, and is used for communicating with the region of the fluidized bed reaction zone away from the gas distribution plate. into carbon monoxide and hydrogen; The fluidized bed reaction zone includes a dense phase zone and a dilute phase zone sequentially from bottom to top, and each of the gas injection pipes is communicated with the dense phase zone; The dense phase zone includes an oxygen-free zone and an oxygen-free zone in sequence from bottom to top, wherein the outlet of the gas injection pipe is located at the bottom of the oxygen-free zone; There are at least two gas injection pipes, and they are arranged in layers at different heights of the sidewall of the gasifier; The gas injection pipe has a first acute angle with the horizontal plane, and a second acute angle is formed between the gas injection pipe and the plane where the tangent of the connection point between the gas injection pipe and the side wall of the gasifier is located; When the gas injection pipe is disposed on the side wall of the gasifier inclined upward, the maximum value of the first acute angle is 15 degrees; The second acute angle is 25-45 degrees. 2. The catalytic gasification device according to claim 1, characterized in that: The dense phase zone has a transition zone with the bed diameter gradually expanding from bottom to top. 3. The catalytic gasification device according to claim 2, characterized in that: The included angle between the furnace wall of the gasifier corresponding to the transition zone and the vertical direction is less than or equal to 8 degrees. 4. The catalytic gasification device according to claim 1, characterized in that: There are at least two gas injection pipes in each layer, and they are evenly distributed along the circumferential direction of the gasifier. 5. The catalytic gasification device according to claim 1, characterized in that: One end of each of the gas injection pipes is located outside the gasifier, and the other end is flush with the inner wall of the gasifier. 6. The catalytic gasification device according to claim 5, characterized in that: The diameter of the gas injection pipe is set so that the gas flow velocity through the gas injection pipe is 5-30 m/s. 7. The catalytic gasification device according to claim 1, wherein, One end of each of the gas injection pipes is located outside the gasifier, the other end extends into the gasifier, and the end extending into the gasifier is provided with at least two through holes. 8. The catalytic gasification device according to claim 7, characterized in that: The diameter of each of the through holes is 2-5 mm, and the diameter of the gas injection pipe is set so that the gas flow velocity through the through holes is 10-30 m/s. 9. The catalytic gasification device according to claim 7, characterized in that: The gas injection pipe is arranged obliquely or horizontally on the side wall of the gasifier at a third acute angle, and the third acute angle refers to the distance between the gas injection pipe and the gas injection pipe and the gasifier. The angle between the planes on which the tangent to the side wall connection point lies. 10. The catalytic gasification device according to claim 1, characterized in that: The gas distribution plate has an inverted conical structure, and the gas distribution plate is provided with air holes, and the diameter of the air holes is less than or equal to 5 mm. 11. The catalytic gasification device according to claim 10, characterized in that: The opening number of the gas holes is set so that the pressure drop of the gas distribution plate is 1/3 of the pressure drop of the dense phase bed of the gasifier. 12. A catalytic gasification system, comprising: The catalytic gasification device according to any one of claims 1 to 11, and a purification and separation system respectively communicated with the crude gas outlet of the catalytic gasification device and the inlet of the gas injection pipe; The purification and separation system is used for separating the carbon monoxide and hydrogen in the crude gas, and sending the separated carbon monoxide and hydrogen together to the gasifier. 13 . The catalytic gasification system according to claim 12 , wherein the purification and separation system comprises a gas-solid separation system in communication with the crude gas outlet of the catalytic gasification device, and a gas-solid separation system with the gas-solid separation system. 14 . The gas separation system is connected with the gas outlet of the device, wherein the gas separation system is a cryogenic separation system or a physical and chemical adsorption system. 14. The catalytic gasification system of claim 13, wherein: The catalytic gasification system further comprises a pressure boosting system, the inlet of the pressure boosting system is communicated with the carbon monoxide outlet and the hydrogen outlet of the gas separation system, and the outlet of the boosting system is communicated with the inlet of the gas injection pipe, The pressure raising system is used for raising the pressure of carbon monoxide and hydrogen to a preset value, and sending the carbon monoxide and hydrogen whose pressure has been raised to the preset value into the gasifier. 15. A catalytic gasification method, characterized in that, applied to the catalytic gasification system according to any one of claims 12-14, comprising: Water vapor and oxygen are introduced into the fluidized-bed reaction zone through the gas distribution plate, so that the solid fuel loaded with the catalyst undergoes catalytic gasification reaction with the water vapor and oxygen to generate crude gas; Carbon monoxide and hydrogen are introduced into the region of the fluidized bed reaction zone away from the gas distribution plate through a gas injection pipe, so that carbon monoxide and hydrogen undergo a methanation reaction under the catalytic action of the catalyst carried by the solid fuel.

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