Material returning device and coal gas generating system

Abstract

The utility model discloses a material returning device and a coal gas generation system, and belongs to the technical field of fluidized bed gasification. The material returning device comprises a gas-solid separator, the discharging end of the gas-solid separator is connected with a vertical pipe, and the vertical pipe is connected with a material returning pipe used for being communicated with a furnace body. A nozzle is arranged at the junction of the vertical pipe and the material returning pipe, the spraying direction of the nozzle faces the material returning pipe, and meanwhile local low pressure is generated in the area of the junction of the vertical pipe and the material returning pipe. Therefore, stable pneumatic conveying and material returning circulation can be formed in the material returning pipe, and compared with a traditional mode that passive inclined pipe material sliding is changed into an active blowing mode through gravity, material returning is more stable and controllable. Besides, according to the coal gas generating system, steam can be jetted through the nozzle, a local low-pressure area can be formed at the bottom of the vertical pipe, and therefore the height requirements of a vertical pipe material layer air seal and a material returning pipe can be lowered, the height requirement of the upper space of a furnace body connected with the vertical pipe material layer air seal and the material returning pipe is lowered, and finally the construction cost can be greatly lowered.

Description

Technical Field

[0001] The utility model belongs to the technical field of fluidized bed gasification, and more specifically, relates to a return device and a coal gas generation system. Background Art

[0002] Coal gasification is an important form of clean and efficient utilization of coal. Fluidized bed gasifiers are widely used to achieve clean and efficient gasification of coal due to advantages such as high gasification intensity, uniform temperature inside the furnace, and good gas-solid contact effect. However, existing fluidized bed gasifiers have the problem of large dust content in the outlet gas. If the entrained fine particles cannot be efficiently utilized, the system efficiency will be greatly reduced.

[0003] In the prior art, a gas-solid separation device is usually added after the fluidized bed gasifier to separate the fly ash entrained in the raw gas, and then it is returned to the fluidized bed gasifier through a return system for continuous conversion to improve the overall system utilization efficiency. For example, in the patent of CN112833415A, a pulverized coal preheating device and a pulverized coal combustion system having the same are disclosed. This application includes a fluidized reaction unit with a reaction unit outlet and a return port; a cyclone separator, the inlet of the cyclone separator is connected to the reaction unit outlet, the cyclone separator includes a cylindrical part at the upper part and a conical part at the lower part, and the cyclone separator also has a central cylinder located on the upper side of the cylindrical part as the gas outlet of the cyclone separator; a return pipe, the return pipe is directly connected between the bottom end of the conical part and the return port, wherein: the included angle α between the connection line between the bottom end of the conical part and the return port and the vertical direction is α≤45°. The return section of this application is an inclined pipe structure, and the material separated by the cyclone separator directly enters the return section through the leg, and the automatic return of the separated material is realized by using the gravity of the separated material and the vertical downward and inclined return section structure of the separator.

[0004] Another example is that in the patent of CN109022044A, a coal gasification reaction device is disclosed. In this application, an exhaust pipe is provided on the furnace body; the exhaust pipe is used to introduce the raw gas generated by the coal gasification reaction in the furnace body into the gas-solid separation device; the gas-solid separation device is used to separate the fly ash in the raw gas; the return pipe is used to return the fly ash separated by the gas-solid separation device to the furnace body.

[0005] The above applications can all separate the fly ash entrained in the raw gas and return it to the furnace body for continuous conversion to improve the system utilization rate. However, the fly ash is mainly transported by its own gravity, and its transportation efficiency needs to be improved; at the same time, the fly ash is prone to accumulation, resulting in pipeline blockage. Summary of the Utility Model

[0006] 1. Problems to be Solved

[0007] In view of the problems of the existing return material device, such as low return material efficiency and easy accumulation of return material causing pipeline blockage, the present utility model provides a return material device. The return material device of the present utility model uses pneumatic force for return material, which not only speeds up the return material transportation but also effectively reduces the risk of pipeline blockage.

[0008] In addition, the present utility model also proposes a gas generation system, which can effectively reduce the overall height of gas generation, thereby reducing the equipment input cost.

[0009] 2. Technical solutions

[0010] In order to solve the above problems, the technical solutions adopted by the present utility model are as follows:

[0011] A return material device of the present utility model includes a gas-solid separator, the discharge end of the gas-solid separator is connected to a riser pipe, and the riser pipe is connected to a return material pipe for communicating with the furnace body;

[0012] A nozzle is provided at the junction of the riser pipe and the return material pipe, the blowing direction of the nozzle faces the return material pipe, and at the same time, a local low pressure is generated in the area where the riser pipe and the return material pipe meet.

[0013] Further, the riser pipe is vertically arranged, the return material pipe is horizontally arranged, and the local low pressure generated at the nozzle outlet position is lower than 10 Kpa.

[0014] Further, the nozzle is a Venturi nozzle, and the gas-solid separator is a cyclone separator.

[0015] Further, the gas medium introduced into the nozzle is steam or inert gas.

[0016] A gas generation system of the present utility model includes a furnace body and a gas-solid separator that are interconnected. It is characterized in that: the discharge end of the gas-solid separator is connected to a riser pipe, and the riser pipe is connected to a return material pipe for communicating with the furnace body;

[0017] A nozzle is provided at the junction of the riser pipe and the return material pipe, the blowing direction of the nozzle faces the return material pipe, and at the same time, a local low pressure is generated at the outlet end of the nozzle.

[0018] Further, the riser pipe and the return material pipe are perpendicularly intersected.

[0019] Further, the nozzle is a Venturi nozzle, and the local low pressure generated at the nozzle is lower than 10 Kpa.

[0020] Further, a air distribution device is provided in the area near the lower part of the furnace body, and the air distribution device is located below the interface of the return material pipe.

[0021] Further, a gasifying agent is introduced into the bottom of the furnace body and enters the air distribution device as a fluidizing and reaction medium. The gasifying agent is a gas that can undergo a coal gasification reaction with the fuel.

[0022] Further, the gasifying agent is air, oxygen or steam; the gas medium introduced into the nozzle is steam or inert gas.

[0023] 3. Beneficial effects

[0024] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0025] (1) In a return device of the present utility model, a nozzle is provided at the junction of the riser and the return pipe. By means of jetting steam through the nozzle, a stable pneumatic conveying return material cycle is formed in the return pipe. Compared with the conventional passive inclined pipe chute feeding by gravity in the existing industry, it is changed to an active blowing method, making the return material more stable and controllable.

[0026] (2) In a coal gas generation system of the present utility model, steam can be jetted through the nozzle, which can form a local low-pressure area at the bottom of the riser, thereby reducing the requirements for the height of the gas seal of the riser material layer and the return pipe, further reducing the height requirements for the upper space of the furnace body connected thereto, and ultimately significantly reducing the construction cost. Description of the drawings

[0027] Figure 1 is a schematic structural diagram of a coal gas generation system of the present utility model;

[0028] Figure 2 is a partial structural diagram of the return device of the present utility model.

[0029] In the figure: 1. Furnace body; 2. Gas-solid separator; 3. Riser; 4. Return pipe; 5. Nozzle; 6. Air distribution device. Specific embodiments

[0030] To further understand the content of the present utility model, the present utility model will be described in detail with reference to the accompanying drawings.

[0031] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] The present utility model will be further described below in conjunction with specific embodiments.

[0033] Referring to Figure 1 、 Figure 2 As shown, a return material device in this embodiment includes a gas-solid separator 2, a riser 3, and a return pipe 4. The gas-solid separator 2 is provided with an air inlet, an air outlet, and a discharge outlet. Among them, the air inlet on the gas-solid separator 2 is arranged at a position close to the top for communicating with the furnace body 1; at the same time, the dusty gas enters the gas-solid separator 2 through this air inlet for gas-solid separation. The air outlet is located at the top of the gas-solid separator 2 for discharging the separated gas from the gas-solid separator 2. The discharge outlet is located at the bottom of the gas-solid separator 2 and is connected to a riser 3, and this riser 3 is connected to the furnace body 1 through a return pipe 4. The separated solid materials sequentially pass through the riser 3 and the return pipe 4 and return to the furnace body 1 to continue the conversion.

[0034] In order to enable the materials to return to the furnace body 1 more quickly and stably, in this embodiment, a nozzle 5 is provided at the junction of the riser 3 and the return pipe 4, and the blowing direction of this nozzle 5 faces the return pipe 4. By introducing a gas medium into this nozzle 5 and then spraying, a stable pneumatic conveying return material cycle can be formed in the return pipe 4. Compared with the conventional passive inclined pipe chute feeding in the existing industry, it is changed to an active blowing method, making the return material more stable and controllable. At the same time, the high-speed spraying at the nozzle outlet position generates a local low-pressure area at the nozzle outlet position, prompting the return ash in the riser 3 to smoothly fall to the bottom, and then being carried by the jet steam and blown into the furnace body 1 through the return pipe 4, realizing the return of the material in a good and stable circulating fluidized bed furnace body.

[0035] In addition, since the pneumatic active conveying return material method is adopted in this embodiment to replace the passive inclined pipe chute conveying method. Therefore, the return pipe 4 does not need to be inclined, but directly adopts a horizontal setting method, that is, it is perpendicular to the riser 3. In this way, the space occupied by the return pipe 4 in the height direction can be effectively reduced. At the same time, due to the existence of the low-pressure area, the height requirement of the material layer air seal in the riser 3 is reduced, and the height of the riser 3 can also be reduced, greatly reducing the height of the entire return material device, which is beneficial to reducing the equipment cost.

[0036] Preferably, the above-mentioned gas-solid separator 2 can be a cyclone separator, and the nozzle 5 is a Venturi nozzle. It should be noted that the cyclone separator and the Venturi nozzle in this embodiment can be purchased from the market, and their structures and working principles are prior arts, so they will not be elaborated here again.

[0037] Furthermore, the gas medium introduced into the nozzle 5 is steam or inert gas, and the local low pressure generated at the nozzle 5 outlet position is lower than 10 Kpa.

[0038] A return material device in this embodiment is provided with a nozzle 5 at the junction of the riser pipe 3 and the return material pipe 4. By means of jet steam from the nozzle, a stable pneumatic conveying return material cycle is formed in the return material pipe 4. Compared with the conventional passive inclined pipe chute feeding in the existing industry, it is changed to an active blowing method, making the return material more stable and controllable.

[0039] This embodiment also provides a coal gas generation system, which includes a furnace body 1 and a gas-solid separator 2 that are interconnected. Among them, the discharge end of the gas-solid separator 2 is connected to a riser pipe 3, and the riser pipe 3 is connected to a return material pipe 4 for communicating with the furnace body 1. A nozzle 5 is provided at the junction of the riser pipe 3 and the return material pipe 4, and the jet direction of the nozzle 5 faces the return material pipe 4, and at the same time, a local low pressure is generated at the gas outlet end of the nozzle 5.

[0040] Furthermore, the riser pipe 3 and the return material pipe 4 are perpendicularly intersecting. The nozzle 5 is a Venturi nozzle, and the local low pressure generated at the nozzle 5 is lower than 10 Kpa.

[0041] A coal gas generation system in this implementation is provided with a air distribution device 6 in the area near the lower part of the furnace body 1, and the air distribution device 6 is located below the interface of the return material pipe 4. The bottom of the furnace body 1 is fed with a gasifying agent into the air distribution device 6 as a fluidization and reaction medium, and the gasifying agent is a gas that can undergo a coal gasification reaction with the fuel.

[0042] Preferably, the above-mentioned gasifying agent is air, oxygen or steam; at the same time, the gas medium introduced into the nozzle 5 is steam or inert gas.

[0043] In a traditional coal gas generation system, since the pressure at the intersection of the return material inclined pipe and the coal gas generator is about 20 Kpa, in order to ensure smooth return of materials, the pressure of the return material steam introduced into the return feeder should be greater than 25 Kpa; at the same time, the return material steam is not allowed to enter the cyclone separator short-circuitly along the riser pipe. The equipment pressure of the cyclone separator is usually 10 Kpa, and the pressure difference with the return feeder is about 15 Kpa. According to the fluidization density of the return ash of the circulating fluidized bed coal gas generator is about 250 kg / m 3 , according to the formula P = ρgh, the theoretical required height h of the riser pipe is 6 m, and the riser pipe height in engineering applications is designed to be > 7 m. At the same time, the return feeder is connected to the coal gas generator through the return material inclined pipe. Due to the slope of the return ash chute, the return material inclined pipe usually has a length of 7 - 8 m. The total height requirement of these two parts is due to air sealing and the return ash chute, resulting in an increase of about 15 m in the low-performance height of the coal gas generator, ultimately leading to a significant increase in construction costs.

[0044] In the gas generation system of this embodiment, by introducing an appropriate amount of steam into the Venturi nozzle, according to the principle of Bernoulli's formula, when the outlet flow velocity of the Venturi nozzle reaches a certain speed, a local low pressure can be generated at this point; when the local low pressure near the outlet of the Venturi nozzle is lower than 10 Kpa, even if there is no return ash in the riser 3 to form a gas-sealing material layer, there will be no phenomenon of the jet steam rising upwards. Finally, the jet steam carrying the return ash separated by the cyclone separator enters the furnace body 1 along the return pipe 4 to participate in the gasification reaction. At the same time, since the material in the return pipe 4 is actively blown, the return pipe 4 does not need to be inclined, but can be directly arranged horizontally. Thus, it finally realizes the requirement for the installation height of the riser and the return inclined pipe required for traditional return, reduces the construction height of the gas generator and the whole, and greatly reduces the cost.

[0045] The above schematically describes the present invention and its implementation manners. This description is not restrictive, and only one of the implementation manners of the present invention is shown in the drawings. The actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative work without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A material return device, comprising a gas-solid separator (2), characterized in that: The discharge end of the gas-solid separator (2) is connected to a riser pipe (3), and the riser pipe (3) is connected to a return pipe (4) for communicating with the furnace body (1); The riser pipe (3) is arranged vertically, the return pipe (4) is arranged horizontally, and a nozzle (5) is provided at the junction of the riser pipe (3) and the return pipe (4); The blowing direction of the nozzle (5) faces the return pipe (4), and the nozzle (5) forms a stable pneumatic conveying return loop in the return pipe (4) by injecting a gas medium; at the same time, a local low pressure is generated in the area where the riser pipe (3) and the return pipe (4) meet, and the local low pressure generated at the outlet position of the nozzle (5) is lower than 10 Kpa.

2. The return material device according to claim 1, characterized in that: The nozzle (5) is a Venturi nozzle, and the gas-solid separator (2) is a cyclone separator.

3. The airlift device according to claim 2, characterized in that: The gas medium introduced into the nozzle (5) is steam or inert gas.

4. A gas generation system, comprising a furnace body (1) and a gas-solid separator (2) that are interconnected, characterized in that: The discharge end of the gas-solid separator (2) is connected to a riser pipe (3), and the riser pipe (3) is connected to a return pipe (4) for communicating with the furnace body (1); A nozzle (5) is provided at the junction of the riser pipe (3) and the return pipe (4), the blowing direction of the nozzle (5) faces the return pipe (4), and a local low pressure is generated at the gas outlet end of the nozzle (5); The riser pipe (3) and the return pipe (4) are perpendicularly intersected; The nozzle (5) is a Venturi nozzle, and the local low pressure generated at the nozzle (5) is lower than 10 Kpa.

5. A coal gas generation system according to claim 4, characterized in that: A air distribution device (6) is provided in the area near the lower part of the furnace body (1), and the air distribution device (6) is located below the interface of the return pipe (4).

6. The coal gas generating system according to claim 5, characterized in that: The bottom of the furnace body (1) is provided with a gasifying agent entering the air distribution device (6) as a fluidization and reaction medium, and the gasifying agent is a gas that can undergo a coal gasification reaction with the fuel.

7. A gas generation system according to claim 6, characterized in that: The gasifying agent is air, oxygen or steam; the gas medium introduced into the nozzle (5) is steam or inert gas.

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