A microwave-activated coke co-combustion denitrification device and method

Abstract

The invention discloses a device and method for denitrification by co-combustion of microwave-activated coke. The device includes a coal feeding hopper and a furnace. Coal is input onto a chain grate, and the coal cinder after combustion enters an ash hopper. The flue gas flows out through the outlet flue of the chain grate. The tail of the outlet flue of the chain grate is connected to the outlet flue of a dust collector, and a dust collector is arranged on the outlet flue of the dust collector. The tail of the outlet flue of the dust collector is respectively connected to a draft fan and a flue gas recirculation flue. Part of the flue gas flows out through the draft fan, and the other part of the flue gas enters the flue gas recirculation flue. A feeder on the flue gas recirculation flue inputs coke into the flue. The coke is mixed with the flue gas and then enters a microwave generator. The reacted coke is sprayed into the furnace through a coke spray gun. The ability of coke to reduce nitrogen oxides is improved by the microwave activation effect, and then the reacted coke is sprayed into the high-temperature and low-oxygen space in the furnace. While the coke is cyclically burned out, nitrogen oxides are also removed, and no secondary pollution to the environment will be caused.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation and emission reduction, and relates to a microwave-activated coke co-combustion denitrification device and method. Background Art

[0002] Industrial boilers mainly refer to steam boilers with a rated steam working pressure greater than 0.04 MPa and less than 3.8 MPa, and hot water boilers with a rated outlet water pressure greater than 0.1 MPa. The main problems existing in the development of the industrial boiler denitrification industry are that the number of industrial boilers is huge, the types are numerous, the single-unit scale is small, and the transformation and operation costs are expensive. At the same time, since most industrial boilers did not reserve a transformation space for NOx emission reduction during the initial construction, the development of NOx emission reduction technologies is relatively backward, and most industrial boilers are not equipped with denitrification equipment. Moreover, compared with coal-fired power station boilers, the NOx pollution problem of industrial boilers has not received enough attention. The current mainstream SCR and SNCR technologies are prone to cause secondary pollution and may lead to the blockage and corrosion of ABS in low-temperature equipment. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem that the existing SCR denitrification technology is prone to cause secondary pollution, and to provide a microwave-activated coke co-combustion denitrification device and method.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A microwave-activated coke co-combustion denitrification device includes a coal feeding hopper and a furnace. The furnace is divided into a flue gas area and a combustion area. Coal enters the combustion area through the coal feeding hopper and falls on the chain grate. The chain grate moves under the action of rollers. The bottom of the furnace is an ash hopper, and the coal cinder after coal combustion enters the ash hopper. After the flue gas enters the flue gas area, it flows out through the chain grate outlet flue. The tail of the chain grate outlet flue is connected to the dust collector outlet flue, and a dust collector is arranged on the dust collector outlet flue;

[0006] The tail of the dust collector outlet flue is respectively connected to an induced draft fan and a flue gas recirculation flue. Part of the flue gas flows out through the induced draft fan, and the other part of the flue gas enters the flue gas recirculation flue. A forced draft fan, a feeder and a microwave generator are sequentially arranged on the flue gas recirculation flue. The feeder inputs coke into the flue gas recirculation flue. After the coke is mixed with the flue gas, it enters the microwave generator. After being activated by microwave reaction, it is sprayed into the furnace through a coke spray gun arranged at the end of the flue gas recirculation flue.

[0007] A further improvement of the present invention is as follows:

[0008] A primary air chamber is arranged in the chain grate, and primary air is ejected from the primary air chamber to preheat the coal and provide oxygen for the coal.

[0009] In the combustion area of the furnace, a secondary air chamber is arranged, and secondary air is ejected from the secondary air chamber. The secondary air provides the air required for the combustion of volatile matter.

[0010] The coke spray guns are evenly distributed along the circumferential direction of the furnace, and there are 12 - 16 coke spray guns evenly distributed.

[0011] The temperature in the combustion area of the furnace is 1000 - 1300 °C, and the oxygen concentration is 0.5 - 3.5%.

[0012] A economizer is arranged in the outlet flue of the chain grate boiler, and the flue gas flows out after passing through the economizer.

[0013] An overfire air chamber is arranged in the flue area of the furnace, and overfire air is ejected from the overfire air chamber to enhance the flame fullness in the flue area.

[0014] A method for denitrification by microwave-activated coke co-combustion includes the following steps:

[0015] The coal feeder transports coal onto the chain grate. The coal enters the combustion area in the furnace and starts to burn as the chain grate moves. The burned coal cinder enters the ash hopper, and the flue gas enters the flue area.

[0016] After the flue gas enters the flue area, it flows out through the outlet flue of the chain grate boiler and passes through the economizer, dust collector, and the outlet flue of the dust collector in sequence.

[0017] A part of the flue gas in the outlet flue of the dust collector flows out through the induced draft fan, and the other part enters the flue gas recirculation flue.

[0018] The flue gas enters the flue gas recirculation flue, flows through the forced draft fan, and then mixes with the coke that enters the flue gas recirculation flue through the feeder. After the flue gas is mixed with the coke, it enters the microwave generator.

[0019] The coke is activated under the action of microwave in the microwave generator, and after activation, it is sprayed into the furnace through the coke spray gun.

[0020] The microwave power of the microwave generator during operation is 320 - 800 W.

[0021] The activation time of the flue gas and coke mixture in the microwave generator is 30 - 120 s.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a microwave-activated coke co-combustion denitrification device, which uses coke in the production process and improves the ability of coke to reduce nitrogen oxides through microwave activation. Then, the reacted coke is sprayed into the high-temperature and low-oxygen space in the furnace. While the coke is cyclically burned out, nitrogen oxides are also removed, without causing secondary pollution to the environment.

[0024] Furthermore, by arranging a primary air chamber in the chain grate, the preheating of coal can be achieved, and the oxygen required for coal combustion can be provided.

[0025] Furthermore, by arranging a secondary air chamber on the lower furnace, the air required for volatile combustion can be provided, thereby promoting the combustion of volatiles. At the same time, the air flow forms two swirls, strengthening the air flow disturbance and prolonging the residence time of the flue gas, making the combustion more complete. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a structural diagram of the microwave-activated coke co-combustion denitrification device of the present invention.

[0028] Wherein: 1 - coal hopper; 2 - chain grate; 3 - primary air chamber; 4 - ash hopper; 5 - roller; 6 - secondary air chamber; 7 - coke spray gun; 8 - burnout air chamber; 9 - furnace; 10 - chain furnace outlet flue; 11 - economizer; 12 - dust collector; 13 - dust collector outlet flue; 14 - induced draft fan; 15 - forced draft fan; 16 - feeder; 17 - microwave generator; 18 - flue gas recirculation flue. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Accordingly, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0031] It should be noted that like reference numerals and letters denote like items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

[0032] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is usually placed during use. This is only for the convenience of describing the present invention 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 thus should not be construed as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0033] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0034] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "coupled" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The present invention will be further described in detail below with reference to the drawings:

[0036] See Figure 1, which is the structural diagram of the microwave-activated coke co-combustion denitrification device in the present invention, includes a coal hopper 1, a chain grate 2, a primary air chamber 3, an ash hopper 4, rollers 5, a secondary air chamber 6, a coke lance 7, an overfire air chamber 8, a furnace 9, a flue gas outlet duct of the chain grate 10, a economizer 11, a dust collector 12, a dust collector outlet duct 13, an induced draft fan 14, a forced draft fan 15, a feeder 16, a microwave generator 17 and a flue gas recirculation duct 18; the furnace 9 is divided into a flue gas area and a combustion area, coal enters the combustion area through the coal hopper 1 and then falls on the chain grate 2, the chain grate 2 moves under the action of the rollers 5, a primary air chamber 3 is arranged in the chain grate 2, the primary air chamber 3 sprays primary air, the primary air preheats the coal and provides oxygen, a secondary air chamber 6 is arranged in the combustion area of the furnace 9, the secondary air chamber 6 sprays secondary air, the secondary air provides the air required for the combustion of volatile matter, the bottom of the furnace 9 is an ash hopper 4, the coal cinder after coal combustion enters the ash hopper 4, an overfire air chamber 8 is arranged in the flue gas area of the furnace 9, the overfire air chamber 8 sprays overfire air, which is used to increase the flame fullness in the flue gas area, after the flue gas enters the flue gas area, it flows out through the flue gas outlet duct of the chain grate 10, an economizer 11 is arranged in the flue gas outlet duct of the chain grate 10, and the flue gas flows out after passing through the economizer 11, the tail of the flue gas outlet duct of the chain grate 10 is connected to the dust collector outlet duct 13, and a dust collector 12 is arranged on the dust collector outlet duct 13; the tail of the dust collector outlet duct 13 is respectively connected to an induced draft fan 14 and a flue gas recirculation duct 18, part of the flue gas flows out through the induced draft fan 14, and the other part of the flue gas enters the flue gas recirculation duct 18, a forced draft fan 15, a feeder 16 and a microwave generator 17 are sequentially arranged on the flue gas recirculation duct 18, the feeder 16 inputs coke into the flue gas recirculation duct 18, the coke is mixed with the flue gas and then enters the microwave generator 17, after being activated by microwave reaction, it is sprayed into the furnace 9 through the coke lance 7 arranged at the end of the flue gas recirculation duct 18, the coke lances are evenly distributed along the circumference of the furnace, and there are 12-16 evenly distributed coke lances; the space in the furnace 9 is a high-temperature and low-oxygen space, where the temperature is 1000-1300 °C and the oxygen concentration is 0.5-3.5%.

[0037] Using the coke in the production process, the ability of the coke to reduce nitrogen oxides is improved by microwave activation, and then the reacted coke is sprayed into the high-temperature and low-oxygen space in the furnace. While the coke is cyclically burned out, nitrogen oxides are also removed, and no secondary pollution to the environment will be generated. And by arranging a primary air chamber in the chain grate, the coal can be preheated and the oxygen required for coal combustion can be provided. By arranging a secondary air chamber on the lower furnace, the air required for the combustion of volatile matter can be provided, thereby promoting the combustion of volatile matter. At the same time, the air flow forms two swirls, strengthening the air flow disturbance and prolonging the residence time of the flue gas, making the combustion more complete.

[0038] A method for denitrification by co - combustion of microwave - activated coke in the present invention specifically includes the following steps:

[0039] S1, The coal feeder 1 conveys coal to the chain grate 2. The coal enters the combustion area in the furnace 9 with the movement of the chain grate 2 and starts to burn. The coal cinder after combustion enters the ash hopper 4, and the flue gas enters the flue gas area;

[0040] S2, After the flue gas enters the flue gas area, it flows out through the flue of the chain grate outlet 10 and passes through the economizer 11, the dust collector 12, and the flue of the dust collector outlet 13 in sequence;

[0041] S3, A part of the flue gas in the flue of the dust collector outlet 13 flows out through the induced draft fan 14, and the other part enters the flue gas recirculation flue 18;

[0042] S4, The flue gas enters the flue gas recirculation flue 18, flows through the forced draft fan 15, and then mixes with the coke that enters the flue gas recirculation flue 18 through the feeder 16. After the flue gas is mixed with the coke, it enters the microwave generator 17. The microwave power of the microwave generator 17 during operation is 320 - 800W;

[0043] S5, The coke is activated by the action of microwaves in the microwave generator 17. The activation time is 30 - 120s. After activation, it is sprayed into the furnace 9 through the coke lance 7.

[0044] The specific working process of the present invention is as follows:

[0045] The coal falls from the coal feeder 1 onto the chain grate 2. The chain grate 2 moves forward driven by the roller 5. The coal cinder after combustion falls into the ash hopper 4. The primary air is ejected from the primary air chamber 3 to preheat the coal and provide the oxygen required for coal combustion. The furnace 9 is divided into upper and lower parts. The upper furnace is the flue gas area, and the lower furnace is the combustion area. The secondary air chamber 6 is arranged in the lower furnace. The secondary air chamber 6 mainly provides the air required for the combustion of volatile components, thereby promoting the combustion of volatile components. At the same time, the air flow forms two swirls, strengthening the air flow disturbance and prolonging the residence time of the flue gas, making the combustion more complete. The burnout air is ejected from the burnout air chamber 8, and its main function is to improve the fullness of the flame in the upper furnace and strengthen the mixing and disturbance of the flue gas and the burnout air, so that the fuel burns more fully. The flue gas after combustion flows out through the flue of the chain grate outlet 10 and enters the economizer 11, the dust collector 12, and the flue of the dust collector outlet 13 in sequence. Most of the flue gas in the flue of the dust collector outlet 13 flows out through the induced draft fan 14, and a small part of the flue gas enters the flue gas recirculation flue 18 and flows through the forced draft fan 15. The coke falls from the feeder 16 into the flue gas recirculation flue 18 and is sent into the microwave generator 17 together with the recirculated flue gas. The coke is activated under the action of microwaves and finally sprayed into the furnace 9 through the coke lance 7. While the coke is cycled and burned out, it also reduces NOx.

[0046] From the perspectives of source control, process control, circular economy and green emission reduction, the present invention collects the coke scattered during production, uses microwave activation to improve its ability to reduce NOx, and then sprays it into the high-temperature and low-oxygen space in the furnace. While the coke is cyclically burned out, NOx is also removed, providing a new method for the development of deep, efficient and low-nitrogen combustion technology. Moreover, the device adopted in the present invention has low transformation and operation costs, wide adaptability, no secondary pollution, no ammonia escape, and will not cause ABS blockage and corrosion of low-temperature equipment compared with the current mainstream SCR and SNCR technologies.

[0047] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A microwave-activated coke co-combustion denitrification device, characterized in that, it includes a coal feeding hopper (1) and a furnace (9). The furnace (9) is divided into a flue gas area and a combustion area. Coal enters the combustion area through the coal feeding hopper (1) and then falls on the chain grate (2). The chain grate (2) moves under the action of rollers (5). The bottom of the furnace (9) is an ash hopper (4). The coal cinder after coal combustion enters the ash hopper (4). After the flue gas enters the flue gas area, it flows out through the chain grate outlet flue (10). The tail of the chain grate outlet flue (10) is connected to the dust collector outlet flue (13), and a dust collector (12) is arranged on the dust collector outlet flue (13); the tail of the dust collector outlet flue (13) is respectively connected to a induced draft fan (14) and a flue gas recirculation flue (18). Part of the flue gas flows out through the induced draft fan (14), and another part of the flue gas enters the flue gas recirculation flue (18). A forced draft fan (15), a feeder (16) and a microwave generator (17) are sequentially arranged on the flue gas recirculation flue (18). The feeder (16) inputs coke into the flue gas recirculation flue (18). After the coke is mixed with the flue gas, it enters the microwave generator (17). After being activated by microwave reaction, it is sprayed into the furnace (9) through a coke spray gun (7) arranged at the end of the flue gas recirculation flue (18).

2. A microwave-activated coke co-combustion denitrification device according to claim 1, characterized in that, a primary air chamber (3) is arranged in the chain grate (2), and primary air is sprayed out from the primary air chamber (3). The primary air preheats the coal and provides oxygen.

3. A microwave-activated coke co-combustion denitrification device according to claim 1, characterized in that, a secondary air chamber (6) is arranged in the combustion area of the furnace (9), and secondary air is sprayed out from the secondary air chamber (6). The secondary air provides the air required for the combustion of volatile matter.

4. A microwave-activated coke co-combustion denitrification device according to claim 1, characterized in that, the coke spray guns (7) are evenly distributed along the circumferential direction of the furnace (9), and there are 12 - 16 coke spray guns (7) evenly distributed.

5. A microwave-activated coke co-combustion denitrification device according to claim 1, characterized in that, the temperature in the combustion area of the furnace (9) is 1000 - 1300 °C, and the oxygen concentration is 0.5 - 3.5%.

6. A microwave-activated coke co-combustion denitrification device according to claim 1, characterized in that, a economizer (11) is arranged in the chain grate outlet flue (10), and the flue gas flows out after passing through the economizer (11).

7. A microwave-activated coke co-combustion denitrification device according to claim 1, characterized in that, a burnout air chamber (8) is arranged in the flue gas area of the furnace (9), and burnout air is sprayed out from the burnout air chamber (8) to improve the flame fullness in the flue gas area.

8. A microwave-activated coke co-combustion denitrification method, characterized in that, it includes the following steps: The coal feeding hopper (1) conveys coal to the chain grate (2). The coal enters the combustion area in the furnace (9) as the chain grate (2) moves and starts to burn. The coal cinder after combustion enters the ash hopper (4), and the flue gas enters the flue gas area; After the flue gas enters the flue gas area, it flows out through the chain grate outlet flue (10) and passes through the economizer (11), the dust collector (12) and the dust collector outlet flue (13) in sequence; A part of the flue gas in the dust collector outlet flue (13) flows out through the induced draft fan (14), and another part enters the flue gas recirculation flue (18); The flue gas enters the flue gas recirculation flue (18), flows through the forced draft fan (15), and then mixes with the coke that enters the flue gas recirculation flue (18) through the feeder (16). After the flue gas is mixed with the coke, it enters the microwave generator (17); The coke is activated by the action of microwaves in the microwave generator (17), and after activation, it is sprayed into the furnace (9) through the coke spray gun (7).

9. A method for denitrification by co-combustion of microwave-activated coke as claimed in claim 8, characterized in that the microwave power of the microwave generator (17) during operation is 320 - 800 W.

10. A method for denitrification by co-combustion of microwave-activated coke as claimed in claim 8, characterized in that the activation time of the flue gas after being mixed with the coke in the microwave generator (17) is 30 - 120 s.

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