A fuel gasification system for lignite units

Abstract

The present invention discloses a fuel gasification system for a lignite unit, comprising a plurality of coal mills which are distributed and arranged, each of which is provided with a feed port; each of the coal mills is provided with a coal screener at its discharge port; a gasification system is arranged outside the coal mill, the gasification system is connected to each coal screener and is used to receive a ground lignite powder flow, the gasification system is connected to an air supply pipe and is used to transport pyrolysis gas; a separator is connected to one side of the gasification system and the separator separates carbon particles from the synthesis gas; a catalytic tank is connected outside the separator and the catalytic tank removes residual sulfide and chloride impurities in the synthesis gas through a catalyst; the gasification system of the present invention can promote uniform gasification reaction according to the mixing ratio of the lignite powder flow and the particle distribution through an air supply mechanism by combining central air supply with edge air supply, while ensuring that the best gasification effect can be achieved under different working conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of lignite pyrolysis and gasification equipment, in particular to a fuel gasification system for a lignite unit. Background Art

[0002] Thermal power plants are power facilities that use the heat released by the combustion of fossil fuels to generate electricity. With the gradual reduction of traditional high-grade coal resources and the enhancement of environmental protection awareness, the development and utilization of low-quality coal resources, such as lignite, has become an important way to meet the dual goals of energy demand and environmental protection. Lignite has a high water content, high volatile matter, low calorific value, and is flammable and explosive. The traditional direct combustion method is inefficient and polluting. Therefore, for lignite, efficient gasification technology can convert it into synthesis gas (mainly CO and H2), which not only improves energy utilization efficiency, but also effectively reduces pollutant emissions. At present, it is difficult for the existing gasification system to fully mix pyrolysis gas and lignite, resulting in reduced gasification efficiency, incomplete reaction, and unstable product quality.

[0003] Therefore, it is necessary to provide a fuel gasification system for a lignite unit to solve the problems raised in the above background technology. Summary of the invention

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a fuel gasification system for a lignite unit, comprising a coal mill, which is a plurality of coal mills arranged in a distributed manner, each of which is provided with a feed port, and a corresponding coal feeder is arranged outside the coal mill, and the coal feeder conveys lignite into the coal mill through the feed port; a coal screener is arranged at the discharge port of the coal mill, and the coal screener screens the ground lignite through a screen arranged inside the coal screener; a gasification system is arranged outside the coal mill, and the gasification system is connected to each coal screener for receiving a ground lignite powder flow, and a gas supply pipe is connected to the gasification system, and the gas supply pipe is used to convey pyrolysis gas, so that the lignite powder flow and the pyrolysis gas are gasified in the gasification system to obtain synthesis gas;

[0005] A separator is connected to one side of the gasification system, and the separator separates carbon particles from the synthesis gas. A catalytic tank is externally connected to the separator, and the catalytic tank removes residual sulfide and chloride impurities in the synthesis gas through a catalyst.

[0006] The gasification system comprises a gasification tank, a mixing bin is sealed inside the gasification tank, a plurality of powder channels are arranged on the side wall of the gasification tank, and each of the powder channels is connected to the mixing bin through an inner tube; a plurality of carbon powder nozzles are evenly arranged in the mixing bin; a pyrolysis gasification chamber is arranged below the mixing bin in the gasification tank, a partition seat is sealed below the mixing bin, a plurality of channels are arranged on the inner circumference of the partition seat, and the upper part of the channels are all connected to the mixing bin, so that the lignite powder in the mixing bin flows into the pyrolysis gasification chamber through the channels;

[0007] An air supply mechanism is arranged at the center of the gasification tank, and the air supply mechanism is connected to the air supply pipe. The air supply mechanism promotes uniform gasification reaction in the pyrolysis gasification chamber by combining central air supply and edge air supply according to the particle distribution of the lignite powder flow in the pyrolysis gasification chamber.

[0008] Furthermore, as a preference, each screen in the coal screener is connected to a screw conveying device, and the screw conveying device is connected to an airflow pipe, so that the lignite powder flow is conveyed to the gasification system along with the airflow;

[0009] The lignite powder flows with the same particle size in the screw conveying device enter the gasification system through the same powder channel.

[0010] Furthermore, preferably, a plurality of powder mixing plates are provided in the mixing bin, and the powder mixing plates fully mix the lignite powder flow through a plurality of mixing holes provided inside the powder mixing plates.

[0011] Further, as a preference, the gasification system further comprises a partition plate, which is vertically connected to the inner wall of the gasification tank, and a gas guide gap is formed between the partition plate and the gasification tank. A secondary pyrolysis tank is provided on one side of the gasification tank, and the secondary pyrolysis tank performs secondary pyrolysis on the synthesis gas formed by the preliminary pyrolysis of the lignite powder flow and the pyrolysis gas. An ash guide pipe is connected below the secondary pyrolysis tank, and a slag delivery channel is provided below the gasification tank.

[0012] A guide vane is rotatably arranged in the air guide gap.

[0013] Further, as a preference, the air delivery mechanism comprises an air delivery pipe, the upper end of the air delivery pipe is connected to the air supply pipe through a joint pipe, a straight pipe is connected to the center of the air delivery pipe, an air guide seat is fixed to the center of the partition seat, a double-channel pipe is rotatably connected to the air guide seat, two inner channels are arranged in the double-channel pipe, each of the inner channels is connected to the straight pipe and the air delivery pipe respectively; two air channels are correspondingly arranged in the air guide seat, and the air channels are sealed and connected to the inner channels;

[0014] A shunt pipe is vertically connected to the center below the partition seat, and one of the air passages is connected to the shunt pipe; an annular air cavity is also provided below the partition seat, and another of the air passages is connected to the annular air cavity;

[0015] The annular air cavity and the shunt pipe are respectively provided with micropores.

[0016] Further, as a preference, the straight tube is slidably connected in the air supply pipe, and the lower end of the straight tube is slidably sleeved with the dual-channel tube, a flow control ring is sleeved on the straight tube, a fixed ring is arranged in the air supply pipe, the cross section of the flow control ring is a trapezoidal structure, and the outer wall of the flow control ring is sealed and matched with the fixed ring;

[0017] A flow control shaft is fixed in the air supply pipe, one end of the flow control shaft penetrates into the straight pipe, and an arc-shaped notch which is sealed and matched with the flow control shaft is arranged in the straight pipe.

[0018] Furthermore, preferably, the straight pipe is slidably adjusted so that the pyrolysis gas transported in the air supply pipe and the straight pipe flows in corresponding proportions.

[0019] Furthermore, preferably, the upper ends of the two inner channels in the dual-channel tube are concentric structures, while the lower ends are symmetrically distributed on the left and right, and the two air channels in the air guide seat are distributed on the left and right. When one of the inner channels is connected to the air channel, the other inner channel is connected to the other air channel at the same time.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The gasification system provided in the present invention can promote uniform gasification reaction by combining central air supply and edge air supply through the air supply mechanism according to the mixing ratio of the lignite powder flow and the particle distribution, thereby avoiding local hypoxia or uneven temperature, improving the utilization efficiency of the entire reaction space, and accelerating the pyrolysis and gasification reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure of the gasification system in the present invention.

[0024] Figure 3 It is a structural schematic diagram of the air supply mechanism in the present invention.

[0025] Figure 4 for Figure 3 Enlarged schematic diagram at point A in the middle.

[0026] Figure 5 It is a schematic diagram of the structure of the powder mixing plate in the present invention.

[0027] In the figure: 1. coal mill; 11. coal screener; 12. air supply pipe; 13. separator; 14. catalytic tank; 15. screw conveyor; 2. gasification system; 21. gasification tank; 22. mixing bin; 23. powder channel; 24. inner pipe; 25. carbon powder nozzle; 26. partition seat; 27. channel; 28. auxiliary pyrolysis tank; 29. ​​ash guide pipe; 3. air supply mechanism; 31. air supply pipe; 32. straight pipe; 33. air guide seat; 34. double-channel pipe; 35. inner channel; 36. diverter pipe; 37. annular air cavity; 4. partition plate; 41. guide vane; 5. fixed ring; 51. flow control shaft; 6. powder leveling disk; 61. leveling hole. DETAILED DESCRIPTION

[0028] See also Figure 1-Figure 5 In an embodiment of the present invention, a fuel gasification system for a lignite unit includes a coal mill 1, which is a plurality of coal mills 1 arranged in a distributed manner. Each coal mill 1 is provided with a feed port, and a corresponding coal feeder is arranged outside the coal mill 1. The coal feeder conveys lignite into the coal mill 1 through the feed port; the coal mill 1 can grind the lignite through its internal crushing roller, and the discharge port of the coal mill 1 is provided with a coal screener 11. The coal screener 11 performs particle screening on the ground lignite through the screen arranged inside the coal mill 1; a gasification system 2 is arranged outside the coal mill 1, and the gasification system 2 is connected to each coal screener 11 for receiving the ground lignite The gasification system 2 is connected to a gas supply pipe 12, which is used to transport pyrolysis gas, so that the lignite powder flow and the pyrolysis gas are gasified in the gasification system 2 to obtain synthesis gas; a separator 13 is connected to one side of the gasification system 2, and the separator 13 separates carbon particles from the synthesis gas. The separator 13 is externally connected to a catalytic tank 14, and the catalytic tank 14 removes residual sulfide and chloride impurities in the synthesis gas through a catalyst; the purified synthesis gas can enter the turbine through an external pipeline, thereby impacting the blades and driving the rotor to rotate at a high speed; in this process, the thermal energy of the gas is converted into mechanical energy;

[0029] The gasification system 2 includes a gasification tank 21, a mixing bin 22 is sealed inside the gasification tank 21, a plurality of powder channels 23 are arranged on the side wall of the gasification tank 21, and each powder channel 23 is connected to the mixing bin 22 through an inner tube 24; a plurality of carbon powder nozzles 25 are evenly arranged in the mixing bin 22; a pyrolysis gasification chamber is arranged below the mixing bin 22 in the gasification tank 21, a partition seat 26 is sealed below the mixing bin 22, a plurality of channels 27 are arranged on the inner circumference of the partition seat 26, and the upper part of the channels 27 is connected to the mixing bin 22, so that the lignite powder in the mixing bin 22 enters the pyrolysis gasification chamber through the channels 27;

[0030] An air supply mechanism 3 is provided at the center of the gasification tank 21, and the air supply mechanism 3 is connected to the air supply pipe 12. The air supply mechanism 3 adopts a combination of central air supply and edge air supply in the pyrolysis gasification chamber according to the particle distribution of the lignite powder flow in the pyrolysis gasification chamber to promote the uniform gasification reaction. Among them, by monitoring the particle distribution of the lignite powder flow, the central air supply can ensure that the central area of ​​the gasification chamber obtains sufficient energy and reaction medium. At the same time, the edge air supply supplements the airflow around the cavity, avoids local hypoxia or uneven temperature, improves the utilization efficiency of the entire reaction space, and avoids the occurrence of overheating or cold spots. This is particularly important for controlling product quality and avoiding equipment damage. It can more effectively form a stirring effect on the lignite powder flow, so that the pyrolysis gas and the coal powder particles are fully contacted and mixed, accelerate the pyrolysis and gasification reaction process, and improve the reaction rate and conversion efficiency.

[0031] In this embodiment, a screw conveying device 15 is connected to each screen in the coal screener 11, and an air flow pipe is connected to the screw conveying device 15, so that the brown coal powder flow is transported to the gasification system 2 along with the air flow;

[0032] The lignite powder flows with the same particle size in the screw conveying device 15 enter the gasification system 2 through the same powder channel 23 , so that the lignite powder flows with different particle sizes can be mixed and proportioned in the mixing bin 22 .

[0033] As a preferred embodiment, a plurality of powder mixing plates 6 are provided in the mixing chamber 22 . The powder mixing plates 6 fully mix the lignite powder flow through a plurality of mixing holes 61 provided therein. Turbine blades may also be provided in the mixing chamber 22 .

[0034] In this embodiment, the gasification system 2 further includes a partition plate 4, which is vertically connected to the inner wall of the gasification tank 21, and a gas guide gap is formed between the partition plate 4 and the gasification tank 21. A secondary pyrolysis tank 28 is provided on one side of the gasification tank 21. The secondary pyrolysis tank 28 performs secondary pyrolysis on the synthesis gas formed by the preliminary pyrolysis of the lignite powder flow and the pyrolysis gas. An ash guide pipe 29 is connected below the secondary pyrolysis tank 28, and a slag delivery channel is provided below the gasification tank 21; the long-chain hydrocarbon compounds in the gas are further decomposed, the hydrogen ratio is increased, and the composition of the synthesis gas is optimized;

[0035] A guide vane 41 is rotatably arranged in the air guide gap to facilitate guiding the synthesis gas into the air guide gap.

[0036] In this embodiment, the air delivery mechanism 3 includes an air delivery pipe 31, the upper end of the air delivery pipe 31 is connected to the air supply pipe 12 through a joint pipe, a straight pipe 32 is connected to the center of the air delivery pipe 31, an air guide seat 33 is fixed to the center of the partition seat 26, a double-channel pipe 34 is rotatably connected to the air guide seat 33, two inner channels 35 are provided in the double-channel pipe 34, and each inner channel 35 is connected to the straight pipe 32 and the air delivery pipe 31 respectively; two air channels are correspondingly provided in the air guide seat 33, and the air channels are sealed and connected to the inner channels 35;

[0037] A shunt pipe 36 is vertically connected to the center below the partition seat 26, and one of the air passages is connected to the shunt pipe 36; an annular air cavity 37 is also provided below the partition seat 26, and another air passage is connected to the annular air cavity 37;

[0038] Micropores are provided on the annular air cavity 37 and the diverter pipe 36, respectively, that is, the pyrolysis gas can enter each inner channel 35 through the straight pipe 32 and the air supply pipe 31 respectively, and flow into the corresponding air channels. At this time, a part of the pyrolysis gas can form a central diffusion in the pyrolysis gasification cavity through the micropores on the diverter pipe 36, while the other part of the pyrolysis gas can form an edge distribution in the pyrolysis gasification cavity through the micropores on the annular air cavity 37, thereby fully supplying gas and mixing the lignite powder flow in the pyrolysis gasification cavity.

[0039] In this embodiment, the straight tube 32 is slidably connected in the air supply pipe 31, and the lower end of the straight tube 32 is slidably sleeved with the dual-channel tube 34. A flow control ring is sleeved on the straight tube 32, and a fixed ring 5 is arranged in the air supply pipe 31. The cross section of the flow control ring is a trapezoidal structure, and the outer wall of the flow control ring is sealed with the fixed ring 5.

[0040] A flow control shaft 51 is fixed in the air supply pipe 31 , one end of the flow control shaft 51 extends into the straight pipe 32 , and an arc-shaped notch that is sealed and matched with the flow control shaft 51 is provided in the straight pipe 32 .

[0041] As a preferred embodiment, the straight pipe 32 allows the pyrolysis gas transported in the air supply pipe 31 and the straight pipe 32 to flow in corresponding proportions during sliding adjustment, thereby strictly controlling the pyrolysis gas diffused in the center and the pyrolysis flow distributed at the edge.

[0042] In this embodiment, the upper ends of the two inner channels 35 in the dual-channel tube 34 are concentric structures, while the lower ends are symmetrically distributed on the left and right. The two air channels in the air guide seat 33 are distributed on the left and right. When one of the inner channels 35 is connected to the air channel, the other inner channel 35 is connected to the other air channel at the same time. In particular, during the rotation adjustment of the dual-channel tube 34, the pyrolysis gas in the air supply pipe 31 and the straight pipe 32 can switch and circulate between the annular air cavity 37 and the diverter pipe 36. On the one hand, the distribution of pyrolysis gas in the pyrolysis gasification cavity can be quickly adjusted, thereby providing appropriate pyrolysis gas transportation at different gasification stages (such as providing more concentrated pyrolysis gas in the early stage to promote rapid pyrolysis of lignite, and adjusting to a more uniform distribution in the later stage to maintain a stable gasification reaction). On the other hand, dynamic adjustment of the pyrolysis gas flow can effectively avoid local overheating or uneven temperature, maintain the thermodynamic balance of the entire gasification cavity, reduce incomplete pyrolysis or local sintering, improve the overall reaction efficiency and product quality of the system, ensure that the best gasification effect can be achieved under different working conditions, and enhance the versatility and market competitiveness of the device.

[0043] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A fuel gasification system for a lignite unit, characterized in that: The invention comprises a coal mill (1), which is a plurality of coal mills arranged in a distributed manner, each coal mill (1) being provided with a feed port, and a corresponding coal feeder being provided outside the coal mill (1), and the coal feeder conveys lignite into the coal mill (1) through the feed port; a coal screener (11) being provided at a discharge port of the coal mill (1), and the coal screener (11) is used to screen the ground lignite for particles through a screen provided inside the coal screener; a gasification system (2) being provided outside the coal mill (1), and the gasification system (2) being connected to each coal screener (11) and being used to receive a flow of ground lignite powder; and a gas supply pipe (12) being connected to the gasification system (2), and being used to convey pyrolysis gas, so that the lignite powder flow and the pyrolysis gas are gasified in the gasification system (2) to obtain synthesis gas; A separator (13) is connected to one side of the gasification system (2), and the separator (13) separates carbon particles from the synthesis gas. A catalytic tank (14) is externally connected to the separator (13), and the catalytic tank (14) removes residual sulfide and chloride impurities in the synthesis gas through a catalyst. The gasification system (2) comprises a gasification tank (21), wherein a mixing chamber (22) is sealedly provided inside the gasification tank (21), a plurality of powder channels (23) are provided on the side wall of the gasification tank (21), and each powder channel (23) is connected to the mixing chamber (22) through an inner tube (24); a plurality of carbon powder nozzles (25) are evenly arranged inside the mixing chamber (22); a pyrolysis gasification chamber is provided inside the gasification tank (21) below the mixing chamber (22), a partition seat (26) is sealedly provided below the mixing chamber (22), a plurality of channels (27) are provided on the inner circumference of the partition seat (26), and the upper parts of the channels (27) are connected to the mixing chamber (22), so that the brown coal powder in the mixing chamber (22) flows into the pyrolysis gasification chamber through the channels (27); An air supply mechanism (3) is provided at the center of the gasification tank (21), and the air supply mechanism (3) is connected to the air supply pipe (12). The air supply mechanism (3) promotes uniform gasification reaction in the pyrolysis gasification chamber by combining central air supply and edge air supply according to the particle distribution of the brown coal powder flow in the pyrolysis gasification chamber. The air supply mechanism (3) comprises an air supply pipe (31), the upper end of the air supply pipe (31) is connected to the air supply pipe (12) through a joint pipe, a straight pipe (32) is connected to the center of the air supply pipe (31), an air guide seat (33) is fixed to the center of the partition seat (26), a double-channel pipe (34) is rotatably connected to the air guide seat (33), two inner channels (35) are provided in the double-channel pipe (34), each inner channel (35) is connected to the straight pipe (32) and the air supply pipe (31) respectively; two air channels are correspondingly provided in the air guide seat (33), and the air channels are connected to the inner channels (35) in a sealed manner; A shunt pipe (36) is vertically connected to the center below the partition seat (26), wherein one of the air passages is in communication with the shunt pipe (36); an annular air cavity (37) is also provided below the partition seat (26), wherein another air passage is in communication with the annular air cavity (37); The annular air cavity (37) and the diverter pipe (36) are respectively provided with micropores; The straight tube (32) is slidably connected in the air supply tube (31), and the lower end of the straight tube (32) is slidably sleeved with the dual-channel tube (34). A flow control ring is sleeved on the straight tube (32), and a fixed ring (5) is arranged in the air supply tube (31). The cross section of the flow control ring is a trapezoidal structure, and the outer wall of the flow control ring is sealed and matched with the fixed ring (5); A flow control shaft (51) is fixed in the air supply pipe (31), one end of the flow control shaft (51) is inserted into the straight pipe (32), and an arc-shaped notch that is sealed and matched with the flow control shaft (51) is provided in the straight pipe (32); The straight pipe (32) is slidably adjusted so that the pyrolysis gas transported in the air supply pipe (31) and the straight pipe (32) can flow in corresponding proportions.

2. A fuel gasification system for a lignite unit according to claim 1, characterized in that: A screw conveying device (15) is connected to each screen in the coal screener (11), and an air flow pipe is connected to the screw conveying device (15), so that the brown coal powder flow is conveyed to the gasification system (2) along with the air flow; Brown coal powder flows with the same particle size in the screw conveying device (15) enter the gasification system (2) through the same powder channel (23).

3. The fuel gasification system for a lignite unit according to claim 1, characterized in that: A plurality of powder mixing plates (6) are arranged in the mixing bin (22), and the powder mixing plates (6) fully mix the lignite powder flow through a plurality of mixing holes (61) arranged inside the powder mixing plates (6).

4. The fuel gasification system for a lignite unit according to claim 1, characterized in that: The gasification system (2) further comprises a partition plate (4) vertically connected to the inner wall of the gasification tank (21), a gas guide gap being formed between the partition plate (4) and the gasification tank (21), a secondary pyrolysis tank (28) being provided on one side of the gasification tank (21), the secondary pyrolysis tank (28) performing secondary pyrolysis on the synthesis gas formed by the initial pyrolysis of the lignite powder flow and the pyrolysis gas, an ash guide pipe (29) being connected below the secondary pyrolysis tank (28), and a slag delivery channel being provided below the gasification tank (21); A guide blade (41) is rotatably arranged in the air guide gap.

5. The fuel gasification system for a lignite unit according to claim 1, characterized in that: The upper ends of the two inner channels (35) in the dual-channel tube (34) are in a concentric structure, while the lower ends thereof are symmetrically distributed left and right. The two air channels in the air guide seat (33) are distributed left and right. When one of the inner channels (35) is connected to an air channel, the other inner channel (35) is simultaneously connected to the other air channel.

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