Equipment and process for coordinated disposal of multiple fuels in coal-fired power plants

Abstract

The invention discloses a device and process for the coordinated disposal of multiple fuels in a coal-fired power plant, including a power plant boiler, a high-temperature flue gas outlet is provided on the SCR reaction zone of the tail flue of the power plant boiler, the high-temperature flue gas outlet is connected to a rotary crushing device through a smoke dust separation device, the crushed material outlet of the rotary crushing device is connected to a drying straight pipe, the rotary crushing device is also provided with a wear-resistant material discharge port, the lower part of the drying straight pipe is connected to a medium-low moisture fuel bunker through a medium-low moisture fuel delivery device, the upper part of the drying straight pipe is connected to a high moisture fuel bunker through a high moisture fuel delivery device, the flue gas outlet at the top of the drying straight pipe is connected to a mechanical crushing device, the mechanical crushing device is connected to a low ignition point fuel bunker through a low ignition point fuel delivery device, and the outlet of the mechanical crushing device is connected to the boiler feed port of the power plant boiler. The invention can realize the synchronous clean incineration of sludge, biomass, domestic garbage, and industrial solid waste, simplify the process, and increase the adaptability of coal-fired power plant fuel.

Description

Technical Field

[0001] The present invention relates to the technical field of efficient coal combustion, and in particular to equipment and a process for coordinated disposal of multiple fuels in a coal-fired power plant. Background Art

[0002] At present, the coupled power generation technology routes of coal-fired power + biomass, coal-fired power + sludge, and coal-fired power + garbage are being promoted, striving to achieve clean disposal and recycling of urban, agricultural and forestry wastes through the high-temperature combustion system and flue gas purification system of coal-fired power plants. Although the blending process of coal-fired power + biomass and coal-fired power + sludge has become increasingly mature, the blending process of coal-fired power + garbage is still in the research and development stage. At the same time, the three types of blending processes are limited by differences in fuel characteristics, and the process characteristics and main equipment are different. Each type of blending process requires the establishment of a specific production line, the system is complex, and the total investment is high. Summary of the invention

[0003] The purpose of the present invention is to provide a device and process for the coordinated disposal of multiple fuels in a coal-fired power plant to solve the problems existing in the prior art. The present invention can realize the synchronous clean incineration disposal of sludge, biomass, domestic waste and industrial solid waste, simplify the process flow, save the overall project investment, reduce the system complexity, and increase the adaptability of coal-fired power plant fuel.

[0004] In order to achieve the above object, the present invention adopts the following technical scheme:

[0005] A device for coordinated disposal of multiple fuels in a coal-fired power plant comprises a power station boiler, wherein a high-temperature flue gas outlet is arranged on the SCR reaction zone of the tail flue of the power station boiler, the high-temperature flue gas outlet is connected to a rotary crushing device via a smoke dust separation device, the crushed material outlet of the rotary crushing device is connected to a drying straight pipe, the rotary crushing device is also provided with an abrasion-resistant material discharge port, the lower part of the drying straight pipe is connected to a medium-low moisture fuel bin via a medium-low moisture fuel conveying device, the upper part of the drying straight pipe is connected to a high moisture fuel bin via a high moisture fuel conveying device, the flue gas outlet at the top of the drying straight pipe is connected to a mechanical crushing device, the mechanical crushing device is connected to a low ignition point fuel bin via a low ignition point fuel conveying device, and the outlet of the mechanical crushing device is connected to the boiler feed port of the power station boiler.

[0006] Furthermore, a flue gas induced draft fan is provided between the top outlet of the drying straight tube and the mechanical crushing device, or between the outlet of the mechanical crushing device and the boiler feed inlet.

[0007] Furthermore, the pulverized material outlet of the rotary pulverizing device is connected to the bottom of the drying straight pipe.

[0008] Furthermore, the high-moisture fuel in the high-moisture fuel bin includes municipal sludge and industrial sludge.

[0009] Furthermore, the medium-low moisture fuel in the medium-low moisture fuel bin includes bagasse, industrial solid waste and dried and compressed domestic waste.

[0010] Furthermore, the low-ignition-point fuel in the low-ignition-point fuel bin is made of agricultural and forestry waste.

[0011] Furthermore, a primary gate cutting device is provided between the outlet of the high-moisture fuel delivery device and the inlet of the drying straight pipe.

[0012] Furthermore, an air locking structure is provided at the outlet of the mechanical crushing device.

[0013] Further, the wear-resistant material discharge port is connected to a medium- and low-moisture fuel delivery device.

[0014] A process for the coordinated disposal of multiple fuels in a coal-fired power plant, wherein high-temperature flue gas with a temperature of 350°C to 400°C is extracted from a high-temperature flue gas outlet, the high-temperature flue gas is dedusted by a smoke dust separation device, and then enters a drying straight pipe through a rotating crushing device. At the same time, the medium-low moisture fuel in a medium-low moisture fuel bin enters the drying straight pipe through a medium-low moisture fuel conveying device, and the high-moisture fuel in a high-moisture fuel bin enters the drying straight pipe through a high-moisture fuel conveying device. The medium-low moisture fuel and the high-moisture fuel are dried under the action of the high-temperature flue gas, and large particles of material directly fall into the rotating crushing device under the action of gravity, are carried by the flue gas for crushing, and are then sent back to the drying straight pipe. The flue gas at the outlet of the drying straight pipe has a temperature of 150 to 180°C, and enters the boiler feed port together with the low-ignition-point fuel crushed by a mechanical crushing device for cyclic re-combustion.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects:

[0016] When the present invention is in use, high-temperature flue gas with a temperature of 350°C to 400°C is extracted from the high-temperature flue gas outlet. The high-temperature flue gas enters the drying straight pipe through the rotating crushing device after dust removal by the smoke dust separation device. At the same time, medium-low moisture fuel enters the drying straight pipe through the medium-low moisture fuel conveying device, and high moisture fuel enters the drying straight pipe through the high moisture fuel conveying device. The medium-low moisture fuel and the high moisture fuel are dried under the action of the high-temperature flue gas, and large particles of materials directly fall into the rotating crushing device under the action of gravity, are carried by the flue gas for crushing, and are then sent back to the drying straight pipe again. The flue gas temperature at the outlet of the drying straight pipe is 150-180°C, and enters the boiler feed port together with the low ignition point fuel crushed by the mechanical crushing device for recycling and reburning, so as to realize the synchronous clean incineration and disposal of high moisture fuel, medium-low moisture fuel and low ignition point fuel, simplify the process flow, save the overall project investment, reduce the system complexity, and increase the adaptability of coal-fired power plant fuel. In addition, the present invention uses flue gas as a heat source and transmission medium, reduces the operating cost, and also has the flue gas recirculation low nitrogen transformation effect.

[0017] Specifically, the present invention can realize the simultaneous clean incineration disposal of sludge, biomass, domestic garbage and industrial solid waste.

[0018] Furthermore, by providing a primary gate cutting device, it is possible to prevent the high-moisture fuel from clogging the drying straight pipe due to excessive volume.

[0019] Furthermore, by providing an air lock structure at the outlet of the mechanical crushing device, it is possible to prevent smoke from flowing back into the mechanical crushing device, thereby wearing out the equipment and threatening operational safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the equipment and process for the coordinated disposal of multiple fuels in a coal-fired power plant according to the present invention.

[0021] Among them, 1 is a power station boiler, 2 is an SCR reaction zone, 3 is a smoke separation device, 4 is a rotary crushing device, 5 is a drying straight pipe, 6 is a high-moisture fuel bin, 7 is a high-moisture fuel conveying device, 8 is a medium-low moisture fuel bin, 9 is a medium-low moisture fuel conveying device, 10 is a flue gas induced draft fan, 11 is a low-ignition point fuel bin, 12 is a low-ignition point fuel conveying device, 13 is a mechanical crushing device, 14 is a boiler feed inlet, 15 is a primary gate cutting device, and 16 is a wear-resistant material discharge port. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0023] See also Figure 1 , a device for coordinated disposal of multiple fuels in a coal-fired power plant, comprising a power plant boiler 1, a high-temperature flue gas outlet is arranged on the SCR reaction zone 2 of the tail flue of the power plant boiler 1, the high-temperature flue gas outlet is connected to the rotary crushing device 4 through the smoke dust separation device 3, the crushed material outlet of the rotary crushing device 4 is connected to the drying straight pipe 5, the rotary crushing device 4 is also provided with an abrasion-resistant material discharge port 16, the lower part of the drying straight pipe 5 is connected to the medium-low moisture fuel bin 8 through the medium-low moisture fuel conveying device 9, the upper part of the drying straight pipe 5 is connected to the high-moisture fuel bin 6 through the high-moisture fuel conveying device 7, the flue gas outlet at the top of the drying straight pipe 5 is connected to the mechanical crushing device 13, the mechanical crushing device 13 is connected to the low-ignition-point fuel bin 11 through the low-ignition-point fuel conveying device 12, and the outlet of the mechanical crushing device 13 is connected to the boiler feed port 14 of the power plant boiler.

[0024] A flue gas induced draft fan 10 is arranged between the top outlet of the drying straight pipe 5 and the mechanical crushing device 13, or between the outlet of the mechanical crushing device 13 and the boiler feed port 14; the crushed material outlet of the rotary crushing device 4 is connected to the bottom of the drying straight pipe 5; the high-moisture fuel of the high-moisture fuel bin 6 includes municipal sludge and industrial sludge; the medium-low moisture fuel of the medium-low moisture fuel bin 8 includes bagasse, industrial solid waste and dried and compressed domestic waste; the low-ignition point fuel of the low-ignition point fuel bin 11 uses agricultural and forestry waste; a primary gate cutting device 15 is arranged between the outlet of the high-moisture fuel conveying device 7 and the inlet of the drying straight pipe 5; an air locking structure is arranged at the outlet of the mechanical crushing device 13; the wear-resistant material discharge port 16 is connected to the medium-low moisture fuel conveying device 9.

[0025] The present invention is further described in detail below in conjunction with specific embodiments:

[0026] 1. Extract medium and high temperature flue gas from the outlet of SCR reaction zone 2 of the tail flue of power plant boiler 1, and send the flue gas to rotary crushing device 4 through smoke dust separation device 3;

[0027] 2. The high-moisture fuel is delivered from the high-moisture fuel bin 6 to the drying straight pipe 5 through the high-moisture fuel delivery device 7;

[0028] 3. The medium and low moisture fuel is delivered from the medium and low moisture fuel bin 8 to the drying straight pipe 5 through the medium and low moisture fuel delivery device 9;

[0029] 4. The low-ignition-point fuel is fed from the low-ignition-point fuel bin 11 through the low-ignition-point fuel conveying device 12 into the mechanical crushing device 13;

[0030] 5. The flue gas carrying small particle fuel is discharged from the top of the drying straight pipe 5, and after passing through the induced draft fan 10, it carries the mechanically crushed low ignition point fuel and is finally sent to the boiler feed port 14 for recycling and re-combustion.

[0031] The step 1 specifically includes:

[0032] 1-1. To ensure the drying effect of the materials, the temperature of the extracted flue gas needs to be controlled in the range of 350℃~400℃. If the flue gas temperature cannot be guaranteed for some units, a small amount of flue gas can be extracted from the inlet of the upper heat exchanger for merging;

[0033] 1-2. The rotary crushing device 4 can be modified to some extent based on the original coal mill of the coal-fired power plant, such as a wind-type impact crusher, a wind-type hammer crusher, a fan coal mill or a similar simplified device;

[0034] 1-3. The material inlet of the rotary crushing device 4 is connected to the bottom of the drying straight pipe 5. Large particles of material can fall directly into the rotary crushing device 4 under the action of gravity, and are carried by the flue gas to be crushed and then sent back to the drying straight pipe 5.

[0035] The step 2 specifically includes:

[0036] 2-1. High-moisture fuel mainly refers to municipal sludge and industrial sludge, which generally have a moisture content of more than 70% and are very viscous, and cannot be directly fed into pulverized coal boilers for combustion;

[0037] 2-2. Since the drying straight pipe 5 is arranged vertically, the high-moisture fuel delivery device 7 can use a plunger pump or a special dragon pump. In order to prevent the mud from clogging the drying branch pipe due to excessive volume, a primary gate cutting device 15, such as a strip cutter, a gate cutter, etc., can be installed at the inlet;

[0038] 2-3. The wet sludge is initially dried and crushed by the hot flue gas during the falling process, and the generated fine dust particles are discharged from the top along with the flue gas, and the large particles of sludge fall into the rotating crushing device 4.

[0039] The step 3 specifically includes:

[0040] 3-1. Medium-low moisture fuel mainly refers to solid fuels with low viscosity such as bagasse, non-hazardous industrial solid waste, and dried and compressed domestic garbage, which can be directly fed into the bottom rotary crushing device 4;

[0041] 3-2. For medium and low moisture fuel delivery device 9, plunger pumps cannot be used. Scraper feeders, belt feeders or dragon conveyors should be used instead.

[0042] 3-3. The wear-resistant material discharge port 16 of the rotary crushing device 4 can be connected to the medium- and low-moisture fuel delivery device 9 to achieve cyclic crushing.

[0043] The step 4 specifically includes:

[0044] 4-1. Low-ignition-point fuels mainly refer to easily combustible agricultural and forestry wastes such as straw and wood, which have a high volatile content and a minimum volatile temperature of 200°C.

[0045] 4-2. The mechanical crushing device 13 generally adopts a winch structure, which can be divided into a single winch and a double winch. Some processes also use a roller coal mill. For pulverized coal boilers, if the biomass particles are too large after crushing, it may affect the combustion effect. Therefore, it is recommended that the biomass particle size does not exceed 8mm. For circulating fluidized bed boilers, the particle size should not exceed 100mm;

[0046] 4-3. An air locking structure shall be added at the connection between the mechanical crushing device 13 and the smoke pipe to prevent the smoke from flowing back into the crushing equipment, causing wear on the equipment and threatening the safe operation.

[0047] 4-4. The flue gas temperature at the outlet of the drying straight pipe 5 is 150-180°C, and the oxygen content is relatively low, which will not cause the low-ignition-point fuel to deflagrate.

[0048] The step 5 specifically includes:

[0049] 5-1. To ensure the stability of the system, the flue gas induced draft fan 10 needs to use wear-resistant and corrosion-resistant blades. To prevent straw and wood from getting stuck in the fan rotating structure after crushing, the flue gas induced draft fan 10 can be arranged before the mechanical crushing device. However, if the crushing performance is good and the fan structure is reasonable, it can also be arranged after the mechanical crushing device 13;

[0050] 5-2. Flue gas transports multiple fuels into the furnace for combustion. The boiler feed inlet 14 can be selected from the upper secondary air inlet, the limestone inlet in the furnace, the OFA air inlet, a newly added opening, etc.

[0051] When in use, high-temperature flue gas with a temperature of 350°C to 400°C is extracted from the high-temperature flue gas outlet. After dust removal by the smoke separation device 3, the high-temperature flue gas enters the drying straight pipe 5 through the rotating crushing device 4. At the same time, the medium-low moisture fuel in the medium-low moisture fuel bin 8 enters the drying straight pipe 5 through the medium-low moisture fuel conveying device 9, and the high-moisture fuel in the high-moisture fuel bin 6 enters the drying straight pipe 5 through the high-moisture fuel conveying device 7. The medium-low moisture fuel and the high-moisture fuel are dried under the action of the high-temperature flue gas, and large particles of material fall directly into the rotating crushing device 4 under the action of gravity, are carried by the flue gas for crushing, and are then sent back to the drying straight pipe 5. The flue gas temperature at the outlet of the drying straight pipe 5 is 150-180°C, and enters the boiler feed port 14 together with the low-ignition point fuel crushed by the mechanical crushing device 13 for cyclic reburning.

Claims

1. A device for the coordinated disposal of multiple fuels in a coal-fired power plant, characterized in that: The utility boiler (1) comprises a high-temperature flue gas outlet provided on the SCR reaction zone (2) of the tail flue of the utility boiler (1), the high-temperature flue gas outlet being connected to a rotary crushing device (4) through a smoke dust separation device (3), the crushed material outlet of the rotary crushing device (4) being connected to a drying straight pipe (5), the rotary crushing device (4) being further provided with an abrasion-resistant material discharge port (16), the lower part of the drying straight pipe (5) being connected to a medium-low moisture fuel bin (8) through a medium-low moisture fuel conveying device (9), the upper part of the drying straight pipe (5) being connected to a high moisture fuel bin (6) through a high moisture fuel conveying device (7), the flue gas outlet at the top of the drying straight pipe (5) being connected to a mechanical crushing device (13), the mechanical crushing device (13) being connected to a low ignition point fuel bin (11) through a low ignition point fuel conveying device (12), the outlet of the mechanical crushing device (13) being connected to a boiler feed port (14) of the utility boiler; A flue gas induced draft fan (10) is provided between the top outlet of the drying straight tube (5) and the mechanical crushing device (13), or between the outlet of the mechanical crushing device (13) and the boiler feed inlet (14); The pulverized material outlet of the rotary pulverizing device (4) is connected to the bottom of the drying straight pipe (5).

2. The equipment for co-processing multiple fuels in coal-fired power plants according to claim 1, characterized in that: The high-moisture fuel in the high-moisture fuel bin (6) includes municipal sludge and industrial sludge.

3. The equipment for co-processing multiple fuels in coal-fired power plants according to claim 1, characterized in that: The medium-low moisture fuel in the medium-low moisture fuel bin (8) includes bagasse, industrial solid waste and dried and compressed domestic waste.

4. The equipment for co-processing multiple fuels in a coal-fired power plant according to claim 1, characterized in that: The low-ignition-point fuel in the low-ignition-point fuel bin (11) is agricultural and forestry waste.

5. The equipment for co-processing multiple fuels in a coal-fired power plant according to claim 1, characterized in that: A primary cut-off device (15) is provided between the outlet of the high-moisture fuel delivery device (7) and the inlet of the drying straight pipe (5).

6. The equipment for co-processing multiple fuels in a coal-fired power plant according to claim 1, characterized in that: An air locking structure is provided at the outlet of the mechanical crushing device (13).

7. The equipment for co-processing multiple fuels in a coal-fired power plant according to claim 1, characterized in that: The wear-resistant material discharge port (16) is connected to a medium-low moisture fuel delivery device (9).

8. A process for the coordinated disposal of multiple fuels in a coal-fired power plant, using the equipment for the coordinated disposal of multiple fuels in a coal-fired power plant as claimed in any one of claims 1 to 7, characterized in that: High-temperature flue gas with a temperature of 350°C to 400°C is extracted from the high-temperature flue gas outlet. After dust removal by a flue gas separation device (3), the high-temperature flue gas enters a drying straight pipe (5) through a rotary crushing device (4). At the same time, the medium-low moisture fuel in the medium-low moisture fuel bin (8) enters the drying straight pipe (5) through a medium-low moisture fuel conveying device (9), and the high-moisture fuel in the high-moisture fuel bin (6) enters the drying straight pipe (5) through a high-moisture fuel conveying device (7). The medium-low moisture fuel and the high-moisture fuel are dried under the action of the high-temperature flue gas. Large particles of material fall directly into the rotary crushing device (4) under the action of gravity, are carried by the flue gas for crushing, and are then sent back to the drying straight pipe (5). The flue gas at the outlet of the drying straight pipe (5) has a temperature of 150 to 180°C and enters the boiler feed port (14) together with the low ignition point fuel crushed by the mechanical crushing device (13) for cyclic re-combustion.

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