A pyrolysis and supplementary combustion system and method for waste fan blades in coal-fired power plants

Abstract

The present invention relates to a pyrolysis and re-combustion system and method for waste fan blades based on coal-fired power plants, wherein the system includes a feeder, a crusher, a gas-liquid separation tower, a pyrolysis reactor, an oil storage tank, a gas storage tank, a flue gas mixing and temperature control device, a burner, and a waste bin. The present invention uses the flue gas at the outlet of the boiler reheater and the inlet of the economizer of the coal-fired power plant as the system startup and temperature control heat source, thereby realizing the temperature control of the pyrolysis reactor; the combustible gas generated by the pyrolysis of the fan blades is directly used for heating the pyrolysis reactor, thereby achieving energy-saving effects; the excess combustible gas is stored and used for re-combustion of the inlet flue of the SCR reactor during the peak-shaving process of the coal-fired unit, thereby avoiding the problem of catalyst channel blockage during the peak-shaving process; the oil substances generated by the pyrolysis of the fan blades are stored and put into the coal-fired boiler furnace for combustion during the peak-shaving process of the coal-fired unit, thereby stabilizing the boiler furnace combustion under low-load conditions, ensuring full utilization of the pyrolysis products, and realizing full recovery of energy.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler tail flue supplementary combustion, and in particular to a pyrolysis supplementary combustion system and method for waste fan blades based on a coal-fired power plant. Background Art

[0002] Wind energy is currently recognized as one of the clean energy sources in the world, but the treatment of wind energy equipment after scrapping is not always clean. Although most parts are recyclable, wind turbine blades are difficult to recycle effectively due to their composition. It is estimated that 10 kilograms of blade material is required for every 1kW of new installed capacity. Therefore, a 7.5MW wind turbine requires about 75 tons of blade material, which is a huge amount. Therefore, the recycling of retired blades will become an urgent problem that needs to be solved.

[0003] At present, most of the domestic coal-fired units are involved in peak load regulation, which makes the units often operate under low load conditions. When the boiler load decreases, the flue gas temperature at the inlet of the SCR reactor decreases accordingly. When the flue gas temperature is lower than the catalyst active reaction temperature (320-400°C), it is easy to cause the catalyst channel to be blocked, affecting the normal operation of the SCR. Coupled with increasingly stringent environmental protection requirements, it has become an inevitable requirement to operate the SCR normally under low load. In order to solve this problem, a boiler tail flue supplementary combustion solution is needed. Summary of the invention

[0004] The purpose of the present invention is to provide a waste fan blade pyrolysis and supplementary combustion system and method based on a coal-fired power plant, which pyrolyzes the waste fan blades and supplements them in the boiler tail flue to achieve the waste fan blade recycling and energy-saving effects.

[0005] The present invention provides a pyrolysis and re-combustion system for waste fan blades in coal-fired power plants, comprising a feeder, a crusher, a gas-liquid separation tower, a pyrolysis reactor, an oil storage tank, a gas storage tank, a flue gas mixing and temperature regulating device, a burner, and a waste bin;

[0006] The feeder outlet is connected to the crusher inlet, the crusher outlet is connected to the feed port of the pyrolysis reactor, the solid slag discharge port of the pyrolysis reactor is connected to the waste bin, the gaseous product discharge port of the pyrolysis reactor is connected to the feed port of the gas-liquid separation tower, the heating flue gas inlet of the pyrolysis reactor is connected to the flue gas mixing and temperature regulating device outlet and the burner outlet at the same time, the heating flue gas outlet of the pyrolysis reactor is connected to the boiler SCR reactor inlet flue, the gaseous product outlet of the gas-liquid separation tower is connected to the gas storage tank inlet through a one-way valve, and the liquid product outlet of the gas-liquid separation tower is connected to the oil storage tank inlet;

[0007] The two inlets of the flue gas mixing and temperature regulating device are respectively connected to the boiler SCR reactor inlet flue and the boiler reheater inlet flue through the first flow regulating valve and the second flow regulating valve;

[0008] The burner comprises a first burner outlet and a second burner outlet, wherein the first burner outlet is connected to the boiler SCR reactor inlet flue through a third flow regulating valve, and the second burner outlet is connected to the flue gas mixing and temperature regulating device outlet in parallel and then connected to the heating flue gas inlet of the pyrolysis reactor;

[0009] The gas storage tank outlet is connected to the burner inlet through a fifth flow regulating valve, and the burner inlet is connected to the boiler induced draft fan outlet pipeline through a fourth flow regulating valve connected in parallel with the fifth flow regulating valve;

[0010] The inlet of the gas-liquid separation tower is connected to the boiler induced draft fan outlet pipeline through the sixth flow regulating valve, and the outlet of the gas-liquid separation tower is connected to the boiler burner secondary air inlet pipeline through the seventh flow regulating valve;

[0011] The oil storage tank outlet is connected to the boiler burner oil nozzle through an eighth flow regulating valve.

[0012] The present invention also provides a supplementary combustion method of the above-mentioned waste fan blade pyrolysis supplementary combustion system based on a coal-fired power plant, comprising:

[0013] Before the system is started, all valves are closed. When the system starts, the first flow regulating valve and the second flow regulating valve are first opened, and the mixed flue gas temperature in the flue gas mixing and temperature regulating device is controlled within the range of 400-700°C by controlling the opening of the first flow regulating valve and the second flow regulating valve; when the temperature in the flue gas mixing and temperature regulating device is stable, the one-way valve, the feeder and the crusher are opened, and the pyrolysis reactor is waited to heat up to the set temperature; the set temperature is 350-650°C;

[0014] The initial feed amount of the feeder is controlled to be less than 20% of the designed feed amount, and when the temperature of the pyrolysis reactor is not stable at the set temperature, the material level in the pyrolysis reactor is controlled not to exceed half of the designed material level. If the material level in the pyrolysis reactor reaches half of the designed material level, the feeder is immediately turned off to stop feeding;

[0015] When the pyrolysis reactor reaches the set temperature, the feed rate of the feeder is gradually increased to the designed value, under the premise that the material level in the pyrolysis reactor does not exceed the designed material level and the average temperature in the pyrolysis reactor is within the set temperature fluctuation of no more than 10°C; when the feed rate, the temperature and material level in the pyrolysis reactor and the amount of gaseous products generated by the pyrolysis reaction are stable, the fifth flow regulating valve and the fourth flow regulating valve are opened and the burner is ignited, and as the smoke volume at the burner outlet gradually increases, the opening of the first flow regulating valve and the second flow regulating valve is gradually reduced, under the premise that the pyrolysis reactor is not lowered, until it is completely closed;

[0016] When the coal-fired boiler is operating at a load of more than 75%, part of the gaseous substances produced by the pyrolysis of the fan blades is used for the heat required for the pyrolysis itself, and the other part is stored in the gas storage tank, and the oil substances are stored in the oil storage tank; when the boiler undertakes the peak-shaving task, when the load is lower than 50%, the eighth flow regulating valve at the outlet of the oil storage tank is opened for stable combustion of the boiler furnace under low-load conditions, and the fifth flow regulating valve at the outlet of the gas storage tank is opened for supplementary combustion at the inlet flue of the boiler SCR reactor.

[0017] By means of the above scheme, the waste fan blade pyrolysis supplementary combustion system and method based on coal-fired power plants have the following technical effects:

[0018] 1. The flue gas at the outlet of the boiler reheater and the inlet of the economizer of the coal-fired power plant is used as the startup and temperature adjustment heat source of the system to achieve temperature control of the pyrolysis reactor.

[0019] 2. The combustible gas generated by the pyrolysis of the fan blades is directly used for heating the pyrolysis reactor, reducing the heat consumption of the system itself and achieving energy-saving effects.

[0020] 3. The excess combustible gas is stored and used for supplementary combustion in the flue gas inlet of the SCR reactor during the peak-shaving process of the coal-fired unit, which can avoid the problem of catalyst channel blockage in the peak-shaving process to a certain extent.

[0021] 4. The oil substances produced by the pyrolysis of the fan blades are stored and put into the coal-fired boiler furnace for combustion during the peak-shaving process of the coal-fired unit, so as to stabilize the boiler furnace combustion under low-load conditions, ensure the full utilization of the pyrolysis products, and realize full energy recovery.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the pyrolysis and supplementary combustion system of waste fan blades in a coal-fired power plant according to the present invention.

[0024] Numbers in the figure:

[0025] 1-feeder; 2-crusher; 3-gas-liquid separation tower; 4-pyrolysis reactor; 4.1-solid slag discharge port; 4.2-gas product discharge port; 4.31-heating flue gas inlet; 4.32-heating flue gas outlet; 5-oil storage tank; 6-gas storage tank; 7-flue gas mixing and temperature control device; 8-burner; 8.1-burner first outlet; 8.2-burner second outlet; 9.1-first flow control valve; 9.2-second flow control valve; 9. 3-third flow regulating valve; 9.4-fourth flow regulating valve; 9.5-fifth flow regulating valve; 9.6-sixth flow regulating valve; 9.7-seventh flow regulating valve; 9.8-eighth flow regulating valve; 10-waste bin; 11-check valve; P1-boiler SCR reactor inlet flue; P2-boiler reheater inlet flue; P3-boiler induced draft fan outlet pipeline; P4-boiler burner oil nozzle; P5-boiler burner secondary air inlet pipeline. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] Ginseng Figure 1 As shown, this embodiment provides a pyrolysis and re-combustion system for waste fan blades based on a coal-fired power plant, comprising a feeder 1, a crusher 2, a gas-liquid separation tower 3, a pyrolysis reactor 4, an oil storage tank 5, a gas storage tank 6, a flue gas mixing and temperature regulating device 7, a burner 8, and a waste bin 10;

[0028] The outlet of the feeder 1 is connected to the inlet of the crusher 2, the outlet of the crusher 2 is connected to the feed port of the pyrolysis reactor 4, the solid slag discharge port 4.1 of the pyrolysis reactor 4 is connected to the waste bin 10, the gaseous product discharge port 4.2 of the pyrolysis reactor 4 is connected to the feed port of the gas-liquid separation tower 3, the heating flue gas inlet 4.31 of the pyrolysis reactor 4 is simultaneously connected to the outlet of the flue gas mixing temperature regulating device 7 and the outlet of the burner 8, the heating flue gas outlet 4.32 of the pyrolysis reactor 4 is connected to the boiler SCR reactor inlet flue P1, the gaseous product outlet of the gas-liquid separation tower 3 is connected to the inlet of the gas storage tank 6 through the one-way valve 11, and the liquid product outlet of the gas-liquid separation tower 3 is connected to the inlet of the oil storage tank 5;

[0029] The two inlets of the flue gas mixing and temperature regulating device 7 are connected to the boiler SCR reactor inlet flue P1 and the boiler reheater inlet flue P2 respectively through the first flow regulating valve 9.1 and the second flow regulating valve 9.2;

[0030] The burner 8 comprises a first burner outlet 8.1 and a second burner outlet 8.2. The first burner outlet 8.1 is connected to the boiler SCR reactor inlet flue P1 through a third flow regulating valve 9.3. The second burner outlet 8.2 is connected in parallel to the outlet of the flue gas mixing and temperature regulating device 7 and then connected to the heating flue gas inlet 4.31 of the pyrolysis reactor 4.

[0031] The outlet of the gas storage tank 6 is connected to the inlet of the burner 8 through the fifth flow regulating valve 9.5, and the inlet of the burner 8 is connected to the boiler induced draft fan outlet pipeline P3 through the fourth flow regulating valve 9.4 connected in parallel with the fifth flow regulating valve 9.5;

[0032] The inlet of the gas-liquid separation tower 3 is connected to the boiler induced draft fan outlet pipeline P3 through the sixth flow regulating valve 9.6, and the outlet of the gas-liquid separation tower 3 is connected to the boiler burner secondary air inlet pipeline P5 through the seventh flow regulating valve 9.7. The air from the boiler induced draft fan outlet pipeline P3 enters the cooling device in the gas-liquid separation tower 3 through the sixth flow regulating valve 9.6 to be heated and then discharged into the boiler burner secondary air inlet pipeline P5 through the seventh flow regulating valve (9.7).

[0033] The outlet of the oil storage tank 5 is connected to the boiler burner nozzle P4 through the eighth flow regulating valve 9.8.

[0034] This embodiment also provides a post-combustion method for a waste fan blade pyrolysis post-combustion system, comprising:

[0035] Before the system is started, all valves are closed. When the system starts, the first flow regulating valve 9.1 and the second flow regulating valve 9.2 are opened first, and the mixed flue gas temperature in the flue gas mixing and temperature regulating device 7 is controlled within the range of 400-700°C by controlling the opening of the first flow regulating valve 9.1 and the second flow regulating valve 9.2; when the temperature in the flue gas mixing and temperature regulating device 7 is stable, the one-way valve 11, the feeder 1 and the crusher 2 are opened, and the pyrolysis reactor 4 is waited to heat up to the set temperature; the set temperature in this embodiment is 350-650°C;

[0036] The initial feeding amount of the feeder 1 is controlled to be less than 20% of the designed feeding amount, and when the temperature of the pyrolysis reactor 4 is not stable at the set temperature, the material level in the pyrolysis reactor 4 is controlled not to exceed half of the designed material level. If the material level in the pyrolysis reactor 4 reaches half of the designed material level, the feeder 1 is immediately closed to stop feeding;

[0037] When the pyrolysis reactor 4 reaches the set temperature, the feeding amount of the feeder 1 is gradually increased to the designed value, under the premise that the material level in the pyrolysis reactor 4 does not exceed the designed material level and the average temperature in the pyrolysis reactor 4 is within the set temperature fluctuation of no more than 10°C; when the feeding amount, the temperature, the material level in the pyrolysis reactor 4 and the amount of gaseous products generated by the pyrolysis reaction are stable, the fifth flow regulating valve 9.5 and the fourth flow regulating valve 9.4 are opened and the burner 8 is ignited. As the smoke volume at the burner 8 outlet gradually increases, under the premise that the pyrolysis reactor 4 is not reduced, the openings of the first flow regulating valve 9.1 and the second flow regulating valve 9.2 are gradually reduced until they are completely closed;

[0038] When the coal-fired boiler is operating at a load of more than 75%, part of the gaseous substances produced by the pyrolysis of the fan blades is used for the heat required for the pyrolysis itself, and the other part is stored in the gas storage tank 6, and the oil substances are stored in the oil storage tank 5; when the boiler undertakes the peak-shaving task, when the load is lower than 50%, the eighth flow regulating valve 9.8 at the outlet of the oil storage tank 5 is opened for stable combustion of the boiler furnace under low-load conditions, and the fifth flow regulating valve 9.5 at the outlet of the gas storage tank 6 is opened for supplementary combustion of the boiler SCR reactor inlet flue P1.

[0039] The pyrolysis and supplementary combustion system and method for waste fan blades in coal-fired power plants have the following technical effects:

[0040] 1. The flue gas at the outlet of the boiler reheater and the inlet of the economizer of the coal-fired power plant is used as the startup and temperature adjustment heat source of the system to achieve temperature control of the pyrolysis reactor.

[0041] 2. The combustible gas generated by the pyrolysis of the fan blades is directly used for heating the pyrolysis reactor, reducing the heat consumption of the system itself and achieving energy-saving effects.

[0042] 3. The excess combustible gas is stored and used for supplementary combustion in the flue gas inlet of the SCR reactor during the peak-shaving process of the coal-fired unit, which can avoid the problem of catalyst channel blockage in the peak-shaving process to a certain extent.

[0043] 4. The oil substances produced by the pyrolysis of the fan blades are stored and put into the coal-fired boiler furnace for combustion during the peak-shaving process of the coal-fired unit, so as to stabilize the boiler furnace combustion under low-load conditions, ensure the full utilization of the pyrolysis products, and realize full energy recovery.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A pyrolysis and supplementary combustion system for waste fan blades in coal-fired power plants, characterized in that: It comprises a feeder (1), a crusher (2), a gas-liquid separation tower (3), a pyrolysis reactor (4), an oil storage tank (5), a gas storage tank (6), a flue gas mixing and temperature regulating device (7), a burner (8), and a waste bin (10); The outlet of the feeder (1) is connected to the inlet of the crusher (2), the outlet of the crusher (2) is connected to the feed port of the pyrolysis reactor (4), the solid slag discharge port (4.1) of the pyrolysis reactor (4) is connected to the waste bin (10), the gaseous product discharge port (4.2) of the pyrolysis reactor (4) is connected to the feed port of the gas-liquid separation tower (3), the heating flue gas inlet (4.31) of the pyrolysis reactor (4) is simultaneously connected to the outlet of the flue gas mixing and temperature regulating device (7) and the outlet of the burner (8), the heating flue gas outlet (4.32) of the pyrolysis reactor (4) is connected to the inlet flue (P1) of the boiler SCR reactor, the gaseous product outlet of the gas-liquid separation tower (3) is connected to the inlet of the gas storage tank (6) through a one-way valve (11), and the liquid product outlet of the gas-liquid separation tower (3) is connected to the inlet of the oil storage tank (5); The two inlets of the flue gas mixing and temperature regulating device (7) are respectively connected to the boiler SCR reactor inlet flue (P1) and the boiler reheater inlet flue (P2) through a first flow regulating valve (9.1) and a second flow regulating valve (9.2); The burner (8) comprises a first burner outlet (8.1) and a second burner outlet (8.2); the first burner outlet (8.1) is connected to the boiler SCR reactor inlet flue (P1) via a third flow regulating valve (9.3); the second burner outlet (8.2) is connected in parallel to the outlet of the flue gas mixing and temperature regulating device (7) and then to the heating flue gas inlet (4.31) of the pyrolysis reactor (4); The outlet of the gas storage tank (6) is connected to the inlet of the burner (8) through a fifth flow regulating valve (9.5), and the inlet of the burner (8) is connected to the boiler induced draft fan outlet pipeline (P3) through a fourth flow regulating valve (9.4) connected in parallel with the fifth flow regulating valve (9.5); The inlet of the gas-liquid separation tower (3) is connected to the boiler induced draft fan outlet pipeline (P3) through the sixth flow regulating valve (9.6), and the outlet of the gas-liquid separation tower (3) is connected to the boiler burner secondary air inlet pipeline (P5) through the seventh flow regulating valve (9.7); The outlet of the oil storage tank (5) is connected to the oil nozzle (P4) of the boiler burner through an eighth flow regulating valve (9.8).

2. A supplementary combustion method for a pyrolysis supplementary combustion system of waste fan blades in a coal-fired power plant according to claim 1, characterized in that: include: Before the system is started, all valves are closed. When the system starts, the first flow regulating valve (9.1) and the second flow regulating valve (9.2) are first opened, and the mixed smoke temperature in the smoke mixing and temperature regulating device (7) is controlled within the range of 400-700° C. by controlling the opening of the first flow regulating valve (9.1) and the second flow regulating valve (9.2). When the temperature in the smoke mixing and temperature regulating device (7) is stabilized, the one-way valve (11), the feeder (1) and the crusher (2) are opened, and the pyrolysis reactor (4) is waited to be heated up to a set temperature; the set temperature is 350-650° C.; The feed amount of the feeder (1) is controlled to be less than 20% of the designed feed amount at the initial start-up, and when the temperature of the pyrolysis reactor (4) is not stabilized at the set temperature, the material level in the pyrolysis reactor (4) is controlled not to exceed half of the designed material level. If the material level in the pyrolysis reactor (4) reaches half of the designed material level, the feeder (1) is immediately closed to stop feeding; When the pyrolysis reactor (4) reaches the set temperature, the feed rate of the feeder (1) is gradually increased to the designed value, under the premise that the material level in the pyrolysis reactor (4) does not exceed the designed material level and the average temperature in the pyrolysis reactor (4) fluctuates within 10°C of the set temperature; when the feed rate, the temperature and material level in the pyrolysis reactor (4) and the amount of gaseous products generated by the pyrolysis reaction are stable, the fifth flow regulating valve (9.5) and the fourth flow regulating valve (9.4) are opened and the burner (8) is ignited; as the amount of smoke at the burner (8) outlet gradually increases, under the premise that the temperature of the pyrolysis reactor (4) does not decrease, the openings of the first flow regulating valve (9.1) and the second flow regulating valve (9.2) are gradually reduced until they are completely closed; When the coal-fired boiler is operated at a load of more than 75%, part of the gaseous substances generated by the pyrolysis of the fan blades is used for the heat required for the pyrolysis itself, and the other part is stored in the gas storage tank (6), and the oil substances are stored in the oil storage tank (5); when the boiler undertakes the peak load task, when the load is lower than 50%, the eighth flow regulating valve (9.8) at the outlet of the oil storage tank (5) is opened for stable combustion of the boiler furnace under low load conditions, and the fifth flow regulating valve (9.5) at the outlet of the gas storage tank (6) is opened for supplementary combustion of the inlet flue (P1) of the boiler SCR reactor.

Images