Gasification ash recovery system coupling boiler flue gas drying and premixing reburning

Abstract

The utility model discloses a gasification ash recovery system coupling boiler flue gas drying and premixing reburning, a solid outlet of an ash dryer is connected with a solid inlet of an ash storage system, a solid outlet of the ash storage system is connected with an inlet of a material mixing system, and an outlet of the material mixing system is connected with a solid inlet of a boiler combustion system. A flue gas outlet of the boiler combustion system is connected with a flue gas inlet of the dust-removing air-inducing system, a flue gas outlet of the dust-removing air-inducing system is connected with an inlet of the recycling flue gas purifying system, an outlet of the recycling flue gas purifying system is connected with a flue gas inlet of the ash drying machine, and a flue gas outlet of the ash drying machine is connected with the flue gas inlet of the dust-removing air-inducing system. The flue gas waste heat is used for heating and drying gasified ash solid, effective mixing and reburning of ash and raw coal are achieved, the gasified ash is effectively recycled, and the raw coal consumption of the boiler is reduced; flue gas is used as a drying medium, part of waste heat of flue gas discharged by the boiler is recycled, the temperature of the flue gas discharged by the boiler is reduced, and the efficiency of the boiler is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of recycling and utilization, and in particular relates to a gasification ash recovery system coupled with boiler flue gas drying and premixed reburning. Background Art

[0002] Both dry pulverized coal pressurized gasification process and wet pulverized coal pressurized gasification process are gasification process technologies that have been introduced more frequently by domestic coal chemical industry. In recent years, domestic gasification furnace technology has also developed rapidly. Among them, the technology level of pulverized coal gasification furnace has basically reached the international advanced level. It is the gasification technology that is currently promoted and applied more widely. The widespread application of pulverized coal gasification technology has played a major role in promoting the development of my country's coal chemical industry.

[0003] In pulverized coal gasification technology, the ash from the gasifier bottom is often transported to a slag dump for storage or landfill using methods such as quenching water baths, slag scooping machines, and filter presses. Alternatively, the gasification ash is prepared into a slurry and fed into a fluidized bed boiler for direct combustion. However, this technology suffers from less than ideal slurry transport and combustion reliability, and significantly impacts the on-site operating environment. Due to the high moisture content, low calorific value, fine particle size, and high viscosity of gasification ash, the ash after filter press is often not directly transported to a slag dump. Instead, it is piled in a slag dump and then transported to a landfill. Long-term storage not only occupies land but also easily generates dust pollution after the ash is dried. Furthermore, since gasification slag often contains a certain amount of unburned carbon residue, direct landfill or disposal wastes coal resources and is inconsistent with policies and guidelines for efficient and clean coal utilization. Summary of the Invention

[0004] The purpose of the utility model is to solve the above technical problems and provide a gasification ash recovery system coupled with boiler flue gas drying and premixed reburning, which saves coal resources and improves the effect of the boiler.

[0005] To achieve the above-mentioned objectives, the utility model provides a gasification ash recovery system coupled with boiler flue gas drying and premixed reburning, comprising an ash feeding system, an ash dryer, an ash storage system, a material blending system, a boiler combustion system, a dust removal and induced draft system and a recirculating flue gas system; the solid outlet of the ash feeding system is connected to the solid inlet of the ash dryer, the solid outlet of the ash dryer is connected to the solid inlet of the ash storage system, the solid outlet of the ash storage system is connected to the inlet of the material blending system, the outlet of the material blending system is connected to the solid inlet of the boiler combustion system, the flue gas outlet of the boiler combustion system is connected to the flue gas inlet of the dust removal and induced draft system, the flue gas outlet of the dust removal and induced draft system is connected to the inlet of the recirculating clean flue gas system, the outlet of the recirculating clean flue gas system is connected to the flue gas inlet of the ash dryer, and the flue gas outlet of the ash dryer is connected to the flue gas inlet of the dust removal and induced draft system.

[0006] Furthermore, the ash feeding system includes a slag feeding hopper and a screw feeder, and the slag feeding hopper is connected to the solid inlet of the ash dryer through the screw feeder.

[0007] Furthermore, the ash storage system includes a material storage bin and a metering feeder; the solid outlet of the ash dryer is connected to the solid inlet of the material storage bin, and the solid outlet of the material storage bin is connected to the material blending system through the metering feeder.

[0008] Furthermore, the material blending system includes a raw coal storage bin, a first-level belt weighing, a conveying and blending belt, a multi-stage transfer and re-mixing belt and a terminal unloading belt; the solid outlet of the material storage bin is connected to the conveying and blending belt through a metering feeder, and the raw coal storage bin is connected to the conveying and blending belt through a first-level belt weighing, and the conveying and blending belt is connected to the solid inlet of the boiler combustion system through a multi-stage transfer and re-mixing belt and a terminal unloading belt in turn.

[0009] Furthermore, the boiler combustion system includes a fuel system silo, a weighing feeder, a feeder outlet shut-off door, a combustion chamber body and a flue gas heat exchange area; the terminal unloading belt is connected to the solid inlet of the fuel system silo, the solid outlet of the fuel system silo is connected to the lower part of the combustion chamber body through the weighing feeder, the flue gas outlet on the upper part of the combustion chamber body is connected to the flue gas inlet of the flue gas heat exchange area, and the flue gas outlet of the flue gas heat exchange area is connected to the dust removal and ventilation system.

[0010] Furthermore, the dust removal and induced draft system includes a dust removal system and an exhaust fan. The flue gas outlet of the flue gas heat exchange zone is connected to the dust removal system. The dust removal system sends the clean flue gas to the post-processing system through the exhaust fan, and at the same time extracts a part of the hot flue gas through the recycled flue gas system into the flue gas inlet of the ash dryer. The flue gas outlet of the ash dryer sends the recycled dust-containing flue gas into the dust removal system.

[0011] Furthermore, a clean flue gas regulating valve is arranged between the recirculating flue gas system and the ash dryer.

[0012] Compared with the prior art, the present invention has the following beneficial effects: the present invention utilizes the flue gas waste heat of the boiler combustion system to heat and dry the gasified ash solids and realizes the effective mixing and reburning process of the ash and raw coal, effectively recovering the gasified ash, solving the problems of wasteful materials and environmental pollution caused by the stacking and landfilling of gasified ash, and saving the consumption of boiler raw coal; at the same time, the flue gas is used as a drying medium to simultaneously recover part of the waste heat of the boiler exhaust gas, thereby reducing the boiler exhaust temperature and improving the boiler efficiency;

[0013] At the same time, the present invention uses the hot flue gas of the boiler combustion system to dry the solid ash and realize the mixing process of the ash and raw coal. The system is relatively simple, saves coal resources, saves the investment cost and environmental problems of large-scale stacking and transportation of ash for landfill, and effectively treats and utilizes the gasified ash as a resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a flow chart of the utility model's coupled boiler flue gas drying and premixed reburning gasification ash recovery system;

[0015] Figure 2 for Figure 1 Schematic diagram of the specific structure. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning shown includes an ash feeding system 1, an ash dryer 2, an ash storage system 3, a material blending system 4, a boiler combustion system 5, a dust removal and induced draft system 6 and a recycled flue gas system 7. The solid outlet of the ash feeding system 1 is connected to the solid inlet of the ash dryer 2, the solid outlet of the ash dryer 2 is connected to the solid inlet of the ash storage system 3, the solid outlet of the ash storage system 3 is connected to the inlet of the material blending system 4, the outlet of the material blending system 4 is connected to the solid inlet of the boiler combustion system 5, the flue gas outlet of the boiler combustion system 5 is connected to the flue gas inlet of the dust removal and induced draft system 6, the flue gas outlet of the dust removal and induced draft system 6 is connected to the inlet of the recycled clean flue gas system 7, the outlet of the recycled clean flue gas system 7 is connected to the flue gas inlet of the ash dryer 2, and the flue gas outlet of the ash dryer 2 is connected to the flue gas inlet of the dust removal and induced draft system 6. After the gasified ash passes through the ash dryer 2, the dry ash is fed through the ash storage system 3 and the raw coal to achieve equal proportions of ash and raw coal. It is then evenly mixed through the material blending system 4 and sent to the boiler combustion system 5 for combustion. The raw flue gas at the flue gas outlet of the boiler combustion system 5 passes through the dust removal and induced draft system 6 to obtain clean flue gas and send it to the post-processing system. At the same time, a part of the hot flue gas is extracted and sent to the ash dryer 2 through the recycled flue gas system 7 and sent to the dust removal and induced draft system 6.

[0018] Combine Figure 2 The ash feeding system 1 shown includes a slag feeding hopper 1-1 and a screw feeder 1-2; the ash storage system 3 includes a material storage bin 3-1 and a metering feeder 3-2; the material blending system 4 includes a raw coal storage bin 4-1, a first-stage belt weighing 4-3, a conveying and blending belt 4-4, a multi-stage transfer and re-mixing belt 4-5, and a terminal unloading belt 4-2; the boiler combustion system 5 includes a fuel system silo 5-1, a weighing feeder 5-3, a feeder outlet shut-off door 5-4, a combustion chamber body 5-5, and a flue gas heat exchange area 5-2; the dust removal and induced draft system 6 includes a dust removal system 6-1 and an exhaust fan 6-2;

[0019] The slag feed hopper 1-1 is connected to the solid inlet of the ash dryer 2 through the screw feeder 1-2, the solid outlet of the ash dryer 2 is connected to the solid inlet of the material storage bin 3-1, the solid outlet of the material storage bin 3-1 is connected to the conveying and mixing belt 4-4 through the metering feeder 3-2, the raw coal storage bin 4-1 is connected to the conveying and mixing belt 4-4 through the first-level belt weighing 4-3, the conveying and mixing belt 4-4 is connected to the solid inlet of the fuel system silo 5-1 through the multi-stage transfer and mixing belt 4-5 and the terminal unloading belt 4-2, and the solid outlet of the fuel system silo 5-1 is connected to the weighing belt 4-3. The heavy feeder 5-3 is connected to the lower part of the combustion chamber body 5-5, and the flue gas outlet of the upper part of the combustion chamber body 5-5 is connected to the flue gas inlet of the flue gas heat exchange zone 5-2. The flue gas outlet of the flue gas heat exchange zone 5-2 is connected to the dust removal system 6-1. The dust removal system 6-1 sends the clean flue gas to the post-processing system through the exhaust fan 6-2, and at the same time extracts a part of the hot flue gas into the flue gas inlet of the ash dryer 2 through the recycling flue gas system 7. The flue gas outlet of the ash dryer 2 sends the recycled dust-containing flue gas into the dust removal system 6-1, and a clean flue gas regulating valve 7-2 is arranged between the recycling flue gas system 7 and the ash dryer 2.

[0020] The ash dryer 2 uses hot flue gas to directly dry the high-moisture ash, and the dried ash is sent to the ash storage system; the heat source for ash drying comes from the hot flue gas of the tail dust removal of the boiler combustion system 5. The hot flue gas is drawn out from the outlet flue of the dust removal and induced draft system, and after heating the dry ash in the ash dryer 2, it returns to the original flue gas dust removal inlet flue of the boiler combustion system 5.

[0021] When the gasification ash recovery system is working, the ash feeding system 1 continuously feeds solid ash with a moisture content of about 30% into the ash dryer 2. The hot flue gas from the recycled flue gas system 7 enters the ash dryer 2. The hot flue gas directly contacts and heats the ash. After heat exchange, the dust-laden flue gas returns from the recycled flue gas system 7 to the inlet of the dust removal and induced draft system 6. After heat exchange, the flue gas temperature drops from about 140°C to about 110°C, the ash temperature rises from room temperature to 80-100°C, and the ash moisture content drops to about 15%.

[0022] The ash solids discharged from the ash dryer 2 enter the ash storage system 3 for storage, and the stored ash is then sent to the material blending system 4 through the metering feeder. The raw coal is sent to the material blending system 4 through the first-level belt weighing 4-3, and the ash and raw coal are evenly mixed in the material blending system 4.

[0023] The solid material discharged from the material blending system 4 is sent to the boiler combustion system for combustion in the furnace to complete the reburning process of carbon-containing ash. The low-temperature flue gas after boiler heat exchange is sent to the dust removal and induced draft system 6 to complete the dust removal and pressure boosting process of the discharged flue gas and then sent for post-processing. A part of the hot flue gas is sent to the drying system through the recycled flue gas system 7 to complete the ash drying process.

[0024] When the drying equipment of the ash dryer 2 fails, the drying equipment and upstream systems can be stopped, the recirculating flue gas system can be closed, and the boiler can be completely switched to raw coal combustion without affecting the boiler operation.

Claims

1. A gasification ash recovery system coupled with boiler flue gas drying and premixed reburning, characterized by: The invention comprises an ash feeding system (1), an ash drying machine (2), an ash storage system (3), a material blending system (4), a boiler combustion system (5), a dust removal and ventilation system (6) and a recirculating flue gas system (7); the solid outlet of the ash feeding system (1) is connected to the solid inlet of the ash drying machine (2), the solid outlet of the ash drying machine (2) is connected to the solid inlet of the ash storage system (3), the solid outlet of the ash storage system (3) is connected to the inlet of the material blending system (4), the outlet of the material blending system (4) is connected to the solid inlet of the boiler combustion system (5), the flue gas outlet of the boiler combustion system (5) is connected to the flue gas inlet of the dust removal and ventilation system (6), the flue gas outlet of the dust removal and ventilation system (6) is connected to the inlet of the recirculating clean flue gas system (7), the outlet of the recirculating clean flue gas system (7) is connected to the flue gas inlet of the ash drying machine (2), and the flue gas outlet of the ash drying machine (2) is connected to the flue gas inlet of the dust removal and ventilation system (6).

2. The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning according to claim 1 is characterized in that: The ash feeding system (1) comprises a slag feeding hopper (1-1) and a screw feeder (1-2). The slag feeding hopper (1-1) is connected to the solid inlet of the ash dryer (2) via the screw feeder (1-2).

3. The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning according to claim 1 is characterized in that: The ash storage system (3) comprises a material storage bin (3-1) and a metering feeder (3-2); the solid outlet of the ash dryer (2) is connected to the solid inlet of the material storage bin (3-1), and the solid outlet of the material storage bin (3-1) is connected to the material blending system (4) via the metering feeder (3-2).

4. The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning according to claim 3 is characterized in that: The material blending system (4) comprises a raw coal storage bin (4-1), a first-stage belt weighing (4-3), a conveying and blending belt (4-4), a multi-stage transfer and re-mixing belt (4-5) and a terminal unloading belt (4-2); the solid outlet of the material storage bin (3-1) is connected to the conveying and blending belt (4-4) via a metering feeder (3-2), the raw coal storage bin (4-1) is connected to the conveying and blending belt (4-4) via a first-stage belt weighing (4-3), and the conveying and blending belt (4-4) is connected to the solid inlet of the boiler combustion system (5) via the multi-stage transfer and re-mixing belt (4-5) and the terminal unloading belt (4-2).

5. The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning according to claim 4 is characterized in that: The boiler combustion system (5) comprises a fuel system silo (5-1), a weighing feeder (5-3), a feeder outlet shut-off door (5-4), a combustion chamber body (5-5) and a flue gas heat exchange zone (5-2); a terminal unloading belt (4-2) is connected to the solid inlet of the fuel system silo (5-1), the solid outlet of the fuel system silo (5-1) is connected to the lower part of the combustion chamber body (5-5) through the weighing feeder (5-3), the flue gas outlet of the upper part of the combustion chamber body (5-5) is connected to the flue gas inlet of the flue gas heat exchange zone (5-2), and the flue gas outlet of the flue gas heat exchange zone (5-2) is connected to the dust removal and ventilation system (6).

6. The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning according to claim 5 is characterized in that: The dust removal and induced draft system (6) comprises a dust removal system (6-1) and an exhaust fan (6-2). The flue gas outlet of the flue gas heat exchange zone (5-2) is connected to the dust removal system (6-1). The dust removal system (6-1) sends the clean flue gas to the post-processing system through the exhaust fan (6-2), and at the same time extracts a portion of the hot flue gas through the recirculating flue gas system (7) to enter the flue gas inlet of the ash dryer (2). The flue gas outlet of the ash dryer (2) sends the recycled dust-containing flue gas into the dust removal system (6-1).

7. The gasification ash recovery system coupled with boiler flue gas drying and premixed reburning according to claim 1 is characterized in that: A clean flue gas regulating valve (7-2) is arranged between the recirculating flue gas system (7) and the ash dryer (2).

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