A structure for preventing smoke from flowing downward at a slagging port of a scraper of a waste heat boiler

Abstract

The utility model discloses a structure is prevented that flue gas under the chase of waste ash port of waste heat boiler scraper, including waste heat boiler radiation area, waste heat boiler convection area, radiation area scraper, convection area scraper, convection area ash pipeline, convection area flue dust enters the crusher inlet pipeline and radiation area ash pipeline, the intercommunication of convection area scraper ash pipeline and convection area flue dust enters the crusher inlet pipeline is cut off state, and is provided with detachable flange short section at cut -off position, detachable flange short section top and convection area scraper ash pipeline pass through flange bolt connection, and detachable flange short section below and convection area flue dust enters the 10mm gap of crusher inlet pipeline between, and the same size flange of detachable flange short section is installed to convection area flue dust enters the crusher inlet pipeline close short section, and installs fluorocarbon color steel sheet of delta = 0.8mm in gap. The labor intensity of staff is reduced greatly, and the maintenance cost brought by frequent dismounting dredging of system is reduced.

Description

Technical Field

[0001] This utility model pertains to flue gas conveying systems, specifically relating to a structure for preventing flue gas from flowing downwards from the ash outlet of a waste heat boiler scraper conveyor. Background Technology

[0002] Side-blown smelting furnaces, as a new type of furnace in the nickel smelting industry, have replaced reverberatory furnaces in the production of nickel anode plates. However, in actual operation, the side-blown furnace smelting process cannot meet the micro-negative pressure operation requirements of the subsequent flue gas treatment system. This is most evident in the waste heat boiler system at the flue outlet of the side-blown furnace. During operation, the inlet pressure of the waste heat boiler furnace is usually below 80 Pa, and the outlet pressure is around 40 Pa. The flue gas flows towards the boiler outlet under positive pressure conditions in the furnace. To increase the heat exchange area in the furnace, the waste heat boiler is usually designed and installed with heat exchange surfaces perpendicular to the flue gas flow direction, such as tube screens, tube bundles, and flue gas baffles, in the radiation and convection zones. These heat exchange surfaces not only optimize the dynamic field of the flue gas, but also have a certain dust collection effect because they are perpendicular to the flue gas flow direction. The soot falling below the boiler is collected and transported by a submerged scraper ash remover. A crusher installed on the outlet channel of the submerged scraper ash remover crushes coke lumps and large particles of soot before they fall into the soot collection bin below. During soot transport, the bin pump installed below the soot collection bin achieves equal flow rate transport of soot by opening and closing the inlet valve. The prolonged positive pressure flue gas conditions in the boiler furnace cause some flue gas to enter the submerged scraper ash remover and then enter the crusher and soot collection bin along the outlet pipe. The water vapor in the sulfur dioxide-containing flue gas that diffuses into the crusher and soot collection bin will condense into acid water. The acid water will cover the inner surface of the equipment and mix with the soot, frequently causing soot to be unable to be transported normally or to block the outlet pipe of the bin pump. It is necessary to frequently disassemble the equipment and pipes for unblocking and cleaning of soot, which greatly increases the labor intensity, interrupts the soot transport process, and the long-term immersion of the equipment in acid water will cause corrosion, shorten the service life of the equipment, and greatly increase the operating cost of the system. Utility Model Content

[0003] The purpose of this invention is to solve the problems existing in the current process flow and to provide a structure that prevents flue gas from flowing downwards from the ash outlet of the waste heat boiler scraper conveyor, thereby improving the service life of the equipment, reducing labor intensity, and reducing the operating cost of the system.

[0004] To achieve the above objectives, this utility model adopts the following technical solution: a method and device for preventing flue gas from flowing downwards and causing damp ash at the ash outlet of a waste heat boiler scraper conveyor. The waste heat boiler is a horizontal waste heat boiler used for flue gas treatment in a side-blown furnace process system in the nickel smelting industry. During production, to ensure the metallurgical furnace process conditions, the boiler inlet negative pressure is controlled below 80 Pa. The furnace of the waste heat boiler is divided into a radiation zone and a convection zone according to the main heat transfer mode. The radiation zone is designed with flue gas baffles and radiation tube screens, and the convection zone is designed with slag-condensing tube screens and convection tube bundles. The flue gas baffles, tube screens, and tube bundles in the above design are perpendicular to the flue gas movement direction, mainly used to increase the heat exchange area of ​​the furnace and optimize the flue gas movement field. Submerged scrapers are installed below the radiation zone and the convection zone, respectively. The plate dust collector is used for collecting and transporting flue dust. The scraper conveyors in the radiation zone and convection zone move in opposite directions. The flue dust collected and transported by the scraper conveyors falls into the crusher installed below. The crushed coke and flue dust fall into the intermediate silo installed below the crusher at the crusher outlet. The flue dust collected by the scraper conveyor in the radiation zone falls directly into the crusher, while the flue dust collected by the scraper conveyor in the convection zone falls into the scraper conveyor's ash discharge pipe. After passing through a detachable flanged short section, the flue dust in the convection zone enters the crusher's inlet pipe and enters the crusher. The crushed coke and large pieces of flue dust fall into the intermediate silo installed below the crusher. The intermediate silo is installed above the bottom-type silo pump. The intermediate silo and the silo pump are connected by a pipe. A pneumatic disc valve is installed on the connecting pipe. The silo pump uses compressed air to transport materials. This includes the waste heat boiler radiant zone, waste heat boiler convection zone, radiant zone scraper conveyor, convection zone scraper conveyor, convection zone ash discharge pipe, convection zone flue ash inlet pipe into crusher, and radiant zone ash discharge pipe. The connection between the ash discharge pipe of the convection zone scraper conveyor and the inlet pipe of the convection zone flue gas into the crusher is cut off. A detachable flanged short section is installed at the cut-off position. The upper part of the detachable flanged short section is connected to the ash discharge pipe of the convection zone scraper conveyor by flange bolts. A 10mm gap is left between the lower part of the detachable flanged short section and the inlet pipe of the convection zone flue gas into the crusher. A flange of the same size as the detachable flanged short section is installed near the short section of the inlet pipe of the convection zone flue gas into the crusher. A fluorocarbon color steel plate with δ=0.8mm is installed in the gap. The detachable flanged short section and the upper flange of the convection zone flue gas entering the crusher inlet pipe are equipped with bolts of 35mm length on the lower flange face, and the bolt tightening distance is 25mm.

[0005] Furthermore, the ash is intermittently conveyed in the radiation and convection zones, and the scraper conveyor is intermittently started and stopped during ash delivery.

[0006] Furthermore, both the detachable flanged short section and the ash discharge pipe of the convection zone scraper conveyor are square pipes with the same dimensions, 500mm×500mm.

[0007] Furthermore, the detachable flanged short section and the ash discharge pipe connection of the convection zone scraper conveyor are fully secured with bolts.

[0008] Furthermore, a 10mm gap is left between the detachable flanged short section and the convective zone flue gas inlet pipe of the crusher. The connection between the convective zone flue gas inlet pipe of the crusher and the detachable flanged short section is fitted with flanges of the same specifications. Bolts and nuts with a length of 35mm are installed at the lower end of the flange, and the nut tightening length is 25mm. The remaining 3 flanges are not fitted with bolts. When ash feeding stops, a δ=0.8mm fluorocarbon color steel plate is installed in the gap. The fluorocarbon color steel plate is tightly attached to the detachable flanged short section, and 8×8mm packing is used to wrap around the bottom of the fluorocarbon color steel plate. When the flue gas dissipates downward, the color steel plate blocks the flue gas from dissipating downward, and the condensed acid water in the flue gas flows out through the gap above the color steel plate.

[0009] Furthermore, when feeding ash, remove the packing and the fluorocarbon color steel plate. Use 10×10mm packing to wrap around the detachable flanged short section flange to seal the gap in the pipeline.

[0010] Furthermore, a 400mm×400mm square opening is made below the inlet pipe of the crusher where the flue dust from the convection zone enters. The square opening is vertically connected to a 400mm×400mm inclined chute. A 400mm×400mm detachable manhole is made on the inclined chute 800mm from the square opening. The inclined chute changes direction vertically downwards 1000mm from the square opening. A 400mm×400mm gate valve is installed on the vertically downward pipe.

[0011] Furthermore, during ash feeding, the convection zone scraper conveyor is started intermittently, and the removable manhole on the inclined chute is opened. When the scraper conveyor is started, the removable manhole is opened to observe the accumulated water, wet ash, and damp ash falling into the inclined chute. When all the falling ash is dry ash, the removable manhole is closed, and the scraper conveyor is started continuously. At this time, some of the dry ash completely fills the inclined chute, and the remaining dry ash falls into the crusher, completing the ash feeding process.

[0012] Furthermore, after the ash delivery is completed, the gate valve is opened to drain the accumulated water and damp ash through the pipe into the mobile ash-hauling vehicle below.

[0013] Furthermore, when the ash discharge pipe of the scraper conveyor in the convection zone is blocked, the detachable flanged short section is removed for manual unblocking.

[0014] This utility model offers the following advantages over existing processes: A method and device for preventing damp ash from escaping due to flue gas seepage at the ash discharge port of a waste heat boiler scraper conveyor. When not discharging ash, a color steel plate blocks the escape of flue gas towards the equipment below, and condensed acid water in the flue gas flows out through gaps in the top of the color steel plate. During ash discharging, the scraper conveyor is jogged, and personnel observe through the detachable manhole to convey the accumulated water and damp ash into the inclined chute for storage. Dry ash completes the subsequent ash discharging process. This ash discharging method and device effectively solves the problems of damp ash accumulation, internal water accumulation, equipment corrosion, and equipment and pipeline blockage caused by flue gas escaping into the crusher, intermediate silo, and silo pump, and significantly reduces the labor intensity of workers. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram showing the location of the inclined chute and the convection zone flue ash entering the crusher inlet pipe of this utility model; Figure 3 This is a schematic diagram of the detachable flanged short section of this utility model; In the diagram: 1. Waste heat boiler radiant zone; 2. Waste heat boiler convection zone; 3. Convection zone scraper conveyor; 4. Radiant zone scraper conveyor; 5. Convection zone scraper conveyor ash discharge pipe; 6. Detachable flanged short section; 7. Detachable manhole; 8. Inclined chute; 9. Gate valve; 10. Ground-mounted ash pipe; 11. Convection zone ash inlet pipe to crusher; 12. Radiant zone scraper conveyor ash discharge pipe; 13. Crusher; 14. Intermediate silo; 15. Pneumatic disc valve; 16. Disc feeder; 17. Silo pump outlet pipe; 18. Metallurgical furnace outlet flue; 19. Gap between the detachable flanged short section and the convection zone ash inlet pipe to crusher. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: like Figure 1 As shown, a structure for preventing flue gas from flowing downwards from the ash discharge port of a waste heat boiler scraper conveyor is described. The connection between the ash discharge pipe 5 of the waste heat boiler convection zone scraper conveyor and the inlet pipe 11 for flue gas entering the crusher in the convection zone is severed. A detachable flanged short section 6 with a length of 350mm is installed in the middle of the pipe. The detachable flanged short section 6 and the ash discharge pipe 5 of the convection zone scraper conveyor are fastened together by flange bolts. If flue gas blocks the ash discharge pipe 5 of the convection zone scraper conveyor, the bolts on the upper end of the detachable flanged short section 6 and the flange of the ash discharge pipe 5 of the waste heat boiler convection zone scraper conveyor are removed to complete the unblocking operation.

[0017] A 10mm gap 19 is left between the detachable flanged short section 6 and the inlet pipe 11 for flue gas entering the crusher in the convection zone. Four sets of nuts with a length of 35mm are installed at the lower flange opening of the gap, and the preload length of the bolts is 25mm. When ash feeding stops, a δ=0.8mm fluorocarbon color steel plate is installed on the side of the gap 19 near the detachable flanged short section 6, and 8×8mm packing is wrapped around the bottom of the fluorocarbon color steel plate.

[0018] Before ash delivery, remove the fluorocarbon steel plate and packing in gap 19, wrap 10×10mm packing around the flange of the detachable flanged short section, open the detachable manhole 7 on the inclined chute 8 leading out from the ash discharge pipe 5 of the convection zone scraper, close the gate valve 9 installed on the downward pipe of the inclined chute, start the convection zone scraper in a jog, and at the same time observe the water and damp soot in the scraper falling into the inclined chute 8 through the detachable manhole 7 until the soot is completely dry. When the soot is completely dry, install the detachable manhole 7, start the convection zone scraper 3 to continuously deliver ash until the ash delivery operation is completed. After the ash delivery is completed, open the gate valve 9 installed on the inclined chute 8, and guide the water and damp soot accumulated in the inclined chute 8 into the mobile ash transport vehicle below through the ground ash pipe 10 leading out from the inclined chute. After the ash delivery is completed, close the gate valve 9.

[0019] This utility model has been applied to the waste heat boiler ash conveying system of the side-blown melting and casting furnace in the nickel smelting workshop of our company. It has been used for 13 months and the effect is good. It has explored a new path for pneumatic ash conveying of waste heat boiler under positive pressure operation.

Claims

1. A structure for preventing flue gas from flowing downwards from the ash outlet of a waste heat boiler scraper conveyor, characterized in that, It includes the waste heat boiler radiant zone (1), the waste heat boiler convection zone (2), the radiant zone scraper conveyor (4), the convection zone scraper conveyor (3), the convection zone ash discharge pipe (5), the convection zone flue ash inlet pipe (11) and the radiant zone ash discharge pipe (12). The connection between the ash discharge pipe (5) of the convection zone scraper conveyor and the inlet pipe (11) of the convection zone flue dust entering the crusher is cut off. A detachable flanged short section (6) is installed at the cut-off position. The upper part of the detachable flanged short section (6) and the ash discharge pipe (5) of the convection zone scraper conveyor are connected by flange bolts. A 10mm gap (19) is left between the lower part of the detachable flanged short section (6) and the inlet pipe (11) of the convection zone flue dust entering the crusher. A flange of the same size as the detachable flanged short section (6) is installed near the short section of the inlet pipe (11) of the convection zone flue dust entering the crusher. A fluorocarbon color steel plate with δ=0.8mm is installed in the gap (19).

2. The structure for preventing flue gas from flowing downwards from the ash outlet of the waste heat boiler scraper conveyor according to claim 1, characterized in that, The lower flange face of the detachable flanged short section (6) and the convection zone flue dust entering the crusher inlet pipe (11) is equipped with bolts with a length of 35mm and a bolt tightening distance of 25mm.

3. The structure for preventing flue gas from flowing downwards from the ash outlet of the waste heat boiler scraper conveyor according to claim 1, characterized in that, It also includes packing, with 8×8mm packing wrapped around the bottom of the fluorocarbon color steel plate.

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