A shaft furnace pellet waste heat recovery device

Abstract

A kind of shaft furnace pellet waste heat recovery device, including the air cooling box being arranged above the pellet belt cooler for conveying pellet, the air cooling box includes the top plate being arranged in parallel above the pellet belt cooler, the lower surface of top plate is fixedly connected with two mutually parallel end plates, multiple mutually parallel partition plates are fixedly connected between the two end plates, partition plate is vertically arranged relative to pellet belt cooler and is close to pellet belt cooler, distance is left between adjacent two partition plates to form air passage, the end plate close to the discharge end of pellet belt cooler is provided with air inlet fan for conveying gas into air passage, one end plate close to the incoming material end of pellet belt cooler is communicated with heat exchanger by air outlet pipe, heat exchanger is communicated with water inlet pipe and water outlet pipe.The utility model and the heat of pellet is transferred to the water in heat exchanger, realize the recycling of pellet waste heat, and direct cold gas can be avoided blowing on high-temperature pellet, avoid the change of character caused by the rapid drop of temperature of pellet.

Description

Technical Field

[0001] This utility model relates to the field of vertical shaft furnace pellet production technology, specifically a waste heat recovery device for vertical shaft furnace pellet production. Background Technology

[0002] A pelletizing shaft furnace is a type of vertical furnace used for roasting metallurgical pellets. The pellet production process includes batching, drying, milling, pelletizing, roasting, and cooling. During pellet production, after batching, drying, milling, and pelletizing, qualified green pellets are fed into the shaft furnace for roasting. After drying and preheating, they are roasted in an oxidizing atmosphere at a temperature typically between 1000℃ and 1200℃. The roasted pellets are then conveyed by a chain conveyor to a pellet cooler for cooling, and then either sent to a pelletizing yard for storage or directly to downstream processes.

[0003] Because pellets still have a high temperature on the pellet cooling machine, various pellet waste heat recovery technologies have been continuously developed in recent years. By recovering the waste heat of pellets for production and daily life in the factory area, enterprise costs can be reduced and efficiency improved.

[0004] Currently, most pellet waste heat recovery technologies achieve heat absorption by directly blowing air onto the pellets in the pellet cooler, forming a hot airflow that then transfers the heat to the water through a heat exchanger, thus completing waste heat recovery. However, directly blowing cold gas onto the pellets causes a rapid drop in pellet temperature, which may alter the pellet's properties and adversely affect subsequent production. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a waste heat recovery device for vertical shaft furnace pellets, which can cool down the pellets and transfer the heat of the pellets to the water in the heat exchanger, thereby realizing the recovery and utilization of the waste heat of the pellets. It can also prevent cold gas from being directly blown onto the high-temperature pellets, thus preventing the pellets from changing their properties due to a rapid drop in temperature.

[0006] To achieve the above objectives, the specific solution adopted by this utility model is as follows: a vertical shaft furnace pellet waste heat recovery device, including an air-cooled box installed above a pelletizing belt cooler for conveying pellets. The air-cooled box includes a top plate installed parallel to the pelletizing belt cooler. Two parallel end plates are fixedly connected to the lower surface of the top plate. Multiple parallel partitions are fixedly connected between the two end plates. The partitions are installed perpendicular to and close to the pelletizing belt cooler. A distance is left between two adjacent partitions to form an air passage. An air inlet fan for conveying gas into the air passage is installed on one end plate near the discharge end of the pelletizing belt cooler. A heat exchanger is connected to one end plate near the material inlet end of the pelletizing belt cooler through an air outlet pipe. The heat exchanger is connected to an inlet water pipe and an outlet water pipe.

[0007] As a further optimization of the above-mentioned vertical furnace pellet waste heat recovery device: an air inlet pipe is provided on one end plate near the discharge end of the pellet cooler, the air inlet fan is connected to the air inlet pipe, and the air inlet fan is set upward.

[0008] As a further optimization of the above-mentioned vertical shaft furnace pellet waste heat recovery device: the heat exchanger includes an outer shell, in which multiple heat exchange tubes are vertically arranged. The lower end of the heat exchange tubes is connected to the water inlet pipe, the upper end of the heat exchange tubes is connected to the water outlet pipe, the bottom of the outer shell is connected to the air outlet pipe, and the top of the outer shell is provided with a waste gas outlet.

[0009] As a further optimization of the above-mentioned vertical shaft furnace pellet waste heat recovery device: each of the water inlet pipe and the water outlet pipe is connected to a water distributor, the water distributor is located in the outer shell, and the two ends of the heat exchange tube are connected to the two water distributors respectively.

[0010] As a further optimization of the above-mentioned vertical shaft furnace pellet waste heat recovery device: at least one annular baffle is horizontally arranged in the outer shell, and the heat exchange tube passes through the inner hole of the baffle.

[0011] As a further optimization of the above-mentioned vertical furnace pellet waste heat recovery device: a filter mechanism is provided at the bottom of the outer shell, which is used to filter the gas flowing into the outer shell from the air outlet pipe.

[0012] As a further optimization of the above-mentioned vertical shaft furnace pellet waste heat recovery device: the filtration mechanism includes a cylindrical filter screen, which is fixedly connected to the inner wall of the outer shell through multiple connecting rods. The lower end of the filter screen is connected to the air outlet pipe, and a diverter plate is fixedly installed inside the upper end of the filter screen to divert gas onto the filter screen.

[0013] As a further optimization of the above-mentioned vertical shaft furnace pellet waste heat recovery device: the diversion plate is hemispherical, and the opening of the diversion plate is set upward.

[0014] As a further optimization of the above-mentioned vertical furnace pellet waste heat recovery device: the air outlet pipe passes through the outer shell and is connected to an air guide tube, which is located inside the filter screen, and a distance is left between the air guide tube and the lower end of the filter screen to form a collection area.

[0015] As a further optimization of the above-mentioned vertical furnace pellet waste heat recovery device: the lower part of the filter screen gradually tapers from top to bottom.

[0016] Beneficial effects: This invention can cool down the pellets and transfer the heat of the pellets to the water in the heat exchanger, realizing the recovery and utilization of the waste heat of the pellets; This invention can avoid cold gas being blown directly onto the high temperature pellets, and avoid the pellets changing their properties due to rapid temperature drop. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a structural diagram of an air-cooled box; Figure 3 This is a schematic diagram of the heat exchanger. Figure 4 This is a schematic diagram of the filtration mechanism.

[0018] Attached diagram descriptions: 1-Pelletizer with cooling system, 2-Pellet, 3-Air-cooled box, 4-Inlet pipe, 5-Inlet fan, 6-Outlet pipe, 7-Heat exchanger, 8-Water inlet pipe, 9-Water outlet pipe, 10-Exhaust gas outlet, 11-Top plate, 12-Baffle plate, 13-Water distributor, 14-Heat exchange tube, 15-Baffle, 16-Air guide tube, 17-Flow divider plate, 18-Connecting rod, 19-Filter screen, 20-Collection area. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] like Figures 1 to 3 As shown, a vertical shaft furnace pellet waste heat recovery device includes an air-cooled box 3 installed above a pellet cooler 1 for conveying pellets 2. The air-cooled box 3 includes a top plate 11 installed parallel to the pellet cooler 1. Two parallel end plates are fixedly connected to the lower surface of the top plate 11. Multiple parallel partitions 12 are fixedly connected between the two end plates. The partitions 12 are installed perpendicular to and close to the pellet cooler 1. A distance is left between two adjacent partitions 12 to form an air passage. An air inlet fan 5 for conveying gas into the air passage is installed on one end plate near the discharge end of the pellet cooler 1. A heat exchanger 7 is connected to one end plate near the receiving end of the pellet cooler 1 through an air outlet pipe 6. The heat exchanger 7 is connected to an inlet water pipe 8 and an outlet water pipe 9.

[0021] After pellet 2 is produced, it is transferred to the pellet cooler 1 for cooling. The pellet cooler 1 continuously transfers pellet 2, and during this transfer process, the waste heat recovery device of this invention is used to recover and utilize the waste heat of pellet 2. Specifically, during the process of conveying pellet 2 in the pellet cooler 1, gas is supplied into the air-cooled box 3 by the inlet fan 5. The gas enters the air-cooled box 3 from the side near the discharge end of the pellet cooler 1 and forms an airflow in the air passage. Because the baffle 12 is close to the pellet cooler 1, the airflow in the air passage can directly contact the pellet 2, thereby cooling the pellet 2 and heating the gas. The heated gas enters the heat exchanger 7 through the outlet pipe 6 and exchanges heat with the water in the heat exchanger 7, thereby heating the water. The heated water can be used for production and daily life in the factory area, thus realizing the recovery and utilization of the waste heat of pellet 2.

[0022] On the other hand, as pellet 2 moves on the pellet cooler 1, its temperature gradually decreases. Therefore, the temperature of pellet 2 near the incoming end is higher than that near the outgoing end. Meanwhile, the airflow in the gas duct flows from the outgoing end to the incoming end. Figure 1 As shown in the airflow direction, the temperature of the gas near the inlet end is higher than that of the gas near the outlet end. Therefore, the temperature difference between the gas and the pellet 2 is similar at the inlet end and the outlet end, thus achieving a gradual cooling of the pellet 2 and avoiding the cold gas directly acting on the high-temperature pellet 2, which would cause the pellet 2 to be cooled rapidly and affect its properties.

[0023] This invention can cool down the pellets 2 and transfer the heat of the pellets 2 to the water in the heat exchanger 7, thereby realizing the recovery and utilization of the waste heat of the pellets 2. This invention can prevent cold gas from being blown directly onto the high temperature pellets 2, and prevent the pellets 2 from changing their properties due to a rapid drop in temperature.

[0024] Furthermore, an air inlet pipe 4 is installed on one end plate near the discharge end of the hot pellet cooler 1. An air inlet fan 5 is connected to the air inlet pipe 4 and is positioned upwards. By positioning the air inlet fan 5 upwards, dust generated on the hot pellet cooler 1 can be prevented from being sucked in, ensuring gas cleanliness and simplifying the subsequent gas filtration process.

[0025] The specific structure of heat exchanger 7 is as follows: heat exchanger 7 includes a shell, in which multiple heat exchange tubes 14 are vertically arranged. The lower end of the heat exchange tubes 14 is connected to the inlet water pipe 8, the upper end of the heat exchange tubes 14 is connected to the outlet water pipe 9, the bottom of the shell is connected to the air outlet pipe 6, and the top of the shell is provided with an exhaust gas outlet 10. By placing the inlet water pipe 8 at the bottom and the outlet water pipe 9 at the top, it can be ensured that the heat exchange tubes 14 are filled with water, thereby ensuring heat exchange efficiency.

[0026] To ensure that water flows evenly into the heat exchange tube 14, each of the inlet pipe 8 and outlet pipe 9 is connected to a water distributor 13. The water distributor 13 is located inside the outer casing, and both ends of the heat exchange tube 14 are connected to the two water distributors 13 respectively. The water distributor 13 has a cavity, a main inlet / outlet for connecting the inlet pipe 8 or the outlet pipe 9, and multiple secondary inlets / outlets for connecting the heat exchange tube 14. This is conventional technology and will not be described in detail here.

[0027] To further improve heat exchange efficiency, at least one annular baffle 15 is horizontally arranged in the outer shell, and the heat exchange tube 14 passes through the inner hole of the baffle 15. By setting the baffle 15, the hot gas can be confined to the vicinity of the heat exchange tube 14, preventing the hot gas from flowing directly through the gap between the heat exchange tube 14 and the outer shell, thereby achieving the effect of improving heat exchange efficiency.

[0028] In order to ensure the cleanliness of the hot gas in contact with the heat exchange tube 14 and to prevent impurities in the hot gas from adhering to the heat exchange tube 14 and causing a reduction in the heat exchange efficiency of the heat exchange tube 14, a filter mechanism is provided at the bottom of the outer shell. The filter mechanism is used to filter the gas flowing into the outer shell from the air outlet duct 6.

[0029] The specific structure of the filtration mechanism is as follows: The filtration mechanism includes a cylindrical filter screen 19, which is fixedly connected to the inner wall of the outer shell through multiple connecting rods 18. The lower end of the filter screen 19 is connected to the air outlet pipe 6, and a flow divider plate 17 is fixedly installed inside the upper end of the filter screen 19. The flow divider plate 17 is used to divide the gas onto the filter screen 19. After the hot gas enters the heat exchanger 7 from the air outlet pipe 6, it first enters the inner side of the filter screen 19, and then is dispersed and guided onto the filter screen 19 under the action of the flow divider plate 17. After being filtered by the filter screen 19, the gas flows upward and contacts the heat exchange tube 14 to achieve heat exchange.

[0030] Furthermore, the manifold 17 is hemispherical in shape, and the opening of the manifold 17 is oriented upwards.

[0031] Considering that impurities filtered by filter 19 will adhere to filter 19 and eventually fall off, to prevent these falling impurities from entering the air outlet duct 6, the air outlet duct 6 passes through the outer casing and connects to an air guide duct 16. The air guide duct 16 is located inside filter 19, and a distance is left between the air guide duct 16 and the lower end of filter 19 to form a collection area 20. Based on this design, when impurities fall off filter 19, they can fall downwards into the collection area 20 and be temporarily stored, thus preventing them from falling directly into the air outlet duct 6. Furthermore, an inspection port can be provided in the part of the outer casing corresponding to the collection area 20 to periodically clean out the temporarily stored impurities.

[0032] Furthermore, the lower part of the filter 19 gradually tapers from top to bottom.

[0033] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A waste heat recovery device for vertical shaft furnace pelletizing, characterized in that, The equipment includes an air-cooled box (3) installed above the pellet cooler (1) for conveying pellets (2). The air-cooled box (3) includes a top plate (11) installed parallel to the top of the pellet cooler (1). Two parallel end plates are fixedly connected to the lower surface of the top plate (11). Multiple parallel partitions (12) are fixedly connected between the two end plates. The partitions (12) are set perpendicular to the pellet cooler (1) and close to the pellet cooler (1). A distance is left between two adjacent partitions (12) to form an air passage. An air inlet fan (5) for conveying gas into the air passage is installed on one end plate near the discharge end of the pellet cooler (1). A heat exchanger (7) is connected to one end plate near the material inlet end of the pellet cooler (1) through an air outlet pipe (6). The heat exchanger (7) is connected to an inlet water pipe (8) and an outlet water pipe (9).

2. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 1, characterized in that, An air inlet pipe (4) is installed on one end plate near the discharge end of the gluten cooler (1). The air inlet fan (5) is connected to the air inlet pipe (4) and is positioned upwards.

3. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 1, characterized in that, The heat exchanger (7) includes a shell, in which a plurality of heat exchange tubes (14) are vertically arranged. The lower end of the heat exchange tubes (14) is connected to the water inlet pipe (8), the upper end of the heat exchange tubes (14) is connected to the water outlet pipe (9), the bottom of the shell is connected to the air outlet pipe (6), and the top of the shell is provided with an exhaust gas outlet (10).

4. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 3, characterized in that, The inlet pipe (8) and the outlet pipe (9) are each connected to a water distributor (13). The water distributor (13) is located in the outer shell. The two ends of the heat exchange pipe (14) are connected to the two water distributors (13).

5. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 3, characterized in that, At least one annular baffle (15) is horizontally arranged in the outer casing, and the heat exchange tube (14) passes through the inner hole of the baffle (15).

6. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 3, characterized in that, A filter mechanism is provided at the bottom of the housing, which is used to filter the gas flowing into the housing from the air outlet pipe (6).

7. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 6, characterized in that, The filtration mechanism includes a cylindrical filter screen (19), which is fixedly connected to the inner wall of the outer shell by multiple connecting rods (18). The lower end of the filter screen (19) is connected to the air outlet pipe (6). A diverter plate (17) is fixedly installed inside the upper end of the filter screen (19), which is used to divert gas to the filter screen (19).

8. The waste heat recovery device for vertical shaft furnace pelletizing as described in claim 7, characterized in that, The diverter plate (17) is hemispherical in shape, and the opening of the diverter plate (17) is facing upward.

9. A waste heat recovery device for vertical shaft furnace pelletizing as described in claim 7, characterized in that, The air outlet pipe (6) passes through the outer shell and is connected to the air guide tube (16). The air guide tube (16) is located inside the filter screen (19), and a distance is left between the air guide tube (16) and the lower end of the filter screen (19) to form a collection area (20).

10. A waste heat recovery device for vertical shaft furnace pelletizing as described in claim 9, characterized in that, The lower part of the filter (19) gradually tapers from top to bottom.

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