A combined hot air circulation system of shaft furnace and shaft cooler

Abstract

The vertical furnace-vertical cooling machine combined hot air circulation system comprises a vertical furnace, a vertical cooling machine, a waste heat boiler, a circulating air pipe and a circulating air fan, the vertical furnace is connected with the vertical cooling machine and the circulating air fan through the circulating air pipe, the vertical cooling machine is connected with the waste heat boiler through the circulating air pipe, the circulating air fan is connected with the waste heat boiler through the circulating air pipe, and the waste heat boiler is connected with a generator set through a steam pipeline; the vertical furnace discharges the sintered ore pellets from the calcination of the ore powder, the vertical cooling machine stores and cools the discharged ore pellets, hot waste gas generated in the cooling process of the vertical cooling machine is transported to the waste heat boiler through the circulating air pipe, part of the hot waste gas in the waste heat boiler is transported to the vertical furnace and the vertical cooling machine through the circulating air fan, and the other part of the hot waste gas is transported to the generator set through the steam pipeline; the waste heat can be recovered to reduce the fuel consumption of coal gas and natural gas; and the waste heat is maximally recovered to generate electricity, so that double benefits of self-use and external supply are realized.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery technology, and in particular to a combined hot air circulation system of a vertical furnace and a vertical cooler. Background Technology

[0002] The vertical shaft furnace is responsible for evenly discharging the high-temperature roasted pellets. The surface temperature of the pellets discharged from the furnace is generally 400-700℃, and the internal temperature reaches around 750℃. If the sensible heat of this portion of the pellets can be recovered and utilized, it will be of great significance for energy conservation in the pelletizing process. However, due to technical limitations, the efficiency of waste heat recovery is generally not ideal, which seriously restricts the utilization of waste heat.

[0003] Therefore, it is necessary to provide a combined hot air circulation system of vertical furnace and vertical cooler to overcome the above-mentioned defects. Summary of the Invention

[0004] The purpose of this invention is to provide a combined hot air circulation system of vertical furnace and vertical cooler, which can recover and reuse waste heat, thereby reducing the consumption of fuels such as coal gas and natural gas; the recycling of hot waste gas keeps the internal temperature of the vertical furnace / vertical cooler stable, reduces local over-burning and under-burning of pellets in the furnace, and improves pellet strength and yield.

[0005] To achieve the above objectives, the present invention provides a vertical furnace-vertical cooler combined hot air circulation system, comprising: a vertical furnace, a vertical cooler, a waste heat boiler, circulating air ducts, and a circulating fan.

[0006] The vertical furnace is connected to the vertical cooler and the circulating fan through a circulating air duct. The vertical cooler is connected to the waste heat boiler through a circulating air duct. The circulating fan is connected to the waste heat boiler through a circulating air duct. The waste heat boiler is connected to the generator set through a steam pipe.

[0007] The vertical furnace roasts the ore powder into pellets and discharges them. The vertical cooler collects and cools the discharged pellets. The hot waste gas generated by the vertical cooler during the cooling process is transported to the waste heat boiler through a circulating air duct. A portion of the hot waste gas in the waste heat boiler is transported to the vertical furnace and the vertical cooler through a circulating fan. Another portion of the hot waste gas in the waste heat boiler is transported to the generator set through a steam pipeline.

[0008] Preferably, an ash storage bin is provided at the bottom of the vertical furnace, and an ash discharge valve is provided on the ash storage bin.

[0009] Preferably, a first temperature sensor is installed inside both the vertical furnace and the vertical cooler, and a second temperature sensor is installed inside both the waste heat boiler and the circulating air duct.

[0010] Preferably, the top of the vertical cooler is provided with a receiving hopper, and the bottom of the vertical cooler is provided with a discharge port.

[0011] Preferably, it also includes a hoisting feeding mechanism, which includes a support frame, a hoist, a wire rope, a guide rail, and a trolley. The support frame is inclinedly distributed between the ash storage bin of the vertical furnace and the top of the vertical furnace. The hoist is distributed adjacent to the support frame. The guide rail is installed on the support frame. The wire rope is wound on the hoist and connected to the trolley. The trolley travels along the guide rail.

[0012] Preferably, the system also includes a blower and an induced draft fan. The blower is connected to the vertical furnace via a circulating air duct, and the induced draft fan is connected between the vertical cooler and the blower via a circulating air duct. The circulating fan is connected to the blower via a circulating air duct.

[0013] Preferably, the circulating duct between the blower and the induced draft fan is equipped with a flow meter and a regulating valve, and the circulating duct between the blower and the circulating fan is also equipped with a flow meter and a regulating valve.

[0014] Compared with existing technologies, the advantages are: 1) Waste heat can be recovered and reused, thereby reducing the consumption of fuels such as coal gas and natural gas. On the other hand, the recycling of hot waste gas keeps the internal temperature of the vertical furnace 1 / vertical cooler stable, reducing local over-burning and under-burning of pellets in the furnace, and improving pellet strength and yield. Furthermore, another source of waste gas directly enters the waste heat boiler to produce steam for the generator set, which does not affect the hot air demand of the process in the furnace, and can maximize the recovery of waste heat for power generation, achieving dual benefits of self-use and external supply.

[0015] 2) It allows for convenient manual and periodic loading and unloading of stored mineral powder and ash for cleaning, eliminating the need to shut down the furnace for ash removal, reducing downtime for ash removal, ensuring continuous and stable operation of the vertical furnace, and improving the operating rate.

[0016] 3) A blower and an induced draft fan are connected in series between the vertical furnace, vertical cooler, and circulating fan. The blower pressurizes the air and the induced draft fan draws air under negative pressure, which works in conjunction with the circulating fan to form a front-to-back airflow drive structure. This effectively overcomes the flow resistance of the furnace body and pellet material, ensures that the hot exhaust gas circulates stably along the designed path, avoids airflow stagnation and short circuits, and makes the airflow in the circulating duct smoother, reducing the load on the circulating fan.

[0017] Other features and advantages of the invention will be set forth in the following description, and in part will be apparent from the description, or may be learned by practice of the invention. The features and advantages of the invention may be realized and obtained by means of the elements and combinations specifically pointed out in the appended claims. These and other features of the invention will become more apparent from the following description and the appended claims, or may be learned by practice of the embodiments described herein. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the combined hot air circulation system of vertical furnace and vertical cooler provided by the present invention.

[0020] Figure 2 for Figure 1 The diagram shows the structure of the winch feeding mechanism.

[0021] Attached reference numerals: 1. Vertical furnace; 11. Ash storage bin; 12. Ash discharge valve; 2. Vertical cooler; 21. Receiving hopper; 22. Ore discharge port; 3. Waste heat boiler; 4. Circulating fan; 5. Hoisting feeding mechanism; 51. Support frame; 52. Wire rope; 53. Guide rail; 54. Trolley; 6. Blower; 7. Exhaust fan. Detailed Implementation

[0022] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are merely for explaining the invention and are not intended to limit the invention.

[0023] It should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0024] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. Additionally, "multiple" and "several" mean two or more, unless otherwise explicitly specified.

[0026] Please see Figures 1 to 2 This invention provides a vertical furnace-vertical cooler combined hot air circulation system, comprising: a vertical furnace 1, a vertical cooler 2, a waste heat boiler 3, circulating air ducts, and a circulating fan 4.

[0027] The vertical furnace 1 is connected to the vertical cooler 2 and the circulating fan 4 through a circulating air duct. The vertical cooler 2 is connected to the waste heat boiler 3 through a circulating air duct. The circulating fan 4 is connected to the waste heat boiler 3 through a circulating air duct. The waste heat boiler 3 is connected to the generator set through a steam pipe.

[0028] The vertical furnace 1 is used to roast ore powder into pellets and discharge them. The vertical cooler 2 is used to collect and cool the discharged pellets. The hot waste gas generated by the vertical cooler 2 during the cooling process is transported to the waste heat boiler 3 through a circulating air duct. A portion of the hot waste gas in the waste heat boiler 3 is transported to the vertical furnace 1 and the vertical cooler 2 through a circulating fan 4. Another portion of the hot waste gas in the waste heat boiler 3 is transported to the generator set through a steam pipeline so that the generator set can use the hot waste gas to generate electricity.

[0029] Thus, the advantages of the technical solution of this invention are as follows: On the one hand, the hot waste gas returning from the waste heat boiler 3 is still at a relatively high temperature, and its return to the vertical furnace 1 and vertical cooler 2 can recover waste heat and reuse it, thereby reducing the consumption of fuels such as coal gas and natural gas. On the other hand, the recycling of hot waste gas keeps the internal temperature of the vertical furnace 1 / vertical cooler 2 stable, reducing local over-burning and under-burning of pellets in the furnace, and improving pellet strength and yield. Furthermore, another stream of hot waste gas directly enters the waste heat boiler 3 to generate steam for the generator set, which does not affect the hot air demand of the process in the furnace, and can maximize the recovery of waste heat for power generation, achieving dual benefits of self-use and external supply.

[0030] It should be noted that, in this embodiment, the circulating fan 4 can be model Y4-73-11No18D. In actual installation, the lower half of the vertical furnace 1 can be installed at a depth of -4 meters underground. The pellets discharged from the vertical furnace 1 are discharged into a pre-reserved underground pit, which can reduce the loss of sensible heat during the conveying process and reduce the climbing height and conveying distance of the trolley 54 of the hoisting feeding mechanism 5.

[0031] In one specific embodiment, an ash storage bin 11 is provided at the bottom of the vertical shaft furnace 1, and an ash discharge valve 12 is provided on the ash storage bin 11. The ash storage bin 11 is used to store the discharged pellet ash. When the ash discharge valve 12 is opened, the stored ash can be easily collected manually and periodically for cleaning without stopping the furnace for ash cleaning, reducing the downtime for ash cleaning, ensuring the continuous and stable operation of the vertical shaft furnace 1, and improving the operating rate.

[0032] In one specific embodiment, a first temperature sensor is installed inside both the vertical furnace 1 and the vertical cooler 2, and a second temperature sensor is installed inside the waste heat boiler 3 and the circulating air duct. The first temperature sensor is used to detect the temperature of the pellets, and the second temperature sensor is used to detect the temperature of the airflow. It should be noted that in this embodiment, the first sensor is a thermocouple with a detection temperature range of 0~800℃, and the second sensor is a resistance temperature detector (RTD).

[0033] In one specific embodiment, the vertical cooler 2 is provided with a receiving hopper 21 at the top and a discharge port 22 at the bottom. When the pellets fall from above, the receiving hopper 21 guides and gathers the material, ensuring that the material enters the equipment evenly, preventing uneven material distribution, jamming, or spillage. It also buffers the impact of the falling material, preventing direct erosion or damage to the furnace body or internal components, thus extending the equipment's lifespan. After the pellets have cooled, they can be stably discharged through the discharge port 22 without accumulation or blockage, ensuring the continuous operation of the vertical cooler 2.

[0034] In one specific embodiment, the vertical furnace-vertical cooler combined hot air circulation system further includes a hoisting and feeding mechanism 5. The feeding mechanism includes a support frame 51, a hoist, a wire rope 52, a guide rail 53, and a trolley 54. The support frame 51 is inclined at 45° between the ash storage bin 11 of the vertical furnace 1 and the top of the vertical furnace 1. The hoist is distributed adjacent to the support frame 51. The guide rail 53 is installed on the support frame 51. The wire rope 52 is wound on the hoist and connected to the trolley 54. The trolley 54 travels along the guide rail.

[0035] After the trolley 54 is loaded with pellets of ore in the pit, it is pulled by a winch along a steel cable 52. The steel cable 52 then pulls the trolley 54 upwards. When it reaches the top of the support frame 51, the pellets inside the trolley 54 are dumped out. Under its own weight, the trolley 54 moves downwards to a predetermined position at the bottom of the support frame 51, whereupon the trolley 54 is loaded with pellets of ore again, and the next loading process begins, repeating the cycle.

[0036] The technical parameters of the hoisting feeding mechanism 5 are as follows:

[0037] 1. Feeder type: Inclined bridge type

[0038] 2. Sloping bridge travel distance: Approximately 30m

[0039] 3. Inclination angle of the skew bridge: Approximately 45°

[0040] 4. Slant bridge track specifications: 38kg / m heavy rail / or 20# channel steel

[0041] 5. Maximum speed on the skew bridge: 45m / min

[0042] 6. Motor power: 37kW

[0043] 7. Wire rope diameter: 20mm

[0044] 8. Effective volume of the trolley (54): 1.5m³

[0045] In one specific embodiment, the vertical furnace-vertical cooler combined hot air circulation system further includes a blower 6 and an induced draft fan 7. The blower 6 is connected to the vertical furnace 1 through a circulation duct, the induced draft fan 7 is connected between the vertical cooler 2 and the blower 6 through a circulation duct, and the circulation fan 4 is connected to the blower 6 through a circulation duct.

[0046] Thus, a blower 6 and an induced draft fan 7 are connected in series between the vertical furnace 1, the vertical cooler 2, and the circulating fan 4. The blower 6 pressurizes and delivers air, while the induced draft fan 7 draws air under negative pressure in conjunction with the circulating fan 4, forming a front-to-back airflow drive structure. This effectively overcomes the flow resistance of the furnace body and the pellet material, ensures that the hot exhaust gas circulates stably along the designed path, avoids airflow stagnation and short circuits, and makes the airflow in the circulating duct smoother, reducing the load on the circulating fan 4.

[0047] In one specific embodiment, the circulating duct between the blower 6 and the induced draft fan 7 is equipped with a flow meter and a regulating valve, and the circulating duct between the blower 6 and the circulating fan 4 is also equipped with a flow meter and a regulating valve (e.g., a PID regulating valve). This allows for precise measurement of the hot exhaust gas flow rate entering the vertical furnace 1 and the vertical cooler 2, enabling fine adjustment of the circulating hot air volume according to roasting and cooling requirements, ensuring a uniform temperature field, and improving pellet quality.

[0048] Furthermore, the series connection of the two fans (blower 6 and induced draft fan 7) can achieve coordinated matching of air volume, air pressure, and hot air temperature by independently adjusting the speed of blower 6 and induced draft fan 7, adapting to fluctuations in production load, ensuring a stable balance between waste heat recovery and process heat, and thus precisely controlling the air pressure and air volume of the roasting section of vertical furnace 1 and the cooling section of vertical cooler 2, forming a uniform and stable temperature field and flow velocity field, improving the roasting quality and cooling uniformity of pellets, and reducing defects such as cracks and pulverization.

[0049] In this technical solution, the vertical furnace-vertical cooler combined hot air circulation system is also equipped with a PLC controller. The PLC controller is electrically connected to the frequency converters of the circulating fan 4, blower 6, and induced draft fan 7. The motor of the winch, the first temperature sensor, the second temperature sensor, the flow meter, and the regulating valve are electrically connected to the PLC controller. The PLC performs PID closed-loop control based on the circulating air volume signal detected by the flow meter, automatically adjusting the valve opening to achieve precise and constant regulation of the circulating hot exhaust gas volume, stabilizing the airflow and temperature field inside the vertical furnace 1 and the vertical cooler 2, and improving the system's thermal efficiency and operational stability. Furthermore, based on the temperature signals detected by the first and second temperature sensors, signals can be output to the frequency converters of the circulating fan 4, blower 6, and induced draft fan 7 to adjust the power of each fan, achieving online automated control.

[0050] The present invention is not limited to the description in the specification and embodiments, and thus other advantages and modifications can be readily realized by those skilled in the art. Therefore, the present invention is not limited to the specific details, representative devices and illustrated examples shown and described herein without departing from the spirit and scope of the general concept as defined by the claims and their equivalents.

Claims

1. A combined hot air circulation system of a vertical furnace and a vertical cooler, characterized in that, include: Vertical furnace (1), vertical cooler (2), waste heat boiler (3), circulating air duct and circulating fan (4). The vertical furnace (1) is connected to the vertical cooler (2) and the circulating fan (4) through a circulating air duct. The vertical cooler (2) is connected to the waste heat boiler (3) through a circulating air duct. The circulating fan (4) is connected to the waste heat boiler (3) through a circulating air duct. The waste heat boiler (3) is connected to the generator set through a steam pipe. The vertical furnace (1) roasts the ore powder into pellets and discharges them. The vertical cooler (2) collects and cools the discharged pellets. The hot waste gas generated by the vertical cooler (2) during the cooling process is transported to the waste heat boiler (3) through the circulating air duct. A portion of the hot waste gas in the waste heat boiler (3) is transported to the vertical furnace (1) and the vertical cooler (2) through the circulating fan (4). Another portion of the hot waste gas in the waste heat boiler (3) is transported to the generator set through the steam pipeline.

2. The vertical furnace-vertical cooler combined hot air circulation system as described in claim 1, characterized in that, The bottom of the vertical furnace (1) is provided with an ash storage bin (11), and an ash discharge valve (12) is provided on the ash storage bin (11).

3. The vertical furnace-vertical cooler combined hot air circulation system as described in claim 1, characterized in that, The vertical furnace (1) and the vertical cooler (2) are each equipped with a first temperature sensor, and the waste heat boiler (3) and the circulating air duct are equipped with a second temperature sensor.

4. The vertical furnace-vertical cooler combined hot air circulation system as described in claim 1, characterized in that, The top of the vertical cooler (2) is provided with a receiving hopper (21), and the bottom of the vertical cooler (2) is provided with a discharge port (22).

5. The vertical furnace-vertical cooler combined hot air circulation system as described in claim 1, characterized in that, It also includes a hoisting feeding mechanism (5), which includes a support frame (51), a hoist, a wire rope (52), a guide rail (53), and a trolley (54). The support frame (51) is inclinedly distributed between the ash storage bin (11) of the vertical furnace (1) and the top of the vertical furnace (1). The hoist is distributed adjacent to the support frame (51). The guide rail (53) is installed on the support frame (51). The wire rope (52) is wound on the hoist and connected to the trolley (54). The trolley (54) travels along the guide rail.

6. The vertical furnace-vertical cooler combined hot air circulation system as described in claim 1, characterized in that, It also includes a blower (6) and an induced draft fan (7). The blower (6) is connected to the vertical furnace (1) through a circulating air duct. The induced draft fan (7) is connected between the vertical cooler (2) and the blower (6) through a circulating air duct. The circulating fan (4) is connected to the blower (6) through a circulating air duct.

7. The vertical furnace-vertical cooler combined hot air circulation system as described in claim 6, characterized in that, The circulating duct between the blower (6) and the induced draft fan (7) is equipped with a flow meter and a regulating valve, and the circulating duct between the blower (6) and the circulating fan (4) is also equipped with a flow meter and a regulating valve.

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