Novel flue gas recycling system for four cooling sections of circular cooler

Abstract

A novel flue gas recycling system for four cooling sections of a circular cooler comprises the first cooling section, a first cooling fan, a second cooling section, a second cooling fan, a third cooling section, a third cooling fan, the fourth cooling section and a cooling pipeline of the circular cooler. The first cooling section, the second cooling section, the third cooling section and the fourth cooling section are distributed in the circumferential direction and connected into a continuous cooling loop through an overall rotary frame. The first cooling section, the second cooling section and the third cooling section are respectively connected with a first cooling fan, a second cooling fan and a third cooling fan; the fourth cooling section is connected with a cooling pipeline; and the second cooling fan extracts flue gas of the fourth cooling section of the circular cooler through the cooling pipeline and blows the flue gas into the second cooling section of the circular cooler to cool pellets. According to the novel flue gas recycling system for the four cooling sections of the circular cooler, a fourth cooling fan is omitted in the hot air process of the circular cooler, waste gas of the four cooling sections is extracted through a second cooling fan to cool pellets, the flue gas recycling efficiency is improved, and the cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical engineering, relates to supporting equipment for a pelletizing process, and specifically relates to a novel four-cooling section flue gas recovery and utilization system for an annular cooler. Background Art

[0002] At present, the pellet production process of "chain grate machine-rotary kiln-ring cooler" is one of the main production processes of iron ore pellets. In actual production, the ring cooler is divided into one cooling section, two cooling sections, three cooling sections, and four cooling sections along the material flow direction. The traditional hot air process is as follows: along the material flow direction, there are one cooling section, two cooling sections, three cooling sections, and four cooling sections. Each section is equipped with a cooling fan, and normal temperature air is blown into the bellows of the ring cooler. The air flow passes through the material layer from bottom to top to cool the pellets. The hot exhaust gas from the upper cover of the first cooling section enters the rotary kiln as "secondary air", the exhaust gas from the second cooling section goes to the upper cover of the chain grate preheating section as a heat source, the exhaust gas from the third cooling section is blown into the bellows of the chain grate machine through the blower dryer as a drying heat source, and the hot exhaust gas from the upper cover of the fourth cooling section is directly discharged.

[0003] In the traditional flue gas recovery system of the ring cooler, each section of the ring cooler corresponds to a fan. The pellets in the fourth cooling section are cooled by the fan (No. 4 cooling fan). The fan blows air from the bottom to the top through the material layer for cooling. The fan of the second cooling section (No. 2 cooling fan) extracts the exhaust gas from the upper cover of the fourth cooling section through the pipeline. In the traditional four-cooling section flue gas recovery system of the ring cooler, two fans are required. The cooling pipeline between the second cooling section and the fourth cooling section is led out from the upper cover of the fourth cooling section and connected to the inlet of the No. 2 fan. It is a pipeline laid in the air, which has safety risks: high-altitude working equipment is required during the construction process. If the operation is not careful or the equipment fails, it may cause people to fall or other accidents; maintenance difficulties: because the pipeline is located at a high altitude, maintenance and maintenance may face great difficulties. Whether it is cleaning, repairing or replacing parts of the pipeline, it is necessary to use high-altitude working equipment, which increases the difficulty and cost of maintenance; risk emission: if the pipeline laid at high altitude leaks or is damaged, it may cause flue gas to leak into the air, which has a negative impact on the human body and the environment.

[0004] In the prior art, a variety of patents related to the present invention have been proposed and applied in the field of metallurgical engineering technology. For example, patent CN113639565B discloses a pellet ring cooler air system, which optimizes the wind flow of the ring cooler, recycles the waste gas in the pellet cooling process, achieves zero emission of cooling waste gas, reduces heat loss, improves the cooling efficiency of the ring cooler, and reduces the power consumption of the fan. However, the patent does not adjust the number of fans in the fourth cooling section and the second cooling section, thereby reducing energy consumption and operating costs. Summary of the invention

[0005] In order to optimize the hot air flow of the ring cooler, the present invention provides a new type of ring cooler four-cooling section flue gas recovery and utilization system. The ring cooler adjusts the hot air flow and no longer uses the fourth cooling fan. Instead, the second cooling fan is used to suck the waste gas generated by the fourth cooling section to cool the pellets, thereby improving the flue gas reuse efficiency and saving costs.

[0006] The above object of the present invention is achieved through the following technical solutions:

[0007] A novel flue gas recovery and utilization system for four cooling sections of a ring cooler comprises a first cooling section and a first cooling fan, a second cooling section and a second cooling fan, a third cooling section and a third cooling fan, and a fourth cooling section and a cooling pipeline; the first cooling section, the second cooling section, the third cooling section and the fourth cooling section are distributed along the circumferential direction and are connected into a continuous cooling circuit through an integral rotating frame; the first cooling section, the second cooling section and the third cooling section are respectively connected to the first cooling fan, the second cooling fan and the third cooling fan; the fourth cooling section is connected to the cooling pipeline; the second cooling fan extracts the flue gas from the fourth cooling section of the ring cooler through the cooling pipeline, and blows it into the second cooling section of the ring cooler to cool the pellets.

[0008] Furthermore, the cooling pipeline is laid underground, led out from the wind box of the fourth cooling section of the ring cooler, runs underground, and comes out at the second cooling fan to connect with its inlet.

[0009] Furthermore, a shutter valve is provided on the upper cover of the fourth cooling section of the ring cooler.

[0010] Furthermore, the partitions of the wind boxes adjacent to each cold section of the annular cooler are arranged as shutter valves.

[0011] Furthermore, the shutter valve is made of stainless steel.

[0012] Furthermore, a tee is provided at the air inlet of the No. 2 cooling fan, one interface is connected to the fan air inlet, and the other two interfaces are respectively connected to the cooling pipe and the air, and a valve is provided at each of the two interfaces.

[0013] Furthermore, the negative pressure at the inlet of the No. 2 cooling fan is increased to extract the exhaust gas from the fourth cooling section.

[0014] The beneficial effects of the present invention compared with the prior art solutions are:

[0015] 1. Energy saving and consumption reduction: Cooling fans usually consume a lot of energy to operate. Through the innovation of the hot air process, it is possible to reasonably allocate fan resources without sacrificing cooling efficiency. Instead of configuring the No. 4 cooling fan, the function of the No. 2 cooling fan is enhanced to efficiently handle the exhaust gas cooling task of the four cooling sections, thereby achieving the effect of energy saving and consumption reduction, which can reduce energy costs and improve energy utilization efficiency.

[0016] 2. Reduce operating costs: The operation and maintenance costs of cooling fans are very high. Reasonable allocation of fan resources can reduce related operating and maintenance costs, thereby reducing the operating costs of the enterprise and improving profitability.

[0017] 3. Improved equipment safety: Cooling fans may generate wind shear noise, vibration and other problems during operation, which not only poses a potential risk to the health and safety of employees, but may also affect the normal operation of other equipment. Reasonable allocation of fan resources can reduce these risks and improve the safety of the working environment.

[0018] 4. Improved space utilization: Cooling fans usually take up a certain amount of space and are large in size. Reasonable allocation of fan resources can release more space for other uses and improve space utilization.

[0019] 5. Simplified management: Reasonable allocation of fan resources can simplify the management and maintenance of equipment. Adjusting the number of equipment can reduce the related management workload, improve work efficiency, and reduce human resource investment.

[0020] 6. Cooling pipes are highly safe: Underground pipes will not be affected by external weather conditions and will not be damaged by wind, rain and other weather factors, thereby improving the safety of the pipes. High-altitude pipes are easily affected by weather factors such as wind and rain, increasing the potential safety hazards of the pipes.

[0021] 7. Good pipe insulation effect: The underground environment is relatively stable and the temperature changes little. Laying pipes underground can take advantage of the temperature stability of the underground to provide better insulation effect and reduce energy loss; while pipes laid at high altitudes are easily affected by the external temperature and have poor insulation effect.

[0022] 8. Cooling pipes are easy to maintain: Pipes laid underground are relatively easy to inspect and maintain, and can be operated through underground passages and wellheads, while pipes laid at high altitudes require special equipment and personnel for maintenance, and the operation is more difficult.

[0023] 9. Shutter valves are easy to install: The installation process of shutter valves is simpler than that of refractory brick masonry. Refractory brick masonry requires complex construction processes such as bricklaying, seaming, and glue, while the installation of shutter valves only requires them to be correctly installed on the upper cover.

[0024] 10. Reduce construction labor costs: The installation of shutter valves is relatively simple and fast, and requires less manpower, so the construction labor costs can be reduced.

[0025] 11. Improve construction quality: Shutter valves are prefabricated in the factory with standardized dimensions and precise manufacturing processes, ensuring the stability of product quality. This standardized manufacturing process can avoid possible irregularities and errors in construction.

[0026] 12. Reduce construction time: Since the construction process of installing the shutter valve is relatively simple, the construction time can be reduced. In contrast, refractory brick masonry takes a longer time to complete because it is necessary to wait for the mortar to dry and harden.

[0027] 13. Enhanced fault response capability: The partitions of the bellows adjacent to the first and second cooling sections and the third and fourth cooling sections of the ring cooler are changed to shutter valves. If the No. 2 fan fails, the valve can be opened to allow the wind blown in by the No. 1 cooling fan and the No. 3 cooling fan to blow into the second and fourth cooling sections to cool the pellets. Wait until the No. 2 cooling fan fails and close the valve. Two valves are set at the two air inlets of the No. 2 cooling fan. If the cooling pipe or the fourth cooling section fails, the valve of the cooling pipe can be closed and the other valve can be opened. The No. 2 cooling fan can draw air to cool the pellets in the second cooling section. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] In the figure, 1, first cooling section; 2, second cooling section; 3, third cooling section; 4, fourth cooling section; 5, No. 1 cooling fan; 6, No. 2 cooling fan; 7, No. 3 cooling fan; 8, cooling pipe; 9, shutter valve. DETAILED DESCRIPTION

[0030] The present invention is described in detail below through specific embodiments, but the protection scope of the present invention is not limited thereto.

[0031] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships 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 direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0032] Unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] Example 1

[0034] The present embodiment provides a novel flue gas recovery and utilization system for four cooling sections of an annular cooler, comprising a first cooling section 1 and a first cooling fan 5, a second cooling section 2 and a second cooling fan 6, a third cooling section 3 and a third cooling fan 7, a fourth cooling section 4 and a cooling pipe 8 of the annular cooler; the first cooling section 1, the second cooling section 2, the third cooling section 3 and the fourth cooling section 4 are distributed along the circumferential direction, and are connected into a continuous cooling circuit through an overall rotating frame; the first cooling section 1, the second cooling section 2, and the third cooling section 3 are respectively connected to the first cooling fan 5, the second cooling fan 6, and the third cooling fan 7; the fourth cooling section 4 is connected to the cooling pipe 8; the second cooling fan 6 extracts the flue gas from the fourth cooling section 4 of the annular cooler through the cooling pipe 8, and blows it into the second cooling section 2 of the annular cooler to cool the pellets.

[0035] The working process of the novel flue gas recovery and utilization system of the four-cooling section of the ring cooler described in the present invention is as follows:

[0036] The pellets entering the ring cooler are evenly distributed on the ring cooler's trolley through the flat material ball in the feeding hopper. The trolley rotates continuously, so that the pellets flow evenly inside the ring cooler and enter the first cooling section 1, the second cooling section 2, the third cooling section 3, and the fourth cooling section 4 in turn.

[0037] The fan blows natural wind from bottom to top into the ring cooler through the bellows under the trolley. The cold air exchanges heat with the pellets inside the ring cooler and absorbs the heat released by the pellets. The trolley carries the pellets into the first cold section 1, and the cooling airflow cools the pellets. The airflow comes from the outside normal temperature air blown by the No. 1 cooling fan 5. After the air passes through the pellets, the temperature reaches about 1000℃. The hot exhaust gas returns to the rotary kiln through the pipeline and the kiln head cover in turn, and enters the second preheating section of the chain grate machine through the kiln tail cover to preheat the raw balls from top to bottom, enters the bellows of the second preheating section of the chain grate machine, and enters the exhaust drying section of the chain grate machine through the multi-tube dust collector and the heat recovery fan to dry the raw balls from top to bottom, and finally is discharged into the atmosphere through the main electrostatic precipitator, the main exhaust fan, and the desulfurization and denitrification system.

[0038] The trolley carries the pellets into the second cooling section 2, where the cooling airflow cools the pellets. The airflow temperature after the pellets are cooled reaches about 600°C. The airflow comes from the flue gas drawn from the fourth cooling section of the ring cooler by the second cooling fan 6 through the cooling pipe 8, and then enters the chain grate preheating section through the hot air pipe to preheat the green pellets from top to bottom, and finally discharged into the air through the main electrostatic precipitator, the main exhaust fan, and the desulfurization and denitrification system.

[0039] The trolley carries the pellets into the third cooling section 3, where the cooling airflow cools the pellets. The airflow temperature after the pellets are cooled reaches about 250°C. The airflow comes from the third cooling fan 7, which blows in the ambient air, and then passes through the hot air duct and the drying fan to the chain grate machine blowing and drying section to dry the green pellets from bottom to top, and finally is discharged into the air through the furnace hood dust collector and the furnace hood fan.

[0040] The trolley carries the pellets into the fourth cooling section 4, where the cooling airflow cools the pellets, and the airflow temperature after cooling the pellets reaches about 80° C. The airflow comes from the ambient air at room temperature blown in by the second cooling fan 6 through the shutter valve 9 on the cover of the fourth cooling section 4.

[0041] When the pellet temperature reaches the requirement, it is discharged through the discharge port.

[0042] Compared with the prior art, the present invention has made significant improvements and innovations in reducing energy consumption and improving the safety of the working environment. Through the innovation of the hot air process, the present invention realizes the reasonable allocation of fan resources without sacrificing cooling efficiency. The fourth cooling fan is no longer configured. Instead, the function of the second cooling fan is enhanced to efficiently handle the exhaust gas cooling task of the four cooling sections, which not only reduces the operation and maintenance costs of the cooling fan, but also improves the safety of employees' operations. In addition, the present invention also shows obvious advantages in space utilization. The reasonable allocation of fan resources means freeing up more space, which can be used for other purposes and improve space utilization.

[0043] The above-described embodiments are only preferred embodiments of the present invention, but not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A new type of flue gas recovery and utilization system for the fourth cooling stage of annular cooler, characterized in that: The invention comprises a first cooling section (1) and a first cooling fan (5), a second cooling section (2) and a second cooling fan (6), a third cooling section (3) and a third cooling fan (7), and a fourth cooling section (4) and a cooling pipeline (8) of a ring cooler; the first cooling section (1), the second cooling section (2), the third cooling section (3) and the fourth cooling section (4) are distributed along the circumferential direction and connected to form a continuous cooling circuit through an integral revolving frame; the first cooling section (1), the second cooling section (2) and the third cooling section (3) are respectively connected to the first cooling fan (5), the second cooling fan (6) and the third cooling fan (7); the fourth cooling section (4) is connected to the cooling pipeline (8); the second cooling fan (6) extracts the smoke from the fourth cooling section (4) of the ring cooler through the cooling pipeline (8) and blows the smoke into the second cooling section (2) of the ring cooler to cool the pellets.

2. According to the novel four-stage flue gas recovery and utilization system of the ring cooler according to claim 1, it is characterized in that: The cooling pipeline (8) is laid underground, is led out from the wind box of the fourth cooling section (4) of the ring cooler, runs underground, and is connected to the inlet of the second cooling fan (6).

3. According to the novel four-stage flue gas recovery and utilization system of the ring cooler according to claim 1, it is characterized in that: A shutter valve (9) is provided on the upper cover of the fourth cooling section (4) of the annular cooler.

4. According to the novel four-stage flue gas recovery and utilization system of the ring cooler according to claim 1, it is characterized in that: The partitions of the wind boxes adjacent to each cooling section of the annular cooler are all provided with shutter valves (9).

5. A novel flue gas recovery and utilization system for four cooling stages of annular cooler according to claim 3 or claim 4, characterized in that: The shutter valve (9) is made of stainless steel.

6. The novel four-stage flue gas recovery and utilization system of annular cooler according to claim 1 is characterized in that: A three-way connection is provided at the air inlet of the second cooling fan (6), one interface is connected to the fan air inlet, and the other two interfaces are respectively connected to the cooling pipe (8) and the air, and a valve is respectively provided at these two interfaces.

7. The novel flue gas recovery and utilization system of the fourth cooling section of the ring cooler according to claim 1 is characterized in that: The negative pressure at the inlet of the second cooling fan (6) increases, extracting the exhaust gas from the fourth cooling section (4).

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