Hot air backflow device for producing and processing superfine slag powder

Abstract

The utility model discloses a hot air backflow device for producing and processing superfine slag powder, which comprises a hot air furnace, a vertical mill and a hot air pipe, an exhaust pipe is arranged at the top of the vertical mill, and a primary dust remover, a secondary dust remover, an induced draft fan, a first temperature sensor and a three-way joint are sequentially mounted on the exhaust pipe along the airflow direction; one outlet of the three-way connector is connected with a first backflow pipe communicated with the hot air pipe, a first control valve is installed on the first backflow pipe, a second control valve is installed on the hot air pipe between the first backflow pipe and the hot air furnace, the other outlet of the three-way connector is connected with a second backflow pipe, and a waste heat recoverer is arranged at an outlet of the second backflow pipe. An air inlet pipe, an air outlet pipe and a smoke exhaust pipe are arranged on the waste heat recoverer, and the air outlet pipe is communicated with a combustor of the hot blast stove. The device not only can effectively improve the utilization rate of hot air heat energy, but also can greatly reduce the operation cost of the device, and has the advantages of advanced structural design and remarkable energy-saving effect.

Description

Technical Field

[0001] The utility model belongs to the technical field of solid waste resource processing and treatment, and in particular relates to a hot air reflux device for slag micro-powder processing. Background Art

[0002] Slag powder is a by-product, mainly derived from metallurgy, chemical industry, electric power and other production fields. In these industries, ironmaking, steelmaking, electrolytic aluminum and other processes are often required. These processes will produce a large amount of high-temperature molten materials, including slag, smelting slag and furnace slag. These materials are crushed into powder after cooling to form slag powder. The main components of slag powder are oxides, silicates, etc., which contain a large amount of active silicates. It has good cement properties and high strength. It is mainly added to cement or concrete. As a new admixture for high-performance concrete, it can improve the durability of concrete, resistance to seawater erosion, reduce hydration heat and other properties, and can reduce the amount of cement clinker in concrete. And every ton of slag powder used to replace silicate cement can reduce 0.77 tons of carbon emissions, and the comprehensive emissions are less than 10% of cement. It can be inferred that slag powder has broad market prospects in the future. At present, the process flow of slag micro powder production line mainly includes feeding, conveying, drying, grinding, storage and other processes. Vertical mill is the key equipment used in the slag micro powder grinding production process. In the process of grinding slag micro powder in vertical mill, it is necessary to introduce hot air into the vertical mill using hot air furnace, which is not only used to keep the slag micro powder dry, but also to blow the ground mineral powder out of the vertical mill. The hot air introduced into the vertical mill is directly discharged from the vertical mill together with the mineral powder, resulting in a large amount of heat loss directly, causing waste of resources and seriously increasing transportation costs. In the existing technology, although there is a precedent of returning the hot air discharged from the vertical mill to the hot blast furnace for heat energy utilization, the hot air return device used in this technology is relatively rough in structure. The hot air is returned to the hot blast furnace for reheating and use. The hot blast furnace still needs to burn energy to heat the hot air, and there is a problem of low utilization rate of hot air heat energy. At the same time, the dust content in the hot air is large. When the hot air returns to the hot blast furnace for heating, it will increase the combustion load of the hot blast furnace, affect the combustion efficiency of the hot blast furnace, increase the energy consumption of the system, and the operation cost of the device is still high. Therefore, it is an objective need to develop a hot air return device for slag micro-powder processing with advanced structure, high heat energy utilization rate, and effective reduction in operation cost. Summary of the invention

[0003] The utility model aims to provide a hot air reflux device for slag micro-powder processing which has advanced structure, high thermal energy utilization rate and can effectively reduce operation cost.

[0004] The purpose of the utility model is achieved in this way, including a hot blast furnace, a vertical mill and a hot blast pipe installed between the hot blast furnace and the vertical mill, an exhaust duct is arranged on the top of the vertical mill, a primary dust collector, a secondary dust collector, an induced draft fan, a first temperature sensor and a three-way joint are sequentially installed on the exhaust duct along the air flow direction, one outlet of the three-way joint is connected with a first return pipe connected with the hot blast pipe, a first control valve is installed on the first return pipe, a second control valve is installed on the hot blast pipe between the first return pipe and the hot blast furnace, the other outlet of the three-way joint is connected with the second return pipe, a waste heat recovery device is arranged at the outlet of the second return pipe, an air inlet pipe, an air outlet pipe and a smoke exhaust pipe are respectively arranged on the waste heat recovery device, and the air outlet pipe is connected with the burner of the hot blast furnace.

[0005] Compared with the existing hot air reflux device, the advantages of this device are: based on the technical foundation of the original structure, this device increases the efficiency of hot air dust removal, and uses a two-stage dust removal method to greatly reduce the dust content of the hot air. At the same time, the hot air after dust removal does not directly enter the hot air furnace for re-combustion, but needs to be temperature measured and then select a reasonable reflux pipeline for reflux. If the monitored hot air temperature meets the temperature requirement for entering the vertical mill, the hot air after dust removal does not need to enter the waste heat recovery box for heat recovery, nor does it need the hot air furnace to work. It only needs to flow back to the vertical mill through the first reflux pipe for recycling. If the monitored hot air temperature does not meet the temperature requirement for entering the vertical mill, the hot air after dust removal does not need to enter the waste heat recovery box for heat recovery, nor does it need the hot air furnace to work. It only needs to flow back to the vertical mill through the first reflux pipe for recycling. When the temperature requirement of the vertical mill can be met, the hot air needs to enter the waste heat recovery device, and after heat exchange with the gas or air that needs to enter the hot blast furnace, the gas and air that have absorbed heat will enter the hot blast furnace for combustion. This structure can not only reduce the combustion load of the hot blast furnace, improve the combustion efficiency of the hot blast furnace, and ensure the stability of the temperature and flow of the hot air entering the vertical mill, but also the preheated gas enters the hot blast furnace for combustion, and the combustion speed is fast, which can effectively reduce the gas consumption, effectively improve the utilization rate of hot air thermal energy, and greatly reduce the operating cost of the device. It has the advantages of advanced structural design and significant energy-saving effect, and is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0007] Figure 2 It is a schematic diagram of the structure of the secondary dust collector 6 in the utility model;

[0008] Figure 3 It is a schematic diagram of the structure of the waste heat recovery device 12 in the utility model;

[0009] In the figure: 1-hot blast furnace, 2-vertical mill, 3-hot blast pipe, 4-exhaust duct, 5-primary dust collector, 6-secondary dust collector, 61-filter, 62-rotating shaft, 63-motor, 64-cleaning plate, 65-ash collecting hopper, 7-induced draft fan, 8-first temperature sensor, 9-tee joint, 10-first return pipe, 11-second return pipe, 12-waste heat recovery device, 121-first partition, 122-second partition, 123-air inlet chamber, 124-heat exchange chamber, 125-air outlet chamber, 126-heat exchange tube, 127-baffle, 13-inlet pipe, 14-outlet pipe, 15-exhaust pipe, 16-thermostat, 17-second temperature sensor, 18-air supply pipe, 19-electric heating rod. DETAILED DESCRIPTION

[0010] The present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited in any way. Any changes or improvements made based on the teachings of the present invention belong to the protection scope of the present invention.

[0011] like Figures 1 to 3 As shown, the utility model comprises a hot blast furnace 1, a vertical mill 2 and a hot blast pipe 3 installed between the hot blast furnace 1 and the vertical mill 2. The hot blast furnace 1 adopts a gas-fired hot blast furnace used in the prior art. The hot blast pipe 3 is used to transport the hot blast generated by the hot blast furnace to the vertical mill 2. The vertical mill 3 adopts a vertical mill used in the prior art. An exhaust pipe 4 is arranged on the top of the vertical mill 2. A primary dust collector 5, a secondary dust collector 6, an induced draft fan 7, a first temperature sensor 8 and a three-way joint 9 are sequentially installed on the exhaust pipe 4 along the air flow direction. The first temperature sensor 8 is a three-way joint used in the prior art. The structure is directly purchased according to the requirements of use. One outlet of the three-way joint 9 is connected to a first return pipe 10 connected to the hot air pipe 3. A first control valve is installed on the first return pipe 10. A second control valve is installed on the hot air pipe 3 between the first return pipe 10 and the hot air stove 1. The other outlet of the three-way joint 9 is connected to a second return pipe 11. The outlet of the second return pipe 11 is provided with a waste heat recovery device 12. The waste heat recovery device 12 is respectively provided with an air inlet pipe 13, an air outlet pipe 14 and a smoke exhaust pipe 15. The air outlet pipe 14 is connected to the burner of the hot air stove 1.

[0012] The operation process of the device is as follows: the hot air generated by the combustion of the hot blast furnace 1 enters the vertical mill 2 through the hot blast pipe 3. After the slag powder is ground in the vertical mill 2, it is discharged through the exhaust pipe 4 with the hot air under the action of the induced draft fan 7 and first enters the primary dust collector 5. After the primary dust removal treatment, most of the slag powder in the hot air is separated and recovered, and a small part of the slag powder enters the secondary dust collector 6 with the hot air. After the dust removal treatment of the secondary dust collector 6, the small amount of slag powder carried in the hot air is completely separated and recovered. At this time, the second temperature sensor 8 can timely monitor the temperature of the hot air discharged from the secondary dust collector 6. If the hot air temperature monitored by the second temperature sensor 8 reaches the standard temperature specified by the vertical mill 2, the first control valve is opened and the second control valve is closed. The hot blast furnace 1 stops burning, and the hot air discharged from the secondary dust collector 6 is refluxed to the vertical mill 2 through the first reflux pipe 10 for recycling. If the hot air temperature monitored by the second temperature sensor 8 cannot meet the standard temperature specified by the vertical mill 2, the hot air will be discharged from the secondary dust collector 6 through the first reflux pipe 10. The hot air discharged from the secondary dust collector 6 flows back to the waste heat recovery device 12 through the second return pipe 11, and after heat exchange with the gas or air that needs to enter the hot blast stove 1, the gas and air after absorbing heat enter the hot blast stove 1 for combustion, and the hot air with reduced temperature is discharged from the exhaust pipe 15. The gas or air used in the hot blast stove 1 is used for heat recovery treatment of the hot air discharged from the vertical mill 2. This can not only reduce the combustion load of the hot blast stove 1, improve the combustion efficiency of the hot blast stove 1, and ensure the stability of the temperature and flow of the hot air entering the vertical mill 2, but also the preheated gas enters the hot blast stove 1 for combustion, and the combustion speed is fast, which can effectively reduce the gas consumption, greatly reduce the operating cost of the device, and have a high utilization rate of thermal energy and significant energy-saving effect.

[0013] Furthermore, in order to ensure the hot air temperature generated by the hot blast furnace 1 is stable, a thermostat 16 and a third control valve are sequentially arranged on the hot blast pipe 3 between the second control valve and the first return pipe 10 along the air flow direction, the thermostat 16 is equipped with a second temperature sensor 17, the thermostat 16 is equipped with a make-up air pipe 18, the make-up air valve is installed on the make-up air pipe 18, and an electric heating rod 19 is installed inside the thermostat 16. When in use, the third control valve is opened first, and the second control valve is closed, and the hot blast furnace 1 burns the hot air generated by the combustion. The generated hot air first enters the thermostat 16, and the second temperature sensor 17 first monitors the temperature of the hot air. When the hot air temperature meets the requirements, the second control valve is opened to directly send the hot air into the vertical mill 2. If the temperature of the hot air is higher than the standard temperature, the second control valve is closed, and the air is replenished into the thermostat 16 through the air supply pipe 18. When it is adjusted to the standard temperature, the air is supplied again. If the temperature of the hot air is lower than the standard temperature, the electric heating rod 19 is used to heat the hot air again to the standard temperature before the air is supplied.

[0014] Preferably, the primary dust collector 5 is a bag-type dust collector, and the bag-type dust collector adopts the structure in the prior art.

[0015] Furthermore, the secondary dust collector 6 includes a dust removal box and at least two levels of filter screens 61 installed at intervals in the dust removal box. The filter screens 61 are arranged vertically in the dust removal box. A rotating shaft 62 is installed in the dust removal box through the filter screen 61. A motor 63 connected to the rotating shaft 62 is installed on the outer side of the dust removal box. The motor 63 is a device used in the prior art. The finished product is directly purchased according to the needs of use. Three cleaning plates 64 are evenly distributed on the circumference of the rotating shaft 62 on one side of each level of the filter screen 61. A wire brush in contact with the filter screen is installed on each cleaning plate 64. A plurality of ash collecting hoppers 65 are arranged at the bottom of the dust removal box, and the dust is discharged through the primary dust collector 5. The hot air enters the dust removal box, and after multiple filtrations by the multi-stage filter screen 61, a small amount of dust carried in the hot air can be completely filtered out, thereby reducing the dust content of the hot air. The filtered dust passes through the collection hopper 65 and is filtered. After 61 has been used for a period of time, the dust will clog the filter holes. At this time, turn on the motor 63, and the motor 63 drives the rotating shaft 62 to rotate, thereby driving the cleaning plate 64 and the wire brush to rotate. The wire brush can clean up the dust clogging the filter holes during the rotation process, thereby maintaining the filtering effect of the filter screen 61. In order to achieve a better dust removal effect, preferably, the mesh diameter of the multi-stage filter screen 61 in the dust removal box gradually decreases along the airflow direction.

[0016] Furthermore, in order to improve the utilization rate of hot air heat energy, the waste heat recovery device 12 includes a heat exchange box and a first partition 121 and a second partition 122 vertically installed in the heat exchange box. The first partition 121 and the second partition 122 divide the inner cavity of the heat exchange box into an air inlet cavity 123, a heat exchange cavity 124 and an air outlet cavity 125. The outlet of the second return pipe 11 is connected to the air inlet cavity 123. A baffle 127 is vertically installed at the bottom of the heat exchange cavity 124. The baffle 127 is provided at the bottom of the heat exchange cavity 124. 7 and the top of the heat exchange chamber 124 leave a gap, a plurality of heat exchange tubes 126 are installed between the first baffle 121, the baffle 127 and the second baffle 122, the air inlet pipe 13 is arranged at the bottom of the heat exchange box between the second baffle 122 and the baffle 127, the air outlet pipe 14 is arranged at the bottom of the heat exchange box between the baffle 127 and the first baffle 121, and the smoke exhaust pipe 15 is arranged at the top of the air outlet chamber 125. When the smoke is discharged from the secondary dust collector 6 After the hot air enters the air inlet chamber 123, it will enter the multiple heat exchange tubes 126. At this time, the gas or air required for combustion of the hot blast furnace 1 will enter the heat exchange chamber 124 and absorb the heat of the hot air. After the action of the baffle 127, the gas or natural gas flows in the heat exchange chamber 124 in a curved manner. The flow time of the curved flow is long, and the contact time with the hot air is long, which can extend the heat exchange time and absorb most of the heat energy in the hot air. The gas or air after absorbing the heat energy will enter the burner of the hot blast furnace 1 for combustion, which can effectively improve the combustion efficiency. The cooled hot air is discharged from the other end of the heat exchange tube 126 into the air outlet chamber 125, and finally discharged through the smoke exhaust pipe 15. In order to improve the heat exchange efficiency of the heat exchange tube 126, preferably, the heat exchange tube 126 is a corrugated tube or a finned tube. The corrugated tube and the finned tube are existing technologies, and the finished products can be directly purchased on the market according to the specifications required for use.

Claims

1. A hot air reflux device for producing and processing slag micro powder, comprising a hot air stove (1), a vertical mill (2) and a hot air pipe (3) installed between the hot air stove (1) and the vertical mill (2), characterized in that: An exhaust duct (4) is arranged at the top of the vertical mill (2). A primary dust collector (5), a secondary dust collector (6), an induced draft fan (7), a first temperature sensor (8) and a three-way joint (9) are sequentially installed on the exhaust duct (4) along the air flow direction. One outlet of the three-way joint (9) is connected to a first return pipe (10) connected to the hot air pipe (3). A first control valve is installed on the first return pipe (10). A second control valve is installed on the hot air pipe (3) between the first return pipe (10) and the hot air furnace (1). The other outlet of the three-way joint (9) is connected to a second return pipe (11). A waste heat recovery device (12) is arranged at the outlet of the second return pipe (11). An air inlet pipe (13), an air outlet pipe (14) and a smoke exhaust pipe (15) are respectively arranged on the waste heat recovery device (12). The air outlet pipe (14) is connected to the burner of the hot air furnace (1).

2. The hot air reflux device for producing and processing slag micropowder according to claim 1, characterized in that: A thermostat (16) and a third control valve are sequentially arranged on the hot air pipe (3) between the second control valve and the first return pipe (10) along the air flow direction.

3. The hot air reflux device for producing and processing slag micropowder according to claim 2, characterized in that: The thermostat (16) is provided with a second temperature sensor (17), the thermostat (16) is provided with an air supply pipe (18), an air supply valve is installed on the air supply pipe (18), and an electric heating rod (19) is installed inside the thermostat (16).

4. The hot air reflux device for producing and processing slag micropowder according to claim 1, characterized in that: The primary dust collector (5) is a bag-type dust collector.

5. The hot air reflux device for producing and processing slag micropowder according to claim 1, characterized in that: The secondary dust collector (6) comprises a dust removal box and at least two levels of filter screens (61) installed at intervals in the dust removal box. The filter screens (61) are arranged vertically in the dust removal box. A rotating shaft (62) is installed in the dust removal box and passes through the filter screen (61). A motor (63) connected to the rotating shaft (62) is installed on the outer side of the dust removal box. Three cleaning plates (64) are evenly distributed on the circumference of the rotating shaft (62) on one side of each level of the filter screen (61). A wire brush in contact with the filter screen is installed on each cleaning plate (64). A plurality of ash collecting hoppers (65) are arranged at the bottom of the dust removal box.

6. The hot air reflux device for producing and processing slag micropowder according to claim 5, characterized in that: The mesh diameter of the multi-stage filter screen (61) in the dust removal box gradually decreases along the airflow direction.

7. The hot air reflux device for producing and processing slag micropowder according to claim 1, characterized in that: The waste heat recovery device (12) comprises a heat exchange box and a first partition (121) and a second partition (122) vertically installed in the heat exchange box, wherein the first partition (121) and the second partition (122) divide the inner cavity of the heat exchange box into an air inlet cavity (123), a heat exchange cavity (124) and an air outlet cavity (125), the outlet of the second return pipe (11) is connected to the air inlet cavity (123), and a baffle (127) is vertically installed at the bottom of the heat exchange cavity (124), and the baffle (127) is connected to the heat exchange cavity (125). A gap is left at the top of the cavity (124); a plurality of heat exchange tubes (126) are installed through the first partition (121), the baffle (127) and the second partition (122); the air inlet pipe (13) is arranged at the bottom of the heat exchange box between the second partition (122) and the baffle (127); the air outlet pipe (14) is arranged at the bottom of the heat exchange box between the baffle (127) and the first partition (121); and the smoke exhaust pipe (15) is arranged at the top of the air outlet cavity (125).

8. The hot air reflux device for producing and processing slag micropowder according to claim 7, characterized in that: The heat exchange tube (126) is a corrugated tube or a finned tube.

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