Blast furnace slag granulation steam treatment system

Abstract

The utility model belongs to the field of blast furnace ironmaking, and particularly relates to a blast furnace slag granulation steam treatment system. Comprising a blast furnace slag granulation system, a cyclone, a water slag granulation steam portrait system, a heat recovery system and a hot water system, the granulating slag granulating steam portrait system is characterized in that a granulating tower (3) is connected with a cyclone (4), the cyclone (4) is connected with an evaporator (6), the evaporator (6) is connected with a gas-water separator (10), and the gas-water separator (10) is connected with an exhaust fan (11); the heat recovery system is characterized in that an evaporator (6) is connected with a compressor (7), a condenser (8), a pressure reducing valve (9) and the evaporator (6) in sequence; and the condenser (8) is sequentially connected with a hot water user (14) and the condenser (8). The device has the advantages that the steam generated in the blast furnace slag granulation process is cooled by the evaporator and condensed, white smoke plume during emission is eliminated, and sensible heat and latent heat of vaporization of the steam are recycled.

Description

Technical Field

[0001] The utility model belongs to the field of blast furnace ironmaking, and specifically relates to an environmental protection and waste heat utilization technology. Background Art

[0002] The blast furnace is the core equipment of iron and steel enterprises. During the ironmaking process, the temperature of the molten slag generated is about 1500 °C. Currently, the slag treatment system of blast furnaces generally uses water cooling to cool the blast furnace slag. During the water cooling process, a large amount of steam is generated and discharged into the atmosphere through the granulation tower. During this process, about 40% of the heat of the high-temperature slag is carried away in the form of slag flushing steam, and the temperature of the steam mixed with air is about 80 °C. Some of the steam will condense to form water mist in the chimney, and the obvious white water mist at the outlet of the granulation tower seriously affects the clean and environmentally friendly image of the blast furnace;

[0003] The slag flushing steam has very rich waste heat resources. Direct external discharge not only wastes precious water resources, but also wastes a large amount of heat, and generates a large amount of white mist. Since the steam contains a large amount of acidic substances, it also pollutes the environment. The traditional treatment method is to use water spray to condense the steam, recover the condensed water for recycling, but this method has a large water consumption, and a large amount of waste heat resources in the steam are still not recovered. Since the slag discharge from blast furnace ironmaking is intermittent and the water quenched slag is also discontinuous, using conventional methods to eliminate white mist and solve environmental protection problems requires a very large investment. Currently, there is no mature technology for promoting the application of blast furnace slag flushing steam whitening elimination in the domestic and foreign iron and steel industries. If a reasonable method cannot be used to utilize the slag flushing steam, it will inevitably lead to prominent environmental problems in iron and steel enterprises. Therefore, adopting a reasonable method to combine the high-humidity steam discharged by iron and steel enterprises with heat supply is another reasonable and effective way to reduce energy waste, improve energy utilization rate, and improve the economic benefits of enterprises.

[0004] Chinese Patent Publication No. CN214115590, with a publication date of September 03, 2021, discloses a slag flushing water tank. The slag flushing water tank includes a water tank body, and the inlet of the water tank body is connected to the granulation tower. Among them, a slag cleaner, a water-water heat exchanger, a packing filter layer, a spray layer, and a steam-water heat exchanger are sequentially arranged in the water tank body from bottom to top; the slag flushing water tank further includes a steam absorption device, and the steam absorption device is connected to the water tank body and / or the granulation tower. The steam absorption device includes: an absorption housing, and a packing layer, a spray layer, and a dehydration layer are arranged in the absorption housing. This utility model comprehensively and efficiently recovers the heat of the slag flushing water and steam generated by slag granulation through the water-water heat exchanger, packing filter layer, spray layer, steam-water heat exchanger and steam absorption device in the water tank body, and recovers the steam condensate. This slag flushing water tank requires a large amount of cooling water to cool and absorb the steam to achieve the purpose of utilizing waste heat, and has a large demand for water, and its application scenario is limited.

[0005] Chinese Patent Publication No. CN202311428280.1, with a publication date of January 26, 2024, discloses a device and method for disinfection and white smoke elimination of a granulation tower, belonging to the field of blast furnace slag treatment. The device for disinfection and white smoke elimination of the granulation tower of the present invention includes a chimney section above the granulation tower, a rectification area, a disinfection area, and a heating area that are connected in sequence from bottom to top. The steam is rectified by arranging a rectification area in the middle and lower part of the chimney section of the granulation tower, and the rectified steam enters the disinfection area for disinfection. The disinfected steam enters the heating area, and the original steam is heated by introducing superheated steam into the heating area, thereby achieving the effect of white smoke elimination. This patent does not solve the problem of utilization of the waste heat of the steam generated by slag granulation. Summary of the Invention

[0006] The purpose of the present utility model is to provide a blast furnace slag granulation steam treatment system to solve the problems of steam emission and utilization of waste heat of steam during the granulation process of blast furnace slag.

[0007] The present utility model is realized through the following technical solutions:

[0008] During the blast furnace smelting process, a large amount of high-temperature liquid slag is discharged. The slag is discharged out of the furnace through the slag notch or the iron notch, flows into the granulation tower through the slag trench, and is impacted by the high-speed water flow of the flushing box after flowing out of the slag trench, and is water-quenched into vitreous granulated slag. A large amount of steam is generated during the slag granulation process, and part of the air enters from the inlet of the granulation tower and mixes into the steam to form an air-steam mixed gas above 80°C, which is simply called steam.

[0009] The blast furnace slag granulation steam treatment system includes a blast furnace slag granulation system, a cyclone, a water slag granulation steam white smoke elimination system, a heat recovery system, and a hot water system;

[0010] The water slag granulation steam white smoke elimination system is: the granulation tower is connected to the cyclone, the cyclone is connected to the evaporator, the evaporator is connected to the gas-liquid separator, and the gas-liquid separator is connected to the induced draft fan;

[0011] The heat recovery system is: the evaporator is sequentially connected to the compressor, the condenser, the pressure reducing valve, and the evaporator; the condenser is sequentially connected to the hot water user and the condenser.

[0012] The blast furnace slag granulation steam treatment system is characterized in that the blast furnace slag granulation system includes blast furnace slag, a flushing box, and a granulation tower;

[0013] The water slag granulation steam white smoke elimination system is: the steam generated by blast furnace slag granulation enters the cyclone, the steam-water mixture discharged from the cyclone enters the evaporator to cool down, and then the condensed water is removed by the gas-liquid separator, and then is discharged into the atmosphere through the induced draft fan. The slag, slag wool, and water removed by the cyclone are discharged into the water slag pond through the screw conveyor.

[0014] Preferably, the heat recovery agent used in the heat recovery system is R417a, or R410a, or R22.

[0015] Preferably, the heat recovery system is such that the outlet water of the hot water user (14) is connected to the inlet water of the condenser (8), and the outlet water of the condenser (8) is connected to the inlet water of the hot water user (14).

[0016] Preferably, the hot water user 14 is a heating user or a refrigeration user.

[0017] The beneficial effects of the present utility model are as follows: The steam generated during the granulation process of blast furnace slag is cooled and condensed by the evaporator, eliminating the white plume during emission, and the sensible heat and latent heat of vaporization of the steam are recovered and utilized. Description of the Drawings

[0018] Figure 1 is a flow chart of the blast furnace slag granulation steam treatment system

[0019] Legend Marks

[0020] 1 Blast furnace slag, 2 Flushing box, 3 Granulation tower, 4 Cyclone, 5 Slag pond, 6 Evaporator, 7 Compressor, 8 Condenser, 9 Pressure reducing valve, 10 Gas-water separator, 11 Exhaust fan, 12 Screw conveyor, 13 Slag discharge port, 14 Hot water user. Specific Embodiments

[0021] Embodiment 1:

[0022] The following takes the attached Figure 1 as a reference to describe the implementation of the present invention in detail so that those of ordinary skill in the art can easily implement it. The present invention can be embodied in many different forms and is not limited to this description.

[0023] During the blast furnace smelting process, a large amount of high-temperature liquid blast furnace slag 1 is discharged. The temperature of the blast furnace slag 1 is about 1500 °C. The blast furnace slag 1 is discharged out of the furnace through the slag notch or the tuyere and flows into the granulation tower through the slag ditch. After the blast furnace slag 1 flows out of the slag ditch, it is impacted by the high-speed water flow of the flushing box 2 and is water-quenched into glassy granulated slag. A large amount of steam is generated during the granulation process of the blast furnace slag 1. Part of the air enters from the inlet of the granulation tower 3 and is mixed into the steam to form an air-steam mixture gas above 80 °C, simply referred to as steam.

[0024] The blast furnace slag 1 is granulated by the high-speed water flow of the flushing box 2 in the granulation tower 3, forming granulated slag and steam. Some slag particles and slag wool are carried in the steam. The slag particles, slag wool and part of the water in the steam are removed by the cyclone 4. Then the steam enters the evaporator 6. After heat exchange in the evaporator 6, the temperature drops from about 80 °C to about 50 °C. Then, the condensed water is removed by the gas-liquid separator 10. The remaining air after removing the condensed water is discharged into the atmosphere by the exhaust fan 11. The granulated slag is discharged from the slag discharge port 13 of the granulation tower 3 and flows into the slag pond 5 through the slag ditch. The slag particles, slag wool and part of the water removed from the steam by the cyclone 4 are sent to the slag pond 5 by the screw conveyor 12. After the slag precipitates in the slag pond, it is fished out by the grab crane. The granulated slag is used in the building materials industry.

[0025] The steam at about 80 °C enters the evaporator 6 and the temperature drops to about 50 °C. The sensible heat and latent heat of vaporization of the steam heat the heat recovery agent. The heat recovery agent is R417a. After being heated, the heat recovery agent vaporizes. After being pressurized by the compressor 7, the temperature of the heat recovery agent rises to about 200 °C. Then the heat recovery agent enters the condenser 8, transfers the heat to the water, and the heat recovery agent condenses. After passing through the pressure reducing valve 9, it is further cooled. The cooled heat recovery agent then enters the evaporator 6 to exchange heat with the steam, and the system operates in a cycle.

[0026] The water discharged from the hot water user 14 enters the condenser 8 and exchanges heat with the heat recovery agent. The water is heated to above 80 °C after passing through the condenser 8. The heated hot water is then sent back to the hot water user 14, and the system operates in a cycle. The hot water user 14 uses the hot water for heating or refrigeration.

[0027] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A blast furnace slag granulation steam treatment system, characterized in that: Including blast furnace slag granulation system, cyclone, water slag granulation steam Xiaobai system, heat recovery system, hot water system; The water slag granulation steam desulphurization system comprises: a granulation tower (3) and a cyclone (4), the cyclone (4) is connected to an evaporator (6), the evaporator (6) is connected to a gas-water separator (10), and the gas-water separator (10) is connected to an exhaust fan (11); The heat recovery system is as follows: the evaporator (6) is connected in sequence with the compressor (7), the condenser (8), the pressure reducing valve (9), and the evaporator (6); and the condenser (8) is connected in sequence with the hot water user (14) and the condenser (8).

2. A blast furnace slag granulation steam treatment system according to claim 1, characterized in that: The blast furnace slag granulation system comprises blast furnace slag (1), a punching box (2) and a granulation tower (3).

3. A blast furnace slag granulation steam treatment system according to claim 1, characterized in that: The slag, slag wool and water removed by the cyclone (4) are discharged into the water-slag pool (5) via a screw conveyor (12).

4. A blast furnace slag granulation steam treatment system according to claim 1, characterized in that: The heat recovery agent used in the heat recovery system is R417a, or R410a, or R22.

5. A blast furnace slag granulation steam treatment system according to claim 1, characterized in that: The heat recovery system is such that the water outlet of the hot water user (14) is connected to the water inlet of the condenser (8), and the water outlet of the condenser (8) is connected to the water inlet of the hot water user (14).

6. A blast furnace slag granulation steam treatment system as claimed in claim 5, characterized in that: The hot water user (14) is a heating user or a cooling user.

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