A high-temperature water slag flushing exhaust steam energy-saving water collecting and pollutant treatment system and method

Abstract

This invention proposes a high-temperature water flushing slag exhaust steam energy-saving water recovery and pollutant treatment system and method. The system includes an elevated granulation tower, a slag flushing water inlet, a high-temperature slag inlet, a liquid collection device, a spray device, a mixed air heating zone, a mixed gas induced draft fan, a slag flushing pool, a spray water condensate treatment unit, an exhaust steam bypass condenser, a gas heat source unit, a demister, and a thermometer and hygrometer. The slag flushing pool is connected to the bottom wall of the elevated granulation tower. The spray water condensate treatment unit is connected to the liquid collection device and the spray device. The inlet of the exhaust steam bypass condenser is connected to the tower wall of the elevated granulation tower via an exhaust steam bypass pipe outlet section A1, and the outlet is connected to the inlet of the second demister. The outlet of the second demister is connected to one side of the mixed air heating zone via an exhaust steam bypass pipe return section A2. This system can deeply purify the blast furnace slag flushing exhaust steam, reduce the emission of acidic pollutants such as hydrogen sulfide and sulfur dioxide, realize the recovery and utilization of waste heat from the slag flushing exhaust steam, and greatly reduce the water consumption of the slag flushing system.

Description

[Technical Field]

[0001] This invention relates to the technical field of colored plume purification in the metallurgical industry, and in particular to a high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system and method. [Background Technology]

[0002] In the metallurgical industry, water is commonly used as a cooling medium for the high-temperature slag produced by industrial furnaces such as blast furnaces and converters in steelmaking, and copper smelting furnaces and aluminum melting furnaces in non-ferrous metals. Examples include water quenching of blast furnace slag and hot slag quenching or hot pouring processes for converter slag. Taking blast furnaces as an example, approximately 80% of blast furnace slag is quenched by water. Each ton of pig iron produces about 0.3-0.4 tons of blast furnace slag, and each ton of slag requires approximately 9-10 tons of flushing water. During the contact with the high-temperature slag and during transport to the flushing water pool, the flushing water evaporates a large amount of exhaust steam, carrying away about 40% of the heat from the high-temperature slag (temperature 80-100℃). In 2019, my country's blast furnace pig iron production was 809 million tons, and the approximately 2 billion tons of flushing water not only possessed a large amount of low-temperature waste heat resources but also generated a large amount of low-pressure exhaust steam, dissipating approximately 85 million tons of flushing water. The exhaust steam from blast furnace slag flushing contains large amounts of hydrogen sulfide, sulfur dioxide, hydrogen chloride, fibrous fibers, and ultrafine silicate particles, which have a significant impact on the production environment. Water mist and plumes frequently occur at the production site, endangering the health of employees and causing severe corrosion to equipment and facilities in the blast furnace area. Therefore, comprehensive treatment of blast furnace slag flushing exhaust steam to eliminate white smoke in the blast furnace area, recover large amounts of water resources, improve the environment of the blast furnace area, reduce corrosion of production equipment, and lower pollutant emissions has become an increasingly important issue for enterprises and society.

[0003] For example, patent publication number CN103060494B proposes a steam recovery type blast furnace slag flushing water system. Its key technology uses a spray method to recover the exhaust steam generated at the slag flushing port, but it does not consider plume control and does not recover exhaust steam from the slag flushing water pool. Patent publication number CN208667759U proposes a system for dust removal, dehydration, and whitening in a blast furnace slag granulation tower. Its key technology uses a gas-cooled gas condenser (GGH) to exchange heat with the exhaust steam before and after condensation treatment. However, the GGH equipment has a significant risk of corrosion and fails to completely eliminate visual pollution in winter. Patent publication number CN208883918U proposes a... The key technology of the slag flushing water whitening and waste heat utilization system is to condense and treat the exhaust steam generated in the slag flushing water pool. However, the treatment scope is incomplete and fails to completely eliminate visual pollution. Patent publication number CN209322919U proposes an environmentally friendly whitening treatment and waste heat utilization system for blast furnace slag. Its key technology uses a series of heat exchangers and spray devices to condense and treat the exhaust steam at the slag flushing port and slag flushing water pool. However, the spray system requires a large amount of fresh water and lacks a heating system, thus failing to completely eliminate visual pollution. Patent publication number CN209348354U proposes an integrated whitening device for blast furnace slag flushing flue gas. Its key technology only... Heating the slag and exhaust steam mixture failed to achieve the desired pollutant purification effect; Patent Publication No. CN209910414U proposes a whitening device, the key technology of which is to treat high-temperature and high-humidity flue gas or steam by using a water cooler and an air cooler in series, but the air cooler has a problem of low heat exchange efficiency; Patent Publication No. CN210206387U proposes a self-heating flue gas whitening device, the key technology of which is to set up a reheater and an air cooler in the whitening tower from top to bottom, so that the flue gas is cooled and reheated for whitening without additional heat, but the reheater has a significant risk of corrosion, the air cooler has a large air consumption, and the pipeline layout is too complicated; Application No. 201910944801.6 proposes a device for eliminating whitening and recovering waste heat from blast furnace slag flushing exhaust steam. Its key technology only addresses the condensation treatment of exhaust steam generated at the slag flushing port, resulting in incomplete treatment scope, a large air condensation system, high air consumption, and low heat source quality. Publication No. CN109457065A proposes a waste steam recovery system for blast furnace slag flushing water. Its key technology is the use of a series design of spray and heat exchanger for condensation treatment of exhaust steam from the slag flushing system, which has a good pollutant treatment effect. However, the circulating water used in its spray device and heat exchanger is directly transported to the cooling tower for cooling, resulting in a large waste of low-temperature water resources.

[0004] As can be seen from the above analysis, although the existing technology has provided methods for eliminating whitening of exhaust steam and recovering waste heat in blast furnace slag flushing systems, there are still various defects that need to be improved. It is necessary to develop a relatively complete, energy-efficient, economical and reliable high-temperature water flushing slag flushing exhaust steam energy-saving water recovery and pollutant treatment system and method to meet the treatment needs of blast furnace water flushing slag flushing systems. [Summary of the Invention]

[0005] The purpose of this invention is to solve the problems in the prior art and propose a high-temperature water flushing slag exhaust steam energy-saving water recovery and pollutant treatment system and method. It is applicable to the treatment of steam generated by high-temperature slag treatment systems such as blast furnaces, converters, and aluminum melting furnaces. It is particularly suitable for the comprehensive treatment of exhaust steam generation parts such as blast furnace slag flushing openings and slag flushing water pools. It can deeply purify blast furnace slag flushing exhaust steam, reduce the emission of acidic pollutants such as hydrogen sulfide and sulfur dioxide, realize the recovery and utilization of waste heat from slag flushing exhaust steam, and greatly reduce the water consumption of the slag flushing system.

[0006] To achieve the above objectives, this invention proposes a high-temperature water flushing slag and exhaust steam energy-saving water collection and pollutant treatment system, comprising a high-altitude granulation tower, a flushing water inlet, a high-temperature slag inlet, a spray device, a mixed air heating zone, and a mixed gas induced draft fan arranged sequentially from bottom to top on the tower body of the high-altitude granulation tower; it also includes a flushing tank, a spray water condensate treatment unit, an exhaust steam bypass condenser, a gas heat source unit, and a second demister; the spray water condensate treatment unit is connected to the spray device and provides spray water to the spray device through a spray water pipe; the flushing tank is connected to the bottom wall of the high-altitude granulation tower through a slag water ditch C, and the top side wall of the flushing tank is connected to the tower wall of the high-altitude granulation tower through a steam return pipe D; the exhaust steam... The inlet of the bypass condenser is connected to the wall of the high-altitude granulation tower via the exhaust steam bypass pipe outlet section A1, with the connection point located above the spray device. The outlet of the exhaust steam bypass condenser is connected to the inlet of the second demister, and the outlet of the second demister is connected to the inlet of the exhaust steam bypass pipe return section A2 via a reducer. The outlet of the exhaust steam bypass pipe return section A2 is connected to the wall of the high-altitude granulation tower, with the connection point located on one side of the mixed air heating area. The gas heat source unit is connected to the wall of the high-altitude granulation tower via the gas heat source pipe B, with the connection point located on the other side of the mixed air heating area, specifically opposite the connection point of the exhaust steam bypass pipe return section. The mixed gas induced draft fan is located at the outlet of the mixed air heating area.

[0007] Preferably, the spray water condensate treatment unit includes a filter, a buffer tank, a conditioning device, a circulating pump, and a heat recovery unit. A liquid collection device, either a liquid collection tray or a steam riser liquid collection pan, is located below the spray device. The filter inlet is connected to the liquid collection device outlet via a spray water pipe, and the filter outlet is connected to the buffer tank inlet via a spray water pipe. The conditioning device is connected to the top of the buffer tank via an alkali agent pipe F. The bottom of the buffer tank is connected to the slag flushing pool via a condensate recovery pipe E. A movable sealing cover is installed above the slag flushing pool. The circulating pump inlet is connected to the buffer tank below the liquid level via a spray water pipe, and the circulating pump outlet is connected to the heat recovery unit's heat medium inlet via a spray water pipe. The heat recovery unit's heat medium outlet is connected to the spray device's spray water inlet via a spray water pipe. The heat exchange tubes of the heat recovery unit and the exhaust steam bypass condenser are made of fluoroplastics with a diameter of 10–14 mm and a wall thickness of 0.8–1 mm, arranged in a U-shape.

[0008] Preferably, a first demister is provided between the high-temperature slag inlet and the spraying device, and the first demister is located above the connection between the steam reflux pipe D and the high-altitude granulation tower; a third demister is provided between the spraying device and the mixed air heating area, and the third demister is located above the connection between the exhaust steam bypass pipe outlet section A1 and the high-altitude granulation tower; the first demister, the second demister and the third demister are all of no less than two layers and are of the ridge type.

[0009] Preferably, the device also includes a first thermometer and hygrometer, a second thermometer and hygrometer, and a third thermometer and hygrometer for real-time monitoring of the slag flushing steam temperature. The first thermometer and hygrometer are located between the first demister and the liquid collection device, the second thermometer and hygrometer are located above the spray device, and the third thermometer and hygrometer are located at the outlet of the second demister.

[0010] Preferably, the spraying device has no less than three spraying layers, which are set in the middle of the high-altitude granulation tower. The spacing between the spraying layers is 3 to 5 m. Multiple nozzles are evenly arranged on each spraying layer, and the nozzles on two adjacent spraying layers are arranged in an alternating manner.

[0011] Preferably, the cooling medium 'a' in both the heat recovery unit and the exhaust steam bypass condenser is low-temperature water, preferably blast furnace wall cooling water. The inlets of the cooling medium 'a' in both the heat recovery unit and the exhaust steam bypass condenser are connected in sequence to the cooling medium delivery pump and the first makeup water tank via pipelines, and the outlets of the cooling medium 'a' are connected to the water inlet of the blast furnace wall cooling system via pipelines. Alternatively, the cooling medium 'a' in both the heat recovery unit and the exhaust steam bypass condenser can be low-temperature air. The inlets of the cooling medium 'a' in both the exhaust steam bypass condenser and the heat recovery unit are connected to the blower via pipelines, and the outlets of the cooling medium 'a' are connected to the air inlet of the hot blast stove via pipelines.

[0012] Preferably, a first electrically operated louvered valve is provided between the third demister and the air mixing and heating zone; a second electrically operated louvered valve is provided on the exhaust steam bypass pipe outlet section A1; and a third electrically operated louvered valve is provided on the exhaust steam bypass pipe return section A2. When the first electrically operated louvered valve is closed and the second and third electrically operated louvered valves are opened, the spraying device and the exhaust steam bypass condenser operate in series. When the first electrically operated louvered valve is opened and the second and third electrically operated louvered valves are closed, the spraying device operates independently. The high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system can be flexibly switched according to different climatic conditions such as winter, summer, sunny weather, and extreme weather.

[0013] Preferably, the exhaust steam bypass pipe outlet section A1 and the exhaust steam bypass pipe return section A2 are arranged at an inclination or horizontal angle, with the inclination angle not exceeding 30°, so that the condensate condensed and precipitated by the exhaust steam bypass condenser can flow from top to bottom into the liquid collection device.

[0014] Preferably, the gas heat source unit is a dust removal system for the blast furnace tapping area or a hot blast stove assembly.

[0015] Preferably, the system also includes a slag flushing water replenishment tank. The spray water condensate treatment unit may also include a conditioning device, a circulating pump, and a second replenishment tank. The second replenishment tank is connected to the inlet of the spray device via the circulating pump to provide spray water to the spray device. The conditioning device is connected to the top of the second replenishment tank via an alkali agent pipeline F.

[0016] This invention also proposes a high-temperature water flushing method for slag exhaust steam energy-saving water recovery and pollutant treatment, comprising the following steps:

[0017] S1. High-temperature slag from the high-temperature slag inlet and flushing water from the flushing water inlet are flushed at the bottom of the high-altitude granulation tower to generate high-temperature flushing exhaust steam; the slag-water mixture is transported to the flushing water pool through the slag-water ditch C, and the high-temperature flushing exhaust steam generated in the flushing water pool is returned to the bottom of the high-altitude granulation tower through the exhaust steam return pipe D under the sealing action of the moving sealing cover.

[0018] S2. The high-temperature exhaust steam generated at the bottom of the high-altitude granulation tower migrates upward along the tower body and enters the first demister for a demisting operation.

[0019] S3. The high-temperature slag flushing exhaust steam from the first demister continues to migrate upward along the high-altitude granulation tower body and enters the spray device for primary condensation operation. The spray water and condensate are collected in the liquid collection tray.

[0020] S4. With the first electric louvered valve closed and the second and third electric louvered valves open, the slag-flushing exhaust steam from the spray device migrates along the exhaust steam bypass pipe outlet section A1, enters the exhaust steam bypass condenser for secondary condensation, and after condensing to the set temperature, enters the second demister for secondary demisting, and then migrates along the exhaust steam bypass pipe return section A2 to be transported back to the mixing and heating area at the top of the high-altitude granulation tower; the condensate flows from top to bottom along the exhaust steam bypass pipe outlet section A1 and collects in the liquid collection tray.

[0021] S5. With the first electric louvered valve open and the second and third electric louvered valves closed, the slag-flushing exhaust steam from the spray device continues to migrate upward along the high-altitude granulation tower body, enters the third demister for secondary demisting, and then passes through the first electric louvered valve before entering the mixing and heating zone.

[0022] S6. The spray water and condensate in the collection tray enter the spray water and condensate treatment unit through pipelines, and after passing through the filter, they enter the buffer water tank. The conditioning device inputs alkali agent into the buffer water tank through the alkali agent pipeline F to carry out conditioning operation, so that the spray water is weakly alkaline, so as to remove acidic pollutants contained in the slag flushing exhaust steam more efficiently during the spray cooling process. The condensate after conditioning is transported back to the slag flushing water tank through the condensate recovery pipeline E for water replenishment operation. The conditioned spray water is then transported back to the spray device for waste heat recovery operation through the circulating pump and heat recovery unit, and then transported back for recycling.

[0023] S7. The heat source from the gas heat source unit enters the mixing and heating area through the gas heat source pipeline B, and mixes with the slag flushing exhaust gas after condensation and purification to form an unsaturated hot mixed gas; the mixed gas continues to migrate upward along the tower body of the high-altitude granulation tower under the action of the mixed gas induced draft fan, and is discharged through the outlet of the high-altitude granulation tower without visual pollution.

[0024] S8. The first water tank delivers the cold medium a required for condensing the slag flushing exhaust steam to the heat recovery unit and the exhaust steam bypass condenser through the cold medium transfer pump. The heated cold medium a is then transported through pipeline to the water inlet of the blast furnace wall cooling system to realize the recycling of the cold medium.

[0025] S9. The first thermometer, the second thermometer, and the third thermometer are used to monitor in real time the condensation of the slag flushing exhaust steam to a set temperature; the set temperature is the temperature corresponding to a 50% reduction in the moisture content of the slag flushing exhaust steam.

[0026] The beneficial effects of this invention are:

[0027] 1. This invention is a complete treatment system and method for the slag flushing outlet, slag flushing water pool and other areas where slag flushing exhaust steam is generated, overcoming the shortcomings of the existing technology in terms of incomplete treatment scope;

[0028] 2. This invention achieves both deep condensation treatment of slag flushing exhaust steam and complete elimination of visual pollution by using a spray device, an exhaust steam bypass condenser, and mixed air reheating, thus solving environmental problems.

[0029] 3. This invention can realize the series condensation operation of the spray device and the exhaust steam bypass condenser or the independent condensation operation of the spray device through the control of the electric louvered valve, thereby realizing flexible switching of different climatic conditions such as winter, summer, sunny weather, and extreme weather.

[0030] 4. This invention uses an alkaline conditioning treatment unit to treat the spray water with spray water condensate, which can effectively prevent acid corrosion of pipelines and effectively promote the treatment of acidic pollutants such as hydrogen sulfide, sulfur dioxide, and hydrogen chloride in the slag flushing exhaust steam by spray water, thereby reducing pollutant emissions. At the same time, it can effectively collect condensate and reduce water consumption in the slag flushing system.

[0031] 5. This invention utilizes blast furnace wall cooling water or low-temperature air as a cooling medium to effectively recover the low-grade waste heat from slag flushing exhaust steam.

[0032] 6. This invention makes full use of the existing heat source gas in the blast furnace area, namely the hot flue gas discharged from the dust removal system of the blast furnace tapping area, or the hot flue gas discharged from the hot blast stove components, as the reheat heat source for the condensed slag flushing exhaust steam, and the reheating process does not add energy consumption.

[0033] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. [Attached Image Description]

[0034] Figure 1 This is a system diagram of the high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system in Example 1.

[0035] Figure 2 This is a system diagram of the high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system in Example 2.

[0036] Figure 3 This is a system diagram of the high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system in Example 3.

[0037] In the diagram: 1-High-altitude granulation tower, 2-Slag flushing water inlet, 3-High-temperature slag inlet, 41-First demister, 42-Second demister, 43-Third demister, 51-First thermometer and hygrometer, 52-Second thermometer and hygrometer, 53-Third thermometer and hygrometer, 6-Liquid collection tray, 7-Spraying device, 81-First electric louvered valve, 82-Second electric louvered valve, 83-Second electric louvered valve, 9-Mixed air heating zone, 10-Mixed gas induced draft fan, 11-Slag flushing water tank, 12-Transfer... Dynamic sealing cover, 13-spray water condensate treatment unit, 131-filter, 132-buffer water tank, 133-conditioning device, 134-circulating pump, 135-heat recovery unit, 136-second makeup water tank, 14-exhaust steam bypass condenser, 15-gas heat source unit, 16-cold medium transfer pump, 17-first makeup water tank, 18-blast furnace wall cooling system, 19-steam collection tray, 191-center baffle, 192-lower tray, 20-blower fan, 21-hot blast stove air inlet;

[0038] A1 - Exhaust steam bypass pipeline outlet section, A2 - Exhaust steam bypass pipeline return section, B - Gas heat source pipeline, C - Slag water ditch, D - Exhaust steam return pipeline, E - Condensate recovery pipeline, F - Alkali agent pipeline.

[0039] a-Cold medium.

Detailed Implementation Methods

[0040] Example 1

[0041] See Figure 1This invention discloses a high-temperature water flushing slag and exhaust steam energy-saving water collection and pollutant treatment system, comprising a high-altitude granulation tower 1, a flushing water inlet 2, a high-temperature slag inlet 3, a spray device 7, a mixed air heating zone 9, and a mixed air induced draft fan 10 arranged sequentially from bottom to top on the tower body of the high-altitude granulation tower 1; it also includes a flushing tank 11, a spray water condensate treatment unit 13, an exhaust steam bypass condenser 14, a gas heat source unit 15, and a second demister 42; the spray water condensate treatment unit 13 is connected to the spray device 7 and provides spray water to the spray device 7 through a spray water pipe; the flushing tank 11 is connected to the bottom tower wall of the high-altitude granulation tower 1 through a slag water ditch C, and the top side wall of the flushing tank 11 is connected to the tower wall of the high-altitude granulation tower 1 through a steam return pipe D; the exhaust steam bypass... The inlet of condenser 14 is connected to the tower wall of high-altitude granulation tower 1 via exhaust steam bypass pipe outlet section A1, with the connection point located above spray device 7. The outlet of the exhaust steam bypass condenser 14 is connected to the inlet of the second demister 42, and the outlet of the second demister 42 is connected to the inlet of exhaust steam bypass pipe return section A2 via a reducer. The outlet of the exhaust steam bypass pipe return section A2 is connected to the tower wall of high-altitude granulation tower 1, with the connection point located on one side of the mixed air heating zone 9. The gas heat source unit 15 is connected to the tower wall of high-altitude granulation tower 1 via gas heat source pipe B, with the connection point located on the other side of the mixed air heating zone 9, specifically opposite the connection point of the exhaust steam bypass pipe return section A2. The mixed gas induced draft fan 10 is located at the outlet of the mixed air heating zone 9.

[0042] Furthermore, the spray water condensate treatment unit 13 includes a filter 131, a buffer tank 132, a conditioning device 133, a circulating pump 134, and a heat recovery unit 135. A liquid collection device is provided below the spray device 7. The inlet of the filter 131 is connected to the outlet of the liquid collection device through a spray water pipe, and the outlet of the filter 131 is connected to the inlet of the buffer tank 132 through a spray water pipe. The conditioning device 133 is connected to the top of the buffer tank 132 through an alkali agent pipe F, and the bottom of the buffer tank 132 is connected to the slag flushing device through a condensate recovery pipe E. A water tank 11 is connected, and a movable sealing cover 12 is installed above the slag flushing tank 11. The inlet of the circulating pump 134 is connected to the buffer water tank 132 below the liquid level through a spray water pipe. The outlet of the circulating pump 134 is connected to the heat medium inlet of the heat recovery unit 135 through a spray water pipe. The heat medium outlet of the heat recovery unit 135 is connected to the spray water inlet of the spray device 7 through a spray water pipe. The heat exchange tubes of the heat recovery unit 135 and the exhaust steam bypass condenser 14 are all fluoroplastics. The diameter of the fluoroplastic tubes is 10-14 mm, the wall thickness is 0.8-1 mm, and they are arranged in a U-shape.

[0043] Furthermore, the liquid collection device is a liquid collection tray 6, the outer diameter of which is smaller than the inner diameter of the high-altitude granulation tower 1. There is a gap between the outer side of the liquid collection tray 6 and the inner wall of the high-altitude granulation tower 1 for the upward migration of slag-flushing steam. The bottom of the liquid collection tray 6 has a discharge pipe, and the outlet of the discharge pipe is connected to the filter 131.

[0044] Furthermore, a first demister 41 is provided between the high-temperature slag inlet 3 and the spray device 7. The first demister 41 is located above the connection between the steam reflux pipe D and the high-altitude granulation tower 1. A third demister 43 is provided between the spray device 7 and the mixed air heating zone 9. The third demister 43 is located above the connection between the exhaust steam bypass pipe outlet section A1 and the high-altitude granulation tower 1. The first demister 41, the second demister 42, and the third demister 43 are all of no less than two layers and are of the ridge type.

[0045] Furthermore, it also includes a first thermo-hygrometer 51, a second thermo-hygrometer 52, and a third thermo-hygrometer 53 for real-time monitoring of the slag flushing steam temperature. The first thermo-hygrometer 51 is located between the first demister 41 and the liquid collection tray 6, the second thermo-hygrometer 52 is located above the spray device 7, and the third thermo-hygrometer 53 is located at the outlet of the second demister 42.

[0046] Furthermore, the spraying device 7 has no less than three spraying layers, which are set in the middle of the high-altitude granulation tower 1. The spacing between the spraying layers of the spraying device 7 is 3 to 5 m. Multiple nozzles are evenly arranged on each spraying layer, and the nozzles on two adjacent spraying layers are staggered.

[0047] Furthermore, the cooling medium a of the heat recovery unit 135 and the exhaust steam bypass condenser 14 is low-temperature water, preferably blast furnace wall cooling water. The inlets of the cooling medium a of the heat recovery unit 135 and the exhaust steam bypass condenser 14 are connected to the cooling medium transfer pump 16 and the first makeup water tank 17 in sequence through pipelines, and the outlets of the cooling medium a are connected to the water inlet of the blast furnace wall cooling system 18 through pipelines.

[0048] Furthermore, a first electrically operated louvered valve 81 is provided between the third demister 43 and the mixed air heating zone 9; a second electrically operated louvered valve 82 is provided on the exhaust steam bypass pipe outlet section A1; and a third electrically operated louvered valve 83 is provided on the exhaust steam bypass pipe return section A2. When the first electrically operated louvered valve 81 is closed and the second electrically operated louvered valve 82 and the third electrically operated louvered valve 83 are opened, the spray device 7 and the exhaust steam bypass condenser 14 operate in series. When the first electrically operated louvered valve 81 is opened and the second electrically operated louvered valve 82 and the third electrically operated louvered valve 83 are closed, the spray device 7 operates independently. The high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system can be flexibly switched according to different climatic conditions such as winter, summer, sunny weather, and extreme weather.

[0049] Furthermore, the exhaust steam bypass pipe outlet section A1 and the exhaust steam bypass pipe return section A2 are arranged at an inclination or horizontal angle, with an inclination angle not exceeding 30°, so that the condensate condensed and precipitated by the exhaust steam bypass condenser 14 can flow from top to bottom into the liquid collection tray 6.

[0050] Furthermore, the gas heat source unit 15 is a dust removal system for the blast furnace tapping area or a hot blast stove component.

[0051] A method for energy-saving water recovery and pollutant treatment of high-temperature water flushing slag exhaust steam includes the following steps:

[0052] S1. High-temperature slag from high-temperature slag inlet 3 and flushing water from flushing water inlet 2 are flushed at the bottom of the high-altitude granulation tower 1 to generate high-temperature flushing exhaust steam; the slag-water mixture is transported to the flushing water pool 11 through the slag-water ditch C, and the high-temperature flushing exhaust steam generated in the flushing water pool 11 is returned to the bottom of the high-altitude granulation tower 1 through the exhaust steam return pipe D under the sealing action of the movable sealing cover 12.

[0053] S2. The high-temperature slag flushing exhaust steam generated at the bottom of the high-altitude granulation tower 1 migrates upward along the tower body of the high-altitude granulation tower 1 and enters the first demister 41 for a demisting operation;

[0054] S3. The high-temperature slag flushing exhaust steam from the first demister 41 continues to migrate upward along the tower body of the high-altitude granulation tower 1 and enters the spray device 7 for primary condensation operation. The spray water and condensate are collected in the liquid collection tray 6.

[0055] S4. With the first electric louver valve 81 closed and the second electric valve 82 and the third electric louver valve 83 open, the slag-flushing exhaust steam from the spray device 7 migrates along the exhaust steam bypass pipe outlet section A1 and enters the exhaust steam bypass condenser 14 for secondary condensation. After condensing to the set temperature, it enters the second demister 42 for secondary demisting and then migrates along the exhaust steam bypass pipe return section A2 to be transported back to the mixing and heating zone 9 at the top of the high-altitude granulation tower 1. The condensate flows from top to bottom along the exhaust steam bypass pipe outlet section A1 and collects in the liquid collection tray 6.

[0056] S5. With the first electric louvered valve 8 open and the second electric valve 82 and the third electric louvered valve 83 closed, the slag-flushing exhaust steam from the spray device 7 continues to migrate upward along the tower body of the high-altitude granulation tower 1, enters the third demister 43 for secondary demisting, and then enters the mixing and heating zone 9 after passing through the first electric louvered valve 81.

[0057] S6. The spray water and condensate in the collection tray 6 enter the spray water and condensate treatment unit 13 through pipelines, and after passing through the filter 131, they enter the buffer water tank 132. The conditioning device 133 inputs alkali agent into the buffer water tank 132 through the alkali agent pipeline F to carry out conditioning operation, so that the spray water is weakly alkaline, so as to remove acidic pollutants contained in the slag flushing exhaust steam more efficiently during the spray cooling process. The condensate after conditioning is transported back to the slag flushing water pool 11 through the condensate recovery pipeline E for water replenishment operation. The conditioned spray water is then transported back to the spray device 7 for waste heat recovery operation through the circulating pump 134 and the heat recovery unit 135 for recycling.

[0058] S7. The heat source from the gas heat source unit 15 enters the mixing heating zone 9 through the gas heat source pipeline B, and mixes with the slag flushing exhaust gas after condensation and purification to form an unsaturated heat mixture gas. Under the action of the mixture gas induced draft fan 10, the mixture gas continues to migrate upward along the tower body of the high-altitude granulation tower 1 and is discharged through the outlet of the high-altitude granulation tower 1 without visual pollution.

[0059] S8. The first water tank 17 supplies the cold medium a required for condensing the slag flushing exhaust steam to the heat recovery unit 135 and the exhaust steam bypass condenser 14 through the cold medium transfer pump 16. The heated cold medium a is transported to the water inlet of the blast furnace wall cooling system 18 through the pipeline to realize the recycling of the cold medium.

[0060] S9. The first thermometer and hygrometer 51, the second thermometer and hygrometer 52 and the third thermometer and hygrometer 53 monitor the condensation of the slag flushing exhaust steam to the set temperature in real time; the set temperature is the temperature corresponding to reducing the moisture content of the slag flushing exhaust steam by 50%.

[0061] Example 2

[0062] See Figure 2The governance system in this embodiment is based on Embodiment 1 with the following modifications:

[0063] First, the first demister 41, the first thermometer and hygrometer 51, and the liquid collection tray 6 in Example 1 are removed;

[0064] Second, in this embodiment, the spray water condensate treatment unit 13 is replaced by a conditioning device 133, a circulating pump 134, and a second water replenishment tank 136 instead of the spray water condensate treatment unit 13 of embodiment 1.

[0065] Specifically, the spray water condensate treatment unit 13 includes a conditioning device 133, a circulating pump 134, and a second water supply tank 136. The second water supply tank 136 is connected to the water inlet of the spray device 7 through the circulating pump 134 to provide spray water to the spray device 7. The conditioning device 133 is connected to the top of the second water supply tank 136 through an alkaline agent pipe F.

[0066] The system flow in this embodiment is as follows:

[0067] S1. High-temperature slag from high-temperature slag inlet 3 and flushing water from flushing water inlet 2 are flushed at the bottom of the high-altitude granulation tower 1 to generate high-temperature flushing exhaust steam; the slag-water mixture is transported to the flushing water pool 11 through the slag-water ditch C, and the high-temperature flushing exhaust steam generated in the flushing water pool 11 is returned to the bottom of the high-altitude granulation tower 1 through the exhaust steam return pipe D under the sealing action of the movable sealing cover 12.

[0068] S2. The high-temperature slag flushing exhaust steam generated at the bottom of the high-altitude granulation tower 1 migrates upward along the tower body of the high-altitude granulation tower 1 and enters the spray device 7 for primary condensation operation. The spray water and condensate are collected at the bottom of the high-altitude granulation tower 1 and transported together with the slag water mixture through the slag water ditch C to the slag flushing water pool 11.

[0069] S3. The second makeup water tank 136 is connected to the inlet of the spray device 7 through a pipe and a circulating pump 134 to provide spray water to the spray device 7; the conditioning device 133 is connected to the top of the second makeup water tank 136 through an alkaline agent pipe F to input alkaline agent into the second makeup water tank 136, so that the process water makeup water is weakly alkaline, so as to remove acidic pollutants contained in the slag flushing exhaust steam more efficiently during the spray cooling process;

[0070] S4. With the first electric louvered valve 81 closed and the second electric valve 82 and the third electric louvered valve 83 open, the slag-flushing exhaust steam from the spray device 7 migrates along the exhaust steam bypass pipe outlet section A1 and enters the exhaust steam bypass condenser 14 for secondary condensation. After condensing to the set temperature, it enters the second demister 42 for secondary demisting and then migrates along the exhaust steam bypass pipe return section A2 to be transported back to the mixing and heating zone 9 at the top of the high-altitude granulation tower 1. The condensate flows from top to bottom along the exhaust steam bypass pipe outlet section A1 and collects at the bottom of the high-altitude granulation tower 1.

[0071] S5. With the first electric louvered valve 8 open and the second electric valve 82 and the third electric louvered valve 83 closed, the slag-flushing exhaust steam from the spray device 7 continues to migrate upward along the tower body of the high-altitude granulation tower 1, enters the third demister 43 for secondary demisting, and then enters the mixing and heating zone 9 after passing through the first electric louvered valve 81.

[0072] S6. The heat source from the gas heat source unit 15 enters the mixing heating zone 9 through the gas heat source pipeline B, and mixes with the slag flushing exhaust gas after condensation and purification to form an unsaturated heat mixture gas. Under the action of the mixture gas induced draft fan 10, the mixture gas continues to migrate upward along the tower body of the high-altitude granulation tower 1 and is discharged through the outlet of the high-altitude granulation tower 1 without visual pollution.

[0073] S7. The first water tank 17 is supplied with cold medium a through the cold medium transfer pump 16 to the exhaust steam bypass condenser 14. The heated cold medium a is then transported through a pipeline to the inlet connected to the blast furnace wall cooling system 18 to realize the recycling of the cold medium.

[0074] S8. The second thermometer and hygrometer 52 and the third thermometer and hygrometer 53 monitor the condensation of the slag flushing exhaust steam to the set temperature in real time; the set temperature is the temperature corresponding to a 50% reduction in the moisture content of the slag flushing exhaust steam.

[0075] Example 3

[0076] See Figure 3 The governance system in this embodiment is based on Embodiment 1 with the following modifications:

[0077] First, the spray water and condensate collection device in Example 1 is the liquid collection tray 6, which is replaced by the steam rise liquid collection tray 19 in this example;

[0078] Specifically, the steam collection tray 19 includes a central baffle 191 and a lower tray 192. The outer ring of the lower tray 192 is installed on the inner wall of the high-altitude granulation tower 1. The center of the lower tray 192 has an upwardly extending exhaust pipe. The exhaust pipe has a frustum-shaped cross section that gradually decreases from bottom to top. The exhaust pipe has an exhaust channel for the upward migration of slag flushing steam. The central baffle 191 is located directly above the exhaust channel. The outer ring of the central baffle 191 has a downwardly extending guide edge. The outer diameter of the central baffle 191 is larger than the outer diameter of the exhaust channel outlet end.

[0079] Second, in Example 1, the cold medium a is blast furnace wall cooling water. The inlets of the cold medium a in the waste steam bypass condenser 14 and the heat recovery unit 135 are connected to the cold medium transfer pump 16 and the first makeup water tank 17 in sequence through pipelines, and the outlets are connected to the blast furnace wall cooling system 18 through pipelines to realize the recycling of the cold medium. In this example, the cold medium a is replaced by low temperature air. The inlets of the cold medium a in the waste steam bypass condenser 14 and the heat recovery unit 135 are connected to the blower 20 through pipelines, and the outlets of the cold medium a are connected to the hot blast stove air inlet 21 through pipelines to realize the utilization of waste heat.

[0080] Third, based on the second point, in Example 1, the heat exchange tubes of the heat recovery unit 135 and the waste steam bypass condenser 14 are both made of fluoroplastic material, with a tube diameter of 10-14 mm and a wall thickness of 0.8-1 mm, and the heat exchange tubes are arranged in a U-shape. In this example, the heat recovery unit 135 and the waste steam bypass condenser 14 can be replaced by various types: they can be metal finned tubes with a tube diameter of not less than 38 mm and a wall thickness of 3-5 mm, and the heat exchange tubes are arranged in a tube-to-tube configuration; they can be titanium tubes with a tube diameter of not less than 25 mm and a wall thickness of 1-1.5 mm, and the heat exchange tubes are arranged in a tube-to-tube configuration; or they can be fluoroplastic tubes with a tube diameter of not more than 50 mm and a wall thickness of 1 mm, and the heat exchange tubes are arranged in a tube-to-tube configuration.

[0081] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system, characterized in that: The system includes a high-altitude granulation tower (1), a slag flushing water inlet (2), a high-temperature slag inlet (3), a spraying device (7), a mixed air heating zone (9), and a mixed gas induced draft fan (10) arranged sequentially from bottom to top on the tower body of the high-altitude granulation tower (1); it also includes a slag flushing water tank (11), a spray water condensate treatment unit (13), a waste steam bypass condenser (14), a gas heat source unit (15), and a second demister (42); the spray water condensate treatment unit (13) is connected to the spraying device (7) and provides spray water to the spraying device (7) through a spray water pipe; the slag flushing water tank (11) is connected to the high-altitude granulation tower (1) through a slag water ditch C. The bottom wall of the slag flushing pool (11) is connected to the tower wall of the high-altitude granulation tower (1) through the steam return pipe D; the inlet of the waste steam bypass condenser (14) is connected to the tower wall of the high-altitude granulation tower (1) through the waste steam bypass pipe outlet section A1, and the connection is set above the spray device (7); the outlet of the waste steam bypass condenser (14) is connected to the inlet of the second demister (42); the outlet of the second demister (42) is connected to the inlet of the waste steam bypass pipe return section A2; the outlet of the waste steam bypass pipe return section A2 is connected to the tower wall of the high-altitude granulation tower (1), and the connection is set on one side of the mixed air heating area (9);The gas heat source unit (15) is connected to the tower wall of the high-altitude granulation tower (1) through the gas heat source pipe B. The connection point is located on the other side of the mixed air heating area (9). The mixed gas induced draft fan (10) is located at the outlet of the mixed air heating area (9). The spray water condensate treatment unit (13) includes a filter (131), a buffer water tank (132), a conditioning device (133), a circulating pump (134), and a heat recovery unit (135). A liquid collection device is provided below the spray device (7). The liquid collection device is a liquid collection tray (6) or a steam rise liquid collection tray (20). The inlet of the filter (131) is connected to the outlet of the liquid collection device through the spray water pipe. The outlet of the filter (131) is connected to the outlet of the liquid collection device through the spray water pipe. The inlet of the buffer water tank (132) is connected, the conditioning device (133) is connected to the top of the buffer water tank (132) through the alkaline agent pipe F, the bottom of the buffer water tank (132) is connected to the slag flushing pool (11) through the condensate recovery pipe E, a movable sealing cover (12) is installed above the slag flushing pool (11), the inlet of the circulating pump (134) is connected to the bottom of the buffer water tank (132) through the spray water pipe, the outlet of the circulating pump (134) is connected to the heat medium inlet of the heat recovery unit (135) through the spray water pipe, the heat medium outlet of the heat recovery unit (135) is connected to the spray water inlet of the spray device (7) through the spray water pipe, and the heat recovery unit (135) and the exhaust steam bypass condenser ( The cold medium a in 14) is low-temperature water. The inlets of the cold medium a in the heat recovery unit (135) and the exhaust steam bypass condenser (14) are connected to the cold medium transfer pump (16) and the first makeup water tank (17) in sequence through pipelines. The outlets of the cold medium a are connected to the inlet of the blast furnace wall cooling system (18) through pipelines. A third demister (43) is also provided between the spray device (7) and the mixed air heating area (9). The third demister (43) is located above the connection between the exhaust steam bypass pipeline outlet section A1 and the high-altitude granulation tower (1). A first electric louvered plate valve (81) is provided between the third demister (43) and the mixed air heating area (9). A second electric louver is provided on the exhaust steam bypass pipeline outlet section A1. A third electric louvered louvered louvered valve (83) is installed on the return section A2 of the exhaust steam bypass pipeline. When the first electric louvered louvered valve (81) is closed and the second electric louvered louvered valve (82) and the third electric louvered louvered valve (83) are opened, the spray device (7) and the exhaust steam bypass condenser (14) operate in series. When the first electric louvered louvered valve (81) is opened and the second electric louvered louvered valve (82) and the third electric louvered louvered valve (83) are closed, the spray device (7) operates independently. A first demister (41) is also provided between the high-temperature slag inlet (3) and the spray device (7). The first demister (41) is located above the connection between the steam return pipeline D and the high-altitude granulation tower (1).The first demister (41), the second demister (42), and the third demister (43) each have at least two layers and also include a first thermometer and hygrometer (51), a second thermometer and hygrometer (52), and a third thermometer and hygrometer (53) for real-time monitoring of the slag flushing steam temperature. The first thermometer and hygrometer (51) is located between the first demister (41) and the liquid collection device. The second thermometer and hygrometer (52) is located above the spray device (7). The third thermometer and hygrometer (53) is located at the outlet of the second demister (42). The exhaust steam bypass pipe outlet section A1 and the exhaust steam bypass pipe return section A2 are arranged at an inclination or horizontal angle not exceeding 30°.

2. The high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system as described in claim 1, characterized in that: The spraying device (7) has no less than three spraying layers and is located in the middle of the high-altitude granulation tower (1).

3. The high-temperature water flushing slag exhaust steam energy-saving water collection and pollutant treatment system as described in claim 1, characterized in that: The spray water condensate treatment unit (13) includes a conditioning device (133), a circulating pump (134), and a second water supply tank (136). The second water supply tank (136) is connected to the inlet of the spray device (7) through the circulating pump (134) to provide spray water to the spray device (7). The conditioning device (133) is connected to the top of the second water supply tank (136) through an alkaline agent pipe F.

4. A treatment method for a high-temperature water flushing slag exhaust steam energy-saving water recovery and pollutant treatment system as described in any one of claims 1-3, characterized in that: Includes the following steps: S1. High-temperature slag from the high-temperature slag inlet (3) and flushing water from the flushing water inlet (2) are flushed at the bottom of the high-altitude granulation tower (1) to generate high-temperature flushing exhaust steam; the slag-water mixture is transported to the flushing water pool (11) through the slag-water ditch C, and the high-temperature flushing exhaust steam generated in the flushing water pool (11) is returned to the bottom of the high-altitude granulation tower (1) through the exhaust steam return pipe D under the sealing action of the movable sealing cover (12); S2. The high-temperature slag-flushing exhaust steam generated at the bottom of the high-altitude granulation tower (1) migrates upward along the tower body of the high-altitude granulation tower (1) and enters the first demister (41) for a demisting operation; S3. The high-temperature slag-flushing exhaust steam from the first demister (41) continues to migrate upward along the tower body of the high-altitude granulation tower (1) and enters the spray device (7) for primary condensation operation. The spray water and condensate are collected in the liquid collection tray (6). S4. With the first electric louvered valve (81) closed and the second electric louvered valve (82) and the third electric louvered valve (83) open, the slag-flushing exhaust steam from the spray device (7) migrates along the exhaust steam bypass pipe outlet section A1 and enters the exhaust steam bypass condenser (14) for secondary condensation. After condensing to the set temperature, it enters the second demister (42) for secondary demisting and then migrates along the exhaust steam bypass pipe return section A2 to be transported back to the mixed air heating area (9) at the top of the high-altitude granulation tower (1). The condensate flows from top to bottom along the exhaust steam bypass pipe outlet section A1 and collects in the liquid collection tray (6). S5. With the first electric louvered valve (81) open and the second electric louvered valve (82) and the third electric louvered valve (83) closed, the slag-flushing exhaust steam from the spray device (7) continues to move upward along the tower body of the high-altitude granulation tower (1), enters the third demister (43) for secondary demisting, and then enters the mixed air heating zone (9) after passing through the first electric louvered valve (81). S6. The spray water and condensate in the collection tray (6) enter the spray water and condensate treatment unit (13) through the pipeline, and enter the buffer water tank (132) after passing through the filter (131); the conditioning device (133) inputs the alkali agent into the buffer water tank (132) through the alkali agent pipeline F to carry out the conditioning operation, so that the spray water is weakly alkaline; the condensate after conditioning is transported back to the slag flushing water tank (11) through the condensate recovery pipeline E for water replenishment; the spray water after conditioning is successively passed through the circulation pump (134) and the heat recovery unit (135) for waste heat recovery operation, and then transported back to the spray device (7) for recycling; S7. The heat source from the gas heat source unit (15) enters the mixed air heating area (9) through the gas heat source pipeline B, and mixes with the slag flushing exhaust gas after condensation and purification to form an unsaturated heat mixed gas; the mixed gas continues to migrate upward along the tower body of the high-altitude granulation tower (1) under the action of the mixed gas induced draft fan (10), and is discharged through the outlet of the high-altitude granulation tower (1); S8. The first water tank (17) delivers the cold medium a required for condensing the slag flushing exhaust steam to the heat recovery unit (135) and the exhaust steam bypass condenser (14) through the cold medium transfer pump (16). The heated cold medium a is then transported through a pipeline to the water inlet of the blast furnace wall cooling system (18) to realize the recycling of the cold medium. S9. A first thermometer and hygrometer (51), a second thermometer and hygrometer (52) and a third thermometer and hygrometer (53) monitor in real time the condensation of the slag flushing exhaust steam to a set temperature; the set temperature is the temperature corresponding to a 50% reduction in the moisture content of the slag flushing exhaust steam.

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