CN112853015B - High-efficiency cooling system and method for blast furnace gas - Google Patents

High-efficiency cooling system and method for blast furnace gas Download PDF

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CN112853015B
CN112853015B CN202110014535.4A CN202110014535A CN112853015B CN 112853015 B CN112853015 B CN 112853015B CN 202110014535 A CN202110014535 A CN 202110014535A CN 112853015 B CN112853015 B CN 112853015B
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blast furnace
gas
water
furnace gas
cooling tower
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CN112853015A (en
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徐伟
张天赋
矫继东
赵伟
何嵩
张函
陈鹏
高军
张炎
马光宇
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Angang Steel Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B5/00Making pig-iron in the blast furnace
    • C21B5/06Making pig-iron in the blast furnace using top gas in the blast furnace process
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B7/00Blast furnaces
    • C21B7/10Cooling; Devices therefor
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B7/00Blast furnaces
    • C21B7/22Dust arresters
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B2100/00Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/60Process control or energy utilisation in the manufacture of iron or steel
    • C21B2100/62Energy conversion other than by heat exchange, e.g. by use of exhaust gas in energy production
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B2100/00Handling of exhaust gases produced during the manufacture of iron or steel
    • C21B2100/60Process control or energy utilisation in the manufacture of iron or steel
    • C21B2100/66Heat exchange
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/25Process efficiency

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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Blast Furnaces (AREA)

Abstract

The invention relates to the technical field of high-efficiency application of metallurgical coal gas in the steel industry, in particular to a high-efficiency cooling system and a high-efficiency cooling method for blast furnace coal gas. The system comprises a blast furnace, a furnace top spraying device, a dry dust removal device, a TRT power generation device, a bypass spraying device, a dehumidification device, a bypass pressure reducing valve group, a coal gas cooling tower, a circulating water pool, a CCPP power generation device and a water pump which are connected through pipelines. A blast furnace gas efficient cooling method specifically comprises two operation states, namely a TRT power generation device operation state and a TRT power generation device stop operation state. Aiming at the condition that part of blast furnace raw gas produced by the blast furnace is in a higher temperature range of 250-300 ℃ for a long time, the blast furnace gas is efficiently cooled, the requirement of a CCPP generator set on the blast furnace gas temperature under the matching of an early wet dust removal process is met on the premise of not obviously increasing the circulating water amount, and the restriction bottleneck of changing the wet dust removal method into the dry dust removal method for the blast furnace gas in the steel industry is solved.

Description

High-efficiency cooling system and method for blast furnace gas
Technical Field
The invention relates to the technical field of high-efficiency application of metallurgical coal gas in the steel industry, in particular to a high-efficiency cooling system and a high-efficiency cooling method for blast furnace coal gas.
Background
The blast furnace gas dust removal process of iron and steel enterprises is divided into dry dust removal and wet dust removal, the large blast furnace gas dust removal process put into production in early stage in China basically adopts a wet dust removal mode, the wet dust removal process can lose part of gas excess pressure and excess heat energy, sewage ring water for gas washing is difficult to treat, small particles can circulate and enrich in a sewage ring water treatment system, and finally, the small particles are discharged outside to cause secondary environmental pollution. In recent years, with the improvement of the cloth bag technology, the problem that the cloth bag is easy to damage at the temperature of 180-300 ℃ at the top of the furnace is solved, and the dry dust removal becomes the first choice of the dust removal mode of blast furnace gas in various large steel mills.
Compared with the wet method, the dry method dust removal method has the advantages that not only can the pressure energy of blast furnace gas be fully utilized, but also the sensible heat of the gas is fully utilized, so that the energy which can be recovered by the TRT device is greatly increased. However, the CCPP generator set matched with the original wet dust removal is designed according to the temperature of blast furnace gas after wet dust removal at the beginning of design, and the temperature of the inlet gas is required to be about 35-40 ℃, especially for an early large CCPP generator set, for example, a large CCPP generator set of 300MW with saddle steel, the temperature of the inlet blast furnace gas is required to be not higher than 35 ℃, and the CCPP cannot run at full load to reduce the power generation.
Although the wet method for blast furnace gas dust removal is changed into the dry method, the TRT power generation can be improved, if the problem that the temperature of blast furnace gas is too high cannot be solved, the CCPP power generation is influenced, which is irrecoverable, and is also a main reason for restricting a plurality of iron and steel enterprises from being incapable of carrying out dry method modification on blast furnace gas. Therefore, it is necessary to study the temperature reduction of blast furnace gas under dry dedusting to meet the requirements of the subsequent CCPP operation.
CN107604116A discloses a blast furnace gas processing system and a processing method thereof, in which the temperature of the gas is controlled by a TRT power generation device, although the temperature of the gas can be controlled within a certain range, the temperature of the gas is controlled at the expense of power generation efficiency, which is irrecoverable, and there is a certain controversy. CN105950226A discloses a vertical spray cooling and dewatering integrated system for coal gas, which utilizes water atomized water to spray and cool high-temperature coal gas and wash acidic substances and salt, and then rotates the coal gas containing mechanical water in a vertical coal gas dewatering device to remove mechanical water drops, but the pipeline spray cooling method is difficult to reduce the temperature of the blast furnace coal gas to about 35-40 ℃. CN201525851U discloses "a gas cooling device for a blast furnace gas dry dedusting process", which sprays atomized cooling water into a pipeline through a double-medium atomizing nozzle installed on a blast furnace gas pipeline to cool the blast furnace gas so that the blast furnace gas enters a dry deduster without burning filter materials in the deduster; but the device does not consider the requirements of subsequent gas users on the gas temperature.
In summary, the blast furnace gas cooling system and the method have some problems. The blast furnace gas cooling system and the blast furnace gas cooling method mainly reflect that when part of blast furnace gas produced by a blast furnace is at a high temperature for a long time, the blast furnace gas can not be effectively cooled to about 35 ℃ by the existing blast furnace gas cooling system and method after the original wet dust removal process is changed into the dry dust removal process, so that the temperature requirement of a CCPP (CCPP) generator set matched with the early wet dust removal process can be met. Therefore, it is necessary to find a more practical and effective high-efficiency blast furnace gas cooling system and method.
Disclosure of Invention
Aiming at overcoming the defects of the prior art and aiming at the problem that part of blast furnace gas produced by a blast furnace is in a higher temperature range of 250-300 ℃ for a long time, the invention provides a high-efficiency cooling system and a method for the blast furnace gas. The high-efficiency cooling of the blast furnace gas is realized, the requirement of a CCPP power generation unit on the temperature of the blast furnace gas under the matching condition of an early wet dust removal process is met on the premise of not obviously increasing the circulating water amount, and the restriction bottleneck of changing the wet dust removal method into the dry dust removal method of the blast furnace gas in the steel industry is solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a high-efficiency cooling system for blast furnace gas comprises a furnace top spraying device, a dry dust removal device, a bypass spraying device, a dehumidifying device, a bypass pressure reducing valve bank, a gas cooling tower, a circulating water cooling tower and a circulating water pool;
the devices are connected through pipelines, a gas outlet of the blast furnace is connected with a furnace top spraying device, and the gas outlet of the furnace top spraying device is connected with an inlet of a dry dust removal device;
the coal gas outlet of the dry dust removal device is connected with the TRT power generation device and the inlet of the bypass spraying device, the outlet of the bypass spraying device is connected with the inlet of the dehumidification device, and the outlet of the dehumidification device is connected with the inlet of the bypass pressure reducing valve bank;
the dehumidifying device adopts an efficient membrane separation technology to dehumidify;
the gas outlet of the TRT power generation device and the bypass pressure reducing valve set is connected with the gas inlet of the gas cooling tower, and the gas outlet of the gas cooling tower is connected with the inlet of the CCPP power generation device;
the cooling water outlet of the gas cooling tower is connected with the inlet of the circulating water cooling tower, the outlet of the circulating water cooling tower is connected with the inlet of the circulating water pool, and the outlet of the circulating water pool is connected with the cooling water inlet of the gas cooling tower.
The device also comprises a valve and a water pump.
The water pump is arranged on a connecting pipeline between the outlet of the circulating water pool and the cooling water inlet of the coal gas cooling tower.
A blast furnace gas efficient cooling method specifically comprises two operation states, namely a TRT power generation device operation state and a TRT power generation device stop operation state.
Under the operation state of the TRT power generation device:
1) The temperature of blast furnace gas generated in blast furnace smelting is generally above 220 ℃, and can change along with the fluctuation of the blast furnace condition, even the temperature of blast furnace top raw gas can be in the range of about 250-300 ℃ for a long time; the generated blast furnace gas enters a furnace top spraying device, if the temperature is higher than 180-200 ℃, spraying cooling is carried out, and sprayed fog drops absorb the sensible heat of the blast furnace gas and vaporize into water vapor so as to achieve the purpose of cooling the blast furnace gas; if the temperature is not higher than 180-200 ℃, the spraying cooling is not carried out; the water content of the blast furnace gas at the outlet of the furnace top spraying device after the temperature reduction is 10g/Nm 3 ~40g/Nm 3
2) The furnace top spraying device ensures that the temperature of blast furnace gas is lower than 180-200 ℃ and enters the dry dust removal device to prevent the cloth bag filter material in the dry dust removal device from being burnt out due to overhigh temperature of the gas; the blast furnace gas enters a TRT power generation device after being dedusted by a dry dedusting device, the residual pressure and the waste heat are utilized to generate power, the temperature of the blast furnace gas after being discharged from the TRT power generation device is generally within the range of 60-80 ℃, and the water content is 10g/Nm 3 ~40g/Nm 3 The dew point temperature is lower than 35 ℃.
3) The blast furnace gas flows upwards from the bottom of the gas cooling tower and carries out countercurrent heat exchange with spray water on the upper part of the gas cooling tower, the blast furnace gas is cooled by utilizing sensible heat of the spray water, and the temperature of the gas is reduced to below 35 ℃ by controlling the water amount of the spray water.
4) The temperature of the spray water is raised to 30 ℃ after heat exchange, the spray water enters a circulating water cooling tower from a waterway outlet at the bottom of the gas cooling tower, is cooled to 25 ℃ through the cooling tower and flows into a circulating water pool, and then cooling water in the circulating water pool is circularly pumped into the gas cooling tower by a water pump to cool the blast furnace gas.
In the stop operation state of the TRT power generation device:
1) The temperature of blast furnace gas generated in blast furnace smelting is generally above 220 ℃; the generated blast furnace gas enters a furnace top spraying device, and if the temperature is higher than 180-200 ℃, spraying and cooling are carried out; if the temperature is not higher than 180-200 ℃, the spray cooling is not carried out; the water content of the blast furnace gas at the outlet of the furnace top spraying device after the temperature reduction is 10g/Nm 3 ~40g/Nm 3
2) The furnace top spraying device ensures that the blast furnace gas enters the dry dust removal device when the temperature is lower than 180-200 ℃; the blast furnace gas is dedusted by the dry dedusting device and enters the bypass spraying device for cooling, the sprayed and atomized water drops absorb the heat of the blast furnace gas and are vaporized into water vapor, and the blast furnace gas is cooled to be within the range of 100-120 ℃.
3) The water content of the blast furnace gas after temperature reduction is 50g/Nm 3 ~90g/Nm 3 The pressure is about 230 Kp-240 Kp generally, and the corresponding dew point temperature is 59-72 ℃; if the blast furnace gas in the state directly enters the gas cooling tower to be cooled to 35 ℃ and can be cooled to below the dew point temperature of the blast furnace gas, most of cold energy provided by circulating water of the gas cooling tower is used for cooling water vapor into latent heat of water for cold absorption, and the amount of the circulating water is expected to be increased by 25-90%; in order to ensure that the difference between the circulating water amount of the gas cooling tower in the running state and the fault state of the TRT power generation device is not large, the blast furnace gas enters a dehumidifying device after being cooled by bypass spray, the dehumidifying device adopts a membrane separation technology, and when the blast furnace gas flow is in a state of low temperature, the circulating water amount of the blast furnace gas enters a high-temperature gas cooling towerWhen passing through one side of the high-molecular separation membrane, water vapor enters the other side through the membrane and is discharged under the action of pressure difference between the two sides of the membrane, and dry blast furnace gas is left;
4) The process belongs to a gas membrane separation process, and the process utilizes the self pressure of blast furnace gas to operate without external energy. After passing through the dehumidification device, the water vapor removal efficiency of the blast furnace gas reaches over 90 percent, and the water content of the blast furnace gas is reduced to 5g/Nm 3 ~9g/Nm 3 The pressure of the dehumidified blast furnace gas is reduced to 13 Kp-16 Kp by a bypass pressure reducing valve group, and the dew point temperature of the blast furnace gas is far lower than 35 ℃;
5) The blast furnace gas after dehumidification and pressure reduction flows upwards from the bottom of the gas cooling tower to perform countercurrent heat exchange with spray water on the upper part of the gas cooling tower, the blast furnace gas is cooled by utilizing sensible heat of the spray water, and the temperature of the gas is reduced to below 35 ℃ by controlling the water amount of the spray water.
6) The temperature of the spray water is raised to 30 ℃ after heat exchange, the spray water enters a circulating water cooling tower from a waterway outlet at the bottom of the gas cooling tower, is cooled to 25 ℃ through the cooling tower and flows into a circulating water pool, and then cooling water in the circulating water pool is circularly pumped into the gas cooling tower by a water pump to cool the blast furnace gas.
7) Along with the operation of the dehumidifying device, water vapor can be accumulated on the surface of a downstream side membrane after penetrating through the polymer separation membrane, so that the concentration polarization phenomenon is caused, the membrane separation efficiency is reduced, and the dehumidifying effect is reduced; therefore, accumulated water on the downstream side of the polymer separation membrane needs to be swept and separated in the operation process, the membrane separation water vapor removal efficiency is ensured to be over 90%, and a sweeping gas source can utilize blast furnace gas dehumidified by a dehumidification device; the water separated by purging is discharged through a drainer or can be returned to the circulating water pool as the water supplement.
Compared with the prior art, the invention has the beneficial effects that:
by using the TRT bypass spraying device and the dehumidifying device, the invention ensures that the blast furnace gas produced by the blast furnace is in a higher temperature range of 250-300 ℃ for a long time, and can also control the temperature and the moisture content of the gas entering the gas cooling tower when the TRT power generation device stops operating, and the temperature and the moisture content of the gas entering the gas cooling tower are not greatly different from those of the gas entering the gas cooling tower when the TRT power generation device operates; on the premise of not obviously increasing the circulating water quantity, the circulating water quantity of the gas cooling tower is ensured not to generate large fluctuation, the cooling effect of the gas cooling tower on the temperature of blast furnace gas to be reduced to 35 ℃ is also ensured, and the operation stability and reliability of the whole gas cooling system are improved.
Drawings
FIG. 1 is a schematic diagram of the structure and process of the present invention.
In the figure:
1. a blast furnace, 2, a furnace top spraying device, 3, a dry dedusting device, 4, a TRT power generation device, 5, a bypass spraying device, 6, a dehumidification device, 7, a bypass pressure reducing valve bank, 8, a gas cooling tower, 9, a circulating water cooling tower, 10, a circulating water pool, 11, a CCPP power generation device, 12, a water pump, 13, 14, 15 and 16 switch valves, and 17 switch regulating valves.
Detailed Description
The invention discloses a high-efficiency cooling system and a high-efficiency cooling method for blast furnace gas. Those skilled in the art can modify the process parameters appropriately to achieve the desired results with reference to the disclosure herein. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations and modifications, or appropriate variations and combinations of the methods and applications described herein may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.
A blast furnace gas high-efficiency cooling system comprises a furnace top spraying device 2, a dry dust removal device 3, a bypass spraying device 5, a dehumidification device 6, a bypass pressure reducing valve bank 7, a gas cooling tower 8, a circulating water cooling tower 9, a circulating water pool 10, a water pump 12, switch valves 13, 14, 15 and 16 and a switch regulating valve 17.
Wherein the coal gas outlet of the blast furnace 1 is connected with the furnace top spraying device 2, the coal gas outlet of the furnace top spraying device 2 is connected with the inlet of the dry dust removal device 3, the coal gas outlet of the dry dust removal device 3 is connected with the inlets of the TRT power generation device 4 and the bypass spraying device 5, the outlet of the bypass spraying device 5 is connected with the inlet of the dehumidification device 6, and the outlet of the dehumidification device 6 is connected with the inlet of the bypass pressure reducing valve bank 7.
Meanwhile, the TRT power generation device 4 and the coal gas outlet of the bypass pressure reducing valve group 7 are connected with the coal gas inlet of the coal gas cooling tower 8, and the coal gas outlet of the coal gas cooling tower 8 is connected with the inlet of the CCPP power generation device 11; the cooling water outlet of the coal gas cooling tower 8 is connected with the inlet of a circulating water cooling tower 9, the outlet of the circulating water cooling tower 9 is connected with the inlet of a circulating water pool 10, and the outlet of the circulating water pool 10 is connected with the cooling water inlet of the coal gas cooling tower 8. A water pump 12 is arranged on a pipeline connecting the outlet of the circulating water pool 10 and the cooling water inlet of the coal gas cooling tower 8.
A switch valve 13 is arranged on a pipeline connecting the dry method dust removing device 3 and the bypass spraying device 5, a switch valve 14 is arranged on a pipeline at the outlet of the bypass pressure reducing valve bank 7, a switch valve 15 is arranged on a pipeline connecting the dry method dust removing device 3 and the TRT power generation device 4, a switch valve 16 is arranged on a pipeline at the outlet of the TRT power generation device 4, and a switch regulating valve 17 is arranged on a pipeline connecting the outlet of the dehumidifying device 6 and the inlet of the bypass pressure reducing valve bank 7.
Example 1:
a blast furnace gas high-efficiency cooling method is characterized in that in the running state of a TRT power generation device:
in the TRT power plant operating state, the on-off valves 15, 16 are in the open state, and the on-off valves 13, 14 and the on-off regulating valve 17 are in the closed state.
The temperature of blast furnace gas generated in a blast furnace 1 is 280 ℃, the blast furnace gas enters a furnace top spraying device 2, the furnace top spraying device 2 sprays and atomizes water with the temperature of 25 ℃, sprayed fog drops absorb the sensible heat of the blast furnace gas and are vaporized into water vapor to achieve the purpose of cooling the blast furnace gas, the temperature of the blast furnace gas is reduced to 200 ℃, and the water content of the blast furnace gas at the outlet of the furnace top spraying device 2 is 38.7g/Nm 3 Left and right.
The blast furnace gas after temperature reduction is dedusted by a dry dedusting device 3 and then enters a TRT power generation device 4, the residual pressure and the waste heat are utilized for power generation, the temperature of the blast furnace gas after coming out of the TRT power generation device 4 is 75 ℃, and the water content is 38.7g/Nm 3 The pressure was 16Kp and the dew point temperature was 34 ℃.
Blast furnace gas at 75 ℃ flows upwards from the bottom of the gas cooling tower 8 and carries out countercurrent heat exchange with spray water on the upper part of the gas cooling tower 8, the blast furnace gas is cooled by utilizing sensible heat of the spray water, the outlet temperature of the blast furnace gas is reduced to about 35 ℃ by controlling the water amount of the spray water, and the cooled blast furnace gas is supplied to the CCPP power generation device 11 for power generation.
The temperature of spray water in the gas cooling tower 8 is 25 ℃, the temperature of the spray water is raised to 30 ℃ after heat exchange, the spray water enters a circulating water cooling tower 9 from a water channel at the bottom of the gas cooling tower 8, the spray water is cooled to 25 ℃ through the cooling tower and flows into a circulating water pool 10, and cooling water in the circulating water pool 10 circularly enters the gas cooling tower 8 through a water pump 12 to cool blast furnace gas.
Example 2:
a blast furnace gas high-efficiency cooling method is characterized in that when a TRT power generation device stops operating:
in the TRT power plant shutdown state, the on-off valves 13 and 14 and the on-off regulating valve 17 are in the open state, and the on-off valves 15 and 16 are in the closed state.
The temperature of blast furnace gas generated in a blast furnace 1 is 280 ℃, the blast furnace gas enters a furnace top spraying device 2, the furnace top spraying device 2 sprays and atomizes water with the temperature of 25 ℃, sprayed fog drops absorb the sensible heat of the blast furnace gas and are vaporized into water vapor to achieve the purpose of cooling the blast furnace gas, the temperature of the blast furnace gas is reduced to 200 ℃, and the water content of the blast furnace gas at the outlet of the furnace top spraying device 2 is 38.7g/Nm 3 Left and right.
Then, the blast furnace gas is dedusted by a dry dedusting device 3 and enters a bypass spraying device 5 for secondary cooling, the sprayed and atomized water drops absorb the heat of the blast furnace gas and are vaporized into steam, and the temperature of the blast furnace gas is reduced to 110 ℃; the water content of the blast furnace gas after temperature reduction is 88g/Nm 3 The pressure was about 235Kp, corresponding to a dew point temperature of about 71 ℃.
The coal gas enters a dehumidifying device 6 after temperature reduction, the blast furnace coal gas flows through one side of a high-molecular separation membrane by means of self pressure, water vapor enters the other side through the membrane to be discharged under the action of pressure difference between the two sides of the membrane, the removing efficiency reaches over 90 percent, and the water content of the blast furnace coal gas is reduced to 8.8g/Nm 3 Left and right.
In the dehumidifying device 6, a small amount of dehumidified blast furnace gas is led back to be used as a gas source for sweeping and separating accumulated water on the downstream side of the polymer separation membrane through a switch regulating valve 17, and the separated water is discharged; the pressure of the dehumidified blast furnace gas is reduced to 15Kp by a bypass pressure reducing valve bank 7, and the dew point temperature of the blast furnace gas is far lower than 35 ℃.
Then, the blast furnace gas flows upwards from the bottom of the gas cooling tower 8 and carries out countercurrent heat exchange with spray water on the upper part of the gas cooling tower 8, the blast furnace gas is cooled by utilizing sensible heat of the spray water, the temperature of the blast furnace gas is reduced to be below 35 ℃, and the cooled blast furnace gas is supplied to a CCPP power generation device 11 for power generation.
The temperature of the spray water is 25 ℃, the temperature of the spray water is raised to 30 ℃ after heat exchange, the spray water enters a circulating water cooling tower 9 from a water channel at the bottom of the gas cooling tower 8, the spray water is cooled to 25 ℃ through the cooling tower and flows into a circulating water pool 10, and cooling water in the circulating water pool 10 circularly enters the gas cooling tower 8 through a water pump 12 to circularly cool the blast furnace gas.
According to the invention, through the use of the TRT bypass spraying device and the dehumidifying device, the temperature and the moisture content of the coal gas entering the coal gas cooling tower in the state that the TRT power generation device stops operating are controlled, and the difference between the temperature and the moisture content of the coal gas entering the coal gas cooling tower in the state that the TRT power generation device operates is not large; the circulating water quantity of the gas cooling tower is ensured not to fluctuate greatly, the cooling effect of the gas cooling tower on the temperature of blast furnace gas to be reduced to 35 ℃ is also ensured, and the operation stability and reliability of the whole gas cooling system are improved.
The invention solves the problem that the blast furnace gas temperature is not matched with the requirement of the CCPP power generation device after the blast furnace gas wet dust removal is changed into the dry dust removal, realizes the cooling of the blast furnace gas to 35 ℃, and ensures the requirement of the CCPP power generation device on the blast furnace gas temperature.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (3)

1. The blast furnace gas high-efficiency cooling method is characterized in that the system comprises a furnace top spraying device, a dry dust removal device, a bypass spraying device, a dehumidification device, a bypass pressure reducing valve group, a gas cooling tower, a circulating water cooling tower and a circulating water pool;
the devices are connected through pipelines, a gas outlet of the blast furnace is connected with a furnace top spraying device, and the gas outlet of the furnace top spraying device is connected with an inlet of a dry dust removal device;
the gas outlet of the dry dust removal device is connected with the inlets of the TRT power generation device and the bypass spraying device, the outlet of the bypass spraying device is connected with the inlet of the dehumidification device, and the outlet of the dehumidification device is connected with the inlet of the bypass pressure reducing valve bank;
the TRT power generation device and the gas outlet of the bypass pressure reducing valve set are connected with the gas inlet of the gas cooling tower, and the gas outlet of the gas cooling tower is connected with the inlet of the CCPP power generation device;
a cooling water outlet of the gas cooling tower is connected with an inlet of a circulating water cooling tower, an outlet of the circulating water cooling tower is connected with an inlet of a circulating water pool, and an outlet of the circulating water pool is connected with a cooling water inlet of the gas cooling tower;
the gas cooling tower is characterized by also comprising a valve and a water pump, wherein the water pump is arranged on a connecting pipeline between the outlet of the circulating water pool and the cooling water inlet of the gas cooling tower;
the method comprises the following steps of (1) enabling a TRT power generation device to be in an operation state and enabling the TRT power generation device to be in a stop operation state;
in a TRT power plant operating state:
1) Blast furnace gas generated in blast furnace smelting and with the temperature of 280-300 ℃ is sent into a furnace top spraying device for spraying and cooling, and the water content of the blast furnace gas after cooling is controlled to be 38.7g/Nm 3 ~40g/Nm 3
2) The blast furnace gas with the temperature lower than 200 ℃ after being cooled by spraying enters a dry dust removal device, the blast furnace gas after being dedusted by the dry dust removal device enters a TRT power generation device, the residual pressure and the waste heat are utilized to generate power, the temperature of the blast furnace gas after coming out of the TRT power generation device is in the range of 60-80 ℃, and the water content is 38.7g/Nm 3 ~40g/Nm 3 Dew point temperatureBelow 35 ℃;
3) The blast furnace gas flows upwards from the bottom of the gas cooling tower and carries out countercurrent heat exchange with spray water on the upper part of the gas cooling tower, the blast furnace gas is cooled by utilizing the sensible heat of the spray water, and the temperature of the gas is reduced to below 35 ℃ by controlling the water amount of the spray water;
in the stop operation state of the TRT power generation device:
1) Blast furnace gas generated in blast furnace smelting and with the temperature of 280-300 ℃ is sent into a furnace top spraying device for spraying and cooling, and the water content of the blast furnace gas after cooling is controlled to be 38.7g/Nm 3 ~40g/Nm 3
2) The blast furnace gas with the temperature lower than 200 ℃ after being cooled by spraying enters a dry dust removal device, the blast furnace gas after being removed dust by the dry dust removal device enters a bypass, then the blast furnace gas enters a bypass spraying device for cooling, the sprayed and atomized water drops absorb the heat of the blast furnace gas and are vaporized into steam, and the blast furnace gas is cooled to the range of 100-120 ℃;
3) The water content of the blast furnace gas after temperature reduction is 50g/Nm 3 ~90g/Nm 3 The pressure is 230 kPa-240 kPa, and the corresponding dew point temperature is 59-72 ℃; the blast furnace gas after the bypass spray cooling enters a dehumidifying device, the dehumidifying device adopts a membrane separation technology, when the blast furnace gas flows through one side of a high-molecular separation membrane, water vapor enters the other side through the membrane to be discharged under the action of pressure difference between the two sides of the membrane, and dry blast furnace gas is left;
4) After passing through the dehumidification device, the water vapor removal efficiency of the blast furnace gas reaches over 90 percent, and the water content of the blast furnace gas is reduced to 5g/Nm 3 ~9g/Nm 3 The pressure of the dehumidified blast furnace gas is reduced to 13-16 kPa through a bypass pressure reducing valve bank, and the dew point temperature of the blast furnace gas is lower than 35 ℃;
5) The blast furnace gas after dehumidification and pressure reduction flows upwards from the bottom of the gas cooling tower to perform countercurrent heat exchange with spray water on the upper part of the gas cooling tower, the blast furnace gas is cooled by utilizing sensible heat of the spray water, and the temperature of the gas is reduced to below 35 ℃ by controlling the water amount of the spray water;
6) In the operation process, the blast furnace gas dehumidified by the dehumidifying device is used as a purging gas source to purge and separate accumulated water on the downstream side of the polymer separation membrane, and the purged and separated water is discharged through a drainer or flows back to a circulating water pool to be used as water supplement.
2. The high-efficiency blast furnace gas cooling method according to claim 1, wherein in the operating state of the TRT power generation plant: after heat exchange, the water temperature rises to 30 ℃, the water enters a circulating water cooling tower from a water channel outlet at the bottom of the coal gas cooling tower, the water is cooled to 25 ℃ by the cooling tower and flows into a circulating water tank, and then cooling water in the circulating water tank is circularly pumped into the coal gas cooling tower by a water pump to cool the blast furnace gas.
3. The method for efficiently cooling blast furnace gas according to claim 1, wherein in a state where the TRT power plant is not operating: the temperature of spray water is raised to 30 ℃ after heat exchange, the spray water enters a circulating water cooling tower from a waterway outlet at the bottom of the gas cooling tower, is cooled to 25 ℃ through the cooling tower and flows into a circulating water pool, and then cooling water in the circulating water pool is circularly pumped into the gas cooling tower by a water pump to cool blast furnace gas.
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JP3956834B2 (en) * 2002-10-29 2007-08-08 Jfeスチール株式会社 Blast furnace gas dust collection method
CN101074453A (en) * 2006-09-13 2007-11-21 童裳慧 Efficient economical dust collecting method and dust collector for iron-smelting blast furnace
CN101603107B (en) * 2009-07-14 2011-04-20 河北省首钢迁安钢铁有限责任公司 System for removing corrosive substances in coal gas obtained by dry dedusting of blast furnace and process thereof
CN202465752U (en) * 2012-02-29 2012-10-03 中冶赛迪工程技术股份有限公司 Dry process dust removing device of blast furnace gas
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CN107385130A (en) * 2017-07-17 2017-11-24 常州大学 A kind of blast furnace gas purification technique
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