CN106219650B - Low-quality waste heat utilization system of steel plant and use method thereof - Google Patents
Low-quality waste heat utilization system of steel plant and use method thereof Download PDFInfo
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- CN106219650B CN106219650B CN201610743683.9A CN201610743683A CN106219650B CN 106219650 B CN106219650 B CN 106219650B CN 201610743683 A CN201610743683 A CN 201610743683A CN 106219650 B CN106219650 B CN 106219650B
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/16—Treatment of water, waste water, or sewage by heating by distillation or evaporation using waste heat from other processes
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/08—Seawater, e.g. for desalination
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- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
Abstract
The invention provides a low-quality waste heat utilization system of a steel plant and a use method thereof, wherein the system comprises: the primary heat exchange device is used for transferring heat between a first fluid and a second fluid, the first fluid is desalted water, and the second fluid is blast furnace slag flushing water; the secondary heat exchange device is used for transferring heat between a third fluid and a fourth fluid, the third fluid is desalted water flowing out of the primary heat exchange device, and the fourth fluid is high-temperature flue gas; and the flash evaporation device is communicated with the secondary heat exchange device, and desalted water discharged from the secondary heat exchange device enters the flash evaporation device to be converted into steam which is used as a heat source of the seawater desalination device to be evaporated to obtain seawater distilled water. The invention adopts low-quality heat sources such as blast furnace slag flushing water and flue gas waste heat of a steel plant to replace the heat source of low-temperature multi-effect seawater desalination, effectively utilizes the waste heat, and reduces the production cost of the low-temperature multi-effect seawater desalination.
Description
Technical Field
The invention belongs to the technical field of waste heat recovery, and particularly relates to a low-quality waste heat utilization system of an iron and steel plant and a use method thereof.
Background
At present, the recovery rate of waste heat and complementary energy in the iron and steel industry is low, low-temperature waste heat accounts for about 35% of the total waste heat, the recovery rate is almost zero, most of the low-temperature waste heat is wasted and is not recycled, and therefore the low-temperature waste heat in the iron and steel industry has huge recovery potential. In the process of an iron-making process of a blast furnace, slag flushing water absorbs heat of iron slag and is discharged into the atmosphere through a cooling water tower, energy waste is caused, the recovery of the waste heat of the slag flushing water in the prior steel plant is mainly embodied in heating in winter, but the water quantity of the slag flushing water is large, the contained heat is large, the heating load of common plant office buildings is small, the waste heat capacity of the slag flushing water cannot be fully exerted, the heating is only suitable for being used in winter in cities in the north, summer is not needed, and the heating is not needed all the year round in cities in the south, so the mode has limitation. Besides the waste heat of blast furnace slag flushing water, a large amount of flue gas waste heat is not well utilized in iron and steel enterprises, for example, flue gas of a hot blast stove and flue gas of a gas boiler, and the flue gas is not easy to collect and has no suitable use object, so that only a large amount of heat energy can be carried to exhaust the atmosphere, and the part of waste heat is not utilized basically.
Disclosure of Invention
Aiming at the problem of low utilization rate of low-quality waste heat of the iron and steel plant in the prior art, the invention provides the low-quality waste heat utilization system of the iron and steel plant and the use method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme: a low-quality waste heat utilization system of a steel plant comprises:
a primary heat exchange device for transferring heat between a first fluid and a second fluid, the primary heat exchange device comprising: a first channel fluid passageway for a first fluid, the first channel fluid passageway provided with a first inlet and a first outlet; the first inlet, the first outlet, the second inlet and the second outlet are separately arranged at the end part of the primary heat exchange device, the first fluid is desalted water, and the second fluid is blast furnace slag flushing water;
a secondary heat exchange device for transferring heat between a third fluid and a fourth fluid, the secondary heat exchange device comprising: a third channel fluid passageway for a third fluid, the third channel fluid passageway provided with a third inlet and a third outlet; and a fourth channel fluid passage for a fourth fluid, the fourth channel fluid passage is provided with a fourth inlet and a fourth outlet, the third and fourth channel fluid passages are adjacently arranged, the third inlet, the third outlet, the fourth inlet and the fourth outlet are separately arranged at the end part of the secondary heat exchange device, the third fluid is desalted water flowing out from the first outlet, and the fourth fluid is high-temperature flue gas; the first outlet of the primary heat exchange device is communicated with the third inlet of the secondary heat exchange device;
and the flash evaporation device is communicated with a third outlet of the secondary heat exchange device, and the desalted water from the third outlet enters the flash evaporation device to be converted into steam which is used as a heat source of the seawater desalination device to be evaporated to obtain seawater distilled water.
Preferably, the temperature of the blast furnace slag flushing water is 75-95 ℃, and the temperature of the high-temperature flue gas is 150-200 ℃.
As a further preference, the system further includes a temperature stabilizing device, located between the secondary heat exchange device and the flash evaporation device, for stabilizing the temperature of the fifth fluid, and the temperature stabilizing device includes: a fifth channel fluid passageway for a fifth fluid, the fifth channel fluid passageway provided with a fifth inlet and a fifth outlet; and a sixth channel fluid passage for a sixth fluid, wherein the sixth channel fluid passage is provided with a sixth inlet and a sixth outlet, the fifth and sixth channel fluid passages are adjacently arranged, the fifth inlet, the fifth outlet, the sixth inlet and the sixth outlet are separately arranged at the end part of the temperature stabilizing device, the fifth fluid is desalted water coming out of the third outlet, the sixth fluid is pipe network low-pressure steam and sintering waste heat boiler low-pressure steam, and the third outlet of the secondary heat exchange device is communicated with the fifth inlet of the temperature stabilizing device.
As a further preference, the system further comprises a steam ejector connected with the steam outlet of the flash device and used for converting the flashed steam into saturated steam with further reduced pressure.
Preferably, the seawater desalination device is provided with a desalted water outlet pipeline, steam and desalted water in the flash evaporation device enter the seawater desalination device to exchange heat, steam condensate water and desalted water after heat transfer are discharged from the desalted water outlet pipeline, and the desalted water outlet pipeline is communicated with the first inlet of the primary heat exchange device.
Preferably, the seawater desalination device is a low-temperature multi-effect distillation seawater desalination device.
A use method of a low-quality waste heat utilization system of a steel plant comprises the following steps:
transferring the heat of the blast furnace slag flushing water to demineralized water;
transferring the heat of the flue gas to demineralized water for obtaining the heat of blast furnace slag washing water;
the desalted water with the heat of the flue gas is flashed to obtain steam which is used as a heat source for evaporating the steam in the seawater desalination device to obtain seawater distilled water.
As a further preference, the method further comprises: and the desalted water after flash evaporation is used for heating raw material seawater, and the raw material seawater is used as spraying water for seawater desalination after being heated.
As a further preference, the method further comprises: and exchanging heat with blast furnace slag flushing water and high-temperature flue gas again by the desalted water after the raw material seawater is heated, and evaporating to obtain seawater distilled water by using the steam obtained by flash evaporation as a heat source of a seawater desalting device.
As a further preference, the method further comprises: and after the desalted water vapor is used as a heat source for seawater desalination, the obtained steam condensate water exchanges heat with blast furnace slag flushing water and high-temperature flue gas again, and after the steam is obtained by flash evaporation, the steam is used as a heat source of a seawater desalination device to be evaporated to obtain seawater distilled water.
As a further preference, the method further comprises: the desalted water after the raw material seawater is heated is mixed with condensed water obtained by cooling desalted water vapor, the mixed condensed water exchanges heat with blast furnace slag flushing water and high-temperature flue gas again, and the mixed condensed water is used as a heat source of a seawater desalination device to be evaporated to obtain seawater distilled water after the vapor is obtained by flash evaporation.
The invention has the following beneficial effects: with the increasingly scarce water resources, the development of seawater desalination is more and more emphasized, and in coastal iron and steel enterprises, the seawater desalination is an effective way for solving the problem of water consumption of enterprises, particularly low-temperature multi-effect distillation seawater desalination is more and more favored by the coastal iron and steel enterprises due to the advantages of low operating temperature and the like, but the biggest problem of seawater desalination is higher water production cost at present. At present, the most common low-temperature multi-effect distillation seawater desalination steam heat source applied in China is generally lower than 70 ℃, the temperature of blast furnace slag flushing water is between 75 and 95 ℃, and the temperature of flue gas waste heat is between 150 and 200 ℃. In the prior art, the research of utilizing low-quality heat sources such as blast furnace slag flushing water and flue gas waste heat of a steel plant to replace a low-temperature multi-effect heat source for seawater desalination so as to reduce the production cost of seawater desalination is not found.
(1) The invention fully utilizes different temperature grades of low-quality waste heat of iron and steel enterprises to heat the desalted water in a cascade manner, the desalted water is taken as a heat exchange medium, the heat exchange is firstly carried out with blast furnace slag flushing water with lower temperature, then the heat exchange is carried out with flue gas with higher temperature, and the desalted water after two-stage heating reaches the temperature required by a heat source of a seawater desalination device. The invention recovers blast furnace slag washing water and waste heat of flue gas of a hot blast stove and a gas boiler for seawater desalination according to the strategic principle of energy conservation and emission reduction sustainable development, greatly reduces the cost of hot seawater desalination steam, further reduces waste of waste heat and complementary energy of a steel plant and reduces the overall energy consumption and pollutant emission of the steel plant while manufacturing desalinated water by using a seawater desalination device to save fresh water on the earth surface, so that the technology meets the encouragement supporting requirements of related national industrial policies, and has economic benefit and social benefit.
(2) The invention produces low-pressure (32-35kpa) saturated steam by flash evaporation of the desalted water after two-stage heating, the saturated steam is used as a heat source of a seawater desalination device to produce desalted water, the desalted water after flash evaporation is used for heating raw material seawater and is used as spray seawater, and the desalted water with reduced temperature and condensed water obtained by cooling the desalted water steam are returned to a first-stage heat exchange device to exchange heat again to complete circulation, thereby realizing closed circulation of the desalted water.
(3) The steam after flash evaporation is pumped and pressurized by taking low-pressure steam (0.6Mpa) as a power source to generate low-pressure (32-35kpa) saturated steam, so that the stability of a low-temperature multi-effect distilled seawater desalination steam source is ensured.
(4) In the invention, the fluctuation of the residual heat of the slag flushing water, the hot blast stove, the flue gas of a gas boiler and the like is considered, the temperature stabilizing device for the desalted water is arranged in front of the flash evaporation device, and the low-pressure steam of a pipe network and the low-pressure steam generated by a sintering waste heat boiler and the like are used as stable supplementary heat sources, so that the stability of the temperature of the desalted water is ensured.
Drawings
Fig. 1 is a schematic process flow diagram of a low-quality waste heat utilization system of an iron and steel plant according to an embodiment of the invention.
Fig. 2 is a schematic process flow diagram of a low-quality waste heat utilization system of an iron and steel plant in embodiment 1 of the invention.
Fig. 3 is a schematic process flow diagram of a low-quality waste heat utilization system of an iron and steel plant in embodiment 2 of the invention.
Detailed Description
The invention provides a low-quality waste heat utilization system and method for an iron and steel plant, which adopt low-quality heat sources such as blast furnace slag flushing water, flue gas waste heat and the like of the iron and steel plant to replace heat sources for low-temperature multi-effect seawater desalination, effectively utilize waste heat and reduce the production cost of low-temperature multi-effect seawater desalination.
The embodiment of the invention provides a low-quality waste heat utilization system for an iron and steel plant, which comprises:
a primary heat exchange device for transferring heat between a first fluid and a second fluid, the primary heat exchange device comprising: a first channel fluid passageway for a first fluid, the first channel fluid passageway providing a first inlet and a first outlet; the first inlet, the first outlet, the second inlet and the second outlet are separately arranged at the end part of the primary heat exchange device, the first fluid is desalted water, and the second fluid is blast furnace slag flushing water;
a secondary heat exchange device for transferring heat between a third fluid and a fourth fluid, the secondary heat exchange device comprising: a third channel fluid passageway for a third fluid, the third channel fluid passageway provided with a third inlet and a third outlet; and a fourth channel fluid passage for a fourth fluid, the fourth channel fluid passage is provided with a fourth inlet and a fourth outlet, the third and fourth channel fluid passages are adjacently arranged, the third inlet, the third outlet, the fourth inlet and the fourth outlet are separately arranged at the end part of the secondary heat exchange device, the third fluid is desalted water flowing out from the first outlet, and the fourth fluid is high-temperature flue gas; the first outlet of the primary heat exchange device is communicated with the third inlet of the secondary heat exchange device;
and the flash evaporation device is communicated with a third outlet of the secondary heat exchange device, and the desalted water from the third outlet enters the flash evaporation device to be converted into steam which is used as a heat source of the seawater desalination device to be evaporated to obtain seawater distilled water.
As shown in fig. 1, the application method of the low-quality waste heat utilization system in the steel plant in the embodiment of the invention comprises the following steps:
transferring the heat of the blast furnace slag flushing water to demineralized water;
transferring the heat of the flue gas to demineralized water for obtaining the heat of blast furnace slag washing water;
the desalted water with the heat of the flue gas is flashed to obtain steam which is used as a heat source for evaporating the steam in the seawater desalination device to obtain seawater distilled water.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
Example 1
As shown in fig. 2, the low-quality waste heat utilization system of the iron and steel plant in embodiment 1 of the present invention includes:
a primary water-water heat exchanger for transferring heat between a first fluid and a second fluid, the primary water-water heat exchanger comprising: a first channel fluid passageway for a first fluid, the first channel fluid passageway provided with a first inlet and a first outlet; the first inlet, the first outlet, the second inlet and the second outlet are separately arranged at the end part of the primary water-water heat exchanger, the first fluid is desalted water, and the second fluid is blast furnace slag flushing water;
a secondary gas-water heat exchanger in communication with the primary water-water heat exchanger for transferring heat between a third fluid and a fourth fluid, the secondary gas-water heat exchanger comprising: a third channel fluid passageway for a third fluid, the third channel fluid passageway provided with a third inlet and a third outlet; and a fourth channel fluid passage for a fourth fluid, the fourth channel fluid passage being provided with a fourth inlet and a fourth outlet, the third and fourth channel fluid passages being arranged adjacently, the third inlet, the third outlet, the fourth inlet and the fourth outlet being separately provided at the end of the secondary gas-water heat exchanger, the third fluid being desalted water flowing out from the first outlet, and the fourth fluid being high temperature flue gas; the first outlet of the primary water-water heat exchanger is communicated with the third inlet of the secondary gas-water heat exchanger;
and the flash tank is communicated with a third outlet of the secondary gas-water heat exchanger, and desalted water from the third outlet enters the flash tank to be converted into steam which is used as a heat source for evaporating in the seawater desalination device to obtain seawater distilled water.
And the steam ejector is connected with the steam outlet of the flash tank and is used for converting the steam after flash evaporation into saturated steam with further reduced pressure.
The temperature of slag flushing water return water generated by blast furnace water slag flushing is generally 75-95 ℃, the partial heat is transferred to demineralized water through heat exchange of a primary water-water heat exchanger, the temperature of the slag flushing water supply water after heat exchange is reduced to about 65 ℃ to meet the requirement of slag flushing temperature, the temperature of the demineralized water is increased from 60 ℃ to about 75 ℃, then the demineralized water is subjected to heat exchange with flue gas waste heat through a secondary gas-water heat exchanger, flue gas is discharged after heat exchange, and the temperature of the demineralized water is further increased to about 85 ℃. After twice heat exchange, the temperature of the desalted water reaches the flash evaporation requirement, the desalted water is conveyed to a seawater desalination area through a pipeline, the desalted water enters a flash tank in the area, steam is flashed out of the flash tank due to pressure reduction of the desalted water, low-pressure steam of 32kpa and 68 ℃ is generated through the ejection effect of a power steam ejector, the part of the steam is used as a heat source of a seawater desalination device, the seawater is evaporated through condensation heat of the steam, and the steam is used for producing desalinated water for users of steel plants.
Example 2
As shown in fig. 3, the low-quality waste heat utilization system of the iron and steel plant in embodiment 2 of the present invention includes:
a primary water-water heat exchanger for transferring heat between a first fluid and a second fluid, the primary water-water heat exchanger comprising: a first channel fluid passageway for a first fluid, the first channel fluid passageway provided with a first inlet and a first outlet; the first inlet, the first outlet, the second inlet and the second outlet are separately arranged at the end part of the primary water-water heat exchanger, the first fluid is desalted water, and the second fluid is blast furnace slag flushing water;
a secondary gas-water heat exchanger in communication with the primary water-water heat exchanger for transferring heat between a third fluid and a fourth fluid, the secondary gas-water heat exchanger comprising: a third channel fluid passageway for a third fluid, the third channel fluid passageway provided with a third inlet and a third outlet; and a fourth channel fluid passage for a fourth fluid, the fourth channel fluid passage being provided with a fourth inlet and a fourth outlet, the third and fourth channel fluid passages being arranged adjacently, the third inlet, the third outlet, the fourth inlet and the fourth outlet being separately provided at the end of the secondary gas-water heat exchanger, the third fluid being desalted water flowing out from the first outlet, and the fourth fluid being high temperature flue gas; the first outlet of the primary water-water heat exchanger is communicated with the third inlet of the secondary gas-water heat exchanger;
and the flash tank is communicated with a third outlet of the secondary gas-water heat exchanger, and desalted water from the third fluid outlet enters the flash tank to be converted into steam which is used as a heat source for evaporating in the seawater desalination device to obtain seawater distilled water.
And the steam ejector is connected with the steam outlet of the flash tank and is used for converting the steam after flash evaporation into saturated steam with further reduced pressure.
The temperature stabilizing device is located between second grade heat transfer device and the flash distillation plant for stabilize the temperature of fifth fluid, the temperature stabilizing device includes: a fifth channel fluid passageway for a fifth fluid, the fifth channel fluid passageway provided with a fifth inlet and a fifth outlet; and a sixth channel fluid passage for a sixth fluid, wherein the sixth channel fluid passage is provided with a sixth inlet and a sixth outlet, the fifth and sixth channel fluid passages are adjacently arranged, the fifth inlet, the fifth outlet, the sixth inlet and the sixth outlet are separately arranged at the end part of the temperature stabilizing device, the fifth fluid is desalted water coming out of the third outlet, the sixth fluid is pipe network low-pressure steam and sintering waste heat boiler low-pressure steam, and the third outlet of the secondary heat exchange device is communicated with the fifth inlet of the temperature stabilizing device.
And exchanging the seawater desalting plate, wherein the desalted water passing through the flash tank is used for heating the raw material seawater, and the spraying seawater is obtained through exchanging the seawater desalting plate.
And the steam and the desalted water passing through the flash tank enter the seawater desalination device to exchange heat, the steam condensate water and the desalted water with reduced temperature are discharged from a desalted water outlet pipeline of the seawater desalination device, and the desalted water outlet pipeline of the seawater desalination device is communicated with the primary heat exchange device to form closed cycle.
In embodiment 2 of the invention, the seawater desalination adopts a low-temperature multi-effect distillation process, the multi-effect distillation is to lead heating steam to be introduced into a first effect of the device, the condensation heat of the heating steam enables almost equal amount of seawater to be evaporated, the evaporation temperature of the subsequent evaporation is lower than that of the previous effect through multiple evaporation and condensation, so that distilled water with the amount of times of the steam is obtained, and the steam of the last effect is condensed in a seawater condenser. The first effect condensate is returned to the boiler, and the condensate of the other effect and seawater condensers is collected and used as product water.
The temperature of slag flushing water return water generated by blast furnace water slag flushing is generally 75-95 ℃, the partial heat is transferred to demineralized water through heat exchange of a primary water-water heat exchanger, the temperature of the slag flushing water supply water after heat exchange is reduced to about 65 ℃ to meet the requirement of slag flushing temperature, the temperature of the demineralized water is increased from 60 ℃ to about 75 ℃, then the demineralized water is subjected to heat exchange with flue gas waste heat through a secondary gas-water heat exchanger, flue gas is discharged after heat exchange, and the temperature of the demineralized water is further increased to about 85 ℃. After the desalted water is subjected to two times of heat exchange, the temperature of the desalted water is ensured by low-pressure steam of a pipe network and low-pressure steam of a sintering waste heat boiler added in a temperature stabilizing device, the temperature of the desalted water meets the requirement of flash evaporation, the desalted water is conveyed to a seawater desalination area through a pipeline, the desalted water enters a flash tank in the area, the steam is flashed out of the flash tank due to pressure reduction, low-pressure steam of 35kpa and 70 ℃ is generated through the injection action of a power steam injector, the part of steam is used as a heat source of a seawater desalination device and enters the device for the first effect, secondary steam produced by heat exchange with sprayed seawater is used for producing desalted water for users of steel plants, meanwhile, the part of low-pressure steam is cooled into steam condensate water by the sprayed seawater, the temperature of the desalted water after flash evaporation is about 68 ℃, the temperature of the desalted water used for heating, the temperature of the desalted water after the temperature is reduced is about 60 ℃ after the desalted water and the steam condensate water are mixed, so that the desalted water is converted into a seawater desalination heat source after absorbing the waste heat of the slag flushing water and the waste heat of the flue gas through a series of heat exchange under the condition that the water quantity is almost not lost, and then the seawater desalination heat source returns to the beginning of the flow, thereby completing one closed cycle.
The technical scheme in the embodiment of the application at least has the following technical effects or advantages:
(1) the invention fully utilizes different temperature grades of low-quality waste heat of iron and steel enterprises to heat the desalted water in a cascade manner, the desalted water is taken as a heat exchange medium, the heat exchange is firstly carried out with blast furnace slag flushing water with lower temperature, then the heat exchange is carried out with flue gas with higher temperature, and the desalted water after two-stage heating reaches the temperature required by a heat source of a seawater desalination device. The invention recovers blast furnace slag washing water and waste heat of flue gas of a hot blast stove and a gas boiler for seawater desalination according to the strategic principle of energy conservation and emission reduction sustainable development, greatly reduces the cost of hot seawater desalination steam, further reduces waste of waste heat and complementary energy of a steel plant and reduces the overall energy consumption and pollutant emission of the steel plant while manufacturing desalinated water by using a seawater desalination device to save fresh water on the earth surface, so that the technology meets the encouragement supporting requirements of related national industrial policies, and has economic benefit and social benefit.
(2) The invention produces low-pressure (32-35kpa) saturated steam by flash evaporation of the desalted water after two-stage heating, the saturated steam is used as a heat source of a seawater desalination device to produce desalted water, the desalted water after flash evaporation is used for heating raw material seawater and is used as spray seawater, and the desalted water with reduced temperature and condensed water obtained by cooling the desalted water steam are returned to a first-stage heat exchange device to exchange heat again to complete circulation, thereby realizing closed circulation of the desalted water.
(3) The steam after flash evaporation is pumped and pressurized by taking low-pressure steam (0.6Mpa) as a power source to generate low-pressure (32-35kpa) saturated steam, so that the stability of a low-temperature multi-effect distilled seawater desalination steam source is ensured.
(4) In the invention, the fluctuation of the residual heat of the slag flushing water, the hot blast stove, the flue gas of a gas boiler and the like is considered, the temperature stabilizing device for the desalted water is arranged in front of the flash evaporation device, and the low-pressure steam of a pipe network and the low-pressure steam generated by a sintering waste heat boiler and the like are used as stable supplementary heat sources, so that the temperature of the desalted water is ensured.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (8)
1. The utility model provides a low-quality waste heat utilization system of iron and steel plant which characterized in that: the method comprises the following steps:
a primary heat exchange device for transferring heat between a first fluid and a second fluid, the primary heat exchange device comprising: a first channel fluid passageway for a first fluid, the first channel fluid passageway provided with a first inlet and a first outlet; the first inlet, the first outlet, the second inlet and the second outlet are separately arranged at the end part of the primary heat exchange device, the first fluid is desalted water, and the second fluid is blast furnace slag flushing water;
a secondary heat exchange device for transferring heat between a third fluid and a fourth fluid, the secondary heat exchange device comprising: a third channel fluid passageway for a third fluid, the third channel fluid passageway provided with a third inlet and a third outlet; the third inlet, the third outlet, the fourth inlet and the fourth outlet are separately arranged at the end part of the secondary heat exchange device, the third fluid is desalted water flowing out of the first outlet, and the fourth fluid is high-temperature flue gas; the first outlet of the primary heat exchange device is communicated with the third inlet of the secondary heat exchange device;
the flash evaporation device is communicated with a third outlet of the secondary heat exchange device, and desalted water from the third outlet enters the flash evaporation device to be converted into steam which is used as a heat source of the seawater desalination device to be evaporated to obtain seawater distilled water;
the temperature stabilizing device is located between second grade heat transfer device and the flash distillation plant for stabilize the temperature of fifth fluid, the temperature stabilizing device includes: a fifth channel fluid passageway for a fifth fluid, the fifth channel fluid passageway provided with a fifth inlet and a fifth outlet; the fifth inlet, the fifth outlet, the sixth inlet and the sixth outlet are separately arranged at the end parts of the temperature stabilizing device, the fifth fluid is desalted water coming out of the third outlet, the sixth fluid is pipe network low-pressure steam and sintering waste heat boiler low-pressure steam, the third outlet of the secondary heat exchange device is communicated with the fifth inlet of the temperature stabilizing device, and the fifth outlet of the temperature stabilizing device is communicated with the flash evaporation device;
and the steam ejector is connected with a steam outlet of the flash evaporation device and is used for converting the steam after flash evaporation into saturated steam with further reduced pressure.
2. The low-quality waste heat utilization system of the steel plant according to claim 1, characterized in that: the temperature of the blast furnace slag flushing water is 75-95 ℃, and the temperature of the high-temperature flue gas is 150-200 ℃.
3. The low-quality waste heat utilization system of the steel plant according to claim 1, characterized in that: the seawater desalination device is provided with a desalted water outlet pipeline, steam condensate water and desalted water after heat transfer are discharged from the desalted water outlet pipeline, and the desalted water outlet pipeline is communicated with a first inlet of the primary heat exchange device.
4. The low-quality waste heat utilization system of the steel plant according to claim 1, characterized in that: the seawater desalination device is a low-temperature multi-effect distillation seawater desalination device.
5. Use method of a low quality waste heat utilization system of a steel plant according to any of claims 1-4, characterized in that: the method comprises the following steps:
transferring the heat of the blast furnace slag flushing water to demineralized water;
transferring the heat of the high-temperature flue gas to demineralized water for obtaining the heat of blast furnace slag flushing water;
and (3) carrying out flash evaporation on the desalted water with the high-temperature flue gas heat to obtain steam, and using the steam as a heat source of the seawater desalination device to evaporate to obtain seawater distilled water.
6. The use method of the low-quality waste heat utilization system of the steel plant according to claim 5, characterized in that: the method further comprises the following steps: and the desalted water after flash evaporation is used for heating raw material seawater, and the raw material seawater is used as spraying water for seawater desalination after being heated.
7. The use method of the low-quality waste heat utilization system of the steel plant according to claim 6, characterized in that: the method further comprises the following steps: and exchanging heat with blast furnace slag flushing water and high-temperature flue gas again by the desalted water after the raw material seawater is heated, and evaporating to obtain seawater distilled water by using the steam obtained by flash evaporation as a heat source of a seawater desalting device.
8. The use method of the low-quality waste heat utilization system of the steel plant according to claim 5, characterized in that: the method further comprises the following steps: and after the desalted water vapor is used as a heat source for seawater desalination, the obtained steam condensate water exchanges heat with blast furnace slag flushing water and high-temperature flue gas again, and after the steam is obtained by flash evaporation, the steam is used as a heat source of a seawater desalination device to be evaporated to obtain seawater distilled water.
Priority Applications (1)
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