CN210699554U - Three-section type whitening system based on catalytic cracking device - Google Patents
Three-section type whitening system based on catalytic cracking device Download PDFInfo
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- CN210699554U CN210699554U CN201920923232.2U CN201920923232U CN210699554U CN 210699554 U CN210699554 U CN 210699554U CN 201920923232 U CN201920923232 U CN 201920923232U CN 210699554 U CN210699554 U CN 210699554U
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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
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
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Abstract
The utility model discloses a three-section formula whitening system based on catalytic cracking unit, include: the system comprises a secondary flue gas heat exchanger, a washing tower, a primary flue gas heat exchanger, a flue gas heater and a boiler water system. In this way, the utility model relates to a three-section formula whitening system and processing technology based on catalytic cracking unit can effectual utilization retrieve flue gas low temperature waste heat and comdenstion water, reduces simultaneously and cancels even with fresh water quenching flue gas, reduces the flue gas moisture content from the source, reaches energy-conservation, water conservation, emission reduction, the purpose of whitening, improves the energy comprehensive utilization of device, reduces the energy consumption of device.
Description
Technical Field
The invention relates to the field of flue gas treatment, in particular to a three-section type whitening system based on a catalytic cracking device.
Background
At present, FCC (catalytic cracking) devices of domestic refining enterprises generally adopt a wet desulphurization process to carry out flue gas desulphurization. The desulfurization process generally adopts a water quenching method to reduce the temperature of medium-low temperature flue gas (150-200 ℃) from a waste heat boiler to the temperature required by desulfurization reaction, the quenched flue gas enters a desulfurization tower, and sulfur dioxide in the flue gas is removed by using an alkali liquor spraying, washing and neutralizing technology, and meanwhile, a large amount of water is gasified and then enters the flue gas, so that the temperature of the flue gas is reduced to be close to the water dew point temperature of the flue gas. The flue gas is washed by wet desulphurization alkali liquor and is in a saturated state and contains free water drops.
The flue gas quenching needs to consume a large amount of fresh water, and the water is gasified and then enters a desulfurizing tower along with the quenched flue gas to participate in the desulfurization reaction. And the last part enters an alkali liquor pool at the lower part of the desulfurizing tower along with the product after reaction, and the other part is discharged into the atmosphere along with the flue gas.
In the whole process, the flue gas is quenched from the outlet temperature of the boiler to the temperature required by the desulfurization reaction and then enters the desulfurization tower for reaction, and the waste heat (including sensible heat and latent heat of vapor in the flue gas) of the flue gas is wasted. In order to cool down the flue gas, a large amount of fresh water is also consumed, and the waste of precious water resources is also caused.
The wet smoke discharged from the chimney contacts with the ambient air with lower temperature, the smoke is cooled, the water vapor contained in the smoke is supersaturated and condensed in the process, and condensed water drops refract and scatter light, so that the smoke plume presents white or gray wet smoke plume (commonly called large white smoke, white fog and the like). When wet smoke is discharged, the lifting height of the smoke plume can be reduced, the diffusion effect is relatively poor, the landing concentration of pollutants near the chimney can be increased, the dust haze phenomenon is aggravated, and the visibility is influenced. When the environmental temperature is low and the demisting effect is poor, the chimney rain phenomenon is likely to occur, and the flue gas is not beneficial to lifting and diffusion, even the local acid rain is aggravated, and engineering facilities, buildings and the like are corroded. The phenomenon of wet smoke plume seriously affects the production and life of surrounding residents, weakens the satisfaction degree of the public on the environment protection work, and also makes requirements on the control of the wet smoke plume by relevant government departments of China and places.
Disclosure of Invention
The invention mainly solves the technical problem of providing a three-section type whitening system based on a catalytic cracking device, which has the advantages of high reliability, environmental protection, energy conservation, low cost and the like, and has wide market prospect in the application and popularization of flue gas treatment.
In order to solve the technical problems, the invention adopts a technical scheme that:
provides a three-section type whitening system based on a catalytic cracking device, which comprises a secondary flue gas heat exchanger, a washing tower, a primary flue gas heat exchanger, a flue gas heater and a boiler water system,
the secondary flue gas heat exchanger is used for receiving flue gas to be treated sent out of the boiler and is connected with the washing tower through a quick cooling flue gas pipeline, the washing tower is connected with the primary flue gas heat exchanger through a clean flue gas pipeline, the primary flue gas heat exchanger is connected with the flue gas heater, the boiler water system and the secondary flue gas heat exchanger through pipelines, the flue gas heater is connected with the boiler water system, and the secondary flue gas heat exchanger and the flue gas heater are connected with the alkali liquor pool through waste condensed water pipelines.
In a preferred embodiment of the invention, a booster fan is arranged between the boiler and the secondary flue gas heat exchanger.
In a preferred embodiment of the invention, a dust remover is arranged between the boiler and the secondary flue gas heat exchanger; the dust remover is connected with a return pipeline for conveying flue gas to be treated for heat exchange, and the return track penetrates through the flue gas heater and is connected with the washing tower.
In a preferred embodiment of the present invention, a dust remover is disposed between the booster fan and the secondary flue gas heat exchanger.
In a preferred embodiment of the present invention, a three-stage flue gas heat exchanger is arranged between the boiler and the dust remover.
In a preferred embodiment of the present invention, a third-stage flue gas heat exchanger is disposed between the booster fan and the dust remover, and the third-stage flue gas heat exchanger is connected to the second-stage flue gas heat exchanger.
In a preferred embodiment of the invention, the secondary flue gas heat exchanger is connected with a boiler thermal deaerator.
In a preferred embodiment of the invention, the boiler thermal deaerator is connected with the three-stage flue gas heat exchanger.
In a preferred embodiment of the present invention, the lye tank is connected with a lye pump, and the lye pump is connected with the washing tower or the waste liquid treatment system through a pipeline.
In a preferred embodiment of the present invention, a return pipe for conveying the flue gas to be treated for heat exchange is connected to the booster fan, and the return pipe passes through the flue gas heater and is connected to the scrubber or the dust remover.
The invention has the beneficial effects that: the method can effectively utilize and recover low-temperature waste heat and condensate water of the flue gas, simultaneously reduce or even cancel the use of fresh water for quenching the flue gas, reduce the moisture content of the flue gas from the source, achieve the purposes of saving energy and water, reducing emission and whitening, improve the comprehensive energy utilization rate of the device and reduce the energy consumption of the device.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:
FIG. 1 is a schematic diagram of a three-stage type whitening system embodiment based on a catalytic cracking unit, according to the present invention, wherein dirty flue gas is used as a circulating heat source;
FIG. 2 is a schematic diagram of a three-stage type whitening system based on a catalytic cracking unit according to an embodiment of the present invention, in which other circulating heat sources are used;
FIG. 3 is a schematic diagram of a structure of a second embodiment of a three-stage type whitening system based on a catalytic cracking unit, in which flue gas is returned from a flue gas heater to a dust remover;
FIG. 4 is a schematic diagram of the structure of the flue gas returning from the flue gas heater to the scrubber in the second embodiment of the three-stage type whitening system based on the catalytic cracking unit according to the present invention;
FIG. 5 is a schematic diagram of a three-stage type whitening system embodiment based on a catalytic cracking unit according to the present invention, in which other circulating heat sources are used;
FIG. 6 is a schematic diagram of a three-stage type whitening system embodiment based on a catalytic cracking unit according to the present invention, in which dirty flue gas is used as a circulating heat source;
FIG. 7 is a schematic structural diagram of a three-stage type whitening system based on a catalytic cracking unit according to a third embodiment of the present invention, wherein other circulating heat sources are used.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention comprises the following steps:
characteristics of mainstream smoke treatment technology and brief introduction of principle of mainstream smoke treatment technology
(1) The main elimination technology of the wet smoke plume is as follows:
(1.1) reducing the absolute moisture content of the flue gas;
(1.2) reducing the relative moisture content of the flue gas.
(2) According to the basic cause principle of the smoke plume phenomenon and in combination with actual production, the treatment means can be roughly divided into three categories: flue gas heating technology, flue gas condensation technology and flue gas condensation reheating technology.
(2.1) flue gas heating technology
The flue gas heating technology is to heat wet saturated flue gas before entering a chimney, raise the temperature of the wet flue gas, keep the absolute moisture content of the wet flue gas unchanged, and reduce the relative moisture content, so that the relative humidity of the flue gas is smaller than the saturated humidity after temperature rise, thereby achieving the technical requirement of eliminating smoke plume.
(2.2) flue gas condensation technology
The flue gas condensation technology is used for cooling wet saturated flue gas in front of an inlet of a chimney, so that the temperature of the wet flue gas is reduced, the moisture content is greatly reduced in the cooling process, and the absolute moisture content of the wet flue gas is reduced. The technology can recover a large amount of flue gas condensed water, and reduce the concentration of various pollutants such as smoke particles, SO3 and the like in the flue gas.
(2.3) flue gas condensation reheating technology
The flue gas condensation reheating technology is a combination of the two modes.
The elimination mechanism of the wet smoke plume is that the absolute moisture content in the wet smoke is reduced through temperature reduction, saturated water vapor in the smoke is separated out to form condensed water, and then the smoke is reheated to reduce the relative moisture content of the wet smoke, so that the smoke plume is eliminated.
The main reason for the 'plume phenomenon' commonly existing in FCC devices of refining enterprises adopting wet desulphurization technology is that liquid water and vapor water containing solid particles in flue gas desulfurized by a desulfurizing tower are mainly caused, and the fundamental reason is that the flue gas entering a chimney is saturated wet flue gas.
The FCC device integrated flue gas energy-saving water-saving emission-reducing de-whitening technology only considers the de-whitening measure adopted at the downstream of the desulfurizing tower, and basically de-whitens for de-whitening. The combination of the whitening, the recycling of the low-temperature waste heat of the flue gas, the recycling of the condensed water and the like is not considered, the energy conservation, the water conservation and the emission reduction are achieved while the whitening is carried out, the comprehensive energy utilization rate of the whole device is improved, and the energy consumption of the device is reduced.
Through the explanation of the related technology of the existing smoke plume treatment, and according to the characteristics of an FCC device and a desulfurization and denitrification process thereof, the application provides a three-section type whitening system based on a catalytic cracking device and a treatment process thereof, and through a method of 'quenching before a tower, deep cooling after the tower and smoke reheating', the low-temperature waste heat of the smoke is recovered while whitening is carried out; fresh water for smoke abatement gas quenching is reduced and even taken, namely, the moisture content of smoke is reduced from the source; recovering purified flue gas condensate water as boiler feed water; the heating boiler softens water to reduce the consumption of deoxygenated steam, so that the aims of saving energy and water, reducing emission and removing white are fulfilled, the comprehensive utilization rate of energy of the device is improved, and the energy consumption of the device is reduced.
Although the technology is a flue gas 'whitening' technology developed for FCC devices of refineries, the technology is also applicable to industrial furnaces and boilers of other devices of refineries and other industries which adopt wet desulphurization, and only the cold medium mainly used for condensing the flue gas and the heat medium mainly used for reheating the flue gas need to be changed.
Detailed description of the preferred embodiment
Referring to FIGS. 1-2, a system and process for de-whitening without a dust catcher
A three-section type white removing system based on a catalytic cracking device comprises a secondary flue gas heat exchanger 3, a washing tower 4, a primary flue gas heat exchanger 5, a flue gas heater 6, a boiler 1 and a boiler water system 7.
The flue gas heater is connected with the boiler water system through a purified condensed water pipeline, and meanwhile, the waste gas at the temperature of 50-80 ℃ is sent to a chimney 10 through a discharge pipeline to be discharged; the secondary flue gas heat exchanger and the flue gas heater are connected with an alkali liquor pool 8 through a waste condensed water pipeline, an alkali liquor pump 9 extracts a solution in the alkali liquor pool and conveys the solution to the washing tower, the alkali liquor pump also can extract and convey the solution in the alkali liquor pool to a next waste liquid treatment system, and the secondary flue gas heat exchanger is connected with a boiler thermal deaerator 11.
The booster fan 2 or the boiler is connected with the flue gas heater through a pipeline, and the flue gas heater can also be connected with other circulating heat sources 12 through pipelines so as to meet the heat exchange requirement in the flue gas heater.
The second-stage flue gas heat exchanger is used for receiving flue gas to be treated sent out of the boiler and is connected with the washing tower through a rapid cooling flue gas pipeline, and the washing tower is connected with the first-stage flue gas heat exchanger through a clean flue gas pipeline. When the flue gas pressure from the boiler is not enough to overcome the increased flue gas pressure caused by adding the primary and secondary flue gas heat exchangers and the flue gas heater in the system, a booster fan can be additionally arranged between the boiler and the secondary flue gas heat exchanger.
The first-stage flue gas heat exchanger is connected with the flue gas heater through a dehydration flue gas pipeline, is connected with the boiler water system through a purified condensed water pipeline, and is connected with the second-stage flue gas heat exchanger through a boiler water supply pipeline.
The main process steps of the system comprise:
the method comprises the following steps that medium-low-temperature (150-200 ℃) flue gas from a waste heat boiler enters a secondary flue gas heat exchanger after being pressurized by a booster fan, the flue gas exchanges heat with boiler feed water from a primary flue gas heat exchanger, the temperature of the flue gas is reduced to the temperature required by desulfurization reaction (part of water vapor contained in the flue gas is condensed and removed, and simultaneously part of SOx and particulate matters in the flue gas are absorbed and adsorbed by condensed water, the flue gas is primarily purified, and the absolute moisture content of the flue gas is primarily reduced), and then the flue gas enters a washing tower for desulfurization and denitrification. -saving flue gas cooling water
Purified flue gas from a washing tower enters a primary flue gas heat exchanger, exchanges heat with boiler feed water at normal temperature (-30 ℃) from a boiler water system and is cooled to a temperature far lower than the dew point of the water, most of water vapor contained in the flue gas is condensed, the absolute moisture content of the flue gas is reduced, dry flue gas from the primary flue gas heat exchanger enters a flue gas preheater, exchanges heat with medium-low temperature flue gas from a booster fan, is heated to 50-80 ℃ (the relative moisture content of the flue gas is reduced, and the diffusion capacity of the flue gas is improved), and enters a chimney to be discharged into the atmosphere. -de-whitening
And (3) heating the boiler feed water to 50-90 ℃ after heat exchange of the two-stage flue gas heat exchanger, and removing oxygen from the boiler by using a thermal deaerator. The high-quality steam consumption for the thermal deoxidization of boiler water can be reduced. Saving steam
Dirty flue gas from a boiler is subjected to heat exchange with boiler water in a secondary flue gas heat exchanger to generate sulfur-containing and dust-containing flue gas condensate water (dirty condensate water), the dirty flue gas is subjected to heat exchange with low-temperature purified flue gas in a flue gas heater to generate sulfur-containing and dust-containing flue gas condensate water (dirty condensate water), the sulfur-containing and dust-containing flue gas condensate water and the dirty condensate water are discharged into a desulfurization system alkali liquor pool through a pipeline to perform neutralization reaction, and the neutralized condensate water and washed liquid from a washing tower are discharged into subsequent treatment facilities through the pipeline to be subjected to centralized treatment and discharge.
Purified flue gas condensate water generated by flue gas condensation in the primary flue gas heat exchanger is conveyed to a boiler water system through a pipeline to be used as boiler feed water. Reduce the consumption of raw water of the boiler. -water saving.
The medium-low temperature flue gas from the booster fan is cooled to the desulfurization reaction temperature after being heated in the flue gas heater, and then enters the washing tower.
The smoke outlet section of the primary smoke heat exchanger is provided with a demister, so that most of water mist drops contained in smoke can be removed, and the reheating load of subsequent smoke is reduced.
If the flue gas pressure from the waste heat boiler is enough to overcome the increased flue gas pressure drop caused by adding the primary and secondary flue gas heat exchangers and the flue gas heater in the system, the booster fan can be omitted.
The medium for cooling and quenching the flue gas can be normal-temperature boiler water, and can also be other cold sources meeting the requirements, such as boiler raw water, cooling water in a device or a plant area, domestic water, heating water, normal-temperature air and the like.
The medium for heating and purifying the flue gas can be heated by other heat sources besides the dirty flue gas from the boiler, such as superheated steam or saturated steam; or boiler feed water heated by thermal deoxidization or heating media from other sources are adopted for heating.
The dirty condensate water generated by the dirty flue gas can be also provided with an independent treatment system, and is discharged after reaching the standard, or is sent into a sewage treatment system for centralized treatment and discharge after being pretreated, or is directly sent into the sewage treatment system for treatment.
Detailed description of the invention
Referring to FIGS. 3-5, a whitening system and process with a low temperature scrubber
A three-section type whitening system based on a catalytic cracking device comprises a low-temperature dust remover 13, a secondary flue gas heat exchanger, a washing tower, a primary flue gas heat exchanger, a flue gas heater, a boiler water system and a tertiary flue gas heat exchanger 14.
The boiler is connected with the low-temperature dust remover, and when the pressure of the flue gas from the boiler is not enough to overcome the pressure of the flue gas increased by adding the primary and secondary flue gas heat exchangers and the flue gas heater in the system, a booster fan can be additionally arranged between the boiler and the low-temperature dust remover. The second-stage flue gas heat exchanger connected with the low-temperature dust remover is connected with the washing tower through a quick-cooling flue gas pipeline, and the washing tower is connected with the first-stage flue gas heat exchanger through a clean flue gas pipeline.
The primary flue gas heat exchanger is connected with the flue gas heater through a dehydration flue gas pipeline, the primary flue gas heat exchanger is connected with the boiler water system through a purified condensed water pipeline, and the primary flue gas heat exchanger is connected with the secondary flue gas heat exchanger through a boiler water supply pipeline.
The flue gas heater is connected with the boiler water system through a purified condensed water pipeline, and meanwhile, the waste gas at the temperature of 50-80 ℃ is sent to a chimney through a discharge pipeline to be discharged; the booster fan or the boiler is connected with the flue gas heater through a pipeline, and the flue gas heater can also be connected with other circulating heat sources through a pipeline so as to meet the heat exchange requirement in the flue gas heater.
The secondary flue gas heat exchanger and the flue gas heater are respectively connected with an alkali liquor pool through a waste condensed water pipeline, the alkali liquor pump pumps the solution in the alkali liquor pool and conveys the solution to the washing tower, and the alkali liquor pump can also pump and convey the solution in the alkali liquor pool to a next waste liquid treatment system; the three-level flue gas heat exchanger is connected with the boiler thermal deaerator, and the three-level flue gas heat exchanger is connected with the second-level flue gas heat exchanger through a boiler water supply pipeline.
The main work flow of the system comprises the following steps:
the medium-low temperature (150-200 ℃) flue gas from the waste heat boiler enters a three-stage flue gas heat exchanger after being pressurized by a booster fan, exchanges heat with boiler feed water from a two-stage flue gas heat exchanger, the temperature of the flue gas is reduced to the operation temperature of a low-temperature dust remover, and the flue gas enters the low-temperature dust remover to remove smoke dust particles in the flue gas.
The flue gas enters a secondary flue gas heat exchanger after dust removal, exchanges heat with boiler feed water from a primary flue gas heat exchanger, and enters a washing tower for desulfurization and denitrification after the temperature of the flue gas is reduced to the temperature required by desulfurization reaction (part of water vapor contained in the flue gas is removed by condensation, and simultaneously, part of SOx and particulate matters in the flue gas is absorbed by condensed water, so that the flue gas is primarily purified, and the absolute moisture content of the flue gas is primarily reduced). And flue gas cooling water is saved.
The purified flue gas from the washing tower enters a primary flue gas heat exchanger, exchanges heat with normal-temperature boiler water from a boiler water system and is cooled to a temperature far lower than the dew point of the water, so that most of water vapor contained in the flue gas is condensed, and the absolute moisture content of the flue gas is reduced.
The dry flue gas from the primary flue gas heat exchanger enters a flue gas heater, exchanges heat with medium-low temperature flue gas from a booster fan/low-temperature dust remover, is heated to 50-80 ℃ (the relative moisture content of the flue gas is reduced, and the diffusion capacity of the flue gas is improved), and enters a chimney to be discharged into the atmosphere. -de-whitening
The medium-low temperature flue gas from the booster fan has two routes after the dry flue gas is heated in the flue gas heater; firstly, cooling to the operating temperature of the low-temperature dust remover, and removing smoke dust particles in the flue gas in the low-temperature dust remover; secondly, the temperature is reduced to the temperature of the desulfurization reaction, and the reaction product enters a washing tower.
And (3) heating the boiler feed water to 50-90 ℃ after heat exchange of the boiler feed water by the three-stage flue gas heat exchanger, and removing oxygen by a boiler thermal deaerator. The high-quality steam consumption for the thermal deoxidization of boiler water can be reduced. Saving steam
Dirty flue gas from a boiler is subjected to heat exchange with boiler water in a secondary flue gas heat exchanger to generate sulfur-containing and dust-containing flue gas condensate water (dirty condensate water), the dirty flue gas is subjected to heat exchange with low-temperature purified flue gas in a flue gas heater to generate sulfur-containing and dust-containing flue gas condensate water (dirty condensate water), the sulfur-containing and dust-containing flue gas condensate water and the dirty condensate water are discharged into a desulfurization system alkali liquor pool through a pipeline to perform neutralization reaction, and the neutralized condensate water and washed liquid from a washing tower are discharged into subsequent treatment facilities through the pipeline to be subjected to centralized treatment and discharge.
Purified flue gas condensate water generated by flue gas condensation in the primary flue gas heat exchanger is conveyed to a boiler water system through a pipeline to be used as boiler feed water. Reduce the consumption of raw water of the boiler. -water saving.
The smoke outlet section of the primary smoke heat exchanger is provided with a demister, so that most of water mist drops contained in smoke can be removed, and the reheating load of subsequent smoke is reduced.
The flue gas pressure from the waste heat boiler is enough to overcome the increased flue gas pressure drop caused by adding a primary flue gas heat exchanger, a secondary flue gas heat exchanger and a flue gas heater in the system, and a booster fan can be omitted.
The medium for cooling and quenching the flue gas can be normal-temperature boiler water, and can also be other cold sources meeting the requirements, such as boiler raw water, cooling water in a device or a plant area, domestic water, heating water, normal-temperature air and the like.
The medium for heating and purifying the flue gas can be heated by other heat sources besides the dirty flue gas from the boiler, such as superheated steam or saturated steam; or boiler feed water heated by thermal deoxidization or heating media from other sources are adopted for heating.
The dirty condensate water generated by the dirty flue gas can be also provided with an independent treatment system, and is discharged after reaching the standard, or is sent into a sewage treatment system for centralized treatment and discharge after being pretreated, or is directly sent into the sewage treatment system for treatment.
Detailed description of the preferred embodiment
Referring to FIGS. 6-7, a de-whitening system with a high temperature dust collector and a process
A three-section type whitening system based on a catalytic cracking device comprises a high-temperature dust remover 15, a secondary flue gas heat exchanger, a washing tower, a primary flue gas heat exchanger, a flue gas heater, a boiler and a boiler water system.
The boiler is connected with the high-temperature dust remover, and when the pressure of the flue gas from the boiler is insufficient to overcome the pressure of the flue gas increased by adding the primary and secondary flue gas heat exchangers and the flue gas heater in the system, a booster fan can be additionally arranged between the boiler and the high-temperature dust remover. And the second-stage flue gas heat exchanger connected with the high-temperature dust remover is connected with the washing tower through a quenching flue gas pipeline, and the washing tower is connected with the first-stage flue gas heat exchanger through a clean flue gas pipeline.
The primary flue gas heat exchanger is connected with the flue gas heater through a dehydration flue gas pipeline, the primary flue gas heat exchanger is connected with the boiler water system through a purified condensed water pipeline, and the primary flue gas heat exchanger is connected with the secondary flue gas heat exchanger through a boiler water supply pipeline.
The flue gas heater is connected with the boiler water system through a purified condensed water pipeline, and meanwhile, the waste gas at the temperature of 50-80 ℃ is sent to a chimney through a discharge pipeline to be discharged; the booster fan or the boiler is connected with the flue gas heater through a pipeline, and the flue gas heater can also be connected with other circulating heat sources through a pipeline so as to meet the heat exchange requirement in the flue gas heater.
The secondary flue gas heat exchanger and the flue gas heater are respectively connected with an alkali liquor pool through a waste condensed water pipeline, the alkali liquor pump pumps the solution in the alkali liquor pool and conveys the solution to the washing tower, and the alkali liquor pump can also pump and convey the solution in the alkali liquor pool to a next waste liquid treatment system; and the secondary flue gas heat exchanger is connected with a thermal deaerator of the boiler.
The main work flow of the system comprises the following steps:
the medium-low temperature (150-200 ℃) flue gas from the waste heat boiler enters a dust remover to remove smoke dust particles in the flue gas after being pressurized by a booster fan.
The flue gas enters a secondary flue gas heat exchanger after dust removal, exchanges heat with boiler feed water from a primary flue gas heat exchanger, and enters a washing tower for desulfurization and denitrification after the temperature of the flue gas is reduced to the temperature required by desulfurization reaction (part of water vapor contained in the flue gas is removed by condensation, and SOx and particulate matters in the flue gas are absorbed and adsorbed by condensed water, so that the flue gas is primarily purified, and the absolute moisture content of the flue gas is primarily reduced). -saving flue gas cooling water
Purified flue gas from the washing tower enters a primary flue gas heat exchanger, exchanges heat with boiler feed water from a boiler water system at normal temperature (-30 ℃) and is cooled to a temperature far lower than the dew point of the water, so that most of water vapor contained in the flue gas is condensed, and the absolute moisture content of the flue gas is reduced.
The dry flue gas from the primary flue gas heat exchanger enters a flue gas preheater, exchanges heat with the medium-low temperature flue gas from a booster fan/high-temperature dust remover, is heated to 50-80 ℃ (the relative moisture content of the flue gas is reduced, and the diffusion capacity of the flue gas is improved), and enters a chimney to be discharged into the atmosphere. -de-whitening
And (3) heating the boiler feed water to 50-90 ℃ after heat exchange of the two-stage flue gas heat exchanger, and removing oxygen from the boiler by using a thermal deaerator. The high-quality steam consumption for the thermal deoxidization of boiler water can be reduced. Saving steam
The dedusting flue gas from the high-temperature deduster is heated in the flue gas heater and then enters the washing tower.
Dirty flue gas from a boiler is subjected to heat exchange with boiler water in a secondary flue gas heat exchanger to generate sulfur-containing and dust-containing flue gas condensate water (dirty condensate water), and the dirty flue gas is subjected to heat exchange with low-temperature purified flue gas in a flue gas heater to generate sulfur-containing and dust-containing flue gas condensate water (dirty condensate water), the sulfur-containing and dust-containing flue gas condensate water and the dirty condensate water are discharged into a desulfurization system alkali liquor pool through a pipeline to perform neutralization reaction, and the neutralized condensate water and washed liquid from a washing tower are discharged into a subsequent treatment facility through the pipeline to be treated and discharged.
Purified flue gas condensate water generated by flue gas condensation in the primary flue gas heat exchanger is conveyed to a boiler water system through a pipeline to be used as boiler feed water. Reduce the consumption of raw water of the boiler. -saving water
The smoke outlet section of the primary smoke heat exchanger is provided with a demister, so that most of water mist drops contained in smoke can be removed, and the reheating load of subsequent smoke is reduced.
The flue gas pressure from the waste heat boiler is enough to overcome the increased flue gas pressure drop caused by adding a primary flue gas heat exchanger, a secondary flue gas heat exchanger and a flue gas heater in the system, and a booster fan can be omitted.
The medium for cooling and quenching the flue gas can be normal-temperature boiler water, and can also be other cold sources meeting the requirements, such as boiler raw water, cooling water in a device or a plant area, domestic water, heating water, normal-temperature air and the like.
The medium for heating and purifying the flue gas can be heated by other heat sources besides the dirty flue gas from the boiler, such as superheated steam or saturated steam; or boiler feed water heated by thermal deoxidization or heating media from other sources are adopted for heating.
The dirty condensate water generated by the dirty flue gas can be also provided with an independent treatment system, and is discharged after reaching the standard, or is sent into a sewage treatment system for centralized treatment and discharge after being pretreated, or is directly sent into the sewage treatment system for treatment.
The three-section type whitening system based on the catalytic cracking device and the treatment process thereof have the beneficial effects that:
1. before the flue gas enters the washing tower, the flue gas is pre-condensed, the flue gas is preliminarily purified, the consumption of alkali liquor for washing the washing tower is reduced, the load of the washing tower is reduced, and the operation cost is saved;
2. the boiler water is heated by the waste heat of the flue gas, and the low-temperature heat energy of the flue gas wasted by the waste is recovered, so that the energy is saved;
3. the link of quenching flue gas by using fresh water before entering the washing tower is cancelled, so that the consumption of fresh cooling water is zero, and water is saved;
4. the heated boiler water is sent to a boiler thermal deoxidization system, so that steam for thermal deoxidization is reduced, and high-quality steam is saved;
5. the purified flue gas is further condensed to reduce the absolute moisture content of the flue gas, and the generated 'clean' condensed water can be sent to a boiler water treatment system to be used as raw water, so that the consumption of the raw water of the boiler is reduced, and water is saved;
6. the flue gas is subjected to rapid cooling before ① towers, deep cooling after ② towers and ③ flue gas reheating, and the three-stage technology achieves the aim of flue gas energy-saving, water-saving, steam-saving, emission-reduction and whitening-removal.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A three-section type whitening system based on a catalytic cracking device is characterized by comprising a secondary flue gas heat exchanger, a washing tower, a primary flue gas heat exchanger, a flue gas heater and a boiler water system,
the secondary flue gas heat exchanger is used for receiving flue gas to be treated sent out of the boiler and is connected with the washing tower through a quick cooling flue gas pipeline, the washing tower is connected with the primary flue gas heat exchanger through a clean flue gas pipeline, the primary flue gas heat exchanger is connected with the flue gas heater, the boiler water system and the secondary flue gas heat exchanger through pipelines, the flue gas heater is connected with the boiler water system, and the secondary flue gas heat exchanger and the flue gas heater are connected with the alkali liquor pool through waste condensed water pipelines.
2. The catalytic cracking unit-based three-stage type whitening system according to claim 1, characterized in that a booster fan is arranged between the boiler and the secondary flue gas heat exchanger.
3. The catalytic cracking unit-based three-stage type whitening system according to claim 1, characterized in that a dust remover is arranged between the boiler and the secondary flue gas heat exchanger; and the dust remover is connected with a return pipeline for conveying flue gas to be treated for heat exchange, and the return pipeline penetrates through the flue gas heater and is connected with the washing tower.
4. The catalytic cracking unit-based three-stage type whitening system according to claim 2, characterized in that a dust remover is arranged between the booster fan and the secondary flue gas heat exchanger.
5. The catalytic cracking unit-based three-stage type whitening system according to claim 3, characterized in that a three-stage flue gas heat exchanger is arranged between the boiler and the dust remover.
6. The catalytic cracking unit-based three-stage type whitening system according to claim 4, wherein a three-stage flue gas heat exchanger is arranged between the booster fan and the dust remover, and the three-stage flue gas heat exchanger is connected with the two-stage flue gas heat exchanger.
7. The catalytic cracking unit-based three-stage type whitening system according to claim 6, wherein the secondary flue gas heat exchanger is connected with a boiler thermal deaerator.
8. The catalytic cracking unit-based three-stage whitening system according to claim 7, wherein the boiler thermal deaerator is connected with the three-stage flue gas heat exchanger.
9. The catalytic cracking unit-based three-stage type whitening system according to claim 1, wherein a lye pump is connected to the lye pool and is connected to the scrubber or the waste liquid treatment system through a pipeline.
10. The catalytic cracking unit-based three-stage type whitening system according to claim 2, 4 or 6, characterized in that a return pipe for conveying the flue gas to be treated for heat exchange is connected to the booster fan, and the return pipe passes through the flue gas heater and is connected to the scrubber or the dust remover.
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| CN201920923232.2U CN210699554U (en) | 2019-06-19 | 2019-06-19 | Three-section type whitening system based on catalytic cracking device |
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| CN201920923232.2U CN210699554U (en) | 2019-06-19 | 2019-06-19 | Three-section type whitening system based on catalytic cracking device |
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