CN114484489A - Air mixing and heating process for eliminating white smoke of catalytic cracking - Google Patents

Air mixing and heating process for eliminating white smoke of catalytic cracking Download PDF

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Publication number
CN114484489A
CN114484489A CN202111681595.8A CN202111681595A CN114484489A CN 114484489 A CN114484489 A CN 114484489A CN 202111681595 A CN202111681595 A CN 202111681595A CN 114484489 A CN114484489 A CN 114484489A
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China
Prior art keywords
inner cylinder
section
flue gas
boiler water
cylinder
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CN202111681595.8A
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Chinese (zh)
Inventor
涂林
卢新军
李克海
刘玉英
柳杨
孙晓怡
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Sinopec Engineering Group Co Ltd
Sinopec Ningbo Engineering Co Ltd
Sinopec Ningbo Technology Research Institute
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Sinopec Engineering Group Co Ltd
Sinopec Ningbo Engineering Co Ltd
Sinopec Ningbo Technology Research Institute
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Priority to CN202111681595.8A priority Critical patent/CN114484489A/en
Publication of CN114484489A publication Critical patent/CN114484489A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/08—Arrangements of devices for treating smoke or fumes of heaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
    • F23J15/04—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material using washing fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/20—Sulfur; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
    • F23J2900/15081—Reheating of flue gases
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chimneys And Flues (AREA)

Abstract

The invention relates to a heating process for eliminating white mixed air in catalytic cracking flue gas, which is characterized in that heat is taken from flue gas through pressurized boiler water circulation for heating, and the pressure is stabilized through a pressure stabilizing buffer tank, boiler water backwater is always kept at 20-50 ℃ above an acid dew point, so that the problems that the heat exchange is directly carried out by utilizing air and flue gas in the prior art, or the acid dew point corrosion of a flue gas heat exchanger is easily caused by temperature fluctuation due to unstable pressure when boiler water is used for heat taking in the prior art can be effectively avoided; the waste heat of the flue gas is fully utilized, and additional heat energy is not needed; boiler water is circularly heated, no additional boiler water is required to be supplemented, nitrogen is only used for stabilizing pressure and is not consumed, only fan power consumption is increased, flow energy consumption is low, and operation cost is low; the flue gas is discharged from the top of the chimney after being overheated, the height of the air mixing position is reduced as far as possible on the premise of meeting the national standard, the height of a supporting steel structure and the span of a steel column are reduced, the occupied area is reduced, additional load is not generated on the original tower equipment, and the project investment and the implementation difficulty are reduced.

Description

Air mixing heating process for eliminating white smoke of catalytic cracking
Technical Field
The invention relates to the technical field of environmental protection equipment, in particular to a catalytic cracking flue gas white-eliminating mixed air heating process.
Background
The flue gas of a catalytic cracking device is always a key environment-friendly monitoring point of oil refining enterprises, most domestic oil refining enterprises establish a large amount of regenerated flue gas desulfurization and denitration devices in a short period after 2010, the flow adopted in the initial stage is mostly two-section type chilling alkali washing, the demisting efficiency of equipment in a tower is lower, the exhaust temperature is high, absorption liquid is in direct contact with high-temperature flue gas, the moisture content of the flue gas is increased, the flue gas is humidified and cooled to a saturated state, purified flue gas with saturated humidity is not overheated and is discharged into the atmosphere from a chimney, the discharged wet flue gas is in contact with and mixed with lower-temperature ambient air, the flue gas is rapidly cooled in the process, the contained water vapor in the flue gas is supersaturated and condensed, the condensed water drops refract and scatter light, the light transmittance is reduced, and the phenomenon of white smoke plume visible to the naked eyes appears. When white smoke occurs, particularly in winter, the environmental temperature is low, and besides the social influence caused by visual pollution, the white smoke falls to the periphery of the wet washing tower in a rainfall manner, so that salt deposition and corrosion on the surface of equipment are caused.
Meanwhile, due to the limitation of acid dew point, the exhaust gas temperature of the catalytic cracking low-temperature economizer is mostly 160-220 ℃, the outlet temperature of part of devices is even more than 280 ℃, and the exhaust gas temperature is higher and the amount of partial water is large, so that energy waste is caused to a certain extent due to the fact that the exhaust gas temperature is higher and the temperature of part of the exhaust gas can be reduced only by water spraying chilling during desulfurization.
The transformation of white smoke elimination usually changes the temperature or humidity of smoke, avoids the phenomenon of 'white smoke' caused by supersaturation and condensation due to the reduction of smoke temperature in the process of mixing smoke and ambient air, namely, the smoke temperature is reduced through smoke condensation, the condensed moisture is extracted, the absolute moisture content of smoke exhaust is reduced, and the temperature difference between the smoke and the ambient air is reduced; and then the flue gas is heated to raise the temperature of the flue gas, so that the flue gas at the outlet of the chimney is overheated, and the parameters are far away from the saturation curve, thereby eliminating white smoke.
The flue gas reheating is divided into direct heating and indirect heating.
When the flue gas is directly heated, the flue gas is directly heated by steam, heat medium water or electricity in the chimney section, or the flue gas before purification is directly heated and purified by the heat medium water, the heat exchangers are required to be arranged at the top of the chimney in the overheating modes, the load of the original absorption tower and the frame and the like can be influenced for the reconstruction device, the implementation difficulty is very high, the problem of acid dew point corrosion is also involved by the heat medium water after the heat medium water is used for heating the flue gas before purification, and the steam, the heat medium water or the electricity causes very large new energy consumption;
the indirect heating usually preheats air through heat medium water or steam, and then mixes the hot air boosted by the fan into the flue gas at the tail end of the chimney to achieve the effect of raising the temperature of the flue gas, or mixes the air into the flue gas at the tail end of the chimney after the air is heated from the flue gas before purification. The indirectly heated heat exchange equipment is uniformly arranged on the ground or a low-level frame, the practicability is higher, but the air mixing position is usually required to be behind a CEMS sampling point and needs to meet the national standard HJ 75 fixed pollution source flue gas (SO)2NOx and particulate matters) emission continuous monitoring technical specification, the requirement of the straight pipe section of the front four and the rear two of the chimney is that due to the characteristic of large caliber of the chimney, the air mixing position is often more than 50 meters, and in addition, the diameter of the hot air pipe is 1-2 meters, so that the challenges are provided for the height, the cost and the practicability of a support steel structure of the tower-attached hot air pipe, and in the same way, the problem of acid dew point corrosion of the gas-gas heat exchanger is also serious by adopting a flue gas heat taking air mixing mode before purification.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art, and provides a catalytic cracking flue gas white-eliminating mixed air heating process, which reduces energy consumption and process water supplement as much as possible in the white-eliminating and transforming process of the prior catalytic cracking device, avoids dew point corrosion, and reduces the height of a mixed air position as much as possible on the premise of meeting the requirement of a CEMS point straight pipe section in national standards, thereby reducing the height of a supporting steel structure and the span of a steel column, reducing the occupied area, generating no additional load on the prior tower equipment, and reducing the project investment and the implementation difficulty.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a catalytic cracking flue gas white-eliminating mixed air heating process comprises the following steps:
the temperature of the flue gas sent from the catalytic cracking section is 180-;
the flue gas after heat exchange is carried out at the temperature of 150 ℃ and 220 ℃, and is sent into any existing washing tower for desulfurization and dust removal;
boiler water with the temperature of 100-200 ℃ is firstly sent into a pressure-stabilizing buffer tank, the pressure is maintained at 1.5-2.5 MPaG by medium-pressure nitrogen, the boiler water from the pressure-stabilizing buffer tank is sent into a boiler water circulating system, is pressurized by a boiler water circulating pump and then is sent into a flue gas heat exchanger for heat extraction, and is sent to an air heater after being heated to 160-200 ℃, and normal-temperature air sent by a fan is used for heating; the heat released by the boiler water is cooled to 150-160 ℃ and then returns to the boiler water circulating pump for circulation;
the temperature of hot air at the outlet of the air heater is 100-150 ℃, and the hot air and the purified flue gas at the temperature of 45-60 ℃ after the desulfurization and the dust removal are mixed and superheated to 70-90 ℃ in a chimney, and then the mixture is discharged into the atmosphere.
Preferably, after the boiler water is subjected to heat taking and heat releasing circulation, a 10-25 m lift is provided by a boiler water circulating pump to overcome resistance drop of pipelines and equipment, the pressure stabilizing buffer tank does not participate in boiler water circulation, only system pressure and liquid level are maintained, and additional continuous boiler water supplement is not needed.
Preferably, boiler water walks on the pipe side, flue gas walks on the shell side among the gas heater, and gas heater's tube bank is 2 grades of series connections, and every grade can be cut out alone to set up boiler water inlet and outlet independently.
Preferably, a bypass for adjusting and controlling the temperature of the boiler water to avoid the high temperature to cause vaporization of the boiler water is arranged on the boiler water pipe side and the flue gas side.
Preferably, the boiler water side pipeline of the air heater is provided with a rapid temperature rise bypass for ensuring that the temperature of the boiler water is lower than the rapid body temperature when the device is driven to avoid dew point corrosion.
The chimney of the invention comprises:
the outer cylinder comprises an upper section of the outer cylinder and a lower section of the outer cylinder which are mutually connected from top to bottom, the upper section of the outer cylinder is a circular cylinder, the lower section of the outer cylinder is a conical reducing section with the inner diameter gradually increasing from top to bottom, and a hot air mixing inlet is formed in the lower section of the outer cylinder;
the inner cylinder is sleeved in the outer cylinder and comprises an upper inner cylinder section, a middle inner cylinder section and a lower inner cylinder section which are mutually connected from top to bottom, the upper inner cylinder section and the middle inner cylinder section are circular cylinders, the lower inner cylinder section is a conical reducing section with the inner diameter gradually increasing from top to bottom, and the lower inner cylinder section is positioned at the lower part of the lower outer cylinder section;
the diameter of the inner cylinder is smaller than that of the outer cylinder, a cavity for the circulation of preheated air is formed between the inner cylinder and the outer cylinder, and a channel for the circulation of flue gas for the desulfurization and dust removal of the washing tower is formed in the inner space of the inner cylinder.
Preferably, the cross-sectional area of the cavity is 1 to 1.5 times the sum of the cross-sectional areas of the hot air mixing openings on the outer cylinder.
Preferably, the height of the lower section of the inner cylinder is lower than that of the lower section of the outer cylinder, and the reducing gradient of the lower section of the inner cylinder is greater than or equal to that of the lower section of the outer cylinder. Because the existence of the height difference and the gradient difference increases the cavity gap between the conical reducing sections with the inner diameters gradually increasing from top to bottom, the impact of hot air on the inner cylinder of the chimney can be effectively slowed down, and the uniform distribution and the steady flow of the hot air are realized.
Preferably, the top of the cavity is provided with a top ring plate, one side of the top ring plate is welded with the inner wall surface of the upper section of the outer barrel, the other side of the top ring plate is welded with the top surface of the upper section of the inner barrel, and the top end of the upper section of the inner barrel is provided with a square hole. The sum of the sectional areas of the square holes is larger than that of the cavity.
Preferably, a bottom ring plate is arranged at the bottom end of the lower section of the inner cylinder, one side of the bottom ring plate is welded with the inner wall surface of the body section of the washing tower barrel, the other side of the bottom ring plate is welded with the bottom end of the lower section of the inner cylinder, and in order to provide enough strength for supporting the inner cylinder, an inner cylinder reinforcing rib plate for supporting the inner cylinder is further arranged below the bottom ring plate.
Preferably, the lower part of the upper section of the inner cylinder is provided with a plurality of first sampling ports, the first sampling ports comprise CEMS sampling ports and/or manual sampling ports, and the first sampling ports penetrate through the cavity and are only directly communicated with the inner cylinder. The first sampling port is positioned below the square hole of the upper section of the inner barrel, and the distance from the first sampling port to the lower section of the inner barrel is 4 times of the diameter of the inner barrel, and the distance from the first sampling port to the lower edge of the square hole of the upper section of the inner barrel is 2 times of the diameter of the inner barrel. The structure meets the requirements of national standards or local standards on the front and rear straight pipe sections of particulate matters and gas pollutants, and determines the length of the inner cylinder of the chimney and the height of the lower boundary of the square hole at the upper section of the inner cylinder from the requirements, so that air mixing after CEMS sampling under the premise of meeting the national standards is realized.
Preferably, the middle part of the upper section of the outer barrel is provided with a second manual sampling port, and the second manual sampling port is only connected with the cavity.
Preferably, an inspection manhole is further arranged on the lower section of the outer barrel at the lower part of the outer barrel, and inspection drainage condensation ports which are symmetrically distributed are arranged on the bottom annular plate at the bottom of the cavity.
In order to solve the problem of thermal expansion caused by temperature difference of different media in the inner cylinder, the outer cylinder and the cavity, a refractory ceramic fiber cotton layer with the same thickness as the inner cylinder is arranged between the upper section of the inner cylinder and the middle section of the inner cylinder, an inner ring plate and an outer ring plate are arranged on two sides of the fiber cotton layer, and the bottom surfaces of the lower parts of the inner ring plate and the outer ring plate are welded and fixed with the inner wall surface and the outer wall surface of the middle section of the inner cylinder. Preferably, in order to facilitate the installation of the upper section of the inner cylinder, the upper end of the inner annular plate is bent at a small angle towards the inside, and similarly, the upper end of the outer annular plate is bent at a small angle towards the outside.
In order to better support the inner cylinder, a plurality of connecting plates are arranged on the upper section of the inner cylinder, penetrate through the inner cylinder and the outer cylinder and are welded and sealed with the inner cylinder and the outer cylinder. Preferably, the inner side of the inner cylinder is provided with reinforcing ribs from top to bottom.
Compared with the prior art, the invention has the advantages that:
1. the boiler water is heated by heat extraction from the flue gas through the circulation of pressurized boiler water, and the pressure is stabilized through a pressure stabilizing buffer tank, the backwater of the boiler water is always kept 20-50 ℃ above the acid dew point, so that the problems that the heat exchange is directly carried out by utilizing air and the flue gas in the prior art, or the acid dew point corrosion of a flue gas heat exchanger is easily caused by temperature fluctuation due to unstable pressure in the prior art by utilizing boiler water for heat extraction can be effectively avoided;
2. the waste heat of the flue gas is fully utilized, and additional heat energy is not required to be supplemented; boiler water is circularly heated, no additional boiler water is required to be supplemented, nitrogen is only used for stabilizing pressure and is not consumed, only fan power consumption is increased, flow energy consumption is low, and operation cost is low;
3. the invention effectively solves the problem that hot air is mixed at a high point when the existing device is used for white smoke elimination transformation, the connecting position of the hot air is reduced to the front of a CEMS sampling port to the maximum extent, and the actual mixing position of the hot air and the flue gas meets the requirements of national standard on a CEMS sampling port straight pipe section, so that the length of a large-caliber hot air pipeline is effectively reduced, the additional load of the original washing tower is reduced, the height of a steel frame for supporting an air pipe is effectively reduced, the instability and the overturning risk of a small-section high frame are avoided, and the investment and the construction difficulty are reduced;
4. the multi-section inner cylinder is ingeniously adopted, the arranged fireproof ceramic fiber cotton layer effectively solves the problem of thermal expansion of the outer cylinder, the cavity and the inner cylinder in contact with ambient air, hot air and smoke caused by different temperatures, the inner cylinder is sealed through self weight of the inner cylinder, and the structure is reasonable. Compared with the traditional expansion joint, the expansion joint can avoid fatigue fracture caused by long-term wind load vibration at the top of the chimney, effectively prevent the hot air and the flue gas from streaming and short-circuiting in advance, and prolong the service life;
5. when the existing device is subjected to white elimination transformation, the CEMS sampling point height can be completely ensured to be consistent with the original installation position, and the sampling port of the outer barrel cavity is arranged, so that hot air can be rechecked without mixing with flue gas in advance, and the environmental protection requirement is met.
Drawings
FIG. 1 is a schematic process flow diagram of an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of an embodiment of the present invention.
Fig. 3 is a sectional view taken along a-a in fig. 2.
Fig. 4 is a sectional view taken along the direction B-B in fig. 2.
FIG. 5 is a schematic diagram of a lower ring plate structure according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of inner barrel splicing in an embodiment of the present invention.
FIG. 7 is a schematic view of a connecting plate according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
As shown in FIGS. 1 to 7, the catalytic cracking apparatus was operated at 220000Nm at 140 ten thousand tons/year3For example, the whitening modification of the/h flue gas denitration dust removal desulfurization device, the catalytic cracking flue gas whitening mixed air heating process of the embodiment includes the following steps:
the temperature of the flue gas sent from the catalytic cracking section is 280 ℃, the pressure is 5.5KPaG, the flue gas is firstly sent into a flue gas heat exchanger 01 to exchange heat with boiler water, waste heat recovery is carried out, and the flue gas after heat exchange is sent into an existing arbitrary washing tower 3 to be desulfurized and dedusted at 194 ℃. The boiler water with the temperature of 102 ℃ is firstly sent into a pressure-stabilizing buffer tank 04, the pressure is maintained at 2.0MPaG by medium-pressure nitrogen, the boiler water from the pressure-stabilizing buffer tank 04 is sent into a boiler water circulating system, the boiler water is pressurized by a boiler water circulating pump 06, then sent into a flue gas heat exchanger 01 for heat extraction and temperature rise to 185 ℃, then sent to an air heater 05 for heating the normal-temperature air sent by a fan 07, and the boiler water releases heat, is cooled to 150 ℃ and then returns to the boiler water circulating pump 06. The hot air temperature at the outlet of the air heater 05 is 140 ℃, and the hot air and the purified flue gas at the temperature of 45.9 ℃ after the desulfurization and the dust removal are mixed and superheated to 80 ℃ in a chimney 02, and then the mixture is discharged to the atmosphere, so that the condition that no white smoke exists at the temperature of 10 ℃ in winter is ensured.
In this embodiment, the boiler water circulation pump 06 provides 21 meters of lift to overcome piping and equipment drag drops.
Boiler water in the flue gas heat exchanger 01 flows through the tube side, flue gas flows through the shell side, and the tube bundle is connected in series in 2 grades, each grade can be cut out alone, and a boiler water inlet and a boiler water outlet are independently arranged. A first bypass 08 and a second bypass 010 are arranged on the boiler water pipe side and the flue gas side to adjust and control the temperature of boiler water and avoid vaporization of boiler water caused by overhigh temperature.
The boiler water side pipeline of the air heater 05 is provided with a rapid heating bypass 09 to ensure that the boiler water temperature is lower than the rapid body temperature when the acid dew point temperature when the device is started, and avoid dew point corrosion.
The chimney 02 of the present embodiment includes:
the outer cylinder comprises an upper section 1 of the outer cylinder and a lower section 2 of the outer cylinder which are mutually connected from top to bottom, wherein the upper section 1 of the outer cylinder is a circular cylinder, the lower section 2 of the outer cylinder is a conical reducing section with gradually increasing inner diameter from top to bottom, and a hot air mixing inlet 12 is arranged on the lower section 2 of the outer cylinder;
the inner cylinder is sleeved in the outer cylinder and comprises an upper inner cylinder section 4, a middle inner cylinder section 5 and a lower inner cylinder section 6 which are mutually connected from top to bottom, the upper inner cylinder section 4 and the middle inner cylinder section 5 are circular cylinders, the lower inner cylinder section 6 is a conical reducing section with the inner diameter gradually increasing from top to bottom, and the lower inner cylinder section 6 is positioned at the lower part of the lower outer cylinder section 2;
the diameter of the inner cylinder is smaller than that of the outer cylinder, a cavity 100 for the circulation of preheated air is formed between the inner cylinder and the outer cylinder, and a channel for the circulation of flue gas for the desulfurization and dust removal of the washing tower is formed in the inner space of the inner cylinder.
The cross-sectional area of the cavity is 1 to 1.5 times of the sum of the cross-sectional areas of the hot air mixing openings on the outer cylinder.
The height of the lower section 6 of the inner cylinder is lower than that of the lower section 2 of the outer cylinder, and the diameter-changing gradient of the lower section 6 of the inner cylinder is greater than that of the lower section 2 of the outer cylinder.
The top of the cavity 100 is provided with a top ring plate 7, one side of the top ring plate 7 is welded with the inner wall surface of the outer cylinder upper section 1 of the outer cylinder, the other side of the top ring plate 7 is welded with the top surface of the inner cylinder upper section 4 of the inner cylinder, and the top end of the inner cylinder upper section 4 of the inner cylinder is provided with four square holes 17.
The bottom end of the inner cylinder lower section 6 of the inner cylinder is provided with a bottom ring plate 8, one side of the bottom ring plate 8 is welded with the inner wall surface of the washing tower cylinder section 3, the other side of the bottom ring plate 8 is welded with the bottom end of the inner cylinder lower section 6 of the inner cylinder, and twenty inner cylinder reinforcing rib plates 9 used for supporting the inner cylinder are further arranged below the bottom ring plate 8.
The lower part of the upper section 4 of the inner cylinder is provided with a plurality of first sampling ports 11, the first sampling ports comprise CEMS sampling ports and/or manual sampling ports, and the first sampling ports 11 penetrate through the cavity 100 and are only directly communicated with the inner cylinder.
The first sampling port 11 is positioned below the square hole 17 of the upper section 4 of the inner cylinder, and the distance from the first sampling port 11 to the lower section 6 of the inner cylinder is 4 times of the diameter of the inner cylinder, and the distance from the first sampling port 11 to the lower edge of the square hole 17 of the upper section 4 of the inner cylinder is 2 times of the diameter of the inner cylinder.
The middle part of the upper section 1 of the outer barrel is provided with a second manual sampling port 10, and the second manual sampling port 10 is only connected with the cavity 100.
An inspection manhole 15 is further arranged on the lower section 2 of the outer barrel at the lower part of the outer barrel, and symmetrically distributed inspection drainage condensation ports 16 are arranged on the bottom annular plate 8 at the bottom of the cavity 100.
A refractory ceramic fiber cotton layer 18 with the same thickness as the inner cylinder is arranged between the inner cylinder upper section 4 and the inner cylinder middle section 5 of the inner cylinder, an inner ring plate 20 and an outer ring plate 19 are arranged on two sides of the fiber cotton layer, and the bottom surfaces of the lower parts of the inner ring plate 20 and the outer ring plate 19 are welded and fixed with the inner wall surface and the outer wall surface of the inner cylinder middle section 5 of the inner cylinder. To facilitate the mounting of the inner barrel upper section 4, the upper end of the inner annular plate 20 is bent inwardly at a small angle and similarly the upper end of the outer annular plate 19 is bent outwardly at a small angle.
In order to better support the inner cylinder, six connecting plates 14 are further arranged on the upper section 4 of the inner cylinder, and the connecting plates 14 penetrate through the inner cylinder and the outer cylinder and are welded and sealed with the inner cylinder and the outer cylinder. The inner side of the inner cylinder is provided with reinforcing ribs 13 from top to bottom.
When the device is used, flue gas which is desulfurized and dedusted from any existing washing tower enters a chimney and inner barrel channel from the conical reducing section of the lower section 6 of the inner barrel of the chimney in the embodiment, preheated hot air enters a chimney and cavity 100 channel from the hot air mixing port of the conical reducing section with the gradually increased inner diameter from top to bottom of the lower section 2 of the outer barrel, two streams of gas are completely isolated, and the hot air is mixed with the flue gas through the square hole 17 at the top of the inner barrel, so that the flue gas is exhausted from the top of the chimney after being overheated.
Directional terms such as "front," "rear," "upper," "lower," "left," "right," "side," "top," "bottom," and the like are used in the description and claims of the present invention to describe various example structural portions and elements of the invention, but are used herein for convenience of description only and are to be determined based on the example orientations shown in the drawings. Because the disclosed embodiments of the present invention may be oriented in different directions, the directional terms are used for descriptive purposes and are not to be construed as limiting, e.g., "upper" and "lower" are not necessarily limited to directions opposite to or coincident with the direction of gravity.

Claims (10)

1. A catalytic cracking flue gas white-eliminating mixed air heating process is characterized by comprising the following steps:
the temperature of the flue gas sent from the catalytic cracking section is 180-;
the flue gas after heat exchange is carried out at the temperature of 150 ℃ and 220 ℃, and is sent into the existing arbitrary washing tower (3) for desulfurization and dust removal;
boiler water with the temperature of 100-200 ℃ is firstly sent into a pressure stabilizing buffer tank (04), the pressure is maintained at 1.5-2.5 MPaG by medium-pressure nitrogen, the boiler water from the pressure stabilizing buffer tank (04) is sent into a boiler water circulating system, is pressurized by a boiler water circulating pump (06), then is sent into a flue gas heat exchanger (01) for heat extraction, is heated to 160-plus-pressure 200 ℃, then is sent to an air heater (05), and is heated by normal-temperature air sent by a fan (07); the boiler water releases heat and is cooled to 150-160 ℃ and then returns to the boiler water circulating pump (06) for circulation;
the temperature of hot air at the outlet of the air heater (05) is 100-150 ℃, and the hot air and the purified flue gas at the temperature of 45-60 ℃ after the desulfurization and the dust removal are mixed and superheated to 70-90 ℃ in a chimney (02) and then discharged into the atmosphere.
2. The catalytic cracking flue gas whitening and air mixing heating process according to claim 1, characterized in that: after the boiler water is subjected to heat taking and heat releasing circulation, a 10-25 m lift is provided by a boiler water circulating pump (06) to overcome resistance drop of pipelines and equipment, a pressure stabilizing buffer tank (04) does not participate in boiler water circulation, only system pressure and liquid level are maintained, and additional continuous boiler water supplement is not needed.
3. The catalytic cracking flue gas whitening and air mixing heating process according to claim 1, characterized in that: boiler water walks the pipe side in gas heater (01), and the shell side is walked to the flue gas, and the tube bank of gas heater (01) is 2 grades and establishes ties, and every grade can be surely alone cut to independently set up boiler water and import and export.
4. The catalytic cracking flue gas whitening and air mixing heating process according to claim 3, characterized in that: and a bypass for adjusting and controlling the temperature of boiler water so as to avoid the vaporization of the boiler water caused by overhigh temperature is arranged on the boiler water pipe side and the flue gas side.
5. The catalytic cracking flue gas whitening and air mixing heating process according to claim 1, characterized in that: the boiler water side pipeline of the air heater (05) is provided with a rapid temperature rise bypass (09) for ensuring that the temperature of the boiler water is lower than the temperature of the acid dew point when the device is driven so as to avoid dew point corrosion.
6. The catalytic cracking flue gas air-white mixing heating process according to any one of claims 1 to 5, wherein the chimney comprises:
the outer cylinder comprises an upper outer cylinder section (1) and a lower outer cylinder section (2) which are mutually connected from top to bottom, the upper outer cylinder section (1) is a circular cylinder, the lower outer cylinder section (2) is a conical reducing section with the inner diameter gradually increasing from top to bottom, and a hot air mixing inlet (12) is formed in the lower outer cylinder section (2);
the inner cylinder is sleeved in the outer cylinder and comprises an upper inner cylinder section (4), a middle inner cylinder section (5) and a lower inner cylinder section (6) which are mutually connected from top to bottom, the upper inner cylinder section (4) and the middle inner cylinder section (5) are circular cylinders, the lower inner cylinder section (6) is a conical reducing section with the inner diameter gradually increasing from top to bottom, and the lower inner cylinder section (6) is positioned at the lower part of the lower outer cylinder section (2);
the diameter of the inner cylinder is smaller than that of the outer cylinder, a cavity (100) for preheating air circulation is formed between the inner cylinder and the outer cylinder, and a channel for flue gas circulation of the washing tower for completing desulfurization and dust removal is formed in the inner space of the inner cylinder.
7. The catalytic cracking flue gas whitening and air mixing heating process according to claim 6, characterized in that: the sectional area of the cavity is 1 to 1.5 times of the sum of the sectional areas of the hot air mixing openings on the outer cylinder; the height of the inner cylinder lower section (6) of the inner cylinder is lower than that of the outer cylinder lower section (2) of the outer cylinder, and the diameter-changing gradient of the inner cylinder lower section (6) is greater than or equal to that of the outer cylinder lower section (2).
8. The catalytic cracking flue gas white-eliminating mixed air heating process according to claim 6, characterized in that: a top ring plate (7) is arranged at the top of the cavity (100), one side of the top ring plate (7) is welded with the inner wall surface of the outer cylinder upper section (1) of the outer cylinder, the other side of the top ring plate (7) is welded with the top surface of the inner cylinder upper section (4) of the inner cylinder, and a square hole (17) is formed in the top end of the inner cylinder upper section (4) of the inner cylinder; a bottom ring plate (8) is arranged at the bottom end of the lower section (6) of the inner cylinder, one side of the bottom ring plate (8) is welded with the inner wall surface of the washing tower cylinder section (3), the other side of the bottom ring plate (8) is welded with the bottom end of the lower section (6) of the inner cylinder, and an inner cylinder reinforcing rib plate (9) for supporting the inner cylinder is arranged below the bottom ring plate (8); the lower part of the upper section (4) of the inner cylinder is provided with a plurality of first sampling ports (11), the first sampling ports comprise CEMS sampling ports and/or manual sampling ports, and the first sampling ports (11) penetrate through the cavity (100) and are only directly communicated with the inner cylinder.
9. The catalytic cracking flue gas whitening and air mixing heating process according to claim 8, characterized in that: the first sampling port (11) is positioned below a square hole (17) of the upper section (4) of the inner cylinder, the distance from the first sampling port (11) to the lower section (6) of the inner cylinder is 4 times of the diameter of the inner cylinder, and the distance from the first sampling port to the lower edge of the square hole (17) of the upper section (4) of the inner cylinder is 2 times of the diameter of the inner cylinder; the middle part of the outer barrel upper section (1) of the outer barrel is provided with a second manual sampling port (10), and the second manual sampling port (10) is only connected with the cavity (100).
10. The catalytic cracking flue gas white-eliminating mixed air heating process according to claim 6, characterized in that: an inspection manhole (15) is further arranged on the lower section (2) of the outer barrel at the lower part of the outer barrel, and inspection drainage condensation ports (16) which are symmetrically distributed are arranged on a bottom annular plate (8) at the bottom of the cavity (100); a refractory ceramic fiber cotton layer (18) with the same thickness as the inner cylinder is arranged between the inner cylinder upper section (4) and the inner cylinder middle section (5) of the inner cylinder, an inner ring plate (20) and an outer ring plate (19) are arranged on two sides of the fiber cotton layer, and the bottom surfaces of the lower parts of the inner ring plate (20) and the outer ring plate (19) are fixedly welded with the inner wall surface and the outer wall surface of the inner cylinder middle section (5) of the inner cylinder.
CN202111681595.8A 2021-12-29 2021-12-29 Air mixing and heating process for eliminating white smoke of catalytic cracking Pending CN114484489A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111681595.8A CN114484489A (en) 2021-12-29 2021-12-29 Air mixing and heating process for eliminating white smoke of catalytic cracking

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111681595.8A CN114484489A (en) 2021-12-29 2021-12-29 Air mixing and heating process for eliminating white smoke of catalytic cracking

Publications (1)

Publication Number Publication Date
CN114484489A true CN114484489A (en) 2022-05-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111681595.8A Pending CN114484489A (en) 2021-12-29 2021-12-29 Air mixing and heating process for eliminating white smoke of catalytic cracking

Country Status (1)

Country Link
CN (1) CN114484489A (en)

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