CN108067050B - High-efficient multistage defroster - Google Patents
High-efficient multistage defroster Download PDFInfo
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- CN108067050B CN108067050B CN201610990960.6A CN201610990960A CN108067050B CN 108067050 B CN108067050 B CN 108067050B CN 201610990960 A CN201610990960 A CN 201610990960A CN 108067050 B CN108067050 B CN 108067050B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/12—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces
- B01D45/16—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces generated by the winding course of the gas stream, the centrifugal forces being generated solely or partly by mechanical means, e.g. fixed swirl vanes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/02—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by utilising gravity
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/04—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by utilising inertia
- B01D45/08—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by utilising inertia by impingement against baffle separators
Abstract
The invention discloses a high-efficiency multistage demister. The demister comprises a plurality of demisting components, each demisting component comprises a gas riser and an outer barrel, the outer barrel is arranged on the outer side of the gas riser and is arranged on the same axis with the gas riser, the gas riser is fixed on a tower tray, an upper sealing cover plate is arranged at the top of the gas riser, a lower sealing cover plate is arranged at the bottom of the gas riser, gas inlet holes are uniformly formed in the circumference of the lower end of the gas riser, a gas inlet guide plate is arranged on the inner wall of the gas riser at the gas inlet holes, and a rectifying channel is arranged on the circumference of the upper. The demister realizes the separation of liquid drops and gas through the rectification, acceleration and scraping effect of fluid in the flowing process. The demister disclosed by the invention is simple in structure, convenient to install, not easy to scale, capable of effectively realizing gas-liquid separation and reducing entrainment, and particularly suitable for occasions with large gas flow fluctuation.
Description
Technical Field
The invention relates to gas-liquid separation equipment, in particular to a high-efficiency multistage demister.
Background
Large amount of SO is generated in the production process of industries such as electric power, metallurgy, petrochemical industry and the like2And dust and other harmful substances, which bring serious acid rain hazard and haze weather, is the air pollutant which is currently controlled in China. At present, the wet desulphurization technology is generally adopted in the field of environmental protection to remove harmful substances such as sulfur dioxide in flue gas, namely, alkali liquor is sprayed on the flue gas to absorb or adsorb the harmful substances. However, in the wet desulfurization process, the flue gas desulfurized by the absorption tower contains a large amount of fine liquid drops with the particle size of about 10-60 microns, and sulfuric acid, sulfate and SO are dissolved in the liquid drops2Etc. not only will cause pollution to the atmospheric environment, but alsoIt also causes serious corrosion and scaling of subsequent equipment. Thus, when using a wet desulfurization process, the cleaned gas must be demisted prior to exiting the absorber tower, and the demisting step is accomplished by means of a demister.
The defroster generally sets up at the absorption tower top, and when the gas that contains the mist passes through the defroster with certain speed, can collide with defroster inner structure to attach on its surface. Mist on the surface of the inner structure of the demister can be gradually gathered under the action of diffusion and gravity, and after the weight reaches a certain level, the mist can be separated from the inner structure of the demister, so that gas-liquid separation is realized. When the demister causes resistance drop to increase to a preset value due to scaling in the operation process, a backwashing program needs to be started to wash the demister, generally, washing nozzles need to be arranged at the air inlet end and the air exhaust end of the demister, and the gas phase can be seriously carried to the liquid phase to cause liquid entrainment of the gas phase.
Common demisters include a wire mesh demister, a herringbone plate demister, a spiral-flow plate demister and the like. Although the wire mesh demister can separate common mist, the mist is required to be clean, the flow velocity of air flow is small, resistance is reduced greatly, the service cycle is short, and the equipment investment is large. The current demister is generally arranged horizontally, the gas flowing direction of the demister is perpendicular to a wire mesh, when the gas velocity is low, entrained mist is small in inertia, the mist waves in the gas and cannot be removed due to collision contact with the wire mesh, and the gas is easy to generate secondary entrainment to the liquid drops due to the fact that separated liquid drops and the gas phase are in a countercurrent flow direction, so that the gas-liquid separation efficiency is reduced, and the wire mesh demister also has the problems of easy blockage, large pressure drop and the like. The blade type and herringbone demister are internally provided with baffle plates with different directions and different shapes so as to form a small flow channel, increase the demisting effect, and have more complex structure and poor separation effect. The whirl plate defroster is the same with the gaseous flow direction by the separation liquid drop, easily produces the secondary and smugglies secretly, reduces defogging efficiency to the pressure drop is big, and the energy consumption is higher.
The demisting element introduced in CN200410014713.X consists of a baffle plate and a flue gas flow field adjusting block, wherein the baffle plate is fixed on the flue gas flow field adjusting block, and the density and the shape of the baffle plate are changed according to the change of flow field parameters at each position of a flow section, so that the flow section of airflow in an absorption tower is uniformly distributed, and the phenomenon of gas-liquid countercurrent in the drop falling process can not be avoided, namely secondary entrainment is easy to generate.
The defroster that CN200920128824.1 introduced comprises cooler, thick defroster and smart defroster etc. and thick defroster is wave plate or defogging board, and smart defroster is the wire net, and this defroster has changed the shortcoming that traditional defroster liquid droplet flows against the current with the air current direction, has improved defogging efficiency. But this defroster structure is more complicated, and the preparation is difficult, owing to adopted the wire mesh structure, the defroster pressure drop is great, also blocks up relatively easily.
CN203724892U introduces a straight cylindric baffling formula defroster comprises a plurality of defogging subassembly, and every defogging subassembly all includes gas-lift pipe and urceolus, and the circumference of gas-lift pipe is opened has a plurality of seams, is provided with slot and tangential water conservancy diversion wing on the gas-lift pipe circumference that is close to each seam, and the tangential water conservancy diversion wing plays the water conservancy diversion effect, makes the gas flow direction change. The separation of liquid drops and gas is realized through multiple baffling of fluid in the flowing process, the liquid drops with smaller particle size can be effectively removed, and the demisting efficiency is higher. However, after the gas flows through the tangential flow guide wings, the gas direction is still relatively divergent and not concentrated enough, the gas speed is reduced, and the impact force is smaller when the gas collides with the inner wall of the outer barrel, so that the demisting effect is influenced. This defroster mainly relies on the baffling to make gaseous direction change, thereby gaseous and solid wall bumps and realizes gas-liquid separation, and is better to great liquid drop defogging effect, nevertheless is not obvious to the droplet effect, and this defroster structure is more complicated, and the easy scale deposit in space between gas-lift pipe and the tangential water conservancy diversion wing.
US7618472B2 provides a vane type demister comprised of corrugated plates, flat plates, louvers, etc. and defining a plurality of cavities or channels. After the gas-liquid mixture enters the demister, the fluid flow channel is deviated, so that the flow direction of the fluid can be changed for a plurality of times, the speed change is very fast, and the liquid phase is easily separated from the gas phase. In the process of separating the liquid phase from the gas phase, the gas-liquid cross flow can be realized, so that the secondary entrainment effect of the gas phase on liquid drops is greatly reduced, but the technology has a very complicated structure, high processing difficulty and high corresponding processing and manufacturing cost.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the high-efficiency multistage demister, which realizes the separation of liquid drops and gas through rectification, acceleration and scraping effect of fluid in the flowing process. The demister disclosed by the invention has the advantages of simple structure, small pressure drop, difficulty in scaling and convenience in installation, reduces entrainment and can effectively realize gas-liquid separation.
The efficient multistage demister comprises a plurality of parallel demisting components, each demisting component comprises a gas lift pipe and an outer cylinder, and the outer cylinder is arranged on the outer side of the gas lift pipe and preferably on the same axis with the gas lift pipe; the gas lift pipe is fixed on the tower tray, the bottom of the gas lift pipe is lower than the tower tray by a certain distance, the top of the gas lift pipe is provided with an upper sealing cover plate, and the bottom of the gas lift pipe is provided with a lower sealing cover plate; a plurality of rectifying channels are uniformly arranged on the circumference of the riser above the tower tray, the rectifying channels are horizontally embedded along the tangential direction of the outer wall of the riser, the side wall I of one side, close to the outer cylinder, of each rectifying channel is tangent to the wall of the riser, the other side wall II of the rectifying channel is intersected with the wall of the riser, and the rotating directions of the rectifying channels are the same; the top of the rectification channel is flush with the upper cover plate, and the bottom of the rectification channel is intersected with the tube wall of the gas lift tube; a plurality of air inlet holes are uniformly arranged on the circumference of the air lifting pipe below the tower tray, and an air inlet guide plate is arranged on the inner wall of the air lifting pipe at the air inlet holes.
In the demister, the air inlet guide plate is arranged at the edge of the air inlet along the axial direction of the air lifting pipe and is fixedly connected with the inner wall of the air lifting pipe, and the included angle between the tangent plane of the outer wall of the air lifting pipe, which is made by the connecting line of the middle points of the upper and lower curves of the intersecting line of the air inlet and the outer wall of the air lifting pipe, and the plane of the air inlet guide plate close to one side of the air inlet is gamma which is 10-60 degrees, preferably 20-35 degrees.
In the demister of the invention, the number of the rectifying channels is generally 1-12, preferably 4-8. The wall thickness of the rectifying channel is preferably the same as the wall thickness of the riser.
In the demister, the length l of the rectifying channel is the length of the side wall II, the width w is the maximum horizontal distance between the two side walls of the rectifying channel, and the height h is the maximum vertical distance between the top and the bottom of the rectifying channel; wherein the length l is 2-5 times, preferably 3-4 times of the width w; the cross section of the rectifying channel is in one or more combinations of rectangle, ellipse, circle, trapezoid or semicircle, and preferably in one or more combinations of rectangle, ellipse or circle. The size of the rectifying channel is determined by a person skilled in the art according to actual working conditions or design requirements, and if the height h of the rectifying channel is generally 20-600 mm, preferably 100-300 mm; the width w of the rectifying channel is generally 10-200 mm, preferably 20-100 mm. The total cross section area of the rectification channel is 0.2-0.9 times of the cross section area of the gas lift pipe, and preferably 0.3-0.6 times of the cross section area of the gas lift pipe.
In the demister, the tail end of the side wall II of the rectifying channel can be flush with the inner wall of the gas lift pipe or extend into the gas lift pipe for a certain distance m, wherein m is 0.1-0.9 times of the length l, and preferably 0.3-0.6 times. When the tail end of the side wall II of the rectifying channel is flush with the inner wall of the gas lift pipe, the tail end of the bottom of the rectifying channel is also flush with the inner wall of the gas lift pipe; when the side wall II of the rectifying channel extends into the interior of the gas lift pipe for a certain distance m, the tail end of the bottom of the rectifying channel is flush with the tail end of the side wall.
In the demister, the bottom of the rectifying channel is away from the tower tray by a certain distance A, and the distance A is 20-200 mm, preferably 40-80 mm.
In the demister, the number of the air inlet holes is generally 3-12, preferably 4-8. The cross section of the air inlet hole is in one or more combinations of rectangle, ellipse, circle, trapezoid or semicircle, and preferably in one or more combinations of rectangle, ellipse or circle. The total sectional area of the air inlet holes is 0.6-1.5 times, preferably 0.8-1.2 times of that of the air lifting pipe, and the specific size is determined by a person skilled in the art according to the actual working condition or design requirement.
In the demister, the rotating direction of each air inlet guide plate is the same as that of the rectifying channel, the shape of each air inlet guide plate can be one or a combination of more of rectangle, ellipse, circle, trapezoid or semicircle, and the like, the shape of each air inlet guide plate is preferably the same as that of an air inlet hole, and the area of each air inlet guide plate is 1.1-2 times, preferably 1.3-1.5 times that of the air inlet hole.
In the demister, the lower sealing cover plate (the bottom of the riser) has a certain distance K from the tower tray, and the distance K is 60-200 mm, preferably 80-120 mm.
In the demister, the riser is hermetically connected with the tower tray, and the diameter of the riser and the aperture ratio of the tower tray can be determined by a person skilled in the art according to the actual working condition or design requirement.
In the demister, the rectifying channel, the upper cover plate, the lower cover plate and the gas rising pipe can be welded together or integrally formed.
In the demister of the invention, the outer cylinder is a cylinder, and the diameter D of the outer cylinder is 1.5 to 6 times, preferably 2 to 3 times of the diameter D of the draft tube. The upper edge of the outer cylinder is higher than the upper edge of the gas lift pipe by a certain distance P, and the distance P is 1-8 times, preferably 2-5 times, of the height h of the rectifying channel. The lower edge of the outer cylinder is away from the tower tray by a certain distance B and is lower than the lower edge of the rectifying channel, and the distance B between the lower edge of the outer cylinder and the tower tray is 5-100 mm, preferably 20-50 mm. The total height H of the outer barrel is 2.5-10 times, preferably 3-5 times of the height of the rectifying channel.
In the demister of the invention, the inner surface of the outer cylinder is provided with grooves and/or bulges. The protrusions or grooves are parallel to the axis of the outer barrel or may be at an angle to the axis. The cross section of the groove or the bulge can also be in a proper shape such as a rectangle, a triangle or a circle.
In the demister of the invention, the inner surface of the outer cylinder is preferably provided with a groove with a cross section shape as shown in fig. 5, and the cross section of the groove is composed of an arc and a straight line segment; the intersection points of the circular arcs and the circumference of the inner surface of the outer barrel are tangent lines of the circular arcs and the circumference respectively, the included angle between the tangent lines is alpha, the alpha is 5-70 degrees, and preferably 10-40 degrees; the included angle between the tangent of the arc at the intersection point of the arc and the straight line segment is beta, wherein the beta is 30-110 degrees, and preferably 45-90 degrees. The depth Z of the groove, namely the shortest distance from the intersection point of the circular arc and the straight line section to the circumference of the inner surface of the outer cylinder is 0.1-0.7 times of the wall thickness of the outer cylinder, and preferably 0.3-0.5 times; the arc length between the intersection point of the arc and the circumference of the inner surface of the outer cylinder and the intersection point of the straight line segment and the circumference of the inner surface of the outer cylinder is 1/80-1/6 of the circumference of the inner surface of the outer cylinder.
In the demister, the lower end opening of the outer cylinder can be arranged into a zigzag or wavy structure, so that separated liquid is more favorably dripped from the inner wall of the outer cylinder into continuous flow.
The connection parts of the components of the demister are sealed, and the phenomenon of air leakage is avoided.
When the demister works, gas carrying liquid drops enters the riser from the gas inlet hole at the lower end of the tower tray along the horizontal direction, and the gas phase flow direction is changed from the radial direction to the tangential direction after meeting the gas inlet guide plate, so that the gas can flow upwards along the inner wall of the riser in a spiral manner, and the cyclone effect is enhanced. In the process, part of the liquid drops collide with the air inlet guide plate to enable some small liquid drops to be attached and converged on the air inlet guide plate, the attached liquid drops gradually become larger, and when the gravity generated by the part of the larger liquid drops exceeds the resultant force of the rising force of the gas and the surface tension of the liquid, the liquid drops fall along the surface of the air inlet guide plate to be separated, namely, the first gas-liquid separation is completed; the other part of the larger liquid drops continuously flow with the gas and upwards flow along the inner wall disc of the riser in a rotating way. When the gas carrying the liquid drops rises in the gas rising pipe, the gas phase flow direction is changed after the gas meets the upper cover plate, and part of the liquid drops collide with the upper cover plate, so that secondary gas-liquid separation is completed; meanwhile, part of the small liquid drops are gathered into larger liquid drops and continue to flow along with the gas. The gas carrying the liquid drops enters the rectifying channel along the horizontal direction or the approximate horizontal direction, because the rectifying channel has a certain length, and the total sectional area of the rectifying channel is smaller than the sectional area of the riser, the original gas carrying the liquid drops with a relatively dispersed speed direction is changed into the direction along the rectifying channel after entering the rectifying channel, the speed direction is relatively regular and concentrated, and because the flow area is reduced, the speed of the gas carrying the liquid drops is increased after entering the rectifying channel. When the speed direction of the gas carrying the liquid drops is changed, part of the liquid drops collide with the inner wall of the rectifying channel and are attached to the inner wall of the rectifying channel, and then the gas flowing through the rectifying channel continuously blows out of the rectifying channel and falls down to complete third gas-liquid separation. Meanwhile, in the rectifying channel, because the speed and direction of the gas carrying the liquid drops are changed, part of the small liquid drops collide with each other under the action of inertia force, the small liquid drops are gathered into large liquid drops, and the speed of the gas carrying the liquid drops flowing through the rectifying channel is increased, so that the movement of the liquid drops is intensified, the probability of the mutual collision of the small liquid drops is improved, the small liquid drops are more easily gathered into the large liquid drops and flow out of the rectifying channel along with the gas at a higher speed. The gas which flows out from the rectifying channel and is carried with the liquid drops has higher speed, the speed direction is more concentrated, the carried liquid drops are larger, the gas continuously collides with the inner wall of the outer barrel, and the flowing direction of the gas is changed again, namely the gas carried with the liquid drops flows along the circumferential direction of the inner wall of the outer barrel instead of the rectifying channel. Because the gas carrying with the liquid drops has higher speed and flows upwards along the inner wall of the outer cylinder provided with the groove in a rotating way, a relatively obvious scraping effect can be generated. The scraping effect means that when high-speed gas carrying liquid drops flows upwards along the inner wall of the outer barrel in a rotating mode, the liquid drops are thrown to the outer edge continuously under the action of inertia force, the liquid drops enter the groove and move along the arc section in the groove, the liquid drops can continuously move smoothly along the arc surface of the groove due to the included angle alpha of 5-70 degrees, contact gathering and enlargement among the liquid drops are achieved until the straight line section is obstructed, the gathered and enlarged liquid drops are strongly collided with the wall surface of the straight line section and attached to the straight line section of the groove in the inner wall of the outer barrel, the liquid drops are gathered and enlarged continuously, and then the liquid drops flow downwards along the inner wall of the outer; and the gas continuously keeps flowing upwards along the inner wall of the outer barrel at a high speed, so that gas-liquid separation is realized for the fourth time, and entrainment is reduced. Through the rectification, acceleration and scraping effect, the liquid drops and the gas are separated in the flowing process of the fluid.
The demister is applied to an absorption tower adopting a wet desulphurization process, and generally the gas velocity entering a gas lift pipe is 3-20m/s, the gas velocity at the outlet of a rectifying channel is 10-40m/s, and the gas velocity at the outlet of the rectifying channel is 1.5-3 times of the gas velocity entering the gas lift pipe.
Compared with the prior art, the demister disclosed by the invention has the following advantages:
1. the lower end of the gas lift pipe is provided with a lower sealing cover plate, the circumferential direction of the lower end of the gas lift pipe is uniformly provided with a plurality of gas inlet holes, and the inner wall of the gas lift pipe at the gas inlet holes is provided with a plurality of gas inlet guide plates, so that after gas enters the gas lift pipe along the horizontal direction, the gas meets the gas inlet guide plates to change the gas phase flow direction from the radial direction to the tangential direction, the gas can flow upwards along the spiral inner wall of the gas lift pipe, and the.
2. The rectifying channel has a certain length, the original speed direction of the gas with dispersed liquid drops is changed into the direction along the rectifying channel after entering the rectifying channel, and the speed direction is regular and concentrated; and the total sectional area of the rectifying channel is smaller than that of the riser, and the velocity of the gas carrying with liquid drops after entering the rectifying channel is increased due to the reduction of the flow area. The section of the groove on the inner surface of the cylinder is composed of an arc and a straight line segment, when high-speed gas carrying liquid drops flows upwards along the rotation of the inner wall of the outer cylinder, the liquid drops are thrown outwards continuously under the action of inertia force, the liquid drops enter the groove and move along the arc segment in the groove, and because the included angle alpha is 5-70 degrees, the liquid drops can continuously move smoothly along the arc surface of the groove until the straight line segment is blocked and then flow downwards along the inner wall of the outer cylinder, and no dead zone exists.
3. Through multistage defogging, reach the effect of defogging high-efficiently, the less liquid drop of particle diameter smuggleing secretly in the effective desorption gas, the defogging is efficient, has reduced the harm to the environment, has played the effect of environmental protection.
4. The gas flow is uniform, the flow resistance is small, and the resistance is reduced.
5. Simple structure, convenient manufacture, difficult blockage and scaling and no need of backwashing.
6. The water-saving effect is good, and the water removed from the gas carrying the liquid drops can be recycled, so that the water consumption is reduced.
Drawings
FIG. 1 is a schematic view of a demister of the present invention.
Fig. 2 is a schematic cross-sectional view of an air intake hole and an air intake baffle.
FIG. 3 is a schematic cross-sectional view of a demister with a rectifying channel flush with the inner wall.
FIG. 4 is a schematic cross-sectional view of a demister with a rectifying passage extending into the interior of the riser.
FIG. 5 is a schematic view of a groove having a circular arc and a straight line segment in cross section.
Wherein, 1-tray; 2-a riser; 3-rectifying the channel; 4-outer cylinder; 5, sealing the cover plate; 6-groove; 7-an air intake baffle; 8-air inlet holes; and 9-lower sealing cover plate.
Detailed Description
The demister of the present invention will be described in further detail with reference to the accompanying drawings and examples.
The efficient multistage demister comprises a plurality of parallel demisting components, each demisting component comprises a gas rising pipe 2 and an outer cylinder 4, and the outer cylinder 4 is arranged on the outer side of the gas rising pipe 2 and is preferably on the same axis with the gas rising pipe 2; the gas lift pipe 2 is fixed on the tray 1, the bottom of the gas lift pipe 2 is lower than the tray 1 by a certain distance, the top of the gas lift pipe 2 is provided with an upper sealing cover plate 5, and the bottom is provided with a lower sealing cover plate 9; a plurality of rectifying channels 3 are uniformly arranged on the circumference of the riser 2 above the tray 1, the rectifying channels 3 are horizontally embedded along the tangential direction of the outer wall of the riser 2, the side wall I of one side of the rectifying channel 3 close to the outer cylinder 4 is tangent to the tube wall of the riser 2, the other side wall II is intersected with the tube wall of the riser 2, and the rotating directions of the rectifying channels 3 are the same; the top of the rectifying channel 3 is flush with the upper cover plate 5, and the bottom of the rectifying channel is intersected with the tube wall of the gas lift tube 2; a plurality of air inlet holes 8 are uniformly arranged on the circumference of the air-lift pipe 2 below the tray 1, and an air inlet guide plate 7 is arranged on the inner wall of the air-lift pipe 2 at the air inlet holes 8.
In the demister of the invention, the rectifying channel 3 is generally provided with 1-12, preferably 4-8. The wall thickness of the rectifying channel 3 is preferably the same as the wall thickness of the riser 2.
In the demister, the length l of the rectifying channel 3 is the length of the side wall II, the width w is the maximum horizontal distance between the two side walls of the rectifying channel 3, and the height h is the maximum vertical distance between the top and the bottom of the rectifying channel 3; wherein the length l is 2-5 times, preferably 3-4 times of the width w; the cross section of the rectifying channel 3 is in one or more combinations of rectangle, ellipse, circle, trapezoid or semicircle, and preferably in one or more combinations of rectangle, ellipse or circle. The size of the rectifying channel 3 is determined by a person skilled in the art according to actual working conditions or design requirements, and if the height h of the rectifying channel 3 is generally 20-600 mm, preferably 100-300 mm; the width w of the rectifying channel 3 is generally 10 to 200mm, preferably 20 to 100 mm. The total cross-sectional area of the rectifying channel 3 is 0.2-0.9 times of the cross-sectional area of the gas-lifting tube 2, and preferably 0.3-0.6 times of the cross-sectional area of the gas-lifting tube 2.
In the demister, the tail end of the side wall II of the rectifying channel 3 can be flush with the inner wall of the gas lift pipe 2 or extend into the gas lift pipe 2 for a certain distance m, wherein m is 0.1-0.9 times of the length l, and preferably 0.3-0.6 times. When the tail end of the side wall II of the rectifying channel 3 is flush with the inner wall of the gas lift tube 2, the tail end of the bottom of the rectifying channel 3 is also flush with the inner wall of the gas lift tube 2; when the side wall II of the rectifying channel 3 extends into the interior of the gas lift tube 2 for a certain distance m, the tail end of the bottom of the rectifying channel 3 is flush with the tail end of the side wall.
In the demister, the bottom of the rectifying channel 3 is at a certain distance A from the tower tray 1, and the distance A is 20-200 mm, preferably 40-80 mm.
In the demister, the number of the air inlet holes 8 is generally 3-12, preferably 4-8. The cross section of the air inlet 8 is one or a combination of several of rectangle, ellipse, circle, trapezoid or semicircle, preferably one or a combination of several of rectangle, ellipse or circle. The total sectional area of the air inlet holes 8 is 0.6-1.5 times, preferably 0.8-1.2 times of the sectional area of the draft tube 2, and the specific size is determined by a person skilled in the art according to the actual working condition or design requirement.
In the demister, the air inlet guide plate 7 is axially arranged at the edge of the air inlet hole 8 along the air lifting pipe 2 and is fixedly connected with the inner wall of the air lifting pipe 2, the included angle between the tangent plane of the outer wall of the air lifting pipe 2, which is made by the connecting line of the middle points of the upper and lower curves in the intersecting line of the air inlet hole 8 and the outer wall of the air lifting pipe 2, and the plane of the air inlet guide plate 7 close to one side of the air inlet hole 8 is gamma, wherein the gamma is 10-60 degrees, and preferably 20.
In the demister, the rotating direction of each air inlet guide plate 7 is the same as that of the rectifying channel 3, the shape of each air inlet guide plate 7 can be one or a combination of more of rectangle, ellipse, circle, trapezoid or semicircle, and the like, the shape of each air inlet guide plate 7 is preferably the same as that of the air inlet hole 8, and the area of each air inlet guide plate 7 is 1.1-2 times, preferably 1.3-1.5 times, that of the air inlet hole 8.
In the demister, the lower cover plate 9 (the bottom of the riser 2) has a certain distance K from the tower tray 1, and the distance K is 60-200 mm, preferably 80-120 mm.
In the demister, the riser 2 is hermetically connected with the tray 1, and the diameter of the riser 2 and the aperture ratio of the tray 1 can be determined by a person skilled in the art according to actual working conditions or design requirements.
In the demister of the invention, the rectifying channel 3, the upper cover plate 5 and the lower cover plate 9 can be welded together with the gas rising pipe 2 or integrally formed.
In the demister of the present invention, the outer cylinder 4 is preferably a cylinder, and the diameter D of the outer cylinder 4 is 1.5 to 6 times, preferably 2 to 3 times, the diameter D of the draft tube 2. The upper edge of the outer cylinder 4 is higher than the upper edge of the gas lift pipe 2 by a certain distance P, and the distance P is 1-8 times, preferably 2-5 times, of the height h of the rectifying channel 3. The lower edge of the outer cylinder 4 is away from the tower tray 1 by a certain distance B and is lower than the lower edge of the rectifying channel 3, and the distance B from the lower edge of the outer cylinder 4 to the tower tray 1 is 5-100 mm, preferably 20-50 mm. The total height H of the outer cylinder 4 is 2.5 to 10 times, preferably 3 to 5 times, the height of the rectifying channel 3. The outer cylinder 4 can also be one or a combination of a plurality of conical cylinders, inverted conical cylinders, variable diameter cylinders and the like.
In the demister of the invention, the inner surface of the outer cylinder 4 is provided with grooves 6 and/or protrusions. The projections or recesses 6 are parallel to the axis of the outer barrel 4 or may be at an angle to the axis. The cross section of the groove 6 or the bulge can also be in a suitable shape such as a rectangle, a triangle or a circle.
In the demister of the present invention, the inner surface of the outer cylinder 4 is preferably provided with a groove 6 having a cross-sectional shape as shown in fig. 5, and the cross section of the groove 6 is formed by a circular arc and a straight line; wherein, the intersection points of the circular arc and the circumference of the inner surface of the outer cylinder 4 are respectively tangent lines of the circular arc and the circumference, the included angle between the tangent lines is alpha, the alpha is 5-70 degrees, and preferably 10-40 degrees; the included angle between the tangent of the arc at the intersection point of the arc and the straight line segment is beta, wherein the beta is 30-110 degrees, and preferably 45-90 degrees. The depth Z of the groove 6, namely the shortest distance from the intersection point of the circular arc and the straight line section to the circumference of the inner surface of the outer cylinder 4 is 0.1-0.7 times, preferably 0.3-0.5 times of the wall thickness of the outer cylinder 4; the arc length between the intersection point of the arc and the inner surface circumference of the outer cylinder 4 and the intersection point of the straight line segment and the inner surface circumference of the outer cylinder 4 is 1/80-1/6 of the inner surface circumference of the outer cylinder 4.
In the demister of the invention, the lower end opening of the outer cylinder 4 can be arranged into a zigzag or wave-shaped structure, thereby being more beneficial to the separated liquid to drip from the inner wall of the outer cylinder 4 in a continuous flow.
The connection parts of the components of the demister are sealed, and the phenomenon of air leakage is avoided.
When the demister works, gas carrying liquid drops enters the gas-lift tube 2 from the gas inlet hole 8 at the lower end of the tower tray 1 along the horizontal direction, and the gas phase flow direction is changed from the radial direction to the tangential direction after meeting the gas inlet guide plate 7, so that the gas can flow upwards along the inner wall of the gas-lift tube 2 in a spiral manner, and the cyclone effect is enhanced. In the process, part of the liquid drops collide with the air inlet guide plate 7, so that some small liquid drops are attached to and converged on the air inlet guide plate 7, the attached liquid drops gradually become larger, and when the gravity generated by the part of the larger liquid drops exceeds the resultant force of the rising force of the gas and the surface tension of the liquid, the liquid drops fall along the surface of the air inlet guide plate 7 to be separated, namely, the first gas-liquid separation is completed; the other part of the larger liquid drops continue to flow with the gas and rotate along the inner wall of the gas lift tube 2 to flow upwards. When the gas carrying the liquid drops rises in the gas rising pipe 2, the gas phase flow direction is changed after meeting the upper cover plate 5, and part of the liquid drops collide with the upper cover plate 5, so that the secondary gas-liquid separation is completed; meanwhile, part of the small liquid drops are gathered into larger liquid drops and continue to flow along with the gas. The gas carrying the liquid drops enters the rectifying channel 3 along the horizontal direction or the approximate horizontal direction, because the rectifying channel 3 has a certain length, and the total sectional area of the rectifying channel 3 is smaller than the sectional area of the gas lift tube 2, the original gas carrying the liquid drops with a relatively dispersed speed direction is changed into the direction along the rectifying channel 3 after entering the rectifying channel 3, the speed direction is relatively regular and concentrated, and because the flow area is reduced, the speed of the gas carrying the liquid drops is increased after entering the rectifying channel 3. When the speed direction of the gas carrying the liquid drops is changed, part of the liquid drops collide with the inner wall of the rectifying channel 3 and are attached to the inner wall of the rectifying channel 3, and then the gas flowing through the rectifying channel 3 continuously blows out of the rectifying channel 3 and falls down, so that the third gas-liquid separation is completed. Meanwhile, in the rectifying channel 3, because the speed and direction of the gas carrying the liquid drops are changed, part of the small liquid drops collide with each other under the action of inertia force, the small liquid drops are gathered into large liquid drops, and the speed of the gas carrying the liquid drops flowing through the rectifying channel 3 is increased, so that the movement of the liquid drops is intensified, the probability of the mutual collision of the small liquid drops is improved, the small liquid drops are more easily gathered into large liquid drops, and the large liquid drops flow out of the rectifying channel 3 along with the gas at a higher speed. The gas which flows out from the rectifying channel 3 and is entrained with the liquid drops has higher speed, the speed direction is concentrated, the entrained liquid drops are larger, the gas continuously collides with the inner wall of the outer barrel 4, and the flowing direction of the gas is changed again, namely, the gas which is entrained with the liquid drops is changed from the direction along the rectifying channel 3 to the circumferential direction along the inner wall of the outer barrel 4. Because the gas speed of the entrained liquid drops is higher and the gas flows upwards along the inner wall of the outer cylinder 4 provided with the groove 6 in a rotating way, a relatively obvious scraping effect can be generated. The scraping effect means that when high-speed gas carrying liquid drops flows upwards along the inner wall of the outer barrel 4 in a rotating mode, the liquid drops are thrown to the outer edge continuously under the action of inertia force, the liquid drops enter the groove 6 and move along the arc section in the groove 6, the liquid drops can continuously move smoothly along the arc surface of the groove 6 due to the included angle alpha of 5-70 degrees, contact aggregation among the liquid drops is enlarged until the straight line section is obstructed, the enlarged liquid drops are strongly collided with the wall surface of the straight line section and attached to the straight line section of the groove 6 in the inner wall of the outer barrel 4, the liquid drops are continuously aggregated and enlarged, and then the liquid drops flow downwards along the inner wall of the outer barrel 4; and the gas continuously keeps flowing upwards along the inner wall of the outer cylinder 4 at a high speed, so that gas-liquid separation is realized for the fourth time, and entrainment is reduced. Through the rectification, acceleration and scraping effect, the liquid drops and the gas are separated in the flowing process of the fluid.
Example one
150000Nm for purifying flue gas in certain wet scrubber3The apparent water concentration is 10-15 g/Nm3After demisting by the present invention, the concentration of the apparent water in the exhaust gas<0.5g/Nm3And the demisting efficiency is more than or equal to 95 percent.
Example two
100000Nm for purifying flue gas in wet washing tower3The apparent water concentration is 12-16 g/Nm3After demisting by the present invention, the concentration of the apparent water in the exhaust gas<0.6g/Nm3And the demisting efficiency is more than or equal to 95 percent.
Claims (10)
1. The utility model provides a high-efficient multistage defroster, includes the defogging subassembly that a plurality of parallels, its characterized in that: each defogging component comprises a gas rising pipe and an outer barrel, and the outer barrel is arranged on the outer side of the gas rising pipe; the gas lift pipe is fixed on the tower tray, the bottom of the gas lift pipe is lower than the tower tray by a certain distance, the top of the gas lift pipe is provided with an upper sealing cover plate, and the bottom of the gas lift pipe is provided with a lower sealing cover plate; a plurality of rectifying channels are uniformly arranged on the circumference of the riser above the tower tray, the rectifying channels are horizontally embedded along the tangential direction of the outer wall of the riser, the side wall I of one side, close to the outer cylinder, of each rectifying channel is tangent to the wall of the riser, the other side wall II of the rectifying channel is intersected with the wall of the riser, and the rotating directions of the rectifying channels are the same; the tail end of the side wall II of the rectification channel extends into the interior of the gas lift pipe for a certain distance m; the top of the rectification channel is flush with the upper cover plate, and the bottom of the rectification channel is intersected with the tube wall of the gas lift tube; a plurality of air inlet holes are uniformly formed on the circumference of the air lifting pipe below the tower tray, and an air inlet guide plate is arranged on the inner wall of the air lifting pipe at the air inlet holes; the air inlet guide plate is arranged at the edge of the air inlet hole along the axial direction of the air lift pipe and is fixedly connected with the inner wall of the air lift pipe; the total cross section area of the rectification channel is 0.2-0.9 times of the cross section area of the gas lift pipe; the inner surface of the outer cylinder is provided with a groove, and the section of the groove consists of an arc and a straight line section; wherein the intersection points of the circular arc and the circumference of the inner surface of the outer cylinder are tangent lines of the circular arc and the circumference respectively, the included angle between the tangent lines is alpha, and the alpha is 5-70 degrees; the included angle between the tangent of the arc at the intersection of the arc and the straight line segment is beta, and beta is 30-110 degrees; the depth Z of the groove, namely the shortest distance from the intersection point of the circular arc and the straight line section to the circumference of the inner surface of the outer cylinder is 0.1-0.7 times of the wall thickness of the outer cylinder; the arc length between the intersection point of the arc and the circumference of the inner surface of the outer cylinder and the intersection point of the straight line segment and the circumference of the inner surface of the outer cylinder is 1/80-1/6 of the circumference of the inner surface of the outer cylinder.
2. A demister as set forth in claim 1 wherein: the included angle between the tangent plane of the outer wall of the gas lift pipe, which is made by connecting the midpoints of the upper and lower curves of the intersecting line of the gas inlet hole and the outer wall of the gas lift pipe, and the plane of the gas inlet flow guide plate close to one side of the gas inlet hole is gamma which is 10-60 degrees.
3. A demister as set forth in claim 1 wherein: the rotary direction of the air inlet guide plate is the same as that of the rectifying channel.
4. A demister as set forth in claim 1 wherein: the area of the air inlet guide plate is 1.1-2 times of that of the air inlet hole.
5. A demister as set forth in claim 1 wherein: 1-12 rectifying channels are arranged; the length l of the rectifying channel is the length of the side wall II, the width w is the maximum horizontal distance between the two side walls of the rectifying channel, and the height h is the maximum vertical distance between the top and the bottom of the rectifying channel; wherein the length l is 2-5 times of the width w; the cross section of the rectifying channel is in one or a combination of a plurality of shapes of rectangle, ellipse, circle, trapezoid or semicircle.
6. A demister as set forth in claim 1 wherein: 3-12 air inlets are formed; the cross section of the air inlet hole is in one or a combination of a plurality of shapes of rectangle, ellipse, circle, trapezoid or semicircle.
7. A demister as set forth in claim 1 wherein: the total sectional area of the air inlet holes is 0.6-1.5 times of the sectional area of the air lifting pipe.
8. A demister as set forth in claim 1 wherein: the lower cover plate is away from the tower tray by a certain distance K, and the distance K is 60-200 mm.
9. A demister as set forth in claim 1 wherein: the outer cylinder is a cylinder, and the diameter D of the outer cylinder is 1.5-6 times of the diameter D of the riser; the upper edge of the outer cylinder is higher than the upper edge of the gas rising pipe by a certain distance P, and the distance P is 1-8 times of the height h of the rectifying channel; the lower edge of the outer cylinder is away from the tower tray by a certain distance B and is lower than the lower edge of the rectifying channel, and the distance B from the lower edge of the outer cylinder to the tower tray is 5-100 mm; the total height H of the outer barrel is 2.5-10 times of the height of the rectifying channel.
10. A demister as set forth in claim 1 wherein: the inner surface of the outer cylinder is provided with a bulge.
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| CN201610990960.6A CN108067050B (en) | 2016-11-11 | 2016-11-11 | High-efficient multistage defroster |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7001448B1 (en) * | 2001-06-13 | 2006-02-21 | National Tank Company | System employing a vortex finder tube for separating a liquid component from a gas stream |
| US20120168361A1 (en) * | 2010-06-25 | 2012-07-05 | Abbas Motakef | Cyclone induced sweeping flow separator |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2396883Y (en) * | 1999-11-26 | 2000-09-20 | 南京大学 | Conical cyclone gas distributing machine |
| CN102872655B (en) * | 2012-09-21 | 2014-12-03 | 兰州节能环保工程有限责任公司 | Gas-liquid separating device |
| CN203724892U (en) * | 2013-11-05 | 2014-07-23 | 中国石油化工股份有限公司 | Straight cylindrical baffling demister |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7001448B1 (en) * | 2001-06-13 | 2006-02-21 | National Tank Company | System employing a vortex finder tube for separating a liquid component from a gas stream |
| US20120168361A1 (en) * | 2010-06-25 | 2012-07-05 | Abbas Motakef | Cyclone induced sweeping flow separator |
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