CA1161355A - Large capacity air-powered smokeless flare - Google Patents
Large capacity air-powered smokeless flareInfo
- Publication number
- CA1161355A CA1161355A CA000360813A CA360813A CA1161355A CA 1161355 A CA1161355 A CA 1161355A CA 000360813 A CA000360813 A CA 000360813A CA 360813 A CA360813 A CA 360813A CA 1161355 A CA1161355 A CA 1161355A
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- Prior art keywords
- air
- flow
- conduit
- diameter
- gas
- Prior art date
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
- F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
- F23G7/08—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases using flares, e.g. in stacks
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Incineration Of Waste (AREA)
- Gas Burners (AREA)
Abstract
LARGE CAPACITY AIR-POWERED SMOKELESS FLARE
ABSTRACT OF THE DISCLOSURE
A large capacity air-powered flare for smokeless combustion of very large volumes of vented waste gases, comprises a first inner vertical conduit of diameter D1, for the flow of waste gas, and a second larger coaxial conduit of diameter D2, for the flow of primary com-bustion air, at a selected velocity in the annular space therebetween. Above the top the inner conduit there is a cylindrical obstruction of diameter D3 which is greater than D1, but less than D2. This forces the upwardly flowing gases to be deflected outwardly and upwardly into the second annular space between the obstruction and the outer conduit. The velocity of primary combustion air in the second annular space is at least 50 f.p.s., which serves to thoroughly mix with the inflowing gases so that as they rise through the second annular space they continue flowing above the top of the flare as an annular wall of high velocity gas, air and flame. This high velocity annular flow has large surface area on the outside and inside. Because of the high velocity of flow, secondary air is induced into the outside wall of this column, and also axially downwardly into the interior of this flow, where it moves radially outwardly to intersect the flowing gas and provide additional combustion air.
ABSTRACT OF THE DISCLOSURE
A large capacity air-powered flare for smokeless combustion of very large volumes of vented waste gases, comprises a first inner vertical conduit of diameter D1, for the flow of waste gas, and a second larger coaxial conduit of diameter D2, for the flow of primary com-bustion air, at a selected velocity in the annular space therebetween. Above the top the inner conduit there is a cylindrical obstruction of diameter D3 which is greater than D1, but less than D2. This forces the upwardly flowing gases to be deflected outwardly and upwardly into the second annular space between the obstruction and the outer conduit. The velocity of primary combustion air in the second annular space is at least 50 f.p.s., which serves to thoroughly mix with the inflowing gases so that as they rise through the second annular space they continue flowing above the top of the flare as an annular wall of high velocity gas, air and flame. This high velocity annular flow has large surface area on the outside and inside. Because of the high velocity of flow, secondary air is induced into the outside wall of this column, and also axially downwardly into the interior of this flow, where it moves radially outwardly to intersect the flowing gas and provide additional combustion air.
Description
~;13S5 This invention lies in the field of the smokeless burning of waste gases by means of flares.
Still more particularly, this invention relates to the construction of flares for the burning of very large flows of waste gas, of size 200,000 pounds per hour or greater.
Still more particularly, it concerns an improved ; type of construction for flares to burn large quantities of gas smokelessly with reduced expenditure of energy for pressurization of the primary combustion air.
In the prior art large high-powered flares for the srQokeles~ burning of waste gas have been built, up to the size o ab~ut 100,000 pounds per hour, using the power o pressurized air for smokeless combustion. Such prior art devices were constructed in such a form that the primary combustion air was pre-pressured and pre-mixed with the waste gas in such a way that the total flow was in the form of a solid vertical cylinder of rapid upflowing gas and air, such that there was a large induction of secondary air around the outer periphery of this column of flame and gas.
; Because of the surface area limitation to the flow of induced secondary air into the outer wall of the rising column of gas, and the necessity for the secondary air to penetrate to the center of the column in order to avoid incomplete and smoky com~ustion, there was a practical limit of the order of 100,000 pounds per hour for such flares. Such applications that had larger flows than this would require a duplication of two or , more such flares to handle a total flow capacity, ;i3SS
By the present invention it is now possible to provide combustion of 200,000 pounds per hour in a single flare, or less with reduced expenditure of electrical energy for pressurizing the primary combustion air.
However, there is another serious problem in the smokeless combustion of hydrocarbons where the hydrogen to carbon ratio ~H/C-R) is low. Venting~ from an ethylene facility (principally olefinic, or unsaturated compounds) provides gases for smokeless flare burning where the H/C
weight ratio can be as low as 0.166, and difficulty with smoky burning increases as the H/C ratio decreases. For example, consider methane (H/C = .3331 makes no smoke as it burns at the flare; ethane (H/C = .25) makes fa~nt trailing smoke, and propane (H/C =.222) smokes relatively heavily. Smoke density increases as the H/C falls below .222, and difficulty in smoke suppression wi~l vary as the potential smoke density increases. Thus, as the H/C-R decreases, means must be provided to increase the rate of induction of secondary air to provide smokeless combustion. With this invention it is possible to 1are burn without smoke, large flows of waste gases, which are combustible, and which have H/C-~ in the range of 0.333 down to 0.083 (acetylene).
It is the primary object of this invention to provide a smokeless combustion of flare-vented gases for the burning of large flows of waste gases with a minimum expenditure of electrical power for pressurizing the primary combustion air.
116~3SS
It is a further object of this invention to provide a flare for the smokeless combustion of waste gases where total flows of combustible gases can be handled which are considerably greater than the maximum flow possible with prior art equipment, and with reduced expenditure of energy for air pressurization.
It is a still further object to provide a flare for the burning of hydrocarbons having hydrogen to carbon ratios less than about 0.2, with-out smoking.
These and other objects are realized and the limitations of the prior art are overcome in this invention by providing a flare for smokeless combùstion of vented waste gases, comprising:
(a) an inner vertical conduit of diameter Dl, for the upward flow of waste gases for burning;
(b~ an outer vertical conduit of diameter D2 larger than Dl, substan-tially coaxial with said first conduit, forming a substantially enclosed chamber thereabout open at the top and having a first annular passage bétween the two conduits, and connected at the bottom with an air mover means through which primary combustion air is forced at greater than atmospheric pressure by said air mover means;
(c) closed cylindrical obstacle means having an upwardly curved bottom, said obstacle of diameter D3A greater than Dl, but less than D2, supported axially above the top of said inner cylinder by a selected dis-tance, and forming a second annular passage between said obstacle means and said outer conduit;
whereby said waste gas is deflected by said curved bottom radial-ly upwardly and outwardly to intersect and mix with the rising column of primary combustion air flowing in said second annular passage;
(d) means to flow said primary air into said first annular passage sufficient to cause velocity flow of said air in said second annular .30 passage of at least 50 feet per second; and ,~. ~
(e) means to ignite said mixture of gas and air at the top of said second passage.
A better understanding of the principles and details of the in-vention will be obtained from the following description taken in conjunc-tion with the appended drawings in which:
FIGURE 1 is a vertical section of one embodiment of this invention.
FIGURES 2 and 3 are cross-sectional views taken respectively across the planes 2-2 and 3-3 of FIGURE 1.
FIGURES 4 and 5 show plan and cross-sectional views of a modi-fication of FIGURE 1.
FIGURES 6 and 7 show details of the modification of FIGURES 4 and 5 Referring now to the drawings and, in particular, to PIGURE 1, ther~ is shown one embodimcnt of this invention illustrated in cross-section, indicated generally by the numeral 10 The waste gases flow from their source, through the conduit 11 and up to the conduit 12 in accordance with arrows 14. Conduit 12 is of diameter Dl.
There is a second larger, outer conduit 16 of diameter D2, which is closed at the bottom around the inner conduit 12, into which primary combustion air is flowed under selected pressure by means of blower 17, in accordance with arrow 19. The air flow from the blower flows into the bottom of the annular space 18, between the inner and outer conduits. The annular space 18 between the inner 12, and outer 16, conduits is designated as the first annular space The air flow 19 from the blower 17 may enter the space 18, axially or radially, in which case it will flow vertically in the first annular space in accordance with arrows 20. Alternatively, the blower can be mount-ed tangentially to the conduit 16, in which case the air will flow upwardly in the form of a helix in accordance with arrow l9A The helical flow adds turbulence, which assists in the mixing of air and gas.
The second conduit 16 may be reduced in diameter above the point 23 to the diameter of 24, for the purpose of increasing the velocity of the upward flow of air in the space 25. The diameter of this reduced conduit 24 is designated D2A.
Above the top of the inner conduit 12 there is a closed cylindrical object or obstacle 34, which has a curved bottom surface and a curved top surface. It is supported by pipe 38, which is supported by spacers 40, in-: side of, and coaxial with the inner conduit 12. There is a vertical gap between the top of the conduit 12 and the obstacle 34 for the outflow of gases in accordance with arrows lS. The obstacle is of outer diameter D3A.
It is preferred that the top 36 of the obstacle 34 be above the top of the conduit Z4.
A shroud 26 of outer ~iameter D3 substantially, not necessarilydimensionally, eq~al to D3A of the obstacle 34 is fastened to the outer surface of the conduit 12 and the space between the conduit 12 and i 35S
the shroud 26 is filled with a refractory material 30.
This may be a castable material, not necessarily refractory, since the temperature at this point does not warrant refractory material. The top surface of the refractory material defines a conical passage 32 leading from the inside of the conduit 12, out into the second annular space 25 at a point substantially at the vena contracta of the air flow between the obstacle 34 and the top portion of the outer conduit 16. The approximate vena contracta is shown by dotted line. This second annular space is of selected inner and outer diameter, such that under the rapid flow of the primary combustion air 20, mixing with the out-wardly flowing gases 15, there will be a rising annular column 44 of gas and air substantially vertically from the second annular space in accordance with arrows 42. Means such as 48 are provided for igniting the gas. Therefore, there will be flame and hot air and gas rising above the top of the flare.
The purpose of the shroud 26 is to decrease the radial width of the second annular space 25 to in-crease the flow velocity of primary air 42 prior to - mixing with the gas flow 15.
The preferred value of the ratio D2/Dl is approximately 1-7. It can be larger or smaller depend-ing on the desired flow velocity of the gas-air mixture in the second annular passage. The preferred value of flow velocity is 75 ft./sec., but can be as high as 200 ft./sec. or more, or as low as 50 ft./sec., depending on the composition of the waste gas and its hydrogen to carbon ratio.
; _ 6 _ Because of the high velocity of the rising air/
gas mixture 44, secondary combustion air will be induced radially inwardly and outwardly, in accordance with arrows 46 into the outer surface 50 of this annular column 44. Also, there will be a reduced pressure directly above the obstacle 34, which will cause a downflow of atmospheric air 54, which will then be deflected outwardly into the inner surface 52 of this annular wall of gas. Because of the relatively large diameter of the obstacle 34 and the outer conduit 24 there will be a very large surface area for contact and mixing between the induced secondary air 46 and the rising column 44. Also, there will be a large contact area of the inner sur-face 5Z, which will likewise be receiving and mixing with the induced secondary air 54.
Because of the relatively narrow radial dimension of the annular column the penetration depth required of the atmospheric air in order to contact the entire volume of gas in the annular wall will be very much less than that required when the rising column of gas is in the form of a solid cylinder. Consequently, the efficiency of induction and contact of secondary air with the rising column of gas and primary air, : will make this embodiment very efficient in the smoke-less combustion of very large flows of waste gases, without substantial increase in the amount of electrical energy required to provide the pressurized primary air.
Because of this greater efficiency of mixing of the primary air with the waste gases and the more efficient induction and mixing of secondary air, the embodiment shown in FIGURE 1 is more efficient than the prior art devices and, therefore, can handle much larger flows of gas with the same amount of energy required for pressurizing the primary air.
Experience shows that primary air flow in the quantity of about eight to ten percent of the total stoichiometric flow is adequate to provide smokeless combustion of very large flows of gas.
Referring now to PIGURES 2 and 3, there are shown two views in cross-section taken acro~s the planes
Still more particularly, this invention relates to the construction of flares for the burning of very large flows of waste gas, of size 200,000 pounds per hour or greater.
Still more particularly, it concerns an improved ; type of construction for flares to burn large quantities of gas smokelessly with reduced expenditure of energy for pressurization of the primary combustion air.
In the prior art large high-powered flares for the srQokeles~ burning of waste gas have been built, up to the size o ab~ut 100,000 pounds per hour, using the power o pressurized air for smokeless combustion. Such prior art devices were constructed in such a form that the primary combustion air was pre-pressured and pre-mixed with the waste gas in such a way that the total flow was in the form of a solid vertical cylinder of rapid upflowing gas and air, such that there was a large induction of secondary air around the outer periphery of this column of flame and gas.
; Because of the surface area limitation to the flow of induced secondary air into the outer wall of the rising column of gas, and the necessity for the secondary air to penetrate to the center of the column in order to avoid incomplete and smoky com~ustion, there was a practical limit of the order of 100,000 pounds per hour for such flares. Such applications that had larger flows than this would require a duplication of two or , more such flares to handle a total flow capacity, ;i3SS
By the present invention it is now possible to provide combustion of 200,000 pounds per hour in a single flare, or less with reduced expenditure of electrical energy for pressurizing the primary combustion air.
However, there is another serious problem in the smokeless combustion of hydrocarbons where the hydrogen to carbon ratio ~H/C-R) is low. Venting~ from an ethylene facility (principally olefinic, or unsaturated compounds) provides gases for smokeless flare burning where the H/C
weight ratio can be as low as 0.166, and difficulty with smoky burning increases as the H/C ratio decreases. For example, consider methane (H/C = .3331 makes no smoke as it burns at the flare; ethane (H/C = .25) makes fa~nt trailing smoke, and propane (H/C =.222) smokes relatively heavily. Smoke density increases as the H/C falls below .222, and difficulty in smoke suppression wi~l vary as the potential smoke density increases. Thus, as the H/C-R decreases, means must be provided to increase the rate of induction of secondary air to provide smokeless combustion. With this invention it is possible to 1are burn without smoke, large flows of waste gases, which are combustible, and which have H/C-~ in the range of 0.333 down to 0.083 (acetylene).
It is the primary object of this invention to provide a smokeless combustion of flare-vented gases for the burning of large flows of waste gases with a minimum expenditure of electrical power for pressurizing the primary combustion air.
116~3SS
It is a further object of this invention to provide a flare for the smokeless combustion of waste gases where total flows of combustible gases can be handled which are considerably greater than the maximum flow possible with prior art equipment, and with reduced expenditure of energy for air pressurization.
It is a still further object to provide a flare for the burning of hydrocarbons having hydrogen to carbon ratios less than about 0.2, with-out smoking.
These and other objects are realized and the limitations of the prior art are overcome in this invention by providing a flare for smokeless combùstion of vented waste gases, comprising:
(a) an inner vertical conduit of diameter Dl, for the upward flow of waste gases for burning;
(b~ an outer vertical conduit of diameter D2 larger than Dl, substan-tially coaxial with said first conduit, forming a substantially enclosed chamber thereabout open at the top and having a first annular passage bétween the two conduits, and connected at the bottom with an air mover means through which primary combustion air is forced at greater than atmospheric pressure by said air mover means;
(c) closed cylindrical obstacle means having an upwardly curved bottom, said obstacle of diameter D3A greater than Dl, but less than D2, supported axially above the top of said inner cylinder by a selected dis-tance, and forming a second annular passage between said obstacle means and said outer conduit;
whereby said waste gas is deflected by said curved bottom radial-ly upwardly and outwardly to intersect and mix with the rising column of primary combustion air flowing in said second annular passage;
(d) means to flow said primary air into said first annular passage sufficient to cause velocity flow of said air in said second annular .30 passage of at least 50 feet per second; and ,~. ~
(e) means to ignite said mixture of gas and air at the top of said second passage.
A better understanding of the principles and details of the in-vention will be obtained from the following description taken in conjunc-tion with the appended drawings in which:
FIGURE 1 is a vertical section of one embodiment of this invention.
FIGURES 2 and 3 are cross-sectional views taken respectively across the planes 2-2 and 3-3 of FIGURE 1.
FIGURES 4 and 5 show plan and cross-sectional views of a modi-fication of FIGURE 1.
FIGURES 6 and 7 show details of the modification of FIGURES 4 and 5 Referring now to the drawings and, in particular, to PIGURE 1, ther~ is shown one embodimcnt of this invention illustrated in cross-section, indicated generally by the numeral 10 The waste gases flow from their source, through the conduit 11 and up to the conduit 12 in accordance with arrows 14. Conduit 12 is of diameter Dl.
There is a second larger, outer conduit 16 of diameter D2, which is closed at the bottom around the inner conduit 12, into which primary combustion air is flowed under selected pressure by means of blower 17, in accordance with arrow 19. The air flow from the blower flows into the bottom of the annular space 18, between the inner and outer conduits. The annular space 18 between the inner 12, and outer 16, conduits is designated as the first annular space The air flow 19 from the blower 17 may enter the space 18, axially or radially, in which case it will flow vertically in the first annular space in accordance with arrows 20. Alternatively, the blower can be mount-ed tangentially to the conduit 16, in which case the air will flow upwardly in the form of a helix in accordance with arrow l9A The helical flow adds turbulence, which assists in the mixing of air and gas.
The second conduit 16 may be reduced in diameter above the point 23 to the diameter of 24, for the purpose of increasing the velocity of the upward flow of air in the space 25. The diameter of this reduced conduit 24 is designated D2A.
Above the top of the inner conduit 12 there is a closed cylindrical object or obstacle 34, which has a curved bottom surface and a curved top surface. It is supported by pipe 38, which is supported by spacers 40, in-: side of, and coaxial with the inner conduit 12. There is a vertical gap between the top of the conduit 12 and the obstacle 34 for the outflow of gases in accordance with arrows lS. The obstacle is of outer diameter D3A.
It is preferred that the top 36 of the obstacle 34 be above the top of the conduit Z4.
A shroud 26 of outer ~iameter D3 substantially, not necessarilydimensionally, eq~al to D3A of the obstacle 34 is fastened to the outer surface of the conduit 12 and the space between the conduit 12 and i 35S
the shroud 26 is filled with a refractory material 30.
This may be a castable material, not necessarily refractory, since the temperature at this point does not warrant refractory material. The top surface of the refractory material defines a conical passage 32 leading from the inside of the conduit 12, out into the second annular space 25 at a point substantially at the vena contracta of the air flow between the obstacle 34 and the top portion of the outer conduit 16. The approximate vena contracta is shown by dotted line. This second annular space is of selected inner and outer diameter, such that under the rapid flow of the primary combustion air 20, mixing with the out-wardly flowing gases 15, there will be a rising annular column 44 of gas and air substantially vertically from the second annular space in accordance with arrows 42. Means such as 48 are provided for igniting the gas. Therefore, there will be flame and hot air and gas rising above the top of the flare.
The purpose of the shroud 26 is to decrease the radial width of the second annular space 25 to in-crease the flow velocity of primary air 42 prior to - mixing with the gas flow 15.
The preferred value of the ratio D2/Dl is approximately 1-7. It can be larger or smaller depend-ing on the desired flow velocity of the gas-air mixture in the second annular passage. The preferred value of flow velocity is 75 ft./sec., but can be as high as 200 ft./sec. or more, or as low as 50 ft./sec., depending on the composition of the waste gas and its hydrogen to carbon ratio.
; _ 6 _ Because of the high velocity of the rising air/
gas mixture 44, secondary combustion air will be induced radially inwardly and outwardly, in accordance with arrows 46 into the outer surface 50 of this annular column 44. Also, there will be a reduced pressure directly above the obstacle 34, which will cause a downflow of atmospheric air 54, which will then be deflected outwardly into the inner surface 52 of this annular wall of gas. Because of the relatively large diameter of the obstacle 34 and the outer conduit 24 there will be a very large surface area for contact and mixing between the induced secondary air 46 and the rising column 44. Also, there will be a large contact area of the inner sur-face 5Z, which will likewise be receiving and mixing with the induced secondary air 54.
Because of the relatively narrow radial dimension of the annular column the penetration depth required of the atmospheric air in order to contact the entire volume of gas in the annular wall will be very much less than that required when the rising column of gas is in the form of a solid cylinder. Consequently, the efficiency of induction and contact of secondary air with the rising column of gas and primary air, : will make this embodiment very efficient in the smoke-less combustion of very large flows of waste gases, without substantial increase in the amount of electrical energy required to provide the pressurized primary air.
Because of this greater efficiency of mixing of the primary air with the waste gases and the more efficient induction and mixing of secondary air, the embodiment shown in FIGURE 1 is more efficient than the prior art devices and, therefore, can handle much larger flows of gas with the same amount of energy required for pressurizing the primary air.
Experience shows that primary air flow in the quantity of about eight to ten percent of the total stoichiometric flow is adequate to provide smokeless combustion of very large flows of gas.
Referring now to PIGURES 2 and 3, there are shown two views in cross-section taken acro~s the planes
2-2 and 3-3, respectively, of FIGURE 1. The drawings are self-explanatory and identical numerals are used to identify identical parts.
An improvement in the first embodiment shown in FIGURE 1 is illustrated in FIGU~ES 4-7. The improve-ment lies in the use of a plurality of circumferentially spaced radial baffles 60 across the second annular - passage 25. While four such baffles are shown, there can be any desired number. The baffles are flat bars which extend from the outer conduit 24 transverse to the air-gas flow, up to the wall of the obstacle 34.
They can be attached, as by welding 68 to outer conduit 24, or to both 24 and 34. Air-gas flow in passage 25, which is not covered by baffles is unimpeded, but the gas-air flow velocity is increased by the reduction of cross-section.
The purpose of the baffles is to cause accelerated indraft or induction of secondary air 70, FIGURES 4 and 7, to the area above the obstacle for enhancing burning.
The air 70 moving inwardly over the baffles adds to the flow of secondary air 54.
This induction effect exists because when a baffle such as those shown in FIGURES 3-7 is transverse to (or blocks) flow, as in passage 25, where the flow 42 is at significant velocity, the pressure above the baffle is reduced according to V2/2g flow energy of 42. If the pressure of air immediately adjacent to the top of 24 is atmospheric, the low-pressure at the upper suxface of the bafle causes air flow 70, and since the pressure above obstacle 36 is equally low, the air thus induced flows to the area above 36 to add to 54.
The baffles may be either solid, or may be per-forated with closely adjacent ports 66, which are sub-stantially aligned as in FIGURE 6 for continuous ignition across the baffle because of air travel to ~; their vicinity. The ba~fles may be perpendicular to -~ the wall of the outer conduit or at a selected angle upwardly or downwardly to the horizontal The length of the reduced diameter D2A portion 24 above point 23 is very short as compared to the length of conduit 16 in order to minimize the distance traveled by the high velocity air flow 42 and thus minimize linear pressure drop within the annular space 25. This reduces the energy demand that would otherwise be necessary to overcome excessive pressure drop. In a typical field service situation the length of portion 24 is about three feet while the length of conduit 16 can be upwards of 200 feet. The flow velocity of air in space 18 is but a fraction of the velocity as the air passes the orifice 23 (75 feet per second preferred) into space 25, the ratio being a function of D2A to D2.
While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement o components without departing from the spirit and scope of this disclosure. It is undexstood that the invention is not limited to the embodiments set forth herein for purposes of exemplifica-tion but is to be limited only by the scope of the attached claims, including the full range of equivalency to which each element or step thereof is entitled.
_ 10 --
An improvement in the first embodiment shown in FIGURE 1 is illustrated in FIGU~ES 4-7. The improve-ment lies in the use of a plurality of circumferentially spaced radial baffles 60 across the second annular - passage 25. While four such baffles are shown, there can be any desired number. The baffles are flat bars which extend from the outer conduit 24 transverse to the air-gas flow, up to the wall of the obstacle 34.
They can be attached, as by welding 68 to outer conduit 24, or to both 24 and 34. Air-gas flow in passage 25, which is not covered by baffles is unimpeded, but the gas-air flow velocity is increased by the reduction of cross-section.
The purpose of the baffles is to cause accelerated indraft or induction of secondary air 70, FIGURES 4 and 7, to the area above the obstacle for enhancing burning.
The air 70 moving inwardly over the baffles adds to the flow of secondary air 54.
This induction effect exists because when a baffle such as those shown in FIGURES 3-7 is transverse to (or blocks) flow, as in passage 25, where the flow 42 is at significant velocity, the pressure above the baffle is reduced according to V2/2g flow energy of 42. If the pressure of air immediately adjacent to the top of 24 is atmospheric, the low-pressure at the upper suxface of the bafle causes air flow 70, and since the pressure above obstacle 36 is equally low, the air thus induced flows to the area above 36 to add to 54.
The baffles may be either solid, or may be per-forated with closely adjacent ports 66, which are sub-stantially aligned as in FIGURE 6 for continuous ignition across the baffle because of air travel to ~; their vicinity. The ba~fles may be perpendicular to -~ the wall of the outer conduit or at a selected angle upwardly or downwardly to the horizontal The length of the reduced diameter D2A portion 24 above point 23 is very short as compared to the length of conduit 16 in order to minimize the distance traveled by the high velocity air flow 42 and thus minimize linear pressure drop within the annular space 25. This reduces the energy demand that would otherwise be necessary to overcome excessive pressure drop. In a typical field service situation the length of portion 24 is about three feet while the length of conduit 16 can be upwards of 200 feet. The flow velocity of air in space 18 is but a fraction of the velocity as the air passes the orifice 23 (75 feet per second preferred) into space 25, the ratio being a function of D2A to D2.
While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement o components without departing from the spirit and scope of this disclosure. It is undexstood that the invention is not limited to the embodiments set forth herein for purposes of exemplifica-tion but is to be limited only by the scope of the attached claims, including the full range of equivalency to which each element or step thereof is entitled.
_ 10 --
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A flare for smokeless combustion of vented waste gases, com-prising:
(a) an inner vertical conduit of diameter D1, for the upward flow of waste gases for burning;
(b) an outer vertical conduit of diameter D2 larger than D1, substantially coaxial with said first conduit, forming a substantially enclosed chamber thereabout open at the top and having a first annular pas-sage between the two conduits, and connected at the bottom with an air mover means through which primary combustion air is forced at greater than atmospheric pressure by said air mover means;
(c) closed cylindrical obstacle means having an upwardly curved bottom, said obstacle of diameter D3A greater than D1, but less than D2, supported axially above the top of said inner cylinder by a selected dis-tance, and forming a second annular passage between said obstacle means and said outer conduit;
whereby said waste gas is deflected by said curved bottom radial-ly upwardly and outwardly to intersect and mix with the rising column of primary combustion air flowing in said second annular passage;
(d) means to flow said primary air into said first annular passage sufficient to cause velocity flow of said air in said second annular passage of at least 50 feet per second; and (e) means to ignite said mixture of gas and air at the top of said second passage.
(a) an inner vertical conduit of diameter D1, for the upward flow of waste gases for burning;
(b) an outer vertical conduit of diameter D2 larger than D1, substantially coaxial with said first conduit, forming a substantially enclosed chamber thereabout open at the top and having a first annular pas-sage between the two conduits, and connected at the bottom with an air mover means through which primary combustion air is forced at greater than atmospheric pressure by said air mover means;
(c) closed cylindrical obstacle means having an upwardly curved bottom, said obstacle of diameter D3A greater than D1, but less than D2, supported axially above the top of said inner cylinder by a selected dis-tance, and forming a second annular passage between said obstacle means and said outer conduit;
whereby said waste gas is deflected by said curved bottom radial-ly upwardly and outwardly to intersect and mix with the rising column of primary combustion air flowing in said second annular passage;
(d) means to flow said primary air into said first annular passage sufficient to cause velocity flow of said air in said second annular passage of at least 50 feet per second; and (e) means to ignite said mixture of gas and air at the top of said second passage.
2. The apparatus as in claim 1, including a closed cylindrically shaped member extending from the outer surface of said inner conduit out to a diameter substantially equal to D3A; a space of selected axial dimension between the top of said cylinder and the base of said obstacle;
whereby said gas will flow through said space into said second annular passage.
whereby said gas will flow through said space into said second annular passage.
3. The apparatus as in Claim 2, in which said cylindrically shaped member is formed of refractory material.
4. The apparatus as in claim 1, including a reduction of diameter of said outer vertical conduit, near its top, equal to D2A, which is greater than D3, to provide a selected radial width across said second annular passage.
5. The apparatus as in claim 1, including means to cause said pri-mary combustion air to flow helically upward.
6. Apparatus of claim 1, the location of the outlet of the inner conduit below the top of the outer conduit at a point of vena contracta-induced maximum velocity in the flow of said primary air in the second annular passage for maximum air-waste gas mixture turbulence.
7. Apparatus of claim 1, including a plurality of equally spaced baffles extending across the flow of air-gas mixture in the second annular passage adjacent the top of the outer conduit.
8. Apparatus of claim 7 wherein the baffles include at least one opening whose axis is parallel to the axis of the outer conduit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US7864679A | 1979-09-24 | 1979-09-24 | |
| US78,646 | 1979-09-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1161355A true CA1161355A (en) | 1984-01-31 |
Family
ID=22145384
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000360813A Expired CA1161355A (en) | 1979-09-24 | 1980-09-23 | Large capacity air-powered smokeless flare |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0026067B1 (en) |
| JP (1) | JPS5653311A (en) |
| CA (1) | CA1161355A (en) |
| DE (1) | DE3068217D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6494710B2 (en) * | 2000-08-22 | 2002-12-17 | Korea Institute Of Science And Technology | Method and apparatus for increasing incineration capacity of the ground flares by using the principle of tornado |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4486168A (en) * | 1981-06-20 | 1984-12-04 | The British Petroleum Company P.L.C. | Flare |
| GB2292452B (en) * | 1994-07-26 | 1998-03-25 | Airoil Flaregas Ltd | A flare tip structure and a method of disposal of waste gas utilising such a structure |
| US9970657B2 (en) | 2013-01-18 | 2018-05-15 | Steffes Corporation | Pressure relief valve with rotating damper |
| US9970658B2 (en) | 2013-01-18 | 2018-05-15 | Steffes Corporation | Pressure relief valve with rotating damper |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1805066A (en) * | 1928-05-02 | 1931-05-12 | Andrieux Pierre Jule Justinien | Gas burner or nozzle |
| GB695477A (en) * | 1950-10-03 | 1953-08-12 | Affiliated Gas Equipment Inc | An entrainment device for obtaining a combustible fuel-air mixture in or for gas burner apparatus |
| US3817695A (en) * | 1972-06-13 | 1974-06-18 | Zink Co John | Airductor flare |
| US4036580A (en) * | 1976-06-04 | 1977-07-19 | John Zink Company | Turbine-driven air-powered flare |
| US4099908A (en) * | 1976-08-13 | 1978-07-11 | Martin Josef Beckmann | Low pressure gas burner |
| US4188183A (en) * | 1977-03-21 | 1980-02-12 | John Zink Company | Better use of gas discharge energy for smoke suppression |
-
1980
- 1980-09-10 DE DE8080303164T patent/DE3068217D1/en not_active Expired
- 1980-09-10 EP EP80303164A patent/EP0026067B1/en not_active Expired
- 1980-09-22 JP JP13222880A patent/JPS5653311A/en active Pending
- 1980-09-23 CA CA000360813A patent/CA1161355A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6494710B2 (en) * | 2000-08-22 | 2002-12-17 | Korea Institute Of Science And Technology | Method and apparatus for increasing incineration capacity of the ground flares by using the principle of tornado |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5653311A (en) | 1981-05-12 |
| EP0026067A3 (en) | 1981-06-10 |
| EP0026067A2 (en) | 1981-04-01 |
| EP0026067B1 (en) | 1984-06-13 |
| DE3068217D1 (en) | 1984-07-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |