US3822984A

US3822984A - Flare gas burner

Info

Publication number: US3822984A
Application number: US00395522A
Authority: US
Inventors: J Straitz
Original assignee: Combustion Unlimited Inc
Current assignee: COMBUSTION UNLIMITED INC US; Combustion Unlimited Inc
Priority date: 1973-09-10
Filing date: 1973-09-10
Publication date: 1974-07-09
Anticipated expiration: 1991-07-09

Abstract

A flare gas burner for waste combustible gases from oil refineries and the like is disclosed which includes an outer stack pipe for high pressure gases having at the top thereof a plurality of outwardly extending tilted vanes with gas delivery slots, the tops of the vanes being angularly disposed in a plane with respect to radial lines through the center of the stack pipe for a swirling action of the burning gas. An optional supply of high pressure assist gas can be provided for low flow rates of high pressure gas. A supply pipe is provided within the stack pipe for delivery of low pressure gas to an annular ring at the top of the stack which ring has elongated slots in the top and side for delivery of low pressure gas for burning. A relief or emergency dump gas supply pipe is also carried within the stack pipe for delivery of gas to the top of the stack pipe for burning. A steam ring is provided carried at the top of the stack with steam delivery pipes along the high pressure vanes and with angularly disposed tips delivering steam to enhance the swirling action of the burning gas and to suppress smoke. Ignitors and pilots are shown for initiating combustion of the gases.

Description

[11] 3,822,984 July 9, 1974 United States Patent [191 Straitz, III I FLARE GAS BURNER oil refineries and the like is disclosed which includes an outer stack pipe for highpressure gases havin the top thereof a plurality of outwardl tilted vanes with gas delivery slots g at y extending the tops of the vanes being angularly disposed in a plane with respect to radial lines through the center of the stack pipe for a swirling action of the burning gas. An optional supply of high pressure assist gas can be provided for low flow rates of high pressure gas. A supply pipe is provided within the stack pipe for delivery of low pressure gas to an annular ring at the top of the stack which ring has elongated slots in the t 8. MW P m 3% l 0 m m ,3 .m 2F k r O" n ,3 mm .R D. 1 U 3 n 4 N m 31 a E 8 n a m a 3 2 U .l 7 m BM 9 4 0 1 S rum 9 S 0 2 H F W 2 n R r. 5 u m0 t i .u h 0 C P 5 u 0 n "M 9 n J CI 3 m n a 0. w m N L m .w d m v w M P S I A F A Uh l l. l l] 5 3 2 .l. 21 7 2 2 55 i l. rti

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FLARE GAS BURNER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to flare gas burners for waste gas from refineries and the like of the type wherein emergency dump high and low pressure gas can be burned independently and at the same time in smokeless condition.

2. Description of the Prior Art In industrial operations and particularly in the operation of petroleum processing refineries it becomes necessary from time to time to burn various surplus quantities of combustible gaseous materials at low pressure, high pressure or at the entire possible design gas output of the refinery due to emergency conditions. The characteristics of these gaseous materials as well as ecologi cal considerations require that they be burned and that the combustion be carried out without'discharge of unburned carbon particles (smoke) into the atmosphere.

Various combination flare gas burners have heretofore been proposed, but some of them have had serious limitations, particularly becuase of inadequate turbulence and intermixing of combustible gases, air, and steam necessary for smoke elimination.

Among the burners heretofore proposed are those shown in the U.S. patents to Verner et al., U.S. Pat. No. 2,761,496; Webster, et al., U.S. Pat. No. 2,891,607; Shelentrager, U.S. Pat. No. 2,506,972; Rodman, U.S. Pat. No. 2,537,091; Zink .et al., U.S. Pat. No. 2,779,399; Campbell et al., U.S. Pat. No. 2,802,521; Zink et al., US. Pat. No. 3,143,424; Turpin, U.S. Pat. No. Re. 27,507 and in the Canadian Patent to Williams, No. 691,894; and in the British patent to British Petroleum Co., et al., No. 795,664.

Turpin in U.S. Pat. No. Re. 27,507, shows a flare stack combustion tip at the top of the stack, with a plurality of radial arms with movable plates to control the flow and with an outside air venturi shroud to mix the air with the flare gas. The use of movable parts at the relatively inaccessible top of a flare stack is unacceptable from a reliability standpoint since ice deposits as well as likelihood of fouling or corrosion tend to interfere with the demand for availability of operation at any time. The air venturi is also unacceptable from a maintenance standpoint as the wind can cause recirculation down through the venturi causing its destruction by burning within a very short time.

None of the previous structures provide separate provisions for delivery of three different sources of combustible waste gas, i.e. low pressure, high pressure or emergency dump to a single structure where the gases can be burned independently or simultaneously in a smokeless condition.

SUMMARY OF THE INVENTION.

In accordance with the invention a flare gas burner is provided which has a stack pipe with high pressure gas introduced thereinto at the bottom, with fixed vanes extending from the top of the stack pipe angularly disposed in a horizontal plane from radial lines through the center of the pipe, the vanes having slots at their top margins for flare gas delivery, the stack'car rying a pipe for supplying low pressure waste gas to an annular ring at the top of the pipe with elongated slots for burning of the gas. A centrally disposed relief or emergency gas supply pipe is also carried within the stack pipe for delivery of relief waste gas to the top of the stack for burning. I

A steam ring can also be provided, exteriorly mounted to the top of the stack pipe, dependent upon the inherent tendency of the waste gas to develop smoke, with outwardly and upwardly extending pipes along the vanes, with steam delivery to upwardly and angularly disposed tips positioned to enhance the swirling action of the burning gases. An optional supply of high pressure assist gas can be provided to assist the high pressure gas in inducing sufficient air for smokeless buming at low flow rates. Ignitors and pilots are also shown.

It is the principal object of the invention to provide a flare gas burner which is highly effective for the combustion of waste combustible gas at different pressures by reason of the increased turbulence imposed on the combustible gas, air and steam at the top of the stack pipe.

It is a further object of the invention to provide a flare gas burner with three separate gas supply systems for delivery of gas to one location for burning at different supply pressures.

It is a further object of the invention to provide a flare gas burner of the character aforesaid in which the component parts are simple, sturdy, trouble free and require a minimum of maintenance, and which is more effective than the flare gas burners heretofore available.

It is a further object of the invention to provide a flare gas burner with effective steam delivery for smoke elimination.

Other objects and advantageous features of the invention will be apparent from the description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawing forming part hereof, in which:

FIG. 1 is a view partly in elevation and partly in vertical section of the flare gas burner in accordance with the invention; a

FIG. 2 is a top plan view of the flare gas'burner of FIG. 1',

FIG. 3 is an enlarged fragmentary vertical sectional view taken approximately on the line 3-3 of FIG. 2;

FIG. 4 is an enlarged fragmentary horizontal sectional view taken approximately on the line 4-4 of FIG. 3, and V FIG. 5 is an enlarged vertical sectional view taken approximately on the line 55 of FIG. 2.

It should, of course, be understood that the description and drawings herein are illustrative merely and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

Like numerals refer to like parts throughout the sev-' eralviews.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings, a vertical stack pipe 10 is shown, circular in horizontal cross section and the bottom of which is mounted onto the top of a flare stack (not shown) to which high pressure gas for combustion is delivered from time to time.

The pipe has carried therein a centrally disposed interior relief or emergency dump gas delivery pipe 11 connected to the supply of relief or emergency dump gas. the pipe 11 is closed at the top by an annular closure plate 12 which is provided with a central opening 13 and elongated openings 14 for delivery of the relief gas for burning as hereinafter pointed out.

The pipe 10 has carried therein and shown to one side of the pipe 11 an upwardly extending low pressure gas supply pipe 15 which has its lower terminal connected to a supply of low pressure waste combustible gas. The pipe 15 is connected to an annular ring 16 secured to the top of the pipe 10 with the pipe 11 secured to the center thereof in fluid tight relation which closes off the pipe 10 at the top. The ring 16 is provided with elongated slots 17a disposed along its top portion 18 and holes 17b around its outside perimeter 20 for delivery of low pressure gas for burning.

The pipe 10 at the top thereof below the ring 16 has extending outwardly therefrom a plurality of fixed inclined vanes 25. The vanes are shown as made of converging

side wall plates

26 and 27 closed at the bottom by a bottom wall 28 and at the outer end by an end wall 29 and with intermediate stiffeners 30 parallel to the end wall 29. The

plates

26 and 27 are separated at the top to provide a gas delivery slot 31 and at their inner ends have their interiors in communication with the interior of the pipe 10.

The inclined vanes 25 and their gas delivery slots 31 are each at an angle, in a horizontal plane, to a radial line through the center of the pipe 10 to impart a swirling motion to the gas delivered through the slots 31.

The vanes 25 preferably have disposed therealong horizontal steam delivery pipes 35 connected to a horizontal steam supply ring 36. the ring 36 can have supporting brackets 37 secured thereto and to the pipe 10 and is supplied with steam by a steam supply pipe 38.

Each of the pipes 35 has a vertically upwardly extending portion 40 and an angularly disposed terminal end 41 with a tip 42. The tip 42 can be similar to the tip shown in the U.S. Patent to Bitterlich, U.S. Pat. No. 3,463,602 and the terminal end 41 is inclined and turned or angularly disposed to direct steam to enhance the swirling action of the burning gases.

A plurality of gas pilots 43 are provided with their heads 44 or upper terminii between the vanes 25. The pilots 43 can be of the venturi air inspirating type and connected to a gas manifold ring 45 to which combustible gas is supplied through a pipe 46. The gas pilots 43 can be supported by brackets 47 secured to the pipe 10.

In order to ignite the gas pilots 43, an igniter pipe 49 is provided through which a gas flame is directed when desired. The igniter pipe 49 can be supported by brackets 50 secured to the pilot 43.

In use the pilots 43 are continuously burning, ignition being effected by flame delivered through the igniter pipe 49.

The waste gas to be burned at high pressure is delivered through the flare stack to the pipe 10 where it passes upwardly and then outwardly into the vanes 25 for delivery through the slots 31 in a plurality of sheet flame patterns as determined by the positioning of the slots 31.

If low pressure waste gas is to be burned it is supplied through pipe 15 to the annular ring 16 where it passes out through the slots 17a and holes 17b and is ignited by the pilots 43.

If high pressure gas is then introduced into the vanes 25 the burning low pressure gas assists in igniting it.

If relief or emergency dump gas is to be burned it flows upwardly in pipe 11 to plate 12 where it passes out through openings 13 where it is ignited by burning low pressure gas or by the pilots 43.

If the flare is not burning smokelessly, steam can be introduced through the pipes 35 and out the tips 42 where it serves to enhance the swirling action of the gases and suppress smoke.

in addition if the high pressure gas flow is insufficient for complete combustion high pressure assist gas can be supplied to pipe 10.

It is therefore apparent that the flare is capable of burning low pressure waste gas, high pressure waste gas or emergency dump waste gas either independently or simultaneously as dictated by the plant conditions and without smoke, for the low pressure and high pressure waste streams and with gaseous fluid such as steam or assist gas for smoke suppression.

1 claim:

1. A flare gas burner for combustible waste gas comprising an outer stack pipe connected to a supply of waste gas at high pressure,

a plurality of outwardly extending hollow vanes at the upper end of said pipe with spaces therebetween and having upwardly facing gas delivery openings connected to said stack pipe for discharge of waste gas for burning,

said vanes having their slots disposed at an acute angle to a plane including a radius and the vertical longitudinal axis of said pipe,

a low pressure gas supply pipe associated with said stack pipe,

means connected to said low pressure pipe for delivery of said gas for burning at the upper end of said stack pipe and within the confine of the surrounding vanes,

an emergency dump waste gas supply pipe associated with said stack pipe,

means connected to said dump gas supply pipe for delivery of said gas for burning at the upper end of said stack pipe and within the confine of the low pressure gas delivered to the upper end of the stack, and

means associated with said stack pipe supplying gaseous fluid for smoke suppression.

2. A flare gas burner as defined in claim 1 in which said means for burning connected to said low pressure supply pipe includes an annular manifold having elongated slots on its top and along its perimeter.

3. A flare gas burner as defined in claim 1 in which said means for burning connected to said emergency dump gas supply pipe includes a plate with openings therein.

4. A flare gas burner as defined in claim 1 in which said smoke suppression means includes members for supplying gas to the upper end of said stack pipe.

6. A flare gas burner as defined in claim 2 in which said low pressure gas supply pipe is carried within said stack pipe, and said manifold is secured to the top of said stack pipe.

7. A flare gas burner as defined in claim 2 in which said emergency dump gas supply pipe is secured to said manifold.

Claims

1. A flare gas burner for combustible waste gas comprising an outer stack pipe connected to a supply of waste gas at high pressure, a plurality of outwardly extending hollow vanes at the upper end of said pipe with spaces therebetween and having upwardly facing gas delivery openings connected to said stack pipe for discharge of waste gas for burning, said vanes having their slots disposed at an acute angle to a plane including a radius and the vertical longitudinal axis of said pipe, a low pressure gas supply pipe associated with said stack pipe, means connected to said low pressure pipe for delivery of said gas for burning at the upper end of said stack pipe and within the confine of the surrounding vanes, an emergency dump waste gas supply pipe associated with said stack pipe, means connected to said dump gas supply pipe for delivery of said gas for burning at the upper end of said stack pipe and within the confine of the low pressure gas delivered to the upper end of the stack, and means associated with said stack pipe supplying gaseous fluid for smoke suppression.

4. A flare gas burner as defined in claim 1 in which said smoke suppression means includes a steam ring with angularly upwardly extending pipes, and said pipes are provided with angularly inclined tips.

5. A flare gas burner as defined in claim 1 in which said smoke suppression means includes members for supplying gas to the upper end of said stack pipe.