US2506972A

US2506972A - Flare stack tip

Info

Publication number: US2506972A
Application number: US733402A
Authority: US
Inventors: William S Schellentrager; Edward S Bale; Howard G Briggs
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1947-03-08
Filing date: 1947-03-08
Publication date: 1950-05-09
Anticipated expiration: 1967-05-09

Description

y 1950 w. s. SCHELLENTRAGER 'ETAL 2,506,972

FLARE STACK TIP Filed March 8, 1947 s/ as 27 1 1/ 11/ 1 1/, 41,! I f; u/ I, I I 1 2 i: I z @i 24 I I I I l l I Z 5' 5! g a l 4 I I l 9 1 r 26 I. '1 i 1 I, I 1 l I g l a4 2, I d X l A I v f' 37 9 f v F 36 a g E I mvzmoas WILLIAM s. SCHELTLENTRAGER EDWARD s. BALE HOWARD c. amass THEIR ATTORNEYS Patented May 9, 1950 I 2,506,972 FLARE STACK TIP William s schellentrager, Chagrin Falls, Edward S. Bale, Cleveland Heights, and Howard G. Briggs, Shaker Heights, Ohio, assignors to The Standard Oil Company; Cleveland, Ohio, a cor poratlon of Ohio Application March 8, 1947, Serial No. 733,402

. 6 Claims. 1

The present invention relates to a flare stack tip for burning the waste gas produced in a refinery or the like.

The normal operations of an oil refinery are accompanied by the. production of unavoidable quantities of combustible gas. Some of such gas must be considered waste, because there is no market for gas formed at rates that are too variable to satisfy the demands of establishments utilizing gas, and it is usually not stored in order to build upa dependable and constant source of supply because of the unjustifiable expense of such storage facilities. Furthermore, such storage would necessarily subject the gas to at least some superatmospheric pressure. Many items of apparatus in the refinery are equipped with safety valves that are designed to release combustible gas in times of emergency. In order to make the operation of such safety valves effective, it is necessary that the gas released thereby be free to escape to the atmosphere immediately and without the application thereto of any backpressure. For this reason, conduits designed to lead such combustible gas from the vicinity of the safety valves to a central discharge point cannot be equipped with compressors or pumps or the like because sudden releases of such gas will overtax their capacity and consequently result in the building up of a back pressure. Any such confinement of the gas, even temporarily, would present a real and dangerous threat of explosion within the refinery. I

The conventional method of handling combustible waste gas of this type has been to employ conduits of relatively large diameter to lead the gas from the points of origin to a large and high stack or flue so that it can be discharged to the atmosphere without permitting it to build up any back pressure. Inasmuch as this gas is often poisonous and its liberation would pollute the atmosphere, it has been the practice of refineries to burn this gas at the top of the stack. While this system has been effective in safely removing the combustible waste gas from the refineries, it has also resulted in the creation of a smoke nuisance and in considerable expense. The combustible gas which rises through the discharge flue contains insuflicient air to support complete combustion and consequently the burning of this gas has been attended by the generation of large quanties of smoke. This is not only injurious and detrimental. to the areas in the vicinity of the refinery but frequently violates local smoke ordinances. Furthermore, in windy weather, the flame at the top of the flue licks down along the outside of the stack and results in rapid oxidation and corrosion thereof with the result that large portions of the stack burn off and fall from time to time. In view of this, it has been nece:sary in the past not only to replace the stack at intervals but to rope oiT large areas surrounding the stack to prevent pieces thereof from falling on the plant personnel.

One object of the present invention, therefore, is to provide a means for discharging combustible waste gas to which no back pressure may be applied by burning it at the tip of a stack or flue with a smokeless flame.

Another object of the invention is to provide protective devices to prevent oxidation and corrosion of the stack.

Still another object of the invention is to pro-] vide means for insuring the complete combustion of combustible waste gas at the top of the stack whether said gas is discharged constantly or intermittently.

These and other objects, as well as the utility and advantages of the present invention will be apparent from the accompanying drawing and the following detailed description:

In the accompanying drawing, the sole figure illustrates one example of flare stack tip con-= structed in accordance with the principles of the present invention:

Flare stack tip l0 may be mounted upon a flue '8 (the upper portion of which is shown), in any suitable manner such as by bolting or welding together flanges 9, or it may be made integral with the flue. The flue and flare stack tip may be of any desired diameter depending upon the volumetric rate at which the waste gas is to be discharged. The height of the flue may likewise be of any dimension suitable for obtaining a desired speed of flow in the waste gas and be dependent upon the elevation and type of installations located in the vicinity. Thus, for example, the

flue may be 10 to 36" in diameter and to 250 feet high, The flare stack tip I0 is provided with a refractory or heat resistant lining I! that preferably also covers an annular plate ll fixed to the top and, if desired, supported by any suitable means such as supports l3. In order to reduce to a minimum the resistance to upward motion of gas within flare stack tip I 0, wall I thereof is preferably recessed,ras shown at It, so,- as to accommodate refractory lining I 2 in a position flush with the interior surface of flue 8. One 'or more inspirators l! are provided about the circumference of flare stack tip l0. Each of these includes a steam jet IS, a variable opening 20 for air, a venturi 2|, and a conduit 22 which may, if desired, be supported by means of brackets 24 and 23. Conduit 22 passes through the walls of flare stack tip III at an angle such that the material flowing through inspirators I1 will create turbulence and yet exert a net upward force upon the contents of flare stack tip l0. Conduits 22 may enter flare stack tip Ill so that material flowing through inspirators I1 will flow toward the center of flare stack tip III or they may be so placed as to induce the material to flow spirally along the walls in order to impart a whirling motion to the gas within flare stack tip II. The variable air inlet 20 may be any suitable type, such as for example, that used on the well-known Maxon gas burner, and steam jet I! may be supplied from any suitable source such as from a supply of waste steam that is ordinarily vented to the atmosphere or condensed and returned to steam generating facilities.

Next to opening 21 of flare stack tip ID a pilot light is housed within a wind proof housing 28 having openings 30 through which a flames of the pilot light can pass as shown at ll and 33. gas and air conducted to housing 29 by means of a conduit 32 having a length designed to give good mixing of the gas and air, no cracking of the gas and smokeless flames. Conduit 32 is provided with a venturi 34, the gas is supplied by a high pressure gas line 36 and the air is taken in through variable opening 31 which may likewise be of the Maxon burner type.

In operation, steam Jet i9 draws air through openings 20 and impels a mixture of air and steam to flow upwardly through inspirator i1 and into the upper portion of flare stack tip III. The kinetic energy of this stream tends to draw the combustible gas within flare stack tip it upwardly and brings about intimate mixing of the gas with suflicient air to support complete combustion thereof. The flames of the pilot light ignite the mixture of gas and air which thereupon burns with luminous, smokeless flame. Annular plate I i and lining i 2 effectively prevent the flame from licking the sides of the flare stack tip and the flames of the pilot light insure ignition of the mixture of gas and air leaving opening 21 of flare stack tip I0. When, for example, the wind blows from the left of the stack, as illustrated in the drawing, the mixture of gas and air leaving opening 21 will be blown over housing 23 so that the gas will be ignited by flame 33 or one or more of the other flames even though flame 3| may be blown out or back into housing 29. If, on the other hand, the wind should blow from the right, it would blow flame 3! of the pilot light further across opening 21 and thereby ignite the gas leav-, ing by way of opening 21.

It has been found that a stack having a diameter of 24 inches and a height of 200 feet, equipped with a flare stack tip having eight inspirators, each capable of inspirating approximately ten cubic feet of air per cubic foot of steam or a total of 250 cubic feet of air per minute, is capable of burning, with a luminous, smokeless flame, all but an abnormally rapid flow of waste gas, Such abnormally rapid flows, which occur seldom and only for short periods, will produce a flame that is smoky but not nearly as smolw as would be produced if the stack were not so equipped. It was alsofound that the use of such a flare stack tip did not result in the development or any back pressure on the gas within the flue.

flare stack tip may be designed to handle any desired capacity of combustion gas. But inasmuch as its volumetric capacity is dependent upon the diameter of the flue and stack tip and its capacity for burning waste combustible gas with a smokeless flame is dependent upon the amount of air injected b means of the inspirator or inspirators, the placing of a flare stack tip of this type upon the conventional stack now in use in most reflneries, does not interfere with the flow of gas and in fact induces a flow because of the suction effect of the inspirator.

It is obvious that various changes and alterations canbe made in the arrangement, form, construction, and type of the various elements herein-disclosed without departing from the scope or spirit of this invention. Thus, for example, it is within the contemplation of this invention to manually or automatically control the quantity of air injected into the flare stack tip and to so vary that amount depending upon the volume of combustible waste gas released to the flue.

circleof Z The pilot light is fed by a mixture oi?- ,1;

Furthermore, it is within the contemplation of the invention to replace the steam jets with other means for bringing about a flow of air through the inspirator. Such alternative means would, for example, be compressed gas or compressed air. It would also be possible to supply the inspirator or inspirators with air by means of centrifugal pumps or the like. The number and shape of the inspirators can be varied in an innumerable number of ways so long as the force applied to the gas within the flue by the material flowing through the inspirator is a net upward force tending to make the gas flow toward the mouth of the flare stack tip. The invention is, therefore, intended to include within its scope all changes and alterations that come within the broad meaning and scope of the appended claims.

We claim:

1. A flare stack tip mounted upon a flue for burning combustible gas passing upwardly there-' through under substantially atmospheric pressure which comprises a stack section lined with heat resistant refractory-material, an annular plate covered with heat resistant refractory material, said plate being flxed. to the upper portion of said section and'extending outwardly therefrom, a pilot light housed in a wind-proof jacket and positioned adjacent the upper end of said stack section, fgonduit means entering said stack section at an acute angle and below the upper end thereof and means for introducing air upwardly into -said stack section through said conduit means. I

2. A flare stack tip mounted upon a flue for burning combustible gas passing upwardly therethrough under substantially atmospheric pressure which comprises a stack section, an annular plate fixed to theiupper portion of said section and extending outwardly therefrom, a pilot light housed in a wind-proof jacket and positioned adjacent the upper end of said stack section, conduit means entering said stacinsection at an acute angle and below the upper end thereof and means for introducing air upwardly into said stack section through said conduit means.

3. A flare stack tip mounted upon a flue for burning combustible gas passing upwardly therethrough under substantially atmospheric pressure which comprises a stack section lined with heat resistant refractory material, a pilot light housed in a windpro'of jacket and positioned 'adJacent the upper. end of. said stack section, conduit In accordance with the present invention, 5 means entering said stack section at an acute angle and below the upper end thereof and means for introducing air upwardly into said stack section through said conduit means.

4. A flare stack tip mounted upona flue for burning combustible gas passing upwardly therethrough, under substantially atmospheric pressure which comprises a stack section lined with heat resistant refractory material and being substantially free of obstructions in the interior thereof, a pilot light housed in a windproof jacket and positioned at one side on the upper end of said stack section, an annular plate covered with heat resistant refractory material, said plate being fixed to the upper portion of said section and extending outwardly therefrom, conduit means entering said stack section at an acute angle and below the upper end thereof and'means for introducing air upwardly into said stack section through said conduit means.

5. A flare stack tip mounted upon a flue for burning combustible gas passing upwardly therethrough under substantially atmospheric pressure which comprises a stack section lined with heat resistant refractory material, an annular plate covered with heat resistant refractory material, said plate being fixed to the upper portion of said section and extending outwardly therefrom, a pilot light housed in a wind-proof jacket and positioned adjacent the upper end of said stack section, conduit means entering said stack section at an acute angle and below the upper end thereof and a steam jet for drawing air into said conduit means and injecting it upwardly into said stack section through said-conduit means.

6. A flare stack tip mounted upon a flue for burning combustible gas passing upwardly therethrough under substantially atmospheric pressure which comprises a stack section lined with heat resistant refractory material, an annular plate covered with heat resistant refractory material, said plate being fixed to the upper portion of said section and extending outwardly therefrom, a pilot light housed in a wind-proof jacket and positioned adjacent the upper end of said stack section, conduit means entering said stack section at an acute angle and below the upper end thereof and pumping means for introducing air under pressure upwardly into said stack section through said conduit means.

WILLIAM S. SCHEILEN'IRAGER. EDWARD S. BALE. HOWARD G. BRIGGS.

REFERENCES CITED The following references are of record in the a file 01 this patent:

UNITED STATES PATENTS