US2802521A

US2802521A - Waste gas burner

Info

Publication number: US2802521A
Application number: US149797A
Authority: US
Inventors: Oliver F Campbell; William H Decker
Original assignee: Sinclair Refining Co
Current assignee: Sinclair Refining Co
Priority date: 1950-03-15
Filing date: 1950-03-15
Publication date: 1957-08-13
Anticipated expiration: 1974-08-13

Description

Aug. 13, 1957 o. F. CAMPBELL ETAL WASTE GAS BURNER 2 Sheets-Sheet l Filed March l5, 1950 INVENTORs Aug. 13, 1957 o. F. CAMPBELL ETAL 2,802,521 l WASTE GAS BURNER Filed March l5, 1950 Sheets-Sheet 2 Riff/- ff 20 E19@- ATTORNEYS United States Patent 2,802,521 A WASTE GAS BURNER Dliver F. Campbell and William H. Decker, Whiting, Ind., assignors to Sinclair Refining Company, New

York, N. Y., `a corporation of Maine Application March 15, 1950, Serial No. 149,797 11 Claims. (Cl. 158-115) Our invention relates to an improved emergency waste gastlare and 'a safe and reliable m-ethod for burning waste combustible gases of widely Varying he-at content at widely varying rates of dlow. It particularly provides economical and reliable means for the safe and smokeless combustion of large quantities of petroleum refinery gases during emergency or shutdown periods in the renery.

`Refinery evolution and the increasing attention of the public authorities to the problem of atmospheric polution have combined to make the safe and effec-tive disposal of waste refinery gases significant. The trend in refineries `has been toward lar-ger units increasing gas production, toward new processes `such .as catalytic cracking producing greater volumes of light gases and toward more process-es handling and employing light gases. At the same time the dangers of smog and gaseous contamination ofthe atmosphere to health and the annoy-` ance of lsmoke in the lvicinity of cities have Aattracted the attention of public authorities and in some eases have invi-ted restrictive regulation. The problem of providing for adequate disposal of refinery gases under varying renery conditions is a severe one because gas storage space cannot economically be provi-ded for all contingenices or even for peak production levels. lf the waste gases are to be burned, they must be burned without substantial generation of smoke and without endangering renery equipment orl personnel. A flare designed 4to burn waste ygases must be capable of handling quantities of gas varying from .substantially Zero flow to rates las high as 250,000 cubic` `feet per hour. The gas may vary in heat content `from 500 iB. t. u. to as high as 2,500 \B. t. u. per cubic foot and may contain relatively high percentages of We-t fractions. The gas may be at pressures ranging from Iapproximately atmospheric to as high as 25 p. s. i. g. A useful waste gas flare must "be capable of handling gases under these widely varying conditionsy and must be capable of burning such gases without generating appreciable quantities of smoke. Such a are' also must be low in cost and simple to construct -ande-mustbe'extremely rugged to stand up under sustainedV periods of highv gas combustion rates. llt must be substantially fool-proof in operation and should be -provided with positive typeignition pilot burners which can be operated remotely.

According to Vour invention, we provide a bu-rner assembly situated for the sake of safety lat the end of an elevated gas-pipe of large section. The burner assembly comprises a cap plate supported .at a distance from the end of thepipe so as to provide la peripheral gas exitjof' greater area than the cross-sectionalA area of the pipe and further -comprises a plurality of steam jets surrounding theA gas exit. We have found that the available energy contained in the high pressure steam provides adequate mixing of the gases to be burned with combustion :air so as t-o obtain Isultastantially smokeless p combustion by ejecting the steam at high pressure :around the gas exit. Preferably, the ejection means comprises a .steam ring which isperforated on its upper side so, l,

las to fact as an aspirating device. The ejected steam then provides the necessary quantities of air and effects turbu- 'lent fmxing offthe air "with the gases to *beV burned so .that smokeless combustion results.

A metal shroud surrounding the burner assembly is provided to act as a partial mixing chamber. A flame arresting means is interposed in the gas pipe between the gas exit and the point of supply. A pilot burner system which can be operated remotely is provided in association with the burner -assembly so as to insure positive ignition.

Our invention will be described by reference'to the accompanying drawings. Figure 1 represents a view of a vertical type emergency gas burner in side elevation with parts broken :away or inverted. Figure 2 represents av section upon the lines 2-2 of Figure l. Figure 3 represents an enlarged view of the upper portion of ,the

burner including the burner assembly partly in section along lines 3-3 of Figure 4. Figure 4 represents a top plan view of the burner assembly. Figure 5 represents an enlarged View of a portion of the pilot burner ass-embly visible in Figure 3. talcen along lines 6-6 of Figure 5.

.The emergency gas burner iadvantageously' is Ia tall is supplied to the gas standpipe 10 through section 124 and through gas main 14.

A llame arrestor designed to prevent liareback of gases is situated on top of the lstandpipe 10 and is housed in section 15. The -tlame arrester may consist of` a series of interlocking bars forming a large area of cooling surface. A second standpipe or

flare pipe

16, 25 inches in diameter by approximately l0 feet high, is mounted on top of the ame arrestor housing 15. The top of the ilarepipe 16 is capped with a flat circular plate'17 supported ,at its periphery by steel stripsor slats 18, 6 inches in lengt-h `arranged so that Ithe open 4area lbetween the supporting strips is slightly greater than the area ofthe flare :pipe 16 itself. The structure of the cap plate 17 and supporting strips 18 is better seen in Figures 3l an-d 4. Advantageously, the supporting slats 18 of the burner assembly are set lat an `angle of `approximately 45 so that a tangential swirling moti-on Vis imparted to the released gases which will aid considerably in mixing the gases with the incoming air. The top of the capplate 17 advantageously is protected from high temperatures by application of applastic refractory material. At the elevation of the burner end of flare pipe 16, :a steel shroud 19 is mounted by means of gusset plates 20. -As

and 'is supported by gusset plates 20. The steam ringY 21 is drilled along its upper sur-face with seventy-two la-inch holes to provide `for the injection ofihigh pres-` sure steam Isupplied through a 2-inch steam line 22. Steam line 22 is insulated andconnected by flexible connection 23 and connection 24 to .a steam header 25. Steam flow may be controlled by tmeans of block valve 26. Advantageously iturbulent mixing of Patented Aug. 13, 1957 Figure 6 is a sectional view- K @if thib-V release gases is promoted -by drilling the injection-holes in steam ring 21so that they are slanted inthe, same4 3 direction as the supporting strips or slats 18 in the gas exit area. Y

The pilot burner assembly comprises three 4-inch pilot guide pipes27 which are symmetrically varrangedraround are pipe 16 with their upper ends liushv with the bottom of the Vgas exit in the burnerV assembly. The pilot guide pipes 27 are each provided with a l-inch slot 28 extending its entire length and opening outwardly from the center of the burner. The details of the pilot burner assembly are better seen in Figures 3, 4, and 6. The lower end ofthe pilot guide pipes 27 is covered by a conical steel shield 29 to protect spark igniters 30 from direct flame impingement or ameradiation. Spark ig-Y niters 30 are high tension spark plugs mounted in opposing pairs in each of the pilot guide pipes 27 approximately 6 inches from the lower end. The spark igniters 30 are tied to high tension transformer boxes (not shown) and a remotely located push button station is provided for spark ignition. In the center of each of pilot guide pipes 27 is installed a single 3winch John Zink type ST pilot burner 31. This burner is a simple air-mixing type gas jet and each pilot burner 31 is provided with a premixing chamber 32 below the bottom end of each pilot guide pipe 27. The burners of pilot 31 are located approximately 6 inches below the top end of the pilot guide pipes 27. Each of the three pilot burners 31 is connected through gas supply ring 33 to a single gas supply header 34 which is provided with a block valve 35 at the base of pipe 12 for remote operation. In order to provide for ignition of pilot burners 31 each of the individual pilot guide pipes 27 is supplied with three 1t-inch pipe leads 36 through a header 37 and ring gas supply pipe 38, which is supplied through l-inch gas line 39. Gas line 39 is provided at the base of standpipe 12 with a flexible connection 40 and may be controlled remotely by block valve 41. The pipe leads 36 are arranged so that they project through the 1-inch slot 28 in pilot guide pipes 27 and are spaced approximately equi-distant` along the length of pilot guide pipes 27. o

In order to place the burner in operation, the spark igniter circuit is closed, and the gas supply block valve 41 to pilot guide pipes 27 is opened. As soon as ignition is assured, as may be seen by ame covering the: entire length of pilot guide pipes 27., Vthe gas supply of block valve 35 to pilot burners 31 is opened. When it is evi dent that pilot burners 31 are inservice, the block valve 41 controlling the pre-'ignition gas flow to pilot guide pipes 27 is turned off. At the same time the igniter circuit is open since there is no need to maintain continued exitation of the spark plug. The burner is `now ready for emergency tiring of dump gases. When daring begins, the block valve 26 supplying steam to steam aspirat,

ing yring 21 is opened slowly and is adjusted so that theY rate of steam ow is such as to provide `for smokeless combustion. The quantity of steam required is a function of the quantity of gas being burned, the B. t. u. value of the gas and the pressure head of the dump gases. If at any time during actual operation, pilot burners 31 are extinguished, the ignition process is repeated. In test operation, it has been found that the burner may be readily ignited by employing the pilot burner systernof our invention and that the pilot ames are stable and apparentlyunaifected by high wind or heavy rain conditions. Thus, positive ignition of the vmain dump gas stream is assured. At the initiation of the test run, gas was released from the main refinery gas holdery 'atv a rate of about 130,000 cubic feet per hour. At the vstart no steam Vwas used and tremendousquantities of heavy black smoke were produced. When steam was admitted to thesteam ring, the Ysmoking condition cleared up very quickly. Satisfactory mixing was shown by the fact that it was almost impossible to directly observe the ame, and the dame produced was excessively bright without smoke. During the testperiod, approximately 4,200 to 4.500 pounds per. hour of 125 pounds steam wereV eme 4 I ployed for the dumping rate of 130,000 vcubic feet per hour. The gas was estimated to have a B. t. u. value of approximately 1,300 B.t. u.s per cubic foot. The` gas was supplied to the burner at a pressure of only several inches of water from ak water-sealed gas holder. Our invention provides a simple, safe and reliable system for assuring smokeless combustion of refinery .gases under emergency dumping or waste an'ng conditionsnby utilization of the energy content of high pressure steam or other gas to supply the desired amount of combustion and assure turbulent admixture. .Our invention provides a burner and method of operation that Vassures substantially smokeless combustion over a wide` range of4 gas rates from substantially zero ow to as high as 250,000 cubic feet per hour or more. VGasesranging in B. t. u.

content from 500 B. t. u. to 3,000 B.1t.`u. per cubicfoot. are equally well handled, Vand operation is satisfactory over a range of a few ounces to 25 p. s.. i. g. or more.` Thus a means is providedfor emergency disposalof gases in the event of emergency shutdown of a crackingunit or in the event of a sudden drop in the normall burning capacity of the renery Yso that the refinery gas holders are overloaded and their water-seals broken through gas overflow. On the other hand, our invention provides a useful means for disposing of small amounts of gas vented into the refinery gas system during the usual daily testing of safety valves in units such as propane solvent treating where large quantities of gas under high pressure are employed. Y

The combustion of gases according to our invention is'for all practical purposes instantaneous so that close adherence to existing smoke regulations is assured. Because of the simplicity of the burner, it is simple to construct at low cost. The use of high alloy materials may be avoided by the use of suitable plastic refractory matef rials since all metal surfaces exposed to llame radiation or flame impingement may be readily protected. The

operated remotely from any location.

commenced the steam or air or gas required could be supplied in direct relationship to theY amount of gases to be burned. Such a control valve may be operated by pressure, by :Elow or by a combustion` control means suchV as a flame detectoror haze gauge. The burner requires very little ground space and may be adapted to installation on top of various structures, such as-large refinery stills.:

or buildings. The burner maybe locatedhoweverat grade in a horizontal position. A number Vofsmallerunits tiring into a target Wall may be employed. Ob-

viously a number of changes may be effected intheburner design and method of operation we have described. l

Forfexample, a plurality of steamrings or a plurality of steam supply pipes to the steam ring may be employed tov obtain improved mixing and pressure control. Irl-- 1 stead of a circular steam ring, a pluralityV `of individualV small venturi sections may be arranged ysyir'imetxjcally around the gas exit area. supplied by individual small steam supply'lines. Also the metal shroud section surrounding the burner assemblyY may be constructed with advantage in the formk of a large' venturi section in order to assistin supplying-air'to 'the burner proper. Combustion air or gascould belemployed in place of the steam mixing medium. .Y i K We claim: Y i i 7 1. A11r emergency gas Hare' which comprises aufeten-gv gated gas pipe; a burner assembly comprising a'eap. plate.

The venturi sections may @be supported at a distance from the end of the pipe so as to p provide a peripheral gas exit of greater area than the cross-sectional area of the pipe, and a plurality of steam jets positioned around said end of said pipe and directed across the path of gas owing from said gas exit; an open ended shroud of closed side wall construction having a section larger than said gas pipe mounted coaxially therewith and surrounding the burner assembly, the inner end of said shroud being positioned inwardly of the outer end of said gas pipe and the outer end of said shroud being positioned outwardly of said cap plate; ilarne arresting means interposed in the pipe between the gas exit and the point of gas supply; means for supplying steam to said steam jets; and a pilot burner assembly comprising at least one open ended pilot guide pipe mounted lengthwise of said gas pipe with the outer end of said guide pipe adjacent said peripheral gas exit and positioned between said gas pipe and said steam jetsv and with the inner end of said guide pipe positioned inwardly of the inner end of said shroud, a slot in said guide pipe extending lengthwise thereof and opening outwardly from said gas pipe, and pilot llame ignition means mounted in said guide pipe including a pilot burner at the outer end of said guide pipe, means for supplying gas to the inner end of said guide pipe, and spark ignition means at the inner end of said guide pipe for ignition of gas in said guide pipe.

2. The gas liare of claim 1 in which the plurality of steam jets of the burner assembly represent a perforated ring pipe surrounding the gas exit.

3. The gas flare of claim 1 in which the cap plate is supported by a plurality of spaced slats set at an angle of approximately 45 with a plane through each slat and the axis of the gas pipe.

4. The gas flare of claim 1 in which the shroud is constructed in the form of a venturi section surrounding the burner assembly.

5. An emergency gas flare which comprises an elongated gas pipe; a burner assembly comprising a cap plate supported at a distance from the end of the pipe so as to provide a peripheral gas exit of greater area than the cross-sectional area of the pipe and a plurality of steam jets positioned around said end of said pipe and directed across the path of gas llowing from said gas exit; an open ended shroud of closed side wall construction having a section larger than said gas pipe mounted coaxially therewith and surrounding the burner assembly, the inner end of said shroud being positioned inwardly of the outer end of said gas pipe and the outer end of said shroud being positioned outwardly of said cap plate; flame arresting means interposed in the pipe between the gas exit and the point of gas supply; means for supplying steam to said steam jets; a pilot burner assembly comprising a plurality of open ended pilot guide pipes mounted lengthwise of said gas pipe and symmetrically disposed about said gas pipe with the outer end of each of said guide pipes adjacent said peripheral gas exit and positioned between said gas pipe and said steam jets and with the inner end of each of said guide pipes positioned inwardly of the inner end of said shroud, a slot in each of said guide pipes extending lengthwise thereof and opening outwardly from said gas pipe, pilot flame ignition means mounted in each of said guide pipes including a pilot burner at the outer end of said guide pipe, spark ignition means at the inner end of said guide pipe for ignition of gas in said guide pipe, means for supplying gas to the inner end of said guide pipe, means for supplying gas intermediate the length of said guide pipe, and a shield mounted around the gas pipe for covering the spark ignition means.

6. An emergency gas are which comprises a vertically elongated gas standpipe mounted on a swivel base; flame arresting means mounted on the standpipe; a vertically elongated flare pipe mounted on the flame arresting means; a burner assembly comprising a cap plate supported upwardly from and transversely to the end of the flare pipe so as to provide a peripheral gas exit of greater area than the cross-sectional area of the pipe and a plurality of steam jets positioned around said end of said pipe and directed across the path of gas flowing from said gas exit; an open ended annular shroud of a diameter larger than said are pipe mounted coaxially therewith and surrounding the burner assembly, the inner end of said shroud being positioned inwardly of the outer end of said gas pipe and the outer end of said shroud being positioned outwardly of said cap plate; means for supplying steam to said steam jets; and at least one open ended pilot guide pipe mounted lengthwise of said gas pipe with the outer end of said guide pipe adjacent said peripheral gas exit and positioned between said gas pipe and said steam jets and with the inner end of said guide pipe positioned inwardly of the inner end of said shroud, a slot in said guide pipe extending lengthwise thereof and opening outwardly from said gas pipe, and pilot llame ignition means mounted in said guide pipe including a pilot burner at theV outer end of said guide pipe, spark ignition means at the inner end of said guide pipe for ignition of gas in said guide pipe, means for supplying gas to the inner end of said guide pipe, and means for supplying gas intermediate the length of said guide pipe.

7. An emergency gas flare comprising a gas pipe for conducting waste gas; a burner assembly mounted on said gas pipe having a cap plate supported outwardly of the outer end of said gas pipe and transversely thereto to provide a peripheral gas exit of greater area than the cross-sectional area of the pipe, and aspirating means positioned at and around said outer end of said gas pipe and directed to eject a fluid across the path of Waste gas owing from said peripheral gas exit; and an open ended shroud having a closed side wall forming a mixing chamber surrounding said burner assembly and said gas pipe, the inner end of said shroud being positioned inwardly of the outer end of said gas pipe and the outer end of said shroud being positioned outwardly of said cap plate.

8. An emergency gas are in accordance with claim 7 in which the aspirating means includes a perforated ring pipe surrounding the peripheral gas exit.

9. An emergency gas ilare in accordance with claim 7 in which the cap plate is supported by a plurality of spaced slats set at an angle of approximately 45 with a plane passing through each slat and the axis of the gas pipe.

10. An emergency gas flare in accordance with claim 7 in which the shroud is constructed in the form of a Venturi section surrounding the burner assembly.

11. An emergency gas ilare in accordance with claim 7 and including a pilot burner assembly comprising an open ended guide pipe mounted lengthwise of said gas pipe with its outerend adjacent said peripheral gas exit positioned within the space enclosed by said shroud and with its inner end positioned inwardly of the inner end of said shroud, a pilot burner positioned at the outer end of said guide pipe, and a slot extending lengthwise of said guide plpe and opening outwardly from said gas pipe.

References Cited in the le of this patent UNITED STATES PATENTS 1,302,914 Goreau May 6, 1919 1,561,848 Green Nov. 17, 1925 1,669,463 Garden May 15, 1928 2,365,102 Olds Dec. 12, 1944 2,389,027 Corbin et al Nov. 13, 1945 2,460,016 Kuhn June 25, 1949 2,480,230 Elster Aug. 30, 1949 2,506,922 Schellentrager et al May 9, 1950 2,537,091 Rodman et al. Ian. 9, 1951 FOREIGN PATENTS 191,309 Germany Nov. 5, 1907