US3161228A - Method of gasifying liquid fuels - Google Patents

Description

1964 w. BRODLIN 3, 61,

METHOD OF GASIFYING LIQUID FUELS Filed May 17, 1962 2 Sheets-Sheet 1 WILLI BRCDLIN INVENTOR.

ggrl 9- AGENT Dec. 15, 1964 w. BRGDLIN METHOD OF GASIFYING LIQUID FUELS 2 Sheets-Sheet 2 Filed May 17, 1962 vllal dll FIGS WILLl BRODLIN INVENTOR.

BY marl K 5;

AGENT United States Patent 3,161,228 METHOD fil GASIFYING LTQUHD FUELS Willi Rrbdlin, Allenshach am Bodensee, Germany Filed May 17, 1962, Ser. No. 1%,573 Claims priority, application Germany May 17, 1%1 1 Claim. (Cl. 153-1175) My present invention relates to a method of gasify ing liquid fuels, especially hydrocarbons such as oil, and to a device for carrying the method into practice.

An object of this invention is to provide a method of carrying out such gasification in a manner resulting in a readily combustible gas capable of being burned with a blue, relatively soot-free flame either in situ or at some other location to which the gas may be subsequently conveyed.

Various proposals are known for increasing the efficiency of burners utilizing a fuel oil. Thus, it has been found desirable to recirculate the combustion products of an inner flame, maintained within a burner tube, by means of bypass channels carrying the hot gases preferably in a burning state back to the origin of that flame at the aperture of a nozzle into the tube. This has been more fully disclosed in my copending application Ser. No. 834,245, filed August 17, 1959 and now abandoned, which described a variety of structures for creating such bypass channels and of which the present application is a continuation-in-part. These channels, however, must evidently be made of a highly refractory material to withstand the heat of the recirculated gases, it being therefore a more particular object of my present invention to provide an improved type of gasifying device, adapted to be used as a burner or as a gas generator, in which the need for such channels has been obviated.

in my aforementioned copending application I have already indicated, with particular reference to FIG. 4 thereof, that it is possible to create in a burner chan her a combustion-promoting turbulence through the introduction of a gas stream into the chamber. This aerodynamic creation of turbulence is the principle of my present invention and involves the injection of a highspeed stream of oxidizing gas such as air, along with a flow of liquid fuel to be atomized thereby, into a burner tube so as to produce a substantially conical spray which preferably contacts the Wall of the tube near its mouth and leaves around the aperture of the injection nozzle a generally toroidal pocket in which a vortex is generated by the pressure difference existing along the tube. In contradistinction to prior proposals 1 have found it essential that the air/fuel mixture circulating in this vortex contain an undersupply of air, i.e. a quantity of oxygen considerably less than the stoichiometric amount required for the combustion of the fuel. Thus, there occurs in the region of the nozzle outlet a preliminary combustion which is only partial and which serves to decompose the hydrocarbons of the mixture into readily burnable components such as hydrogen and carbon monoxide. Naturally, the same conditions are realizable if pure oxygen instead of air is admitted into the tube along with the fuel stream.

in general, the understoichiometric amount of oxygen may be supplied to the precombustion zone near the nozzle outlet in a variety of ways. This includes the feeding of the oxygen (alone or as part of an air flow) to the nozzle as an atomizing fluid for the injected fuel and therefore in the same direction as the latter, the admission of supplemental air through lateral ports in cross-flow to the ignitable mixture, and/or the aspiration of atmospheric air through the burner mouth in counterfiow to the fuel stream. Particularly the air in- 3,ll,22b Patented Dec. 15., 1964 take from this latter source can be readily limited or completely shut off by near or actual contact of the base of the spray cone with the tube wall. The angle of divergence of this cone, i.e. the angle included between its generatrices and its axis, will normally run between 10 and 30.

in most instances it will be advantageous to deliver the fuel at relatively low pressure to the nozzle aperture and to atomize it by an accompanying air or oxygen stream of high velocity, preferably ranging from at l ast 50 m./sec. to or beyond 500 m./sec., whose gauge pressure may lie between 0.5 and 5 atmospheres. The oxygen content of the atomizing air will normally be in the vicinity of 5% of the stoichiometric amount so that further oxygen, e.g. from secondary air, will be needed to sustain the partial combustion within the tube. The total oxygen content of the atmosphere in the tube falls short by, preferably, about 30% of the stoichiometric quantity as set forth in my copending application Ser. No. 155,373, filed November 28, 1961.

The invention will be described hereafter with greater detail, reference being made to the accompanying drawing in which:

FIG. 1 shows, in axial section, a gasifying device embodying the invention;

FIG. 2 is a view similar to FIG. 1, showing a modification;

FIG. 3 illustrates, also in axial sectional view, a further embodiment; and

FIG. 4 is a cross-sectional view taken on the line lVlV of FIG. 3.

The burner 10 illustrated in FIG. 1 comprises a tube 11 here shown to be metallic although it is also possible, in this and other embodiments, to use a ceramic tube clad with a refractory metallic sheath as particularly shown in FIG. 5. Tube 11 contracts at its upstream end 12 to hug a nozzle 13 whose outlet 14 emits an ignitable mixture in a conical spray 15 having an angle of divergence a of about 10%. It will be noted that the cone 15 contacts the inner wall of tube 11 at a location 26 just ahead of the tube mouth 17. Between this location and the upstream end 12 there is defined by the inner tube wall, the nozzle 13 and the cone is a generally toroidal pocket 18 into which part of the injected aerosol mist is deviated in a toroidal vortex 19 due to the pressure diiference between the high-pressure region of expanding gases at the tube mouth 17 and the low-pressure region at the nozzle outlet 14. The vortex 19 is supplied with additional air through lateral ports 20 whose effective cross-section can be adjusted by means of a ring 21 axially slidable on the tube 11. The nozzle 13 may have a construction similar to that described hereinafter with reference to FIG. 3.

When the emergent spray is ignited at the tube mouth 17, the flame flashes back into the interior of the tube to set up combustion in the region of turbulence within pocket 18 whereby the vortex 19 turns into a flame. Alternately, particularly if the gaseous output of the device is to be connected to a different location for storage or utilization, such an internal flame can be produced by the use of igniter electrodes 22, 23 as shown in PEG. 2 for a modified gasifier 10a. In the latter figure, wherein the shape of the spray cone 15a from nozzle 13:; remains substantially unchanged, the surrounding tube is shown composed of a frustoconical downstream section 11a Welded onto a cup-shaped upstream section 12a provided with the ports 219a. The inlet area of these ports 22, as in the preceding embodiment, can be regulated by suitable means not further illustrated.

Though the device llla shown in FIG. 2 may of course be used as a burner in the same manner as the device of FIG. 1, I have schematically illustrated at 24 a conduit for carrying off the gas produced at the mouth 17a of tube section 11a.

FIGS. 3 and 4 show a gasifier 10b with a straight cylindrical-discharge tube 11b, anozzle 13b producing a spray cone 15b,'a shell forming an annular housing about the upstream portion of-tube 11b which is provided with the ports 2%, and a central body forming a support for the elements referred to. This body has a channel 27 through which atmospheric air maybe admitted into the annular clearance between body 26 and the shell 25 by this ring thusenabling regulation of the air supply through ports Ztlb by varying the alignment'between channel 27 and opening :28. A central bore 29in body 26 accommodates a needle valve 30 whose axial position is adjust able by a knob 31wherebythe flow of fuel oil from a supply pipe 32 through bore Z9-into the central orifice 33 of nozzle 13bcan be selectively-throttled; 'Air under pressure, arriving through a pipe34, flows through a similiar regulating valve 35 into a lateral passage 36 of body 26 terminating at'an annular channel 37 of nozzle 13b sur- Way of an-entrance opening 28 in a ring 29'; rotation of the spirit and scope of the invention as defined in the appended claim. i

I claim: I a I v A method of producing a combustible gas, comprising the steps of axially injecting into a generally, cylindrical chamber open at one end,adjacent a closed end of said chamber, an admixture of atomized liquid hydrocarbons with a high-velocity stream of oxidizing gas with a velocity of substantially 50 to SOO me'ters per secondand constituting on the-order of 5 of the stoichiometric quantity of oxygen necessary for complete combustion of said hydrocarbons, thereby creating a spray cone diverging towardesaid open end at an angle .of substantially 10 to 30?, so positioning said cone Within said chamber as to provide a generally toroidal pocket around the-apex of said cone communicating with the, remainder-of said chamber-over substantially its entire transverse cross-sectiontwhile allowingat inosta small clearance between the base of said coneand the inner chamberwallwith conserounding its orifice 33. The resulting spray-15b strikes the wall of tube 11b near its mouth 1722 or passes out- Wardly in'close .iproxirnitygthereto so as to create conditions of turbulence'similar to those previously described; The region of impingement, if any, ofthe spray upon the tube Wall is adjustable as the tube 11b, rotatable within its sleeve 25, isthreadedly securedito a boss 38 of body 26 so, as to be displaceable, relatively thereto in axial direction. v

The gasifiers according to the invention operate in all instances substantially free fromisootand Without traces of glowing particlesin the outer or secondary-stage flame produced thereby. This name springs .up immediately after ignitionji'nthe cold state 'of'the burner, and can be" suitably regulated by the various adjustment means described in connection with FIGS, 1 and 3. The axialex:

tent of the turbulence zone can be very limited, fog. of V the order of 20 mm., withoutinterfering with the ready ignitability of the inner or. first-stage flame. In those cases Where the developinggasis carried ofi 'forcombus f tion elsewhere, ,e.g. as illustrated in FIG. 2, it will-of course be necessary to supplement it with additional air or oxygen at the combustion, site to establish the stoichiometric balance. 1 I v Modifications of the specific structures. described and illustrated are; of course, possible without departure from' quent generation of a vortexfof ignitable mixture from said spray cone within said pocket, :igniting'said mixture whereby" a flame is established in said vortex, admitting "additional oxygen torsaid pocket adjacent the apex :of said cone, and limiting the supply of oxyg'enin said chamber-tosubstantially less than the stoichiometric quantity neededfor'combustionof said hydrocarbons whereby a cornbus'tible'zgas issues from said open end, said spray cone blocking substantially completely the entranceof outside air into saidchamberthrough saidopen end, said oxidizing gas being admitting into saidchamber at a gauge pres- -sure ranging between substantiallyO'fi and 5 atmospheres and providing with saidadditional'oxygen an oxygen sup- -ply in said Chafllbbf' lifl1lted.:t0 approximately of said stoichiometric quantity.'

References :Cited in the file of this patent UNITED lSTATESI'PATENTS' 710,130 I Weiss Sept. 30,1902 945,967 Mahr Jan. 11,.1910 1,199,716 Severs Sept. 26, 1916 1,373,190 Good Mar. 29, 1921 1 1,417,819 'Fuetter Maj '30, 1922 l 1,869,897 'I-Iymer Aug, 2,1932 2,207,010 Hop-kins July 9; 1940 2,515,845 Van den Bussche July 18, 1950 2,675,993 Smith'et a1; Apr. 20, 1954 2,701,608 Johnson 'Feb. 8,1955

, FOREIGN PATENTS 5,715 Great Britain of 1886

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