US2928459A - Annulus type burner assembly with replaceable inner tip - Google Patents

Description

March 15, 1960 DU BOIS EASTMAN ETAL 2,928,459

ANNULUS TYPE BURNER ASSEMBLY WITH REPLACEABLE INNER TIP Filed July 8. 1955 3 Sheets-Sheet 1 QXN b liili N F, 2% A 9% till M D WW I\ QN N NW Q M Wm &

March 1960 DU BOIS EASTMAN ETAL 2,928,459

ANNULUS TYPE BURNER ASSEMBLY WITH REPLACEABLE INNER TIP Filed July 8. 1955 3 Sheets-Sheet 2 T- ia /5 M /7 1 Nb Mardl 1960 DU BOIS EASTMAN ETAL 2,928,459

ANNULUS TYPE BURNER ASSEMBLY WITH REPLACEABLE INNER TIP Filed July 8. 1955 5 Sheets-Sheet 3 QVN QWN mm 1 A a Q NlEwi.

IIIIIIVV/l/l/ll/l/A N \N NW r p F G M WM mm @WM United States Patent@ ANNULUS TYPE BURNER ASSEMBLY WITH REPLACEABLE INNER TIP Du Bois Eastman and William Leon Slater, Whittier,

Calif., assignors to Texaco Inc., a corporation of Delaware Application July 8, 1955, Serial No. 520,871

6 Claims. (Cl. 158-109) This invention relates generally to an apparatus for partial oxidation, synthesis gas generation and is particularly applicable to the generation of carbon monoxide and hydrogen by the partial combustion of a gaseous hydrocarbon with oxygen-enriched air or substantially pure oxygen.

Synthesis gas mixtures consisting essentially of carbon monoxide and hydrogen are important commercially as highly preheated state to reduce the oxygen requirements.

and give a maximum yield of the desired product gas.

For one or more of the foregoing reasons, the prior art burners are characterized by failure of burner elements,

comings of the prior art structures, is simple in construction and is economical in operation. It is another object of invention to provide an improved burner structure which is adaptable for use with various reactants.

Still another object of invention is to provide animprov ed burner structure which is particularly suitable for replacement of burner elements without the sacrifice of a source of hydrogen for hydrogenation reactions and as, I

a source of feed gas for the synthesis of hydrocarbons, oxygen-containing organic compounds, or ammonia.

The partial combustion of a hydrocarbon fuel with oxygen-enriched air or with relatively pure oxygen to produce carbon monoxide and hydrogen presents unique problems not encountered normally in the burner art. It is necessary, for example, to effect very rapid and complete mixing of the reactants, as well as to take special precautions to protect the burner or mixer from overheating.

Because of the reactivity of oxygen with the metal from which a suitable burner may be fabricated, it is extremely important to prevent the burner elements from reaching those temperatures at which their rapid oxidation takes place. In this connection, it is essential that the reaction between the hydrocarbon and oxygen take place entirely outside the burner proper and that localized concentration of combustible mixtures at or near the surfaces of the burner elements is prevented. Even though the reaction takes place beyond the point of discharge from the burner, the burner elements are subjected to heating by radiation from it.

Inadequate mixing results in such concentrations of oxygen in localized areas that relatively complete combustion of a portion of the fuel takes place in these areas, re-

leasing large quantities of heat. In addition, regardless of the type of burner construction employed, eddies of the reactants form combustible mixtures near the burner surfaces. Unless these surfaces are maintained at a temperature below the ignition temperature of the mixtures, they act as flame holders, with the ensuing combustion along the surfaces soon causing overheating and failure of the burner.

Another problem peculiar to this reaction is the tendeney for free carbon to form either on the burner or within the reaction zone, due primarily to inadequate mixing of the gases, leading to burner failure, since formation of carbon on the surface of the burner interferes with the mixing of the gases and causes localized concentrations of oxygen, with resulting overheating of burner elements following its combustion.

With conventional burners, it has been found necessary to use a quantity of oxygen in excess of the theoretical t'o prevent carbon formation. This often causes undesirably high reaction temperatures and increases the problem of cooling the burner. The problem is further aggravated by the fact that in the partial combustion of gases, itis desirable to charge the reactant gases to the b ruerin t taken in connection with the accompanying drawings wherein Fig. 1 is a general illustration of a burner assembly in position;

Fig. 2 is a diagrammatic longitudinal cross secton through the burner tip;

Fig. 3 is a partly diagrammatic longitudinal cross section through the expansion joint of the burner assembly 1 of Fig. 1 taken along line 3-3 of Fig. 6.

Fig. 4 is a cross section through the vburner tip along the line 44 of Fig. 2, without the cooling jacket and showing the replaceable inner conduit in operative position;

Fig. 5 is a view similar to Fig. 4 without the cooling jacket and showing the position of the inner conduit durprior to its locking in ing the assembly of the burner and operative position;

Fig. 6 is an end viewof Fig. 1 looking toward the expansion joint and showing the orientation of the inner conduit whenin operative position;

Fig. 7 is an end view similar to Fig. 6 during assembly; I

and

cross section the assembly of Figs. 2 and 3.

The apparatus of the present invention contemplate the solution to the problem of the lengthy shut-downs of gas generators while burners are being replaced because of the deterioration of burner tips due to the loss of' metal or other burner failure.

Referring to the figures in the drawings, in Figure 1, the burner assembly is indicated generally at A, with the burner tip at B, the expansion joint assembly at C, the mounting flange at D, the hydrocarbon fuel, e.g., natural gas, inlet at E. and the oxygen inlet at F.

In Figure 2, the burner assembly at B is shown in cross section, with the inner conduit, providing the oxygen or anjenriched mixture of oxygen, indicated at 10,

with an outlet therefore at 11 and with diametrically spacedloclringlugs indicated at 12, 12 (see also Figs. 4 and 5). An outer conduit 13, ending in an orifice 14,

is locked in spaced relationship with the inner conduit 10 to define an annular passage indicated at 15 which r leadsto the orifice at 14. Theorifice 14 is surrounded 1 by a cooling jacket indicated at 16, with the arrows in-:

Patented Mar. 15, 1960.

Fig. 8 is a view parallel to that in Fig. 1 illustrating in 3 dicating the direction of circulation of the cooling me-. dium therethrough. The outer conduit 13 carries complementary locking lugs indicated at 17,17 and 18, 18,

which, coact. with. locking lugs 12, 12, -to-.restrain,-.e x tensivel longitudinal. movement. of the inner conduit. Allj the lockinglugs may be integral with. theirrespcctiye conduits or 'welded thereto.

, V 4 r at operating temperature, the nuts are tightened down on the shim by'h'and' and then locked in' place, after which theshims are removed. The burner should operate with the spacing of the shim between the nuts and The outer conduit 13v also. carries apluralityiofl spacer} pins, 19', indicated as 'four in number in theldrawings;

(see Figs. 4 and 5)., whichserveto locatethe, inner-conduit in spaced relationship to the outer conduit. These spacer pins-also may be integral with, the. outer conduit or aflixed, thereto in some other suitable manner.- I

Although a cooling jacketis indicated at 1.6, cooling coils maybeused instead. I

. With: particular; reference to the d sclosures in, Figures {and 5, these show respectively the. positions-ofthg inner conduit. when locked'in assembly, and-duringthe" process of being locked. or unlocked fromathe outenco the lugs, the assembled bolts serving as a safetydevice 7 should the bellows 22 give way.

In, addition to the spacer pins disclosedat 19 and carried by the outer conduit in order to maintain the inner conduit in annular spaced relationship therewith, the

. through the joint..

duit, with two of the spacer pins shown in aligned.posi-:;

tion with. the centers of the locking lugs. Forfglarity of.

disclosure, the cooling jacket has been. omittedgfrom these figures,

' 'Eheapparatus disclosed herein is subjected, to; sever temperature operating: conditions, not'only, being "dis posed adjacent the reaction zone where the synthesis gas; generation proceeds desirably at above 2000 1 and a a frequently as high as 3000 F., but also conveying; re-=- actants which are preheated to relatively .hightemlifiratures, e.g 900 -E., priorto their discharge intothejreac tion" zone. Consequently, structural provision must be made for thehigh diiferential expansion. and contractiom unlocked position, showing the manner in which the alignment we is to. be used, the arrowin 6 (also in Fig. 4) indicating the directionof rotation for unlocking. ,The inner conduit 1i} is removed from the assem-:.

bly by the removal of thefastening means 26 which hold.

. -fi'anges 21 and 'inpo's'ition, and then rotating the con-1 of the several elements of the burner, arising not'only from exposureofthe burner to radiation frorngthehigh temperature reaction zone but also from'the flowof preheated gases. f

It has been determined that the wide-rangeofi tern;

peratul es to which burners of the type disclosed are; ex-

posed contribute greatly to their rapid deterioratiomj not only with respect to metalerosion, but because offthe strains; set up asa result of repeated expansion; and'contract-ion leadingto failure. at the points offjuncture'of the burnerparts. The disclosed structure is found to be. free from the adverse effects of relative expansion iand ontraction f; h several par s because of? the use. ofan expansion. joint.

.=Figure. 3 is an enlarged and. partially sectional view, taken through the line 33 of Figure-'6; showing the expansion joint; assembly indicated at C. This assembly comprises locking flanges .20 and Zlfixed respectively to the outerconduit 13 and inner conduit-110: Th'eFex-. pan'sion joint, includes the. bellows at 22, which, i'ssup- 24z'and 25. The expansion joint, ile, bellows and casing,

is adapted to surroundtheinnerconduit -10 and is joined 'i V to bo'th the inner and outer conduitslby: locking: means duit'to; the position indicated in Fig. 7. In the assem .blyof the, burner toattain the locked position shown in "Fig. 6; thealign'mentrings. are oriented to receive.

the, alignment rod 28, which serves as a preliminary] locking-nieahs before final assembly is made with the nuts, iandbolts 26, Alternatively, the inner conduit 10 may be removed together'with the expansion joint assembly at, Cby removal of. the fastening means. 26 holding flanges 20 and 24 inassembled position.

As show n in Figs. 4 and 5,the locking-lugs are ap proximately- .45 in circumferential extent and may vary to. a maximum of 90.. However, the smaller 'arc is I desirable in order to prevent any shadow effect on the flow of the reactant in the outer. annular conduit, due to .the restriction of'the lugs.

Thus, even though burner from temperature and corrosive influences ,is present under normal burner operating conditions,-the most rapid deterioration. of burner tip metal may be'confined tothe- 1 opening of; the inner.;,conduit by feeding the oxygen or oxygenrenrichedair throughit, so that easily replaceabl nozzles which protect other tip surfaces fromoxygfin and,

the primary flame, are asoluti'on to the problem. The- 'lifelof. the outer tip of the burner has been-increased ported by casing 23, to which are affixed locking flanges? such: as riuts and bolts indicated at '26, which a'reused. to'fasten the adjoining locking flanges to each othertf" Gasket means, e.g. van O-ring, for sealing the casing to,

.In addition to the lock nuts and bolts at 26f'the the conduits are indicated at 27.

locking' flanges each carry an alignment ring indicated a respectively at 20a, 21a, 24a and 25a, which receive the alignment rod 28, the purpose for which will be described 7 below.

The locking fianges24, 25 carried by theicas'ing 23 W also includea plurality of lugs, shown as three each in T number and indicated'respectively as 241) andZSb', to.

. receive spacer bolts and nuts indicated" at 29 and which by the-useof the are assembled on the expansion joint shim indicated in dotted outline.

In'theassernbly of this jointythe burners'arebr'ought upfto operating temperature and the spacer bolts 29} areainsertedy through openings in the 'lugs,; with 'shims inid'tidzbetween. the lugs and nuts: With the burner.

so much by putting the fuel through the annular passage;

and coiling the outer tip, that the inner tip life is the controlling factor now in burner operation. Therefore, 1 when, operating conditions, require that the burner he changed, the, inner'conduit may be replaced and a newi burnert ip iinstalledwithout the inconvenienceand ex pense of: replacing an entire) new assembly, such as] indicated at A; r a

Eurther, because of the difierences in the velocities; required for the satisfactory provision of different fuels the, sizes of, the innerconduitgand the annular passage it defines with 'the outer conduit vary. By appropriate selection ofya suitable size for the outer conduit and the use of :a replaceable inner conduit having a tip with a configurationmost suitable for the fuel to be employedh.

thesame burner assembly and outer conduit can-be used, for both liquid andgaseous. fuels.

The locking flange indicated at {Although as setjforth'above may lqle made {without departing from the spirit and scopethereoflonly such limitations should be imposed as are "indicated in the appended 1 claims.

Weclaimr '1. A-burner structure for-synthesis gas generation; by

the oxidation of agaseous' hydrocarbon coma tip deterioration arising.

a D is used to position the burnerifor operation through. thestructure' in which Y the burner isto operate,but s inceit is-not part oftheinvention, nofurther description of the same will be made.

s d d. variat on f he iuventiQn.

prising an outer conduit and an inner conduit and means for supplying a gaseous hydrocarbon and an oxygenic gas thereto, said inner conduit being replaceable and locked in spaced longitudinal and radial relationship with respect to said outer conduit, said conduits ending adjacent each other to define a burner tip, spacing means on the interior surface of said outer conduit adjacent said tip for defining an annular passage between said conduits comprising a plurality of pins, means for locking said conduits against longitudinal movementcomprising diametrically spaced lugs on the exterior surface of said inner conduit and matched pairs of longitudinally spaced lugs on the interior surface of said outer conduit for cooperating with the lugs carried by said inner conduit, said lugs on said conduits being less than a quadrant in extent and being aligned on centers with pins diametrically opposed to each other to limit the flow restriction of said annular passage, and means for compensating for the differential expansion between said inner and outer conduits comprising an expansion joint, said expansion joint including a casing and a bellowssupported thereby and adapted to encircle said inner conduit, said casing including flanges at each end thereof, said inner and outer conduits having flanges adjacent said expansion joint for assembly in locked position with corresponding flanges of said expansion joint and means for locking said flanges together, said locking flanges each including a substantially ring-shaped. extension, and a member for insertion through the extensions upon their axial alignment when said inner and outer conduits are assembled in locked relationship against longitudinal movement, and radial spacing means carried by said inner conduit member located adjacent but exterior said expansion joint when in assembled relationship therewith and upstream the inlet of one of the reactants and comprising an annulus fixed to said inner conduit.

2. A burner tip assembly comprising the combination of a separate inner conduit member, a separate outer conduit member and spacing means located between and in contact with the conduit members forannularly locating said inner conduit member within said outer conduit member, thereby to define an. annular passage therewith, said inner conduit member ending in an opening and said outer conduit member ending in an orifice in spaced relationship to said opening of said inner conduit member thereby defining a burner tip, said conduit members each having locking lugs adjacent said opening and said orifice thereof for interlocking assembly with each other to prevent axial movement in either longitudinal direction with respect to each other adjacent said burner tip, said burner tip assembly including flexible closure means for said annular passage joined to said conduit members and located in distantly spaced relationship from said locking lugs to accommodate differential expansion between said conduit members.

3. A burner structure for operation at elevated temperatures comprising an outer conduit ending in an orifice, a removable inner conduit located in spaced relationship therewith and ending in an opening adjacent said orifice to define a burner tip therewith, means for locking said conduits against longitudinal movement in either axial direction with respect to each other at said burner tip comprising complementary locking lugs carried by each of said conduits, means between and in contact 6 with said conduits for locating the same in spaced relationship to each other to define an annular passage, and means for compensating for the differential expansion of said conduits during operation of said burner structure fastened thereto, the means for locating said conduits in annular spaced relationship comprising a first means joined to one of said conduits adjacent said locking lugs thereon and a second means joined to one of said conduits adjacent said means for compensating for the differential expansion of said conduits, said outer conduit having means for cooling adjacent said orifice.

4. In the burner structure as set forth in claim 3, said means for compensating for the diflerential expansion of said conduits comprising an expansion joint fastened at its respective ends to said inner and outer conduits, said joint including a bellows and a supporting casing adapted to surround said inner conduit, said casing having locking flanges at the ends thereof for fastening respectively to said inner and outer conduits, said conduits having corresponding locking flanges to which the casing locking flanges are fastened, the locking flanges on said locking flanges on said casing of said expansion joint and on said inner and outer conduits having means to insure' the alignment of said conduits in correct assembled position comprising alignment rings which are oriented in line when said inner conduit in said outer conduit is in position locked against longitudinal movement, and an alignment pin adapted to be inserted through said alignment rings in preliminary locked position of said conduits, and means for fastening adjoining locking flanges to each other. i

6. In the burner structure as defined in claim 1, cooling means carried by said outer conduit at the orifice thereof and surrounding said burner tip and having coolant providing means therefor upstream of said orifice.

References Cited in the file of this patent UNITED STATES PATENTS Germany Aug. 27, 1951 Clarke Feb. 13, 1912 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0a 2 928 459 March 15 1960 du Bois Eastman et a1.a

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 11 for "spaced" read spacer line 4L9 for "coiling" read cooling =9 Signed and sealed this 30th day of August 1960.

(SEAL) Attest:

ERNEST W, SWIDER ROBERT C. WATSON Attesting Oflicer Commissioner of Patents

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