US2785213A - Method for producing acetylene - Google Patents

Description

March 12, 1957 J. E. BLuDwoR'n-l 2,785,213

METHOD FOR PRonucING ACETYLENE Filed May 4. 1951 4 sheets-sheet 1 wmf.

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March 12, 1957 J. E. BLuDwoRTH METHOD FOR PRODUCING ACETYLENE 4 Sheets-Sheet 2 Filed May 4. 1951 fad I /ENTOK. j. ,f

Much 12, .1957 J, E, BLUDWORTH 2,785,213

METHD FOR PRODUCING ACETYLENE 4 Sheets-Speed; 3

Filed May 4. 1951 March l2, 1957 J. E. BLuDwoFm-x METHOD FOR PRODUCING ACETYLENE 4 Sheets-Sheet 4 Filed May 4, 1951 l I INVENTOR.

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United States Patent METHOD FOR PRODUCING ACETYLENE Joseph E. Bludworth, Corpus Christi, Tex., assignor to Delhi-Taylor Oil Corporation, a corporation of Deiavvare Application May 4, 1951, Serial No. 224,540

9 Claims. (Cl. 260-679) This invention relates to a processv and apparatus for the production of acetylene and more particularly to a process and apparatus for the production of acetylene from hydrocarbons such as methane. In the past it has been proposed to produce acetylene by processes involving the subjection of hydrocarbons such as methane to very high temperature conditions for short periods of time. Such previously employed processes include those in which an electric arc is used to supply the necessary heat for the conversion as well as those processes in which methane is heated in externally red tubes or is passed intermittently over hot refractory materials. However, these processes have not been entirely satisfactory because of the expense involved, low conversion rates and inability to produce a truly continuous process.

This invention has for an object the provision of a continuous process for preparing acetylene from hydrocarbons such as methane in which a portion of the heat necessary for the reaction is supplied by the partial combustion of the hydrocarbon itself.

A further object of this invention is the provision of a readily controllable process in which a hydrocarbon, such as methane, and oxygen are mixed in the relatively cool condition and then preheated to an elevated temperature prior to the time that they are subjected to a partial combustion reaction.

A still further object of this invention is the provision of a process that may be readily controlled to insure that the partial combustion and concomitant production of acetylene occurs in the reactor and not elsewhere in the equipment.

A still further object of this invention is the provision of a process which is carried out in such a manner that a mixture of a hydrocarbon, such as methane, and oxygen may be heated to elevated temperatures before passing to the acetylene-producing reaction section.

A still further object of this invention is the provision of a process and apparatus for heating a mixed stream of oxygen and a hydrocarbon, such as methane, to an elevated temperature without substantial reaction.

A still further object of this invention is the provision of a method of initiating a combustion reaction in a reaction chamber in which acetylene is produced from a hydrocarbon.

A still further object of this invention is the provision of a process and apparatus for preparing acetylenevfrom natural gas.

Further andadditional objects will appear from the following description, the accompanying drawings and the appended claims.

In accordance with one embodiment of this invention, a hydrogen gas, such ask methane, is mixed in a relatively cool condition with oxygen. The cool mixture is then passed at a high linear velocity through a tubular coil furnace whereby the stream is heated to a temperature between about l200 and 2000* F., the linear velocity of the stream being maintained such that combustion of the methane will notoccur Ywithin the tubular heater.

2,785,213 Patented Mar. 12, 1957 Thereafter the preheated mixture is passed through an unobstructed enlarged reactor in which partial combustion of the methane is allowed to occur. This partial combustion results in the consumption of substantially all of the oxygen and simultaneously raises the heat of the reaction mixture to a temperature between about 2000 and about 3000 F., thereby converting the unburned methane to acetylene. The gases undergoing combustion are passed through the reactor at a high linear velocity so that the temperature reached during combustion is only maintained for a very short period, i. e. between about 0.001 and about 0.01 second. Thereafter the hot reacted gases containing substantial amounts of acetylene are quenched and subjected to an acetylene recovery process. As will be more clearly pointed out hereafter, the conditions of the process may be controlled so that the quenched exit gases from the reactor contain in excess of l0 percent by volume of acetylene.

Another aspect of this invention resides in the method and means for preheating a high velocity stream of oxygen and a hydrocarbon under conditions to heat it to a temperature between l200 and 2000" F. under conditions substantially preventing any reaction between the oxygen and methane therein at the prevailing temperatures. ln accordance with one embodiment of this invention, this object is achieved by providing a preheater furnace having a pair of lire chambers separated by two closely spaced refractory walls. A tubular heating coil for the hydrocarbon-oxygen mixture is placed between the two refractory walls annd the latter are heated by suitable burners directing llames against the opposite outside surfaces thereof. Thus the tubular heating coil between the refractory walls is heated solely by radiant heat, thereby insuring even heating substantially throughout the entire length of the coil.

For a more complete understanding of this invention, reference will now be made to the accompanying drawings, wherein Fig. 1 is a liow plan showing in diagrammatic form an apparatus for carrying out the process of this invention;

Fig. 2 is a broken perspective view showing a preheater furnace constructed in accordance with one embodiment of this invention;

Fig. 3 is a vertical sectional view of the preheater furnace shown in Fig. 2 taken along the line 3 3 thereof;

Fig. 4 is a top plan view of the preheater furnace shown in Fig. 2 with a portion being shown in section taken along the line 4 4 of Fig. 3; and

Fig. 5 is a sectional view of one embodiment of a reactor or combustion chamber which may be employed for carrying out the process of this invention and also illustrating means for quenching the hot reaction products.

In carrying out the process of this invention, it is preferred to employ natural gas as the source of methane for the production of the acetylene. Ordinarily dry natural gas may contain about methane and about 5% of ethane and heavier hydrocarbons. Preferably all of the hydrocarbons heavier than methane are removed from the natural gas charged. To this end and with reference to Fig. l, natural gas (suitably containing 95% methane and 5% higher hydrocarbons) is introduced to the apparatus through line 10 into pump l2 wherein it is compressed to between 900 and i000 pounds per square inch whereafter it is passed through line 14 into the lower portion of a conventional absorber i6. Absorber oil, such as kerosene, is passed into the top of the absorber 16 through line 18 and is withdrawn from the absorber through line 20. At the elevated pressure obtaining within the absorber (e. g. 900 to 1000 p. s. i. g.) substantially all of the hydrocarbons heavier than methane are absorbed by the oil and Substantially pure methane I oxygen mixture.

bustion mixture is then quenched at; once upony discharge from the reactor 64. by means of a convergiugwater Spray supplied through a perforated circular ring 72. The temperature of the. gases is thereby immediately reduced to. prevent undesirable side reactions., such as excessive carbon formation and/ or the polymerization of the acetylene. Thereafter the quenched reaction gases are further cooled by passing into a quench tank 74 andvupwardly through a tower 76 into the top of which cooling water is introduced through line 7S. The tower 76 suitably contains Raschig rings to provide an effective cooling area and water is circulated to a cooling tower (not shown) through a line 80 extending from a lower portion of the quench tank. The quenched reaction gases Withdrawn from the tower 76 through line S2 contain essentially hydrogen, carbon monoxide, carbon dioxide, nnreacted methane and acetylene. In order to recover the acetylene,

these gases are pumped by pump Se under pressure Y through line S and the heat exchanger 83 and -a line 90 to an acetylene absorber 92. The acetylene absorber liquid may comprise acetone, acetaldehyde, acetonitrile, nitrobenzene, chlorinated hydrocarbons, polyglycols and their esters, or any of those that are known in the art for absorbing acetylene from gases of this character. The enriched absorber liquid is discharged from absorber 92 through line 94 to a suitable acetylene recovery apparatus (not shown). Tail gases from which substantially all of the acetylene has been removed are withdrawn overhead through line 96 and regenerated absorber liquid is passed to the absorber through a line 9S.

Animportant feature of this invention is the provision of particular type of furnace preheater for the methaneit will be borne in mind that it is preferred, in accordance with the process of this invention as above described, to preheat the oxygen-methane mixture to a temperature between about 1200" F. and about 2000" F. without initiating a combustion reaction. This can be done by employing a preheater furnace of the character di'sciosed in Figs. 2, 3 and 4. This furnace comprises essentially a pair of firingchambers 100 and 102 laterally spaced from each other and separated by a pair of spaced refractory walls 1% and 106 between which is defined a narrow radiant heating chamber S. 'The walls 104 106 are constructed of a highly refractive maaerial such as silicon carbide which will withstand direct firingat temperatures in excess of 3500o F. and which have an extremely high heat transfer rate. The forward endV wall 110. which is common to the tiring chambers 100 and 102 is provided with two vertically spaced rows of apertures M2 through which extend gas pipes or burners E14 connected to a main gas supply 116. These burners impinge against odset bricks 113, thereby directing flames in a horizontal direction along the opposing sides of the refractory Walls 204 and- 106. Products of combustion escape from the chimneys 120 and 122. Thus it will be apparent that the flames do not impinge directly against the preheater coil 52 and local overheating which may cause burning within the tube is thereby avoided. lAlso oxygen of the air does not circulate through the radiant heating chamber in contact with the coil 52. It will be noted from Fig. 4 that the discharge line 62 is wrapped with insulation 124 to prevent heat loss between the pre-- heater and the reactor ed. This insulation material is not indicated in the. drawing of; Fig. l.

It will be apparent from the foregoing description of the apparatus that much equipment not shown in the drawing will be employed in actual commercial practice of this invention. Thus the drawings do not show various meters, valves, heat exchangers and recording instruments, the use of which is well known to those skilled in the art and is contemplated within the scope of this invention.

For a more complete understanding of this invention, reference will now be made to. a speeinc. exempte snowing the manner in which the process of this invention may be Carried. 011t- Ii he appreciated, beweren that this example is not to be construed Vas the broad aspects of the invention herein claimed. Streams of oxygen and methane were mixed in the mixing box 46 without preheating and at ambient temperature (i. e. about 82 E). The methane was fed to the mixing box at the rate of 2,481 standard cubic feet per hour and the oxygen was fed at the rate of 1,301 standard cubic feet per hour. Thus the volume ratio of oxygen to methane was approximately l to 2. This relatively cool mixture was then Y"assed into the line 50 at about 34 pounds per square inch gauge, this pressure being suiicient to force the mixture lat an extremely high linear velocity `through the preheater coil 52. The preheater coil in this example comprised a 2O foot length of 3A inch chrome steel alloy tubing in a fore part of thev furnace (up to juncture 5,9) secured to an 11.7 foot section of 7/s inch chrome. Asteel tubing beyond juncture 59. The coil was serpentine in shape as shown in Fig. 5 and constituted five passes. be.- tween the hot refractory walls 104 and 106. These walls were spaced about 21/2 inches apart forming ,a Barrow radiant heating chamber about 6l/2 Vfeet long and 3.1/2 feet high. The furnace tenlperature` was adjusted and a small amount of charge gas (24 standard cubic feet per hour) was by-passed through valve. 56 so that the outlet temperature of the furnace was controlled to 1750 F. At this temperature substantially no reaction between the methane and oxygen occurred in the furnace, this being at least in part due lto the extremely high velocity of the gases forced therethrough, the pressure of the gases at the discharge end of the preheater being substantially atmospheric. Under these conditions the velocity of the gas entering the preheating furnace was about 142,5 linear feet per secondV andthe velocity of the gas at the outlet end of the preheating furnace wasl about `148,0 linear feet per second. The gaseous mixture heated under these conditions was then passed, as abovel described, directly into a 2 inch silicon carbide (Carbofrax) reactor tube which was about 23S/e inches long and which contained a thermowell with thermocouples, as indicated ,in Fig, 5. The No. 2 thermocouple (T2) was positioned 8 inches from the discharge end of the reactor tube 64j. The silicon carbide electrical resistance elements '7.0 were heated to a suicient temperature to permit partial combustion to be maintained within the reactor tube, the gas velocity from thev discharge end of the reactor tube being about 348v feet per second.

Under the conditions indicated, they combustion occurred in the tube 64 essentially downstream of the point T1 (see Fig, 5), the temperature at this point being about 1900" F. The temperature at point 'I g was 2l50 F. and the temperature at point T3 was 2700 F. (point Ta being about 3 inches from the discharge end of the tube). The average residence time, of the individual gas molecules in the reactor 64 was about 0.0.0813 second While the reaction time (residence time between Tg and the quench) was about 0.00219 second. The combustion gases were immediately quenchedj with the. converging water spray as above described and the acetylene was recovered from the reaction gases through an acetone absorption system. The reaction gases discharged to the quench tower had theY following analysis in volume per cent (dry basis):

"the above indicated analysis, indicates. e Yield et acety- Iene, amounting to 216 standard cubic feather haar on Ving necessary for the acetylene-forming reaction.

.nitrogen or other inert gas into the chamber.

7 the basis of 1000 standard cubic feet per hour of methane vfed to the process. This is the equivalent of 14.8 pounds of acetylene per 1000`standard cubic feet per hour of methane fed to the system.

From the foregoing it is clear that a simple and readily controllable process has beenprovided for preparing acetylene from methane. A particular feature of the invention involves the stepA of mixing the methane and oxygen while in the relatively cool state and thereafter preheating them together to obtain a desired pre-combustion temperature. It has been in the past proposed to preheat either the methane or the oxygen before mixing. However, 4where this has been done, the process has been extremely dificult to control and almostalways the combustion will eventually occur directly at the mixing point, 'resulting in inefiicient'conversion and rapid disintegrationV of the mixing nozzles. A- further feature of the invention is the `passing of the mixture of hydrocarbon gas and oxygen through the preheater at an ex'- tremely high velocity, thus reducing the time factor and permitting a high heat transfer rate in order to prevent undesired combustion from occurring directly within the preheater. If combustion is allowed to occur at this point,y extremely high temperatures will be generated vwhich. will serve to burn out the coils in short order. On the other hand, it is desired that the preheating be carried Yout in a manner to achieve as high a temperature as possible before introducing the preheated stream into the reaction zone. The higher the preheat, the less oxygen -is required in the mixture to supply the autogenous heat- Likewise, less methane is consumed in the combustion reaction leaving more gas for acetylene production. A contributing factor in permitting this high heat to be achieved Y without substantial reaction in tthe preheater is the construction of the preheater furnace itself as previously described. In the modification of the preheater employed inthe specific example given above, the silicon carbide refractory walls were spaced about 2% inches apart and the serpentine coil was spaced therebetween by means of ordinary refractory brick.

In starting up the process, the preheater is tirst fired and the electrical resistance elements of the reactor are turned'on. Pure methane gas with lor without small quantities of oxygen is thenl passed through J'che preheater coil and the reactor until such time as the effluent from the preheater is in excess of about i200" F. and until the Atemperature at point T2 in the reactor has reached about 2100" F. The addition of small amounts of oxygen during the start-up and during the eventual cooling down 'periods seems to increase'the life of the heating coils. Thereafter `additional oxygen is slowly introduced into the system through line 36 until the optimum concentration has been reached at the mixing box 46. As the oxygen is introduced, combustion starts in the reactor to lproduce the desired temperatures. It is important not to allow `the temperature in the reactor to exceed about .3000 F. since the higher temperatures will result in the formation of an undue amount of carbon together with substantial polymerizationrof acetylene. After lthe desired reaction temperature has been obtained, the resistvance elements 70 may `be cut out of the vsystem or the collec-t on theY surface of the heating elements 70 perhaps 'due *to* hydrocarbon gases diffusing into the chamber surrounding the reaction tube VV6,4.

This diiiiculty was eliminated by continuouslyintroducinga small stream of Other means than the electrical resistance elements 70 may be used 'to impart external heat to the reactor 64, however,

"electrical resistance heatingv is one of the vfew methods' *capable ofireachingsudiciendy high temperatures neces` the reactor.

V8 sary to overcome heat loss. in the apparatus shown when operating in the range of 2500" to 3000* F.

As indicated inthe foregoing, it is preferable that the exit gases from the preheater have a temperature between about 1200 and 2000`iF. and a feature of this invention resides in the discovery that under controlled conditions a mixture of methane and oxygen may be heated to these high temperatures without reacting.

yBest results have been achieved, however, Where the preheat temperature is between about 1600 and 1900 P. Likewise, as suggested above, the'combustion temperature should be between about 2000" and 3000 Apparently rthe acetylene reaction begins just at about 2000 F. but carbon formation begins to take over at the temperatures above 3000 F. Temperatures that have been found most suitable for the reactor are within the range of 2600 to 2950" F.

if desired, an initiator or promoter, such as propane, acetaldehyde, acetone or the like, may be added in small quantities directly to the reactor tube 64 through line 60 (see Fig. l) whereby to assist in controlling the combustion therein. f

In order to avoid polymerization of the acetylene that is formed, it is preferred that the pressure within the reactor be at about atmospheric pressure or even less. Likewise exceedingly short reaction times are important, preferably less than 0.01 of a second, suitably between 0.01 and 0.001 second, longer times being permissible where lower temperatures are employed.

As pointed out in the foregoing, this invention iinds primary application in the production of acetylene from natural gas and particularly from methane. Usually it is preferred to employ substantially pure methane in order that the operations may be stabilized. The presence of other higher hydrocarbons will have a tendency to initiate a combustion reaction in the preheatercoil which is4 undesirable. Also for this reason, the adsorber 24 is employed to prevent higher hydrocarbon materials (e. g. absorber `oil vapors)V from getting into the preheater coil.

\ On the other hand, after the methane-oxygen stream has been preheated to the optimum amount, it may be de sirable under certain conditions to add an initiator, such as acetaldehyde or acetone or a higher hydrocarbon (ethane, propane, etc.), in order to assist the combustion in the reactor 64. l Such Van initiator is useful in starting the combustion reaction and maintaining itin Such an initiator may be added, as suggested above, by means of line 60 directly into the reactor 64 through a suitable opening (not shown) in the end plate 66.

In large scale commercial oper-ations the use of the resistance elements 70 or other heating means may be dispensed with entirely after the reaction has been started since, Where heat losses `are not too rapid, the appropriate temperatures may be maintained by the partial combustion in the reactor. IIt is, of course, readily apparent that heating means, other than electrical resistance elements, may be employed when necessary for the reactor tube 64.

`It will also be understood that the process of this in-V vention, in its broader aspects, Vis applicable to other hydrocarbon gases, such as ethane or propane. However, if such gases are used, either alone or in admixture with methane, lower preheat temperatures than those suggested above may be necessary.

While particular embodiments of this invention are suggested above, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, andv it is contemplated, therefore, by the appended claims, to cover any such modiications as fall within the true spirit and scope ofthis invention. y

'I claim: Y.,

1. Aprocess of producing acetylene from a normally gaseous" hydrocarbon which comprises mixing gaseous 21ans-,a is

streams of oxygen and said hydrocarbon, the amount'of 'oxygen in the resulting mixture being less than that required for the complete combustion of the hydrocarbon, heating the resulting mixture in a iirst elongated coniined stream to a temperature between about 1600 and about 1900 F., said stream moving at a high linear velocity under conditions fo prevent substantial combustion of the hydrocarbon therein, then passing the heated stream through an enlarged reaction zone at a high linear velocity less than the linear velocity of said iirst stream and in the absence of a substantial amount lof free hydrogen separately passed into said zone, partially combusting said mixture in said reaction zone at a temperature in excess of about 2000" F., the average residence time of the molecules undergoing reaction at said last-mentioned temperature being less than about 0.01 second whereby substantial quantities of acetylene are produced, immediately quenching the reacted mixture after said residence time, and separating acetylene from the quenched reaction mixture.

2. A process of producing acetylene from methane which comprises mixing relatively cool gaseous streams of oxygen and methane, the amount of oxygen in the resulting mixture being less than that required for the complete combustion of the methane, passing the resulting cool mixture through an elongated heating coil at a high linear velocity under conditions to prevent substantial combustion of methane therein, heating said mixture in said coil to a temperature between about 1600 yand about 1900" F., maintaining the linear velocity of said mixture through said coil at a value suicient to prevent said substantial combustion of methane, then passing the heated stream through an enlarged reaction zone at a high linear velocity less than the linear velocity of the stream discharged from said coil and in the ab sence of a substantial amount of free hydrogen separately passed into said zone, partially combusting said mixture in said reaction zone at a temperature in excess of about 2000" F., the average residence time of the molecules undergoing reaction at said last mentioned temperature being less than about 0.01 second whereby substantial quantities of acetylene are produced, immediately quenching the reacted mixture after said reaction time has elapsed, and separating acetylene from the quenched reaction mixture.

3. A process of producing acetylene involving the partial combustion of methane which comprises mixing relatively cool streams of oxygen and substantially pure methane, thereafter introducing the mixture at high linear velocity into an elongated externally heated coil, heating the stream in the coil and simultaneously controlling the l'mear velocity of the stream therethrough whereby the temperature of the stream is raised to between about 1600 and 1900 F. and no substantial reaction between the oxygen and the methane is allowed to occur therein, thereafter passing the thus heated stream into an enlarged reaction zone in the absence of a substantial amount of free hydrogen separately passed into said zone, electing a partial combustion of the mixture in said zone at a temperature between about 2000" and about 3000 F., maintaining the average residence time of the molecules at said reaction temperature for a period of between about 0.001 and 0.01 second whereby substantial quantities of acetylene are formed, immediately quenching .the partially combusted mixture after said residence time, and separating acetylene from the quenched mixture.

4.-A process of producing acetylene from natural gas containing methane and higher hydrocarbons which comprises separating substantially pure methane from said higher hydrocarbons, mixing in a relatively cool state a stream of said methane with a stream of oxygen, the amount of oxygen being less than that required to effect a complete combustion of the methane, passing the combined stream through an elongated coil preheater at a high velocity to prevent a combustion reaction within the coil, discharging the substantially unreacted gaseous which comprises passing a relatively cool stream comprising a mixture of a major proportion by volume of methane and a minor proportion by volume of oxygen through an elongated radiantly heated tubular coil whereby the mixture is heated to a temperature between about 1600 and about 1900 F., said stream having a suiciently high linear velocity in said coil to prevent substantial reaction of the oxygen with the methane therein, discharging said heated stream into an enlarged refractory tubular reaction zone through which said gases also pass at a high linear velocity and in the absence of a substantial amount of free hydrogen separately passed into said zone, maintaining combustion of said mixture within said reaction zone whereby the temperature of the gaseous mixture is raised to between about 2600 and about 2950" F., maintaining said last mentioned temperature for a short period of time not exceeding about 0.01 second, thereafter quenching the hot reaction gases, and separating therefrom the acetylene thus produced.

6. A process for the production of acetylene from methane which comprises passing a stream of a mixture of methane and oxygen through an elongated tubular coil positioned between a pair of closely spaced refractory walls, firing opposite outside surfaces oi' said walls whereby said coil is heated externally from opposite sides solely by radiant heat, said stream being heated in said coil to a temperature between about 1600 and about 1900 F., owing said stream through said coil at a high linear velocity sufficient to prevent substantial reaction between the oxygen and the methane within the coil at said temperature, and then passing said stream through an enlarged reaction zone in the absence of a substantial amount of free hydrogen separately passed into said zone to eiect partial combustion of methane and conversion to acetylene.

7. In a process for the production of acetylene by the partial combustion of methane, the steps of passing a mixture of methane and oxygen at a high linear velocity through an elongated tubular coil, heating said tubular coil under high rate of heat transfer conditions solely by radiant heat whereby localized heating of said coil with attendant tendency to develop hot spots therein is substantially prevented, discharging the heated mixture in the substantially unreacted state from said coil at a temperature between about 1600 and about 1900 F. to a reaction zone, and combusting said mixture in said zone in the absence of a substantial amount of free hydrogen separately passed into said zone at a temperature between about 2000 and about 3000 F.

8. A process of producing acetylene involving the partial combustion of methane which comprises mixing relatively cool streams of oxygen and substantially pure methane, thereafter passing the mixture through an elongated externally heated coil, heating the mixture in said coil to a temperature of the order of 1750 F. while maintaining the linear velocity of said mixture through said coil sutiiciently high to prevent substantial reaction between said oxygen and said methane within said coil, thereafter discharging the thus heated mixture at a linear velocity of the order of 1480 feet per second into an enlarged reaction zone and in the absence of a substantial amount of free hydrogen separately passed into said zone eiecting a. part'nal combustion ot the mixture inY saidzoneat a temperature .between about 2600 andY about 2950 F., maintaining the: average, residence time ofthe moleculesf at saidk reaction temperature for a periodrof timeless than about 0.01 second whereby substantial quantities of acetylene `are formed, immediately quenching the partially combusted mixture after said residence time, and separating acetyleney from the quenched mixture.

9. A process of producing acetylene from a narmally gaseous hydrocarbon comprising Vessentially methane which comprisesmixing relatively cool gaseous streams of oxygen and said hydrocarbcui,V the amount of oxygen in the resulting mixture being less than that required for the complete combustion o the hydrocarbon, passing the resulting relatively col mixture'into an elongated heating coilheating` the mixture in said coil by means of exten nallyl applied heat to a temperature between about 1600 and about 1900a F., maintaining Vthe linear velocity of the mixture in said coil suicient to prevent substantial combustion of the hydrocarbon therein, then passing the heated-mixture into an enlarged'reaction zone at a somewhat` reduced high linear velocity in the absence of a substantial` amount of free hydrogen separately passed into said zone, partially combusting said mixture in said reaction zone at a temperature between about 2000 and y about 3000 F., the average residence time of the molequenching fthe reaction mixture, and' separating acetylene therefrom.'

References Cited the tile of this patent' `UN1TED STATES PATENTS 1,272,059- Lacy 'July 9,

V1,940,209 Fischerei al.V Dec. 19,1933 1,965,770 Y BurginV July' 10, 1934 2,030,070 Morrell Feb. v11, 1936 2,195,227 Sachsse' Mar. 26, 1940' 2,196,767` Hasche Apr. 9,1940 2,235,749 Klein et al. Mar. 1,87, 1941 2,236,555. Wulflk Apr'. 1,Y 1941V 2,325,588 Brandt' A-Llg. 3, 1943 2,349,439 Koppers May 23, 1944 2,466,617 Spring Apr. 5, 1949 2,498,444 Orr Feb.Y 21,` 1950 2,541,471 Hull et al. Feb. 13', 1951 2,556,196 Krejci June 12, 1951 2,664,450 Sachsse et al. Dec.,29, 1953l 2,672,488 Jonesv Mar. 16, 1954 2,679,540 Berg May 25, 1954

Claims (1)

1. A PROCESS OF PRODUCING ACETYLENE FROM A NORMALLY GASEOUS HYDROCARBON WHICH COMPRISES MIXING GASEOUS STREAMS OF OXYGEN AND SAID HYDROCARBON, THE AMOUNT OF OXYGEN IN THE RESULTING MIXTURE BEING LESS THAN THAT REQUIRED FOR THE COMPLETE COMBUSTION OF THE HYDROCARBON, HEATING THE RESULTING MIXTURE IN A FIRST ELONGATED CONFINED STREAM TO A TEMPERATURE BETWEEN ABOUT 1600* AND ABOUT 1900* F., SAID STREAM MOVING AT A HIGH LINEAR VELOCITY UNDER CONDITIONS TO PREVENT SUBSTANTIAL COMBUSTION OF THE HYDROCARBON THEREIN, THEN PASSING THE HEATED STREAM THROUGH AN ENLARGED REACTION ZONE AT A HIGH LINEAR VELOCITY LESS THAN THE LINEAR VELOCITY OF SAID FIRST STREAM AND IN THE ABSENCE OF A SUBSTANTIAL AMOUNT OF FREE HYDROGEN SEPARATELY PASSED INTO SAID ZONE, PARTIALLY COMBUSING SAID MIXTURE IN SAID REACTION ZONE AT A TEM-

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