US1965771A

US1965771A - Manufacture of acetylene

Info

Publication number: US1965771A
Application number: US667597A
Authority: US
Inventors: Groll Herbert Peter Augustus; Burgin James
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-04-24
Filing date: 1933-04-24
Publication date: 1934-07-10
Anticipated expiration: 1951-07-10

Description

v Hydrocarbon July 10, 1934- H. P. A. GROLL ET AL 1,955,771

MANUFACTURE OF ACETYLENE F/amc 77p, 6

Oxy; en ase of H12/77 A, 2 C

F/dme 77,0

gli

July 10, 1934. H. P. A. GROLL ET Al. 1,965,771

MANUFACTUBE oF ACETYLENE FiledApIil 24, 1933 2 Sheets-Sheet 2 /7 y draad/*bon Hydro cof-bon 043/9 ef; g 0x y gen ,5y me AW Patented July 1o, 1934 UNITED STATES monomer. or AcE'rrLENE Herbert Fetal-Augustus Groll and Jam Oakland, Calif.

vApplication April 24, 1933, Serial No. 667,159? f l2 Claims. (Cl. 260-170) In a copending application, Serial No. 567,300, led October `6, 1931 by James Burg'in, is described the production of acetylene by the incomplete combustion of mixtures of hydrocarbon and oxygen by an gas velocity greater than the velocity of llame propagation. We have discovered that we can produce at least as good yields of acetylene from gaseous mixtures possessing an gas velocity less-than, equal to or greater than the flame velocity by utilizing a portion .of the llame proper to maintain llame combustion.

, Hydrocarbons such as parailine hydrocarbons, olenne hydrocarbons, aromatic hydrocarbons, naphthenes, natural gas, casinghead gas vapors, industrial gases containing hydrocarbons, etc. are subjected to incomplete combustion with oxygen, air or an oxygen-containing gas at or above the ignition temperature of the gaseous mixture, while maintaining ilame combustion.

While the initial gas velocity may be equal to, less than or greaterv than the ame velocity, the gas velocity is always greater than the ame velocity during the main production of acetylene and during this period flame combustion is main-- tained in an enclosed apparatus by using part of the flame proper. In other words, we provide a comparatively small section of flame at the base in which the gas velocity does not exceed the llame velocity. This portion allows the maintenance of a flame although the main portion of the combustion takes place in a section of a chamber in which the gas velocity is essentially ,higher `than the flame velocity of the mixture. There are several arrangements possible which create a slower gas velocity in a portion of the combustion space situated at the base of the ame and reference will be had to the embodiments illustrated in the drawings merely to supplement the description in the speciilcation. 1

Figures I, II, and III illustrate views partly in section, and partly in elevation of various arrangements adapted to carry out the process, while v Figures IV, V, VI, and VII illustrate ows and shapes of burning gas mixtures in sectional elevation.

Where the initial gas velocity is less than, or

equal to the flame velocity, it is desirable to in crease the gas velocity after the gaseous mixture has been ignited, at the same time maintaining flame combustion in the enclosed apparatus. This condition can be attained by constricting the volume of the gaseous mixture. Conning the ame to a smaller volume serves to concentrate the evolved heat and raises the .concentration of acetylene.

Figure I illustrates a simple arrangement. A combustion chamber consists of one wide.section 1 and one narrow section 2. The b urner face 3 is 60 situated in the wide section and a llame 4 burns from the burner face which is made of metal screen or consists of a great number of small nozzles, or otherwise is designed so that the ilame cannot backfire into the gas device 5.

Thisflame, if allowed to burn to completion in a long enough section ofythe same width as the flame base, would assume the well-known conelike flame shape, as for instance, can be observed on a Fischer laboratory burner. However, inthe .70

apparatus used to carry our invention into practice, the wide portion ofthev combustion space extends, preferably, only for such a distance as to allow the ame to become well started without flickering or being torn away from the burner.

After this distance, the combustion space is narrowed down to a channel, tube, slot or the like. In this constriction, the gas velocity exceeds the flame velocity of the gas mixture and the flame is drawn out in the constriction to a long narrow needle or sheet-liketip as indicated at 6 in the gure. This constriction serves a twofold purpose in that it contines the flame to a smaller volume, thus increasing the flame temperature in the propagation regionand it alters multitude or plurality of channels, tubes or slots 2a. 'I'his gure illustrates that the shape of the reaction chamber or combustionspace can be varied to suit the particular operating conditions. In this iigure, streamline modiilcations of the reaction chambers are shown. The stream-line effect minimizes carbon deposition. The eluent gases containing acetylene arewithdrawn through manifold 8 or may be withdrawn independently from each restricted reaction chamber.

Figure III refers to an apparatus that may be resorted to when the gas velocity'is not greater than the name velocity. Instead of resorting to a screen to prevent backring of the flame into the gas mixing device (not shown), a plurality of small nozzles 9 are provided in the burner 10, 105

the nozzles being arranged in any design throughout the burner so long as there is aifairly large number of the same possessing small internal diameters. In this figure, the burner is shown provided with two concentric rows of nozzles with a bailie 11 located on the face of the burner. 'I'his bale permits of the use of gas velocities approaching the ame velocity, without flickering of the flame, by creatng an expansion space in the combustion chamber 1b under the baille. The constricted portion or reaction chamber 2c contains the needle-like or sheet-like flame previously referred to, the flame velocity being less than the gas velocity due to the restriction in volume of the ignited gaseous mixture. If desired, the mixed gases can be emitted from a screen which contains a baille, the mixing nozzle being located behind said screen. This baffle also serves to keep the base of the flame from getting too close to the screen (when one is used) and destroying the same.

Figures IV, V, VI and V11, inclusive, refer to certain phenomena observed when the initial gas velocity exceeds the flame and one or more baflies are interposed in the gas stream. The premixed gas flows through a channel, tube,

slot

12a, 12b, 12e and 12d or the like where a baille or baiiies 13u, 13b, 13e and 13d are placed at any convenient angles to the gas ow. In the drawings they are shown as being perpendicular to the direction of gas flow. The baille may be placed in the center as 13a and 13b or along the Wall as 13e and 13d or in any otherway. For instance, a series or plurality of bailies may be so located that some are placed along the wall and some away from the wall and nearer the center of the gas flow. 'I'he gas mixture passes through the

channels

12a, 12b, 12e and 12d at a velocity exceeding the ame velocity of the mixture. Figures IV and VI show how the gas stream is distorted and on the downstream side eddies develop by the influence of the baffle or baffles. Figures V and VII show the shapes of flames as they appear when the gas mixture is ignited. 'I'hese flames keep burning by virtue of the local retarding effect of the eddies on the gas stream. As in Figures I, I1 and III, the main part of the ame combustion occurs in a chamber in which thel linear gas velocity exceeds the flame velocity and in each figure is shown a part of the flame proper serving to maintain flame combustion.

The combination of a burner baille with a constricted reaction chamber can be utilized also with a gaseous mixture possessing an initial gas velocity greater than the flame velocity. The reason for this is as follows: 'Ihe flame emerges from the burner which the gas leaves at a velocity exceeding the llame velocity. Two different parts of the flame can be distinguished. The core of the flame which we call the primary flame is maintained by the retarding effect of the baille; It is of red-yellow appearance. A secondary flame skirt surrounding the primary flame appearsat a sharply limited dstance from the burner face. This secondary flame of a blue-red color initiates at the point at which the linear gas velocity by lateral expansion of the gas stream becomes exactly equal to the flame velocity. As the flame is enclosed in a tube or chamber, the secondary llame skirt is much smaller in size than if it were unconned. The greater part of the flame burns at a gas velocity exceeding the flame velocity. By suitably constricting the confining means, the secondary flame skirt can be caused to disappear completely. It is desirable to operate in the absence of the secondary llame skirt as higher yields of acetylene resultI thereby. It is our belief that the greatest formation of acetylene takes place in the red-yellow primary flame, especially in its narrow drawn-out part which is burning at a gas velocity exceeding the flame velocity. The secondary flame skirts 14a and 14h in Figures V and VII also can be caused to disappear by constricting the enveloping unit as in Figure III.

Where a constriction is resorted to, the height of the burner face above the constriction is conveniently made adjustable for different gas mixtures and throughput rates. A faster gas flow or a less explosive mixture naturally needs a larger space for the flame base otherwise the flame, having too small a base, ls blown out of the apparatus.

The gas mixtures are prepared in suitable mixing nozzles and fed to the burner. Where desired, a manifold is utilized to provide an even distribution of the gas inside the burner. The exit gas-from the burner may be cooled with water and passed on to a Cottrell precipitator where it is freed from soot formed as a by-product. While most of the carbon is carried from the reaction chamber or chambers by the gas stream and collected in a cooler and in the Cottrell purifier, a small amount is deposited on the walls of the reaction chambers. This carbon is the easier removable, the more inert gas, as nitrogen and the like, is present in the gas mixture. Where nitrogen is used, the carbon formed is softer and easier removable than the carbon formed using pure or substantially pure oxygen. In order to remove this deposit one or more Scrapers may be provided which scrapes the carbon off the walls of the chamber when operated manually or automatically at predetermined periods.

In order to facilitate the removal of carbon, be it carried away by the gas or scraped from the walls, the flame or flames is or are conveniently arranged to burn vertically downwards as shown in the drawings, although the yield of acetylene is not affected by the vertical (upwards or downwards) or horizontal position of the flame.

'Ihe gas mixture, oxygen-containing gas or hydrocarbon-containing gas can be combined with other combustible gases such as hydrogen and the like. Since the operation yields hydrogen as well as acetylene, it is desirable, from an economic viewpoint, to recycle the same.` 'I'he presence of hydrogen in the reaction mixture favors the yield of acetylene in that it enables the maximum yield to be obtained at a higher space velocity.

Gas flames with a low oxygemhydrocarbon ratio favor the formation of acetylene. We have found it desirable to operate with a gaseous mixture comprising hydrocarbon and oxygen, the oxygen content being less than half the amount necessary for complete combustion of the hydrocarbon present.

As in the copending application, Serial No. 567,300, the heat of combustion is confined in the reaction zone as the ame burns in an outside atmosphere created by the discharged gases of the flame. The various surrounding media may comprise hydrocarbons, natural gas, carbon monoxide, carbon dioxide, nitrogen, hydrogen or the like.

The invention is not restricted to the use of normally gaseous hydrocarbons nor to mixtures of the same, as it can be utilized with liquid hydrocarbons which have been first vaporized by any suitable means. Further, gases resulting from the destructive distillation of coal, cracked gases, by-product methane from coke-oven gas some detail the preferred embodiment of our infractionation, hydrogenation by-product gas, etc. can be used to advantage; the presence of inflammable gases increases the speed of the flame propagation, whereas the presence of inert gas enhances the economy of the process.

If desired, control on the speed of propagation of the flame may be effected through the use of an electrical field maintained in the reaction zone. f

By way of illustration only, reference will be had to certain examples of our procedure.

Example I The apparatus shown in Figure III was used. The flow of gases to the mixing nozzle (not shown) was 2.5 liters per minute of California natural gas and 1.92 liters per minute oxygen (ratio CH4/O2=1.30) 'I'he resulting gas had the following composition:

, Percent C202 7.8 CO2 4.0 CO 31.2 Hz 52.0 Olenes (02H4) 1.0 CH4 4.0

Example II The burner possessed a baffle in the burner face and the flame was enclosed in a tube of uniform diameter. A mixture of 2.5 liters natural gas per minute and 1.91 liters oxygen per minute (ratio CH4/O2=1.30) was fed to the burner. The resulting gas contained 6.4% C2H2.

Example III A slot-shaped apparatus of stainless steel similar to that shown in Figure I was used. A mixture of oxygen and natural gas (ratio CH4/O2=1.315) was introduced into the burner at a rate of 55 liters per minute. The resulting gas contained 7.2% C2H2.

Example IV The apparatus shown in Figure I was used. A mixture of 92.5 ft.3 natural gas and 87.5 ft.3 oxygen-containing gas per hour (76% O2 and 24% N2) was burned in the chambers (ratio CH4/O2=1.39). After cooling .to atmospheric temperature, an 18.5% expansion of the exit gas over the intake was observed. The composition of the exit gas was as follows:

Per cent C2H2 6.6 CO2 4.4 CO 26.0 H2 44.5 Olenes 1.3 Paranes 7.6 N2 9.6

vention and some variants thereof, it will be understood that this is-only for the purpose of making the invention more clear and that the invention is not to be regarded as limited to the details of operation described, nor is it dependent upon the soundness or accuracy of the theories which we have advanced as to the reasons for the advantageousresults attained. On the other hand, the invention is toA be regarded as limited only by the terms of the accompanying claims, in which it is our intention to claim all novelty inherent therein as broadly as is possible in view of the prior art.

We claim as our invention:

1. A method' of producing acetylene which comprises subjecting a gaseous mixture containing hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus, causing at least part of the gaseous mixture to flow at a linear gas velocity not greater than the flame velocity of the gaseous mixture thereby initiating flame combustion and subsequently increasing the linear gas velocity to exceed the flame velocity throughout at least the greater part of the flame While maintaining flame combustion.

2. A method of producing acetylene which comprises subjecting a gaseous mixture containing hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus, the oxygen content being less than half the amount necessary for complete combustion, causing at least part of the gaseous mixture to flow at a linear gas velocity not greater than the flame velocity of the gaseous mixture thereby initiating flame combustion and subsequently increasing the linear gas velocity to exceed the flame velocity throughout at least the greater part of the flame While maintaining flame combustion.

3. A method of producing acetylene which comprises subjecting a gaseous mixture containing hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus at a linear gas velocity not greater than the flame velocity of the gaseous mixture and subsequently increasing the linear gas velocity to exceed the flame velocity throughout at least the greater part of the flame while maintaining flame combustion by part of the llame proper.

4. A method of producing acetylene which comprises subjecting a gaseous mixture containing hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus, decreasing the initial linear gas Velocity which isv greater than the flame velocity to one not greater than the flame velocity whereby flame combustion is initiated and using part of the flame proper to maintain flame combustion of the gaseous mixture after said mixture has had its linear gas velocity increased to exceed its flame velocity.

5. A method of producing acetylene which comprises subjecting a gaseous mixture containing .,hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus, the main portion of the combustion taking place at a linear gas velocity greater than the flame velocity, a portion of the flame proper serving to maintain flame combustion.

6. A method of producing acetylene which comprises subjecting a gaseous mixture containing hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus, the linear gas velocity being essentially above the respective flame Velocity of the gaseous mixture throughout at least the greater part of the flame while maintaining flame combustion by part of the llame proper.

7. A method of producing acetylene which comprises flowing a gaseous mixture of hydrocarbon and oxygen, the oxygen content being insuicient for Vcomplete combustion, in an eny closed apparatus at the ignition temperature o! the gaseous mixture and at a linear gas velocity not greater than the fiame velocity and subsequently increasing the linear gas velocity to exceed the flame velocity throughout at least the greater part of the flame While maintaining iiame combustion.

8. A method of producing acetylene which comprises flowing a gaseous mixture of hydrocarbon and oxygen at alinear gas velocity greater than the ame velocity, reducing the gas velocity of part of the gaseous mixture so as not to exceed the flame velocity at the ignition temperature of the gaseous mixture, igniting the gaseous mixture and utilizing the ignited gaseous mixture to maintain .ame combustion of the remainder of the gaseous mixture at a. linear gas velocity greater than the ame Velocity.

` 9. A method of producing acetylene which comprises subjecting a gaseous mixture of hydrocarbon and oxygen to incomplete combustion in an enclosed apparatus at the ignition temperature of the gaseous mixture, subsequently increasing the linear gas velocity to exceed the flame velocity throughout at least the greater drocarbon and oxygen to incomplete combustion in an enclosed apparatus while maintaining the gaseous mixture ignited, the gaseous mixture at the base of the iiame possessing a gas velocity not greater than the ame velocity while the gaseous mixture at least at the tip of the flame possesses a. gas velocity greater than the flame velocity.

11. A method of producing acetylene which comprises establishing and maintaining a iiame combustion region in an enclosed apparatus, wherein a 'gaseous mixture of hydrocarbon and oxygen possesses a gas velocity not greater than the ame velocity and subsequently causing the gas velocity to exceed the ame velocity throughout at leastthe greater part of the flame.

12. A method of producing acetylene which comprises igniting a gaseous mixture of hydrocarbon and oxygen, the oxygen content being less than half the amount necessary for complete combustion, in an enclosed apparatus at a gas velocity not greater than the ame velocity and subsequently confining the flame to a smaller volume.

HERBERT IPETER AUGUSTUS GROLL.

JAMES BURGIN.