Patented July 10, 1934
v 1,965,770
UNITED STATES PATENT’ OFFICE
1,965,770
PRODUCTION OF ACETYLENE
James Burgin, Oakland, Calif., assignor to Shell
Development Company, San Francisco, Calif.,
a corporation of Delaware
No Drawing. Application October 6, 1931,
Serial No. 567,300
'
17 Claims.‘ (01. 260-170)
This invention relates to the production of oxygen necessary for combustion. For mixtures
containing methane and oxygen, the ratio can
hydrocarbons, ole?ne hydrocarbons, aromatic exceed 1:1, the optimum in a small apparatus
' acetylene from hydrocarbons such as the para?in
hydrocarbons, naphthe?es, natural gas which being substantially 1.321 but increasing with the
5 contains a preponderance of methane, casing
head gas vapors, industrial gases containing hy
size of the apparatus.
_
‘The oxygen fed to the pilot jets can be com
drocarbons and the like. More particularly, the bined with other combustible gases such as hydro
invention is concerned with the incomplete com gen and the like. Since the operation yields‘ hy
bustion of said raw material with oxygen, air or drogen as well as acetylene, it is desirable, from
10 an oxygen-containing gas, the process being exe an economic viewpoint, to recycle the same. The (,5
cuted at or above the ignition temperature of the presence of hydrogen in‘ the reaction mixture
gaseous mixture.
,
favors the yield of acetylene in that it enables
.In cracking methane or other hydrocarbons to the maximum yield to be obtained at a higher
acetylene without the use of oxygen or an oxygen space velocity. These pilot ?ames aid the com
containing gas, great di?iculties are experienced bustion of the gaseous mixture in a closed tube 70
in executing the process due to the fact that the with a relatively small proportion of oxygen which
apparatus employed is of short life under the isnot possible with another kind of oxygen-gas
drastic conditions of pyrogenesis and that coking burner—thus also avoiding the risk of producing _
is more or less ‘unavoidable, entailing great ex
pense in the operation of said method.
an explosive mixture. Gas ?ames with a low oxy
gen: hydrocarbon ratio favor the formation of 15
I have found that when hydrocarbons, natural acetylene. By this arrangement, the heat of
gas or the like are subjected to incomplete com combustion is con?ned in the reaction zone as
bustion with pure oxygen or gases containing the main ?ame burns in an outside atmosphere
oxygen while con?ning the heat of combustion created by the discharged gases of the ?ame.
25 in the reaction zone, relatively high yields of
acetylene are made possible with minimum incon
The gaseous mixture can be burned in any direc- 30
tion, horizontal, vertical, upwards or downwards,
venience and expense. The heat of combustion in various surrounding. media such as hydrocar
can be con?ned in the reaction zone in a variety bons, natural gas, carbon monoxide, carbon diox
of ways depending upon the particular method ide, nitrogen, hydrogen, steam or the like. When
30 selected for incomplete combustion.
the ?ame is burned in a metal tube which sur- 86
For example, an explosive mixture of hydrocar
rounds the ?ame, said tube is preferably cooled
bon and oxygen may be burned in an apparatus by conventional means to prevent the decomposi
as follows: The gaseous mixture exits from the tion of acetylene, due to the catalytic effect of a
burner nozzle at a linear gas velocity above the hot metallic surface.
as respective ?ame velocity of the gas mixture.
When it is desired to dispense with pilot ‘?ames, .0
Due to its gas velocity, the ?ame tends to tear use may be made of a tube into which the gaseous
itself away from the mouth of the burner and mixture is fed. Heat is externally applied to
become extinguished. By maintaining auxiliary the tube to raise the gaseous mixture to its ig
, nozzles adjacent to the main burner nozzle, to nition temperature. Once the reaction is initi
40 whichv auxiliary nozzles is fed pure oxygen, a ated, heat is developed due to the exothermic 05
gaseous mixture containing the same components character of reaction. In the absence of a large
as the main mixture but possessing a greater oxy proportion of nitrogen, the reaction is substan
gen content, or to which is fed a gaseous mixture tially autothermic. Accordingly only such quan- ,
of the same composition ‘as that in the main tity of heat is supplied to the surface of the tube
45 burner-nozzle, the pilot ?ames burning from the as will substantially con?ne the heat of com- 100
auxiliary nozzles maintain ?ame combustion by bustion in the reaction zone, as otherwise the
con?ning the heat of combustion in the immedi ?ame would die out due to the linear gas velocity
ate reaction zone.
The gas mixture emerges being above the respective ?ame velocity of the
from the auxiliary nozzles at a velocity below the gas mixture. The tube may or may not be com
50 respective ?ame velocity of the gas. When pure ,posed of porous or refractory ceramic materials, 105
oxygen is employed, it burns as an inverted ?ame ,'such as quartz, silica, porcelain or alundum, car
in the rest of the gas mixture. In operating in borundum, graphite or the like although due to
the manner described, one is‘ enabled to use a their heat retaining properties it is preferable to
critically lean mixture of hydrocarbon and oxy employ them. However, metals as iron, steel,
55 gen, thereby involving a saving in the amount of copper, brass and the like can also be used with 110
2
1,965,770
advantageous results. The heat supplied to the
tube should be sui?cient to keep the gaseous mix‘
ture ignited in the tube. I have found that de-;
sirable yields of acetylene are realized by the in
complete combustion of the gaseous mixture at
heat of combustion is accumulated in said ma
terial. Subsequently, the explosive reaction mix- ture is passed in the same direction through the
reaction chamber and the con?ned heat of com—
bustion is utilized to support the reaction. The
80
temperatures above 850° 0., preferably at about reaction zone will wander in the manner de
1000° C. or higher. It is preferable that the in scribed previously. When it has reached the end
‘side diameter of the tube be relatively small.
of the reaction chamber, the ?ow of the reaction
The time of exposure of the gases to the high mixture is stopped and the refractory material is
10 temperature a?ects the yield of acetylene. When again internally heated by the combustion of a 85
the temperature of the tube is raised, the space fuel with air, the direction of the ?ow of- heating
velocity may be correspondingly increased in or gas ‘being now opposite to that of heretofore.
der to obtain the maximum yield of acetylene. . After the desired temperature is reached, the
Hydrogen as well as otherin?ammable gases heating is discontinued and the reaction mixture
15 may be added to thehydrocarbon-oxygen mix is again passed through the ‘hot refractory ma
ture for burning, in the main ?ame in order 'to terial, this time in the direction opposite to that
increase the speed of the ?ame propagation. employed in the ?rst period. The direction of
The hydrogen may be obtained from any source operation is thus intermittently reversible with
and may even be utilized as a by-product of the lean oxygen mixtures ‘as with substantially rich
20 pyrolytic conversion. ‘ .
oxygen mixtures, the. only difference being that 95
'
If desired, the gaseous mixture may be‘ burned in the former the ?ow ofthe explosive reaction
mixture is intermittently discontinued while heat
ture such as quartz, silica, porcelain, pumice‘, ing- of the refractory material is being brought
alundum or the, like, to facilitate heat transfer about. Instead of the internal application of heat,
in a tube containing material of a refractory na
to the gas. The refractory material may be uti use may be made of the intermittent external
lized in any form as granular packing, bundles application of heat.
Still ‘another modi?cation may be availed of in
of parallel tubes, or may exist as one piece hav
ing channels, slots or annular spaces. It is pref the general application of the process. The re
erable to employ such refractory tubes with rela action zone may be heated by conducting the
tively small inside diameters. The material is ef?uent gases back through channels adjacent to
heated to a temperature suitable to initiate the the reaction zone thus con?ning the heat to the
ignition‘of the gaseous'mixture. Due to the exo reaction zone by contercurrent heat exchange.
thermic character of the oxidation reaction, The reaction zone may or may not be packed with
su?icient heat is involved to maintain the burn refractory material, although it is preferable in
.
ing of the gaseous mixture despite the fact that the former state.
My invention is not restricted to the use of
the gas is introduced into the tube at a linear
velocity greater than the respective ?ame velocity normally gaseous hydrocarbons nor to mixtures
of thegas mixture. Where a gaseous mixture of of the same as it can be utilized with liquid hydro
hydrocarbon and oxygen is ?owed at a gas veloc carbons which have been ?rst vaporized by any
40 ity greater than the velocity of the free ?ame, suitable means. Further, gases resulting from the
the interpositicning of a refractory material in destructive distillation of coal and the like can
the path of said gas ?ow will cause the mainte be used to advantage in my process, the presence
nance of said ?ame due to the surface action of of inflammable gases increasing the speed of the
the refractory material in speeding up the veloc ?ame propagation, whereas the presence of inert
45 ity of combustion.
gas such as described heretofore enhances the
~
As the reaction proceeds without the further economy of the process.
If desired, control on the speed of propagation
external application of heat, the reaction zones
tend to wander awayfrom the burner-nozzle of the ?ame may be affected through the use of
when the velocity of combustion of the gaseous an electrical ?eld maintained in the reaction zone.
By way of illustration only reference will be
mixture on the surface of the refractory mate
rial is less than the gas velocity. Where the ex had to certain examples of my procedure.
(1) Through a quartz tube of 4.3 mm. and a
plosive mixture is employed, no harm is caused
by such phenomenon, as the gaseous mixture is heating length of 30 cm., a gas mixture of 56%
introduced at the other end of the tube when CH4 and 44% 02 was passed with a velocity of 740
the reaction zone is adjacent thereto. In other cc. per minute at ignition-temperature. A con
words, the direction of operation is intermittent centration of 6.4% C2H2 was found in the e?luent
ly reversible. However, the reaction zone can gas.
(2) Through a silica tube 4.75 mm. diameter
be ?xed by the external application of heat suffi
cient to maintain the heat of combustion in the and a heating length of 68 cm., a natural gas
60 reaction zone or by progressively increasing the oxygen mixture in the ratio 1.4:1 was passed at a
oxygen content in the gaseous mixture, however flow of 8.6 liters per minute. The furnace tem
maintaining at all times a gas velocity greater perature was kept around 1100° C. The e?luent
gas container 10.0% C2H2.
than the ?ame velocity of the gas mixture.‘
(3) A natural gas-oxygen mixture of the ratio
vWhen the process is carried out in a tube packed
25
100
10:;
110
115.
120
125
130
135
with refractory materials, using air, air mixed 1.43:1 and a total gas velocity of 4540 cc. per 140
minute was burned under atmospheric pressure
with the above described burner tip. The sur
oxygen, the heat of reaction for a given gas rounding pyrex tube had a diameter of 1.7 cm.,
volume is restricted and is insu?icient for self was vertical, and the ?ame was directed down
support. Use then can be made of the intermit~ wards. The collected combustion gas contained 1-15
tent heating of the reaction zone by the com a concentration of 6.9% C2H2.
with oxygen or other reaction mixtures contain
ing inert gases instead of substantially pure
bustion of any type of fuel. For example, the
(4) A burner tube nozzle of 5/8" inside diame
e?luent gas from which the acetylene has been ter surrounded by auxiliary nozzles was fed with
scrubbed may be burned in the reaction chamber a mixture of 200 cu. ft. per hour of methane and
packed with refractory material, whereby the 144 cu, ft. per hour of oxygen which was ignited.
1,965,770
3
A concentration of 5.6% acetylene was obtained in ing: burning in an enclosed apparatus a mixture
of gases containing a hydrocarbon and oxygen,
(5) Through "a bundle of 17 alundum tubes the oxygen content being less than half the
(internal diameter 1.5 mm. and length 15 cm.) amount necessary for complete combustion, the
in a quartz tube, a mixture of methane and oxy linear gas velocity being maintained essentially
gen in the ratio of 1.36:1 was passed at a flow of above the respective ?ame velocity of the gas mix
3.6 liters per minute. The reaction after initiation ture in the combustion zone while maintaining
was autothermio. The efiiuent gas contained 8.2% ?ame combustion by conducting it on a surface
of refractory material.
C2H2.
'
4. A method for producing acetylene, compris
Essentially pure carbon monoxide and hydro
10
gen were obtained as by-products of the process as ing: burning in an enclosed apparatus a mixture
the raw material of hydrocarbon character un of gases containing a hydrocarbon and oxygen,
dergoing treatment was substantially decomposed. the oxygen content being less than half the
The e?iuent gas contains, in addition to acetylene, amount necessary for complete combustion, the
15 carbon monoxide and hydrogen approximately in linear gas velocity being maintained essentially
the ratio 1:2 as to constitute a valuable gas for above the respective ?ame velocity of the gas mix
the synthesis of alcohols or for the production of ture in the combustion zone while maintaining
?ame combustion by externally heating the wall
hydrogen.
In these processes, the reaction occurs in a of the ‘reaction chamber.
5. A method for producing acetylene, compris
single state of heating and the gases are pre
the outgoing gas.
420
mixed i. e. mixed before entering the reaction ing: burning in an enclosed apparatus a mixture
zone.
of gases containing a hydrocarbon and oxygen, -
The procedure is applicable at atmospheric and the oxygen content being less than half the
subatmospheric pressures, although at the lat amount necessary for complete combustion, the
25 ter condition, higher yields of acetylene are possi linear gas velocity being maintained essentially 100
above the respective ?ame velocity of the gas mix
A feature not described nor disclosed by the ture in the combustion zone while maintaining
prior art is the incomplete combustion of gaseous ?ame combustion by a pilot ?ame.
ble, in shorter time intervals.
mixtures, using‘ linear gas velocities essentially
6. A method for producing acetylene, compris
30 above the respective ?ame velocity of the gas ing: burning in an enclosed‘ apparatus a mixture
mixture but maintaining a flame combustion by of gases containing a hydrocarbon and oxygen,
suitable means, for example as described hereto the oxygen content being less than half the
fore. For example, by subjecting a mixture of
methane and oxygen to incomplete combustion at
35 a linear gas velocity equal to the flame velocity,
I realized only about 0.7% acetylene in the effluent
gases. Carrying out the process with the identical
mixture with a gas velocity greater than the ?ame
105,
amount necessary for complete combustion, the
linear gas velocity being maintained essentially
above the respective ?ame velocity of the gas 110
mixture in the combustion zone while maintain
ing ?ame combustion by a pilot ?ame whose ?ame
velocity is not less than the gas velocity of the
velocity I was able to obtain a concentration of gas mixture being burned as the pilot ?ame.
7. Same as claim 6 wherein the gas mixtures 115
40 about 6.2% acetylene in the e?iuent gases.
While I have in the foregoing described in some fed to the pilot ?ames contain more oxygen than
detail the preferred embodiment of my invention the main gas jet.
and some variants thereof, it will be understood
8. A method for producing acetylene, compris
that this is only for the purpose of vmaking the ing: burning in an enclosed apparatus a mixture
45 invention more clear and that the invention is not of gases containing a hydrocarbon and oxygen, 120
to be regarded as limited to the details of opera the oxygen content being less than half the
tion described, nor is it dependent upon the sound
amount necessary for complete combustion, the
ness or accuracy of the theories which I have ad linear gas velocity being‘ maintained essentially
vanced as to the reasons for the advantageous above the respective ?ame velocity of the gas mix
50 results attained. On the other hand, the inven ture in the combustion zone while maintaining 125
tion is to be regarded as limited only by the terms ?ame combustion by pilot flames burning from
of the accompanying claims, in which it is my in separate nozzles fed with pure oxygen which burns
tention to claim all novelty inherent therein as as an inverted ?ame in the rest of the gas mixture.
broadly as is possible in view of the prior art.
9. A method for producing acetylene, compris
I claim as my invention:
ing: burning in an enclosed apparatus a mixture 130
1. A method for producing acetylene, compris of gases containing a hydrocarbon and oxygen,
ing: burning in an enclosed apparatus a mixture the oxygen content being less than half the
of gases containing a hydrocarbon and oxygen, amount necessary for complete combustion, the '
the oxygen content being less than half the linear gas velocity being maintained essentially
60 amount necessary for complete combustion, the above the respective ?ame velocity of the gas 136
linear gas velocity being maintained essentially mixture in the combustion zone while maintain
above the respective ?ame velocity of the gas mix ing a ?ame combustion by conducting it on a
ture in the combustion zone, while maintaining refractory surface, allowing the reaction zone to
?ame combustion.
wander from the gas inlet towards ths- gas outlet
2. A method for producing acetylene, compris and then reversing the direction of the gas stream, 140
ing: burning in an enclosed apparatus a mix thus also reversing the direction of wandering of
ture of gases containing a hydrocarbon and oxy
the reaction zone.
gen, the oxygen content being less than half the
10. A method for producing acetylene, compris
amount necessary for complete combustion, the ing: effecting the incomplete combustion of a
linear gas velocity being maintained essentially gaseous mixture of hydrocarbon and oxygen, the 145
above'the respective ?ame velocity of the gas mix oxygen content being less than half the amount
ture in the combustion zone while maintaining necessary for complete combustion, at a tem
?ame combustion by confining the heat of com perature above 850° C., the linear gas velocity
bustion in the reaction zone.
3. A method for producing acetylene, compris exceeding the ?ame velocity of the gas mixture in 150
4
1,966,770
the combustion zone while maintaining ?ame
combustion.
11. A method for producing acetylene, compris»
ing: effecting the incomplete combustion of a.
gaseous mixture of hydrocarbon and oxygen, the
oxygen content being less than half the amount
necessary for complete combustion, at a. temperature above 850° C., the linear gas velocity exceeding the ?ame velocity of the gas mixture in
10 the combustion zone and con?ning the heat of
combustion in the reaction zone while maintain
of hydrogen to incomplete combustion at a tem-:
perature exceeding 1000” C. while con?ning the
heat of combustion in the reaction zone, the linear
gas velocity exceeding the ?ame velocity of the
gas mixture in the combustion zone while main
taining ?ame combustion.
15. A method for producing acetylene which
comprises subjecting to incomplete combustion,
in an enclosed apparatus, hydrocarbon with less
than one-half the amount of oxygen necessary
for completecombustion, the linear gas velocity
ing ?ame combustion.
being essentially above the respective ?ame ve
12. A method for producing acetylene, compris locity of the gas mixture and maintaining ?ame
ing: re?ecting the incomplete combustion of a combustion by conducting the e?luent gases .in
gaseous mixture of hydrocarbon and oxygen, the countercurrent heat exchange to the reaction 90
‘oxygen content being less than half the amount
necessary for complete combustion, at a temper
16. A method for producing acetylene which
ature above 850° C. in the form of surface com
bustion on refractory material, the linear gas
20 velocity exceeding the ?ame velocity of the gas
mixture in the combustion zone and con?ning
the heat of combustion in the reaction zone while
maintaining ?ame combustion.
comprises subjecting to incomplete combustion,
in an enclosed apparatus, hydrocarbon with less
than one-half the amount of oxygen necessary 95
for complete combustion, the linear gas velocity
being maintained essentially above the respective
?ame velocity ofthe gas mixture in the combus
13. A method for producing acetylene, com tion zone while maintaining ?ame combustion,
25 prising: pre-mixing a hydrocarbon and an oxy the ?ame burning in an outside atmosphere cre
gen-containing gas, the oxygen content being less ated by the discharge gases of the ?ame.
than half the amount necessary for complete
17. A method for producing acetylene which
combustion, and subjecting them to incomplete comprises subjecting to incomplete combustion,
combustion at a temperature exceeding, 1000° C.
30 while con?ning the heat of combustion in the
reaction zone, the linear gas velocity exceeding the
?ame velocity of the gas mixture in the combus
tion zone while maintaining ?ame combustion.
14. A method for producing acetylene, com
35 prising: pre-mixing a hydrocarbon and an oxy
in an enclosed apparatus, natural gas with less
than one-half the amount of oxygen necessary 105
for complete combustion at above the ignition
temperature of the gaseous mixture, the linear
gas velocity being maintained essentially above
the respective ?ame velocity of the gaseous mix
ture in the combustion zone while maintaining 110
gen-containing gas, the oxygen content being less ?ame combustion.
than half the amount necessary for complete
combustion, and subjecting them in the presence
JAMES BURGIN.
40
115
45
120
50
12%:
5.5
60
65
130