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Патент USA US3023853

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March 6, 1962
G. c. GRUBB ETAL
3,023,843
ACETYLENE PURIFICATION
Filed Aug. 5, 195a
NAPHTHA
ABSORBER
\
H‘
2O
____ 3|
-/
’
/
NAPHTHA
l/STRIPPER
Ki?
*L32_@__,-FLASH GAS
NAPHTHA
""
PRE-STRIPPER
47
FRESH
SOLVENT
NAPHTHA
RECOVERY
INVENTORS
Y
B
GEORGE C. GRUBB
WARREN W. WALK
SHAMSHER S.GROVER
17. fl. 4*:
ATTORNEYS
United States Patent 0
1C6
3,023,843
N.Y., assignors to The M. W. Kellogg Company, Jer
sey City. N.J., a corporation of Delaware
Filed Aug. 5, 1958, Ser. No. 753,366
11 Claims. (Cl. 183—115)
Patented Mar. 6, 1962
2
1
ACETYLENE PURIFICATION
George Craig Grubb, New Shrewsbury, N.J., and Warren
W. Wail-r, Irvington, and Shamsher S. Grover, Elrnhurst,
3,023,843
M
It is another object of this invention to provide a
process which prevents the polymerization of acetylene
homologues.
It is another object of this invention to provide an
improved method for removing acetylene homologues
from a gas mixture containing acetylene, and other gase
ous hydrocarbons, hydrogen and carbon oxides.
Various other objects and advantages of the invention
will become apparent from the following detailed descrip
This invention relates to a process for the production 10 tion and discussion.
According to the process of this invention, the above
of acetylene by pyrolysis of a hydrocarbon feed. In one
objects are accomplished by contacting the acetylene con
of its aspects this invention relates to the separation of
taining gas mixture with a heavy naphtha absorbent under
acetylene from the gaseous pyrolysis products. In one of
conditions which favor the absorption of substantially all
its more particular aspects, this invention relates to the
separation of higher acetylenes from an acetylene con 15 of the acetylene homologues together with a minor pro
portion of acetylene. The rich absorbent is passed to a
taining gas.
?rst stripping zone where it is contacted with product gas
The principal commercial process for the preparation
to strip the absorbed acetylene. The absorbent free of
of acetylene involves the pyrolysis of low boiling petro
leum fractions, i.e., light hydrocarbons ranging from nor
mally gaseous hydrocarbons through light naphthas. In
these processes, the hydrocarbon feed is maintained under
closely controlled conditions of temperature, pressure and
absorbed acetylene but containing absorbed acetylene
homologues is passed to a second stripping zone where it
20 is contacted with a product gas to remove remaining ab
sorbed hydrocarbons including non-polymerized acetylene
reaction time to provide a gas mixture containing a recov
homologues. The regenerated absorbent is recycled to the
bulk of the heat necessary for the conversion of the hydro
carbon to desired products. For the conversion of
by contact with a solvent having a suitably low freezing
absorption zone.
erable quantity of acetylene. As indicated, the process is
In carrying out the process of this invention, the crude
applicable to the conversion of normally gaseous hydro 25
acetylene
containing gas, produced by the pyrolysis of a
carbons as well as normally liquid hydrocarbons. In the
hydrocarbon, is ?rst treated to remove carbon, tar and
conversion of normally gaseous hydrocarbons the feed ma
carbon dioxide which are formed during the reaction.
terial, preferably preheated, is combined with a quantity of
After
this preliminary treatment, the acetylene containing
oxygen in an amount suf?cient to oxidize a portion of the
gas is treated to remove water (formed during the reaction
hydrocarbon feed. This oxidation reaction supplies the
liquid hydrocarbons to acetylene, a suitable combustion
gas, such as hydrogen or mixtures of hydrogen with car
bon oxides, and hydrocarbon is burned with oxygen under
conditions conducive to complete oxidation of the com
and picked up during the preliminary puri?cation steps)
point such as acetone, methanol, ethanol, etc. A pre
ferred solvent is methanol. After contact with the solvent,
the gas which is completely saturated with solvent is
cooled to condense out solvent and dissolved water and
bustion gas. The liquid hydrocarbon feed, preferably pre
heated, is injected into the hot combustion gases. Pre
heating of the liquid hydrocarbon feed should be kept
then passed to the naphtha absorption zone.
In the naphtha absorption zone, the acetylene contain
ing gas is contacted with a heavy naphtha having a boiling
ond.
is maintained between about 0.01 and about 10 and
substantially below reaction temperatures in order to 40 range between about 300° F. and about 500° F. The
boiling range of the naphtha is an important factor since
avoid premature reactions.
too low boiling a fraction would result in the volatilization
The pyrolytic conversion of hydrocarbons is an endo
of
the absorbent during subsequent stripping operations
thermic reaction and the distribution of the pyrolysis re
thereby contaminating product streams while too high
action products is determined to a signi?cant extent by the
reaction temperature and the reaction time in addition to 45 boiling a fraction would complicate the separation of
acetylene homologues from the absorbent. The naphtha
the feed composition. Pressure also in?uences product
absorption tower is operated at a temperature between
distribution. As a general rule, high temperatures com
about 60° F. and about —20” F. and preferably between
bined with short reaction times favor the production of
about 10° F. and about —l0° F. Low temperatures are
acetylene whereas lower temperatures and longer reaction
preferred
because of the tendency of acetylene homologues
times favor the production of ethylene. Conditions most 50
to polymerize at high temperatures. Pressure is main
favorable for the production of acetylene involve reaction
tained between about 30 p.s.i.a. and about 200 p.s.i.a.
temperatures between about 1,500° F. and about 3,000“
The L/ V ratio (mols of liquid naphtha per mols of gas)
P. with a reaction time between about .001 and 0.01 sec
Unfortunately, conditions most favorable for the
production of acetylene also tend to favor the production 55 preferably 0.05 to 2. An acetylene containing gas sub_
stantially free of acetylene homologues is removed from
of acetylene homologues, such as methyl acetylene, vinyl
contact with the naphtha absorbent.
acetylene, diacetylene, etc. in quantities sufficiently great
The naphtha absorbent containing acetylene homo
to be objectionable in addition to other pyrolysis gases
logues and as minor proportion of acetylene, is withdrawn
such as hydrogen, carbon monoxide, carbon dioxide and
heavier hydrocarbons. The acetylene homologues are ob 60 from the absorption zone and passed to a stripping zone
where it is contacted with product gas to remove ab
jectionable because they are highly unstable and tend to
sorbed acetylene. The term product gas, as used herein,
polymerize forming highly explosive polymers. Di
means any of the pyrolysis gases such as hydrogen,
acetylene is a particularly hazardous compound which can
methane, ethane, carbon monoxide, carbon dioxide and
not be handled except in very dilute concentrations. Be
cause of the hazards involved, relatively complicated pro 65 steam, singly or in admixture. An inert gas, such as
nitrogen, can be used as stripping gas in place of product
cedures have been developed, employing expensive sol
gas although there is no particular advantage in such
vents, for separating acetylene from its homologues.
substitution and in fact the use of inert gas is in many
It is an object of this invention to provide an improved
instances deterimental since a foreign component, which
process for the preparation of acetylene.
It is another object of this invention to provide an effi 70 must subsequently be removed, is introduced into var
ious product streams. In order to increase the e?iciency
cient process for separating acetylene homologues from
of the process, the stripped acetylene is recycled and
an acetylene containing pyrolysis gas.
3,023,843
3
combined with feed gas.
4
The stripping zone is main
naphtha absorbent, free of acetylene but containing
14 where its temperature is lowered :to —10° F. The
cooled stream is introduced into knock-out drum 15
where condensed methanol containing dissolved water
is separated from the acetylene containing gas. Con
densed methanol is withdrawn from knock-out drum 15
through line 16 and is combined with the bottoms from
drying tower 11 which are withdrawn through line 17.
The combined methanol stream is then recovered by
acetylene homologues, is withdrawn from the ?rst strip
means not shown. Dry acetylene containing gas is with
tained at a temperature between about 0° F. and about
80° F. and a pressure between about 15 p.s.i.a. and
about 100 p.s.i.a. The V/L ratio (mols of stripping gas
per mol of liquid naphtha) is between about 0.01 to
about 1. Under these conditions substantially all of the
absorbed acetylene is stripped from the naphtha. The
ping zone and introduced into a second stripping zone 10 drawn overhead from knock-out drum 15, through line
where it is maintained at a temperature between about
18 and is introduced into absorption column 19 which
100° F. and about 280° F. and a pressure between about
is operated at a bottoms temperature of 0° F. and a
15 p.s.i.a. and about 50 p.s.i.a. The stripping operation
pressure of 69 p.s.i.a. and a top temperature of 2° F.
and 66 p.s.i.a. Approximately 164,840 pounds per hour
about .05 and about 10. Substantially all of the acetylene 15 of heavy naphtha (L/V=1) are introduced into the top
homologues together with other absorbed gases are re
of absorption column 19 through line 20 as discussed
moved from the naphtha absorbent which is then re
more fully below. Approximately 1,087.8 mols per hour
is carried out with a product gas at a V/L ratio between
of acetylene containing gas substantially free of acetylene
cycled to the absorption zone for further use therein.
During the stripping operations to which the naphtha
homologues are withdrawn from absorption column 12
absorbent is subjected, some of the acetylene homologues 20 through line 21 as product. The composition of this gas
‘will polymerize forming a high-boiling material. To
is given below in Table II. (C2H6+ includes C2 to C6
hydrocarbons.)
prevent the build-up of this hazardous high-boiling mate
rial in the naphtha absorber, a portion of the stripped
TABLE II
naphtha from the second stripping zone is continuously
Mols per hour
purged from the recycle stream. In order to minimize 25 H2 ___
__
__
__
378.1
losses of absorbent, this purged stream is preferably
CO
367.4
treated in a third stripping zone maintained at a pres
N2 _
12.0
sure between about 1 p.s.i.a. and about 10 p.s.i.a. and
a temperature between about 200° F. and about 450° F.
Under these conditions a portion of the naphtha is ?ashed 30
and is withdrawn from the stripping zone. The liquid
naphtha is stripped with a product gas, such as steam, to
remove light boiling naphtha which is recycled to the
absorption zone. The bottoms from this third stripping
CH;
__________________________________ __
CO2
________________ _; _______________ __
.12
_________________________________ __
82.58
CZHZ
02H.‘
C2H6+ Total
operation, which contain polymerized acetylene homo 35
logues, is purged from the system.
Referring to the accompanying drawing, which is a
diagrammatic illustration of an acetylene recovery unit,
109.8
129.13
_
__
___...
1,087.8
'
Approximately 168,900 pounds per hour of rich
naphtha absorbent containing 4,065 pounds per hour of
absorbed hydrocarbons are withdrawn from they bottom
of absorber 19 through line 22 at a temperature of 0° F.
about 1,206 mols per hour of a gas stream containing
acetylene obtained by the pyrolysis of a light naphtha 40 This bottoms stream is heated, in heat exchanger 23,
with naphtha feed ?owing through line 20. As a result
of indirect heat exchange, the temperature of the bot
carbon dioxide is introduced, after compression by means
fraction and treated for the removal of carbon, tar and
not shown, through line 10 at a temperature of 100° F.
and a pressure of 74 p.s.i.a. This gas has the composition
given below in Table I.
TABLE I
Feed, mols
C2Ha+ components
per hour
379.1
372. 9
0.1
12. 2
Total __________ -_
9. 42
8. 02
3. 21
23. 08
112. 8
. 81
92. 3
155. 1
66. 2
15. 5
3. 21
6. 55
3. 70
O. 49
1, 206. 2
toms stream in line 22 is increased to 48° F. at which
temperature it is introduced into the top of naphtha pre
45 stripper 24. The pre-stripper is operated at a bottom
pressure of 17.7 p.s.i.a. and a top pressure of 15 p.s.i.a.
In pre-stripper 24 the rich naphtha absorbent is stripped
by counter-current contact with approximately 54.2 mols
per hour of product gas, which is introduced into the
50 stripping column through line 25 (V/L=.05). This gas
contains approximately equimolar amounts of hydrogen
and carbon monoxide (tail gas from an ethylene unit).
Absorbed acetylene, ethylene and other light gases are
Withdrawn from pre-stripper 24 through line 26. The
55 composition of this stream is given below in Table III.
TABLE III
Mols per hour
1. 95
0. 93
I. 55
2. 24
1. 05
Total _________ __
N2
60 H2
66. 2
- '1 Methyl Acetylene.
b Propadiene.
65
From line 10, the gas ?ows into drying tower 11. In
the process of this example, the gas is dried by counter
current contact with a stream of methanol introduced
through line 12. Approximately 501 pounds per hour
0.98
24.56
CO
28.40
CH4
C2H2
C2H4
C2H6+
9.81
9.30
24.50
11.71
1 109.26
1 01', 2,447 pounds per hour.
Because this stream contains acetylene and other valuable
of methanol at a temperature of 100° F. ?ow through 70 product gases, it is compressed to 74 p.s.i.a., by means
line 12 into the drying tower. The pyrolysis gas satu
‘not shown, and combined with the feed stream entering
at line 10. Approximately 167,200 pounds per hour of
rated with methanol vapor is withdrawn from drying
naphtha containing absorbed acetylene homologues are
tower 11 through line 13 at a temperature of 90° F.
withdrawn from the bottom of pre-stripper 24 through
and a pressure of 72 p.s.i.a. The methanol saturated gas
stream ?owing in line 13 passes through heat exchanger 75 line 27 at a temperature of 45° F. This bottom stream
3,023,843
5
where its temperature is increased to 170° F. by heat ex
sure of 2.2 p.s.i.a. Approximately 270 pounds per hour
change with naphtha feed ?owing through line 20. The
of 300 p.s.i.g. stream are introduced into the bottom of
recovery tower 44 through line 45 to strip o?’ light
thus heated stream in line 27 is further heated to a tem
perature of 210° F. by heat exchange with steam in heat
naphtha. Approximately 417 pounds per hour of heavy
naphtha containing absorbed polymerized acetylene hom
exchanger 30 and is introduced into naphtha stripper 31.
Naphtha stripper 31 is maintained at a temperature of
200° F., a bottom pressure of 33 p.s.i.a. and a top pres
sure of 29.4 p.s.i.a.
ologues are Withdrawn from the bottom of tower 44
through line 53. A light naphtha fraction is withdrawn
from tower 44 through line 46, cooled by cooler 47 and
In the operation of naphtha stripper 31 two stripping
introduced into separator 48 at a temperature of 100° F.
and a pressure of 1.7 p.s.i.a. 270 pounds per hour of
condensed water are withdrawn from separator 48 through
gases (total V/L=0.3) are employed because of the
large amount of gas required to operate stripper 31. The
?rst product gas contains some CO2 which interferes with
the e?iciency of naphtha absorption zone. This ?rst
line 49. Approximately 2,554 pounds per hour of recov
ered naphtha are withdrawn from separator 48 through
line 50, repressured by pump 51 and introduced .into
naphtha storage tank 52. Fresh naphtha, having the com
position given in Table VI, is added to tank 52 as needed,
product gas efficiently strips acetylene homologues etc.,
while the second product gas also strips acetylene homo
logues and in addition the undesired C02. The composi
tion of the stripping gases is given below in Table IV.
TABLE IV
through line 54.
N --
Naphtha Solvent 1 (Used for Removal of Higher Acety
lenes and Higher Hydrocarbons)
Line 32,
Line 33,
mols per
hour
mols per
hour
6. 6
Sp. gravity at 15° C./4° C _______ __ 0.786.
Flash point ____________________ __ 114° F. (46° C.).
25 Freezing point __________________ __ —54° C.
101.1
C O _________________________________________ __
5. 6
98.1
G0»
3. 7
__________ ._
OH.
51. 4
29. 3
GQHB‘I' _______________________________________ -_
Aromatic content _______________ .._ 15.5 vol. percent.
3. 2
34. 5
>
TABLE VI
20
Stripping gas
H2.“
6
44. Recovery tower 44 operates at a temperature of
250° F., a bottom pressure of 3.2 p.s.i.a. and a top pres
is pumped, via pump 28, through heat exchanger 29
1. 3
0.7
103.1
232. 4
Bromine No ____________________ _. 1.7.
1 Molecular weight: 151.6.
30
DISTILLATION CURVE
° F.
330.5
341.5
IBP
5%
The naphtha stream introduced, through line 27 to strip
347
per 31 is initially contacted with 103.1 mols per hour 35 10%
355
20%
of product gas introduced through line 32. Approxi
361
30%
mately 232.4 mols per hour of CO2 free product gas are
367.5
40%
introduced through line 33 to the bottom of stripper 31
374
50%
to further strip the naphtha absorbent and to remove
381
absorbed CO2. An overhead containing stripped con 40 60%
390
70%
taminants and naphtha is removed from stripper 31 via
401
80%
line 35, cooled in cooler 36 and introduced into knock
417
90%
out drum 37. Condensed naphtha is removed from the
446
FBP
bottom of knock-out drum 37 through line 38 and is
pumped to the top of stripper 31 by pump 39. A gas
Approximately 3,200 pounds per hour of fresh naphtha
stream having the composition given in Table V is re 45 are withdrawn from tank 52 from line 55, introduced
moved from the top of drum 37 through line 40.
into line 56 containing pump 57. The naphtha ?owing in
line 56 is combined with the regenerated naphtha in line
TABLE V
58. The combined naphtha stream ?ows through line 56,
Mols per
50 at a temperature of 199° F., is heat exchanged in heat ex
021161‘ components
hour
HL“
______________ __
135. 6
103. 7
3. 7
9- 3
80. 5
52. 5
2._ 42
30
1. 75
6. 90
2_ 61
17. 97
386. 0
2. 83
7. 05
3. 43
1.92
. 75
. 49
. 90
changer 29 with the bottoms from pre-stripper 24 to re
duce temperature to 72° F. and is then introduced into
line 20, cooled to 24° F. by heat exchange in heat ex
changer 23 with the bottoms from absorber 19 and ?nally
55 cooled to -——12° F. by heat exchange with liquid am
monia in exchanger 60. This naphtha stream then en
ters the top of absorber 19 as previously discussed.
While this invention has been described with particular
reference to the removal of acetylene homologues, be
60 cause of the hazards involved in the handling of these
materials, it will be apparent from the foregoing descrip
2. 20
tion that the invention also provides for the removal of
1.03
52. 54
3 Methyl Acetylene.
b Propadiene.
65
other objectional CTCG hydrocarbon impurities, both sat_
urated, and unsaturated, including dienes which, although
not hazardous, also tend to polymerize thereby causing
fouling of the equipment.
Various modi?cations and alterations of the process of
Approximately 164,611 pounds per hour of regenerated
this invention will be apparent to those skilled in the art
naphtha is withdrawn from the bottom of stripper 31
and may be used without departing from the scope of the
through line 41. During the stripping operation some of
the heavy acetylenes will polymerize forming a gum. 70 invention.
To prevent the build-up of these hazardous polymerized
acetylene homologues in the recycle naphtha stream, ap
proximately 2,973 pounds per hour of naphtha are with
We claim:
1. A process for separating hydrocarbon impurities in
cluding methyl acetylene from a gas mixture obtained by
the pyrolysis of light hydrocarbons containing said im
drawn from line 41 through line 42, heated to 250° F.
in heat exchanger 43 and introduced into recovery tower 75 purities and acetylene which comprises: contacting said
3,023,843
7
8
gas mixture in an absorption zone with a heavy naphtha
absorbent under suitable conditions to absorb said impuri
to naphtha absorbent mol ratio between about 0.01 and
ties including substantially all of said methyl acetylene
lene without substantial vaporization of said heavy naph
tha absorbent, contacting the bottoms from said ?rst strip
about 1 in a ?rst stripping zone to remove absorbed acety
and a minor amount of acetylene from said gas mixture,
and contacting the bottoms from said absorption zone
with a stripping gas in a stripping zone maintained under
suitable conditions to remove absorbed acetylene without
ping zone with a product gas in a product gas to naph
tha absorbent mol ratio between about 0.05 and about
10 in a second stripping zone to remove absorbed impuri
substantial vaporization of said heavy naphtha absorbent.
ties, withdrawing naphtha absorbent substantially free of
2. A process for separating hydrocarbon impurities in
said impurities from the bottom of said second stripping
cluding methyl acetylene from a gas mixture obtained by 10 zone and recycling at least a portion of said naphtha ab
the pyrolysis of light hydrocarbons containing said impuri
sorbent to said absorption zone.
ties and acetylene which comprises: contacting said gas
mixture in an absorption zone wtih a heavy naphtha ab
6. A process for the separation of hydrocarbon impuri
ties including methyl acetylene and other acetylene homo
sorbent under suitable conditions to absorb said impuri
logues from a gas mixture obtained by the pyrolysis of
ties including substantially all of said methyl acetylene
light hydrocarbons containing said impurities and acety
and a minor amount of acetylene from said gas mixture,
contacting the bottoms from said absorption zone with a
stripping gas in a ?rst stripping zone maintained under
suitable conditions to remove absorbed acetylene without
lene which comprises: contacting said gas mixture in an
absorption zone with a heavy naphtha fraction having a
boiling range between about 300° F. and about 500° F.
at a temperature between about 60° F. and about —20°
F. and a pressure between ‘about 30 p.s.i.a. and about
substantial vaporization of said heavy naphtha absorbent,
contacting the bottoms from said ?rst stripping zone in a
second stripping zone with a stripping gas to remove ab
200 p.s.i.a. thereby absorbing said impurities including
the pyrolysis of light’ hydrocarbons containing said impuri
ties and acetylene which comprises: contacting said gas
bottoms from said absorption zone with a product gas in
a product gas to naphtha absorbent mol ratio between
about 0.01 and about 1 in a ?rst stripping zone maintained
at a temperature between about 0° F. and about 80° F.
and a pressure between about 15 p.s.i.a. and about 100
substantially all of said methyl acetylene and a minor
sorbed hydrocarbon impurities.
amount of acetylene from said gas mixture, withdrawing
3. A process forseparating hydrocarbon impurities in
an acetylene containing gas substantially free of said im
cluding methyl acetylene from a gas mixture obtained by 25 purities from the top of said absorption zone, contacting
mixture in an absorption zone with a heavy naphtha ab
sorbent under suitable conditions to absorb the impurities
including substantially all of said methyl acetylene and
a minor amount of the acetylene from said gas mixture,
contacting the bottoms from said absorption zone with a
stripping gas in a ?rst stripping zone maintained under
suitable conditions to remove absorbed acetylene‘ without
p.s.i.a. to remove absorbed acetylene without substantial
vaporization of said heavy naphtha absorbent, contacting
bottoms from said ?rst stripping zone with a product gas
in a product gas to naphtha absorbent mol ratio between
substantial'vaporization ‘of said heavy naphtha absorbent, 35 about 0.05 and about 10 in a second stripping zone main~
contacting the bottoms from said ?rst stripping zone in a
tained at a temperature between about 100° F. and about
second stripping zone with a stripping gas to remove ab
280° F. and a pressure between about 15 p.s.i.a. and about
sorbed hydrocarbon impurities,v and recycling atleast a
50 p.s.i.a. to remove absorbed impurities, withdrawing
portion of said naphtha absorbent from the bottom of
naphtha absorbent substantially free of said impurities
40 from the bottom of said second stripping zone and re
said second stripping zone to said absorption zone.
4. A process for separating hydrocarbon impurities in
cycling at least a portion of said naphtha absorbent to said
cluding methyl acetylene from a gas mixture obtained by
absorption zone.
the pyrolysis of light hydrocarbons containing the same
and acetylene which comprises: contacting said ‘gas mix
7. A process for the separation of hydrocarbon impuri
ties including methyl acetylene and other acetylene homo
ture in an absorption zone maintained at a temperature 45 logues from a gas mixture obtained by the pyrolysis of
between about 60° F. and about —20° F. and a pressure
light hydrocarbons containing said impurities and acety
between about 30 p.s.i.a. and about 200 p.s.i.a. with a
lene which comprises: contacting said gas mixture in an
absorption zone with a'heavy naphtha fraction having a
boiling range between about 300° F. and about 500° F. at
heavy naphtha absorbent in which said impurities includ
ing substantially all of said methyl acetylene and a minor
amount of acetylene are absorbed, Withdrawing an acety 50 a temperature between about 60° F. and about —20° F. and
a pressure between about 30 p.s.i.a. and about 200 p.s.i.a.
lene containing gas substantially free of said impurities
overhead from said absorption zone, contacting the bot
toms from the absorption zone with a product gas in a
product gas to naphtha absorbent mol ratio between about
thereby absorbing said impurities including substantially
all of said. methyl acetylene and a minor amount of acetyl
ene from said gas mixture, withdrawing an acetylene con
0.01 and about 1 in a ?rst stripping zone to remove ab 55 taining gas substantially free of said impurities from the
sorbed acetylene with substantial vaporization of said
heavy naphtha absorbent, contacting the bottoms from
said ?rst stripping zone with a product gas in a product
gas to naphtha absorbent mol ratio between about 0.05 and
top of said absorption zone, contacting bottoms from said
absorption zone with a pyrolysis product gas in a pyrolysis
product gas to naphtha absorbent mol ratio between about
0.01 and about 1 in a ?rst stripping zone maintained at a
about 10 in 'a second stripping zone to remove said ab 60 temperature between about 0° F. and about 80° F. and a
sorbed hydrocarbon impurities from said naphtha absorb
pressure between about 15 p.s.i.a. and about 100 p.s.i.a. to
ent.
remove absorbed acetylene as an overhead stream sub
5. A process for the separation of hydrocarbon impuri
ties including methyl acetylene and other acetylene homo:
stantially free of vaporized heavy naphtha absorbent, re
lene which comprises: contacting said ‘gas mixture in an
absorption zone with a heavy naphtha fraction having a
boiling range between about 300° F. and about 500° F. at
bent mol ratio between about 0.05 and about 10 in a sec
ond stripping zone maintained at a temperature between
cycling said overhead stream to said absorption zone, con
logues from a gas mixture obtained by the pyrolysis of 65 tacting the bottoms from said ?rst stripping zone with a
light hydrocarbons containing said impurities and acety
pyrolysis product gas in a product gas to naphtha absor
a about 100° F. and about 280° F. and a pressure between
a temperature between about 60° F. and about -—20° F. 70 about 15 p.s.i.a. and about 50 p.s.i.a. to remove absorbed
and a pressure between about 30 p.s.i.a. and’ about 200
impurities, withdrawing naphtha absorbent substantially
p.s.i.a. thereby absorbing said impurities including substan
free of said impurities from the bottom of saidsecond
tially all of said methyl acetylene and a minor amount of
Stripping zone and recycling at least a portion of said
acetylene from said gas mixture, contacting bottoms from
naphtha absorbent to said absorption zone.
the absorption zone with a product gas in a product gas 75
8. In a process for the preparation of acetylene in
8,023,843
which a hydrocarbon is pyrolyzed to produce a gas mix
ture containing acetylene, hydrogen, carbon monoxide
10
zone wherein they are contacted with a pyrolysis product
gas for the removal of absorbed acetylene without substan
and C2-C6 hydrocarbon impurities including methyl acety
lene and other acetylene homologues, the method for sepa
rating said impurities from said gas mixture which com
prises: introducing said gas mixture into an absorption
zone in which said impurities including substantially all
of said methyl acetylene and a minor amount of acetylene
are absorbed in a heavy naphtha absorbent, passing bot
toms from said absorption zone to a ?rst stripping zone
tial vaporization of said heavy naphtha absorbent, the
mol ratio of said product gas to said naphtha absorbent
being between about .01 and about 1, passing bottoms
from said ?rst stripping zone to a second stripping zone
wherein they are contacted with a pyrolysis product gas
in a mol ratio of pyrolysis product gas to naphtha absor
bent between about 0.05 and about 10 to remove ab
sorbed impurities, withdrawing naphtha absorbent sub
stantially free of impurities from the bottom of said sec
ond stripping zone and recycling at least a portion of
said naphtha absorbent to said absorption zone.
tial vaporization of said heavy naphtha absorbent, pass
11. In a process in which a hydrocarbon is pyrolyzed
ing bottoms from said ?rst stripping zone to a second
stripping zone in which they are contacted with a greater 15 to produce a gas mixture containing aceylene, hydrogen,
wherein they are contacted with a pyrolysis product gas
for the removal of absorbed acetylene without substan
quantity of pyrolysis product gas in comparison to the
quantity used in said ?rst stripping zone thereby remov
ing absorbed impurities from said naphtha absorbent.
9. In a process for the preparation of acetylene vin
which a hydrocarbon is pyrolyzed to produce a gas mix
ture containing acetylene, hydrogen, carbon monoxide
and C2-C6 hydrocarbon impurities including methyl acety
lene and other acetylene homologues, the method for sepa
rating said impurities from said gas mixture which com
prises: introducing said gas mixture into an absorption
zone in which said impurities including substantially all of
said methyl acetylene and a minor amount of acetylene
are absorbed in a heavy naphtha absorbent, passing bot
carbon monoxide and C2-C6 hydrocarbon impurities in
cluding methyl acetylene and other acetylene homologues,
the method of separating said impurities from the gas mix
ture which comprises: introducing the gas mixture into an
absorption zone wherein said impurities including substan
tially all of said methyl acetylene and a minor amount of
acetylene are absorbed in a naphtha absorbent having a
boiling range between about 300° F. and about 500° F,
said absorption zone being maintained at a temperature
between about 60° F. and about —20° F. and a pressure
between about 30 p.s.i.av and about 200 p.s.i.a., passing
toms from said absorption zone to a ?rst stripping zone
bottoms from said absorption zone to a ?rst stripping
zone wherein they are contacted with a pyrolysis gas ‘for
the removal of absorbed acetylene without substantial
tial vaporization of said heavy naphtha absorbent, with
between about .01 and about 1, withdrawing acetylene
wherein they are contacted with a pyrolysis product gas 30 vaporization of said heavy naphtha absorbent, the mol
ratio of said product gas to said naphtha absorbent being
for the removal of absorbed acetylene without substan
containing gas overhead from said ?rst stripping zone and
recycling same to said absorption zone, passing bottoms
stripping zone and recycling same to said absorption zone,
passing bottoms from said ?rst stripping zone to a sec 35 from said ?rst stripping zone to a second stripping zone
wherein they are contacted with a pyrolysis product gas
ond stripping zone in which they are contacted with a
drawing said absorbed acetylene overhead irom said ?rst
greater quantity of pyrolysis product gas in comparison to
the quantity used in said ?rst stripping zone thereby re
in a mol ratio of pyrolysis product gas to naphtha absor
bent between about 0.05 and about 10 to remove absorbed
moving absorbed impurities from said naphtha absorbent.
impurities, withdrawing naphtha absorbent substantially
to produce a gas mixture containing acetylene, hydrogen,
ping zone and recycling at least a portion of said naphtha
carbon monoxide and C2-C8 hydrocarbon impurities in
cluding methyl acetylene and other acetylene homologues,
the method of separating said impurities from the gas
absorbent to said absorption zone.
10. In a process in which a hydrocarbon is pyrolyzed 40 free of impurities from the bottom of said second strip
mixture which comprises: introducing the gas mixture into 45
an absorption zone wherein said impurities including sub
stantially all of said methyl acetylene and a minor amount
of acetylene are absorbed in a naphtha absorbent having
a boiling range between about 300° F. and about 500°
F., said absorption zone being maintained at a tempera 50
ture between about 60° F and about —20° F. and a pres—
sure between about 30 p.s.i.a. and about 200 p.s.i.a., pass
ing bottoms from said absorption zone to a ?rst stripping
References Cited in the file of this patent
UNITED STATES PATENTS
1,422,183
2,301,240
2,714,940
2,838,133
Curme ______________ __ July 11,
Baumann et a1 _________ __ Nov. 10,
Milligan _____________ __ Aug. 9,
Schreiner ____________ ..._ June 10,
1922
1942
1955
1958
FOREIGN PATENTS
797,120
Great Britain _________ __ June 25, 1958
UNITED STATES PATENT OFFICE
CERTIFICATE OF CORRECTION
Patent No° $023,843
March (JW 1962
George Craig Grubb et alo
It is hereby certified that error appears in the above numbered pat
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 2,
line 59,
for "as” read —— a ~—>~; column 5v
TABLE V, column Llv line 7 thereof, for "075" read
-- J4 --; column 7, line 56, for "with" read
—— without -—; column l0I line 28, after ‘"pyrolysis‘“ Insert
--
product
——.
Signed and sealed this 29th day of May 1962a
(SEAL)
Attest:
ERNEST w. SWIDER
DAVID L- LADD
Attesting Officer
Commissioner of Patents
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