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Oct. 29, 1946.
2,410,048
D. L, CAMPBELL
CHEMICAL PROCESS
Filed June 13, 1942
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2,410,048
Patented Oct. 29, A1946
UNITED ASTATES PATENT OFFICE
2,410,048
CHEMICAL PROCESS
Donald L. Campbell, Short Hills, N. J., assigner ‘to
Standard IOil Development Company, a ‘cor
poration of Delaware
Application June 13, 1942, Serial N0. ‘446,871
‘8 Claims. (Cl. 260-680)
i
drawn from the bottom of the absorber is re
This invention pertains to the `production of
`oleiins and dioleñns.
Most processes for dehydrogenation, whether
leased to a point previous to the ñrst stage of
compression or cooling where it is contacted with
by thermal cracking, `iixed -bed catalytic crack
ing, `or Huid catalyst cracking operate to discharge
ing at very low pressure and at as high an oper
products lfrom the `reactorata low total pressure,
ating temperature «as possible flashes the dis
solved compounds from the fat oil and makes the
the hot gaseous reactionproducts. This contact
'say .from Va pressure of `50 4mm. absolute to a
pressure of l0 lbs. gauge. -Whether the feed stock
resultant Ylean oil ysuitable Yfor re-use in the ab
sorber.
is butane to be dehydrogenated to butene, bu
Heat for the stripping of the absorbed con
tene to be dehydrogenated to butadiene, or butane 10
stituents from the fat oil -is furnished -by the
to be dehydrogenated to butadiene, the products
sensible heat in the reaction products. A fur
include a large amount -of gases lower boiling
ther beneiit is obtained in that since vit is neces-
than C4. yThis means that it is impracticable to
recover all the C4, including the desired butene
or butadiene product in the liquid state by simply
sary .to «quench the gaseous reaction products,
contacting the >hot gaseous reaction products
with fat oil serves the dual purpose of quenching
cooling the products or by a simple combination
the reaction products and stripping the fat oil.
of compression and cooling even with injection
rIïhe vapors stripped from the pfat oil recycle
of liquid from the lower pressure condensing
through the compressors to the final stage where,
‘stages tothe higher pressure condensing stages.
Thus it is desirable to add an absorption system 20 due to the fact `that they are richer in higher
boiling constituents than is >the non-condensed
to ‘compression in order to recover 'the full pro
gas ordinarily remaining after the last Vstage of
duction of C4 cut.
.
compression and condensation, some of these ,re
It is an object of 'the present invention ‘to pro
cycled, absorbed, and .stripped vapors condense.
>formed in ‘any high 'temperature dehydro‘genation, 25 The undesired llower .boiling constituents do not
condense 'but go on to the absorber where vthey
dehydrohalogenation 4or thermal cracking proc
constitute a recycle `gas »and eventually they leave
ess and recovering a maximum of oleñns and
the top of the absorber with the dry gas. .The
dioleñns therefrom by a combined compression
increase in gas to be compressed and to be 'han
and/ or cooling and »absorption system.
i
It is also an object of this invention to provide 30 dled in the absorber is not substantial. -
vide a novel method of quenching reaction gases
a novel method of stripping Wet "gas 'absorber oil
in order that it may be reconditioned `for use in
the absorption system and any C4 or C5 com
pounds contained‘therein directly ‘returned to the
My process is intended ,primarily to l»be used in
connection with the production of butadiene from
ñxed bed catalytic cracking of normal butenes.
However, it could ralso be'used in connection with
35 iixed bed catalytic cracking of butane or a mix
process.
It is a `i’urther object of this invention to pro- `
vide the lart with a novel .process of dehydrogenat
ing AC4 and C5 >compounds to oleñns and dioleñns
and recycling unconverted compounds to the
initial dehydrogenation step.
ture of C4 stocks to make butadiene or of butane
to make butene, or of iiuid catalyst cracking with
any of the above processes, or with thermal crack
ing ‘with .any of `the above processes, or of ther
40 mal'cracking with 'steam with any of the above
processes, or with high-temperature, low-pres
sure thermal cracking with or without steam,
or of heavy naphtha or gas `oilto make butene,
.According to my invention, the hot reaction
butadiene, or both.
gases from a high temperature dehydrogenation
The ‘ñ'gure of the accompanying drawing illus
or cracking process are quenched by direct con 45
trates diagrammatically a ’ñow'plan of my proc
tact with a fat oil whereupon the reaction gases
ess as applied to the production of `butadiene by
are subjected to a compression and/cr cooling
Other objects will appear from the detailed
description andthe claims which follow.
.
treatment in order to condense as much of the
heavier constituents as lis possible. The uncon
densed portion is then passed through an ab
sorber wherein it is contacted with a suitable
absorber oil which serves to withdraw the re
the dehydrogenation of butene.
`
As shown in the drawing, I represents `a `source
50 of supply of materials suitable for conversion to
'dioleñns, while 2 represents any suitable means
for for-ming dioleiins at high temperatures, as
-by catalytic dehydrogenation, thermal cracking,
mainder of the desired C4 and higher compounds.
dehydrohalo'gen'a'tion vand the like. »Each Yof these
'_I‘hegas passing out of the top of the absorber
is released to the >burner line. lThe fat oil witn 55 processes is characterized by the formation of
2,410,048
3
dioleñns at such high temperatures that the di
oleñn is thermally unstable. These processes are
Well known to th-e art and need not be described
here in detail. Suffice to say, butadiene may be
produced by dehydrogenation of n-butane or the
n-butenes with or without a catalyst, or by de
hydrochlorination of n-butene ,dichloride Iso
prene and other> C5> dioleñnes may similarly be
prepared from pentane and the pentenes or from
4
through a cooler and condenser 53 to a separator
I I wherein some of the water present is removed.
The gases are then passed to compressors I2'
wherein they are compressed to from about 1/2
to about 370 pounds per square inch gage. The
compressed reaction products are then passed
through Acooler and condenser 29„wherein they '
are cooled to about 65° lïkto'liquefyv the C4 hy
drocarbons and then passed to a separator I3
the pentene dichlorides.
1 o. »wherein most of the remaining water is removed
For illustrative purposes, the drawing shows- as the bottoms and the liquefied C4 fraction is
an effective arrangement for catalytically'dehy
vremoved through line I4 and passed to the sta
drogenating butene to butadiene. _In this ar- ` bilizer I5. The overhead from separator I3 is
rangement 3 represents a heater for preheating
passed to the wet gas absorber I 6 wherein it is
the butene to about 1200° F. or just below reac
brought into contact with a suitable absorber
tion temperature. 4 is a heater which serves to
oil such as light gas oil in order to recover es
superheat the steam obtained from the live steam
sentially all ofthe uncondensed C4 hydrocar
supply line 5 to a temperature suiiicient, upon
bons, particularly butadiene. Hydrogen, carbon
admixing of the steam with the butene in suitableV
dioxide, propanes and lighter hydrocarbon gases
proportions, to raise .the temperature thereof to 20 in dry form are discharged through outlet, I'I..
reaction temperature. The steam may, for ex
The absorber oil used in absorber I6 becomes
ample, be under a pressure of 40 lbs/sq. in., at a
more or less saturated with _the Cs and’higher
temperature of 14:00c F. and admixed with butene
hydrocarbons contained in the gases passed
in the ratio of 7 volumes per volume of butene.
therethrough and it becomes necessary periodi
Reactors 6 and 'I are provided, which contain 25 cally to subject the saturated or fat oil to a strip,
a suitable catalyst. It is preferred that the cata
ping operation. VInstead of providing a separate.
lyst by one >having both dehydrogenation and
Water gas activity. A suitable catalyst of this
type is one containing magnesium, iron, potas
sium and copper oxides. Since a small amount
of side reaction occurs unavoidably, there is some
coke formation in the reactors. While most of
the coke formed is converted almost immediately
during the run of the reactor, due to the Water
gas activity of the catalyst, it is preferable to
shut olf the supply of butene to the reactor pe
riodically while continuing the supply of steam,
whereby any residue of coke in the reactor is
converted to CO2 and H2. Accordingly, the re
actors are generally arranged in pairs, so that 40
, one can function to dehydrogenate butene While
the otherçis subjected to a steaming operation
to convert any coke present therein and revivify
the catalyst. While the on-stream and steam--y
ing periods may be varied somewhat, it has been '
>stripper therefor, the fat oil may be stripped in
an advantageous manner by passing it through
line I8 to quench tower 9 where it serves as'Y the
quenching ñuid. The fat oil may be, supplied to
the quench tower atabout 85° F., the tempera
ture at which it, isidischarged vfrom the absorber,
or if desired it may be subjected to suitable heat
control before injection to assure proper _quench-V
ing in tower 9. If the temperature >ofthe lfat
oil is such that the quench tower Scannot take
the full cooling effect of the fat oil, it may bé
passed in heat exchange relationwith the lean
oil to effect temperaturey adjustment. v-The hot
reaction gases strip the fat" oil, thereby directly
returning the absorbed C4 hydrocarbons tofthe
reaction products discharged from the tower-` 9.
The stripped or lean oil may be removed ,from
the tower 9 and returned through line I9- tothe
wet gas absorber I6 preferably after `passing
through cooler 26 wherein the lean oilis vcooled
found convenient when the reactors are arranged
in pairs, to have the cycle consist of 1-hour de
to about 60° F. or suñ‘lciently low to assure effi
' hydrogenation time followed by l-hour steaming.
cient absorption of the C4 fraction inthe yab
The butene-steam mixture is passed through
the catalyst space at the rate of 500 volumes of 50 sorber I6. Auxiliary Ystripping means, not shown,
butene (measured at standard conditions) per
The bulk of the oil in quench tower 9 is continue
volume of catalyst per hour. The temperature
ously recirculated by means ofa pump I0. Due to
at the inlet to the catalyst zone is approximately
a gradual accumulation of polymers inthe recir~
1300° F. and the reaction mixture is discharged
culated oil, it is necessary to bleed olf some of this
from the reactor at about 11'75" F. The buta
oil to effect a separationof these polymers. Fresh
diene is quite unstable at this temperature and,
make-up oil or the oil after the polymer separa
to prevent or minimize degradation thereof as by
tion -is lsupplied to the system -either through
polymerization, it is essential to cool or quench
connection 5I at the quenching tower` or Vth'roug
the reaction mixture as rapidly as possible. Ac
cordingly, the products leaving- the dehydrogena-Y 60 connection 54 at the wet gas absorber I6. `
' '
The C4 fraction removed from separator I3
tion zone are quenched with a suitable cooling
fluid supplied through line 52 which fluid may be
passes to the stabilizer I5wherein it is subjected
water or fat oil hereinafter mentioned from ab
to 'a fractional distillation to remove any gaseous
sorber I6, and then passed through waste heat
impurities contained therein which pass as over
mayalsobeused.
boiler 40 to the quench tower 9 wherein the reac- '
tion gases are cooled to from about 550° F to
about 300°?. i. e., a temperature sufñciently low
that the dioleñn is thermally stable but not low
enough to condense the steam. A pump I0 is pro
vided in line 3| for recirculating the quenching
fluid through'the tower 9. A cooling coil or other
heat removal facilities 8 may be provided in the
`
-
'
a
.
head to separator 20 and are discharged at- 2I`.V
A liquid reflux may be returned from separator
2B tor the'still ‘I5 through line 21. Theïbottoms
from still I5 are passed toa rerun tower 22`wheref
in they are again subjected to fractional distilla
tion. llf'he C4 cut passes as overhead'to separator
23, wherefrom a >negligibleamount of Vgases are
removed as overhead and the C4 fraction, _con
line 3I to give the necessary temperature control
taining essentially'butadiene, unconverted bu
in the quenching operation. The quenched
tene and some butane, is removed at 24Jand
gaseous reaction products are then passed 75 passed to a suitable extraction means 25 wherein
2,410,048
6
4butadiene is :separatedfrom the butene and .bu
tane. The butene and butane separated in ex
tractor 25 may be returned through line 30 to
to a temperature suiñciently low to inhibit Ide
supply I for recirculation in‘the process.
In certain process of preparing diolefins, as in
using dehydrogenation catalysts which `:are
harmed by steam and require its exclusion from
tion step first with water and then with arela- 1
tively cool liquid comprising `a fat oil, separating
cooled product gas from the quenching liquid,
the feed, the reaction product may not contain
gas, separating uncondensed gases from said
liqueñed .C4 fraction, washing said uncondensed
gradation of the dioleñns presentby contacting
the hot reaction products from vsaid dehydrogena
liquef-ying a C4 fraction in said cooled product
any water, in which event water separation .in II
and I3 would not be necessary unless, >of course, .10 gases lwith an absorber oil .to recover diolefins
therefrom, utilizing the fat `oil formed in this
water is used in the initial quench. When the re
i washing step in the aforesaid quenching' step '
action product is free from wateigitmay, if de
thereby stripping said fat oil of absorbed -buta
sired, be Ycooled sufficiently to liquefy the C4 and
diene and butene, cooling .the stripped oil and
higher hydrocarbons without any danger of ice
. ‘
formation thereby obviatingthe necessity of com 15 returning it to said :washing step.
>4. The process `of producing butadiene which
pressing the reaction gases. In this case, the
comprises dehydrogenating butene to butadiene
reaction gases would be ‘by-passed around theV
at elevated temperatures, rapidly >quenching the
separator II and compressor I2 and would go di- `
reaction product from said dehydro-genating >step
r-ectly from the quench tower 9 through line 28 to
the cooler or condenser '29 and thence to a sepa
20 to a temperature sufficiently low to inhibit «degra
dation `of the dioleñns present by contacting the
hot reaction products from said .dehydrogenation
step first with water and then with a relatively
cool liquid comprising a fat oil, separating cooled
absorber IIS.
`
While the above description is for the most part 25 product gas from the quenching liquid,«liquefying a C4 fraction in said cooled product gas, sep
directed to the production of butadiene, it is to be
arating uncondensed gases from said liquefied C4
understood that my invention is not limited
fraction, subjecting the liquefied C4 fraction to
thereto but is applicable to the production of
fractional distillation to separate gaseous impur
oleñns and dioleiins in general since, at most,
only minor alterations in4 temperatures, pressure, 30 ities as well as C5 and higher molecular com
pounds from a fraction consisting essentially of
and the like, from those disclosed above would
butene and butadiene, washing said uncondensed
be made when applying my process t0 the produc
gases with an absorber oil to recover dioleñns
tion of other compounds.
therefrom, utilizing the fat oil f_ormed in this
What I claim and desire to secure by Letters
35 washing step in the aforesaid quenching step
Patent is:
thereby stripping said fat oil of absorbed buta
1. In the process of producing butadiene and
diene and butene, cooling thestripped oil and
homologues thereof wherein the diolefin is formed
¿returning
it to said washing step.
at relatively high temperatures, the improvement
5. The process of producing butadiene which
which comprises rapidly quenching the reaction 40 comprises
dehydrogenating butene to butadiene
products from the high temperature dioleñn for
at elevated temperatures, rapidly quenching the
mation step by contacting the hot reaction prod
reaction product from said dehydrogenating step
rator I3 wherein the liquefied product would be
separated from the Wet >gases and passed to the
stabilizer I5 while the wet gases are passed to the
ucts ñrst with Water and then with a relatively
to a temperature suiiîciently low to inhibit deg-`
cool liquid comprising a fat oil, separating cooled
product gas from the quenching liquid, liquefying
radation of the dioleñns present by contacting
the hot reaction products from said dehydrogen
ation step first with water and then with a rela~
tively cool liquid comprising a, fat oil, separating
cooled product gas from the quenching liquid,
liquefying a C4 fraction in said cooled product
a dioleñn-containing fraction in the cooled prod
uct gas, separating uncondensed gases from this
fraction, Washing said uncondensed gases with an
absorber oil to recover dioleñns therefrom and
utilizing the fat oil formed in this Washing step 50 gas, separating uncondensed gases from said `
liquefied C4 fraction, subjecting the liquefiedyC4
in the aforesaid quenching step.
2. In the process of producing butadiene and
fraction to fractional distillation to separate gas
eous impurities as well as C5 and higher molecu
lar compounds from a fraction consisting essen
homologues thereof wherein the dioleiin is
formed at relatively high temperatures, the im
i provement which comprises rapidly quenching
55 tially of butene and butadiene, separating the
butadiene from the butene in said product, recy
the reaction products from the high temperature
dioleiin formation step to a temperature suñi
ciently low to inhibit degradation of the dioleñns
present by contacting the hot reaction products 60
first with water and then with a relatively cool
liquid comprising a fat oil, separating cooled
product gas from the quenching liquid, liquefying
a dioleñn-containing fraction in the cooled prod-V
uct gas, separating uncondensed gases from this
fraction, washing said uncondensed gases with an
absorber oil to receover diolefins therefrom, uti
lizing the fat oil formed in this washing step in
cling the butene to the dehydrogenation step,
'washing said uncondensed gases with an absorb
er oil to recover dioleñns therefrom, utilizing the
fat oil formed in this washing step in the afore
said quenching step thereby stripping said fat oil
of absorbed butadiene and butene, cooling the
stripped oil and returning it to said Washing step.
6. The process of producing butadiene which
comprises dehydrogenating`butene to butadiene
at elevated temperatures, rapidly quenching the
reaction product from said dehydrogenating step
to a temperature sufliciently low to inhibit deg->
radation of the dioleñns present by contacting
said fat oil of absorbed diolefins and returning 70 the hot reaction products from said dehydrogen
the stripped oil to said washing step.
ation step first with water and then with a rel
3. The-process of producing butadiene which
atively cool liquid comprising a fat oil, separating
comprises dehydrogenating butene to butadiene ' cooled product gas from the quenching liquid,
liquefying a C4 fraction in said cooled product
at elevated temperatures, rapidly quenching the
gas, separating uncondensed gases from said
reaction product from said dehydrogenating step
the aforesaid quenching step thereby stripping
J¿2,410,048
liquefied C4 fraction, washing said -uncondensed
Lgases'with an absorber oil to recover diolefms
-therefrom, utilizing the iat oil formed in this
vWashing .step in the aforesaid quenching step.
Y:thereby stripping said fat oil vof absorbed buta
diene and butene, cooling the stripped oil, re
turning it to said washing step, withdrawing a
part of the absorber oil from the system, separat
ingvthe polymers contained therein and return
>ing the purified absorber oil to the system.
8
in this Washing step as the fat oil for contact with
said partially: `quenched product gases thereby
stripping said fat oiloflabsorbed buteneand
butadienacooling the stripped absorber oiliand
returning it to said Washing step.
`
,;
L
.8. In the process for the production of diele
Iinic hydrocarbons by a high temperature reac
.rtion,_theimprovement Which comprises contact
in-gfthehot gaseous reaction products ñrst with
Water and then with a relatively cool liquid com
„ 7. The process of producing butadiene ,which
prising a fat oil, separating the cooledgaseous
>comprises vdehydrogenating butene to butadiene
reaction products from said oil, liquefying a frac
at elevated temperatures, partially quenching the
tion containing the bulk of the 'dioleñniccom
freaction‘ products from the dehydrogenation step
pounds in said ,reactiomproducta vseparating un
by contacting the same with Water, contacting 15 condensed gases from said liqueiie'd> fraction,
the partially quenched reaction products with
Washing the uncondensed gases with an absorb
Arelatively cool fat oil thereby stripping'the fat
er oil to recover dioleñnic compounds therefrom,
oil and cooling the product gases, separating
,using the fat oil obtained in the Washing step as
cooled product gases from the stripped oil, liq
the fatoil for contacting said hot gaseous reac
uefying a C4» fraction in said cooled product 20 tion products, vthereby stripping said fat oil Vof
gases, separating uncondensed gases from 'said
>absorbed diolefmic compounds andreturning the
yliqueñed C4 fraction, Washing said uncondensed
stripped oil toj the Washing step. _
> i Y
gaseswith an absorber oil to recover butadiene
‘and butene therefrom, using the fat oil obtained
DONALD L. CAMPBELLL
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