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Патент USA US2409817

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0ct. 22, 1946.
Filed Jan. 25, 1943
Cmef /fe/wvfr/-l V/LA/vo
HfescHaL Y. HYDE
Patented Oct. 22, 1946
Clare Kenneth Viland, Martinez, and Herschel Y.
Hyde, Associated, Calif., assignors to Tide Wa
ter Associated Oil Company, San Francisco,
Calif., a corporation of Delaware
Application January 25, 1943, Serial No. 473,456
`8 Claims. (Cl. 260-683)
This invention relates to the manufacture of
olefìnic feed stock for alkylation and similar proc- ,
esses Where a high concentration of oleñns is
desirable and has for a principal object the man
ufacturer of C4 and C5 fractions containing un
usually high percentages of oleñnic hydrocarbons.
Another object of the invention is to provide
materials peculiarly adapted for pyrolytic con
version into desired oleñns.
A further object is to reduce the quantity of
normal pentane commonly present in stocks
charged to alkylation or similar processes thereby
increasing the plant capacity by elimination of
a large proportion of those hydrocarbons not
entering into the reaction.
Other objects will be apparent from the follow
ing description.
In the manufacture of modern aviation gasoline
the alkylation process has become one of the most
commonly used methods of obtaining gasoline
fractions of high antiknock rating. As is well
known, this process as most generally practiced
comprises the formation of branch-chain paraf
fins chiefly in the boiling range of the octanes by
the chemical combinati-on of isobutane with bu
tylenes. However, especially in cases where the
supply of‘butylenes is inadequate to meet the de
mands for aviation gasoline, the alkylation proc
ess is also used to produce good antiknock gaso
line components by reacting isobutane with amyl
The quantity of alkylate which may be pro
duced in any given area, therefore, is limited by
the available supply of isobutane, butylenes and
amylenes as well as by the capacity of the alkyla
tion plants. Present demands for aviation gaso
line have resulted in the constunption of prac
tically the entire supply of naturally occurring
isobutane and numerous renners have undertaken
the installation of isomerization processes to aug
ment the supply thereof. The chief source, if
not the entire supply, of the required butylenes
the remainder being chiefly normal butane. As
the normal butane cannot be readily` fractionated
from the butylenes without the use of extensive _Y
fractionating equipment, it is common practice
¿to charge the entire C4 cut to the alkylation proc
ess, along with the required amounts of isobutane.
As the normal butane does not enter into the al
kylation reaction, it passes through the plant un
changed and is fractionated from the products
10 of the reaction. This procedure offers difficulties,
however, when normal butane is present in large
amounts. First, the throughput capacity of the
alkylation reactor is reduced in proportion to the
amount of the inert normal butane which is pres
ent. Second, in order to separate the normal bu
tane from the products, a heavy load is placed on
the fractionating equipment of the alkylation
Third, since the alkylation process re
quires the recirculation of large amounts of iso
for the proper functioning of the process,
20.; Vbutane
the separation therefrom of the inert normal bu
tane Valways results in the loss of substantial
quantities of valuable isobutane into Ythe normal
butane due to imperfect fractionation. From the
above it is seen that it is desirable to charge to
the alkylation process a C4 cut with as 10W a
content of normal butane as possible.
Likewise, when amylenes are alkylated, the
amylenes are obtained by isolatingV a C5 cut from
30A the products of the pyrolytic cracking and/or
polymerization processes. Ordinarily this C5 cut
will contain from about 40% to 50% of amylenes,
the remainder being chiefly pentanes. As the
pentanes cannot be readily fractionated from the
amylenes without the use of extensive fraction
ating equipment, it is common practice to charge
the entire. C5 cut to the alkylation process, along
with the required amounts of isobutane. As the
normal pentane does not enter into the alkylation
reaction, it passes through the plant unchanged
and is fractionated from the products of the reac
tion. The presence of large amounts of the nor
ma1 pentane offers diñiculties similar to the pres
ence of normal butane during butylene alkyla
and amylenes is from the by-products of various
pyrolytic processes, such as cracking and poly
merization, which are primarily designed for the
The present invention provides a method for
manufacture of hydrocarbons within the gasoline
producing larger amounts of amylenes from py
boiling range. Due to modern demands for butyl
rolytic processes than are normally obtained
enes and amylenes for alkylation purposes nu
therefrom, and provides a C5 fraction containing
merous pyrolytic plants are being operated prin
50 from about 60% to 80% amylenes. In this way
cipally for their production of these olefins.
not only is the available supply of amylenes in
As commonly practiced, butylenes for the al
creased, but also a C5 cut is provided which con#kylation process are obtained by isolating a C4 cut
tainsasubstantially lower percentage of unreac
from the products of the pyrolytic cracking and/ or
tive normal pentane. Simultaneously there is
polymerization processes. Ordinarily this C4 cut
will contain from about 25% to 45% of butylenes, 55 produced a C4 cut which contains from about 40%
C3 hydrocarbons has been fôund to give good
to 60% butylenes, which provides a more efficient
C4 fraction for butylene alkylation than is nor
mally obtained from pyrolytic processes. The
overall effect, therefore, is to furnish additional
quantities of butylenes and amylenes and, coin
cidentally, tov increase the capacities of the alky
lation plants, whether alkylating amylenes or
In carrying out the process of the invention it
may be convenient to use a conventional thermal
polymerization plant. The accompanying draw
ing shows diagramniatically a typical thermal
polymerization plant with modiñcations for car
rying out lthe invention. In accordance with the
invention normal hexane in line I and C2 and Cs
hydrocarbons in line 2 are charged to pyrolytic
Briefly described, the invention comprises sub
jecting normal hexane to pyrolytic decomposition
Zone @through line 5; the proportion of each be
ing controlled by valves 3 and il. In pyrolytic
in the presence of substantial amounts 0iA Dro
pylene and ethylene. When normal hexane is
subjected to temperatures in the range, of 100,0`ov
zone Èthe mixture isheated to the reaction tem
perature in coils? and 8 and the resulting prod
to 1300° F., it is decomposed'into various ole- '
finie and parafñnic hydrocarbons as a result'. of
, ucts. leave, through line 9.
Suitable pressure is
maintained upon the mixture in the pyrolytic zone
several more or less simultaneously occurring re
actions oi which the following appear. to predomi
by meansof valve Iii. From line 9 the products
enter fractionating Zone I l (which may advanta
geously comprise several, fractionating columns
20 arranged in accordance with well known princi
ples of fractional distillation) wherein they.. are
fractionally distilled'. to recover desired.; fractions,
shown diagrammatically as leaving through lines
I2, I3; I Il, I5, IBI, and. Ia'I' in the respective order.
quantities »of propylene and ethylene are mixed ,25. of their boiling‘ranges.` Through line I£2 is with»
with the normal hexaneY prior to Carr-ying out the
drawn methane, and any hydrogen, formed; dur
decomposition, The presence of the -Cz and espe
ing the reaction and suilicient ethylene (and
cially the C3 oleñns tends to suppress. (2) and» (il).
ethane, if desired) tov maintain the concentra
In accordance with the invention substantial . n
and thereby increases the'amount of material un
dergoingV reactions 1 and> 3, resulting` in- the for
mation ofy larger amounts of- amylenes and buty
lenes. Reaction 4 may be still further retarded
by the addition of propane also Vto the mixture
prior to pyrolys'is. Likewise, if desired, ethane
may` also, be added resulting in a suppression of 35
Reaction 3 with a corresponding- decrease in theA
production of'but-ylenes andan increase in amy
tion of C2 hydrocarbons> Withdrawn through line
I3 within the desiredy range. This.y overhead -gase
ous fraction mayI be used as fuel’.
The remain.
ing C2 hydrocarbons togetherf'with the C3 hydro».
carbons are withdrawn through line I’f‘i and re.
cycled to the process throughv lines` t8. and. Ii.9„
being mixed with incoming fresh. charge of: ,C2
and C3. hydrocarbons in line f2ì or 5.' Through
line I4 is withdrawn a C4 cut which, under. the.
operating conditions. of the' invention, wilifcon
tain from about 40%4 tot 60% of butylenes.A
malA hexane is‘subjected> to pyrolysis to- produce 40’ Through line I5 is withdrawn. the desired Cs.
amylenes, the percentage of amylenes produced
cut which, underv the operating conditions ofithe
maybe increased by increasing the concentration
invention, Will. contain l'rom- about> 601% to..30.%`
ofan'y one of" the Czior C3 hydrocarbons present
of amylenes. As previously. stated, these. Grandi
lene production.
From the above :it may be seen' thatjvvhen nor-.
during ’the reaction.
However, best results are
C5 cuts may advantageously be usedlas. ole'ñnicI
obtained by increasing the concentration of alll 45 feed. for alkylation processes. 'Through line,x Iï'di
the C2 and C3 hydrocarbons, especially thelC'z and
is withdrawn a depentanized polymer gasoline;
C3V oleñns.
Under the temperature conditions ofthe reac
While. poly-mer - taßrs> leave» the fractionating Zone
through lineA Irl". If` desired;normalhexanamay`
tion, and’l especially in the temperature rangen-i
be fractionated from the» polymer ‘gasoline in la'.
1050° F. to 115,0" E.; 'there occur, 'simultaneously~ 50 second fractionati-ngY zone» (notshown)Y andoree '
withl the decomposition ofithe‘hexane‘, 'polymeriz
cycled to the process (through lines not shown)A
ing'reactions among the C2 andCa 'hydrocarbons'
to be..m-i»xed with the‘fresh normal hexanein;> line
present resulting in the formation of additional"
quantities of amylenes and’ butylenes -`together
Normal hexane: for` lconductingrthe` process off.
with a large quantity of polymer'> gasoline of good 55 the invention maybeproducedlin :most reñneri’es.:A
manufacturing aviation gasoline, being. obtainecü`
anti-knock value. ‘Isobutane, normalbu-tane, iso
pentane, normal pentane, and, in minor propor
as a Icy-product of relatively.. lowv value in.~the.~«
tions, polymer tarsl and other products are also
fractionation. ci?A straight rungasoline stocksgandf. »
formed. As stated above, the isobutane is-a‘valu- '
other stocks, for the production._'of' i'soehexane.
able constituent'for the feed stock to the alkyl-a; 60 used as aningredient in.. aviationgasoline; .'zAsLl
tion plant- Similarly,l isopentane is useful4 as a
is weilfknown, the normalhexane thus obtained;
' feed stock for alkylation.
_ is generally notof 100%. purity.. According to.
While the‘presence of' any amount ’of C2 and C3`
common practice `such a normal hexane fraction.
hydrocarbons will suppress Reactions 2 and 4;
will include hydrocarbons ¿. hav-ing 'bolli-ng., points»
above- _to some extent, the elïect increases with 65 between i45° F; and 1605’ F., suchas-f
forA exa'1n~..`
the Vamount of C2 and'Cs hydrocarbons present.
ple, â-methyl pentaneand 1,2 'dimethylxcyclobw
In orderfto, obtain'a substantial increase of Re
tane in addition to normal hexane. Depending
acti'on l the C‘z and C3 hydrocarbons should be
on the eiiiciencyv of the fractionation, a.' small
present at least in equimolar proportionv to the
amount of hydrocarbons-having higher lor flower
normalh'exane, although a greater amount is to 70 boiling points may‘alsof'be present', but generallïyl
be preferred and a ratio of C2 and C3 hydrocar
bons to normal hexane of 3 : 1`or greater is desired;`
Excellent resultshave been obtained using a molal
not in excess of 5%.~
While, foroverall reiineryemciency», it: is desire ’i
able to separatenormal hexane oi-1as-highpurity
ratio. of about 7.11. In the C2 and C3 hydrocar- _
as possible, the process of the invention is ada-pt@
bons charged as above, a ratio of 20% C2 and 80% 75 edV to operate satisfactorily on normal hexane>
stocks within the abovel range of purity. . In the
normal hexane and C2 and Cs hydrocarbons at ay
appended claims this range of purity is intended
to come Within the scope of the term “consisting
cracking temperature for suilicient time that the
essentially of normal hexane.”
desired amount oftoleñns is formed and various
apparatus may suggest themselves to a skilled-
4Following is an example of the process of the
invention conducted in a conventional thermal
polymerization plant. A freshcharge consisting
in a single coil subjectedto the necessary tem
perature, or a combination of heating» coil\and
reaction chamber `may be used if so desired.
Pressures employed in conventional polymeri
zation plants are usually in the order of 300Y to
500 lbs. per squareínch'at the outlet transfer> line.
While this pressure is preferable, for operating
of about 12 minutes. The products were then
fractionally distilled into a gas fraction, a recycle
fraction consisting Í‘of all the Cs hydrocarbons
together with a portion of the Cz hydrocarbons
formed, a C4 cutcontaining all the‘Cr hydrocar-`
bons formed, a C5 cut containing all the C5 hy»
drocarbons formed, a depentanized polymer gaso
line fraction, and a residual tar fraction. It was
found that the C4 fraction contained 50% of ole
flns andthe C5 fraction contained 65% of olefins.
The followingtable shows results obtained com
reasons, in the practice of‘ the invention, other
pressures may be used from atmospheric; or be'
low. to one hundred or more atmospheres.` “
ried out in a series of fractionating columns under
pressures suiiicient` to properly condense the'nec
essary products and refluxes at the temperatures
employed. The conditions of operation and de
sign of such fractionating towers is well known
to distillation engineers.
po ymeriza
materials undergoing the reactions will be above
the critical temperature, and consequently, in the
Propylene ....................... __
_ ._
N. hexane stock (l45°-l60° F. ___.
1, 000
____________ __
Total _________________________ ._
l, 800
l, 000
4, 000
1, 000
4, 000
5, 000
5, O00
vapor phase.
C2 hydrocarbons ________________ __
O3 hydrocarbons ................ __
N-pcntanc. _ _
Other products ____________ __
'I‘otafLÓ ____ __lt_ _________ __; _____ _.
4 frac ion per cen.:
_ _
12. o
50. 0
N-butanc_ _
38. 0
TotaLC. _______________ _ _1.; _____ _ _
100. 0
5 fraction per cen z
Amylenes _______ _.
N~pentane ______ __
17. 4
65. 2
17. 4
hexane to a temperature in the range of 1000° F.
to 1300° F. while in the presence of added amounts
of hydrocarbons from the group consisting of
ethane, ethylene, propane, and propylene and in
Isopentane ____ _.
l, 320
We claim:
1. The process of producing a mixture of C5
hydrocarbons containing a high proportion of
amylenes which comprises: subjecting a hydro
carbon fraction consisting essentially of normal
Recycle stock, bbl/day:
Analysis of
merization plant (including both the feed and re
cycle stocks) is generally in the liquid phase.
ously, at the cracking temperatures involved, the
Fresh charge, bbL/day:
charge of normal hexane and C2 and C3 hydro-`
carbons according to the invention may be either
in the liquid or vapor phase as desired. Obvi
aäìlä‘àeâîg allthernial
This is, however, merely an expedient and the>
to mventlon
Analysis o
Likewise, the'charge to the conventional- poly-ï
Propane ................... __
Fractionation is, in practically all cases,"car'-
degree of heat than those of the second section..
The process of the invention‘maybe carried out
temperature was reduced to 1050° F. over a period
erally divided into two sections; the tubes'i or coils
cf the `iirst section- beingsubjected to a higher
of 600 barrels per day of propylene, 200 barrels
per day ‘of propane, and 1,000 barrels per day` of
normal hexane stock, together with 4,000 barrels
per day of recycled C3 hydrocarbons and 1,000
barrels per dayl of recycled C2 hydrocarbons, was
charged to the heating coil of the polymerizae
tion plant wherein the temperature was raised to
1125° F. The products from the heating coil
were passed to the reaction section wherein the
pared to conventional operations where Ca hydro
carbons are polymerized under similar operating
`Conventional polymerization furnaces are gen
the substantial absence of other added hydrocar
bons; fractionally distilling the resulting prod
ucts; and separating therefrom a mixture of C5
hydrocarbons; the molal ratio of normal hexane
21. 7
to Cz and C3 hydrocarbons subjected to the reac
23. 5
a4. 8
tion being between about 1:1 and about 1:7.
2. The process according to claim 1 wherein the
100.0 55
molal ratio of normal hexane to C2 and C3 hy
2G. 0
50. 0
drocarbons subjected to the reaction is not greater
30. 0
than 1:3.
3. The process according to claim l wherein
60 the molal ratio of normal hexane to Cz and C3
hydrocarbons subjected to the reaction is about
From the above table it is seen that, by intro
ducing normal hexane into the charging Istock
4. The process of producing a mixture of C5
of the polymerization plant in accordance with
hydrocarbons containing a high proportion of
the invention, the yield of C4 and C5 hydrocar
amylenes, which comprises: subjecting a hydro
bons is greatly increased together with a substan 65 carbon fraction consisting essentially of normal
tial overall gain in the percentage of oleñns
hexane to a temperature in the range of about
1050° F. to about 1150° F. while in the presence
Although a conventional thermal alkylation
added amounts of hydrocarbons from the group
plant using normal operating conditions of time,
temperature, and pressure is well adapted to the 70 consisting of ethane, ethylene, propane. and pro
pylene and in the substantial absence of other
carrying out of the invention and although such
added hydrocarbons; fractionally distillingV the
operation is a preferred form of the invention,
resulting products; and separating therefrom a
the invention in a broader sense is not limited to
mixture of C5 hydrocarbons; the molal ratio of
such operation. Any equipment may be used
which is capable of maintaining the mixture of 75 normal hexane to Cz and C3 hydrocarbons sub
Total _________________________ __
100. 0
100. 0
jectedl to.v the; reaction being between: aboutl 1':1
and about 1:7:
5. 'Iîhe'process of= producing a mixture of C5.
hydrocarbons containing a high proportion of
normal hexanefìs.y cracked. forming. amylenesp, iid@
ducingthe. temperature'of the. resulting products,
fracti‘onally1 distilling the resulting products> and
separating therefrom a, fraction composed'ma-in-ly
amylenes and a mixture of C4 hydrocarbons con
of the» C5; hydrocarbons present in said products;
taining a highr proportion of butylenes, Which
the molal rati'o of' normal hexane to C2V and C3
comprises-1 subjìecting a `l'iydrocarbon :Eractionì`
hydrocarbons subjected. to the. reaction being;v be
consisting essentially-of normal hexane to a„tem--,` tweenabout 11: 1: and about. 1:7.V
perature in the. range` of 1000o F'. to 1300" F. while;
7. A method comprising thermally cracking at..
in the presence-„of added amounts of hydrocar 1.0 a. temperature in the-order’of v1000" F. to 1300o l?.
bons from` they group consisting of ethylene; pro
a. mixture of. normal hexane, Cahydrocarbonsand
pane, and propylene and inthe substantial ab-r
Cs; hydrocarbons while in the. substantial absence
sence of other. added hydrocarbons; fraotionally
of other added hydrocarbons and fractiona'lly dis-_
distilling. the resulting products; and separating
tilling a. Ceiraction from'the resulting: products;
therefrom a mixture of C5 hydrocarbons and a 15 the rnolal` ratio: of normal hexane to C2 and» C3;V
mixture. ofV C4 hydrocarbons; the molal ratio of
normal hexane to C2 and C3 hydrocarbons sub
jected to the reactionV being between about 1:1
and about 1:7.
6. The process of producing, a mixture of C5l 20
lîxydrocarbons` containing a high proportion of
amylenes which comprises: flowing.. ay stream of
hydrocarbons. consisting essentially of normal.
hexane through a conduit', simultaneously ñow
ing a stream consistingv of hydrocarbons lighter 25
than C4 hydrocarbons. and heavier than methane
through said conduit in adrnixture. with-said nor
mal hexane while in the substantial absence of
other added hydrocarbons,_heating the mixture in
conduit to. a temperature. between 1000" F; and 30
1300" F., maintaining, the mixture at said' tem
perature. for. suñîcient time thatl a. portion ofthe
hydrocarbons subjected tothe reaction being be
tween about. 1: 1- and about 1 :
8. A processY of' producingl C51 hydrocarbonsl
which comprises: heating' normal hexane- to aA
crackingtempera'ture in the order of. 10009 F.`> to
while inthe presence of an added quan
tity> of Czfand Cs hydrocarbons >and in the sub.-v
stantial absence ofl other added hydrocarbons, and
maintaining such temperatureV for a period of
time sufficient to form a C5 fractionr containing
in: the order of from 6,0%, to 80% of olei'his;` the
molaliratio of* normal hexane-toCz and Cshydro
carbons. subjected- to the reaction beingV between
about 11:1 and. about 1:7.
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