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Патент USA US2404050

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July 16, 1946.
Filed Feb. 22, 1943
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Patented July 16," 1946
George R. Gilbert, Elizabeth, N. J., assignor to
Standard Oil Development Company, a corpo
ration of Delaware
Application February 22, 1943, Serial No. 476,709
1 Claim. (Cl. 19E-52)
The present invention relates to a process for
conversion of lower molecular weight hydrocar
bons to higher molecular weight hydrocarbons.
More particularly, the present invention is con
cerned with a process for the simultaneous pro- n
duction of a relatively high octane number motor
fuel, a high octane number aviation-gasoline
and an olelinic gas.
In the alkylation of normally gaseous oleñns
with isoparaiiins such as isobutane and isopen- _
tane using sulfuric acid as the catalyst there i's
produced a saturated mixture of liquid hydro
carbons boiling in the range between about 120°
F. and 500° F. The material boiling between the
ranges of 120° F. and about 275° F. is usually re
invention, the material of high octane number
produced by thermal or catalytic reforming of
the heaviest alkylate fraction is largely saturated
in nature and thus finds ready acceptance as
a motor fuel. While this fraction is suitable
for use as a motor fuel by virtue of its high con
centration of isoparaiiînic hydrocarbons, it also
may be adapted for use in aviation gasoline pro
vided the small amount of olefins contained
therein are removed so that the desirable iso
parañîns may be recovered.
The olefinic fractions resulting from the pres
ent operation find ready acceptance for produc
tion of still larger amounts of the constituents
of aviation fuel by recycling them to the alkyla
moved frorn the product by fractional distilla
tion Zone or they may be used as raw materials
tion and is used as such in aviation fuels because
of its saturated nature and high octane num
for the production of the dioleñns which ñnd
The fraction boiling between 275° F. and
ready use in the manufacture of synthetic rubber.
In fact, the invention specifically contemplates
about 320° F. or higher is used as an aviation 20 that the heaviest alkylate fractions may be ther
blend stock while the fractions boiling above
mally or catalytically reformed in the presence
of steam for high conversions of the alkylate
automotive equipment. The present invention
fractions to isobutylene, which is an important
is concerned with a conversion of these higher
ingredient in the manufacture of butyl rubber.
boiling fractions produced by alkylation of iso 25 In the foregoing discussion the term “thermal
paraflins with oleiins into motor fuels of suit
' or catalytic reforming” has been used frequent
able boiling range for use in internal combus
ly. By thermal or catalytic reforming is meant
tion engines and of an appreciably higher octane
conversion of the hydrocarbon molecules of the
number than that of the heavier fractions re
heaviest alkylate fraction into components of a
moved from the alkylation product. An impor
less saturated nature having a lower molecular
tant feature of the present invention is the pro
weight and lower boiling points than that of the
duction of large quantities of gases rich in ole
material charged to the thermal or catalytic re
fmic constituents which find wide use in syn
forming Zone, It is understood that this term
employed hereinbefore and hereinafter may also
In its broadest aspects, the present invention
include rearrangement as well as cleavage reac
contemplates a process for the production of
tions of the hydrocarbon molecules. The degree
three valuable constituents from oleñns and iso
of conversion is so regulated in the practice of
paraflins, by reacting an isoparaflin with an ole
the present invention by adjustment of the tem
lin by the well known sulfuric acid alkylation
perature and pressure in the conversion that it
process, separating the resulting alkylation prod
does not substantially exceed 30% by weight of
uct so that isobutane is recovered for recycling
the charge.
to the process, normal butano is discarded and
The invention will be more fully described by
aviation gasoline is segregated for use as such,
reference to the accompanying drawing in which
and submitting the heavier fractions to thermal
the single figure is a flow diagram illustrating a
or catalytic reforming. The products from the 45 general method of ñow for the process of the
thermal or catalytic reforming are then sub
present invention.
mitted to a fractionation whereby constituents
Referring now to the drawing, an olel'lnic hy
comprising propane or lighter hydrocarbons are
drocarbon feed, which for purposes of illustration
separated and oleñnic fractions comprising the
will be assumed to comprise the C4 mono-olefins,
C4 hydrocarbons are obtained. A heavier frac 50 is introduced into the system by means of line I
tion boiling in the gasoline range having an ap
and is charged into alkylation zone 2 along with
preciably higher octane number than that of
a stream of an isoparañin, such as isobutane,
the heaviest fraction in the original alkylate is
which admixes with' the oleñn feed in line I by
removed and recovered.
way of line 3. Alkylation Zone 2 is understood to
320° F. are usually blended into fuels for use in
YBy operating in accordance, with the present 55 comprise a sulfuric acid alkylation system or any
other catalytic alkylation system whereby isopar
mium oxide-alumina combinations and the like
afhn and oleiins are caused to react. Since
alkylation is a well established reaction the de
tails of its operation will not be gone into at this
The product resulting from the reaction of ole
fins and isoparaflin in alkylation reaction zone 2
are discharged therefrom by way of line 4 into
may be used.
Mention has been made hereinbefore of re
by provision is made for discarding propane and
lighter hydrocarbons therefrom through line 6,
segregation of unreacted isoparafiins by way of
high conversions 0f heavy alkylate fractions to
isobutylene with yields of about 30 lbs. of iso
forming the heaviest alkylate fraction by ther
mal treament in the presence of steam to produce
isobutylene. When operating in this particular
manner employing steam, a pressure up to about
150 lb./sq. in. gauge and a temperature of about
1000° F. with' about 60 mol per cent of steam
fractionation Zone 5. Fractionation zone 5 may
comprise one or more fractionation towers Where l0 based on the charge included with the feed, gave
butylene per bbl. of charge at about 30 per cent
feed conversion with a short contact time 0f the
line l, removal of normal butanefrom .the sys
tem through line 8 and recovery of a fraction f order of about 15 to 30 seconds.
It is to be emphasized in the practice of the
suitable for aviation gasoline from fractionation
present invention that the conditions of thermal
Zone 5 by Way of line 9. After removal of these
or catalytic reforming should not be too severe
several fractions from the alkylate there remains.
since severe conditions might cause serious cok
a fraction boiling between about 320° F. and 500D
ing but should be severe enough to allow obtain
F. which is unsuitable for use other than in motor
ing of the desired results. This particular fea
ture is obtained by careful control of tempera
The latter fraction is withdrawn from fraction
tures and pressures and time of contact.
ation Zone 5 by way of line l@ and is introduced
In thermal reforming operations, the time of
thereby into thermal or catalytic reforming Zone
contact of the hydrocarbon at the high tempera
H in which by application of suitable tempera
tures specified should not exceed 60 seconds.
tures and pressures or by the effect of catalysis
Preferably the contact times should range be
the heavy alkylate material is converted into
tween one and forty seconds.
constituents of lower molecular weight and boil
The invention will be further described by ref
ing points. This latter fraction is discharged
erence to the following examples in which typical
from thermal or catalytic reforming zone l l
operations of reforming in accordance with the
through reducing valve I2 located in line i3 which
present invention are illustrated. In each 0f the
connects to fractionation zone i4. The reformed
examples given below the charge stock to the re
material introduced into fractionation zone I4 by
forming operation was derived from an alkyla
way of line I3 is subjected to suitable conditions
tion process in which isobutane was alkylated
of temperature and pressure whereby propane
with butylenes in one system and isobutane was
and lighter fractions are distilled therefrom and
allçylated with pentylenes in another system.
removed from the system by way of line i5 and a
Both systems employed sulfuric acid as a catalyst
C4 fraction comprising the olefinic constituents is
with the two alkylates being debutanized and de
discharged from the fractionation Zone Iii by way
of line l5 which connects into line 3 whereby they 40 pentanized separately and the combined heavier
fractions from the debutanization and depenta,
admix with isobutane recycled from fractionation
nization fractionally distilled in another frac
Zone 5 by Way of line l and 3 for mixing With the
tionation stage to >discard a fraction Vboiling be
o-leñn feed in line i. Make-up isobutane to pro
10W 280° F. and to obtain a heavier boiling ma
vide a high ratio of isoparaiiins to olefins is intro
terial. This latter heavy material was employed
duced into line »3 by way of line i9.
as a charge stock in the several reforming runs
The olenns discharged from fractionation zone
described below. This material was characterized
iii by line l5 may either be recycled to the alkyl
by having an A. P. I. gravity of 55.5° F., a boiling
aticn Zone as described or may be discharged
range of 303° F. to 500° F., an ASTM octane
from the system through branch line ll; there
after they may be subjected to further treatment ¿5‘0 number of 80.4, and a C. F. R. octane number of
for production of dioleñns for use in the manu
facture of synthetic rubbers.
Example 1
.a fraction having an appreciably higher octane
above described charge stock
number than that of the material discharged
was passed through a thermal reforming unit op
from fractionation zone 5 through line lil is re
erating at a maximum tube metal temperature of
covered from fractionation Zone i4 by way of
950° F., a gauge pressure of 150 lbs/sq. in. and
line i3 and may be used as such asa motor gaso
under ñow conditions such that 15.3 per cent by
line 0r it may be submitted to further treatment
weight of the charge stock was converted into
for separation therefrom of isoparaninic constit
hydrocarbons of different bo-iling range. The
uents which find usage in aviation fuels.
In thermal or catalytic reforming Zone Il, the 60 product from this reforming operation was de
butanized and a 400° F. end point material frac
conditions of temperature and pressure will vary
tionated out of the total product. This latter
widely depending on whether merely thermal or
material had an A. P. I. gravity of 57.4, a boiling
catalytic treatment is employed. When operat
range of 82° F. to 382° F. and a C, F, R. octane
ing with thermal treatment solely a temperature '
number of 85.8. In addition to this material of
between about 900° F. and 1100° F. Yand a pres
improved-octane number, gases containing 1.2 per
sure of iGO to 600 lbs/sq. in. gauge will give good
cent by Weight of ethylene, 6.3 per cent by weight
results. When operating with catalytic treat
of propylene, 24.2 per cent by weight of butyienes
ment somewhat milder conditions will obtain.
and 25.5 per cent of pentylenes were obtained,
Temperatures in the range from about 750° F. to 70 Each of the latter three constituents have been
about 900° F. and pressures up to 150 lbs/sq. in.
found suitable in alkylatio-n reactions.
gauge have been found suitable. Silica-alumina
Example 2
catalysts and the like have been found suitable
fox` these types of vreforming operations. Also
A portion of the same charge material em
activated alumina, specially treated clays, chro 75 ployed in Example 1 was charged to a reforming
unit operating at a maximum tube metal tem
350 to 500 lbs/sq. in gauge were observed to give
perature of 1000o F., 500 lbs/sq. in. gauge pressure
the best results in the particular thermal oper
and under fiow conditions such that 29.2 per cent
ations described.
by weight of the charge was converted into hy
While the present invention has been described
drocarbons of diiîerent boiling range. The prod
with relation to the alkylation of butylenes with
uct from this reforming operation was debuta
isobutane, it is to be clearly understood that other
nized and a fraction having a 57.6° A. P. I. grav
oleñns and other isopara?lins besides those men
ity, a boiling range of 108-394" F. and a C. F. R.
tioned may be used with equal success.
octane number of 88.4 was obtained.
The nature and objects of the present inven
Besides the large increase in octane number
tion having thus been fully described and illus
resulting from this operation, the gases segre
trated, what I desire to claim as new and useful
gated by distillation of the reformed product con
and to secure by Letters Patent is:
tained 1.8 per cent by weight of ethylene, '1.5 per
A process for converting products resulting
cent by Weight of propylene, 23.1 per cent by
from the alkylation of isoparaflins with olefìns
weight of butylenes and 14.2 per cent by weight
into materials of higher octane number and ma
of pentylenes. It was found that the quantity
terials of a less saturated nature which comprises
of gasoline in the charge stock of the reforming
reforming an alkylate fraction boiling above 300°
operation was only 54.5 per cent by volume while
F. at temperatures between 750° F. and 1100° F.
the reformed product contained, in this particu
and at pressures between 100 pounds per square
lar instance, 57 per cent of gasoline.
20 inch gauge and 600 pounds per square inch gauge
In operations such as those described in Exam
for a time suiñcient for production of a product
ple 1, the amount of gasoline in the reformed
lower molecular weight and boiling point than
product was increased to 72.2 per cent. While
the charge to an extent of not substantially more
the conversion of the heavy alkylate is increased
by raising temperatures and pressures, it is at the m Cil than 30% by weight of said charge, and recover
ing by distillation of said product oleñns and a
sacriñce of gasoline constituents as evidenced by
high octane number substantially saturated fuel.
the data. Operations at lower temperatures of
about 950° F. and pressures in the range of about
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