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Патент USA US2408551

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Oct. 1, 1946.
H. S, BLOCH
'
Iso'MERIzATI'oN oF NORIALLY LIQÍJIDA mRocARBoNs
2,408,548
Filed Da_c. 10, 1942
.wmwäY
_Her/z az îälocá, , l
Patented Oct. 1, 1946
l 2,468,548
"UNITED
PATENT oFFlcE ¥
.
.
A
2,408,548
k
„IsoMERIzATIoN or NORMALLY LIQUm
'
"
VVHrDRooARßoNs
’Herman S. Bloch, Riverside, Ill., assignor to Uni
- ycrsal Oil` Products. Company, Chicago,> Ill., a.
' corporation of Delawarek
„Application December 10, 1942, Serial No. 468,496
commen (ci. 26o-683.5)
l
.
The _present invention relates'to the‘catalytic
,
,
2
velocity by a factor of the density of the charge):.
isomerization of saturated hydrocarbonsl in- the
Although the reason for this particular effect
substantially liquid` phase." More specifically, iti
is not clearly understood, itis probable thatr _at
deals with a novel method wherein the catalyst
increased linear velocities, a scouring action is
isiutilized toits maximum efii'ciency under opti
robtained which constantly" cleans the catalyst
mum conditions ofpperation.y
`
-
'
The present invention is applicablevn'ot only
to the isomerization of individual saturated'hy
drocar-bons such as butane, pentane, hexane, hep
tane, cycloheXane, etc., but'also to hydrocarbon
mixturesk containing these-v compounds
sub~
stantial-'percentages such as straight ïrun gaso
lines and other fractions. Itr is particularly
adaptable to the isomerization of low octane num
ber gasoline fractions containing' the usual
amount 'of parafñnic andnaphthenic hydrocar-r
bons; The‘resulting product from the isomeriza~
tion'of these fractions has a. high antiknock value
and> anA exceptionally high‘lead susceptibility. `
surfaces and permits the reactants to continually
contact active catalystiparticles.
One of the advantages of the present inven
tion- is `its increased flexibility over thermethods`
of operation previously disclosed in that the linear
velocity can be varied.f over» Wide ranges- While
maintainingY the actual charge rate of fresh feed
tothe reaction zonesubstantially constant. For
example, in a once-through operation for a given
reactor. size the linear velocity and residence time
of the hydrocarbons in the reaction zone are di
rectly proportional. to. the space Yvelocity of the
fresh feedv being charged.y However, in my. im-`
proved operation, the. linear velocity of the hydro
Princi'pally, the present invention comprises
carbon through the same sizey reactionv zone is a
contacting a, granular bed' of a metallic 4halide
function> of both .the space velocity of the fresh
feedand. the. combined feed ,ratio which is de
pendent uponv the recyclev rate being used. Itis
possible to- obtain various linear velocities through
isomeri'zingcatalyst with a mixture of saturated
hydrocarbons and"hydr`ogen.halide" in >afcycliç
, flow operation under speciñc'operating conditions,
" withdrawing» a portion of the isomerized 'product
the reaction zonewithout .changing the residence
and .commingling the remaining, portion of .the
time or spacervelocity of the fresh. feed.
product from the reacting zone with the fresh
therefore obvious. that. in> a- once-through opera
It is
tionJ'f-'the optimum residence time. does not coin
eide, with the‘optimum linearvelocity, it is neces
of fresh feed being substantially equivalent to the
30 sary to operate at some intermediate value of
amount of isomerized product withdrawn.
residence timer and linear velocity which will give
,y Isomerizing- catalysts Which maybe effectively
the best average results;v However, When operat
utilized in the present. inventionwill» comprise
ing inv accordance With the present invention, the
metallic halides of the Friedel-Crafts type which
possess some isomerizing activity andwhich pref.
optimum residence time may be maintained and
rerably- possess a loW solubility in the hydrocarbons - the linear velocity independently varied by vary
ing the combined-'feed ratio, thereby obtaining
under the particular conditions of operation. Ify
the solubility of the metal halides is appreciable,
the most efficient operationA possible.
'
obviousl changes may be made, in the operating
The yfollowingr formulae are introduced to fur
procedure whereby> the hydrocarbon products
ther eXpIainthe advantages of the` present» proc
from the system may be separated from.dissolved
ess over the well-known operations».
These
formulae are applicable to a liquid phase isomeri-`
salts-and the latter,¿in solution With .the recycle
hydrocarbons, commingled with the. fresh charge. ' zation- process `and Willgive acomparison of the
íiexibilities'of a once-through operation and the
The operating, variables in this isomerization
cyclic operation of the present invention in re
process include the temperature, space velocity
spect. to a given reactor size.
(liquid volumes. of charge per _volume of catalyst
The ñrstform-ula which applies is
bed per hour), linear velocity, hydrogen. halide
concentration, hydrogen concentration, and the
Afeed being introduced into the system, the amount
residence timeof the hydrocarbons inthe kcata
lytic 'zoneÍ
.
I
v
»
`¿
>
1
I have. found that, withthe. other conditions of 50
operation heldsubstantially constant, the-degree
of fisomerization Will be iniiuenced to> aî consider
Where
,
L=linear velocity
‘
:space'velocity of fresh feed’
_
C=combined feed ratio, defined as the amount
able extent by the linear velocityof the'- reactants
>of' recycleî plus the amount> of freshv feed divided
through;v the bed of granular catalyst (or 'bythe'
massfvelocity,- >Which differsiï from ’the linear» 55 'v' bythe amount 'offr fresh: feedî per unit 'time`
2,408,548
3
4
.
saturated hydrocarbons which comprises contact
f1=a function involving the reciprocal of the
ing said hydrocarbons in the presence of hydro
cross-section of the catalytic reactor
gen chloride with an aluminum chloride isomer
izing catalyst disposed within the reaction zone,
withdrawing and recovering a portion of the
emergent products from said reaction zone, and
commingling Athe remaining hydrocarbons having
Where
T=average residence time in the reaction zone,
defined as the volume of free space in the reac
substantially the same composition as the with
drawn portion with the hydrocarbons being
charged to the reaction zone.
The invention Will be more fully explained by
a. description of an operation in connection with
tion zone divided by the volume of fresh feed ‘
per unit time.
fz=a function involving the percentage vof free `
space in the catalyst bed.
the accompanying diagrammatic drawing which
A
Substituting Formula 2 in Formula 1 the follow
ing is obtained:
1
illustrates in conventional side elevation one type
15 of‘apparatus in which the objects of the invention
may be accomplished.
Referring to the drawing a saturated hydrocar
bon charge, for example, a gasoline fraction of
(3)
about 210° F. end-point containing saturated C5,
In a once-through operation the combined feed 20 C'e and Cv hydrocarbons is introduced through
line I containing valve 2 and is commingled with
ratioA is equal to unity and Formula 1 is then
recycled hydrocarbons obtained as hereinafter
equal to
-.
set forth, and the mixture transferred by pump 3
(4)
L=Í1(S)
through line 4 containing valve 5 into heat ex
25 changer 6. During the passage of the hydrocar
or Formula 3 is equal to
bons through heatgexchanger 6 they are raised
to a temperature sufficiently high to compensate
1
<5)
L-fa T)
for heat losses when transferred through line 1
containing valve 8', and to maintain the desired
It is evident from the above formulae that it is
impossible in a once-through operation With a 30 temperature in reactor 9. Steam is introduced
into exchanger 6 through line 24 containing valve
25 and the condensate is withdrawn through line
26 containing valve 21.
given reaction vessel to independently vary the
space velocity and the linear velocity.
In operating in accordance with the cyclic ño-W
The necessary hydrogen chloride is introduced '
method herein disclosed it can readily be seen
through line I9 containing valve 2D into com
that the linear velocity can be varied over Wide 35
ranges while holding the space velocity of the
fresh feed constant by varying the combined feed
ratio. This permits conducting the operation at
the optimum space velocity of fresh feed andthe
optimum linear velocity.
~
pressor 2| which discharges through line 22 con
taining valve 23 into line 1. The amount of hy
drogen chloride added to the hydrocarbon charge
is dependent primarily upon the actual residence
40 time of the hydrocarbons Within the reaction
I have found that the speciñc conditions of
temperature, hydrogen chloride concentration,
space velocity, residence time and linear Velocity
to be used with a> given charging stock in con
junction with the cyclic flow operation fall Within L
zone. I have found that the maximum hydrogen
chloride as weight per cent of the hydrocarbon
charge varies with the residence time of the hy
drocarbon in the reaction zone in accordance
with the following empirical formula:
well defined ranges depending primarily upon the
isomerizing catalyst being used. It is desirable
that the temperature of the operation be suñî
ciently low so that the solubility of the catalyst
Hydrogen chloride c0ncentration=
in the hydrocarbon is practically negligible, since `
As is evident‘from the formula, the maximum
hydrogen chloride concentration decreases with
the operation is greatly simplified thereby. When
using an aluminum chloride isomerizing catalyst,
.
Y
240
residence time in hours
increases in residence time.
Although not essential for the effective conduc
below about 150° F. The minimum space Velocity
tion of the reaction, I have found that the addi
which may be utilized is about 0.4 volume of com
tion of hydrogen has a beneficial effect in de
bined feed per volume of catalyst bed per hour.
creasing the amount of side reactions and in
It is difficult to ascertain the maximum permis
creasing the octane number of the isomerized
sible space velocity, since these space velocities
product. The amount of hydrogen introduced
will be governed somewhat by the type of equip
into the reaction Zone depends somewhat on the
ment being used. However, I have found that 60 catalyst and the temperature maintained in said
space velocities in excess of 50 do not give any
reaction zone. For example, when aluminum
appreciable improvement in results. The resi
chloride is used at temperatures of about 85° F.,
dence time will be dependent primarily upon the
the beneficial hydrogen pressure in the system
space velocity of the fresh feed but will always
lies within the approximate range of 25 to 125
be below l5 hours. The linear velocity will be
pounds per square inch. At higher and lower
dependent upon the size of equipment, combined
temperatures, similar optimum hydrogen pres
feed ratio, etc., but will always be in excess of
sure ranges exist.
Y
about 20 centimeters per hour. I have found that
The hydrogen is introduced into the reactor
improved results are obtained with increases in
through line I4 containing valve I5 into com
linear velocities in the stream line fiow region
pressor I6 which discharges through line l1 con
and it is to be expected that further improve
taining valve I8 and is commingled with hydro
gen chloride and hydrocarbon in line 'I and the
ments will be obtained Yin the turbulent flow
regions.
total mixture introduced into reaction zone 9.
In one specific embodiment the present inven
During the isomerization reaction, a small
tion relates to a process for the isomerization of
amount of the hydrocarbons react with the
the
isomerization
temperature ‘ is
maintained
zgflosgses;
51
6.
catalyst to form acomplex commonly‘termed;
sludge.. >This sludge is> periodically-Withdrawn
from. the> reactor rvthrough~ line 28Y containing?
valve 29.
The solid granular catalysts l* disposed. Within.
reactor Sema'y comprise aliuninum: chloride: zine
chloride, zirconium chloride and iron- chloride,
uct'is: only about 67.1` and? .the 1oss.due'ìtof.gas
formation is about 6.2 per cent.
It is obvious from a comparison` of the above
results that the isomerization of saturated hy
drocarbons in the cyclic flow operation process
has< manyf advantagesy overl the ordinary once
throu‘gh operation.
either alone ori in admixture~ withv one.` another.
The temperature-Withinreactionzone*9y is de'
termined primarily bythe extent of conversion.
desiredI and by the solubility of Vthef catalyst.: in
the hydrocarbons being charged. VIt' is preferable
that the temperature bef suiiicien‘tly low to: pre-`-Ã
vent'any'substantial carry-over of. the- catalyst
in- solution. ofthel hydrocarbons' leaving.' thezre
action zone. A portionfofithe hydrocarbonrleav
ing vreaction zone 9- through line> l0 vis Withdrawn
through: line ~I I and is recovered asv a. product
ofv the reaction. The hydrogen. chlorideV and
hydrogen may be’ removed in subsequent frac-'
' tionating- equipment 4and recycled tothe reaction
Example III
Y
A debutanized naphtha containing equal vol-y
umes of pentanes, hexanes and heptanes having'
an octane number ofV 63.2 is passed through the
same reactor used in. Example I. under similar
conditionsof temperature andY hydrogen chloride
concentration with. a residence time of 12. hours,
com‘binedfeedl space velocity of 1.8 and .alinear
velocity of 90 centimetersfper hour. The rateoff
fresh. feed addition is about 25 cubic centimeters
per ‘hour giving a. combined feedv ratio of about
>36. The debutanized isomerate' hasa 9.9'Reid.
vapor-pressure and a clear octane number of 80.8
Zone. The remaining portion of the> isomerized
motor method. The octant number is increasedI
product is' withdrawn through line .I 0 andiline
to ‘94.7 motor method byl the addition of 4-cubic
l2 containingvalve' |3- and is"commingledlin line
centimeters ofethyl fluid perigallon of isomerate.
4 with the fresh feed being, introduced to they 25
process.
y
'
The following examples are introduced tosh'ow'
the improved results- obtained when operating in,
accordance with the present invention.
The effect'y of varying thespace velocity of'th’e>
combined!feed»Whilev holding'the other condi@
tions of’ operationk constantïis show-n in the fol#
30 lowing- example. «
Example I
Al heptane fraction‘having‘ aboiling rangeV of’
An acid treated gasoline-y fraction havingl a
Y 18S-2129
and an octane-'number' of 53.4 is' isom-V
erizedv at room temperature with-*av hydrogenv
chlorideÍ concentration ofï"15'- weight'per cent 'of
the change. The'fresh feed' spaceßvelocity is 0.1
throughout' the' various' tests.V TheV depth in'
disposed in- a reaction tube having a cross
cross-'sectional areaE ofthe catalyst bed', the' comsectional areav of 10 square'centimeters'. Hydro->
gen chloride is added into the reaction zone irr- ` bined’feed ratiolv and the rate ofrfresh feed charge
arel adjusted to maintain alinear velocity of
an amount equal to 15 Weightper cent 1 of the
hydrocarbon charge. A- portion of thejreactionY
100" centimeters per hour; and`l ai residence timel
of ôfhours yWhile' varying the combined feedspace
products emerging from the reaction zone is*- con
VelOCÍÍìyíA The’fÓHOWÍIl‘g" 'results V.areA obtained:
tinually withdrawn and the> remaining portion>
recycled to the fresh‘feedxinletj Anamountiof
fresh feed equivalent ’to-the.` amount of rproduct A35
boiling range of 186 to 212.o F. andanoctane
number of 55.5 is passed at> room temperature"
through 500 cc. of granular aluminum Achloride-
Withdrawnis continually introduced. The-space
velocity of. the freshfeed measured as> volumesv
of hydrocarbon> per volume of catalyst bed‘zperi
hour is about 0.1.; the space velocityîofv 'the com@
bined feed is 2. The free space>V in the reaction;
' Combined feed'spacc-velocity
1 debutanized
product
motor’
method
zone is 'about 800 cubic centimeters. The> lineari
velocity of the combinedfeed is equivalent'to- 100.A
centimeters per hourï giving a combined feed’
ratio of` 20. . The actual residence timef offthe.
fresh feed in the reaction> zone is about 6 hours.Í
The octane number of the isomerized productY
is 69.4,V an improvement'of 13.9v octane» numbers
over the original hydrocarbon charge. ‘Thefloss
due yto gas formation is exceptionally low,
amounting to only' about 4% by Weight' of the
charge.
'
It is‘apparent fromy th'e above data" that at
combined feedrati'os above 0.6 the octane'num
bervv of the isomerized product is substantially'
constant. However, at a' space> velocity of 0.3'V
thej octane numberI is‘ considerably lower. I have
determined- that the criticahminim‘um space
Velocity’ of the" combined feed for optimum re’
'
sults is ab'out'0í4..>
Eœample’II
. ,
Example' AV n
The results of the following’ onceethroughop
eration undery comparable conditions are-indica-~
tive when compared with the results'above of the’
improvement obtained when operating in ac-~vv
cordan'cve with the'present invention. 'I'he fresh
feed space velocity, temperature, hydrogen chlo
ride concentration and residence time of the
fresh feed are held as in Example I.
The linear Y '
velocity because of the decreased volume of hy
drocarbon reactants entering the reaction zone,
is considerably less being about 5 centimeters per
hour. The octane number of the resulting prod
y'I‘l'ie »effect of varyingjhydrogen pressure-While
holding-- the vothery operation- variables constant y
is shown inv theY following example:
The heptane’fraction'used' in Example IVA is
isomerized in the same reaction Zone used
Example I at room temperature with the hy
drogen chloride concentration of 15 Weight per
cent of the charge. The operation conditions
are a fresh feed space velocity of 0.05, a linear
velocity of the combined feed of 45 centimeters
per hour and a residence time of the reactants
of 12 hours. The combined feed ratio is 18.
2,408,548,
7
‘ The following results are obtained byvarying
the hydrogen pressure:
.
»
’
»
'i
_.
the reactionV zone a linear velocity for the com
bined feed of at least 20 centimeters per hour, a
'
O ctane
number of
CTL
method
residence time not in excess of about 15 hours
and a space velocity not below about 0.4 meas
ed as Volumes of combined feed per volume of
catalyst bed per hour. Í
3. Aprocess for the isomeriaati‘on of a paraf
finie" charging stock which comprises com
`Hydrogen pressure, pounds per square inch
`
8.
the'products in the combined feed to provide in
" '
10
5.
8.
From the above results it is apparent that
under these particular conditions of operation
the optimum range of hydrogen is about 25 to
about 125 pounds per square inch.
mingling with said charging ‘stock a recycle stock
formed as hereinafter set forth, passing the re
»sultant combined feed together with ahydrogen
halide and at isomerizing temperature through
a reaction Zone containing a catalyst bed com
prising an aluminum `halide and therein effect
ing substantial isomerization of the charging
stock, removing the resultant products from said
Zone and separating the same into portions of
like composition, withdrawing one of said por
tions from the process, commingling another of
20
tion and examples, although neither section is
said portions with the parafdnic charging stock
intended " to unduly limit its generally broad
as said recycle~ stock, the amount of charging
smpa- I,
»
v
. ,
stock'ín the resultant combined feed being sub
' Iclaim‘as my invention:_
»
stantially equivalent to the amount of said por
i 1. VA process for the isomerization of a satu
tion of the products withdrawn from the process,
25
rated hydorcarbon. charging stock which com
and regulating the amount of said other portion
prises commingling with said charging stock a
of the products in the combined feed to provide
recycle-stock formed as -hereinafter set forth,
in the reaction Zone a linear Velocity for the
passing the resultant-,combined feed at isomer
combined feed of at least 20 centimeters per
Thev novelty and utility of the present'inven
tion are evident from the precedingspeciñca
izing temperature through a reaction Zone con
taining a catalyst bed comprising va Friedel
Crafts metal halide isomerizing catalyst 'and
therein effecting substantial.isomerization of the
charging stock, removing the resultant products
from said zone and separating the same into»
30 hour, a residence time not in excess of about 15
hours and a space velocity not below about 0.4
measured as volumes of combined feed per vol
umeof catalystbed per hour.
’
’
4. A process for the isomerization of a paraf
finic charging stock which comprises corn
portions of llike composition, withdrawing one of 35. mingling with said charging stock a recycle stock
said portions from the process, commingling an
other of said portions-with the saturated hydro
carbon charging stock as said recycle stock, the
amount of charging stock in the resultant com-l
formed as hereinafter yset forth, passing the re
sultant combined feed togethery with _hydrogen
chloride and at isomerizing temperature through
a reaction Zone' containing a catalyst bed com
bined vfeed being substantially equivalent to the 40 prising’ aluminum chloride and therein effecting
amount of said portion of the products withdrawn
from the process, and regulating the amount ofl
said other portion of the products in the com
bined feed to provide in the reaction Zone a
lineair` velocity for the combined feed of at least
20 centimeters per hour, a residence time not
substantial isomerization of the charging stock,
removing the resultant products from said zone
and "separating the- same into portions of like
composition, withdrawing one of- said portions
from the process, commingling another of> said
portions With the paraffinic charging stock as said
recycle stock,y the amount of charging stock in
the resultant combined feed being substantially
bined feed per volume of catalyst bed per hour. 50 equivalent to the amount of said portion of the
2. A process for the isomerization of a satu
products Withdrawn from the process, and reg
rated hydrocarbon charging stock which com
ulating the amount of said other portion of the
prises commingling with said charging stock a
products inthe combined feed to provide in the
recycle stock formed as hereinafter set forth,
reaction Zone a linear velocity for the combined
passing the resultant combined feed at. isomer
feed of at least 20 centimeters per hour, a resi
55
izing temperature through a reaction Zone'con
dence time not in excess of about 15 hours and
in excess of about 15 hours and a space velocity
not below about 0.4 measured as volumes of com
taining a catalyst bed comprising an aluminum
halide and therein effecting substantial isom
a. space velocity not below about 0.4 measured as
volumes of combined feed per Volume of catalyst
erization of the charging stock, removingr the
bed per hour.
'
resultant products from said Zone and separat
-5. The process as defined in claim 1 further
ing the |same into portions of like composition, 60 characterized
in that said isomerization of the
withdrawing one of said portions from the proc
charging stock is effected in the presence of hy
ess, commingling another of said portions withdrogen.
the saturated hydrocarbon charging stock as
o 6:.y Thev process as defined in claim ‘i further
said recycle stock, the amount of charging stock
characterized in that said isomerization of the
in the resultant combined feed being substan
charging stock is effected in the presence of hy
tially equivalent to the amount of said portion of
drogen.
the products withdrawn from the process, and
.
HERMAN S. BLOCH.
regulating the amount of Isaid other portion of
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