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Патент USA US2410891

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Nov. 12, 1946.
R. N. MEINERT E'rAL
2,410,891
PROCESS FOR IMPROVING NAPHTHA
Filed Dec. 8, '1944
._u«ndordáuzn
Richard
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'3ra venters
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,f
ze Jr
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Clbbotneq
2,410,891
Patented Nov. 12,1946
` UNITED STATES IkPATENT -oFElcE
rRocEss Fon IMPRovrNG NAPHTHA
Richard N. Meinen, Westfield, and Pnuetus n.
Holt, 2nd, Summit, N. J., assìg'nors to Standard
0il Development Company, a corporation of
Delaware
Application December 8, 1944, Serial No. 567,278
2
Our present invention relates to improvements
in the catalytic-reforming of naphthas in a “iluìd"
catalyst process in which a heat .balance is main
tained in the system by controlling coke forma
’ tion and the ratio of hydrogen which is recycled
with respect to the naphtha fed to the system, all
of which will more fully appear hereinafter.
In catalytic cracking in a system involving a
reaction zone and a regeneration zone, it has been
proposed to supply the amount of heat necessarir 10
and molybdenum oxide or chromium oxide. The
molybdenum oxide or the chromium oxide which
comprises 8 to 12 per cent of the total composi
tion is the active component whereas the zinc
spinel is the carrier or spacing agent. We have
found that this catalyst, particularly when em
ployed in the process maintained under relatively
low pressures, not only converts naphthenes to
the corresponding aromatic by dehydrogenation
but also converts parafiins to aromatics. Hence,
it is possible by our process to convert a virgin
for the endothennic reaction of cracking by burn
naphtha having an octane number of, say, 40
ing the cokev formed during cracking in a re
CFR to a product having an octane number of
generation zone. It is not possible to maintain
from 85 to 100 on the same scale, in good yields.
such a system in heat balance without the use of
coolers and/or heaters, because there is no varia 15 In the accompanying drawing we have shown
diagrammatically apparatus elements in which a
ble at a given conversion of oil to gasoline, since
preferred modification of our invention may be
the amount of coke formed is fixed by conditions.
carried into practical eiîect. Similar reference
In catalytic reforming we have found that the
characters refer to similar parts.
reforming (endothermic) reaction may be main
tained in heat balance with the regeneration 20 Referring in detail to the drawing, a West
Texas virgin naphtha, in the example we have
phase (exothermic) by adjusting a variable,
namely, the quantity of hydrogen used in the
chosen to illustrate our invention, is introduced
into the system through line I. This naphtha is
process, thereby increasing or decreasing the
at a temperature of around 400° F., having been
amount of coke formed. To illustrate, suppose
pre-heated by heat exchange with hot products
that for a given degree of reforming it developed
in a subsequent portion of the system according
that more coke was formed on the> catalyst than
that required when burned in the regeneration
to known means (not shown). The feed is mixed
with a hydrogen-containing gas as its enters the
phase to sustain the reaction phase, then the coke
formation may be reduced by increasing the
system, the .purpose of the hydrogen being to di
catalytic reforming of naphthas in the process in
which there is a productive phase and a catalyst
in suspension by the vaporized naphtha in the
quantity of hydrogen feed to the reaction zone 30 rect the course of the reaction as previously indi~
cated, particularly with regard to the formation
f which has the eñ'ect of reducing the amount of
coke formed in the reaction phase and burned in
of coke which is unavoidably formed in an op
eration of the type here involved. 3 is a catalyst
the regeneration phase. On the other hand, ifit
regenerator andl from 3 we withdraw through a
so happens that the amount of coke produced on
the catalyst in the productive phase is less than 35 standpipe 4 controlled by a valve V a quantity of
powdered catalyst which is discharged into line- that required when burned in the regeneration
I, where it admixes with the naphtha feed and
phase to sustain the endothermic reaction of the
y productive phase, then the quantity of coke being
the hydrogen, and due to the fact that it is at a
temperature of about 1100“ F. it causes vaporiza
formed may be increased by reducing the quan
40 tion and super-heating of the naphtha. to a tem
tity of hydrogen feed to the reaction zone.
perature of about 950° F. The catalyst is carried
'I_'he object of our invention is to operate with
hydrogen into a delayed settler reactor 5. Within
the reactor the gas or vapor velocity is main'
regeneration phase under operating conditions
such that the system is rendered internally heat 45 tained within the limits of from about 1/2 to i0
ft..per second, preferably from 1 to 2 ft. per sec
compensating without resort to the use of coolers
ond, depending upon the particle size of the pow
and/or heating means.
dered catalyst. Ordinarily, the catalyst has a
>A more specific object of our invention has ref
particle size of from about 100 to 400 mesh, with
erence to controlling the amount of coke which
is formed on the catalyst during the catalytic re-> 50 a particle size of about 200 mesh .being preferred.
forming of naphthas in the presence of _added hy
The result of the flow conditions and the particle
drogen.
size within the reactor 5 is to form a dense sus
„
’
We have found that the catalyst best suited for
reforming naphthas is one consisting of a zinc
pension of catalyst in reactants which will have
an upper dense phase leve1 at L, depending on
_ alumina composition commonly called zinc spinel 55 the weight ratio of -catalyst to oil in the reactor,
2,410,891
3
or the amount maintained therein, because as will
subsequently appear, catalyst is being continu
ously withdrawn from the reactor to be regen
the case of the reactor, a catalyst disengaging
erated. We shall set forth, hereinafter, tables '
containing operating conditions within the re
off pipe 4 as previously indicated and the cycle
is repeated.
We have thus described generally a method of
actor.
space.
The regenerator catalyst issues through draw
The reactants pass through the dense phase
carrying our improvements into en’ect. We do
of catalyst into the space S above L where the
not claim novelty in the iluidized type of opera
amount of catalyst suspended in the vapors de
tion we have described but as previously indi
creases sharply upward due to the settling out of 10 l'cated in the manner of maintaining the system in
the catalyst and then the vapors pass through
heat balance without the aid of extraneous equip
one or more centrifugal separators C disposed
ment and utilities. To illustrate this proposition,
in the top of the reactor where entrained cat
we direct attention to the fact that where, say,
alyst ñnes are substantially separated from the
the temperature of the catalyst in the regener
feed vapors and returned by-a dip pipe D (or 15 ator is 1100° F. and that in the reactor 900° F.
it is desired to convert virgin naphtha to gasoline
dip pipes) to the main bulk of the catalyst. 'I'he
reaction products and hydrogen eventually exit
having an octane number of 85, we ñnd that
from the reactor through line i0 and then pass < about 2000-3000 lbs. of catalyst must be cir
to a puriñcation and hydrogen recovery system
culated to the reaction zone per 100 lbs. of oil fed
(not shown) for recovery of desired products and 20 Where the incoming feed is at a temperature of
return of hydrogen to the reaction zone. It is
400° F. (that is, feed in line l about to be mixed
deemed unnecessary to describe the purification
with hot catalyst). This means We must Ben
`recovery of the desired products since that is well'
erate in the regenerator l 36500 B. t. u.'s. It will
understood by those who are familiar with the
be understood that this is a specific example il-art.
25 lustrating our invention and is not to be taken
As previously pointed out, .during the reform
as limiting thereon for, obviously, different condi
ing of the naphthas, coke is unavoidably de
tions will require a different amount of coke to
posited on the catalyst and therefore it is neces- v
be deposited on the catalyst for burning to supply
sary to remove this coke to maintain the catalyst
the heat for the system. However, we set forth
inthe below tables a full statement of conditions
in an active condition. To this end, therefore,
we withdraw catalyst continuously through the
in the reactor which we have found to give the
standpipe I2 carrying taps t and controlled by
desired results.
valve V. As is well known the taps t are dis
Table I
posed in the standpipe I2 for the purpose of in
jecting a small amount of gas which may be hy
Conditions giving good results:
drogen, steam- or other inert gas, into the down
Temperature ______________ __°F___`- 850-1l00
fiowing catalyst for the purpose of maintaining
Pressure _________ __lbs. per square inch-- 0-400
the same in a fluidizedv condition. The catalyst
Lbs. of catalyst per 100 lbs. of oil per
discharges into an air stream I4 in which it forms
hour fed to the reactor__________ __ 500-4000
a suspension which is conveyed to regenerator 3. 40
Table II
The catalyst forms in the regenerator 3 a dense
suspension having` an upper level at L’ in the
The preferred conditions are:
regenerator by maintaining the gas flow rate
therein of the same order as those previously
mentioned in connection with the description of
the operation in reactor 5. The catalyst enter
ing the regenerator 3 is at a temperature at
around 900° F. but during the regeneration
Temperature ______________ __° F____ 920-980
Pressure _________ __lbs. per square inch..- 15-50
Lbs. of catalyst per 100 lbs. of oil per
hour fed to the reactor__________ __ 2000--3000`
In addition to the conditions set forth above,
the real gist of the present invention as previous
wherein the coke on the catalyst is burned, the
ly indicated has to do with controlling the quan
temperature is increased to about 1100° F. As in 50 tity
of coke which is formed on the catalyst dur
the case of the reactor above L’ there is a
ing
the
reaction. If the temperature in the re
sparse phase S1 wherein the concentration of
actor 5 tends to be decreased below the desired
catalyst in gas sharply decreases upward due to
value, immediately the quantity of hydrogen feed
settling out of catalyst so that eventually it con
to the reactor is reduced, thereby permitting the
tains only theflner portions of the catalyst. The formation of additional coke on the catalyst,
gas containing the fines is then passed through
which additional coke when burned in regen
one or more cyclone separators C1 wherein the
erator 3 will, of course, supply an additional
catalyst fines are substantially removed, permit
quantity of heat which would be absorbed by the
ting the issuance of the regeneration fumes from
catalyst and returned to the reactor to correct
regenerator 3' through line 20 substantially freed 60 the unfavorable temperature condition therein
of catalyst. Of course, it will be understood that
tending to take place. Of course, the actual
the sensible heat contained in the regeneration
amount of hydrogen which is fed to the reactor
fumes is preferably, in at least part, recovered
per barrel of oil in order to maintain the desired
by causing the passage of the hot f es through
conditions herein enumerated will depend on the
heat exchangers, waste heat-boilers, and the like. 65 feed stock. Generally speaking, the amount of
‘This is accomplished in equipment not shown.
hydrogen is within the range of from about 1000
Thus, for example, as previously indicated, the
to 4000 cubic feet measured under standard con
cold oil entering the system may bepre-heated
ditions per barrel of oil. But as previously
by heat interchanging with these fumes or with
pointed out, it may be and often is necessary to
the hot vapors in line I0 according to known 70 change the ratio of hydrogen to oil to accommo
means. vThe regenerator is provided with a dip
date a particular feed stock, or the same feed
pipe D1 which serves to return catalyst separated
stock as a catalyst gradually decreases in ac
from the gas in separator C1 and returned to the
tivity during long-continued use. It is, of course,
main body of catalyst below L1. The space S1 be
impossible to set forth numerical values defining
tween L1 and the top of the regenerator is, as in 75 every possible set of conditions but _we may indi
2,410,891
cate the amount of hydrogen necessary by refer
ence to the following guide:
’
Let us assume that the plant is operating in
the reforming of a West Texas virgin naphtha
under conditions generally speciñed in the above
tables and that for every 100 lbs. of oil fed to the
system there is formed 4 lbs. of coke, that is to
say, the system is producing high octane gasoline,
6.
oxide and chromium oxide, maintaining a tem
perature of from 850 to 1100° F. and a pressure
of from about 15-50 pounds per square inch
within said reaction zone, permitting the react
ants to remain resident in the reaction for a sufficient period of time to effect the desired conver
sion, continuously withdrawing a reformed naph
tha. from an upper portion-of said reaction zone,
same gasoline having an octane rating of 85;
that the temperature inthe reaction zone is 950° l0 continuously withdrawing the catalyst fouled
during the reaction from said reaction zone at
_F. and that in the regenerator 1100“ F.; that
a lower point thereof, mixing said withdrawn cat
there is fed to the reactor 30 lbs. of catalyst per
alyst
with an oxygen-containing gas and con
pound of oil; and ñnally, that there is fed to the
ducting it to a regeneration zone where it is
reactor.2000 cubic feet of hydrogen per barrel
formed into a lower dense phase suspension and
of oil. It then develops that the temperature in
an upper dilute phase suspension of said pow
the reactor tends to decrease. In that situation,
dered catalyst in said oxygen-containing gas,
the amount of hydrogen fed to the reactor is im
permitting the catalyst to remain resident in the
mediately lowered, say, to 1500 cubic feet of hy
regeneration zone for a suflicient period of time
drogen per barrel of oil, which lowered hydrogen
to eiîect the desired regeneration, continuously
feed will 'be reñected in a greater amount of coke
withdrawing catalyst from a lower portion of said
formation so that the coke rate rises, say, to 5
regeneration zone, returning said regenerated
per cent by weight on feed. When this catalyst
catalyst directly to the reaction zone and main
is withdrawn from the reactor and regenerated,
taining the reaction zone at reaction tempera
it will of course liberate a greater quantity of
tures without employing extraneous utilities by
heat than the preceding portions and when this
additional increment ofvheat contained in the 25 increasing the amount of hydrogen fed to the re
action zone as the temperature therein tends to
catalyst is delivered back to the reaction zone it
rise and, conversely, decreasing the amount of
will counteract the tendency of the temperature
hydrogen fed to the reaction zone as the tem-1l
therein to decrease. As previously indicated, it
perature therein tends to recede, thus forming
is diilicult to give numerical values for all possible
types of feed, for they may include virgin naph 30 that amount of carbonaceous material on the
catalyst during the reaction so that when the
thas, cracked naphthas, or mixtures of the two.
catalyst is regenerated in the regeneration zone,
However, our experience has been that the coke
formed on the catalyst should amount to from
the heat released and absorbed by the catalyst
3 to 7 weight per cent of the oil feed with the 35 is adapted to maintain the reaction. zone at the
coke formation amounting to 4 per cent based on
desired temperature when the regenerated cat
feed giving good results.
'
‘
, .
alyst is returned to the reaction zone.
Numerous modifications of our invention may
2. 'I‘he method set forth in claim 1 in which
be made by those familiar with this art Without
2000 to 3000 pounds of heated catalyst per one
departing from the spirit thereof.
»
40 hundred pounds of oil are fed to the reaction
What we claim is:
zone each hour, where the temperature of the in
1. A continuous method for reforming naph
coming oil is about 400° F. a'nd further, in which
thas which comprises charging a mixture of a
the amount of carbonaceous material formed on
hydrogen-containing gas and a petroleum naph
the catalyst in the reaction zone is between about
tha to a reaction zone containing a lower dense 45 4 to 5 pounds per one hundred pounds of oil fed
phase suspension and an upper dilute phase sus
to the reaction zone.
pension of powdered catalyst in gasii‘orm re
3. The method set forth in claim 1 in which
actants comprising the naphtha undergoing re- .
the catalyst consists of a major portion of zinc4
forming, the said catalyst consisting essentially
spinel and a minor portion of chromium oxide.
of a zinc spinel carrier supporting one of the class 50
RICHARD N. MÍEUI‘IERT.
of group VI oxides consisting oi’ molybdenuml
PHILEI'US H. HOLT, 2nd.
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