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Патент USA US2408602

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Oct. l, 1946. ~
,
c. H. o. BERG
Y
2,408,600
CRACKING PROCESS`
>Filedsept` 22, 194s
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Regeneration
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BY WMM
2,408,600
Patented oct. 1, 1946
UNITED STATES PATENT OFFICE
GRAC'KING PROCESS
Clyde’H. 0. Berg, Long Beach, Calif., assignor to
Union Oil Company of California, Los Angeles,
Calif., a corporation of California
Application September 22, 1943, Serialv No. 503,345
7 Claims. (Cl. 196-52)
1
2
figure, wherein a catalytic reactor is positioned
This invention relates to the catalytic conver
above a' catalyst regeneration chamber, and a
sion of hydrocarbons, and especially to the crack
continuous solid' stream of granulated catalyst
flows down' through both chambers-l,v the catalyst
moving stream of granular catalyst.
Catalytic cracking processes are known wherein Ul being carried back to the t'opl of the reactor by
ing of petroleum fractions in the presence of a
suspension in a gaseous stream of vaporized feed.
the crackingy is carried~out in the presence of
moving catalysts, and these processes are among
the most efñcient in use today. The. known proc
Referring to the iigure, vaporized and pre'
heated hydrocarbon feed is introduced through
line Iv and control valve 2. In> mixing section
3 this feed' gas is> mixed~ wtih catalyst from line
esses of this nature are of two different types,
namely (l) the fluid type, and (2) the moving
-
bed type. Each of
and disadvantages.
4, and’ carries this catalyst in suspension upward
these has its own advantages
through line 5 and into separator 6-. Here the
gas is separated from thev catalyst and passes-out
through line l.' The catalyst drops through line
3| into hopper 8; and thence downward in a
solid moving, bed' or stream through sealing leg
9 into reactory I0'.
In reactor I0 the catalyst is heatedl by- indirect
V
The fluid- type process employs a powdered or
dust-type catalyst which is blown through the
reaction zone by a stream of feed vapors, and
then is separated from the vaporous conversion
products, and regenerated by being blown through
a regeneration zone by a stream of air.
heat exchange with hot- combustion gases passing
The moving bed type process employs a granular or bead type catalyst, which moves down 20 through tube 26 and obtained byr burning fuel
with air in burnerV H'. The hydrocarbon va
ward as a solid. bed through a reaction zone
pors from line 'l' are introduced- near the bottom
through which a countercurrent stream of feed
of the reactor through lines I2‘and 2-4 and valves
vapors is passed, and then is separated from the
‘l3` and 3l', and are subjected tocountercurrent
vaporous conversion products, mechanically con
veyed to the top of a regeneration zoneV through 25 contact with the flowing' catalyst. The product
vapors' leave the" top of the reactorl through line
which it moves downward in a solid bed through
I4 and valve 3A, which are kept' clear ofV catalyst
which air for regeneration is passed, the regen
by passing the' catalyst down through tubes I5,
which extend. below outlet t4 and thus provide
erated catalystv being separated and mechanically
conveyed> to the top of the reaction zone for re
use.
f
»
30
a disengaging'space.
'
The used catalyst drops from the- lower party of
The fluid processvhas some advantages over
reactor 1'0 through sealing leg 30" into regenera
the moving bed process in simplicity of construc
tion chamber |61 where` it is regenerated by con'
tion of reactor and regenerator chambers, but has
tact with air entering through line 35‘ and valve
disadvantages in diñ'ìculty of separation of the
catalyst from the gas streams, with -attendant 35 36, and-` is cooled by indirect heat exchange'with
a c-ooling medium entering through line I1 and
catalyst loss, and diiiiculty of control of regener
leaving through linev I8.A The regeneration flue
ation temperatures. The moving `bed process has
gases leave through line 25, and the regenerated
the advantage over the fluid process in lower cat
catalyst leaves the bottom’ of the chamber through
alyst loss, more easily controllable regeneration
temperatures and less. difficult catalyst separa 40 conical' section I9: containing baiile 20', drops
through line 2 I' containing shut-off Valve 22 and
tion, but the two mechanical Vconveyor systems in
orifice 23 into line Y4, and repeats 'its cycle. Cat
volved are very expensive to b-uild and maintain
and must be adjusted frequently vto balance the
reaction system against the regeneration system.
alyst lmay be withdrawn from thef'system through
line 28 and> valve 29 or added> to' the hopper 8
A process has now been discovered which has 45 through line 2l.
There are many advantages in the above" de
rthe advantages of both of the above systems with
scribed process over conventional processes. The
out their disadvantages. Briefly the process in
equipment is simplev to' construct and operate.
volves movement of a granulated catalyst in a
There are no" complicated mechanical conveyor
single continuous path, the catalyst being car
rie/d:v from the bottom to the top'öf its path by 50 systems,v and catalyst separation is simple and
suspension in a flowing stream of gas, and'thence
after separation from the suspending gas, flowing
downwardv in a continuous solid moving` .bed
through zones of reaction and regeneration. One
form of 'the îprorcess‘is illustrated in the" attached ,_ 55
eflicient with the preferred granular catalysts.
There is no necessity` for “balancing” of the flow
of catalyst through the reactor.l against the flow
through~ the regeneration. chamber, since both
flows arey part »ofi a» single continuous' cycle. Im
'2,408,606
3
4
processes involving primarily a change in struc~
ture without substantial change in molecular
a desirable preliminary cracking in line 5.
Weight, such as hydrogenation and dehydrogen
Separator 6 may be a conventional cyclone
ation, aromatization, isomerization, and the like.
separator, and the reactor, regeneration cham
ber and auxiliary equipment are of simple de UI By refining is meant4 the conversion of small
troducing hot feed into line I appears to give
amounts of undesirable hydrocarbons or con
sign and fabricated from common materials of
construction. N o baflies, packing, etc. are neces?
sary in themain body of the hopper, reactor, or
regeneration chamber, although they may be
employed if desired.
The regeneration cham
ber may be of multi-tube or multi-coil design
with multiple air inlets and flue gas outlets to
provide very close temperature control if de
sired. Similarly, the reactor may be equipped
with multiple heaters, and multiple feed inlets
and outlets if desired, to control contact time
and temperature to provide either isothermal
operation or operation with the desired tem-_
perature gradient. Multiple tubes may also be
used in place of the single line 5 shown. Baffie
20 is merely a circular shield located centrally
in conical section i9 to prevent the ñow through
the central portion of the regeneration cham
taminants to less objectionable forms, as in the
polymerization of color and gum unstable oleñns,
dioleflns, and the like, conversion of sulfur,
10 oxygen, and nitrogen-containing contaminants
in hydrocarbon stocks to easily removable forms
such as HzS, H2O, NH3 and the like.
I
The hydrocarbon feed stocks may be various
petroleum fractions, such as natural or cracked
gases, natural, crude or cracked gasolines, kero
senes, gas oils, lubricating oils, extracts, or other
products obtained by conversion or extraction of
such stocks; or similar fractions from coal tar,
shale and the like. These may be converted by
the
appropriate treating processes of the pre~
20
ber from exceeding materially the ñow through
the outer portion. If desired, any catalyst fines
leaving with the gases in lines 1, I4 and 39 may
be removed by Cyclones, Cottrell precipitators,
vious paragraph to stable, high-octane gasolines,
specific olefms, aromatics, naphthenes, or iso
parañ'ins, or other desired products.’
As examples of the above processes, a gas oil
fraction from petroleum may be vaporized and
heated to about 800° F., the vapors being intro
duced into line I. These vapors pick up cata
lyst from line 4 and carry the catalyst upward to
settlers or the like. Any small loss of catalyst
separator 6 from which the catalyst flows through
may be compensated for by the addition of new
catalyst through line 21. The effectiveness of 30 the hopper, reactor, and regenerator as pre
viously described. The feed vapors from sepa
sealing legs such as lines 9, 30 and Z‘! may be
rator 6 are introduced at the bottom of reactor
improved by injecting a sealing gas such as
I0 as indicated, being further preheated in line
steam, flue gas, carbon dioxide, nitrogen, and
24 if desired. An auxiliary gas such as hydro
the like into the side of the lines at some point
gen, a light hydrocarbon or an inert gas may be
.or points not too close to either end. This is
introduced into this stream through line 39 and
illustrated in the ligure by the addition of steam
valve 38, if desired, and this gas may be pre
into line 30 through line 40 and valve 4I.
heated to supply any additional heat desired.
In a second method of operation, hydrogen or
a light hydrocarbon gas may be fed through line y
For example, a, propane or butane or lighter frac
_I to carry the catalyst through line 5, and the 40 tion from the product may be preheated to 1100°
F. and introduced into 39 so as to increase the
hydrocarbon feed may be introduced through
temperature of the mixture in line 24 to 900° F.
valve 33 and lines 32 and I2. The gas leaving
to 1000o F. The mixture may then be subjected
separator 6 may be withdrawn through lines 1
to cracking in the presence of the catalyst in
and 39 and valves 31 andv 38, or part or all of
it'may be introduced into reactor I9 with the 45 reactor I0 at substantially atmospheric pressure.
The product may be withdrawn through line I4,
feed, through lines 1, 24 and I2, and valves 31
and fractionally distilled to obtain a gas frac
and I3. In this type of operation it may _be
tion, partof which is recycled through line 39,
most effective to add considerable heat to the
a gasoline of good antidetonation character
gas during its passage through line `24, or to _
heat the mixture in line I2.
50 vistics, a gas oil which may be vaporized andre
cycled to line I, and a residuum suitable as fuel
Although the above methods -are preferred,
oil.
a third method may be employed, wherein con
A gasoline or naphtha fraction may be re
current flow of feed vapors and catalyst is em
formed by a similar process. By operating at a
ployed in reactor I0. This may be done by clos
ing valves 34 and 31 and forcing the feed vapors 55 pressure of l0 or more atmospheres and using
hydrogenV through line 39 rather than a light
entering line i to pass down through separator
hydrocarbon, a product of higher aromatic hydro
6, hopper 8 and reactor I0, leaving through line
I2.
In this method it is notl necessary that line
_9 be a sealing leg. In fact hopper 8 may be
incorporated as an integral part of reactor I0, 60
with no intervening constriction.
The above processes may be employed for
many types of hydrocarbon conversion, includ
ing cracking, polymerization, reforming and re
carbon content and lower olefln content may
usually be obtained.
'
In another mode of operation, flue gases at a
temperature of 2000° F. to 4000° F. may be added
through line 39 to give a preliminary thermal
cracking at temperatures between about 1000° F.
and 2000° F. to the hydrocarbons from line 1.
ñning. By the term cracking it is intended to l 65 Diluents such as inert gases, recycled fractions,
etc., may be added through line 32 to control
include processes wherein there is a scission of
the temperature of the subsequent catalytic re
carbon-to-carbon bonds of the feed hydrocar
action in reactor I0.
`
bons, such as in conventional cracking of various
The above 4operations may also-be used for the
petroleum fractions, as well as dealkylation, de- , .
polymerization, and like processes. By the 70 dehydrogenation of butanes to butenes, and the
>further dehydrogenation to butadiene, in which
term polymerization it is meant to include re
processes it is advantageous to maintain a low
actions involving increases in molecular weight,
total pressure such as atmospheric'pressure, and
such as condensation and alkylation reactions, as
to reduce the partial pressure of _the hydrocarbon
-well as polymerization of oleflnic material. By.
in the reaction chamber to a small fraction of
the term reforming it is intended to include
9,408,600
5
6
one atmosphere, such as.0.1 atmosphere or less,
preferred. but pressure. differences up te .1.0 at»
by the introduction Vof .inert -gases such »as .lille
gas, nitrogen, steam andthe like, added through
mospheres ,or `more may be tolerated .by the ‘use
of‘properly ydesignen sealing :legs 'es the pres,
-sure differential is increased, the-.eiîñeíeney ef the
-lines
I, 32, or 39.
.
w
i
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'
.
Refining processest such as catalytic desulfuri
5
also be carried on as above.
».
seaune ieg must be increased. esfor exemple -bv
lengthening .the leg. er using more »Sealing gas.
The `relative amounts of feed stock, auxiliary
zation Vor hydrogenation Vmay readily be car
ried out according to vthe above: methods, using
hydrogen as the auxiliary gas. Refining of gaso
lines to remove unstable olefins andthe like may
gas `and vcatalyst employed will vary with the re
suits desired. `-As an example however2 .applying
to the aromatization of a crude gasoline ,fraction
.i
at 1.000° F. and 10 atmospheres pressure, thelfeed
may be introduced at a rate Qf l (liquid)- ¿volume
per volume of catalyst @in reactor. Ill) ¿per hour,
hydrogen may be .employed in e retin ef 3000
cubic feet per barrel of (liquid) feed, and the
catalyst may be circulated at a rate -of about >0.5
In all of the above methods in which an aux
iliary gas is employed, these may be introduced
vinto line I instead of feed stock vapors in orderV
to carry the regenerated catalyst up through yline
5, while the feed stock is introduced through ‘line
32. It is also possible to employ the concurrent
volume per hour. The catalyst flow rate ¿is reg
ulated largely. »by the sizeof the 4.orifice 23, `Feed, ,
ilow method described earlier, . `wherein sealing
leg 9 is eliminated and the vapors in line '5 `are
auxiliary ses. and catalyst flow4 rates between
forced down through the reactor.v This method
is particularly »effective when treatingv a gasoline 20 about one-tenth to ten times the above rates may
be employed, yanderen Wider limits may be used
to polymerize unstable gum-formingoleflns, since
the polymers _formed may condense and be swept
in some instances.
out of the bottom'ofy the reactor.
Y
l
l
,
.
Outstanding features of the >process of this in.
vention yas mentioned previously,;are its simplicity
other ,oper
-ations, however, the countercurrentfcontacting is
preferred.
ì Vand the use of a granular catalyst circulated by
As catalysts for the cracking and reforming
suspension in a flowing gaseous stream, followed
by gravitational downward flow in a solid stream.
operations alumina, »silica-alumina rcombinations
and group VI metal oxides such as chromiumand
molybdenum oxides, especially when employed
with a support or carrier such as alumina or other 30
metal oxide gel and the like, are suitable. For
hydrogenation operations, oxides of metals hav
ing atomic numbers between 22 and 30 Tand espe
cially cobalt, nickel and copper, andcombina- -
tions of these with chromium, molybdenum', ti
tanium, Vanadium, and the-like, as mixtures and
as compounds such as chromites, molybd-ates, etc.,
are suitable.
.These may also be employedy on
carriers. For refining cracked gasolines, `active
clays, bauxite, magnesia, fuller’s earth, andgvari
ous oxide gels are suitable. ¿These latter _are also
suitable carriers for the more active catalysts
mentioned above. The invention is of course not
limited to the use of the specific catalysts named.
No difficulty »has been experienced in carrying
granules of the above sizes _up through line 5'.
For example, granules of v12 to 30 mesh have
been lifted over 3_5 feet through a ,1% inch pipe
VVline at a rate of about 400 pounds. per hour by a
_gas stream of about rmvpounds per hour.
In a variation of the process of `this invention,
the regeneration chamber vI6 is placed above re
actor Iû, with sealing leg 30 between and sealing
leg 2| below as usual. Non-combustible inert gas
with or without some air may then be introduced
into line I, the obvious modifications in flow being
employed.
,y
In any of the above systems it is ‘apparentthat
there are vmany variations which may be 1em
ployed.` Fory example the cooling fluid employed in
`regeneration chamber l 6 may also -be employedas
„a heatingy ñuid in reaction chamber IQ. This
The catalysts should be granular, preferably
about 4 to20 mesh in size, although sizes between»
would> necessarily involve a gaseous fluid, or pos
sibly a system of flowing solids such as the cata
about 1 and 60 mesh may be employed in many
lyst iiow system, but would preferably be a liquid
instances, and »where special bailling is employed
such as a molten salt. When the cooling fluid
in the reactork and‘cooler to permit countercur
rent flow of the gases without suspension of the 50 i-s not also used in the reactor as a heating iiuid,
water or steam could be used as the cooling me
catalyst therein, smaller sizes down to about 100
dium, or the feed stock, steam, or auxiliary gas
mesh may be employed.
employed could be preheated by using it as the
Y The reaction is preferably carried out in the
cooling medium.
vapor phase, as indicated, although liquid phase
Although the process of this invention has been
operation may also be employed, such as by in 55
' described primarily as a hydrocarbon conversion
troducing a liquid feed through line I4, allowing
process, it may also be employed for shale oil
it to flow down through the catalyst bed in re
actor Il), and withdrawing the product through
eduction, oxidation, and like processes. For oxi- '
dation, oxygen may be substituted for at least a
This would necessitate maintenance of a
liquid level at or just above line I2, and provision 60 part of the auxiliary gas in the above systems.
For shale oil eduction, fresh granulated shale is
of means such as a trap for preventing loss of
added through line 21. In hopper 8 it is diluted
liquid product through line 3U.
'
with a controlled amount of hot recycled spent
The temperatures employed for cracking are
shale from line Sand separator 6, and passes into
generally high, in the range of about 800° F. to
2000° F. Many of the reforming operations such 65 reactor I0 used as an eduction chamber. In re
actor I0 itis heated, as by ñue gases in tube 26,
as dehydrogenation and aromatization also re
and subjected to stripping gas such as steam en
quire high temperatures in this range, but isomer
tering through line I2, the product leaving line
ization and hydrogenation for example may be
I4. The stripping gas may also enter line I4, and
carried on at lower temperatures, down to about
atmospheric. The pressures involved may range 70 the product leave through line I2 if desired to
provide for simpler recovery of liquid products.
from about atmospheric up to 100 atmospheres or
The educted shale, which generally contains »some
more, although for vapor phase operation pres
carbonaceous residue even though educted at tem
sures below about 20 atmospheres are preferable'.
peratures of 900? F. to 1500° F. is burned in cham
Operation of both the reaction and regeneration
processes at substantially the same pressure is 75 ber I6, the heat being absorbed by the stripping
line I2.
214085306
8
gas which enters through line I1, leaving line I8,
'and entering chamber I0 through line l2 or I4 as
described. Part of this preheated stripping gas
said reaction zone, regenerating said catalyst in
said regeneration zone, withdrawing regenerated
catalyst from said regeneration zone, suspending
may also- be charged into line l to carry the de
the withdrawn catalyst in a suspension gas com
steam generation or the like.
said reaction zone, adding to said separated sus
sired amount of recycled spent shale through line 5 prising hydrocarbon feed to thereby lift said cata
lyst and pass it to a separating zone, separating
5, or flue gases from line 26 may be used. The
said catalyst from said 'suspension gas in said
spent shale not recycled is Iwithdrawn through
separating zone, passing the separated catalyst to
line 28. Its heat content may be employed for
The stripping gas
may also be flue gas, nitrogen and the like al
though hydrogen and light hydrocarbons from
the product leaving chamber l0 are preferred.
Other modifications of the processes of this in
vention which would occur to one skilled in the
art are to be considered within the scope of this
invention as defined in the following claims:
‘
I
claim:
'
.
' 1. A process for the catalytic conversion of hy
'drocarbons which comprises ilowing a granulated
catalyst downwardly by gravity through succes
sive zones of reaction and regeneration, introduc
ing hydrocarbons into said reaction Zone and
maintaining an elevated conversion temperature
-therein while said hydrocarbons flow through said
reaction zone countercurrently to said flowing
catalyst, regenerating said catalyst in said re
generation zone, withdrawing regenerated cata
pension gas ñue gases having a temperature be
tween about 2000° F.> and 4000" F. so as to give
a preliminary thermal cracking `to said hydro
carbon feed at a temperature between about 1000°
F. and 2000° F., and passing the resulting gaseous
mixture through said reaction zone countercur
rently to said flowing catalyst.
6. A process according to claim 5 in which the
catalyst granules are between about 4 and 20
mesh in size.
7. An apparatus for the catalytic conversion of
hydrocarbons _which comprises a reactor and a
regeneration chamber so connected and arranged
that granulated catalyst may ilow by gravity suc
cessively through said reactor and regeneration
chamber, means for introducing catalyst into said
reactor, means for introducing a gaseous mixture
into said reactor to pass countercurrently to said
catalyst, means for maintaining an elevated tern
perature in said reactor, means for regenerating
withdrawn catalyst in a suspension gas to thereby
said catalyst in said regeneration chamber, means
lift said catalyst and pass it to a separating zone, 30 located near the bottom of said regeneration
separating said catalyst from said suspension gas
chamber for controlling the rate of flow of cata
lyst from said regeneration Zone, suspending said
in said separating zone, passing said separated
catalyst to said reaction zone, and introducing
said separated suspension gas into said reaction
_zone with said hydrocarbons.
2. A process according to claim 1 in which the
suspension gas comprises hydrocarbon feed,
` p V3. A process according to claim l in which the
suspension gas comprises hydrogen.
lystrthrough‘said reactor and said regeneration
chamber, outlet means for removing said catalyst
from said regeneration chamber, separating
means positioned above said reactor for separat
ing gases from catalyst, means connecting said
outlet' means ‘with said separating means, means
for introducing a suspension gas into said con
4. A process according to claim 1 in which the 40 ‘nesting’ means to thereby suspend said catalyst in
suspension gas comprises light hydrocarbon gases.
5. A process for the catalytic conversion of hy
drocarbons which comprises flowing granulated
catalyst downwardly by gravity through succes
sive Zones of'reaction and regeneration, main 45
taining an elevated conversion temperature in
said suspensiongas and lift said catalyst into said
separating means, and means for introducing sus
pension gases separated in said separating means
into said reactor together with said gaseous
mixture.
"
_
CLYDE H. o. BERG.
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