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Патент USA US2406547

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Aug. 27, 1946.
P_ E, KUHL 5|- AL
2,406,547
CATALYTIC CRACKING PROCESS
Filed Sept. 7, 1940
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2,406,547
Patented Aug. 27, 1946
UNITED STATES PATENT OFFICE
2,406,547
CATALYTIC CRACKING PROCESS
Paul E. Kuhl, Madison, and Albert B. Welty, Jr.,
Roselle, N. J., assignors to Standard Oil De
velopment Company, a corporation of Delaware
Application September 7, 1940, Serial No. 355,740
2 Claims. (Cl. 196—52)
1
This invention relates to an improved process
for the catalytic cracking of hydrocarbons and
has particular reference to methods for prepar
ing two or more improved products from a single
feed stock.
In the catalytic cracking of hydrocarbons, the
process may be carried out in such a, manner that
both the materials undergoing cracking and the
catalyst are passed continuously through the
cracking zone. With this type of operation the
composition of the cracked products remains sub
2
of a gas oil fraction of the cracked products
which is especially suitable for further catalytic
cracking and which may be used as a cycle stock
in the process.
Another object of the present invention is to
provide an improved process for the catalytic
cracking of hydrocarbons in which there are pro
duced low boiling and gaseous products which are
particularly adapted for treatment in other proc
10 esses involving recovery of hydrocarbons from the
cracked gases or the use of the cracked gases for
gas reversion, polymerization, the production of
stantially uniform for any ?xed set of reaction
specialty products such as alcohols and the like.
conditions.
Other and further objects of this invention
Another method of catalytic cracking is con
ducted. by passing hydrocarbons through a re 15 will be apparent from the following description
and the drawing.
action zone having a cracking catalyst main
The drawing is a diagrammatic illustration in
tained therein and periodically stopping the ?ow
partial sectional elevation of an apparatus suit—
of hydrocarbons and regenerating the catalyst
able for carrying out a process involving one
by passing suitable oxidizing gases through the
reaction zone. The operation thus comprises a 20 modi?cation of the present invention and illus
trates the ?ow of materials.
series of cycles of alternate cracking of hydrocar
Turning to the drawing, a suitable hydrocar
hens and regeneration of the catalyst. It has
bon stock for catalytic cracking, such as a pc
now been found that the nature of the cracked
troleum gas oil, is supplied in line I and is passed
products changes materially during the cracking
by pump 2 through a vaporizing coil 3 to an inlet
cycle in such a “run-blow" operation and that it
manifold ll. Vapors pass from this manifold
is advantageous to segregate these products in
through line 5 into a vessel 6 which contains a
accordance with their individual ?tness for the
packing or ?lling of a suitable cracking catalyst
production of different ?nished products such as
1, such as an active or activated clay or a syn
aviation gasoline, Diesel oil, etc, and for further
30 thetic gel type catalyst containing oxides of
utilization in other processes.
silica, alumina, magnesia or various combinations
One object of this invention is to provide a
of such oxides. The catalyst 1 may be disposed
process for the catalytic cracking of hydrocar
in the vessel 6 in any suitable manner, such as
bons by which cracked products of widely dif
by being packed in this vessel or being placed
ferent characteristics may be prepared.
Another object of this invention is to provide . therein on trays, in baskets and the like. Or the
catalyst particles may be partially or even sub
a catalytic cracking process which is especially
stantially completely suspended in a rising stream
adapted for ‘the preparation of improved avia
of gas or vaporous reagents, being thus main
tion gasoline.
tained in the reaction vessel, in a state of limited
Another object of this invention is to provide
or vibratory motion. It is desirable that substan
a catalytic cracking process which is especially
tially all of the catalyst remain in the reaction
adapted for the preparation of products of high
vessel and that any carried out of the reaction
aromatic hydrocarbon content.
vessel with the gaseous products be separated
Another object of this invention is to provide
therefrom and returned to the reaction vessel or
an improved process for the catalytic cracking of
that a relatively stationary mass of catalyst be
hydrocarbons by which motor gasoline may be
used to treat the ?owing stream of hydrocarbons.
produced with a minimum of re?ning treatment.
_ The cracked hydrocarbons leave the vessel 6
Another object of this invention is to provide
by line 8 and are passed through line 9, condenser
an improved process for the catalytic cracking of
ill and line I! into a separating vessel l2. Un
hydrocarbon oils which is adapted to produce an
condensed gaseous products are withdrawn by
improved Diesel fuel having a high Diesel index, .
line i3, liquid products by line H and any water
and which is also especially suitable for the pro
present in the cracked products (such as that
duction of high quality kerosene.
resulting from the use of steam in the vaporiza
Still another object of the present invention
tion and/or cracking zones) by line IS.
is to provide an improved catalytic cracking
The cracked products leaving the condenser l0
process which is characterized by the production 55
3
2,406,547
4
may also be passed by line IE to a second sepa
high to remove carbonaceous material from the
rating vessel I‘! provided with a line l8 for taking
catalyst, but should not be permitted to rise at
off uncondensed gases, line 19 for oils and line 20
any time high enough to injure the activity of
for water.
the catalyst. The regeneration temperature is
Means are also provided for regenerating the 5 preferably maintained between about 800 and
catalyst by treatment with air or other suitable
1100°, and temperatures exceeding 1200° will gen
oxidizing gases. These comprise a gas supply
erally be found harmful to the activity of the
line 2| from which an oxidizing gas is passed by
‘silica-alumina type of cracking catalysts.
blower 22 through manifold 23 and line 24 into
The operation of the apparatus illustrated in
vessel 8. The regenerating gases leave the vessel 10 the drawing will now be described in connection
6 by line 25 and may be vented through line 26 '
or a part thereof may be recycled by line 21 to
the blower 22.
with an example illustrating a suitable manner
for conducting the process of this invention.
EXAMPLE 1
One or more alternate catalytic cracking ves
sels, such as the vessel 28, may be used in parallel 15 A petroleum gas oil distillate fraction boiling
connections with the vessel 6 so that one vessel
between about 500 and 700° F. and having a
may be used for cracking hydrocarbons while
density of 33“ A. P. I. and an aniline point of
the catalyst in the other vessel is undergoing re
174° F. is supplied as the feed stock and is heated
generation. For example, the vessel 28 is pro
rapidly in the vaporizer 3 to a temperatue of about
vided with a hydrocarbon vapor supply line 29
910° F‘. as rapidly as poss‘ble in order to avoid
and cracked products withdrawal line 30, a re
the formation of coke. Any unvaporized mate
generating gas supply line 3| and a regenerating
rial may be separated from the products leaving
gas drawoil‘ line 32.
the vaporizer 3 and the vapors are then passed
The cracked products collected in vessels l2
through manifold 4 and line 5 into vessel 6 which
and I 1' may be subjected to any suitable rectifica 25 conta‘ns a fresh or freshly regenerated cracking
tion and re?ning treatments to prepare aviation
catalyst at a temperature of aboue 850° F. Hy
gasolines, motor gasolines, kerosene, burning oil
drocarbon vapors are passed through the crack
distillates, Diesel oils, fuel oils and the like as
ing vessel 6 at a rate of about 0.3 volume of hy
may be desired. For example, the liquid con~
drocarbon (liquid base) per volume of the cata
densate received in vessel I‘! may be passed by 30 lytic cracking zone per hour. The cracked
line I! through heating coil 33 into a distillation
products are withdrawn from vessel 6 through
column 34 which may be operated to separate
lines 8 and 9 and are passed through condenser
cuts or distillate fractions of any desired vola
l0 into the separating vessel l2 by line I I. After
tility. For example, a column may be operated
the cracking vessel has been in use for a time
so as to take off the overhead distillate through 35 the activity of the cracking catalyst undergoes
line 35, a heavy naphtha fraction through line
36 from the trapout tray 31, a gas oil by line 38
from the trapout tray 39 and a residue by line 40.
a change which is evidenced by changing char
acteristics in the cracked products. The sepa
rating
vessel 12 is then shut off and the cracked
The gas oil may be used as cycle oil in the process
products are passed from the condenser I0
and may be recycled by pump M and line 42. It 40
through line I6 into vessel I1. After further use
may also be withdrawn by line 43 for treatment
the activity of the cracking catalyst decreases to
by any other suitable process, such as cracking,
the extent that further operation is undesirable
catalytic cracking or destructive hydrogenation.
and the supply of hydrocarbon vapors is shut oil’
The condensate collected in vessel l2 may also
in line 5 and is diverted through the manifold 4
be fractionated in the tower 34 or in a separate
and line 29 to vessel 28 which at this time con
tower. it being preferred to keep the condensates 45 tains
a fresh or freshly activated cracking cata
in vessels I2 and I1 separate in the distillation
lyst
and
which may be operated under the same
and refining treatment until substantially ready
conditions just described for cracking vessel 5.
for blending into ?nished products.
The cracked hydrocarbon products leave the
The catalytic cracking operations of this in
vessel 28 by line 30 and, during the initial stages
vention are preferably conducted at elevated tem 50 of
the cracking cycle, are passed through line 9,
peratures, such as for example, from 600 to 1200°
condenser I0 and line H into vessel I2. During
F., preferably between about 650 and 1000“ F.,
the latter stages of the cracking cycle these
and with the hydrocarbons substantially com
cracked products are diverted through line I6
pletely in the vapor phase. The time of treat
ment should be adjusted in regard to the crack 55 into vessel l1, the vessels i2 and I‘! thus serving
to receive cracked products from the initial and
ing temperature, catalyst activity and other fac
?nal portions, respectively, of the cracking cycle
tors, so as to secure a conversion of about 25 to
from each of the cracking vessels.
65% of hydrocarbons boiling below 400° F. from
While the vessel 28 is being used on the crack
the heavier hydrocarbons passed through the
60
ing
cycle, the catalyst in vessel 6 may be under
cracking zone. The feed rate will ordinarily be
going regeneration. This is accomplished by
between the limits of about 0.1 and 20 volumes of
forcing an oxidizing gas such as air, which is
oil (liquid basis) per volume of cracking zone per
preferably
diluted with steam, nitrogen, ?ue gas
hour and the operation is preferably conducted
or the like, in order to avoid too rapid oxidation
with a feed rate below about 5.0. The length of
the cracking cycle will also depend largely on 65 of the catalyst, by means of a blower 22 through
the manifold 23 and line 24 into the vessel 6.
the activity of the catalyst and may range from
The regenerating gas is preferably supplied in
10 minutes to about 12 hours, and cycles of longer
manifold 23 at a temperature of about 700-800u
than about 20 minutes each are generally pre
F. and at such a rate and oxygen content that
ferred.
70 the temperature of the catalyst 1 does not rise
Following the cracking cycle, the catalyst is
above about 1100“ F. at any time during the re
regenerated by treatment with suitable oxygen
containing gases, such as air, air diluted with ni
trogen or steam, ?ue gas and the like. The tem
generation. When the catalyst is substantially
regenerated, as indicated by a dropping off in the
oxides of carbon in the used regenerating gases
perature of regeneration should be sufficiently 75 leaving vessel 6 by line 25 and by decreasing
2,406,547
catalyst temperatures, the vessel 6 is ready for
use again in cracking hydrocarbons. The re
generating gas may then be cut oil‘, the catalyst
purged with steam or inert gas to remove oxy
C4 hydrocarbons were produced during an 811
tire four hour cracking cycle, while in the ?rst
thirty minutes of this cycle 4.5% by weight of
dry gas and 7.5% by weight of C4 hydrocarbons
were produced. 01’ the C1 hydrocarbons pro
duced during the ?rst thirty minutes, 32% were
gen, and hydrocarbon vapors may be again sup
plied by line 5, thus starting a fresh cracking
cycle for this vessel. The cracked products ob
tained in the initial stages of this cycle are passed
unsaturated, while 41% of the 64 hydrocarbons
produced during the entire four hour cycle were
unsaturated. Thus it is desirable to segregate
to vessel l2 and those from the latter stages of
the cycle to vessel H as before. The catalyst 10 the gas produced during the di?erent stages of
the cracking cycle in accordance with its in
in vessel 28 may similarly be regenerated during
tended use. The gas from the initial stages of
the carrying out of the cracking cycle in vessel 6.
the cracking cycle is advantageously segregated
It will be understood that the process may be
for use in gas reversion-catalytic cracking proc
conducted with any additional number of reac
esses or where the recovery of the entire 04 cut
15
tion vessels as may be desired and that these
is desired, while the gases from the latter por
can be used in parallel with vessels 6 and/or 28
tion of the cycle may be used for the production
or in any intermediate stages between these
of a C4 out which is intended for polymerization
vessels in the cracking and regenerating cycles.
or for the production of specialty products such
Provision should be made for segregating the
products obtained in the initial and ?nal stages 20 as alcohols.
EXAMPLE 2
of the cracking cycle from all such vessels, which
may be done by connecting their cracked prod
There is presented in the following table an
ucts outlet lines to vessels l2 and I1.
outline of the operating conditions used and of
It will also be understood that provision may
be made for segregating the products obtained 25 the results obtained in catalytic cracking of an
East Texas petroleum gas oil distillate fraction of
in any desired number of portions of the crack
33.3° A. P. I. over an activated clay cracking cata
ing cycle, for example, other receiving vessels
lyst at a feed rate of 0.3 vol. of oil per volume of
may be connected to receive cracked products
catalyst per hour. The products from six consec
in parallel with vessels 1! and I1, and the prod
ucts of any intermediate portion of the cracking 30 utive periods of six cracking cycles were separately
collected and composited for each period, each
cycle may be separately collected in any of such
composite product then being distilled for maxi
vessels.
mum workings of aviation gasoline, heavy naph
In carrying out the process of this invention
tha and l2# Reid vapor pressure, 400° F. end point
as described in the above example, it has been
noted that the products obtained in the initial 85 gasoline.
Segregation of Products from Portions of the Cracking Cycle
Parti'oi cracking cycle
1
Length, hrs ___________________________________________________________ __
2
3
4
5
0-0. 25
0. 26-0. 50
0. 50-1. 00
1. 00-2. 00
1. 00.3. 00
904
907
6
B. 004. 00
Operating conditions:
Temperatures, ° F.—
Reactor inlet _________________________________________________
_.
_
Reactor outlet _________________________________________________ __
Yields on oil led:
l2# R. V. P.—400° F. E. P. gasoline, per cent vol ________ __
910
911
B61
883
873
851
877
874
842
853
860
849
836
832
872
844
867
846
852
847
839
822
50. 5
46. 6
41.1
29. 1
Aviation gasoline, per cent vol
29. 8
25. 9
23.0
16.4
Heavy naphtha, per cent vol ____________________________ ._
l4. 2
14. 7
13. 0
9. 5
24
29
37
60
111
117
115
104
Aviation gasoline inspections:
d best, °
_____________________________________________________ .-
Aniline point, ° F ___________________________________________ __
__
Heavy naphtha inspections:
Acid heat, “
____ _.
Aniline point, ° F._
l2# R. V. P.—-400° F. E
ll
l0
12
19
30
54
59
73
28
33
40
57
ll
10
10
inc inspections
Acid heat, °F ____________________________________________________ .-
Bottoms or cycle stock inspections:
Acid heat, ° F ___________ --
Aniline point, ° F
Gravity, " A P
_____ __
7
126
135
145
158
25. l
28. 2
30.4
32. 4
‘Z7. 2
7. 2
34. 6
8- 9
41. 2
10.9
48. 3
16. 8
04 cut inspections:
Total unsaturates, per cent ________________________________________ _.
Isobutylene, per cent ______________________________________________ __
It will be seen from the above table that the
stages of the cracking cycle are quite different
distillate fractions of the cracked products boil
from those obtained in the latter stages and
that very great advantages may be secured by ” ing in the motor fuel range are characterized by
an increase in the unsaturate content and a de
segregating these products. For example, more
crease in the aromatic content as the cycle pro
hydrocarbons of 4 carbon atoms per molecule
gresses. It is desirable to segregate the distillate
are formed at the beginning of the cycle than
from the ?rst part of each cracking cycle for the
at the end, while those produced at the end of
the cycle contain the greater proportion of un 70 production of aviation gasoline. Finished avia
saturates. For example, operating under con
ditions similar to those described in the above
example, 3.5% by weight (based on the feed to
the cracking zone) of dry gas (free of C4 and
tion gasoline should have a low acid heat repre
senting a low content of ole?nic hydrocarbons.
The aviation gasoline produced in catalytic crack
ing operations usually has an excess of such un»
heavier hydrocarbons) and 2.7% by weight of 75 saturates, and in ?nishing the gasoline to aviation
7
2,406,547
speci?cations, these unsaturates must be removed.
Re?ning losses are decreased and the re?ning
process simpli?ed by selecting the distillate frac
tions of the ?rst portions of each cracking cycle
tained in the latter stages of the cracking cycle
are particularly suited for the production of
kerosene. Aromatic and unsaturated hydrocar
?fteen minutes of the cracking cycle was 24° F
fractions of the cracked product of the latter
stages of the cracking cycle and to subject this
to suitable re?ning treatments for the production
of water white kerosene.
The heavy fractions of the cracked products
bons are both undesirable in kerosene used for
for the production of aviation gasoline. In an to lighting purposes. The unsaturates may be read
illustrative process conducted as described in the
ily removed by treating, but the removal of arc
above example, the acid heat of the aviation gas
matic compounds is much more dif?cult. Thus
oline distillate fraction produced during the ?rst
it is preferred to segregate the kerosene distillate
while the acid heat of the aviation gasoline pro- "
duced during the third hour of the cracking cycle
was 60° F.
The aromatic content of the distillate fraction
of the cracked products is also greatest at the
beginning of the cracking cycle and the segrega v15 not used to produce Diesel oils, fuel oils or kero
sene as described above may be subjected to fur
tion of this ?rst distillate for the production of
ther cracking or other destructive treatments to
aromatic solvents and of even more highly con
produce motor fuels. The entire heavy fractions
centrated aromatic hydrocarbons is also advan
may be used as cycle stock in the process of this
tageous. For example, the heavy naphtha dis
invention. However, it is preferable to segregate
the heavy fractions produced during the latter
tillate fraction boiling ‘between about 300 and
400° F. of the products obtained during the ?rst
?fteen minutes of the cracking cycle under op
erations similar to those described in the‘ above
example had an aniline point of 30° F. and an
portion of the cracking cycle and to use it as
cycle stock in this process, as this portion of the
heavy fractions has a higher aniline point and
higher gravity than that produced during the
?rst part of the cracking cycle and is better
acid head of 11° F., while the heavy naphtha dis- ,
tillate fraction produced during the third hour
of the cracking cycle had an aniline point of 73°
tha fraction of the products of the early portion
of the cracking cycle with liquid sulfur dioxide,
phenol or other selective solvents, to concentrate
the aromatic hydrocarbons therein.
The segregation of the motor fuel distillate
adapted to cracking for maximum yield of gaso
line. The heavy fractions obtained in the early
stages of the cracking cycle are relatively more
aromatic in character and are less suitable for
catalytic or non-catalytic cracking. These frac
tions, however, may be subjected to destructive
hydrogenation under conditions suitable for the
production of gasolinesv high in aromatic con
tent, and form a desirable feed stock for such
fractions produced during the various stages of
the cracking cycle is also advantageous in that
the degradation of the gasoline and the treat—
This invention is not to be limited by any
speci?c examples or explanations presented
F. and an acid heat of 19° F. Aromatic solvents
of high purity are thus prepared by any suit
able treatment, such as by extraction of the naph- , 30
treatment.
herein, as all such are intended solely for pur
pose of illustration. It is the applicants’ inten
' _tion to claim their invention as broadly as the
ing costs are decreased. In the ?nishing of the
motor fuel distillates to motor gasoline speci?ca
tions, the motor fuel distillate fractions pro
duced in the early stages of the cracking cycle
prior art permits.
We claim:
are quite stable and in many cases will be' found
to be suitable for use directly as gasoline or after
a. very slight re?ning treatment to remove any
-
- ~
7
l. A hydrocarbon oil conversion process which
comprises providing a bed of fresh cracking cat
alyst and maintaining said bed at catalytic con
version temperature during a period of process
mercaptans present. The motor fuel distillate
fraction produced during the mid portion of the
cracking cycle is somewhat less stable and usually
requires a mild re?ning treatment, while the
ing, continuously passing a stream of hydrocar
bons through the catalyst bed during the process
motor fuel distillate fractions produced in the
last part of the cracking cycle are relatively un
ing period and converting a substantial portion
of the hydrocarbons into gasoline in said bed,
stable and require more severe re?ning treatment.
said stream being introduced to said bed at a
Also, the gasoline produced in the early part
of the cycle usually is sweet, but, especially with
substantially uniform conversion temperature
throughout the processing period, whereby the
activity of the catalyst is gradually diminished
by deposition of carbonaceous matter thereon,
high sulfur feed stocks, there is a tendency for
the gasoline produced during the latter stages of 55
the cycle to become slightly sour. In this case,
producing from the hydrocarbons a substantial
the ?rst gasoline produced may by-pass the
ly saturated gasoline during the initial portion
sweetening treatment and thus save considerable
of the processing period when the catalyst bed
handling expense.
is in a state of high activity and an unsaturated
The heavier fractions of the cracked products 60 gasoline during a subsequent portion of said
boiling above the motor fuel range are charac
period when the catalyst bed is in a state of
diminished activity, and separately collecting said
substantially saturated gasoline and said unsat
terized by a decrease in the content of aromatic
hydrocarbons and an increase in the unsaturate;
content as the cracking cycle proceeds. The*' ‘
gravity and aniline point of these heavy frac—
tions produced during the last part of the crack
ing cycle are higher than those of the heavy
fractions produced during the ?rst part of the
_
urated gasoline.
2. A hydrocarbon oil conversion process which
comprises providing a bed of fresh cracking cat
alyst and maintaining said bed at catalytic con
‘version temperature during a period of process‘
cycle; the Diesel index is therefore greatest for.‘ _ ing, continuously passing a stream of hydrocar
the heavy fractions of the cracked product pro
bons through the catalyst bed during the process
duced in the latter stages of the cracking cycle.
ing period and converting a substantial portion
The segregation of these heavy fractions for the
‘of the hydrocarbons into gasoline in said bed,
production of Diesel fuels is thus advantageous.
‘said stream being introduced to said bed at a
Similarly, the fractions boiling in the kerosenei
substantially uniform conversion temperature
or burning oil range of the cracked products 010- ‘3 throughout the processing period, whereby the
at
2,406,547
activity of the catalyst is gradually diminished
by deposition of carbonaceous matter thereon,
producing from the hydrocarbons a substantially
saturated gasoline during the initial portion of
the processing period before there has been de
posited on the catalyst bed a su?icient quantity
of carbonaceous matter to materially impair the
catalytic activity of the bed, condensing and col
lecting the saturated gasoline thus formed, pro
10
ducing from the hydrocarbons an unsaturated
gasoline during a subsequent portion of the proc
essing period when the catalyst bed has received
a sufficient deposit of carbonaceous matter to
substantially reduce its catalytic activity, and
condensing and collecting said unsaturated gas
oline independently of said saturated gasoline.
PAUL E. KUHL.
ALBERT B. WELTY, JR.
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