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Патент USA US2121026

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June 2l, 1938.
Filed May 5, 1932
:05. Mm‘ZOn
Patented June 21, 1938 `
Pnocnss Fon REFINIITS; AND coNvEn'rINc
Chauncey B. Forward, Urbana, Ohio, assignor,
by mesne assignments, to Forward Process
Company, Dover, Del., a corporation of Dela
Application May 5, 1932, Serial No. 609,405
5 Claims. (Cl. 196-61)
'I'he present invention relates to the cracking
of hydrocarbon oils in the vapor phase. More
particularly the invention relates to an improved
process for converting crude petroleum or high
boiling point distillates thereof into synthetic
gasoline or other low-boiling point distillates.
The present process is a continuation in part
of the inventions disclosed in my copending ap
plications for patent, Serial No. 682,477, ñled De
10 cember 24, 1923, and. Serial No. 330,490, ñled
October 13, 1919, now Patent No. 1,903,810
granted April 18th, 1933.
Prior application Serial No. 330,490 filed in
1919 discloses a process for cracking petroleum
15 oils containing heavy residues in which the oil
was passed through coil sections mounted in pre
heaters and heated to a temperature suflicient to
vaporize a substantial proportion of the oil. The
resulting vapors and unvaporized oil constituents
20 Were then discharged into a vapor liquid sepa
rator in which the heavy residual constituents
were separated from vapors.
The vapors were
then passed at high pressure through a plurality
of coil sections and heated to a high cracking
25 temperature to convert the oil constituents into
a very high percentage of gasoline or motor fuel
out in the carbon settling column and the re
maining vapors conducted to the heat exchanger
for preheating the oil stock to be cracked. The
vapors were fractionated to recover a gasoline
produced in the cracking operation. A pressure
of from 200 to 500 poundsvper square inch was
maintained in the enlarged carbon settling col
'I'he primary object of the present invention is
to provide a method of converting high boiling 10
oil to lower boiling products in a manner yield
ing a high percentage of high quality product
Without production of substantial amounts of
low grade liquid and solid residue.
To accomplish this object, the principal fea 15
ture of the invention contemplates the treat
ment of the crude petroleum or other high-boil
ing oil and vapors thereof, in a continuously and
rapidly flowing stream of relatively small cross
section, to the successive steps of:r preheating; 20
vaporization under pressure; separation of any
unvaporized liquid; exposure of the iiowing va
por stream under high pressure to cracking tem
peratures for a period lof time suiiicient to effect
substantial cracking while passing the vapor 25
stream through the cracking zone at a velocity
content and a relatively small proportion 01E at which formation and deposition of coke or
free carbon. The stream of vapors from the sludge in the cracking zone is prevented. Any
cracking coils was passed at high velocity into an ' free carbon formed is deposited at the discharge
30 enlarged chamber in which the free carbon was end of the cracking zone in a dry, flulfy form;
separated from the vapors.
The vapors from separation of such carbon from the cracked gas
the carbon separating chamber Wereconducted
to a condensing system in which the desired gas
oline product was recovered.
Prior application Serial No. 682,477 discloses
a process for cracking hydrocarbon oils, partic
ularly distillates, which are completely Vaporiz
able, by passing the distillate through a vapor
heat exchanger in heat exchange with high tem
40 perature vapors produced in the cracking oper
ation. The preheated oil was then conducted
through a plurality of heating coils and brought
to a temperature of approximately 850° F. after
which it was passed through a further series of
45 coils Where cracking was effected at temperatures
of approximately 975° F. The oil vapors passing
through the cracking coils were converted into
a substantial proportion of gasoline and a rel
atively small proportion of free carbon.
50 resulting mixture was conducted from the crack
ing coil into an enlarged carbon settling column
Where a temperature of from 850° to 900° F. was
maintained solely by the heat of the vapors in
troduced into the column in which some further
55 cracking occurs. The free carbon was settled
oline vapors being accomplished by simple grav
ity settling in a carbon collecting chamber
through whichl the cracked vapors pass at re
tarded velocity before entering the first element 35
of the cooling and condensing train. Other ob
jects and features of the invention will be appar
ent from the following description.
In the accompanying drawing I have shown in
diagram apparatus adapted for the practice of 40
the process of the present invention.
As illustrated in the accompanying drawing,
the crude petroleum or high boiling oil distil
late to be treated is forced under high pressure
by'a pump I0 through preheating coils I2 with 45
in a hot vapor heat exchanger I4. After passing
through the heat exchanger land therein becom
ing preheated to a temperature of about 300°
400" F., the oil passes under‘pressure through
a pipe I6 into the iirst of a connected series of 50
coils I8 of pipe of small diameter and great
length. The first pipe coil I8 is mounted in the
first member 20 of a connected series of heat
ing, vaporizing and cracking chambers 20, 22, 24,
26, 28, 30, 32, 34, 36 and V38. After flowing 55
through coils I8 in chamber 20 the oil continues
its flow successively and uninterruptedly through
similar coils I8 mounted in each of the cham
bers 22, 24, 26, 28 and 30. In passing succes
sively through the coils of heat exchanger I4
and the ñrst few heating chambers 20 to 30,
the oil is gradually heated to a temperature of
Vapor heat exchanger I4, where they are cooled
by direct heat exchange with the crude forced
through the coils thereof by pump I0. High
boiling point oils are separated from the cracked
vapors by condensing in exchanger I4, and the
lower boiling point cracked gasoline vapors pass
out of the exchanger through a valved pipe 54
about 850° F., so that all of the gasoline and
and are conducted through the coils of a con
higher boiling point components of the oil are . denser 56 and thence through a train of con
10 vaporized, leaving only a small amount of the
heaviest ends of the oil in an unvaporized liquid
state. After passing through the coils I8 of
chambers 20 to 30, the mixture of oil and vapors
is discharged, still under high pressure and tem
perature, into a separatoi` 40. Due to the de
crease in velocity of flow of the oil and vapor
mixture through the enlargedv cross section of
the separator 40, gravity separation of the un
vaporized liquid residue from the major vapor
20 ized fraction of the oil takes place therein prior
to the subjection of the vapors to substantial
Anyliquid residue collected at the bottom of
separator 40 is continuously discharged through
25 valved pipe 42 and conducted to a cooler 44, and
thence to a storage tank 46. The oil vapors are
conducted from the top of separator 40 by a
continuation of coiled tubing I8 in a rapidly
flowing stream successively through the coils of
densing and reiining apparatus (not shown).
The oil vapors in separator 40 are maintained
under high pressure and at a temperature up to
800° F. to 850° F. The cracked oil vapors enter
ing the carbon settling column 50 are maintained
preferably under pressures of 400 to 500 pounds 15
or higher and temperatures of 960° F. to 980° F.
The temperature of the vapors drops during
their sojourn in chamber 50 to about 850° F.
to 900° F.
The dry, fluiîy carbon which `collects in pre 20
cipitator 50 gradually accumulates and may be
periodically removed through a relatively large
valved pipe 58 to a second sealing chamber 60.
From chamber 60 the carbon may be removed
while the plant is operating without danger of 25
lire, through a manhole 62, during periods when
communication between chamber 00 and pre
cipitator 50 is cut off by closingr valved con
nection 58.
All of the heating chambers, heat
30 the vapor phase cracking zone of the apparatus
exchangers, separators, and pipes conveying and 30
in heating chambers 32, 34, 3S and 38. In this
holding the steam, hot oil and vapors are thor
oughly insulated against heat losses with as
bestos or other suitable heat insulating material.
Heating of the crude oil and vapors passing
successively through the tube coils I8 of cham 35
bers 20 to 38 may be effected by indirect heat
exchange with superheated steam or hot fur
cracking zone the vapors are further heated
under high pressure, (i. e., 200 to 500 pounds
per square inch or more) to temperatures of
35 950 to 1000° F. Y
The cracked vapors issuing from the last
chamber 38 of the cracking zone are conducted
by a continuation of tubing I8, still under high
pressure and temperature, through a valved in
40 let 48 into a carbon settling chamber 50. In
chamber 50 the velocity of flow of the cracked
oil vapors is reduced to a point where gravity
separation takes place of the cracked vapors
and any carbon formed in the cracking Zone.
45 The drop in velocity flow of the vapor stream re
sults from the relatively large cross section of
the chamber 50 as compared to the small cross
section of the coils I8 of the vaporizing and
cracking elements. The relatively small amount
50 of carbon formed as a decomposition product of
nace gases passed successively in reverse direc
tion to the flow of crude and vapors, through
chambers 38 to 20 inclusive. When superheated 40
steam is used as a heating medium, it is prefer
ably generated in coils 64 of a flash boiler 66
to which feed water is continuously fed by a
high pressure feed pump 68. Superheated steam
at a temperature of 1150° F. to 1200° F. or higher 45
and under a pressure above 250 pounds, is con
ducted from the boiler directly to manifolds 70,
thence through the chambers 32--38 forming
the cracking zone of the apparatus. After pass
ing through chambers 32-38 the steam is con
the cracking operations in accordance with the
present process is notable for having uniformly
ducted successively through the chambers 30--20
forming the preheating and vaporizing zone,
dry and finely powdered íiuiîy characteristics,
from the ñrst element 20 of which the steam
ñnally exhausts at a pressure of 100-200 pounds
resembling carbon black.
The process contemplates high Velocity of flow
of the oil vapors through the cracking tubes of
per square inch into a drum 'I2 having a valved 55
offtake ‘54. The temperature of the steam in
the apparatus,--i. e~ through the coils I8 of chamber 30 is maintained at about 850° F. to
chambers 32 to 38 inclusive, and a prolonged 900° F., and the temperature of the steam in
time of exposure of the vapors to cracking tem
drum 'I2 is normally maintained at about 400°
60 peratures in the chambers 32 to 38 and in the
F., or in other words at a temperature at which 60
settling chamber 50, so that no deposition of it is still suitable for use in industrial heating
coke or sludge takes place at any point in the' and for power purposes.
cracking tubes. The above-noted character
Valves are mounted at suitable points in the
istics of the carbon residue of the cracking op
pipe connections wherewith to regulate and
65 eration of the present process result apparently
maintain the proper Working pressures in the 05
:from the controlled differential conditions of oil preheating, vaporizing and cracking Zones.
rapid turbulent flow of vapors and prolonged Likewise valved pipe connections are provided
time of exposure of vapors to cracking tempera
between the boiler or equivalent source of heat
tures and pressures in apparatus of the type, and ing fluid and the separators whereby to permit
with the small dimensioned cracking tubes of preliminary heating of these apparatus elements 70
great length, illustrated in the accompanying
From the carbon precipitator 50 the cracked
vapors pass out at a temperature of about 850°
75 F. to 900° F. through valved pipe 5,2 into the
in starting operations. Valved pipe connection 'I6
between chamber 60 and condenser 56 serves to
release the small amount of vapors accumulat
ing under pressure in chamber 60 periodically as
a result of blowing carbon thereinto from the
2; 11e-1,0262'
. carbonsettiingxcolurnn; ‘Manhoie 1'4la1iords'in-
the‘liquidlstat‘ethrough an elongatedîzone 0f re-`
spection ofthe interior of .the carbon settling
stricted. cross sectionfat high velocity whereby
" A small amount of vapor phase crackingr may
` take place `in the coil- section I8À mounted in
vaporizing chamber 30, but the major portion
ofthe cracking takes place in the coils of the
cracking. zone `(chambers 32-38» inclusive) and
in' carbon settling column- 50".
The heavy oil taken off from the bottomy of>
heat exchanger IÍ4 throughvalved offtake '18, as
well as that taken oif from the bottom of sep
arator 40, carries substantially no free carbon
in solution and accordingly is in a condition
15 where it can be put through the process again,
either by itself or blended with some of the cru-de `
or distillate originally run.
all components are maintained in intimate ad
mixture and gradually superheating the vapors
thereinto a temperature in excess of 950 degrees
F., discharging the superheated vapors into an
enlarged zone' wherein the velocity -of said vapors
is reduced, maintaining the temperature of the
vapors in said enlarged zone above the cracking
temperature and controlling the time of exposure 10
ofv said vapors t'ol'the cracking treatment.` inthe
last mentioned elongated heating zone and in
said enlarged zone so as to permit the precipita
tion of only substantially dry carbon in said
enlarged zone.
3. 'I'he process of cracking mineral oils which
comprises passing the oil constituents to be
cracked while substantially all in vapor state
and at an initial temperature of about 800° to
850° F. in a confined stream and at high velocity 20
through a heating and cracking zone, heating
The lower 3 to 5 rows of pipe in the flash
boiler may be made of specially treated tubing
20 or calorized pipe which will withstand several
hundred degrees higher vtemperature than ordi
nary steel tubing without oxidizing. Since no
direct heating of the oil pipes by ñre or llame
perature of approximately 1000° F. and effecting
is used in this process there is no excess localized
25 heating of the oil. By reason of that fact, and
substantial conversion of said vapors in said zone,passing the resulting highly heated vapors into an 25
the oil vapors of said stream to a cracking tem
the speed of travel of oil and vapors through the
enlarged externally unheated digesting zone in
relatively small pipes composing the cracking
which the vapors are maintained at a cracking
coils, no Ideposit of coke or carbon occurs in
them and the pipes are never fouled on that ac
30 count and are as clean at the close of a run of
temperature solely by the heat from the vapors
passed into said enlarged zone, maintaining a
any length‘of time as they were at the start,
thus permitting continuous operation with no
loss of time or expense to clean out the coils.
The temperatures and pressure specified both
35 may vary considerably according to the grade or
kind of oil being run through the apparatus at
Likewise the character of cracked
products obtained may be affected considerably
` the time.
` by variation of the rate of iiow of oil and vapors
40 through the system, as well as by the temper
atures and pressure obtaining in the cracking
zone. The temperatures and pressures claimed
are those which practice has found to be approx
imately average when treating Mid-Continent
45 oils but it will be understood that the method
could still be operated to advantage commercially
» at higher or lower temperatures and pressures
than those specifically stated above.
The invention having been thus described,
50 what is claimed as new is:
1. The process of refining and converting oil
herein described, consisting in preheating a con
tinuously flowing stream of oil gradually and
under high pressure, in heating this preheated oil
55 to a higher temperature while under high pres
sure and separating the vapors and residue while
under high but decreased pressure and prior to
substantial cracking, in further gradually heat
ing a rapidly flowing stream of said vapors at
pressure of from 200 to 500 lbs. per square inch in 30
said zones, maintaining the heating and cracking
conditions in said Zones such that a substantial
portion of said vapors are’converted to constitu
ents suitable as motor fuel, precipitating sub
stantially dry carbon from the vapors in said en
larged zone by decreasing the velocity of the
vapors introduced thereinto from said heating
and cracking Zone,> passing the resulting cracked
vapors from said enlarged zone, and recovering
a condensate suitable as a motor fuel from the 40
vapors passed from said enlarged zone.
4. The process of cracking mineral oils which
comprises passing the oil constituents to be
cracked While substantially all in vapor phase
in a confined stream and at high velocity 45
through a heating and cracking zone, heating
the oil vapors of said stream to a cracking tem
perature of from 950° to 1000° F. and effecting
substantial conversion of said vapor stream to
lower boiling constituents in said zone, passing
the resulting highly heated vapors into an en
larged digesting zone, passing the introduced
vapors through said enlarged Zone at a relatively
reduced velocity in substantially unobstructed
flow and precipitating therein only substantially '
dry carbon present or formed in the vapors intro
duced into said enlarged digesting Zone, main
taining a superatmospheric pressure in said
zones of two hundred pounds per square inch
60 a temperature in excess of 950° F. and under i and maintaining the vapors in said zones a suf
taining them at cracking pressures and tem
flcient length of time to convert a substantial
portion thereof to constituents suitable as motor
fuel, passing the resulting cracked vapors fromÍ
said enlarged zone, and recovering a condensate
suitable as a motor fuel from the vapors passed 65
from said enlarged Zone.
5. The process of converting mineral oil into
lower-boiling products, which comprises subject
high pressure to crack them in the vapor phase
by maintaining a forced circulation of a fluid
heating medium in indirect heat exchanging re
lation therewith, and in subsequently precipitat
65 ing substantially dry carbon from the vapors by
decreasing the speed of the vapors while main
2. In a process of converting oil, comprising ing mineral oil traveling in a stream of rela
70 heating a rapidly flowing stream of oil of re-; tively small thickness to heat at temperatures 70
below that at which substantial cracking takes
, stricted cross section to a temperature in excess
of 750° F. and separating the vapors generated place but sufñciently high to vaporize a desired
portion of said oil while leaving heavy constitu
thereby from unvaporized oil without substan
ents of the oil as liquid commingled with the
tial cracking, passing the separated vapors sub
stantially free from hydrocarbon constituents in vapors, separating such liquid from the vapors, 75
passing said'vapors at high velocity through a
heated coi1 and heating the vapors therein until
ditional cracking substantially only by the super
heat of said vapors passing said vapors through
a substantial proportion thereof has been con
said chamber slowly enough to permit separation
verted into lower boilingl point constituents,
of any carbon formed by the cracking to occur
maintaining the conditions of velocity and tem
and precipitating only substantially dry carbon
perature in said heated coil such that no sub
stantial deposition of carbon occurs from the
from the vapors introduced into said enlarged
chamber by the decrease in velocity of the va
pors passed therethrough, and recovering a rela
heating of the vapors therein, discharging the
vapors into an enlarged chamber wherein the
temperature is below that maintained in said coil
but is maintained suf?ciently high to effect ad
tively loW boiling condensate from the cracked
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