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Патент USA US2408587

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OEHKL'VI HUUU
F 195411
OR
294089584
Oct. l, 1946.
A. D. SMITH
2,
,584
HYDROCARBON CRACKING PROCESS WITH SUCCESSIVE ADDITION OF ADSORBENT
Filed Feb. 10, 1945
#N
Uil-NNUU
Patented Oct. 1, 1946
i 2,408,584`
UNITED STATES PATENT OFFICE
2,408,584
HYDROCARBON CRACKING PROCESS WITH
SUCCESSIVE ADDITIONS 0F ADSORBENT
Arthur D. Smith, Park Ridge, Ill., assignor to
g?‘nkins Petroleum Process Company, Chicago,
Application February 10, 1945, Serial No. 577,217
In Canada September 27, 1944
6 Claims.
1
(Cl. 196-55)
2
'I'he invention relates to an improvement in
process for treating hydrocarbons in the presence
An important object of the invention is to pro
vide, through such immediately above described
of certain ilnely divided adsorbents and particu
release of structural Water, a corresponding con
tinuous fresh contact surface in the thus pro
duced dehydrated or partially dehydrated adsorb
ent, partly through the formation of smaller par
ticles of adsorbent due to the -di'sintegrative ef
fect of the escaping Water vapor, and partly
through the formation of microscopic pores and
larly to a process for contacting petroleum hydro
carbons, lying outside of the boiling range of gaso
line and while obtaining under transforming con
ditions of heat and pressure, with intimately dis
persed ñnely divided hydrous mineral adsorbent
possessing a structural Water content substan
tially vaporizable under the transforming condi
tions employed.
fissures in the original particles.
A corollary object of the invention is to provide,
through such immediately above described for
mation of fresh contact surface, a corresponding
continuous augmented nascent adsorptive and/or
: catalytic effect; the advantage of such improve
A known process comprises among other fea
tures continuously subjecting a petroleum oil, in
which is suspended a finely divided mineral ad
sorbent towards carbon and carbon-forming sub
stance, to cracking conditions of heat and pres
sure, whereby carbon and carbon-forming sub
stance produced during the reaction is associated
with the adsorbent and prevented thereby from
depositing on the walls of the cracking apparatus 20
employed. Among suitable adsorbents recited in
such process, is the hydrous mineral adsorbent
calcium hydroxide; such being particularly an
adsorbent towards -sulphur-bearin asphalte s,
the ultimate degradation products of which are
carbon and hydrogen sulphide. 'I'he latter is neu
tralized by the hydroxide and the contaminating
ment being readily apparent where the dehy
drated or substantially dehydrated adsorbent, for
exa
„ntoni -actmcatalytically in improv
ing the yieldî‘?d/or quality of desired light hy
drocarbons. \\
Another object of the invention where, for ex
ample, the highly basic calcium hydroxide is em
ployed as the hydrous adsorbent, is to provide,
through the above described increased active con
tact surface in the adsorbent particles, for inten
siiied formation of calcium sulphide from hydro
gen sulphide commonly obtaining in petroleum
transforming operations; the continuous nascent
corrosive effect of the hydrogen sulphide on the
metal of the apparatus substantially reduced. It
liberation of structural Water increasing the ac
has been more recently discovered that the effl 30 tivity of the reaction.
ciency of such decontaminating action is in
Another object of the invention ancillary to the
creased by release of structural Water from the
immediately preceding is to reduce, through such
calcium hydroxide during the reaction, such re
above described intensified formation of calcium
lease producing fissures and pores in the hydrox
sulphide, the contaminating corrosive effect of
ide particles: or in short, forming additional ef 35 hydrogen sulphide on the metal of the trans
fective contact surface favorable to hydrogen sul
forming apparatus.
phide retention. While the general phenomenon
Of the several hydrous adsorbents that may be
of structural water release is inherent in the above
employed to develop the optimum in fresh active
described process, the actual percentage evolved,
surface contact through release of structural
and the stages in which evolution occurs, will vary 40 water, may be mentioned bentonite, bauxite and
with the cracking conditions imposed and the
the hydroxides of the alkaline earth metals, but
purity of the calcium hydroxide employel.; all
I prefer to employ bentonite Where catalytic ac
militating against the continuous nascent release
tion is a paramount issue, calcium hydroxide
of structural water during the entire or suo'stan
where intensified chemical action towards hydro
tially the entire cracking phase, and thus against
gen sulphide is wanted, and a mixture of the two
the optimum in eiiiciency of adsorptive effect.
where both effects are desired.
The present invention is an improvement over
In order that the invention may be more readily
the foregoing in that it provides not only for the
understood, reference is made to the accompany
continuous or substantially continuous release of
ing drawing of a flow diagram embodying a con
structural water from a hydrous adsorbent dis 50 crete example of one of the many operative con
persed in fluid hydrocarbon subjected to trans
ditions to which the invention may be applied.
forming conditions of heat and pressure, but for
Referring to such drawing, let it be assumed
such release during the entire or substantially the
a petroleum hydrocarbon, for example, gas oil,
entire period such hydrocarbon is subjected to
as supplied from the tank I through the line 2,
such transforming conditions.
is charged by the pump 3, through the line 4,
3
4
to the bubble tower 5, and that a composite virgin
gas and recycle oil therefrom, obtaining at '710°
F. (an incipient cracking temperature) and flow
ple per temperature rise being carefully recorded.
'I'he results of such a test applied to a techni
cal grade of calcium hydroxide of high purity un
der the transforming conditions previously de
scribed in the concrete example follow:
ing through the line 6 to the hot oil pump 1, is
introduced by such pump through the line 8 to
the transforming furnace 9.
Let it be further assumed that the oil, obtain
ing under 400 lbs. pressure, enters the radiant
coil I0 disposed in the'furnace 9, requires three
minutes for passage through such coil and dis
charges therefrom at 910° F., that the elliuent
.
Time
Temperature
Percent struc
Percent or total
interval,
differential,
tural water
(2g?ìä)wâîggc'
l 710- 800
1. 79
7. 37
minutes
F.
released
released
10
l
from coil I 0 enters the convection coil II, re
l
l 800- 850
6.17
25. 39
1
l 850~ 910
7.17
29. 50
quires ñve minutes for passage and discharges`
2
1 910- 950
0. 47
l. 93
therefrom at 1060° F., that the oil stream respec
1%
i 950-1000
0. 00
0. 00
1%
3 1000-1060
0. 00
0. 00
tively obtains at 950° F. and 1000° F. at return 15
bends I2 and I2', that the time factor between
8
710-1060
16. 60
64. 19
910° F., and 950° F. is two minutes, between
1 Radiant section period.
950° F. and 1000° F. one and one-half minutes,
2 Convection section period.
and that the final eiiluent from said convection
coil is released under reduced pressure through 20
From the above it will be noted that under
the line I3, as controlled by the pressure release
the time factor involved, release of structural wa
valve I4, to the evaporator I5 (after first hav
ter from the hydroxide in question practically
ing its temperature lowered in the heat ex
ceases between 910° and 950° F. A second dehy
change means I6) to incipient transforming con
dration test is therefore conducted on a. fresh
ditions; it fbeing noted that `the oil is thus sub 25 sample of the hydroxide, the chrome alloy tube
jected for a total period of eight minutes to trans
being previously preheated t0 910° F. before in
forming conditions of heat and pressure embrac
serting the sample, and the time factor between
ing a range of 710° F.-l060° F. Heavy residual
910° and 1060° F. maintained at five minutes.
oil containing spent adsorbent, whose introduc
Such test, due to the higher initial temperature
tion yto the system will be subsequently discussed, 30 involved, will generally result in substantially
is withdrawn from the Ibottom of the evaporator
the same total quantity of water being expelled
through the line I1 and cooler I8, as controlled
as in the first preliminary test; occasionally be
|by valve I9, to the fuel oil tank 20; while light
tween the range of 910° and 1060° F., but more
fractions separated in the evaporator pass
often between 910° and 1000° F., thus requiring
through the line 2I to the bubble tower 5 in 35 a third addition 0f hydroxide to bridge the final
which gasoline and distillate vapor are separated
gap of aqueous evolution between 1000° and
from recycle oil; gasoline passing through the
1060° F.
line 22 and condenser 23 to the tank 24, distil
Therefore, to comply with the invention and
late through line 25 and condenser 26 to the
ensure a continuous release of structural water
tank 21, and the recycle oil admixed with the 40 from
the 0.6 lb. of hydroxide over the entire or
virgin gas oil introduced through the lbubble tow
substantially
the entire 710°--1060° F. range, it
er, forming the composite charging stock to the
will be necessary in the first case to continuously
transforming coil in the manner as above de
introduce the hydroxide in two portions, one,
scribed.
when the oil stream obtains at '710° F., the other
While a'ny one, or a mixture of two or more
between 910° F. and 950° F.; in the second case,
of the previously mentioned hydrous adsorbents,
in three portions, with the oil stream obtaining
depending on the adsorptive and/or catalytic
at '710° F., between 910° F. and 950° F., and at
effect desired, may -be employed under the above
1000° F. respectively. To further ensure the
described operative conditions, let it be further
optimum in adsorptive and/ or catalytic effect, the
assumed a technical grade of calcium hydroxide
said portions of adsorbent should generally lie in
of high purity is actually used in the above case,
the same ratio to the total quantity introduced,
in quantity 0.6 lb. of hydroxide per bbl. of oil
as the corresponding time factor per temperature
charged to the coil; the specific problem being
interval of injection is to the total time factor
to so introduce such quantity of hydroxide as to
of the transforming conditions employed.
ensure a continuous nascent release of structural
Introduction of adsorbent to the system may be
water therefrom over the entire or substantially
effected in dry form dispersed in a hydrocarbon
the entire transforming range of 710° F.-1060° F.;
vapor carrier such as heavy naphtha vapor; or
or otherwise expressed, to ensure the optimum in
as a slurry suspended in a carrier oil conveniently
fresh active contact surface of adsorbent over
of the same grade as to be transformed.
such period.
GO
Referring again to the accompanying drawing:
To achieve such effect, I first subject a care
28, 29 and 30 represent a plurality of any num
fully weighed sample representative of the ad
ber of slurry tanks as may be desired, such tanks
sorbent to be employed, say 5 grms., to a pre
being ñtted with mechanical agitating means
liminary dehydration test in a current of dry
(not shown) and supplied with carrier oil
hydrocarbon gas such as methane; the test sam
through
the line 3I, by pump 32, from tank I;
ple preferably obtaining as a thin layer in a.
valves 28', 29' and 30’ serving to control the flow
platinum boat disposed in a chrome alloy tube
of such oil to said tanks. The latter are con
heated by an electric furnace, with the heating
nected through the grid manifold 33, as controlled
tube connecting to a water cooled condenser fitted
by valves 34, 34', 34", 35, 35', 35", 36, 36', 36”,
with a graduated receiver. The above test is 70 to the separately operated high pressure pumps
further conducted under the pressure, tempera
31, 38 and 39; such arrangement permitting feed
ture and time factor of the transforming rela
from any one or all of said tanks -to any one or
tions to be imposed on the hydrocarbon in which
all of said pumps. 'I'he latter are further iitted
. the adsorbent is to be employed; the percentages
with individual automatic controls of a well
of structural water released from the test Sam
known type (not shown) which can be set so -that
ötAHUH liUUil
5
2,408,584
the .pumps will continuously deliver predeter
mined volumes of slurry to the transforming coil
through lines 40, 4| and 42, respectively equipped
with check valves 40', 4|' and 42'; such injection
lines being depicted in .the accompanying drawing
as connecting to said coil at the predetermined
points described in the concrete example. In
such example, the slurry may be batch prepared
6
mixture, that under the time factor involved,
such aqueous evolution occurs in the said higher
temperature brackets, thus closing the gap re
quired to be ñlled by multiple introduction where
a single grade of hydroxide is employed.
In like manner to the specific example given
for calcium hydroxide, preliminary dehydration
tests may be applied to any of the hydrous ad
in tanks 28 and 29 and withdrawn from one tank
sorbents mentioned herein, orto those of similar
while the other is being reillled; or it may be 10 class, and from the structural water release data
pumped entirely from one tank, i. e., tank 28,
which is continuously supplied with carrier oil
and calcium hydroxide in the proper proportions.
Further assuming such slurry to be of a concen
thus obtained the number of multiple introduc
tions and points of injection necessary lto effect
a substantially continuous aqueous release over
an entire predetermined transforming range can
tration, say of 0.75 lb. of hydroxide per gallon 15 be readily determined. It will also be aplliarentl
of carrier oil and to obtain in tank 28, it may be
to those skilled in the art that increments of two
respectively introduced therefrom by pumps 3l
or more dliferent adsorbents of the class de
and 38 to the radiant and convection sections of
scribed, such as for example, bentonite and cal
said coil at the herein described predetermined
cium hydroxide, may be introduced pre-mixed at
temperatures, after closing valves 34', 34”, 35',
35", 36, 36', 36" and opening valves 34 and 35.
’I'he said pumps 3l and 38 may be set to contin
20 one or more predetermined points of the trans
nforming coil, or separately injected at a plu
rality of points; the specific point or points of
uously deliver their respective slurry increments
injection depending on preliminary dehydration
in the same quantitative ratio as the time fac
tors given in the concrete example; i. e., so that
data and the specific objective .to be obtained,
Within the thesis of effecting a, continuous or
0.225 lb. and 0.375 lb. of calcium hydroxide (total
substantially continuous release of structural
0.6 1b.) per barrel of oil charged to the coil, will
water from the adsorbent introduced over the
respectively enter said radiant and convection
particular .transforming conditions involved.
sections. By opening valve 36 and thus permit
The invention is further not limited to the ap
ting pump 39 to function, increments of 0.225 30 paratus, pressures, temperatures, time factors,
lb., 0.200 lb., and 0.175 lb. of hydroxide (total 0.6
quantities and ratios disclosed herein which are
lb.) may be respectively injected under the time
to be considered as illustrative only of one set of
factors and at the coil section points described
conditions comprehended by the invention, and
herein; although it is to be understood that ln
what I claim as new and desire to protect by 1ct
crements of adsorbent introduced may be in dis 35 ters Patent is:
‘
proportionate relationship to the time factors
1. Process of minimizing corrosion in an oil
involved.
cracking still, which comprises: supplying to the
It is to be further understood the percentages of
stream undergoing heating, successive increments
structural water released for a given temperature
of an adsorbent consisting essentially of calcium/
in 4the above described preliminary dehydration 40 hydroxide and adapted to react with corrosive
tests are illustrative only, since another calcium
compounds generated by decomposition of ingre
hydroxide of practically the same technical purity
dients in the oil; and timing said increments so
and tested under identical conditions, but de
as to add each increment at substantially the time
stone, or calcined‘ and/or slaked at a different
that the previous increment ceases to liberate
rived, for example, from a finer grained lime 45 structural water.
temperature, or rate, may show figures at vari
2. Process of minimizing corrosion in an oil
ance from those given; therefore the necessity for
cracking still, which comprises: supplying to the
separate preliminary dehydration .tests on cal
stream undergoing heating, successive increments
cium hydroxides from different sources to deter
of an adsorbent consisting essentially of a, finely
mine their proper injection points. In any case, 50 divided hydrous mineral adsprlìent having the
however, no unit lot of calcium hydroxide has
characteristic of liberating its structural water
been found, that when continuously introduced,
will release structural Water over the entire or
gradually when heated to oil-conversion temper
atures; and timing said increments so as to add
substantially the entire transforming conditions
each increment at substantially the time that the
herein disclosed; hence .the need of multiple in 55 previous increment ceases to liberate structural
troductions of such hydroxide to attain the
water.
'
optimum in fresh active surface contact and the
3. Process of minimizing corrosion in an oil
ensuing benefits thereby.
cracking still, which comprises: supplying to the
As a simpler alternative to multiple introduc
stream undergoing heating, successive increments
tion of a single grade of calcium hydroxide, one 60 of an adsorbent consisting essentially of calcium
continuous injection may be employed of a mix
hydroxide and adapted to react with corrosive
ture in suitable proportions, as determined by
compounds generated by decomposition of ingre
preliminary dehydration tests of the order herein
dients in the oil' timing said increments so as to
described, of calcium hydroxide of the technical
add each increment at substantially the time that
purity discussed and a calcium hydroxide `con 65 the previous increment ceases to liberate struc
taining over 1%, and preferably between 3 and
tural water; and pre-determining the timing for
8%, of calcium carbonate, that will release struc
said increments by exposing a sample of said
tural water over substantially the entire trans
adsorbent to a time-temperature and pressure
forming range herein disclosed. Such phenom
history substantially the same as in the still, under
enon is due to the fact that the presence of a 70 an atmosphere of hydrocarbon gas.
relatively small quanti-ty of carbonate, or car
4. A process according to claim l in which a
bonic acid derived therefrom and released dur
i fraction of calcium hydroxide contaminated with
ing the reaction in the high temperature brack
a significant percentage of calcium carbonate, up
ets. so retards the evolution of structural Water
to 8%, is included in the materials supplied.
from the carbonate-containing component of the 76 5. In an oil cracking process in which the con
2,408,584
7
tinuous progressive exposure of fresh reactive
surfaces of adsorbent lime is advantageous, the
novel procedure of making successive additions of
calcium hydroxide, and timing the successive ad
ditions so that each addition is made substantially
at the time that the previous addition ceases to
evolve water.
8
novel procedure of supplying the adsorbent in
the form of particles which gradually and pro
gressively evolve vapor, and by such evolution
clean and expose fresh reactive surfaces during
the period of vapor release; and timing the suc
cessive additions so that each addition is made
substantially at the time that the previous addi
6. In an oil cracking process in which the con
tion ceases to release vapor.
tinuous progressive exposure of fresh reactive
surfaces of an adsorbent is advantageous, the 10
ARTHUR D. SMTI‘H.
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