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Патент USA US2131169

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Sept. 27, 1938.
" _
E. F. ENGLISH
2,131,169
CRACKING AND~EXTRACTING HYDRÓCARBON OILS WITH A' SELECTIVE SOLVENT
Filed Nov. 21, 1954
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CRACKING AND EXTRACTING HYDROCARBON OILS WITH A SELECTIVE SOLVENT
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Patented Sept. 27, 1938 7
I,2,131,169
UNITED vSTATES
_PAT-ENT OFFICE
2,131,169
CRACKING AND EXTRACTING HYDROCAR
BON OILS WITH A SELECTIVE SOLVENT
Edward F. English, Baton Rouge, La., assignor to
Standard Oil Development Company, a. ccrpo- ,
ration of Delaware
Application November`21, 1934,'$erial No. '154,026
1 claim. (c1. 19d-5o)
This invention relates to a process of treating
hydrocarbon oils, such as the various mineral
withdrawn from the unit-through cooler I2 or
passed to a solvent extraction unit. The bubble
oils including petroleum oils, shale oils, oils ob'
tower Il is provided with eiilcient fractionating
tained in the low temperature carbonization ofv
5 coal, hydrogenated Aoily products, etc. by the
combination of a cracking and a solvent extrac
tion process, and will be fully understood from
the following description when read in con
junction with the drawing, the sole figure of
10 which is a diagrammatic side elevation partly
in section of an apparatus appropriate for carry
means, such as bubble cap plates, and serves for
the separation of the naphtha with the `desired
endpoint as overhead product. The naphtha
vapors are passed through the partial condenser
2 and final condenser I5, into the receivers I6
Ißa, provided with vents for the release of gases
through lines I1 and I8. Part of the naphtha is 10
returned to the top of the bubble tower II
`
through line I 1a as a reñux for the control of
The main object of the present invention is
the fractionation. The liquid product obtained
ing out the invention.
`
_to ysubject the hydrocarbon oil to a cracking
15 process, to separate a cycle stock from the
cracked products, this cycle stock being a dis
tillate product boiling higher than the naphtha
at the bottom of the bubble tower II is a cycle
stock which is run through heat exchanger I9 15
and cooler I9a into the mixing tank I4 of the
extraction unit. As cooling medium in cooler I9a
obtained in the cracking process, to subject this water or chilled brine or other suitable cooling
cycle stock to a treatment with a selective sol
medium may be used to reduce the temperature
v20 vent for separation thereof into a more paraf?nic of the cycle stock from bubble tower II to be
and a less paraiiinic product, and to subject these low that at which cycle stock and solvent are
two products to diñerent kinds of treatments.
completely miscible. The temperature 'at which
Referring now to Fig. 1, the same will be de
extraction is carried out is selected'to give the
scribed in conjunction with the method of op
desired character of extract and/or raii‘inate.
25'erating» the apparatus illustrated. The fresh The selective solvent from storage tank 20 `is
feed, such as for example, gas oil, is pumped from passed to the mixer I4 and thoroughly admixed
storage tank I through partial condenser 2 and with the cycle stocks, after which the mixture
heat exchangers 3 and 4 into the accumulator ' is forwarded to the settling tank 2| in which
5. The raiilnate from the solvent extraction step separation into two layers, 'viz, railìnate layer
30 is also passed into the accumulator, as will be and extract layer takes place. The/so-called
described hereinafter. 'I‘he mixed feed from raffinate layer consisting of the more parañinic
the accumulator is fed through high pressure constituents< of the cycle stock _together with
intercondenser 6 and heating coil 1 into the some dissolved solvent, is reheated in reboiler
soaking drum or reaction chamber 8. The mixed . section 22 arranged in the saine furnace as heat
36 feed is heated' to the cracking temperature in ing coil 1, and then discharged into the strip
coil 1 and undergoes the desired extent of, crack-` ping tower 23 on which a vacuum is preferably
ing in the soaking drum 8. A limited amount of maintained. The selective solvent is` obtained as
cracking usually takes place in the heating coil. overhead vapor condensed in condenser 24 and
If- desired, the soaking drum may be omitted returned to the selective solvent tank 20. The
4l) from the circuit, the coil temperature being solvent-free raiiinate is then passed to fthe ac
raised to increase cracking in the heating coil cumulator 5 for recracking. Alternatively, all
or part of the raiiinate may be removed from the
and compensates for loss of cracking in the soak
ing drum. The cracked eiiiuent from 8, after system through line 25 into ‘a storage tank (not
partial release of the pressure, is discharged into shown) and used for themanufacture of Diesel
45 the separator 9 which may be provided with oil, heating oil or similar products. -The ex
tract layer which consists of the selective solvent
' various fractionating devices, such as discs and
doughnuts.- Tar is withdrawn from the separator and non-paraiiinic constituents extracted from
through cooler III into a storage tank (not the cycle stock is reheated in heat exchanger I9
20
25
30
35
.40
45
.
shown). Vapors from the separator ipass and then passed through the release valve 26
50 through the high pressure intercondenser 6 and, . to tower 21. -In this tower the selective sol 50
y through heat exchangers 3 and 4 into the lower vent is taken overhead, condensedin condenser
part of a. bubble tower II. Part of a heavy cycle
stock condensed in intercondenser 6 and/or part
of the cycle stock from heat exchangers 3 and 4
55 may either be returned to the separator 9 or
28 and returned to the mixer I4 or storage tank
20. If the desired temperature of vextraction is
below that obtainable by water cooling, other
suitable cooling medium may be used in an 55
.2
~2,131,169
auxiliary cooler subsequent to condenser 28 to
further cool solvent before return to mixer Il.
The extract removed as bottoms from tower_
21 is introduced into the vacuum stripper 29
in which the remainder of the selective solvent
is removed as overhead product condensed in
condenser 30 and returned to the storage tank
20. 'I'he extract is removed from the bottom
of the stripper 29, cooled in cooler 8| _and then
10 passed to `a storage tank 34 for various uses to
be explained further below. Alternatively, the
extract may be subjected to cracking under con
ditions different from those used in the cracking
of the mixed feed. Other methods of utilizing
15 the extract are shown diagrammatically'and con
sist of either submitting the same to hydro
genation in the hydrogenation unit 35 or to a
chemical treatment in the chemical treatingunit
36.
20
=
» Referring to Figure 2, fresh feed is with
drawn from tank 50 by means of pump l5I and
forced through heating coil 52 in furnace 53.
The heated oil is then passed through line 54 into
a separator 55 fromV which the heavy tarry
parafllnic constituents. Usually the extract re
moved by the selective solvent contains the un
saturated naphthenic and aromatic constituents,
while the raffinate consists ofthe more parafllnic
constituents. We may cite phenol, the several
cresols, aniline, furfural, nitrobenzene, triphenyl
phosphate, triorthocresyl phosphate, liquid sul
fur dioxide, etc. as examples of selective solvents
which may be used in the carrying out of the
present process. Instead of one solvent a mix
or more of the selective solvent, thoroughly agi- '
tating the mixture, then allowing separation of
two layers to take place at a temperature below 20
that at which -the solvent becomes completely
.miscible with the oil. 'I’he raffinate layer and the
extract layer are- then separated from each other «
and the selective solvent is removed from both
The' layers, usually by means of distillation, but other
vapors ,from separator 55 are withdrawn through means, either physical or chemical, may also be
line 51 and introduced into a fractionating tower ì
The cracking part of the present process may
58, from which gasoline vapors are removed
through line 59, passed through a cooler Sllandk be carried out in the liquid phase at a pressure of
several hundred pounds per square inch, say be
thence passed through line 6| _into a gasoline stor
tween 250 _and 1,000 pounds per square inch,
age tank 62. 'I'he heaviest fractions in tower 58 are
withdrawn through line 63. An intermediate or even at pressures higher than that, or in the
vapor phase at comparatively low pressures ap
fraction or cycle oil is withdrawn from tower 58
proaching atmospheric pressure. The tempera
through line 64 and introduced into a counter
current extraction tower 65. A suitable selective ture may be any of the usual cracking tempera
tures or may be considerably higher than say
solvent contained in storage tank 65, is with
1,000c F. although, in many cases, it is pre
drawn by means of pump 61 and forced through
line 68 into the top of tower 65. Rañinate is ferred to carry out the present process at medium
removed from tower 65 through line 68 and temperatures, say between 800-l,000° F, The ar
rangement described above and illustrated in the
introduced into a still 10 in which the hydro
drawing is a tube and tank cracking system,
carbons are distilled from the solvent in the
event that the solvent used is higher boiling than but other systems may also be used. Further,
the hydrocarbon fractions. It will be understood the arrangementl shown may be modified in
that if the solvent used is lower boiling than the various ways; thus, for example, when the fresh
hydrocarbons, the solvent will be distilled from feed is a dirty stock, such as a topped crude, it
the hydrocarbons in still 10. The hydrocarbon may first be preheated and then fed into the
vapors are removed from still 10 through line separator 9 Ainstead of into the accumulator 5.
1l and after passing through a vcooler 12, are
The raiiinate is usually returned to the crack
passed through line 13 into the fresh feed tank ing system as a cycle stock and fed for this pur
50. The solvent is removed from st_ill 10 through pose into the accumulator 5. However, part or
line 14 and returned to the solvent supply tank the whole of the raffinate may be removed and
used for various purposes, such- as Diesel fuel,
86.
A
The extract is removed from tower 65 throug
heating oil, furnace oil, etc. The extract may
line 15 and introduced. into a still 16 in which be subjected to cracking under conditions dif-_
the solvent is separated from the hydrocarbons ferent from those used in the main cracking sys
25 products are withdrawn through line 56'.
used.
30
35
50
55
by distillation. As indicated above, if the solvent
is higher boiling than the hydrocarbons, the
latter will be vaporized, and if the solvent is
lower boiling than the hydrocarbons, the solvent
will be vaporized. The hydrocarbon vapors are
removed from still 16 through line 11 -’and col
lected in extract storage tank 18. The solvent is
removed from still 15 through -line 19 and re
turned to the solvent supply tank 66.
The extract is Withdrawn from tank 18 by
pump 80 and passed through line 8| into a
second heating coil 82 in furnace 83, wherein
the extract is cracked at a higher temperature
than the fresh paraiiinicfeed oil in heating coil
70 52. The heated oil from coil 82 is passed through
line 84 and merges with the heated oil from
coil 52 flowing through line 54.
The selective solvent may be any of those
' known to be effective in the separation of a
hydrocarbon oil 'into more parailinic and less
10
ture of them may be -used; for example, a mix-v
ture of phenol with cresols. The action of the
selective solvent may also be modified by the ad
dition of other organic or inorganic solvents
such as, for example, water, alcohols, glycol, etc. .15
'I'he `extraction step consists of mixing the cycle
stock to be extracted with, say, an equal volume
’
25
`
tem composed of heating coil 1 and soaking
30
35
40
45
50
55
drum 8. It may also be withdrawn and sub- '
jected to hydrogenation or to various chemical
treatments thus, for example, it may be treated
with sulfur for the preparation of wood preserva 60
tives, fùngicides and insecticides. It may also
be >treated with `,various inorganic oxides or sul
fides; for example those of arsenic, zinc, mercury,
etc. for the same purposes.
By the present process the cycle stock is sep
arated into a rafiinateuwhich shows improved
characteristics for certain uses such as, for ex
ample, Diesel oil and an extract which again is
a more appropriate raw material for certain other
uses than the untreated cycle stock. To illus 70
trate the point the extract is a better raw ma
terial for treatment with sulfur than saturated
hydrocarbons, because the latter produce a
large amount of H2S in their reaction with
' sulfur.
The extract is also an excellent raw ma
75
2,131,169
terial for destructive hydrogenation' carried out-> obtained is approximately 6,550 gallons per hour.
' in the presence of a catalyst and in a vapor phase
3150 gallons per hour of gas are obtained from
at temperatures between 950-1050° .F. whereby
a naphtha having excellent solvent qualities is
obtained.
which 1315 gallons of gasoline and 1835 gallons
per hour of .stripped fuel gas are produced. The
cycle stock is submitted to a selective solvent
treatment (withrphenol) as a result of' which
.
~ The following examples are given to illustrate
the above:
v
there is obtained after the removal of the selec
tivesolvent, 6250 gallons per hour4 of ramnate _
and an equal' amount of extract. The rafllnate l
is returned to cracking in the circuit ‘I and 8.
10
.
1. A paraiiinic gas oil is cracked,‘ the -products
being gasoline, fuel oil, gas and cycle stock.
10 The ñrst three are withdrawn from the unit, the
cycle stock is subjected to'soivent extraction
. The extract is subjected to hydrogenation in
with a mixture of phenol and glycol and sep
arated into rañinate and extract.
the presence of a sulfactive catalyst at a tem- ` f
The rañlnate . perature of 750°-850° F. and a pressure of 3000
is suitable for cracking with a relatively high
15 gasoline yield and is therefore mixed with fresh
3500 pounds per` square inch. There are ob
tained 7000 gallons per hour of overhead product
feed and returned to the cracking process. The separable- by distillation into 4500 gallons per
extract is suitable for the production of high , hour of 400° F. endpoint gasoline and 2500 gal
octane blending stock and is cracked at high lons per hour of an excellent grade of water white.
temperature in the separate >crackling circuit distillate of 38°-40° A. P. I. gravity and.. above
32-33, the distillate from which latter cracking the boiling range of gasoline. The ‘gasoline o~b-. 20
may be blended with the primary cracking tained is of 56-60 octane number by the Co-oper
products or may be segregated for use as blend
ative Fuel Research Motor Method and highly
ing stock to improve the octane number of other susceptible to improvement of octane number by
the addition of tetraethyl lead. Alternatively they
2. 'I'he parafllnic gas oil may be cracked and 'extract may be subjected to sulfurization or other 25
25
separated into raffinate as Vin Example 1, the chemical treatment.
*_
rañinate being returned with fresh feed to the
My process may be modified in various ways.
cracking process. The extract being more re
Thus,-for example, different solvents may be used
active chemically than either the fresh feed or according to thevmiscibility of the fresh feed
distillates.
'
'
g.
with aniline.` In the foregoing specific example
the cycle stock subjected to extraction with phe
30 the ramnate is submittedl to sulfurization or
arsenication.
3. The
c gas oil is cracked and theraf
nol is such that separation of the rafiinate and
the phenol-extract mixture takes place at a
vflnate is returned to cracking as above. The
extract is a low aniline point stock and is suit
temperature above the freezing point of phenol.
35 able for destructive hydrogenation. If hydro
If the fresh feed'is misclble with aniline at a
genated at comparatively low temperatures, _say
relatively low temperature and the” cycle stock
subjected to extraction is completely miscible
below 900° F., it will yield from 30 to 40% of
gasoline and 90 to 80%l Vof excellent gas oil,
with phenol at the freezing p’oint of the phenol,
, cracking stock or high grade Diesel fuel. 1f sub
then a solvent of lower freezing point such as~
jected to destructive hydrogenation in the pres
aniline may be used. By the addition of a seo
40 ence of a catalyst at a temperature of say be
ond storage tanld similar tostorage tank 20,
tween 950 and 1050° F., it will yield solvents and , either of the two solvents may be kemployed ac
cording to the character of the cycle stock to be
`toxic oils, the former suitable` for the prepara
45
tion of varnishes and the latter for use as wood -.
subjected to extraction.
preservatives, disinfectants and as raw materials
Many other changes and modiiications of my
process willbe apparent to those skilled in the
art and the same is not to be limited by the spe->
ciñc example given for illustration but only »by
the following claim in which it is my intention
to claim all novelty inherent in the invention.
for thel manufacture of >explosives and dyes.
The following specific example will illustrate
my invention: 18,750 gallons> per hour of 30°
A. P. I. gas oil (completely miscible with aniline
at 175-185° F.) fresh feed are passed into the
50 accumulator 5, after being preheated in 2. 3 and
I to about 500° F. The mixed feed is pumped
from the accumulator at a temperature of about
440° F. and after being preheated in> the high
pressure heat exchanger 6 to about 540i’ F.. it is
56 passed through the heating coil 1 at the rate of
25,000 gallons per hour and then through the
vertical'soaking drum l in downward direction.
The cracking stock is heated in the coil to a'
temperature between 900 and 930° F. and a pres
sure bf between 250A and 1,000 pounds per square
inch is maintained on the Isoaking'drum. The
’ separator is 'under a pressure of 10o-150 pounds‘
What I claim is:
Y.
.
_
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`
'I‘he process of converting a Zas oil .into hydro
2 carbonsboiling within the gasoline range which
comprises subjecting the gas oil to vcracking un
der conditions suitable for the production of 'a
~ mixed product containing gasoline and cycle oil.
extracting the'cycle oil with a selective solvent ,
for aromatic hydrocarbons whereby a ramnate
and an extract are obtained, combining the raf
ilnate with the initial gas oil to be cracked, sub
iecting the extract to cracking at a higher tem
' perature than that' maintained in the nrst crack
ing step‘to produce agasoline of high octane
per square inch with a bottoms temperature of
70
number and higher boiling hydrocarbons. and `
merging. the products of cracking'from'the sec
between '700 and 825° F. The'aìn'ount of tar re
moved ~through cooler- Il is about2800 gallons _ ond-meitioned cracking step with the products
per hour. The bubble tower H is'under a pres- ofcra'oking _from the first-mentioned cracking
lsure oi .95 to 145 pounds per square inch, the Iter."
temperature at its top between 40o-450° l". and
at its bottom between S80-680° F. 'lha distillata
mwaanr.
Y”
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