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Патент USA US2410166

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2,410,166
Patented Oct. 29, 1946
g ‘I ”
[STAT
_
j' F‘Thomasi
rnocnss
Bi’Kimball,
:OVFFSIEPARATINQ
Hammond, Incl‘,
TOLUENEI
assignor to
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SinclairRe?nin'g Company, New York, N. Y., a
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corporation of Maine
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.
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"Application-May '1'4,1941>,,SerialNo.393,338
- H ,
3HCl'aims. (o1. goof-#674)
This invention relates to improvementsin the ‘
separation of, toluene from para?in hydrocarbons
of similar boiling point, and to the production of
quite pure toluene from its mixturésfwith parafe
?n hydrocarbons.
'
‘
k In the production of gasoline or other low'boil
the toluene from the high boiling para?‘m hydro
carbons, i. e., the kerosene or thelike, a rela
tively simple distillation operation in view of the
substantial di?ereri‘ce in boiling points. Sub
stantially allof the toluene may thus, be recov-z
erediin quite pure form,_e. g.,,98,% or better.’
ingv hydrocarbons from crude oil, there is pro
duced, in admixture with paraffin hydrocarbons,
substantial amounts of the aromatic hydrocar
' Thesecond prO-du'ct'the kerosene or wash oil
production of a distilled fraction having a boil-v
ing point about that of toluene, it can be more
_ or other high boiling hydrocarbon from the low
, boiling para?in hydrocarbons and toluene which
rei?inate, is subjected to distillationvto remove
the sulfur dioxide it contains, which is recycled,
bon toluene. By fractional distillation, i. e., the 10 and then is fractionated to separate the kerosene
itcontains, the lighter fraction being returned to
or less concentrated‘, with the production of, mix
tures of toluene and paraffin hydrocarbons‘which -
may contain around 30-,-,50% of toluene. Further
concentration by distillation‘ operations is im
, practical, and for this reas0n,'further concentra
the feed tov the system if its toluene content is
15 su?icientto warrant'this, and the heavier free:
1 tion beingrecycled.
Operation in ‘accordance with the invention
tion of the toluene is accomplished by selective
extraction with sulfur dioxide, which preferen
tially dissolves the toluene. In such" operations,
has importantadvantages in providing inexpen
containing naphtha to separate the toluene from
like from?light hydrocarbons’in the kerosene raf
?nate is simple because of .the relatively small
sive yet quite complete recovery of toluene in
highly puri?ed form from admixture with par
a?in ‘hydrocarbons of similar boiling point. The
however, di?iculties are encountered because of
?nal distillation for the separation of the toluene
the distribution ratios between the extract and
from kerosene or the like is easily carried out
the ra?inate layers.
.
' ‘
.
because of the wide difference in boiling points.
The present invention is directed to improve
ments in the sulfur dioxide extraction of toluene 25 fsimilarly,v the separation of the kerosene or the
the para?in hydrocarbons,
‘
'
'In accordance‘ with ‘the, present invention, a
mixture of toluene with para?in'hydrocarbonsof
similar boiling point‘ is subjected to extraction,
usually countercurrenhwith sulfur dioxide, and
after separation of the extract from the raf
proportion of light boiling hydrocarbons in this
' mixture.‘ In addition; because of this'small vol
ume of the lighthydrocarbons in this mixture,
they may be recycled to the feed, for recovery
of the toluene therein.
The invention will be further ‘described in con
'?nate,,_the extract, with or‘without the addition
nection with the appended drawing, which illus
of more sulfur dioxide, iswashed or counter-cur
rently extracted with a kerosene OI‘OthBI' paraf 35 trates in» a_ diagrammatic manner, apparatus
?n hydrocarbon oil of ‘substantially higher boil
ing T point than toluene!“ This'jwashin'g or lcolln
tercurrent , extraction of. the' naphthabxtract
with kerosene or other relatively'high boiling,v
7 suitable for the practice of the invention.
_> ‘In the apparatus illustrated, there is provided
a tower l0 divided into two sections 12 and I4,
packed in the usual fashion for countercurrent
,para?in hydrocarbon, causes the replacement, to 40 extraction of one liquid by another immiscible
in it. Liquid sulfur dioxide is supplied toward
a substantial extent, of the ‘light para?in hydro
the top of the: upper section l2 throughthe inlet
carbons carried’ by the extract with‘heavier pars
l6, ‘while the feed, containing toluene and paraf
a?in hydrocarbons, and results in .two products,
one being a sulfur dioxide extract containing
most of the toluene, a‘small proportion oflparaf
?n hydrocarbons of boiling point close to that of
- ?n hydrocarbons of ‘similar boiling point issup
plied somewhat below the middle of the upper
' section through the line [8.
The sulfur dioxide passes downwardly through
the tower countercurrent' to the hydrocarbon
feed, and extracts from the hydrocarbon sub
second being a ra?inate containing kerosene or
, other wash ‘oil. the light para?in, hydrocarbons 50 stantially all of the toluene which it contains.
The sulfur dioxide extract is removed from the
extracted from the’ sulfur dioxide extract and a
bottom of the upper section through the line 20,
small proportion of toluene and sulfur dioxide.
and as removed, it containsthe sulfur dioxide,
The ?rst product is subjected to distillation
nearly all of the toluene and a substantial
to remove the sulfur dioxide, which is recycled,
and then is subjected to treatment to separate 55 amount of para?in hydrocarbons having a boil
, toluene and‘a substantial‘r-proportion of paraf?n
hydrocarbons of higher boiling point, and the
2,410,166
3
ing point about the same as that of toluene.
The naphtha ra?inate taken from the top of the
tower through the line 22 contains most of the
paraffin hydrocarbon together with small
I claim:
1. The process of separating toluene from a _
mixture of toluene and parai?n hydrocarbons of
similar boiling point which comprises intimately
contacting said mixture with sulphur dioxide in
an extracting treatment, separating the com
amounts of sulfur dioxide and toluene. It is in
troduced into the sulfur dioxide still 24 in which
the sulfur dioxide is removed - for recycling
posite mixture; into two component parts consist
through the storage tank 26 while the hydrocar
ingfof a raf?nate phaseand a primary extract
bon bottoms are led through the line 28 for use
in gasoline.
The sulfur dioxide extract removed from the
phase, bringing said primary extract phase With
10 out removal of sulphur dioxide therefrom into
intimate contact with a paraf?n hydrocarbon
having a‘, boiling point substantially higher than
is supplied through the line 30 to the upper part
thatyof toluene in a washing treatment, separat
of the lower section of the tower. lierosene ,or , '1" i-ngithe produotsi‘of said washing treatment into
bottom of the upper section through the line 20 ; '
other hydrocarbon oil having a boiling point sub
two,‘ component parts consisting of a washed ex
stantially higher than toluene, for example, hav
tract component and a spent Wash oil component,
separating hydrocarbons having boiling points
ing a boiling range of 363-490'3 F. is ‘supplied to
the lower portion of this section through the line
.similar to'toluene from said spent wash oil com
32. The kerosene and sulfur dioxide pass through
ponent by distillation, and recovering toluene
the tower countercurrently and in intimate con 20 from said washed extract component by distil
tact, with replacement of most of the light par
affin hydrocarbons in the extract by heavier pare
lation.
'
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2. The process ‘of separating toluene from' a
mixture of toluene and para?in hydro-carbons of
'
similar boiling point which comprises intimately
The kerosene raf?nate is removed from the top
of this section through the line 34',‘ and intro—' 25 contacting said mixture with sulphur vdioxide in
an extracting treatment, separating the com
duced intothe sulfur dioxide still 36, where‘the
posite mixture into two component parts consist
sulfur, dioxide which it contains is removed and
ing of a ramnate phase and a primary extract
returned to the vsulfur dioxide tank through the
phase, bringing said primary extract phase with
lines.36 ‘and lit. The kerosene raf?nate contain
ing light hydrocarbons is then passedthrough the
out removal of sulphur dioxide therefrom into
af?n hydro-carbons from the kerosene. ' .
linel'ii! to the splitter or still 44‘ in which the light
hydrocarbons are removed from the kerosene.
The light hydrocarbons are passed. through the
intimate contact with a paraffin hydrocarbon
line 453 and introduced with the, original feed to
ing the products of said-washing treatment into
the upper section l2 of the column'l@,'_if it con
two component ‘parts consisting of a Washed ex
tract component and a spent wash oil component,
having a boiling point substantially higher than
that of toluene, in a washing treatment, separat—
tains suf?cient toluene to warrant further proc
essing for its recovery. The'kerosene fraction is
recycled through the line 138 to the lower section
separating hydrocarbons having boiling points
of the column ML
The kerosene washed extract is removed from
the bottom of the section ill through the line 50,v
and introduced into the sulfur dioxide still .52.
The sulfur dioxide removed in this still is recycled
through the line ‘Ml, while the hydrocarbon frac
tion containing kerosene and nearlyall of the
toluene is removed through the‘line 5t‘, treated
with acid in the acid‘treater 56 and then sub
jected to distillation in the still 58 to 'separate'the
similar to toluene from said spent wash oil com
ponent by distillation and returning the thus sep
arated hydrocarbons to the ?rst-mentioned ex
tracting treatment, and recovering toluene from
said washed extract component by distillation.
3. The process of separating toluene from a
mixture of toluene and para?in hydrocarbons of
similar boiling .pointwhich comprises intimately
contacting said mixture with sulphur dioxide in
an extracting treatment, separating the com
posite mixture into two component parts consist
toluene from the kerosene and any ‘heavier prod- . ~ ing of a ra?inate phase and a primary extract
line Gil as a relatively pure product which may
phase,‘ bringing said primary extract phase‘ with
out removal of sulphur dioxide therefrom and in
the absence of additional sulphur dioxide from
contain 98.5% or more toluene; '
an extraneous source into intimate contact with
ucts that may have been formed. The toluene
is removed from the top of the tower through the
"
'
Sulfur dioxide and kerosene to replace losses
may be supplied through the'lines 62‘ and 6.4, re-&
spectively.
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In operatiomfor each 10G“parts of'a' hydrocar
bon fraction containing about 40%itolue'ne, about
100 parts of sulfur dioxide and H50,‘ parts of kero
a paraiiin hydrocarbon having a, boiling point
substantiallyhigherthan that of‘ toluene in a
washing treatment," separating, the products fof
saidwashing treatment into two componentparts
consisting of a‘waished extract component‘ and
aspen't wash oil component, separatin'ghydro
sene may be used, with recovery of substantially 60 carbons having boiling points similarto toluene
all of the toluene as a 98.5% product.
_
> '
If desired, to reduce the amount ,of “toluene
removed through the line 34, additional'sulfur
dioxide may be supplied through the line 66, but
this is not necessary; particularly‘ifl the light
hydrocarbon separated‘ from’ theikero‘sene
still 44 is recycled to the feed.
'
"
the
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‘from said‘ spent wash oil component by distilla
tionand returning the thus separated hydrocar-f
bone, to ‘the ‘?rst-mentioned extracting treatment,
and recovering toluene‘ from said washed extract
component by‘ distillation. '
.. THOMAS E. KIMBALL.
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