вход по аккаунту


Патент USA US2412828

код для вставки
Dec. 17, 194,6.
Filed July 4, 1944
_,I I
Patented Dec. 17, 1946
Ernest A. Naragon, ÍSe-a-con, Ñ. Y.,‘assignor to The
Texas CompanyyNew York, N. Y., a corpora
tion or’ `l‘lelavvare i _
Application July 2i, 1944,;se?ia1’Nò. “straits
5 Claims.
(C1. 19e-isf o
l .
This invention relates to the preparation ofr`
aromatic hydrocarbons from hydrocarbon. mix
tures and particularly from naphtha hydrocar
bon mixtures.
The invention contemplates
processior ex- » Cil
tracting aromatic hydrocarbons fromfeed hydro- _t
carbon .mixtures of aromatics and non-aromatics »
which comprises subjectingfa feed hydrocarbon
mixtureV to contact with anfaluminum halide-hy- »
drocarbon .complex of the Friedel-Crafts type.¿4
The contact is. carried out under conditions so as
to forma primary extract-phase comprising oom-` .u
plex aromatic'hydrocarbons and 4some 4nor'i-varow- .u
matic` hydrocarbons .and a primary vraiiinataV
latter` combinations are apparently of more loose
character than the aromatic complex combina
Ifhav@ found ’that when extracting aromatic
`hydrocarbonsl from naphtha mixtures with an
aluminum(chloride-hydrocarbon complex the re
sulting .extract phase comprises complex and aro
matichydrocarbons` and the‘resulting mixture is
.alsorvmore-or .less saturated withV parañîn and
naphthene‘hydrocarbons. .It has been found that «
the parañin and .naphthene hydrocarbons re
tained inlthe extract _phase can be displaced
therefrom .by washing the. extract phase with a
saturated hydrocarbonwofl diiîerent boilingl range;
phase consisting essentially of non-aromatic hy T15 thatisboiling outside» the range of the aforesaid
drocarbons such as paraffins - and naphthenes.`
The raffinate phase is discharged and the extractA
phase subjected to contact with a `Wash solvent
under conditions solas `to displace non-aromatic 1
hydrocarbons retained `in vthe »primary extract i
phase, leaving asecondary extract phase. This1A
secondary extract phase, consisting essentially`
of complex, aromatic hydrocarbons, and a small
amount of wash solvent is .then subjected _to -con- y
tact with a further quantity of wash solventsoas Í
to displace from the complex aromatic hydrocar
bons which after separation from the Wash sol
vent lwill be in a highly concentrated form.
The process is particularly applicable to the
separation of aromatics from naphtha feed
hydrocarbon mixtures.. containing aromatics .
amounting to from 10 to .80% `by volume of the
feed mixture using an aluminum chloride-hydro- ,
retained hydrocarbons. l
'._i‘hewashing treatment .can be- carried out un- .
der conditions such that the retained non-aro-l
matic4 .hydrocarbons ,are displaced `without sub-v
stantial displacement. ofthe aromatic `constitu
ents., Also.V the washedçextractphase from which
the .retained paramns .and naphthenes have been
displaced‘can then be subjectedto further Wash- v
ing, using a larger solvent dosage so as to displace
aromatic ylfiydrocarbons from the complex.> The
complex now strippedof aromatic hydrocarbons.
can‘thentbe, recycled. for the extraction of fresh
feed hydrocarbon mixtures. ,.
Thus, in `accordance .with the'v invention, a pri
mary `extract phase comprising complex, aromat
ic hydrocarbons and some non-aromatic hydro
carbonshcoextensive in boiling range is¿washed
with a , saturated petroleum. hydrocarbon boiling`
carbon complex characterized by .having a heat u
infthe range eithersubstantiallybelow or‘sub
of hydrolysis of about 290 to 330 small calories per 35 stantially. abovey that ofthe extract hydrocarbons.
gram of complex.
The complex maybedthat obtained by reacting> ,
aluminum chloride with kerosene in the presence
of hydrogen chloride yat a temperature of` about
200to 250° F. However, thecomplex may com
prise that which is formed in situ during the op- .
eration of the process as a result of reaction bey
tween free aluminum halide anda small propor-V _
tion of the aromatic constituents of the hydrocar
bons> undergoing treatment.
n ‘feature of the process has` to do `Witlothe sep- Y,
Thelwashingis effected in two stages.. In the iirst
washingistage, Varelatively loWlsolyent dosage is
employed so astodìsplacethe non-aromatic ex
`„tract hydrocarbons, while` inthe second stage a
relativelymhign‘solvent dosageis employed so as
to j ~displace thearomatia extract .hydrocarbons
'rom the;> complex., The ,displaced hydrocarbons
removed from each washing «stage are subse
,._quently fractionated from the washsolvent liquid
with _which they maybe associated.
aration of aromatic hydrocarbons_from.non-aro-A ~
ReferenceA will now be made to the` accompany
ing drawing> showingadiagram of flow useful in
matic hydrocarbons which are coextensive in boil-_ u
carrying qutthe process.
ing range,v Aluminum halide-hydrocarbon{com-._`
aromatic hydrocarbons and‘this .solvent action
Referring to the drawing, a feed hydrocarbon `
mixture “such as naphtha or a naphtha fraction
boiling inthe _rangeabove about >175° F.. contain- -
may‘involve somecombination betweenthe alu- .
minum halide andaromatic hydrocarbons. How- ,.
drocarbons, isdrawnirom `a _source not shown .
plexes exert a high degree of solvent action upon
inguaboiitßç?volume per cent of aromatic hy-.
ever.. nQn-aromatia .hydrocarbons .also renato. -. A„and Hconducted .through ‘_a. pipe l' to the lower.. l
form combinations with aluminum halide, These 55 portion of a primary extractor 2. The extractor
4 _
mixture entering the extractor 2 through the
pipe I.
advantageously comprises a vertical tower through
which the feed hydrocarbon stream rises coun
tercurrently to a downwardly moving body or
As a result of the washing treatment in the
extractor I5, substantially all of the aromatic con
stream of complex liquid.
The complex liquid is introduced to the upper
portion of the extractorrthrough apipe 3 from
stituents extracted by ther complex from the
feed hydrocarbons in extractor 2 are displaced
to form a tertiary raf?nate which `is continu
ously discharged through a pipe i3 from the
The complex is introduced to the extractor
top of the extractor I5.
in the proportion of about 2 to 4 volumes of com
The stripped complex containing some wash
plex per volume of feed hydrocarbon mixture. 10
solvent liquid ,is continuously discharged from
The extraction in the extractor 2 is 'carried out
the bottom of the extractor I5 through a pipe I9
at a temperature in the range of about (iO-120° F.
and is recycled all or in part through a branch
and at a pressure which may be in the range
a source which will' be referred to later.
pipe 20 which communicates with the previously
from atmospheric to 200 pounds per square inch
mentioned pipe 3. ` That portionwhich is not re
cycled and which may be regarded as used com
Provision may be made for continuously dis
plex may be discharged from the system at this
charging used complex liquid from the system
in an amount substantially equivalent to the
‘ point.
Referring again to the secondary extractor It),
amount of fresh complex being formedy in situ.
the secondary raffinate is conducted through the
pipe l :tand may be recycled all or in part through
a branch pipe 25 and pipe I to the primary ex
As a result of the countercurrent contact oc
curring within the extractor 2, extract and raf
ñnatephases are formed. `The raflinate phase
tractor 2. In this way the small amount of aro- .
consists essentially of paraffin and naphthene
matic hydrocarbons that may be present inthe
hydrocarbons and is continuously discharged from
the top-of» the extractor through a pipe 1.
25 secondary rafñnate are extracted therefrom upon
further contact with the complex liquid. The.
The extract phase comprises complex and ex
recycled non-aromatic hydrocarbons are ulti
tract hydrocarbons, the extract hydrocarbons
mately discharged as raffinate >through the pipe 1.
amounting'to from about 80 to 90 volume per
On the other hand, provision may be made`
cent of aromatics, the remainder being non-'aro
matics. This extract phase is continuously drawn 30 for passing the secondary raffinate allor in part
Bvto a secondary extractor lil wherein it is sub
to _a fractionator unit 26 indicated in broken`
lines for the purpose of separating the Wash‘sol
jected to the first stage washing action.v
A wash solvent consisting essentially of sat
tional distillation. The‘aromatic hydrocarbons
olf from the bottom ofthe tower through a pipe
vent from the aromatic> hydrocarbons by frac
urated hydrocarbons boiling below 175° F; is con- ‘
ducted from a source not shown through a pipe
l2 to the lower portion of the extractor I0. The
wash solvent is introduced in the proportion of>
may be segregated as a plurality of separate frac
tions as indicated. In' such case, provision may
be made >for recycling the separated aromatic
fractions all or in part to the primary extractor 2. ,
The tertiaryl raflinateV discharged from the ex
of primary extract phase. The wash solvent rises 40 tractor I5_ through the pipe I8 is likewise passed '
to a fractionator 3€) also shown in broken lines.
through the tower countercurrently to the de
The tertiary lraffinate is also subjected 4to, frac
scending primary extract phase at a temperature
tional distillation in orderto recover hydrogen
in the range about 60 to 120° E'. and under a
chloride, and also to remove wash solvent from
pressure ranging from atmospheric to 200 pounds
about 1 volume of solvent to 10 or 15 volumes
the aromatic hydrocarbons.
Under these conditions the saturated extract
hydrocarbons which are coextensive in boiling
obtained as any number of separate fractions..
The separated wash solvent is recycled through
a pipe 3I 'tothe pipe I2 for reuse _in the pri-`
range with the aromatic'extract hydrocarbons are
The latter may be
displaced from the primary‘extract phase in the
form of a‘secondar‘y railinate.> This secondary 50
mary yand secondary washing stages._ '
raffinate is continuously discharged through a
of the extracted hydrocarbons leaving the primary i
pipe I3.
extractor 2 willbe about 82 to 87 volume per cent,
Thus vby way of example, the aromatic content
while the aromatic content ofthe final extract
hydrocarbons from the three stage system willY
primary extract vhydrocarbons and some wash 55 be about 91 to 97%. on the other hand, by omit
ting the secondary extraction, the ñnal extract Y
solvent. The wash solvent retained in the sec
from the fractionation unit will haveÍthe same
ondary extract phase will be approximately equal ,
composition as that ofthe extract hydrocarbons
in volume to the saturated hydrocarbons displaced
from the primary extraction. i
therefrom. It is continuously removed through
While mention has been made of using a wash
a pipe I4 and conducted to the upper portion of 60
solvent which is lower boiling than the feed hy
a tertiary extractor I5 which is advantageously
drocarbon mixture passing to the extractor 2,:
operated under conditions of temperature and
nevertheless it is contemplated that the wash '
pressure within the ranges described _for the sec
solvent'may be a hydrocar-bon or .hydrocarbon
ondary extractor I0.
Another stream of wash solvent liquid is con 65 Amixture boiling in the lrange above that of the
feed hydrocarbons. The object is to use a wash '
ducted from the pipe I2 through a branch pipe
The secondary extract phase accumulating in
the bottom of the extractor Iü comprises complex,
IS to the lower portion of the ~extractor I 5 and is
introduced thereto in the proportion of about 1
to 3 volumes of _solvent per Volume of secondary
solvent which is outside the boiling range of the
hydrocarbons which are to be displaced from the
complexand Vwhich subsequently can be. sepa
extract phase.
70 rated readily lfrom the displacedl hydrocarbons .
The volume of secondary extract phase flow- ` by fractional distillation. ..
ing through the ’pipe I d is substantially Vequal
to the volume of primary extract phase flowing
through the pipe 8 and will range from 2%"
to 51/2 times >the volume of feed‘hydrocarbon
The „feed rhydrocarbon mixture may be lany
naphtha fraction containing benzene'toluene and
higher A.rr'iole'cular ` weight hydrocarbons, and . it
7521s'v contemplated that the process may be ein».l
hydrocarbons, removing from the secondary ex
traction zone a secondary raffinate consisting
essentially of said Wash solvent and non-aromatic
primary extract hydrocarbons, passing the re
bon complex of the Friedel-Crafts type, forming
a primary extract phase comprising` complex,
aromatic and some non-aromatic hydrocarbons
and a primary raiiinateY phase consisting essen
moved secondary extract phase through a ter- i, tially of non-aromatic hydrocarbons, discharging
the primary raffinate phase, subjecting the pri
tiary extraction zone in countercurrent Contact
with another stream of said Wash solvent liquid
under substantially similar temperature condi
tions and in the proportion of about from 1 to 3
mary extract phase to countercurrent contact
with a wash solvent consisting essentially of Y
saturated hydrocarbons boiling below 175° F. in
volumes of solvent per volume of secondary ex- l 0 the proportion of about 1 volume of wash solvent
tract phase, removing from the tertiary extrac
per 10 to 15 volumes of primary extract phase,
tion zone a tertiary extract phase consisting es
effecting said countercurrent contact at a tem
perature in the range about 60 to 126° F. such that
non~aromatic extract hydrocarbons are displaced
from the primary extract `phase leaving a sec
sentially of stripped complex, removing from the
tertiary extraction zone a rañîinate phase con
sisting essentially of said Wash solvent and 1 0
aromatic primary extract hydrocarbons, recycling
ondary extract phase comprising complex, aro.
said stripped complex at least in part to the
matic primary extract hydrocarbons and a small
primary .extraction zone, fractionating from the
amount of Wash solvent, discharging the dis
placed hydrocarbons, subjecting the secondary
secondary and tertiary raiîinate phases said wash
solvent liquid and recycling the recovered wash 20 extract phase to countercurrent washing with a
solvent liquid to the secondary and tertiary ex
further quantity of said wash solvent in the
traction zones.
proportion of about from l to 3 volumes of said
5. A process for extracting aromatic hydrocar»
wash solvent per volume of secondary extract
bons from feed hydrocarbon mixtures of aromatic
phase under substantially similar conditions of
and non-aromatic hydrocarbons Which comprises 25 temperature such as to displace said aromatic
subjecting a naphtha feed hydrocarbon mixture
primary extract hydrocarbons from the complex,
boiling in the range above about 175° F. and con
and removing the displaced aromatic extract ~
taining Afrom about 10 to S0 volume per cent
aromatics tofcontact at a temperature of about
60 to 120° F. with an aluminum halide-hydrocar- 3 0
Без категории
Размер файла
685 Кб
Пожаловаться на содержимое документа