close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2071590

код для вставки
2,071,590
Patented Feb. 23, 1937
UNITED STATES PATENT OFFICE
2,071,590
PROCESS OF EXTRACTING LIGHT MINERAL
OIL DIST‘ILLATES WITH SULPHUR DI
OXIDE
Ernest W. Thiele and Fred W. Scheineman, Chi
cage, 111., assignors to Standard Oil Company,
Chicago, 111., a corporation of Indiana
Application March 23, 1934, Serial No. 716,970
7 Claims. (Cl. 196-—37)
This invention relates to the process of extract
ing light mineral oil distillates with sulphur di
oxide, and it pertains more particularly to the
extraction of light petroleum distillates such as
5 petroleum naphthas and cracked naphtha con
taining anti-detonating constituents with sul
phur dioxide for the purpose of separating the
anti-detonating portion of the naphtha from the
remainder thereof which is called the raflinate.
10
The object of our invention is to provide a novel
and ef?cient method for extracting petroleum
naphthas with a selective solvent such as sulphur
dioxide.
A further object of our invention is to provide
15 an extraction process whereby gaseous sulphur
dioxide can be absorbed in the naphtha to be
extracted.
A further object of our invention is to provide
an extraction process whereby the used sulphur
dioxide can be efficiently and cheaply recovered
and re-used.
Further objects and advantages of our process
will be apparent from the speci?cations when
read in light of the drawing which gives a di
agrammatic ?ow plan of our process.
Petroleum naphthas obtained by cracking heav
ier oils contain large proportions of hydrocarbons
and compounds which possess anti-detonating
characteristics or anti-knock properties. Petro
30 leum naphthas from other sources and processes
such as the hydrogenation of hydrocarbon oils
and polymerization of hydrocarbon oils may
contain varying proportions of anti-detonating
constituents which can be extracted by our proc
35 ess. Generally, the fractions of petroleum naph~
thas having an initial boiling point of about
240° F. and an end point oi 400° F. are preferable,
but petroleum naphthas with somewhat lower or
higher initial boiling points and lower or higher
end boiling points may be used. For example,'
naphthas may be used which contain from 5 to
20% of hydrocarbons boiling within the range
of 160 to 200° F., and from S5 to 95% of hydro
carbons which boil below 390° F. to 435° F.; said
45 naphthas may contain from 30 to 50% of anti
detonating constituents.
The quantitative amount of anti-detonating or
anti-knock constituents in the naphtha and ex
tract is expressed in octane numbers as deter~
mined by the CFR motor method described in
ASTM method D357-33T.
By way of example and illustration we will de
scribe the operation of our process when used
to extract a cracked petroleum naphtha having
.55 an initial boiling point of about 250° F. and
an end boiling point of about 400° F. The naph
tha to be extracted, or feed naphtha, is passed
from the naphtha feed tank 10 by the pump II
to the exchanger i2 wherein the naphtha is heat
ed or cooled to the temperature employed in the
step of dissolving gaseous sulphur dioxide in
the naphtha. In this case a temperature of 80°
F. was used. Any suitable heat exchanger me
dium such as water may be passed through the
line I3 to effect the desired heating or cooling 10
of the naphtha.
The naphtha is then dried by
a suitable means such as by passing it into the
lower part of the tower I4 where it rises through
a suitable drying agent such as sodium chloride,
silica gel, calcium chloride, or the like. The dried 15
naphtha is then passed by the conduit I5 to
the upper part of the absorber l6 and permitted
to descend through the absorber over the bubble
plates ll, or equivalent means.
Dry S02 gas, which may be mixed with air and
excess nitrogen, is passed by the conduit l8
through the exchanger I9 where it is cooled or
heated to about 125° F. bv a suitable heating or
cooling medium entering the exchanger through
conduit 20. Generally, the temperature of the 25
S02 gases entering the exchanger I9 is above
125° F., and water may be used to cool the gases
to the desired temperature. In this particular
example, the gaseous mixture entering line l8
contained about 90% oxygen and nitrogen and 30.
10% $02. It was cooled with water from a high
temperature to about 125° F. by the exchanger l9.
The S02 gas may be obtained by burning sulphur
or sulphur compounds as in the preparation of
sulphuric acid. The S02 mixture is then passed 35
by the blower 2! under a slight pressure of about
19 to 20 pounds per square inch absolute, through
the conduit 22 to the lower part of the absorber
i6 and there permitted to ascend through the
absorber and be absorbed in the feed naphtha. 40
If desired the pressure in the absorber I6 may
be raised to 3 or 4 atmospheres absolute. A perfo
rated pipe or an equivalent device may be used
for introducing the gaseous sulphur dioxide into
the bottom part of the absorber. After the sul 45
phur dioxide has been used to extract the naph
tha, a substantial portion thereof is recovered
in the gaseous phase by the SOz-separators 5|,
53, 14,81, H3, and M0 and recycled by the mani
fold 58 to the absorber it; these SOz-separators 50
and the recovery of the sulphur dioxide will be
described later. The absorption of the S02 gas
in the naphtha to be extracted tends to strip or
force some of the low-boiling hydrocarbons or
compounds out of the naphtha; so, in order to 55
2
2,071,590
avoid this, a small amount of a naphtha which
is somewhat heavier than the naphtha to be ex
tracted is passed from the storage tank 23 by
a pump 24 and conduit 25 to the top part of the
absorber I 8.
This heavier naphtha is introduced
into the absorber i§ at a point above the point
where the feed naphtha enters the absorber i8.
This heavy naphtha re-absorbs these light hy
drocarbons or constituents and prevents them
from escaping through the vent 26. Also, this
heavy naphtha tends to absorb any gaseous sul
phur dioxide which was not absorbed in the
naphtha. Generally, the temperature of the
heavy absorbing naphtha is somewhat lower than
15 the temperature of the naphtha being extracted,
and consequently a cool zone of liquid is main
tained in the upper part of the absorber HE. A
cooler may be placed in the line 25 to accomplish
this result. The vent stack 26 is provided on
20 top of the absorber for removing the undissolved
gases and air. An aspirator 260. may be placed
in the vent stack to mix air with the vented gases,
thereby rendering the admixture non-explosive.
2,5
The feed naphtha with dissolved sulphur di
oxide is removed from the bottom part of the
absorber l6 by the conduit 2'! and forced by
the pump 28 through the heat exchangers 29
and 30 and cooled to about 5° F. The feed naph—
tha is then introduced into the extractor 3! by
30 conduit 38a at a point intermediate the bottom
and center of the extractor. Liquid sulphur di
oxide is passed from the storage tank 32 by the
pump 33 at a pressure of about 65 pounds per
square inch absolute through conduit 35; to the
35 heat exchanger or cooler 35, where it is cooled
from atmospheric temperature to about 20° F.,
and thence into the upper part of chilling tower
36 where part of the liquid sulphur dioxide is
?ashed in order to cool the liquid sulphur dioxide
40 to a temperature within the range of about —5
to +5’ F. The pressure maintained in the chill
ing tower 36 may vary, but generally from 11
to 12 pounds per square inch absolute is satis
Recovery of sulphur dioxide from the S02
extract
The SOz-extract is withdrawn from the bottom
of the extractor Si by conduit 43 and forced
by the pump 44 into the heat exchanger 35 where
the temperature of the SOs-extract is raised from
about 5° F. to about 60 to 70° F. The heated
Soz-extract is then passed by the conduit 45 to
the heat exchangers t6 and 47, where it is fur
ther heated to a temperature within the range 10
of 70 to 80° F. in the ?rst exchanger and 90° to
100° F. in the second exchanger, and thence into
the evaporator (58.
The sulphur dioxide is removed from the ex
tract by a triple stage or multiple stage evap
orator in which the temperature and pressure
within each successive evaporator are progressive
1y increased. By this type of evaporation, we
effect considerable heat economy and operating
cost, and recover a substantial portion of the
sulphur dioxide in the liquid phase. The SO2~
extract entering the evaporator
is maintained
at a temperature of about 97° F. and a pressure
of about 73 pounds per square inch absolute. .,
The portion of sulphur dioxide that evaporates
under the temperature and pressure maintained
in evaporator 138 is removed from the top part
of the evaporator by conduit 49 and passed to
the condenser or heat exchanger 50, where it is
cooled to a lower temperature of the order of
about 90 to 92°
and thence to the SOs-separator
3!, where the lique?ed sulphur dioxide separates
from the gaseous sulphur dioxide and constit
uents. The sulphur dioxide entering separator 5|
is maintained at a temperature about 91 to 93° 35
F. and at a pressure of about 72-74 pounds per
square inch absolute. The liquid sulphur dioxide
is passed from the bottom of the separator 5|
through the cooler or heat exchanger 52, where
it is further cooled to about 85° F. or atmospheric,
temperature, and thence to the liquid-S02 mani
fold 53 where it is returned to the liquid-S02
factory. The vaporized sulphur dioxide resulting
storage tank 32 for further use in the extractor 3 l.
45 from the flashing is recovered by a compression
Any suitable cooling medium may be used in
unit to be described hereinafter. A portion of
the cold liquid sulphur dioxide is removed from
the bottom part of the chilling tower 36 by the
conduits 3i‘ and 38 and passed through the ex
some gaseous sulphur dioxide which are collected
in the top part of the separator 5| are passed
50 changer 32 to aid in cooling the naphtha entering
the extractor 3!; the S02 gas leaving the ex
changer 35 is recovered by the compression unit
described hereinafter. Cold liquid sulphur di
oxide is withdrawn from the bottom of the chilling
55 tower 36 through the conduits ST and 39 by the
pump iii} and forced into the top part of the
extractor 3i. The cold liquid sulphur dioxide
descends through the extractor 3! over the baffle
plates and/or bubble plates or packing s2, and
60 extracts the anti-detonating fraction of com
pounds and constituents from the ascending body
of naphtha containing dissolved sulphur dioxide.
The average temperature maintained throughout
the extractor 3| is generally around 5° F.; how
65 ever, higher or lower temperatures may be used,
ranging from 10° F. to —l25° F., although the
preferred temperature ranges are 5° to ~40° F. or
from —30° to —7 0° F. The material which passes
to the bottom or lowermost part of the extractor
70 3| comprises the suiphur dioxide extract or mix
ture of liquid sulphur dioxide and anti-detonat
ing constituents. The material which rises to
the top of the extractor 3| comprises the raf
?nate or extracted naphtha with some dissolved
75 sulphur dioxide.
the cooler 52.
The permanent gases containing 45
by conduit 54 to the pressure reducing valve 55
and thence into the gaseous-S02 manifold 56.
The S02 gas and permanent gases in manifold 60
58 are returned to the lower part of the absorber
l6 and reabsorbed by fresh feed naphtha. By
this step we are able to rc-use this portion of
the gaseous sulphur dioxide in the extraction
of naphtha without first liquefying the sulphur 55
dioxide. The reducing valve 55 reduces the pres
sure of the S02 gases entering the manifold 56
to about the pressure of the gases entering the
lower part of the absorber through conduit 22,
that is, about 19 to 20 pounds per square inch ab— 60
solute; however, it should be understood that
lower or higher pressures can be used.
The SOs-extract or bottoms in evaporator 48,
from which some sulphur dioxide has been re
moved, is removed from the bottom thereof by
the conduit 5".’ and forced by pump 58 under a
higher pressure to the heat exchanger 59, where
it is heated to a higher temperature, and thence
to the second evaporator 68. The SOz-extract
in the evaporator 38 should be maintained at a 70
temoerature of about 124° F. and a. pressure of
about 111 pounds per square inch absolute. The
portion of sulphur dioxide which evaporates un
der the temperature and pressure maintained in
75
2,071,590
the evaporator 60 passes through the conduit
6| to the heat exchanger 41, where it heats the
fresh S02-extract entering the evaporator 48, and
‘thence through conduit 62 to the SO2-separator
63 where the lique?ed S02 separates from the
gaseous S02. The materials in separator 63 are
maintained at a temperature of about 116° F. and
ya pressure of about 111 pounds per square inch
. absolute.
The lique?ed sulphur dioxide is re
10 moved from the bottom of the separator 63 and
passed to the cooler or heat exchanger 64, where
it is cooled to about 85° F. or atmospheric tem
82. The pressure reducing valve 18 releases the
liquids into conduit 19 at a pressure of about 75
pounds per square inch absolute and this pres
‘sure is maintained within the ?ash drum 82.
The heat exchanger or heater 89 adds sufficient
heat to the S02 extract or bottoms to practically
compensate for the cooling effect caused by the
flashing of the sulphur dioxide in drum 82. The
temperature in the ?ash drum 82 is maintained
at about 180° F. The flashed S02 gas passes 10
through the conduit 83 to the heat exchanger
perature, and thence to the lique?ed-S02 mani
fold 53. The liquid sulphur dioxide entering the
15 manifold 53 is returned to the storage tank 32 for
further use in the extractor 3|. The permanent
‘gases containing gaseous sulphur dioxide which
collect in the top part of separator 63 are passed
by conduit 65 to the pressure reducing valve 66
20 and thence into the S02-gas manifold 56 where
they are returned to the lower part of the ab
84, where it is cooled by a suitable heat exchange
fluid, such as water entering the conduit 85, and
thence through the conduit 86 to the S02-sep
arator 87. The sulphur dioxide in separator 61
is maintained at a temperature of about 93° F.
and a pressure of about 75 pounds per square
inch absolute. The lique?ed or condensed sul
phur dioxide is removed from the bottom of the
separator through the heat exchanger or cooler
83, where it is cooled to about 85° F., or atmos
sorber l6 and reabsorbed by the fresh feed naph
',tha. The reducing valve 66 reduces the pressure
of the S02 gas entering the manifold 56 to about
25 the pressure of the S02 gases entering the lower
part of the absorber through the conduit 22; for
example, about 19 to 20 pounds pressure per
square inch absolute.
The S0‘2-extract, from which some of the sul
30 phur dioxide has been removed, is passed from
the bottom of the second evaporator 66 by con
duit 61 and forced by pump 68 under a higher
pressure to the heat exchanger 69, where it ‘is
heated to a higher temperature by a suitable
35 heat exchange medium entering conduit 16. Ex
haust steam may be used as a suitable heat ex
change medium for the heater 69. The extract
is then passed to the evaporator ‘H. The S02
extract in evaporator ‘H is maintained at a tem—
40 perature of about 182° F. and a pressure of about
200 pounds per square inch absolute. The por
tion of sulphur dioxide which evaporates from
evaporator ‘H under the temperature and pres
sure prevailing therein passes through conduit
45 12 to the heat exchanger 59, where it heats the
S02 extract passed from evaporator 48 to evap
orator 60, and thence through conduit 13 to the
S02-separator 14 where the lique?ed sulphur
dioxide separates from the uncondensed sulphur
50 dioxide.
The sulphur dioxide in separator 14 is
maintained at a temperature of about 157° F. and
‘a pressure of about 200 pounds per square inch
absolute. The lique?ed sulphur dioxide removed
‘from the bottom of the separator 74 is passed
55 through the heat exchanger 15 and cooled to
about 80° F. or atmospheric temperature, and
:thence to the manifold 53 where it is returned
to the storage tank 32. The gaseous sulphur di
oxide and gases which collect in the top part of
60 the separator 74 are passed by conduit 16 to the
pressure reducing valve 71 and thence into the
SO2-gas manifold 56 where it is returned to the
lower part of the absorber l6 and re-used to ex
tract the fresh feed naphtha. The reducing valve
65 11 reduces the pressure of the S02 gas entering
the manifold 56 to about the pressure of the S02
gas and air entering the lower part of the ab
sorber through the conduit 22; for example,
70
3.
about 19 to 20 pounds per square inch absolute.
The S02-extract or unsaturated compounds re
maining in evaporator ‘H is withdrawn through
the pressure reducing valve 78 and passed by the
conduit ‘I9 to the heat exchanger 80, where the
S02-extract is heated. This heated extract is
75 then passed through conduit 6| to the ?ash drum
pheric temperature, and thence to the liquid-S02
manifold 53. The gaseous sulphur dioxide or
uncondensed gases removed from the top of the
separator 67 pass by conduit 89 to the pressure
reducing valve 96 and thence into the S02-gas
manifold 56 where it is returned to the absorber
l6 and redissolved in the fresh feed naphtha.
The pressure reducing valve 99 reduces the pres
sure of the S02 gas to about the pressure of the 0
S02 gases entering the lower part of the ab
sorber [6.
The S02-extract which has had a substantial
proportion of the sulphur dioxide removed, is
passed from the flash drum 82 by conduit 91 s
through the pressure reducing valve 92, to the
upper part of the extract stripper 93 and per
mitted to descend through said stripper over the
baffle plates, bubble plates or packing material
94 disposed therein. The S02-extract near the 40
bottom of the extract tower is trapped out by
the tray 95 and passed by the conduit 96 through
the heater 97, and returned to the stripper at a
point below the trapout plate 95. The heater
9'! raises the temperature of the extract passed 45
therethrough to a temperature of about 260° F.
The pressure in the vapor space 98 or top part of
the stripper should be maintained at about 7.5
to 8 pounds per square inch absolute. The
stripped S02 gas and some extract vapors pass 50
from the top. of the stripper through conduit 99
to the condenser I00 where a substantial propor
tion of the vaporized extract is condensed and
returned through conduit lol. This returned
condensate or reflux is usually at a temperature
of about 100° F‘. The uncondensed gases leaving
the condenser 16!! are passed by conduit I02 to the
gas compressor unit and lique?ed; this gas com
pressor unit will be described hereinafter.
The extract or anti-detonating constituents
which are now free from sulphur dioxide are
removed from the bottom of the extract stripper
93 through the conduit M3 by the pump I04 and
forced through conduit I65 and heat exchanger
46 to the extract storage tank I06. If desired,
the extract may be washed with an alkaline
solution to remove any trace of sulphur dioxide
before the extract is blended with gasoline or
motor fuel in order to- raise the anti-knock value
of said fuel. Also, the extract may be recom 70
bined with a part of the raflinate resultingv from
the process, or the ra?’inate may be cracked and
then combined with the extract. If desired, the
extract may be further treated before being
blended with a motor fuel; for example, it may
4
2,071,590
be given a second extraction with S02 or other
solvents.
In the above description of the recovery of
sulphur dioxide from the SOz-extract, we have
set forth speci?c temperatures and pressures for
this process, but it should be understood that
other temperatures, pressures and conditions may
be used without departing from the scope of our
invention. The particular‘ temperature and
10 pressure used will vary somewhat with the mode
of operating the process and the nature of the
naphtha extracted.
Sulphur dioxide recovery from the ra?inate
The cold ra?inate removed from the top of the
extractor 3! is passed by the conduit I0‘! and the
pump I08 through the heat exchangers 29 and
I09, where it is heated to about 190° F., and
thence to theflash drum H0. The ra?inate in
the ?ash drum is maintained at a temperature of
about 190° F. and a pressure of about '75 pounds
per square inch absolute. The portion of sulphur
dioxide evaporated in the drum H0 is passed
through conduit I I I to the heat exchanger or con
denser I I2, where it is cooled to about 93° F., and
thence to the S02-separator H3.
The sulphur
dioxide in separator H3 is maintained at a tem
perature of about 93° F. and a pressure of about
75 pounds per square inch absolute. The con
densed sulphur dioxide and gases removed from
the bottom of the separator I I3 are passed to the
exchanger or cooler I I4 and thence to the liquid
S02 manifold 53. Water or other suitable ?uids
may be used in the condenser H4 to cool the
liquid sulphur dioxide to about atmospheric
temperature. The uncondensed sulphur dioxide
and gases in separator I I3 are removed from the
top part thereof through conduit II5 to the
pressure reducing valve H6 and thence to the
40 S02-gas manifold 55 where they are returned
to the absorber I6 and re-used. The pressure
reducing valve II6 releases the gases into the
manifold at about the pressure of the gases enter
ing the lower part of the absorber I6.
The ra?‘inate, containing some dissolved sul
phur dioxide, is passed from the bottom of ?ash
drum IIO by conduit II‘! to the pressure reducing
valve II8, where the pressure is reduced to at
mospheric pressure, and thence into the upper
part of the ra?inate stripper II9, where the
ra?inate is permitted to descend over the baffle
plates, bubble plates, or packing material I20,
disposed therein. Ra?lnate in the lower part of
the tower is removed from the trapout plate I2I
by conduit I22 and passed through the heater or
heat exchanger I23 where the raf?nate is heated
to about 260° F.
Live steam or the like may be
passed through conduit I24 as a heating medium.
The heated raf?nate is returned by conduit I25
60 to the bottom part of the stripper where it
materially aids in removing the dissolved sulphur
dioxide from the raf?nate.
The stripped or va
porized sulphur dioxide with a small amount of
ra?inate vapors, are removed from the top of the
rai?nate stripper II9 through conduit I26 to the
condenser I21 Where the ra?lnate vapors are
condensed and returned by the conduit I28 to
the top part of the raf?nate stripper. The con
densed materials returning to conduit I28 are
usually at a temperature of 120° F. and pressure
maintained in the upper part of the ra?inate
stripper H9 is about 7 to 8 lbs. per sq. in. abso
lute. Any suitable cooling ?uid, such as water,
may be passed through conduit I 36 to produce the
desired cooling e?ect in the condenser I27. The
uncondensed materials and S02 gas pass from the
condenser I 21 by the conduit I3I to the mani
fold I02 and returned to a compressor unit
which will be described hereinafter.
The stripped railinate is passed from the bot
tom of the stripper H9 by the conduit I32 to the
pump I33 and forced through conduit I34 and
heat exchanger I09 to the washer I35 where the
raf‘?nate is washed with an alkaline reagent such
as an aqueous sodium hydroxide solution to re
10
move the last traces of sulphur dioxide. Any
convenient tower or washing means may be used
to remove the last traces of sulphur dioxide from
the raf?nate. The washed ra?inate is then
passed by conduit I36 to the ra?inate storage
tank I 37. This rai?nate may be recracked at
high temperature and the product again ex
tracted by passing it to the bottom of the ab
sorber I6.
The S02 gas, containing some hydrocarbon 20
materials and compounds, removed from the ex
tract stripper 93 and railinate stripper H9, is
passed through conduit I02 to the gas booster I38
where it is forced through the conduit I39 to the
separator drum I40. The pressure in conduit 25
I 02 is usually about '7 to 8 pounds per square inch.
The ?ashed S02 gas from the chiller 36 is also
passed to the separator drum I40 by the conduit
MI. The pressure maintained in the separator
drum I40 is the same as the pressure maintained
in the top part of the chiller 36; that is, about
11 to 12 pounds per square inch absolute.
The
entrained liquids and condensed naphthas settle
to the bottom of the separator drum I40 and are
withdrawn through the valved conduit I42. The '
S02 gas passes from the top of the separator drum
I40 through conduit I43 to the bottom part of
the drier I 44. Solid drying agents such as cal
cium chloride or sodium sulphate may be used
to dry the S02 gases, similarly, strong sulphuric 40
acid may be passed countercurrently to the
stream of S02 gases in order to dry the same.
The dry S02 gas is passed by the conduit I45 to
the compressor I46 where it is compressed to a
pressure of about '70 pounds per square inch ab
solute. The compressed gases are then cooled by
the condenser I41 and passed to the S02 sepa
rator I48. The liquid sulphur dioxide is passed
from the bottom of the separator I48 by conduit
I49 and returned to the liquid-S02 manifold 53.
The uncondensed gas passes from the top of the
separator I48 through the pressure reducing valve
I50 where the pressure is reduced to about 19 to
20 lbs. per sq. inch absolute, and thence through
the conduit 56 to the bottom part of the ab
sorber I6.
In the operation of our extraction process it
will be observed that the sulphur dioxide is re
covered from the extract and ra?‘inate by three
di?erent methods. In the SOz-separators 5|, 63,
‘I4, 81, H3, and I48, the gaseous sulphur dioxide
is recycled by the S02-gas manifold 56 to the
bottom of the absorber I6 and reabsorbed in the
hydrocarbon naphtha to be extracted and con
sequently recompression of the S02 gases before
reusing the same is avoided. The liquid S02 re
covered in the above six S02 separators is re
turned to the liquid-S02 storage tank 32 and then
returned to the extractor 3I (after passing
through chilling tower 36) where it is used in the 70
extraction of the naphtha. The gaseous sulphur
dioxide recovered from the extract stripper 93,
ra?inate stripper II9, chilling tower 36 and heat
exchanger 30 are compressed by the compressor
I46, lique?ed and returned to the storage tank 32 75
2,071,590
and then reused in the extractor 3i. By our
vherein described process a substantial portion of
the S02 used to extract the naphtha is recovered
and reused to extract fresh naphtha without be
ing recompressed or recondensed. After our proc
ess has once made a complete cycle of operation,
the lost sulphur dioxide is replaced by the S02
gases from the sulphur burners or acid plant
which enter the conduit i8.
2. In theprocess of separating petroleum naph
thas containing detonating and anti~detonating
constituents into fractions respectively which are
more detonating and more anti-detonating than
the original naphthas, the steps comprising simul
taneously extracting a heavy naphtha and a
lighter naphtha, continuously passing the light
naphtha coiuitercurrent to and in contact with
It should be understood that the temperatures,
pressures, and conditions of operation will vary
10
gaseous sulphur dioxide and nitrogen in a ver
tical elongated contact zone, continuously adding
a small amount of the heavier naphtha near the
somewhat with the manner and mode of oper
ating the plant and that the use of different tem
peratures, pressures, etc. do not depart from the
~15 scope of our invention. The particular charac
teristics of the naphtha to be extracted will some
what determine the pressure and temperature
conditions to be used.
In the SOz-separators 51, 63, ‘M, 81, H3, and
top part of said contact zone to recover vapors
of the light naphtha, continuously removing the
combined naphtha solution of sulphur dioxide
from the lower part of the contact zone, passing 15
the said solution countercurrent to and in con
tact with liquid sulphur dioxide in a second con
tact zone, and separating the sulphur dioxide ex
tract from the remainder of the naphtha solution.
M8, the conventional type of ?oat valve may be
120 disposed
therein to maintain a predetermined
amount of liquid sulphur dioxide in the separa
tors. Generally the liquid level in these separa
tors is from 1/; to 1/2 full.
The amount of sulphur dioxide used in our
,25
process may vary with the type of naphtha ex
tracted, temperatures used and other operating
30
conditions. As one example or" our process, 370
barrels of cracked naphtha of 50° A. P. I. may
be put through the process in one hour and 1'78
barrels of extract and 192 barrels of raf?nate ob
tained.
In this example, about 560 pounds of
S02 gas are absorbed in the absorber l6 and
373,000 pounds of liquid sulphur dioxide are used
in the extractor 3|. Also, about 96% of the sul
phur dioxide used is recovered in the liquid phase,
without any recompressing, from the separators
5|, 53, 14, 81, H3, and M3; about 0.05% of the
sulphur dioxide is recovered as a gas and reab
sorbed in the absorber l6; and about 4% of the
sulphur dioxide (exclusive of that used in ex
changer 3?! to cool the naphtha and of that evap~
orated to take care of heat losses) is recovered
as a gas and lique?ed by the compressor unit.
Not more than 0.1% of the sulphur dioxide en
45
tering the system is lost.
While we have described our process with refer
ence to specific temperatures, pressures, volumes
and operating conditions, it should be understood
50 that our invention is not restricted by such limi
tations. The above conditions of operation may
be altered by those skilled in the art without de
parting from the scope of the invention as set
55
5
forth in the claims and speci?cation.
We claim:
1. In the continuous process of separating pe~
troleum naphtha containing detonating and anti
detonating constituents into fractions respective
ly which are more detonating and more anti
detonating than the original naphtha, the steps
comprising dissolving gaseous sulphur dioxide in
said naphtha by countercurrently contacting said
naphtha with gaseous sulphur dioxide, cooling
said naphtha solution, extracting said naphtha
65 solution with liquid sulphur dioxide, separating
most of the sulphur dioxide from the sulphur cli~
oxide extract by multiple-stage evaporation
wherein the temperature and pressure in each
successive stage are progressively increased, cool
70 ing the vaporized sulphur dioxide to effect con
densation of a part thereof, separating the con
densed sulphur dioxide from the uncondensed
sulphur dioxide and recycling both the condensed
and uncondensed sulphur dioxide to aid in the
75 further extraction of the petroleum naphtha.
3. In the process of separating petroleum naph 20
tha containing detonating and anti-detonating
constituents into fractions respectively which are
more detonating and more anti-detonating than
the original naphtha, the steps ‘comprising con
tinuously passing the naphtha countercurrent t0 25
and in contact with gaseous sulphur dioxide in a
vertical elongated contact zone, adding a small
amount of a heavier naphtha near the top part
of said contact zone, removing the naphtha solu
tion of sulphur dioxide from the lower part of the 30
contact zone, cooling said naphtha solution of
sulphur dioxide to a temperature within the range
of 5 to —-10° F., passing said cold naphtha solution
of sulphur dioxide countercurrent to and in con—
tact with liquid sulphur dioxide at a temperature
within the range of 5 to —~10° F. in a second con—
tact zone, separating the sulphur dioxide-extract
from the remainder of the naphtha solution, and
then separating substantially all of the sulphur
dioxide from the extract by multiple-stage evapo
ration wherein the temperature and pressure in
each successive stage are progressively increased.
ii. In the process of separating petroleum naph
thas containing detonating and anti-detonating
constituents into fractions respectively which are 45
more detonating and more anti-detonating than
the original naphthas, the steps comprising simul—
taneously extracting a heavy naphtha and a
lighter naphtha, continuously passing the light
naphtha countercurrent to and in contact with a 50
mixture of gases containing sulphur dioxide and
nitrogen in a vertical elongated contact zone, add
ing a small amount of the heavier naphtha near
the top part of said elongated contact zone to
recover vapors of the lighter naphtha, continu 55
ously removing the naphtha combined solution
of sulphur dioxide from the lower part of the con
tact zone, cooling said naphtha solution, passing
said naphtha solution countercurrent to and in
contact with liquid sulphur dioxide at a tempera 60
ture within the range of 10 to —60° F. in a second
contact zone, and separating the sulphur dioxide
extract from the remainder of the naphtha solu
tion.
5. In the process of separating petroleum naph 65
tha containing detonating and anti-detonating
constituents into fractions respectively which are
more detonating and more anti-detonating than
the original naphtha, the steps comprising dis
solving gaseous sulphur dioxide in said naphtha 70
by countercurrently contacting said naphtha with
gaseous sulphu~ dioxide, cooling said naphtha so
lution, extracting said naphtha solution with liq
uid sulphur dioxide at a temperature within the’
range of 5 to —10° F., separating most of the sul 75
6
2,071,590
phur dioxide from the sulphur dioxide-extract by
multiple-stage evaporation wherein the tempera
ture and pressure in each successive stage are pro
gressively increased, and then separating the re
mainder of the sulphur dioxide from the extract
by ?ashing and heating the same.
6. In the continuous process of separating pe
troleum naphtha containing detonating and anti
detonating constituents into fractions respectively
10 which are more detonating and more anti-deto
nating than the original naphtha, the steps com
prising passing the naphtha countercurrent to
and in contact with gaseous sulphur dioxide in a
vertical elongated contact zone, adding a small
15 amount of heavier naphtha near the top part of
said elongated contact zone, continuously remov~
ing the naphtha solution of sulphur dioxide from
the lower part of the contact zone, cooling said
naphtha solution, passing said naphtha solution
20 countercurrent to and in contact with liquid sul
phur dioxide at a temperature within the range
of 10 to —60° F. in a second contact zone, sepa
25
rating the SOz-extract from the remainder of the
naphtha solution, separating most of the sulphur
dioxide from the SOz-extract by multiple-stage
evaporation wherein the temperature and pres
sure in each successive stage are progressively
increased, cooling the vaporized sulphur dioxide
to e?ect condensation of a part of the same, sepa
rating the liquid sulphur dioxide from the sulphur
dioxide vapors, recycling the sulphur dioxide va
pors to the vertical elongated contact zone, and
recycling the liquid sulphur dioxide to the second
contact zone.
7. In the continuous process of separating pe
toleum naphtha containing detonating and anti
detonating constituents into fractions respectively
which are more detonating and more anti-deto
nating than the original naphtha, the steps com
prising passing the naphtha countercurrent to
and in contact with gaseous sulphur dioxide in a
vertical elongated contact zone, adding a small
amount of heavier naphtha near the top part of
said elongated contact zone, continuously remov 10
ing the naphtha solution of sulphur dioxide from
the lower part of the contact zone, cooling said
naphtha solution, passing said naphtha solution
countercurrent to and in contact with liquid sul
phur dioxide at a temperature within the range 15
of 10 to —60° F. in a second contact zone, separat
ing the SO2-extract from the remainder of the
naphtha solution, separating most of the sulphur
dioxide from the sulphur dioxide-extract by mul
tiple-stage evaporation wherein the temperature 20
and pressure in each successive stage are pro
gressively increased, 'cooling the vaporized sulphur
dioxide to effect condensation of a part of the
same, said cooling being accomplished at least in
part by indirect heat exchange between the va
porized sulphur dioxide from one stage and the
liquid material passing to the next preceding
stage, separating the liquid sulphur dioxide from
the sulphur dioxide vapors, recycling the sulphur
dioxide vapors to the vertical elongated contact 30
zone, and recycling the liquid sulphur dioxide to
the second contact zone.
ERNEST W. THIELE.
FRED W. SCHEINEMAN.
35
Документ
Категория
Без категории
Просмотров
1
Размер файла
1 059 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа