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Патент USA US2117457

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May 17, 1938.
H. C. SCHUTT
METHOD OF CONVERTING HYDROCARBONS
Filed Oct. 24, 1955
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Patented May 17, 1938 l
, 2,117,457
UNITED STATES `PATENT ori-‘ICE
METHOD 0F CONVERTING HYDROCARBONS
Hermann Claus Schutt,- North Tarrytown, N. Y.,
assigner, by mcsne assignments, to The Pure
Oil Company, Chicago, lll., a corporation of
Ohio
Application October 24, 1935, Serial No. 46,542
11 Claims.
My invention relates to a process and apparatus
aromatic products therefrom, separatingthe liq
under suitable conditions of temperature and
uid products from the lower boiling hydrocarbons,
recycling the lower boiling hydrocarbons to the
pressure, to convert the same into polymers, in
Ui
cluding aromatic and other cyclic compounds
such as naphthenes, having valuable anti-detona
tion 'characteristics and suitable for use as motor
fuel.
1
the production of the maximum yield of desired _
for cracking and polymerizing hydrocarbons,
'
It is a primary object of my invention to pro
vide a process in which low-boiling hydrocarbons
such as occur in petroleum reiinery gas, particu
larly gases containing a considerable amount of
unsaturates such as gases from liquid phase,
liquid-vapor or vapor phase cracking still opera--v
tions, may be converted into heavier hydrocar
bons of the aromatic series, under conditions
which will result in a high yield of high octane
aromatic-containing liquid boiling within the
range of the nature of gasoline motor fuel, and
20 minimize the formation of undesirable products
such as tar and fixed gases, e. g., methane and
ethane.
‘
In general, my process comprises the separa
tion of the mixture to be used as charging stock,
25 as for example, a. gas containing aliphatic Cz, Ca
and C4 hydrocarbon compounds preferably com
prising in excess of thirty per cent unsaturates,
into fractions respectively more diiiìcultly poly
merizable in accordance with the increased mo
30 lecular Weight of the unsaturates in successive
initial separating step and removing stabilized 5
aromatic-containing products of the nature oi
motor fuel from the system.
Y
In accordance with my invention, I may pass
the lighter compounds, as for example, the Cz
hydrocarbons of the starting mixture directly to 10
the intermediate cracking step when these form
a relatively small percentage of the starting mix
ture, to convert the C2 saturates to unsaturates»
for polymerization in the subsequent low pressure
polymerization stage. On the other hand, when
the percentage of lighter C2 unsaturates in the
starting mixture is relatively high, it may be pref
erable to pass these directly to the low pressure
polymerization stage for the production of a
20
maximum yield of desired aromatic products.
I have found that the operating conditions most
suitable for eii'ecting polymerization of heavier
unsaturates undergoing treatment, e. g., butylene,
are not suitable for the polymerization of ethylene
since the latter will polymerize much more rap 25
idly under the same temperature-pressure con
ditions. \ Hence, I have found it desirable to sepa
rate the hydrocarbons according 'to boiling point
as a measure of reaction velocity and subject
them to separate stages ofl polymerization and
fractions, subjecting the most diñicultly poly
most favorable to the velocity constant, or reac
merizable fraction, as for example, that contain
ing substantially C3 and C4 unsaturated com
tion velocity, of each.
I have also found that during the polymeriza
tion of the C3 and C4 compounds, a part of the
pounds, to high temperature, high pressure poly
35 merization conditions most favorable to the pro
duction of the maximum yield of desired aromatic
hydrocarbons which may be obtained from that
particular fraction, separating the aromatic
products from the unreacted low boiling hydro
40 carbons, subjecting the unreacted hydrocarbons,
as for example, the saturated Cs and C4 com
pounds, to high temperature, low pressure crack
` ing conditions most favorable to the maximum
yield of lighten, more easily polymerizable com
45 pounds, as for example, substantially Cz unsatu
saturates present are converted to lighter un
more easily polymerizable compounds as a frac
this light fraction to high temperature, low pres
- 50 sure polymerization `conditions most favorable to
35
saturates. The complete conversion of these
saturates to C2 unsaturates is best carried out,
however, by a subsequent cracking of all or a
part of the polymerization reaction products from
which the aromatic and other higher boiling 40
products formed during the initial polymerization
stage have been substantially removed.
The
endothermic character of the cracking reaction
is such as to permit cracking of the C2, Ca and
C4 compounds as a 'group at an average tempera
rated hydrocarbons, separating these lighter, - ture without excessive decomposition of the heav
tion from the liquid products formed, subjecting
30
ier C4 compounds to coke or tar.« I jdo not, there
fore, deem it essential that the separation of
the C2, Ca and C4 saturates into their respective
fractions and cracking of each separately be
45
2
2,117,457
practiced though such operation would more
nearly approach ideal conditions for optimum
conversion of the saturates to unsaturates.
’Assuming the charging gasto have the follow
ing composition, I cool the gas under pressure
to substantially separate the C3-C4 compounds as
a liquid from the C2 compounds and methane as
. follows:
Table
10
low pressure polymerization stage may be passed 10
Mol. per MOL per
uoâäid
cent gas
5. s
1. 7
57. 8
n. 2
1l. 7
38. 4
14. ñ
24. 2
4. 5
19. 0
.8
8. 8
20
to the low pressure, high temperature polymeri
zation coil. Where the gases remaining un
condensed after llquefaction of thev feed for the
first polymerizing coil contain a relatively high
percentage of C2 unsaturates, I prefer to charge
these gases directly to the low pressure, high tem
perature polymerization coil rather than to the
gas cracking coil as previously described.
The gaseous chargeto the heating coil of the
im. 0
1. 5
_
thereinto at a pressure of from 150 lbs./sq. in.
gauge to 300 lbs/sq. in.‘gauge, preferably at
about 225 iba/sq. in. gauge and rapidly brought
up to a temperature sufllcient to initiate the
polymerization reaction a'fter which it passes to
15
a reaction coil of greater cross-sectional „area
than the heating coil, controlled as to tempera
ture.- The exothermic polymerization reaction is
permitted to go on in the reaction coil which
100. 0 . may be maintained at a mean pressure ranging 20
'I'he liquid fraction containing the Ca--Ci com
pounds is pumped directly to a heating coil where
it is brought up to a temperature sufficient to
initiate the exothermic polymerization reaction
after'which it is passed to a high pressure, high
from 15 lbs./sq. in.- gauge to 120 lbs/sq. in. gauge,
preferably about 80 -lbs/sq. in. gauge, and at a
mean temperature ranging from l100° F. to
1300“ F., preferably about 1200" F. Following
the proper 'time interval for polymerization, the 25
reaction products may then be quenched to a
temperature reaction coil, preferably of larger temperature below approximately 600° F., pref
cross-sectional area than the heating coil, con
trolled as to temperature, where the polymeriza
30 tion reaction is permitted to take place. - The
reaction coil may be operated at a mean tempera
erably about 325° F. to inhibit'further polymeriza
tion. 'I'he products, following the removal of tar
and fuel oil formed during the polymerization 30
reaction, is subjected preferably to steps of ab
ture range of from 1050° F. to 1150“ F., prefer
sorption and rectiñcation for the recovery of un- ì
ably at about 1080 F. and at a mean pressure
stabilized aromatic-containing liquid free of ñxed
gases such as hydrogen and methane which lat
range of 200 lbs/sq. in. gauge to 400 lbs/sq. in.
35 gauge, preferably at about 300 lbs/sq. in. gauge.
'I'he polymerization reaction products withdrawn
from the .reaction coil may be quenched to a
temperature below approximately 600° F. and
preferably about 425° F.. to inhibit the polymeri
zation reaction, the products after fuel oil and
tarseparation being cooled and fractionated to
ter are vented as residue gas.
35
These unstabilized aromatic containing prod
ucts together with those recovered by compression
and cooling of the reaction products from the
cracking reaction are fractionated at high pres
sure for the recovery of the stabilized aromatic 40
containing products of the nature of .motor fuel.
recover aromatic and other liquid products aThe overhead products of the fractionating op
eration will consist mainly of a mixture of Ca-Ci
formed by the polymerization reaction.
The low boiling compounds such as the Cs--C4 compoundsl containing from forty per cent to
saturates remaining uncondensed are passed to a eighty per cent unsaturates and may be con
low pressure, high temperature gas cracking coil densed under pressure and recycled for subse
quent polymerization in the high pressure poly
primarily for conversion of saturates 'to Cz'un
'
saturates. 'I'he cracking reaction may be carried merization coil.
The tar and fuel oil separated from the re
out in the heating coil at a temperature range '
50 of from 1325o F. to 1600° F., preferably about , action products of each of the polymerization and
1375° F., and at a pressure range of from 25 cracking operations contain considerable light
distillate recoverable by stripping at pressures
lbs/sq. in. gauge to 125 lbs./sq. in. gauge, prefer
ably about '15 lbs./sq. in. gauge. The charge to ranging from 10 lbs./s`q. in. gauge. This liquid is
45
the gas cracking coil, though primarily consist
ing of the gases remaining uncondensed after sep
aration of the aromatic-containing products
formed by the polymerization operation,'may be
supplemented by the addition thereto of the un
condensed C2 gases of the initial separating oper
60 ation and the gases separated during the cooling
of the polymerization products for theA removal
55
of tar and fuel oil formed. p Obviously, therewill
be some polymerization of the unsaturates pres
ent and- formed during the`gas cracking operation.
These unsaturates, as”for example, the C2 com
pounds, will form desired aromatic products. 'I'he
reaction products withdrawn from the heating
coil may be quenched to below active cracking
temperature, i. e., to a temperature ranging below
70 approximately 600 F., preferably about 250° F.
The tar and fuel oil formed is then separated _from
the gaseous constituents which are compressed
and cooled to condense the desired aromatic prod
ucts present. 'I'he gases remaining uncondensed
75 contain the Ca unsaturates and form the charge
used as a quench medium supplementing that re
covered by cooling and condensation of a portion 55
of the quenched reaction products at higher pres
sures.
y
'It is to be understood that’ the temperatures
maintained in the respective reaction coils may be
varied according lto the type and amount of hy 60
drocarbons introduced, the pressure under which
the respective polymerization and reaction coils
may be operated, and the time of exposure of the
gases to the operating temperature. In case an
extremely high octane number is not desired, the 65
polymerization operations may be conducted at
pressures of the order of 400 lbs./sq. in. gauge to
3000 lbs/sq. in. gauge with correspondingly
lowerpolymerization temperatures ranging up
ward from 700° F.
-
The accompanying drawing which forms part
of this speciñcation and is to be read in con
Junction therewith, is a schematic showing of
apparatus in accordance withmy invention. ’
Refinery or pressure still gas may be intro
70
2,111,457
3
-is formed. 'I'his liquid, or polymer gasoline.
duced into the system through pipe I at a pres
passes from the reboiler 34 through pipe 35, heat
sure of from 250 to 350 lbs/sq. in. gauge, prefer
ably about 300 lbs./sq. in. gauge, partially lique
exchanger 3l, pipe 35, and cooler 31 into pipe 38
fied in the condenser 2 and passed into a feed having pressure control valve 39. The polymer
tank 3. Assuming the gas charged to comprise - gasoline in pipe 38. is combined with other
mainly Cz, C: and C4 hydrocarbons, the hydrogen polymer gasoline formed as will be hereinafter
present, methane and mainly Cz hydrocarbons shown, to produce a motor fuel of high blending
may be withdrawn from the tank through the
pipe 4 and passed into the light gas feed pipe 5.
-The overhead products of the fractionator 33
'I'he direction of gas flow in this pipe may be will consist of ca_-C4 saturated compounds which 10
selected by suitable manipulation of the pressure pass through the condenser 45, pipe 4I and into
value.
control valves 6, 'l and 8 as will be more fully ex
plained hereinafter.
‘
'I'he liquefleld Ca and C4 hydrocarbons in the
15 tankl I may be withdrawn therefrom through
the pipe 9 and charged by the pump I0 through
the pipe Ilgat a pressure of about 400 lbs/sq. in.
gauge to the heating «coil I2 of the high pressure
polymerization stage where the re‘actant in pass
20
y the reflux accumulator 42.
i
l
Condensate is with
drawn through the pipe 43 by means of the pump
44 and returned thereby through pipe 45 to the
primary fractionator as reflux.
15
Uncondensed Cri-_C4 gases may be vented at the
accumulator pressure through pipe 45 andl pres
sure control valve 41 into the heating coil 48 of
thel gas cracking unit. The charge to the gas
ing through the coil is brought up to the desired - cracking coil may be supplemented by the C2 20
gases in pipe 5 which flow therefrom through
polymerization temperature. The reactant dis
charges from the heating coil I2 into the reaction pipe 43 and pressure reducing valve 50 into pipe
coil I3 Where a mean temperature of about l080° 46. Valve 8 in line 5 may be partially or entirely
F. and a mean pressure of about 300 lbs/sq. in.
gauge may be maintained. The time allowed for
passage of the reactant through the coil I3 is
sufficient to effect maximum conversion of the
Cs-C4 unsaturates to higher boiling aromatic
products. On leaving the reaction coil, the re
30 action products are immediately contacted in the
arrester I4 with a cool -light quench distillate
entering the arrester through the pipe I5 and
suddenly cooled to a temperature of about 425°
F. to inhibit further polymerization, the quenched
products passing from the arrester into a tar
separator I5.
'I'he fuel oil and tar separator I5 functions to
remove such heavy polymers from the reaction
products as are formed during the polymeriza
40 tion reaction, the tar and fuel oil being dis
charged under the existing pressure through the
pipe I1 into the feed pipe I 9 by which the tar
is conveyed to a subsequent stripping operation.
A valve I8 in the pipe I1 controls the passage of
45 tar into the pipe I9. Bubble plates or other suit
able fractionating trays (not shown) and internal
reiiuxing in the separator 'ensure sharp separa
tion of the tarry products and the lower boiling
hydrocarbons. The uncondensed hydrocarbons
50 may be withdrawn through the pipe 20, pass
through a condenser 2l and pipe 22 into the dis
tillate accumulator 23.
The distillate accumu-_
lator may be maintained at a pressure of from
215 lbs/sq. in. gauge to 325 lbs/sq. in. gauge,
closed.
’
The reactant in the gas cracking coil may be 25
preferably subjected to a temperature of about
1375° F. at a pressure of 'about 75 lbs./sq. in. gauge
so as to- form a maximum of C2 unsaturates as
Well as such aromatic-containing products of the
nature of motor fuel as result from the conversion 30
of C2 unsaturates during the cracking interval.
The reaction products discharged from the crack
ing coil are immediately quenched in arrester 5I
toabout 250° F. by cool light distillate from pipe
52, the quenched products passing through pipe
53 into fuel oil and tar separator 54.
`
The tar separator 54 may be »provided with
suitable fractionating trays (not shown) and by
_suitable reiiuxing, a separation of such heavy
tar and fuel oil as was formed bythe cracking 40
reaction from‘ the lower boiling hydrocarbons, is
eil'ected. The tar separated flows through pipe
55 and pressure reducing valve- 55 into feed line
I8 for subsequent stripping, `as will be more fully
described hereinafter.
.
'I‘he overhead products of the tar separator 54
pass through pipe 51, condenser 5,8 and pipe 59
into the quench accumulator 58. Due to pres
sure drop, the accumulator pressure will range
from 20 lbs./sq. in. gauge to 120 lbs/sq. in. gauge, 50
preferably about 65 lbs/sq. in. gauge with the re
sultant formation of but a small quantity of con-a
densate. I propose to supplement this conden
sate with quench distillate recovered from strip
ping of the tar as will be more fully described
hereinafter. Condensate is withdrawn from the
preferably about 275 1bs./sq. in. gauge. Gases
may be vented from the accumulator through
pipe 23’ and control valve 24 .into the light gas accumulator through pipe 8| by pump 62 which
feed pipe 5. 'I'he vented> gases will be largely Cz _ returns a portion through pipe 52 as quench dis~
hydrocarbons with some methane and hydrogen. tillate to arrester 5I. The remainder is fed
60
Condensate in the accumulator 23 may be with
through pipe 83 as reflux to the tar separator 54. co1
drawn through the pipe 25 and pipe 25 by means
Uncondensed low boiling hydrocarbons pass
of the. pumps 21 and 28. The pump 21 returns a
portion of its feed as quench distillate through> from the accumulator through the pipe 54 to com
pipe I5 to the arrester I4 and the remainder pressor 55 by which they may be compressed to
65 through pipe 29 to the tar separator as reñux. from 150 lbs/sq. in.- gauge to 350 lbs/sq. in. 65
The pump 28 forces its condensate feed through gauge, preferably about 250 1bs./sq. in. gauge,
pipe 30, heat exchanger 3i and pipe 32 to primary and then passed through pipe 88, condenser 61
and pipe 58 into distillate accumulator 59. At
fractionator 33.
the pressure in the accumulator 69 of from 1.50
'I‘he fractionator 33 may be operated at a pres
70 sure of from 250 lbs./sq. in». gauge to 350 lbs./sq. lbs/sq. in. gauge to 300 lbs/sq. in. gauge, pref 70
in. gauge and by means of bubble trays (not erably 225 lbs/sq. in. gauge, the uncondensed
low boiling hydrocarbons will be mainly Cz com
shown), refluxing and reboiling of the frac
tionatory bottoms in reboiler 34, a stabilized aro
pounds, primarily unsaturates formed by the
matic-containing liquid of the nature of motor
cracking reaction. 'I'he condensate will be aro
matics of the nature of motor fuel formed due to 75
75 fuel of 85 to 90 Octane No. CFR. Motor Method
4
2,117,457
such polymerization of C2 unsaturates asj took
place in the gas cracking coil 48.
pipe 84 vby pump 85 and passes through pipe 8,6,
heat exchanger 81,»pipe 88, preheater 89 and pipe
Gaseous C2 hydrocarbons pass from the accu
|00 into combined still and rectifier tower |0|.
mulator 68 through the pipe 10 into heating coil
The oil may enter the tower |0| at a pressure of
1| of the relatively low pressure polymerization
stage. When the percentage of C2 unsaturates
in the gases fed to the system through the pipe |
is -sufliciently high to render immediate poly
lmerization of _these gases feasible, valves 1 and 8
10 in pipe 5 are closed and valve 6 is opened so that
the C2 hydrocarbons withdrawn from the feed
tank 3 through the pipe 4 pass through pipe 5 and
are commingled with Vgases in pipe 18 passing to
from 250 lbs/sq. in. gauge to 450 lbsr/sq. in. gauge,
preferably about 325 lbs/sq. in. gauge, and at a
the heating coil 1|.
’
'
l
The reactant may be heated in coil 1| suili
temperature of from 450° F. to 650° F., preferably ,
about 525° F. The absorption oil is stripped with
steam entering the tower through pipe |02, the
steam condensate formed in the rectifying section 10
of the tower being withdrawn from collecting
trays (not shown) through pipe |03. Sharp
separation of the absorption oil from the ab
sorbed hydrocarbons is secured by suitable frac
_tionating trays (not shown) in the rectifying sec 15
ciently to initiate the polymerization reaction
tion of the tower in conjunction with cool reñux
and passes into reaction coil 12 where exothermic
polymerization may proceed at a mean tempera
entering the tower through the pipe |04. The
lean absorption oil is withdrawn through pipe |05
ture of about 1200° F. and a mean pressure` of
by means of pump |08 and is returned to the
about 80 lbs./sq. in. gauge. The reactant after
absorber 88 through pipe |01, heat exchanger 81, 20
a time interval suñicient to form the desired aro
pipe |08, cooler |08 and pipe 80.
matic-containing products discharges into ar
rester 13 wherein it is contacted with cool light
. distillate entering the arrester through pipe 14.
The_reaction/products are quenched in the ar
’
The overhead products of the tower |0| pass
through pipe H0, condenser ||| and pipe ||2
rester to a temperature of about 325° F. to inhibit
into separator ||3 where at a pressure of from
245 lbs/sq. in. gauge to 445 lbs./sq. in. gauge, 25
preferably about 320 lbs/sq. in. gauge and a
the polymerization reaction, the kquenched re
action products passing through pipe 15 into tar
about 80° F., a separation of some uncondensed
and fuel oil separator 16.
`
1
'
`
The tar separator 16 by means of suitable
fractionating trays (not shown) and cooling re
flux effects a separation of heavy tarry polymers
and fuel oil formed from the lower boiling hydro
carbons. The tar separated discharges through
pipe 11 and pressure reducing valve 18 into pipe
|8 for subsequent tar stripping, as will be more
fully described hereinafter.
The uncondensed overhead products of the tar
separator pass through pipe 18, condenser 80 and
40 pipe 8| into quench distillate accumulator 82
which may beA maintained under a pressure of
from 25 lbs./sq. in. gauge to 100 iba/sq. in. gauge,
preferably about 50 lbs/sq. in. gauge, and a tem
perature of from 100° F to 200° F., preferably
temperature of from 60° F. to 100° F., preferably
C2 hydrocarbons may be effected, these being
vented through pipe ||4, pressure control valve
||5, pipe ||6 and pipe 83 into the residue gas
pipe 5.
The separator liquid is partly reiiux and dis
charges from the separator ||3 through pipe I |1,
a portion passing through pipe ||8 to pump ||8
and being returned thereby through pipe |04 to
30
35
the tower |0| as reñux, the remaining net con
densate passing through pipe |20, pressure re
ducing valve |2| and pipe |22 into feed tank |23.
The liquid aromatic-containing products formed 40
during the gas cracking operation and collected
in the distillate accumulator 68, are also passed
under the pressure existing therein through pipe
|24 into‘pipe |22 to the feed tank |23. Any light
about 125° F. In the accumulator 82, a separa-v ' Cz hydrocarbons remaining in the liquid passing
to the feed tank |23 which hydrocarbons are to
carbons is made. 'I'he condensate is withdrawn be removed from the liquid may be vented Afrom _
tion of condensate from the uncondensed hydro-`
through pipe 83 by'pump 84 and returned there
by through pipe 14 to arrester 13 as quench dis
tillate and through pipe 85 to the separator 15 as
reflux. Excess condensate from accumulator 82
may be passed through valve-controlled line 86'
and joined with the condensate leaving distillate
accumulator 88. The uncondensed hydrocarbons
55 pass from the accumulator 82 through pipe 86,
' cooler 81 and pipe 88 into -absorber 88 of an
absorption unit.
'I'he gas feed may enter the absorber at a tem
peraturev of from 60° F. to 100° F., preferably
60 about 80° F., and at a pressure of from 25 lbs./sq.
in. gauge to 100 lbs/sq. in. gauge, preferably about
50 iba/sq. in. gauge, and passes through the
absorber countercurrent to downflowing lean
the accumulator through pipe |25, valve |26,
pipe ||5 and pipe 83 to the low pressure section
of residue gas pipe 5.
.
The liquid in the feed tank |23 contains the de
50
sired aromatic-containing products of the nature
of motor fuel formed-in the low pressure gas
cracking and polymerization stages and is with
drawn through the pipe |21 by pump |28 and 55
passed through pipe |28, heat exchanger |30 and
pipe |3| into secondary fractionator |32. 'I'he
fractionator |32 is a conventional stabilizer
which may be operated at from`2'l5 lbs./sq. in.
gauge to 475'lbs._/sq. in. gauge, preferably about 60
350 lbs./sq. in. gauge, and have suitable reboiling
means |33.- The bottoms discharged from the
reboiler |33 are aromatic-containing products of
absorption oil entering the absorber through pipe v the nature of motor fuel of 90 to 100 Octane No.
65 80. The aromatic and other normally liquid
CFR Motor Method stabilized as to end point
products of the nature of motor fuel together with and these, pass through pipe |34, heat exchanger 65
most of the Ca-Ci hydrocarbons which comprise
from forty per cent to eighty per cent unsatu
rates, are removed from the gases by the absorp
70 tion oil, the residual hydrogen, methane and some
C2 hydrocarbons passing ofi' through pipe 8|,
pressure reducing valve 82, and pipe 83 into -the
' residual- gas pipe 5, in which valve 8 may be
partially or entirely closed.
75
'
s
.
The rich absorption oil is withdrawn through
|30, pipe |35, cooler |36, pipe |31 and pressure
reducing valve |38 into pipe 38 wherein they are
blended with the stabilized aromatic products of
the high -pressure polymerization operation and 70
discharged from the system as the flnaiproduct.
'I‘he overhead products of the fractionator |32
are mostly C3-C4 hydrocarbon compounds which
pass` through pipe |38, condenser |40 (wherein
they are substantially completely condensed) and ' 75
5
2,117,457
pipe |4| into reflux accumulator |42. A portion
of the condensate is withdrawn from the accu
mulator |42 through pipe |43 by pump |44 and
returned through pipe |45 to the fractionator
|32 as reflux.
The net condensate in the ac
cumulator |42 ñows through the pipe |46 under
the existing pressure'back into the pipe I as re
cycle entering the system with the fresh gas.
The tar and fuel oil separated from the reac
10 tion products following each of the conversion
steps and discharged into the feed pipe |9, passes
tract the remaining heavier gas fractions and
light vapors therefrom. The unabsorbed gases
are eliminated through line 9|. The absorbed
constituents are eventually passed through line
|20 to join the distillate from the cracking stage
in line |20. The combined liquid fractions are
passed to accumulator |23 and from there to
fractionator |32. The gas from fractionator |32,
which was dissolved in and separated from the
liquid fractions, is recycled through line |46 to
tower |49 wherein at a reduced pressure of from
the high pressure polymerization coil |2.
While the foregoing description of my process
illustrates the treatment of the Ca-Ci unsat
10 lbs/sq. in. gauge to 50 lbs/sq. in. gauge, pref
urates in the high pressure,4 high temperature
through heater |41 and pipe |48`into stripping
15 erably about 25 lbs/sq. in. gauge, and by the
addition of heat, the fuel oil and tar may be
stripped of the lower boiling hydrocarbons and
passes from the stripping tower through the pipe
|50. cooler |5I, pipe |52 and pressure reducing
20 valve |53 to storage tanks (not shown). The
lower boiling hydrocarbons flow upwardly
through fractionating trays (not shown) counter
current to downñowing reflux. the overhead
products passing through pipe |54, condenser |55
25 and pipe |56 into accumulator |51.
The low
boiling quench condensate formed is withdrawn
from the accumulator through pipe |58 by pump
|59 which discharges through the pipe |60. A
portion of the distillate in the pipe |60 is re
30 turned through pipe IBI and pressure control
valve |62 to the tar stripper |49 as reflux.
'I’he net `discharge from the pipe |60 passes
10
polymerization coil and the treatment of the C2 15
unsaturates formed by cracking or by separation
from the gases entering the system, in a separate
high temperature, low. pressure polymerization
coil, it is to be understood that this is by. way
of example only. My process comprehends 20
broadly the treatment of the polymerizable nor
mally gaseous oleflnes lunder polymerizing con
ditions of heat and pressure which are in so far
as is commercially practical, establishedas most
favorable to the differing reaction velocities of 25
the respective hydrocarbons undergoing treat
ment.
`
It will be understood that certain features and
sub-combinations are of utility and may be em
ployed Without reference to other features and 30
sub-combinations. This is contemplated by and
is within the scope of my claims. It is further
obvious that various changes may be made in de
tails within the scope of my claims without de
through supply pipe |63 from which streams may
be returned through pipe |64 and pressure con
35 trol valve |65 to quench accumulator 60, through parting from the spirit of my invention. It is, 35
pipe |66 and pressure control valve |61 to dis therefore, to be understood that my invention is
tillate accumulator 23 and through pipe |69 and not to be limited to the speciñc details shown
pressure control valve |69 to quench accumulator and described.
82, respectively.
,
Having thus described the invention, what is
’
'
Although I have described my invention in claimed is:
40
40
1. The process for obtaining liquid aromatic
connection with the conversion of gases contain
hydrocarbons from normally gaseous olefin-con
ing a substantial proportion of oleñnic or un
saturated hydrocarbons, it will be understood taining hydrocarbons, which comprises separat
that natural hydrocarbon gases or refinery gases ing said gaseous hydrocarbons into fractions of
successively lower boiling range, separately heat
45 of low olefin content may also be treated sepa
rately or in conjunction with gases rich in ole -ing a fraction of higher boiling range to initiate
polymerization of the unsaturates present, in
fins. When the treatment of low oleñn contain
ing gases is contemplated, these gases may be
troducing the heated fraction to a reaction zone
fed into the pipe 46 leading to the cracking coil
48 in order to ñrst crack the gases. The resulting
wherein formation oi' polymers occurs, removing
the products of reaction from the reaction zone,
products may be treated in the same manner as
fractionally separating the Aproducts of reaction 50
into a tar fraction, an aromatic polymer frac
tion and unpolymerized hydrocarbons of suc
pointed out with respect to gases fed from pri
mary fractionator 33 and line 49.
When starting with predominantly saturated
gas, it is cracked in the coil 48, chilled at 5|, and
the tar separated from the reaction products in
unpolymerized hydrocarbons so separated to a
temperature at which said hydrocarbons will be
54.- ~The remaining'products pass through con- l
converted into unsaturated hydrocarbons, com- ~
denser 59 and accumulator 60 where part of the
bining gaseous reaction products from the last
mentioned conversion step with a ñrst mentioned
fraction of lower boiling range than the fraction
subjected to the aforesaid polymerization stepV 60
separately heating the combined gas fractions to
initiate polymerization of the unsaturates pres
reaction products are condensed and recycled as
cooling and reflux stock. The remaining uncon
densed vapors and gases pass through line 64
and compressor 65 and condenser 61 to accumu
lator 69. 'I'he heavier fractionsl of the gas, to
gether with the aromatic distillates, are con
65 densed and collected in 69. The Cz compounds,
which are not condensed, vare then charged
through heating coil 1| and reaction coil 12 for
polymerization. After separation of the tar from
the polymerized reaction products, the remain
ing products are cooled. The condensate is used
for chilling and reñux stock and any excess is
passed through line 86’ and joined with the con
densate from the cracking stage in line |24. The
gases from the polymerization stage are treated
75 with absorbent liquid -in tower 89 in order to ex
cessively lower boiling ranges, separately heating
ent, introducing the heated fractions last men- `
tioned to a separate reaction zone wherein for
mation of polymers occurs, removing the prod
65
ucts of reaction from said last mentioned zone,
and fractionally separating said last mentioned
products of reaction into a tar fraction,~ an aro
matic polymer fraction and normally gaseous hy
drocarbons.
»
70
-
2. The process of claim 1 including recycling
only the higher boiling portions of said last men
tioned normally gaseous hydrocarbons to said
ilrst mentioned heating step for further poly
merization.
-
`
.
6
2,117,457
Y
3. The process for obtainingliquid aromatic -reaction products into a heavy polymer fraction,
hydrocarbons from normally gaseous hydrocar
a fraction' containing the gasoline boiling range
bons, which comprises separating said gaseous constituents and a. gaseous' fraction, combining
hydrocarbons into liquid and gas fractions of the last mentioned gaseous fraction with one of
successively lower boiling range, separately heat
said ñrst mentioned fractions of lower boiling
ing said liquid fraction at high pressureto ini
tiate polymerization of the unsaturates present,
introducing the heated fraction to a reaction zone
wherein formation of polymers occurs, removing
10 the products of reaction from the reaction zone,
and quenching them to inhibit the polymeri
15
zation reaction, fractionally separating the
sure in a separate reaction zone suitable for
quenched products into a tar fraction, an aro
matic polymer fraction and unpolymerized gas,
polymeriz'mg unsaturated hydrocarbonsto aro
matic hydrocarbon liquids, said last mentioned
separately heating said unpolymerized gas and
temperature and pressure being respectively
a first mentioned gas fraction at a relatively low
pressure to a temperature at which said fractions
higher and iowen-than those to which said gas
eous hydrocarbon fraction is subjected _in the
will be converted to form polymers and substan
tial quantities of unsaturated hydrocarbons, re
20 moving the products of reaction from said last
mentioned heating zone, and quenching them to
inhibit the cracking- reaction, separating the
quenched products into a tar fraction, an -aro
matic polymer fraction anda gas fraction con
25
taining unsaturates, separately heating said last
mentioned gas fraction together with a nrst men
tioned gas fraction at a relatively low pressure
to initiate polymerization of the unsaturates pres
ent, introducing the heated fraction last men
'
gases are recirculated to the first mentioned con
version step.
.
9. 'I'he process for obtaining liquid hydrocar
bons from normally gaseous oleñn containing hy 25
drocarbons, which comprises separating said gas
eous hydrocarbons into a fraction Jcontaining
mation of polymers occurs, removing the prod
portion of said fraction to liquid hydrocarbons
polymerization reaction, fractionally separating
aromatic polymer fraction and unpolymerized
hydrocarbon fraction of successively lower boil
ing ranges.
`
4. The process of converting normally gaseous
hydrocarbons into low boiling liquid hydrocar
bons which comprises subjecting said gas to con
ditions of time, temperature, and pressure suit
able for converting saturated to unsaturated hy
drocarbons, separating the reaction products into
45 liquid and gaseous fractions, subjecting said gas
ization zone suitable for converting a substantial
boiling within the gasoline range, cooling the
reaction products, separating the normally liquid 35
from the normally gaseous constituents, subject
ing said normally gaseous constituents to condi
tions of temperature, pressure and time, in a
separate conversion zone, suitable for converting
a substantial portion of said gaseous constituents 40
to unsaturated hydrocarbons, separating the re
action products from said conversion- zone into
normally liquid and normally gaseous constitu
ents, mixing said last mentioned gaseous con
stituents with said fraction^containing chiefly 45
Cz and lower hydrocarbons, and subjecting the
eous fractions to high temperature and low pres
sure suitable for polymerizing unsaturated hy
drocarbons to liquids, separating> the reaction
mixture to polymerization in a separate zone at
products from the polymerization step into liq
than those to which said Ca, C4 fractions are
uid and gaseous fractions, combining liquid frac
tions from said conversion and said polymeriza
tion steps, separating dissolved gases from said
combined liquids, and polymerizing « separated
55 gases at higher pressure and lower temperature
vthan those to which said gaseous fractions are
subjected in the ñrst polymerization step.
5. Process in accordance with claim 4 in which
the second mentioned polymerization step is car
60 ried out at temperatures of 1050°--1080° F. and
the ñrst mentioned polymerization step is car
ried out at temperatures of 1100°-l200° F.
6. Method in accordance with claim 4 in which
the incondensible gases from the second men
65
»
8. Process in accordance with claim 7 in which
uncondensed gases from the polymerizing step 20
are eliminated from the system and liquefied
ucts of reactio'n from said last mentioned re
action zone and quenching them to inhibit the
35 the quenched products into a tar fraction, an
50
ñrst. mentioned conversion step. y
chiefly C3 and C4 hydrocarbons and another frac
tion containing chiefly C2 and lower hydrocar
bons, subjecting said Ca, C4 fraction to conditions 30
of temperature, pressure and time in a polymer
30 tioned to a separate reaction zone wherein for
'40
range, subjecting the combined fractions to con
ditions of time, temperature and pressure suit
able for converting saturated into unsaturated
hydrocarbons, separating liquid from gaseous re
action products, and subjecting the gaseous prod 10
ucts to conditions of time, temperature and pres
tioned polymerization step are eliminated from
the system.
.
‘7. 'I'he process for obtaining liquid aromatic
hydrocarbons from normally gaseous hydrocar
bons, which comprises separating said'gaseous
temperatures higher than and pressures lower
subjected.
‘10. Apparatus for converting hydrocarbon
gases to liquid hydrocarbons comprising means
for separating said gases into a higher boiling and
a lower boiling fraction, means for heating said
higher boiling fraction, reacting means for main 55
taining said heated gases under _conversion con
ditions for a period of time suiiìcient to convert
gaseous hydrocarbons to liquid hydrocarbons,v
means for separating reaction gases from liquids,
a second heating and reacting means, means for
charging said reaction gases to said second heat
ing and through said second reacting means,
means for separating liquid and gaseous reaction
products produced in said second reacting means,
a. third heating and reacting means, lmeans for 65
charging gaseous products produced in said sec
ond reacting means to said third heating and
through said third reacting means, and‘means
for optionally charging said lower boiling fraction
70 hydrocarbons into fractions of successively lower to said second-or said third heating means.
70
boiling range, separately heating one of said»
11. Apparatus for converting hydrocarbon
fractions of higher boiling range under conditions gases to lliquid hydrocarbons comprising means
0f time and pressuresuitable lfor converting gas
for heating and reacting said gases, means for
eous hydrocarbons into liquid hydrocarbons b_oil
passing said gases through said heating and re
75 4ing within .the _gasoline range, separating theV acting means, means `for separating gasœ from 75
7
the liquid reaction products, means for cracking
absorption medium, means for separating the
gases, means for passing said separated gases
absorbed 'constituents'irom the absorption me
dium, means for- mixing separated constituents
through said cracking means, means for separat
ing gases and liquids issuing from said cracking Vwith said condensible products, means for sepa- .
Ñmeans, a second'heating and reacting means.
means for charging gases from. said cracking
means to said second heating and reacting means.
means for separating condensible from incon-`
densible products issuing from said second react
ing means, means for absorbing the heavier por
tion of the incondensible products in a liquid
rating normally gaseous constituents from nor
mally liquid constituents rin said mixture, and
means for recycling separated normally gaseous
constituents to said first mentioned'heating and
reacting means.
HERMANN CLAUS SCHU'IT.
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