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Патент USA US2134702

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Nov. 1, 1938.
QT C_:BREWS_TER
2,134,702
‘SEPARATION :OF HYDROCARBONS
Filed Sept. 29, 1956
74/1. 645
24
i
r29
574545
645OL/1VE
INVENTOR
BY
W
_
ATTORNEYS
,
Patented Nov. 1, 1938
2,134,102 .
UNITED STATES PATENT OFFICE
2,134,702
,
SEPARATION or nrnnocalmons
Oswald C. Brewster, Litch?eld, Conn.,. _ assignor
to Re?nery Engineers Inc., New York, N. Y.,
a corporation‘ of Missouri
'
Application September 29, 1936, Serial No. 103,124
20 Claims. (Cl. 62-17515)
This invention relates to the recovery of lique
?able components from. hydrocarbon gas and are that the vapor mixture is cooled prior to its
expansion
more particularly to an improved method where
in the process and the-liquid condensate formed
furnishes-the refrigerant
used in one part of the
'
process.
In a copending application, Serial Number
10 103,121
?led September 29, 1936, a novel meth
; that the vapors evolved from the 10
15
' that a part of such heat ab- 15
20
20
25'
' that the compressed refrigerant 25
30
refrigerant to make up for losses or to provide 30
continuously .or in- 35
40
of the cooling‘ water available under the com- 40
50
ing; and that‘ fractionation of the refrigerant, at
both its high-boiling and
_
be continuously and automatlcally maintained
to the end that said pressure and temperature 55
2,134,702
2
requirements are met in the treatment of vapors
. of varying quality from a single field or from dif
2|! to the compressor end 2| of engine II which
is driven by the expanding dry gas as already de
scribed. The vapor is compressed to a relatively
ferent fields. Thus, apparatus for the practice
of this invention being transportable, the appa
high pressure slightly greater than that existing
in accumulator drum i5 to allow for frictional
aratus may be readily moved into any field and
it will automatically select and maintain a re
losses. The vapor, on being compressed, is heated
as usual when gases are compressed and dis
charges from compressor 2| into pipe 22 through
frigerant correctly suited to the pressure and
temperature conditions available in the appa
which it passes to reboiler coil 23 located so as to
described and is not limited to the simultaneous
furnish the required heat for condensate stabilizer
24. The hot compressed vapor in passing through
coil 23 is cooled and may be partially condensed
therein and passes through pipe 25 to condenser
use of all or of any particular number of such
26 in which it is further cooled and condensed by
ratus and ?eld.
_
‘This invention resides in the separate or con
10 joint use of the several features thereof herein
any suitable cooling medium, such as water or
features.
_
The operation of the invention will be fully un»
derstood from the following description taken in
connection with-the accompanying drawing, the
single ?gure of which represents diagrammati
cally apparatus for the practice of a preferred
embodiment of the invention.
air. The cooled refrigerant passes through pipe
21 to accumulator l5. Any uncondensed lighter
portion is vented through valve controlled pipe
28 to any suitable disposal system. This uncon
densed portion may be returned to the feed gas
‘
tail gas or otherwise
- Referring to the drawing, wet hydrocarbon gas
. Any unvaporized refrigerant
under substantial pressure enters the system
collected in separator l9 may be withdrawn by
pump 30 and discharged through pipe 29 to sta
and passes through heat ex
changer 2 in which'it is partially cooled by in
direct heat exchange with cold dry gas. From
.through pipe . |
exchanger 2 the feed gas passes through pipe 3
to heat exchanger 4 in which it is further cooled
bilizer 24 as shown or may be otherwise disposed
of according to its physical characteristics. The
amount of heat delivered to coil 23 is regulated
by by-passing controlled amounts of the hot com
by indirect contact-with a vaporizing refrigerant
as will be more fully described. The feed then
asses through pipe 5 to exchanger 6 in which
301)it is still further chilled by heat exchange with
pressed vapor around coil 23 by means of valve 30
controlled by-pass pipe 3|.
The refrigerant used in this auxiliary system
is derived directly from the condensate formed
cold dry gas. The cooling suffered by the feed and is secured in the following manner. When a
gas results in the condensation of practically all plant operating in accordance with the invention 35
of the desired higher boiling constituents of the is starting up for the ?rst time, no refrigerant is
available for the auxiliary system. However.
gas, along with a certain quantity of lower boil
35 ing material, not desired, forming a “wild" con
enough refrigeration is available from the cold
densate. The unlique?ed gas and the condensate expanded dry gas in exchangers 2 and 6 that a
pass through pipe 1 to separator 3 in which gas certain amount of condensate is formed and col
40
and condensate are separated. from separator lected in separator 8 even though exchanger 4 is
idle. This condensate, or va portion of it, is drawn
The unlique?ed dry gas passes
40 8 through pipe 9 to the inlet of power cylinder II through pipe 32 and released into the refrig
of engine H. The gas expands polytropically in erant coil of exchanger 4. The release in pres
engine ll, its energy being converted into work, sure and the fact that the feed gas passing
and the gas itself being cooled by the expansion through exchanger 4 is warmer than the con
according to well known thermodynamic prin
densate from separator-8 both cause vaporization
45 ciples. The cooled expanded gas exhausts from of the condensate ?ashed into the coil of ex
the engine into pipe l2 through which it passes changer 4, resulting in some refrigerating effect.
to heat exchanger 3 in which the gas chills the The partially vaporized material passes to sepa
wet feed gas as already described and is itself rator l9 wherein the heavier, less volatile por
warmed. The partially warmed dry gas then tion is eliminated from the system as a liquid
50 passes through pipe II to exchanger 2 in which through pipe 29. The vaporized portion is com
it imparts cooling to the feed gas and is in turn pressed by compressor 2| and a portion is con
further warmed. The dry gas, now warmed to a
point such that it is no longer available as a
cooling medium for feed gas, passes through pipe
55 l4 to any desired disposal system.
The auxiliary refrigerating system, mentioned
above, operates in the following manner. Vola
tile hydrocarbon liquid serving as the refrigerant
and maintained under a relatively high pressure
60 is drawn from accumulator I! through pipe It
densed by condenser 26 and is collected in ac
. The lighter highly volatile portion ,
which does not condense under the temperature
and pressure conditions imposed is eliminated
through pipe 28. The lique?ed portion is ?ashed
through pipe l6 into exchanger 4 as in normal
operation. Condensate from separator 8 is fed
into the system until such a time that su?lcient
refrigerant has been accumulated. The system
to ‘heat exchanger 4. The pressure on the liquid
is released by throttle valve or orifice |‘| located
in pipe l6. Due to the volatility of the liquid it
vaporizes on release of pressure and is thus cooled
to its boiling point under the reduced pressure
thus fractionates from the condensate an inter
mediate portion suited to the conditions. Com
ponents of too high boiling range to vaporize in 65
exchanger 4 are eliminated at separator l9 and
components of too low boiling range to condense
and on passing through heat exchanger 4 ab
under the conditions in accumulator I5 are re
sorbs heat from the feed gas passing therethrough jected there as gas. Thereafter small amounts
thereby cooling the feed gas and vaporizing still of condensate from separator 8 are introduced
more of the liquid in the usual manner of opera
into the system from time to time to make up
70 tion of this type of refrigerant. The vaporized
refrigerant along with any unvaporized portion
passes from exchanger 4 through pipe ll to sep
arator I! where vapor and liquid are separated.
The vapor passes from separator I! through pipe
for unavoidable losses of refrigerant in operation
and these added amounts are likewise fraction
ated by the system as they are added.
Us
The cold "wild” condensate collected in sepa- "
3
This arrangement whereby part of the refrig
erating load is carried by
10
condensate may be charged to the stabilizer with-.
15
out the use, of pump 33’.
thus reducing the cost of the engine.
As an example of a speci?c operation in accord~
‘In accordance with the invention, wet feed gas
containing from as little as a third of a gallon ‘to
20
three hundred pounds per square inch. In pass
25
w
ing through heat exchangers 2, It, and 6 the feed
condensate is collected in separator 8. The dry
gas is cooled to from ‘_10 degrees Fahrenheit to
gas at 45 pounds gauge and '—80 degrees Fahren
heit expands in the engine to about .13 pounds
sure under which it
requires a low temperature to recover the desired
components and a given recovery requires a lower
gauge and -125 degrees Fehrenheit, the indi— 25
cated power development of the engine being
about 340 horse power. The expanded gas, in
temperature at low pressure than that required
for higher pressures. Due to the fact that in
order to recover a large
30
35
0
40
a.
‘
The dry gas, in expanding through the engine,
is cooled by an amount depending on the ratio of
expansion of the gas in the engine. This cooling,
at the engine inlet, may vary from about 12% for
40
45 a 2:1 expansion ratio to about 50% for a 10:1 '
expansion ratio. The cold expanded
dry gas in gas in exchangers 2 and 6 is
compressed by compressor 21 to 200 pounds pres
45
itself warmed to a temperature approaching that
of the entering feed.
-~
5o. The refrigerant used in the auxiliaryrefrigerat
.55 temperature and pressure
_ i9 determine its characteristics;
may be condensed in condenser
60
65
bons such as pentane and hexane.
The temper~~
ature to which the refrigerant vapor is heated on
70 being compressed is a function of the compression
ratio used and of the temperature at its inlet
to the compressor. - Depending on the compres
sion ratio, the absolute temperature of the com
pressed vapor may be 50%, or over, higher than
75 that
at the compressor intake.
'
It will be noted that the exhaust from the
engine is held at a relatively high pressure, i. e.,
13 pounds gauge.
If the full expansion of gas 70
to atmospheric pressure were permitted the pow
er development of the engine would be almost
doubled. In addition the refrigeration avail
able from the expanded gas would be greater, 75
2,134,702
portion of the mixture a volatile refrigerant
thus reducing or eliminating that required from
the auxiliary system, the power requirement of
which would proportionately fall. Under these
conditions a more
'
would be re
comprising hydrocarbons of said mixture, cool
ing the compressed refrigerant, separating un
condensed hydrocarbons from the cooled com-_
pressed refrigerant, and passing to said ?rst
quired and there would be an excess of power
developed for which some means
mentioned cooling step the remaining refriger
would be required.
a mixture of the vapors thereof with vapors of 10
more volatile hydrocarbons the steps compris
ing subjecting a continuous stream of the vapor
'
While the operation of this invention has been
described in connection with the recovery of
higher boiling components from natural gas it
may equally well be used in connection with
ant6. hydrocarbons.
In the recovery of liquid hydrocarbons from
gas encountered in the re?ning of petroleum,
mixture vto cooling and thereby condensing :1
portion thereof and cyclically subjecting a re
such as still gas, gas produced in the cracking or
frigerant comprising hydrocarbons of said mix
polymerization of petroleum hydrocarbons, and
the gas produced in the distillation of coal, shale
and other bitumens, or any other gas contain
20
ture to compression and then to cooling and then 15
to heat interchange with said stream of vapor
mixture in said first named cooling step and
ing such lique?able components.
maintaining substantial uniformity of composi
The examples herein recited are given solely
by way of explanation and clari?cation and the
scope of this invention is limited only by the
tion of said refrigerant during the cyclic opera
20
tions thereon.
'I. In the recovery of liquid hydrocarbons from
appended claims.
a mixture of the vapors thereof with vapors of
I claim:
-
more volatile hydrocarbons the steps comprising
1. In the recovery of liquid hydrocarbons from
a mixture of the vapors thereof with vapors of
more volatile hydrocarbons the steps comprising
25 compressing by the pressure energy of a portion
subjecting a continuous stream of the vapor mix
ture to cooling and thereby condensing a portion 25
thereof, cyclically subjecting a refrigerant com
prising hydrocarbons of said mixture to compres
of the mixture a volatile hydrocarbon refrigerant
comprising hydrocarbons of the mixture, cool
ing the compressed refrigerant and then passing
the refrigerant in heat exchange relation with
30 the mixture prior to utilization of the pressure
energy thereof in the compression step.
of liquid hydrocarbons from
a mixture of the vapors thereof with vapors of
‘sion and then to cooling and then to heat inter
change with said stream of vapor mixture in said
?rst named cooling step and passing a portion of 30
said condensate to said refrigerant and fraction
ing said portion of said condensate to the con
stituency of said refrigerant.
8. In the recovery of liquid hydrocarbons from
a; mixture of the vapors thereof with vapors of 35
more volatile hydrocarbons the steps comprising
more volatile hydrocarbons the steps comprising
cooling the mixture and condensing a portion
thereof, compressing by the pressure energy of a
portion of the mixture a volatile refrigerant
subjecting a continuous stream of the vapor mix
comprising hydrocarbons of said mixture, cool
ing the compressed refrigerant, and passing the
40 cooled compressed refrigerant in heat exchange
re‘ation with the vapor mixture in said ?rst men
ture to cooling and thereby condensing a portion
thereof, cyclically subjecting a refrigerant com
prising hydrocarbons of said mixture to compres 40
sion and then to cooling and then to heat inter
change with said stream of vapor mixture in said
?rst named cooling step, passing a portion of said
tioned cooling step.
3. In the recovery of liquid hydrocarbons from
a mixture of the vapors thereof with vapors of
45 more volatile hydrocarbons the steps comprising
condensate to said refrigerant, and removing
from said refrigerant liquid hydrocarbons thereof
passing from said heat interchange.
9. In the recovery of liquid hydrocarbons from
cooling the mixture and condensing a portion
thereof, compressing by the pressure energy of a
portion of the mixture a volatile refrigerant
a mixture of the vapors thereof with vapors of
comprising hydrocarbons of said mixture, cool
50 ing the compressed refrigerant by heat exchange
with said condensate and passing the cooled
compressed refrigerant in heat exchange rela
ture to cooling and thereby condensing a portion
tion with the vapor mixture in said ?rst men
55
tioned cooling step. ‘
more volatile hydrocarbons the steps comprising
subjecting a continuous stream of the vapor mix- r
thereof, cyclically subjecting a refrigerant com
prising hydrocarbons of said mixture to compres
sion and then to cooling and then to heat inter
change with said‘ stream of vapor mixture in said
?rst named cooling step, passing a portion of said
a mixture of the vapors thereof with vapors of
condensate to said refrigerant, and removing
from said refrigerant hydrocarbons remaining in
more volatile hydrocarbons the steps comprising
vapor form after the cooling of the compressed
4. In the recovery of liquid hydrocarbons from
cooling the mixture and condensing a portion
thereof, compressing by the pressure energy of
00 a portion of the mixture a volatile refrigerant
comprising hydrocarbons of said mixture, cool
ing the compressed refrigerant, passing the
cooled compressed refrigerant in heat exchange
relation with the vapor mixture in said ?rst
65 mentioned cooling step, separating from the re
frigerant hydrocarbons thereof remaining in
liquid form after said heat exchange step, and
then passing the refrigerant hydrocarbons in
’ vapor form to said compression step.
75
60
refrigerant.
I
10. In the recovery of liquid hydrocarbons from
a mixture of the vapors thereof with vapors of
more volatile hydrocarbons the steps comprising
cooling the mixture and condensing a portion
thereof, compressing by the pressure energy of a 65
portion of the mixture a volatile refrigerant com
prising hydrocarbons of said mixture, passing a
portion of said condensate to a stabilizing zone,
passing said compressed refrigerant in heat ex
change relation with said condensate in said zone 70
and thereby cooling the compressed refrigerant,
5. In the recovery of liquid hydrocarbons from
and passing the cooled compressed refrigerant in
a mixture of the vapors thereof with vapors of
heat exchange relation with the vapor mixture
in said ?rst mentioned cooling step.
11. In the recovery of liquid hydrocarbons from
more volatile hydrocarbons the steps comprising
cooling the mixture and condensing a portion
thereof, ‘compressing by the pressure energy of a
2, 1 84, 702
a mixture of the vapors thereof with vapors of
5
more volatile hydrocarbons the steps comprising,
a liquid portion and a dry gas portion, expanding
the dry gas portion to perform work and to cool
the dry gas, passing the cooled expanded dry
gas in heat exchange relation with the'wet gas in
Ci
- the ?rst mentioned cooling step, expending said
work in compressing the vaporized hydrocarbon
ll)
and passing
hydrocarbons remaining
in liquid form after said heat exchange.
12. In the recovery of liquid hydrocarbons from
tioned cooling step.
_ 17. The method
a mixture of the’ vapors thereof with vapors of
15
20
cooling step and adding a portionof said ‘con
25 densate to the refrigerant passing to said heat‘
exchange.
I
25
13. In the recovery of liquid hydrocarbons-from
a mixture of the vapors thereof with vapors of
hydrocarbons‘the steps comprising
30 cooling olatile
the mixture and condensing a portion
thereof, expanding the residual ‘vapors and reduc~ heated compressed refrigerant vapor in indirect
ing their temperature, utilizing said reduction of ‘heat exchange with liquid undergoing stabiliza— 30
temperature in said cooling step, by the energy of
35
tion in the stabilizing zone to transfer heat from
the compressed refrigerant vapor to the liquid
said expansion compressing a volatile refrigerant
undergoing stabilization, cooling and liquefying
the compressed refrigerant vapor, andreturning
the lique?ed refrigerant at reduced pressure to 35
cooled compressed refrigerant in heat exchange
relation to said mixture in said ?rst mentioned
cooling step.
40
45
said second mentioned cooling step.
18. The method of recovering higher boiling
'
‘ 14. In the recovery of liquid hydrocarbons from
a mixture of the, vapors thereof with vapors of
40
by indirect heat exchange with cold dry gas, fur
ther cooling and partially liquefying said wet gas
by indirect heat exchange with vaporizing hydro
ing their temperature, utilizing said reduction of
temperature in said cooling step, by the energy of
said expansion compressing a volatile refrigerant
carbon liquid refrigerant, separating the cooled
wet gas into a liquid portion and a dry gas por 45
tion, passing a part of the liquid portion at re- 1
comprising hydrocarbons of said condensate,
,50
duced pressure to the second mentioned cooling
step as a portion of the vaporizing hydrocarbon
liquid refrigerant whereby a part of said liquid is
portion of said condensate to a stabiliz
ing zone, passing the compressed refrigerant in
heat'exchange relation to said condensate in said
vaporized, separating the vaporized portion of 50
the refrigerant from the unvaporized portion‘
thereof, compressing the vaporized portion of the
refrigerant, cooling the compressed refrigerant
vapor to liquefy a portion thereof, and returning
55
the lique?ed portion of the refrigerant to the sec
ond mentioned cooling step' at reduced pressure
as a part of the vaporizing hydrocarbon liquid
60
refrigerant.
of temperature in said cooling step, by the energy
of said expansion compressing a volatile refrig
erant comprising hydrocarbons of said conden
components from ' wet hydrocarbon gas which 60
comprises cooling and partially liquefying wet
hydrocarbon gas under substantial pressure by
'
said first mentioned cooling step.
16. The method of recovering higher boiling
.
19. The method of recovering higher boiling
with cold dry gas, further
cooling and partially liquefying said wet gas by
indirect heat exchange with vaporizing hydrocar 65
bon refrigerant, separating the cooled wet gas
into a liquid portion and a dry gas portion, ex
lique?able components from wet hydrocarbon gas‘
75
step, passing a part of the liquid portion of the
wet gas at reduced pressure to the second men
tioned cooling step as a portion of the vaporizing
hydrocarbon refrigerant, separating the vaporized
75
2,134,702
6
tion of the liquid portion of the wet gas at re
portion of the refrigerant from the unvaporized
portion, expending said work in compressing the
vaporized portion of the refrigerant, cooling and
partially liquefying the compressed refrigerant
vapor and returning the lique?ed portion at re
duced pressure to the second mentioned cooling
step as a portion of the vaporizing hydrocarbon
duced pressure to the second mentioned cooling
step as a part of the vaporizing hydrocarbon re
frigerant, separating the vaporized portion of the
refrigerant from the unvaporlzed portion, ex
pending said work in compressing the vaporized
refrigerant whereby it is heated, passing the re
maining portion of the liquid portion of the wet
gas to a stabilizing zone, passing the heated com
refrigerant.
20. The method of recovering stable motor
fuel from wet hydrocarbon gas which comprises
pressed refrigerant vapor in indirect heat ex- 10
cooling and partially liquefying wet hydrocarbon
the stabilizer to transfer heat from the com
gas under substantial pressure
pressed reirigerant vapor to the stabilizer where
by the liquid portion of the wet gas is stabilized,
indirect heat
exchange with cold dry gas, further cooling and
partially liquefying said wet gas by indirect heat
change with liquid undergoing stabilization in
cooling and partially condensing the compressed 115
vaporizing hydrocarbon refriger- ' refrigerant vapor, and returning the condensed
with
15 exchange
ant, separating the cooled wet gas into a liquid
20
portion and a dry portion, expanding the dry gas
portion to perform work and to cool the gas, the
cooled expanded gas being the cold dry gas in
the ?rst mentioned cooling step, passing a por
portion to the second mentioned cooling step at
reduced pressure as a portion of the hydrocarbon -
refrigerant.
OSWALD C. BREWSTER.
\
20
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