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Патент USA US3100685

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Aug. 13, 1963
J. R. SHAW ETAL
3,100,680
METHOD OF INHIBITING FOAMING OF DIETHANOLAMINE
SOLUTIONS IN TREATING GASES
Filed DGO. 27, 1960
REFLUX
50ACID GAS
ACUMLTOR
26
HYDROCABN SEPARTO
HYPDRUOCAIFBNES
Ai
W
p
United States Patent O " lCe
1
' `arrasar
Patented Aug. i3, 1963
2.
`mixture of acidic gases and hydrocarbons by contacting
3,100,680
said mixture with »an aqueous diethanolamine solution
` ANOLAMINE SOLUTÍÜNS TN TREATING GASES
foaming, said improvement comprising contacting said
METHOD OF
ITING FOAMTNG OF DIETH
John R. Shaw and Henry L. Vornkahl, Port Arthur, Tex.,
. assignors to Gulf Gil Corporation, Pittsburgh, Pa., a
corporation of Pennsylvania
Filed Dec. 27, 1960, Ser. No. 78,729
8 Claims. (Cl. 23---3)
upon contacting conditions normally tending to induce
mixture tof acidic gases and hydrocarbons with an aqueous
diethanolamine solution containing a small amount, suffi
cient to inhibit the normal foaming tendency, of an anti
foam composition comprising ‘a mixture of `a light mineral
oil and cottonseed oil. Our invention is further based
upon a novel antifoam composition, particularly adapted
This invention «relates to a new and improved antifoam 10 for use .in a process for separating acidic gases, suc-h as
`hydrogen sulñde yand carbon dioxide, from a mixture of
a process for `separating acidic gases, such as hydrogen
acidic gases and hydrocarbons with `an ‘aqueous diethanol
composition and to Va method of preventing foaming in
sulñde and carbon dioxide, from gaseous and liquid
hydrocarbon mixtures.
»amine solution, said antifoam composition comprising a
mixture of a light mineral oil and cottonseed oil.
The presence of hydrogen -sulñde ‘and carbon dioxide in 15
The mineral oil incorporated in the iantifoam composi
gaseous and liquid hydrocarbons makes further use of such
hydrocarbons undesirable in most instances. Once sep
arated, however, the hydrogen sulfide can be converted
into `sulfur or otherwise utilized, the carbon dioxide can
tion 'according to our invention lis preferably a light
mineral oil having a viscosity of about 30 to about 50
SUS at 700°. Mineral oils which yare made up predomi
nantly of paraflinic constituents are preferred. However,
-be puriñed for further use, and the hydrocarbons can be 20 aromatics and oleñns can Ialso be present. Thus, a light
recovered for use las such or converted into useful
gas oil «such as one obtained in -a iiuid catalytic cracking
products. Many processes have been developed forcep
process and which consists essentially of parafñnic and
arating hydrogen vsuliide and carbon dioxide from gaseous
aromatic constituents `and :a small amount of oleñns is an
and »liquid hydrocarbon mixtures. One of the more 25 example ‘of a preferred mineral oil with which the cotton
desirable commercial processes for separating acidic
seed oil is admixed.
gases from gaseous and liquid hydrocarbon mixtures
'The cottonseed oil4 employed in the antifoam composi
thereof comprises scrubbing the so-called “sour” hydro
tion according to our invention can be either a crude grade
packed or bubble plate .
carbon mixture in a spray,
thereof or a refined oil.
Cottonseed oil typically has a
column with an aqueous diethanolamine solution ño'wing 30 specific gravity ‘of about 0.920 to 0.930; »a saponiiication
countercurrently to the hydrocarbon stream. The aque
value of -about 190 to `200; an iodine value of about 100
ous diethanolamine solution absorbs the .acidic gases and
to 120; land a titer of 32° to 36° C.
a “sweet” hydrocarbon stream is obtained. 'The «ab
The proportions of the mineral oil and cottonseed oil
sorbed acidic gases are thereafter >separated from the
in the ant-ifoam composition of the invention may vary
diethanolamine solution by heating, which regenerates the 35 over relatively Wide limits. The mine-ral ori-l, for example,
diethanolamine solution for further use.
can comprise about 20 to about 90 percent by weight of
The efficiency of »a process for separating acidic gases
the antifoam composition land the cottonseed oil can
from a hydrocarbon ' mixture by »absorption with an
comprise of 80 to about 10 percent by weight of the com
aqueous diethanolamine solution is, among other things,
position. A preferred composition ‘in treating a tail gas
dependent upon the efficiency of the contactor in which 40 obtained from a fluid catalytic cracking process com
the absorption takes place. Thus, to obtain optimum sep
prises about 50 to about 75 percent by weight of a light
aration of the acidic gases from the hydrocarbon mixture,
mineral oil and about 25 to about 50 percent by weight
the contacter should provide for intimate contact of the
cottonseed oil, ‘an especially preferred composition corn
`hydrocarbon mixture with the diethanolamine solution.
prising about 75 percent by weight of a fluid catalytically
Various“ contactors of the spray, packed and bubble plate
cracked gas oil and »about 25 percent 'by weight of cotton
type have been designed to give optimum contact between
seed oil. The amount of the antifoam composition em
coÄùntercurrently ïñowing streams. The eihciency of such
ployed in treating a sour hydrocarbon stream with lan
contractors, however, is greatly reduced if foaming' of one
aqueous ldiethanolamine solution depends upon the
or both of the ñowing `streams occurs. In the past, some
amount of hydrocarbon stream treated and the quantity of
`foaming has been encountered in countercurrently con 50 diethanolamine solution charged. In most instances,
tacting a mixture of` acidic gases and hydrocarbons with
however, the antifoam composition comprises about 0.001
an aqueous diethanolamine solution. Foaming in the'
to about 0.01 percent by weight based on the weight of
contactor is undesirable because it reduces the extractive
the aqueous diethanollamine used, the preferred amount
eifect‘of the dietbanolamine solution for lack of intimate
being ordinarily of the order of `about `0.002 to about
55 0.005 percent. yIn any event, the amount used is suñìcient
contacting.
t
'
We have discovered that the foaming normally tending
to substantially reduce the normal foaming tendency of
to‘occur in countercurrently contacting a mixture of »acidic
the diethanolamine solution.
'llhe `accompanying drawing is illustrative of a flow
gases and hydrocarbons with an aqueous diethanolamine
diagram of a continuous cyclic process 'for separating
solution can be prevented by incorporating in the dietha
`nolarnine solution ‘a small amount of an antifoam com 60 hydrogen sulñde and carbon dioxide from gaseous and
liquid hydrocarbon mixtures with an aqueous diethanol
-position comprising fa mixture of `a light mineral oil and
lamine solution containing an antifoam composition of
cottonseed oil. Thus, our invention is based upon an
the invention. In order to present the flow diagram in a
improvement in a process for separating acidic gases,
simplified form, conventional equipment including flow .
`such as hydrogen sulñde and» carbon dioxide, from a
3,100,680
.
.
3
4
-
regulating valves, heat exchangers, pumps and the like
have been omitted.
number of 102 and a saponiíication number of rl95. >A
l
purified gaseous hydrocarbon stream consisting essen- Y.
Now referring to the drawing, a sour hydrocarbon
stream is introduced Aby conduit 10 into the lower portion
tially of hydrogen, nitrogen, C1 to C3 hydrocarbons and
carbon monoxide and containing some diethanolamine
solution and »antifoam composition is Withdrawn from
of contactor 12. Contactor 12 can be a spray, packed or
bubble plate column. The sour hydrocarbon stream rises
through contactor 12 countercurrently to a descending
stream of lean diethanolamine solution and antifoam
'contactor 12 through conduit 22 to hydrocarbon sepia
rator 24. A purified gaseous hydrocarbon stream con
sisting essentially of hydrogen, nitrogen, C1 to C3 hydro
composition introduced by conduit 14 into the upper por
carbons and carbon monoxide is withdrawn from hydro
carbon separator 24 through conduit 26 -for further proc
tion of contactor 12. The lean dieth-anolamine solution
in conduit 14 consists of fresh diethanolamine solution
essing or use. A rich diethanolamine solution which con
introduced by conduit 16, recycle `diethanolamin'e solution " tains antifoam composition and absorbed acidic gases is
introduced by conduit 18, and antifoam composition in
Withdrawn from contactor 121through conduit 28. The
troduced by conduit 20. Fresh diethanolamine solution
rich diethanolamine solution is then passed through filter
introduced by conduit 16 and antifoam composition in 15 32 and introduced into the upper'portion of reactivator
troduced by conduit 20 is employed to compensate for
36 at a temperature of about 212° F. .and a pressure of
any .loss which occurs in the process. A purified hydro
about 15 p.s.i.g. In reactivator 36 the diethanol-amine
carbon stream substantially free of hydrogen sulfide and
solution flows downwardly over bubble trays `and is
carbon dioxide fiows from the »top of contactor 12 through
heated to its boiling point, approximately 250° F., as it
conduit 22 to a hydrocarbon separator 24. A purified 20 reaches the bottom tray by vapors from reboiler 54. As
hydrocarbon stream is removed from hydrocarbon sepa
Y the solution approaches this temperature, the hydrogen
rator 24 through conduit 26 Ifor `further processing or
suliide and carbon dioxide are liberated from the solu
use. A rich diethanolamine solution which contains anti
tion' and removed from reactivator 36 along with vapors
foam composition -and which has absorbed hydrogen
`at a temperature of about 240° F. through conduit 38.
sulfide and carbon dioxide is removed from the base of 25 Diethanolamine solution and antifoam composition, which
contactor 12 through condi'ut 28. Any diethanolamine
is stripped of hydrogen sulfide and car-bon dioxide, pass
solution and antífoam composition which is carried out
from reactivator 36 at about 259° F. and 20 psig.
of the top of contactor 12 with the purilied hydrocarbon
through conduit 18 «for cooling and subsequent recycling
stream in conduit 22 is separated and collected in hydro
»to
contactor 12. lMake-up for any diethanolamin'e solu-> i
carbon 'separator 24. The diet‘hanolamine solution and 30 tion and/or antifoam'composition which is lost in the
antifoam composition so collected, is removed by con
_ process is introduced into conduit 14 by conduits 16 and
duit 30 and admixed with the rich diethanolamine solu
20, respectively.
tion in conduit 28. The rich diethanolaminesolution in
According to another Vembodiment of the invention, a
conduit 28 is then passed through a filter 32 and conduit
sour liquid hydrocarbon stream consisting essentially of
35
_34 to «a diethanolamine reactivator 36. In reactivator 36,
C2 to C4 hydrocarbons and hydrogen _sulfide is introduced
rich diethanolamine solution flows downwardly over-bub
into the bottom of packed contactor »12 by conduit 10 at a
ble trays in intimate contact with an upwardly flowing
temperature of 'about 100° Randa pressure of about400
stream of vapors `from reboiler 54. As the diethanola
’ p.s.i:g. The sour liquid hydrocarbon stream rises through
mine solution approaches its boiling point near the bot
the packing in the contactor countercurrently toa descend
tom of reactivator 36, hydrogen sulfide and carbon diox 40 ing 20 percent aqueous diethanollamine solutionl containing
ide are liberated and carried upwardly with the vapors.
about 0.002 to about 0.005 percent by weight of van anti- Y
Acid 'gas and vapors are removed from reactivator 36
through conduit 38 and an acid gas cooler 40L to a reflux
foam‘composition consisting essentially of about 75 per
cent -by weight of «a light mineral oil having -a viscosity of
>about 35 SUS »at 100° F. and 25 percent by weight of cot
accumulator 44 where condensate is separated from the
gas. The condensate accumulating in accumulator 44 is 45 tonseed oil. Separation of the hydrocarbons and fdietha
returned by reflux pump'46 and conduit 48 `to the top of
n'olamine solution is effected by «a differential in the specific
reactivator 36. The acid gas is vented from the top of
gravities of the two liquids.` A puriñed hydrocarbon
accumulator ¿t4-»through conduit _50 by a backpressure
l stream substantially free of hydrogen sulfide (2 gains of
controller (notshown). The yacid gas is then passed `to
a' further >recovery or disposal system (not shown).
570
hydrogen sulñ-de per gallon) flows `from the top of con
tactor 12 through conduit 22 to hydrocarbon separator
Stripped diethanolamine solution flows from the bottom
24. From hydrocarbon separator 24, puriíied hydrocar
of Vreactiva-tor 36 through cond-uit 52 to reboiler 54 Where
the solution is boiled. The vapors from the-boiling solu- .
tion pass out of the top of reboiler 54 through conduit
56 into reactivator 36 and then rise through the reacti 55
bons pass through conduit 26 and »a cooler (not shown).
The cooled hydrocarbon stream is then ready `for Ifurther
processing or use. A rich diethanolamine solution con
vator. i A lean recycle diethanolamin'e solution which :also '
_tion is removed from .contactor 12 through conduit 28 to a .
diethanol'amine reactiwatifon system las discussed labove.
It -Will be understood that the temperatures and pres
contains antifoam composition is removed from the re
activator 36 by conduit 18.
In one embodiment of the invention an absorber
stripper tail gas consisting essentially of hydrogen, nitro
taining absorbed hydrogen sulfide ¿and «antifoarn composi
sures employed in the -above »specific embodiments are
60 illustrative only 'and that other conditions can be employed
gen', C1 to C3 hydrocarbons, hydrogen sulfide, carbon ’ without departing Ifrom the scope of the invention. VLike
dioxide and carbon monoxide is introduced into the bot
« wise, the concentration of the fdiethanol'amine solution f
can vary over wide limits. ÁIn general, the ’amount of water
tom of packed contactor 12 by conduit 10 at a tempera~
in the ‘diethanolamine solution comprises about 70 to
ture of about 112° ‘F. and a pressure of about 180 psig.
‘ . The gaseous mixture then rises through the packing (1% ”
65
about `92 percent by Weight of the total solution. 'Ihe
, Raschig rings) in contactor 12. The gaseous mixture is
opti-mum amount :of water îfor Iany given separation may
intimately contacted with a descending stream of aqueous
ldiethanolamine (85 percent water and 15 percent di
experimentation. In treating 1an absorber-stripper tail gas’
vary, but this amount can readily be determined by routine'` ’ ' Y
"et-hanolamine) containing Áabout 0.002 to about 0.005 70 at a temperature of 100° to 135° F. and «a pressure of'15`0
to 180 p.s.i.g., the idiethanolamine solution advantageously
percent by Weight of anantifoam composition. The anti
contains «about 8.3 to about 88 percent by weight of water.
foam composition consists essentially of about 75 percent
Under the same conditions, an «antifoam composition con
¿b3/‘Weight light mineral oil having a viscosity of about
sisting of 75 percent by Weight of light gas oil and 25
Y35 SUS at100° Rand 25 percent by weight of cotton
seed oil having a specific gravity of 0.922, an iodine 75 n' percent by weight of oottonseed oil is used in 4an‘iounts of
15 to '25 parts per million parts of dietlranolamine solution.
3,100,680
5
6
ing, the improvement which comprises contacting said
In order to compare the eiîectiveness of an antifoam
mixture of acidic gases and hydrocarbons With an aqueous
diethanolamine solution containing a small amount, sut
iicient to inhibit the normal `foaming tendency, or an
antifoam composition comprising «about 20 to 4about 90
percent .by Weight of a light mineral oil having a vis
cosity :of about 30 to about 50 SSU at 100° F. and about
composition of the invention ina hydrocarbon svveetening
process ‘of the type deñned hereinabove, an absorber
strippertail gas «was contacted countercurrently in con
tactor `12 with a 15 percent aqueous diethanolamine solu
tion -at -a temperature of 125° F. »and a pressure of 180
p.s.i.g. The procedure was repeated using 0.001 «to 0.003
percent by weight, based on the diethanolamine solution,
of (1) light -gas oil; (2) cottonseed oil; «and (3) mixtures
80 to about 10 percent by weight of cottonsee-d oil.
2. The process of claim 1 wherein the aqueous di
of light gas oil and cottonseed oil. The results of these l0 ethanolamine solution contains about 70 to about 92 per
cent by weight of water.
tests are set -forth in the following table:
3. The process of 4claim 1 wherein the amount of the
fantifoam composition is about 0.001 to about 0.01 per
Dicthanolamiue solution
Percent by
Remarks
cent by Weight based on the weight of the diethanolamine
WithWeight
solution.
4. in a process for separating hydrogen sulfide and
carbon dioxide from a mixture .of hydrogen sulfide, car
No additive __________________________________ __ Foaming occurred.
Light gas oil--- __-
0.001 to 0. U03
Cottonseed oil _________________ __
0. 001 to 0. 003
50% light gas oil, 50% cottonseed
0. 001 to 0.003
Do.
D0.
curro
75%1light gas oil, 25% cottonseed
bon dioxide and gaseous hydrocarbons by contacting said
No foaiäxîng oc- »
or .
0.001 to 0.003
mixture with a-n aqueous d-iethanolamine solution under
.
Do.
contacting conditions normally tending to induce ioarn
20
01 .
ing, ‘the improvement which comprises contacting said
mixture of hydrogen sulfide, carbon dioxide and gaseous
in the light of the above idata, it is indeed surprising to
hydrocarbons with an aqueous diethanoiamine solution
iind that mixtures of light >gas oil and cottonseed ‘oil pre
containing 4a small amount, sufiicient to inhibit the nor
vented foaming in the separat-ion process Whereas each of
these oils alone did not prevent foaming. Typical tests 25 mal foaming tendency, of `an tantifoam `composition com
prising about 20 to about 90 percent by weight of a
on the light gas oil land cottonseed oil used in the above
light mineral oil having a viscosity of about 30 to about
specific examples `are 4‘as follows.
50 SUS at 100° F. and about 80 to about 10 percent by
Light gas oil:
Weight of cottonseed oil.
Gravity, ° APT _______________________ __
26.8
5. The process of claim 4 wherein the aqueous di
30
Specific gravity, 60°/ 60° F _____________ __ 0.8939
ethanolamine solution contains about 70 to about 92
Viscosity, SUV, sec. »at 100° F ___________ __
35.4
Distillation, gas oil, ASTM 13158-53
Ove-rpoint, ° F. __________________ __
Endpoint, ° F ____________________ __
400
650
Hydrocarbon analysis, percent by vol., ASTM
D13‘19-5‘5T»-
percent by weight .of Water.
6. The process of claim 4 wherein the amount of the
antifoam composition .is about 0.001 to about 0.01 percent
35 by Weight based ‘on lthe weight of the diethanolarnine
solution.
7. in »a process for `separating hydrogen sulfide and
Aromatics ______________________ __
41
Oleiins ______________ __ _________ __
7
bon ‘dioxide `and 4gaseous lhydrocarbons by contacting said
_______________________ __.
52
‘Anil-ine point, ° F., Gulf 147 ___________ __'
107.5
40 mixture with an aqueous `diethanolamine solution under
Saturates
Bromine number, ASTM D1158-55T
Cottonseed oil:
Gravity, ° API ______________________ __
carbon dioxide from a mixture of hydrogen sulfide, car
contacting conditions normally tending to induce foam
18.4
ing, the improvement which comprises contacting said
22.0
mixture of hydrogen sulfide, carbon dioxide and gaseous
hydrocarbons with an `aqueous idiethanolamine solution
Specific gravity, 60°/ 60° F ____________ __
y0.922 45
Viscosity, SUV, sec.
based on the Weight of the diethanolamine solution of
174.9
an `antifoam composition comprising about 50 to -about
52.6
75 percent by Weight of a light mineral oil having a vis
590
cosity of `about 30 to about 50 SUS at 100° F. Iand about
670 50 25 to about 50 percent by Weight ot" cottonseed oil.
+44
8. 1n a process for separating hydrogen sulfide and
+30
carbon dioxide from a mixture cfhydrogen suliide, car
100° F _____________________ ______
210° F _________________________ __
Flash, OC, ° F. _____________________ __
Fire, OC, ° F _______________________ __
Cloud, ° F __________________________ __
Pour, ° F ___________________________ __
Titer test, AOCS, ° F _________ __' ______ __
94.8
Physical state, Gulf 557 ______________ __
Liquid
Color, ASTM union _________________ __
bon dioxide and gaseous hydrocarbons by ¿contacting said
2.25 55
Refractive index, nD20, Gulf 345 _______ __ 1.47137
Sulfur, B, percent ____________________ __
0.03
Carbon residue, Conradson, percent ____ __
0.34
Iodine number, mod. Hanns, Gulf 18 ____ __
Saponiticat-ion number, ASTM D94 ____ __
0.11 60
102
195
it will be understood that the invention is not limited t-o
65
such illustrative examples and embodiments, tand may be
variously practiced Within the scope of the claims herein
after made.
We claim:
1. In a process ttor separating acidic vgases ’from `a mix 70
ture of acidic gases land hydrocarbons by contacting said
:mixture with »an aqueous diethanolamine solution under
contacting conditions normally tending to induce .foam
contacting conditions normally tending to induce foam
hydrocarbons With a 70 to 92 percent aqueous diethanol
amine solution containing about 0.002 to about 0.005
percent by weight based on the Weight of the diethanol
amine solution of an antifoam composition consisting
essentially of `about 75 percent by Weight of a iight
mineral oil having a viscosity of about 35 SUS »at 100° F.
While our invention has been described »above With'
reference to Various specific examples 'and embodiments,
mixture with an aqueous diethanolamine solution under
ing, the improvement which comprises contacting said
mixture of hydrogen sulfide, carbon dioxide and gaseous
Neutralization value, ASTM D974
Total acid number ____________________ __
containing `about 0.002 to about 0.005 percent by Weight
and about 25 percent by weight of cottonseed oil.
References Si‘ted in the ñle of this patent
UNITED STATES PATENTS
1,944,122
2,373,951
Fife ________________ __ Jan. 16, 1934
Evans et al ___________ __ Apr. 17, 1945
2,413,353
Hunter etal. _____ ______ Dec. 31, 1946
2,762,780
Kulalcow ___________ __ Sept. 11, 1956>
UNITED STATES PATENT DFEICE
CERTIFICATE OF CORRECTION
Patent No. 3, 100,680
August 13, 1963
John R. Shaw et al.
It is hereby certified thai“J error appears in the above numbered pat
enîl requiring correction and that the said Letters Patent should read as
corrected below.
Column 1I
--; colugm 2,
line 47, for "contractors" read -- contacter-s
line 3, for "upon" read -- under --; line 19,
for "T00 " read -~ 1000 F.
read
~-
SUS
--;
column 6,
line 7,
for "SSU"
--.
Signed and sealed this 4th day of February 1964.
SEAT»
nest.
EDWIN L. REYNOLDS
ERNEST W. SWIDER
Attesting Officer
AC ting
Commissioner of Patents
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