CA1128293A - Removal of acid gases from a gas mixture - Google Patents
Removal of acid gases from a gas mixtureInfo
- Publication number
- CA1128293A CA1128293A CA322,511A CA322511A CA1128293A CA 1128293 A CA1128293 A CA 1128293A CA 322511 A CA322511 A CA 322511A CA 1128293 A CA1128293 A CA 1128293A
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- CA
- Canada
- Prior art keywords
- amine
- primary
- aqueous solution
- process according
- gases
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K1/00—Purifying combustible gases containing carbon monoxide
- C10K1/08—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors
- C10K1/10—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids
- C10K1/12—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids alkaline-reacting including the revival of the used wash liquors
- C10K1/14—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids alkaline-reacting including the revival of the used wash liquors organic
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K1/00—Purifying combustible gases containing carbon monoxide
- C10K1/08—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors
- C10K1/10—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids
- C10K1/12—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids alkaline-reacting including the revival of the used wash liquors
- C10K1/14—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids alkaline-reacting including the revival of the used wash liquors organic
- C10K1/143—Purifying combustible gases containing carbon monoxide by washing with liquids; Reviving the used wash liquors with aqueous liquids alkaline-reacting including the revival of the used wash liquors organic containing amino groups
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/40—Capture or disposal of greenhouse gases of CO2
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Treating Waste Gases (AREA)
- Gas Separation By Absorption (AREA)
- Industrial Gases (AREA)
Abstract
A B S T R A C T
A process for the removal of acid gases (H2S, CO2 and COS) from a gas mixture by contacting the gas mixture with an aqueous solution containing at least 5% by weight water and comprising:
a) a physical solvent for acid gases, e. g. sulfolane;
b) a tertiary amine (e.g., methyl-diethanolamine or diethyl-monoethanolamine);
c) a secondary and/or primary amine with PKB which is not lower than the PKB of the tertiary amine minus one (e.q., di-isopropanol-amine), in an amount of 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together.
A process for the removal of acid gases (H2S, CO2 and COS) from a gas mixture by contacting the gas mixture with an aqueous solution containing at least 5% by weight water and comprising:
a) a physical solvent for acid gases, e. g. sulfolane;
b) a tertiary amine (e.g., methyl-diethanolamine or diethyl-monoethanolamine);
c) a secondary and/or primary amine with PKB which is not lower than the PKB of the tertiary amine minus one (e.q., di-isopropanol-amine), in an amount of 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together.
Description
8Z~3 REMOVAL OF ACID GASES FROM A GAS MIXTURE
The invention relates to a process for the re-moval of acid gases from a gas mixture.
Natural gas and gas mixtures which become avail-able in technical processes~ such as gasification of mineral oil fractions and coal, often contain appre-ciable amounts of acid gases~ in particular C02. In the context of this specification the term acid gases stands for H2S, C02 and COS. For envlronmental con-servation reasons and in order to achieve an attract-ive caloriflc value acid gases have to be removed toan appreciable extent before the gas mixture (e.g., the natural gas) can be used as a fuel. In case the gas mixture is to be used as a starting material for technical processes, acid gases (in particular H2S
and COS) in most cases also have to be removed because they may enhance poisoning of catalysts and/or cor-rosion of equipment.
.. .. . , ,, ~ .
- . ., - . . . . - . . .
.. . . .. .
~Z8Z~3 . .
It is well known that C02 and H2S can be removed from gas mixtures by treatment of these mi~tures with aqueous absorbents which contain a physical solvent and a primary or a secondary or a tertiary amine.
It is known (e.g., from Dutch patent application 7312490) that one molecule of C02 may react with a primary or a secondary amine in two ways, viz.
a) either with two molecules of the amine with form-ation of a carbamate (C02 + 2R2NH ~ R2NH2 R2NC00 ) or b) with one molecule of the amine with formation of a hydrogen carbonate (C02 + X20 + R2NH - ) R2N~I+ + HC03 ).
As a consequence of the equilibrium constants of the reactions depicted, most of the C02 absorbed will be in the form of a carbamate in case a primary or secondarD amine is usedj which means that for the removal of one molecule of C02 two molecules of the primary or secondary amine are consumed.
Because with tertiary amines the reaction described under a) cannot take place, only formation of hydrogen carbonate can occur, which means that only one mole-cule of a tertiary amine is needed to bind one mole-cule of C02.
Accordingly, removal of C02 from gases is more attractive with aqueous absorbents based on tertiary - . : :.. ~, . : - .
~iZ8Z~3 amines than with aqueous absorbents based on primary or secondary amines, because the amounts needed of the former for removal o~ a given amount of C02 are much lower in view of the fact that one molecule of 5 C2 is bound by one molecule of tertiary amine, while about two molecules of primary or secondary amine are needed for the binding of one C02 molecule. This means that in the former case regeneration facilities for the liquid absorbent loaded with acid gases can be 10 much smaller.
However, when using aqueous absorbents based on a tertiary amine for removal of acid gases for gas mixt-ures hardly any removal of COS occurs.
It is known that COS can be removed to a great 15 extent from acid gases with the aid of aqueous ab-sorbents which contain a physical solvent and a primary or a secondary amine. The reaction of COS
with the primary or secondary amine competes with the reaction of C02 with the primary or secondary 20 amine. As the latter reactlon has a more favourable equilibrium, and in general the amount of C02 present is much greater than that of COS, substantial COS
removal can only be achieved with an amount of secondary or primary amine in excess of the amount 25 needed to bind all C02.
- , ;, -.
It has now surprisingly been found that an aqueous absorbent consisting of an aqueous solution which contains a physi-cal solvent, a tertiary amine and a small amount Oe a primary an~/or a secondary amine is suitable to remove COS from gas mix-tures even when these gas mixtures contain besides COS large amounts of CO2, in case there exists a certain relationship between the basici-t~ of the tertiary amine on the one hand and the primary and/or secondary amine on the other.
Accordingly, the invention provides a process for the re-moval of hydrogen sulphide, carbon dioxide and carbonyl sulphide from a gas mixture containing these three gases, characterized in that the said gas mixture is contacted with an aqueous solution con-taining at least 5% by weight water and comprising:
a) a physical solvent for acid gases;
b) a tertiary amine;
c) a secondary and/or primary amine with PK which is not lower than the PK of the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together at a temperature at which the aqueous solution is liquid, and wherein the physical solvent is an organic compound able to dissolve the three gases, which does not react with the three gases, and which is soluble in the aqueous solution.
The invention also provides a composition of matter comprising an a~ueous solution containing at least 5% by weight water, and:
a) a physical solvent;
b) a tertiary amine;
c) a secondary and/or primary amine with PK which is not lower , . . . -:
than the PI~ o the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together;
and wherein the physical solvent is an organic compound which is able to dissolve the three gases hydrogen sulphide, carbon dio~ide, and carbonyl sulphide, which does not react with the three gases, and which is soluble in the aqueous solution.
The terms "aqueous absorbent" and "aqueous solution"
in this specification and claims stand for solutions which contain at least 5~w of water. Aqueous solutions containing ~rom 10-25~w of water are preferred.
The PK o~ a base (e.g., an amine) is defined as the B
negative logarithm of the basic dissociation constant at 25C in water thereof, in formula P [R3NH+~ ~OH¦
K = - loq [R3NI . Thus, a stronger base has a lower PK than a weaker base. The values used are those given in the book "Dissociation constant o~ organic bases in aqueous solutions'l by D.D. Perrin, But-terworths, London, 1965.
Physical solvents in the context of this speci~ication are (in general liquid) organic compounds which are able to dissolve acid gases but which do not react with the acid gases and which are soluble in the aqueous solution to be contacted with the gas mixture. As examples may be mentioned N-methyl-, : .
82~3 pyrrolldone, methanol and cyc~otetramethylene sulph-ones, in particular sulf'olane. The amounts of the physical solvent in the aqueous solution may vary between wide limits, amounts of 20 to 60% by weight being preferred.
Tertiary amines having at least one alkanol group attached to a basic nitrogen atom are preferred. They may contain one, two or three of these alkanol groups per molecule, the other groups (if any) being attached to the basic nitrogen atom in general being alkyl groups.
Very suitably the alkanol group contains two or three carbon atoms. The hydroxyl group in the alkanol group may be attached to a primary, secondary or tertiary carbon atom. Examples of very suitable tertiary amines are alkyl-dialkanolamines, e.g., methyl-diethanolamine and dialkyl-monoalkanolamines, e.g., diethyl-monoethanolamine.
The amounts of the tertiary amine in the aqueous solution may be chosen between wide limits; amounts between 10 and 60% by weigh~ are preferred.
As secondary and/or primary amines with a PK
which is not lower than the PK Of the tertiary amine minus one, morpholine and substituted morpholines, such as 2,6-dimethyl-morpholine, are very suitable.
Preference is given to secondary and/or primary amines which contain at least one alkanol group attachea to a basic nitrogen atom. S~condary amlnes are in particular preferred, although primary amines such as ethanolamine may, of course, be used. Very suitable secondary amines are those containing two alkanolamine groups, such as diethanolamine and in particular di-isopropanolamine. The amount of the secondary and/or primary amine in the aqueous solution will be chosen as low as possible to achieve a desired COS removal from the gas mixture.
In general, amounts of from 5 to 50, in particular 10 to ~0 mol.% calculated on the primary, secondary and tertiary amines together are very suitable.
In contrast to C02 one molecule of H2S reacts with one molecule of any amine, regardless whether it is a primary, secondary or tertiary one. There-fore, the present process is in particular ad-vantageous for removal of acid gases from H2S-con-tainlng gas mixtures which contain relatively large amounts of C02, because the amines in the aqueous absorbent are for the greater part tertiary ones, which is of particular advantage for C02-removal as discussed above.
- , ~ :
1~1!3293 8 - It has been ~ound that the rate of C0~ removal increases - with the rate constant at 25C of the carbamate-forming reaction of the primary or secondary amine present, . 2R2NH C02 ~ R2NCOo + R2llH . In particular amines with a rate constant a~ 25C
hi~her than 1200 m3/Kmol/sec. are ver~ sui.table to achieve quick C02 removal. ~xamples of such amines are monoethanolamine, methyl-aminoethanol, 2-eth~l-aminoethanol, mono-isopropanolamine and 2,6-dimethyl-morpholine .
- : ., .
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~Z~3 The process according to the invention may be carried out at any temperature at which the aqueous solution is liquid; in general temperatures from 15 to 55C, such as ambient temperature, are very suitable.
The pressure duril1g the process of the inYention may vary between wide limits, and in general will be chosen in dependence of the pressure in which the gas mixture from whichthe acid gases are to be re-- 10 moved, becomes available. Pressures from atmospheric to 80 bar, e.g., from 10 to 75 bar, are very suitable.
The process according to the invention can be carried out in conventional apparatus, which very suitably consists of a tray column in which the gas mixture is contacted countercurrently with the aqueous solutionO The absorbent loaded with acid gases is removed from the tray column and the acid gases are set free by heating, e.g., by stripping with steam.
The regenerated aqueous solution will in general be recycled.
EXAMPLE
The experiments were carried out in a column with a diameter of o.65 m containing 45 trays, spaced 0.4 m apart, at a temperature of 40C, a pressure of 50 bar and a gas flow of 290 m3/h.
. ~ , ;' . '.
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i~%~293 The gas mixture used, which was introduced into the bottom part of ~e column, had a COz-content of 30.1%v, a H2S-content o~ 2.1%v and a C'OS-content of 150 ppmv, the remainder consisting of methane.
The liquid absorbents used which were introduced at the top of the column contained 40%w sulfolane and 15%w water, the remainder being amine. The amount of the different amines present in the solutions used as absorbents is depicted in the Table. The circulation of the liquid absorbents was regulated in such a way that the loading of the amine (which is the amount of amine which is consumed by the acid gases according to stoichiometry) is about 80%.
As can be seen from the Table, in experiments ~
and 7 according to the invention, the COS removal is nearly complete and the relative absorbent circulation is about 1.
The absorbent circulation is a measure for the size of the regeneration facilities needed in order to treat a given amount of gas, and as can be seen from comparative experiment 1 the relative absorbent circulation is much higher in case the only amine present in the absorbent is a secondary one.
Comparative experiments 5 and 6 show that in case the absorbent contains as the only amine a .
: . . ,. :~. ~ :
tertiary one hardly any COS is removed.
From comparative experiment 3 it can be seen that COS is removed to a small extent only in case a secondary amine and a tertiary amine are present, but the PK of the former is lower than that of the tertiary amine minus one.
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The invention relates to a process for the re-moval of acid gases from a gas mixture.
Natural gas and gas mixtures which become avail-able in technical processes~ such as gasification of mineral oil fractions and coal, often contain appre-ciable amounts of acid gases~ in particular C02. In the context of this specification the term acid gases stands for H2S, C02 and COS. For envlronmental con-servation reasons and in order to achieve an attract-ive caloriflc value acid gases have to be removed toan appreciable extent before the gas mixture (e.g., the natural gas) can be used as a fuel. In case the gas mixture is to be used as a starting material for technical processes, acid gases (in particular H2S
and COS) in most cases also have to be removed because they may enhance poisoning of catalysts and/or cor-rosion of equipment.
.. .. . , ,, ~ .
- . ., - . . . . - . . .
.. . . .. .
~Z8Z~3 . .
It is well known that C02 and H2S can be removed from gas mixtures by treatment of these mi~tures with aqueous absorbents which contain a physical solvent and a primary or a secondary or a tertiary amine.
It is known (e.g., from Dutch patent application 7312490) that one molecule of C02 may react with a primary or a secondary amine in two ways, viz.
a) either with two molecules of the amine with form-ation of a carbamate (C02 + 2R2NH ~ R2NH2 R2NC00 ) or b) with one molecule of the amine with formation of a hydrogen carbonate (C02 + X20 + R2NH - ) R2N~I+ + HC03 ).
As a consequence of the equilibrium constants of the reactions depicted, most of the C02 absorbed will be in the form of a carbamate in case a primary or secondarD amine is usedj which means that for the removal of one molecule of C02 two molecules of the primary or secondary amine are consumed.
Because with tertiary amines the reaction described under a) cannot take place, only formation of hydrogen carbonate can occur, which means that only one mole-cule of a tertiary amine is needed to bind one mole-cule of C02.
Accordingly, removal of C02 from gases is more attractive with aqueous absorbents based on tertiary - . : :.. ~, . : - .
~iZ8Z~3 amines than with aqueous absorbents based on primary or secondary amines, because the amounts needed of the former for removal o~ a given amount of C02 are much lower in view of the fact that one molecule of 5 C2 is bound by one molecule of tertiary amine, while about two molecules of primary or secondary amine are needed for the binding of one C02 molecule. This means that in the former case regeneration facilities for the liquid absorbent loaded with acid gases can be 10 much smaller.
However, when using aqueous absorbents based on a tertiary amine for removal of acid gases for gas mixt-ures hardly any removal of COS occurs.
It is known that COS can be removed to a great 15 extent from acid gases with the aid of aqueous ab-sorbents which contain a physical solvent and a primary or a secondary amine. The reaction of COS
with the primary or secondary amine competes with the reaction of C02 with the primary or secondary 20 amine. As the latter reactlon has a more favourable equilibrium, and in general the amount of C02 present is much greater than that of COS, substantial COS
removal can only be achieved with an amount of secondary or primary amine in excess of the amount 25 needed to bind all C02.
- , ;, -.
It has now surprisingly been found that an aqueous absorbent consisting of an aqueous solution which contains a physi-cal solvent, a tertiary amine and a small amount Oe a primary an~/or a secondary amine is suitable to remove COS from gas mix-tures even when these gas mixtures contain besides COS large amounts of CO2, in case there exists a certain relationship between the basici-t~ of the tertiary amine on the one hand and the primary and/or secondary amine on the other.
Accordingly, the invention provides a process for the re-moval of hydrogen sulphide, carbon dioxide and carbonyl sulphide from a gas mixture containing these three gases, characterized in that the said gas mixture is contacted with an aqueous solution con-taining at least 5% by weight water and comprising:
a) a physical solvent for acid gases;
b) a tertiary amine;
c) a secondary and/or primary amine with PK which is not lower than the PK of the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together at a temperature at which the aqueous solution is liquid, and wherein the physical solvent is an organic compound able to dissolve the three gases, which does not react with the three gases, and which is soluble in the aqueous solution.
The invention also provides a composition of matter comprising an a~ueous solution containing at least 5% by weight water, and:
a) a physical solvent;
b) a tertiary amine;
c) a secondary and/or primary amine with PK which is not lower , . . . -:
than the PI~ o the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together;
and wherein the physical solvent is an organic compound which is able to dissolve the three gases hydrogen sulphide, carbon dio~ide, and carbonyl sulphide, which does not react with the three gases, and which is soluble in the aqueous solution.
The terms "aqueous absorbent" and "aqueous solution"
in this specification and claims stand for solutions which contain at least 5~w of water. Aqueous solutions containing ~rom 10-25~w of water are preferred.
The PK o~ a base (e.g., an amine) is defined as the B
negative logarithm of the basic dissociation constant at 25C in water thereof, in formula P [R3NH+~ ~OH¦
K = - loq [R3NI . Thus, a stronger base has a lower PK than a weaker base. The values used are those given in the book "Dissociation constant o~ organic bases in aqueous solutions'l by D.D. Perrin, But-terworths, London, 1965.
Physical solvents in the context of this speci~ication are (in general liquid) organic compounds which are able to dissolve acid gases but which do not react with the acid gases and which are soluble in the aqueous solution to be contacted with the gas mixture. As examples may be mentioned N-methyl-, : .
82~3 pyrrolldone, methanol and cyc~otetramethylene sulph-ones, in particular sulf'olane. The amounts of the physical solvent in the aqueous solution may vary between wide limits, amounts of 20 to 60% by weight being preferred.
Tertiary amines having at least one alkanol group attached to a basic nitrogen atom are preferred. They may contain one, two or three of these alkanol groups per molecule, the other groups (if any) being attached to the basic nitrogen atom in general being alkyl groups.
Very suitably the alkanol group contains two or three carbon atoms. The hydroxyl group in the alkanol group may be attached to a primary, secondary or tertiary carbon atom. Examples of very suitable tertiary amines are alkyl-dialkanolamines, e.g., methyl-diethanolamine and dialkyl-monoalkanolamines, e.g., diethyl-monoethanolamine.
The amounts of the tertiary amine in the aqueous solution may be chosen between wide limits; amounts between 10 and 60% by weigh~ are preferred.
As secondary and/or primary amines with a PK
which is not lower than the PK Of the tertiary amine minus one, morpholine and substituted morpholines, such as 2,6-dimethyl-morpholine, are very suitable.
Preference is given to secondary and/or primary amines which contain at least one alkanol group attachea to a basic nitrogen atom. S~condary amlnes are in particular preferred, although primary amines such as ethanolamine may, of course, be used. Very suitable secondary amines are those containing two alkanolamine groups, such as diethanolamine and in particular di-isopropanolamine. The amount of the secondary and/or primary amine in the aqueous solution will be chosen as low as possible to achieve a desired COS removal from the gas mixture.
In general, amounts of from 5 to 50, in particular 10 to ~0 mol.% calculated on the primary, secondary and tertiary amines together are very suitable.
In contrast to C02 one molecule of H2S reacts with one molecule of any amine, regardless whether it is a primary, secondary or tertiary one. There-fore, the present process is in particular ad-vantageous for removal of acid gases from H2S-con-tainlng gas mixtures which contain relatively large amounts of C02, because the amines in the aqueous absorbent are for the greater part tertiary ones, which is of particular advantage for C02-removal as discussed above.
- , ~ :
1~1!3293 8 - It has been ~ound that the rate of C0~ removal increases - with the rate constant at 25C of the carbamate-forming reaction of the primary or secondary amine present, . 2R2NH C02 ~ R2NCOo + R2llH . In particular amines with a rate constant a~ 25C
hi~her than 1200 m3/Kmol/sec. are ver~ sui.table to achieve quick C02 removal. ~xamples of such amines are monoethanolamine, methyl-aminoethanol, 2-eth~l-aminoethanol, mono-isopropanolamine and 2,6-dimethyl-morpholine .
- : ., .
: ::: : . : ' ,: ~
.: , :: . :- .::: : . :.,: . . : :
~Z~3 The process according to the invention may be carried out at any temperature at which the aqueous solution is liquid; in general temperatures from 15 to 55C, such as ambient temperature, are very suitable.
The pressure duril1g the process of the inYention may vary between wide limits, and in general will be chosen in dependence of the pressure in which the gas mixture from whichthe acid gases are to be re-- 10 moved, becomes available. Pressures from atmospheric to 80 bar, e.g., from 10 to 75 bar, are very suitable.
The process according to the invention can be carried out in conventional apparatus, which very suitably consists of a tray column in which the gas mixture is contacted countercurrently with the aqueous solutionO The absorbent loaded with acid gases is removed from the tray column and the acid gases are set free by heating, e.g., by stripping with steam.
The regenerated aqueous solution will in general be recycled.
EXAMPLE
The experiments were carried out in a column with a diameter of o.65 m containing 45 trays, spaced 0.4 m apart, at a temperature of 40C, a pressure of 50 bar and a gas flow of 290 m3/h.
. ~ , ;' . '.
,: . .
" ::
., ,. . ~ .
i~%~293 The gas mixture used, which was introduced into the bottom part of ~e column, had a COz-content of 30.1%v, a H2S-content o~ 2.1%v and a C'OS-content of 150 ppmv, the remainder consisting of methane.
The liquid absorbents used which were introduced at the top of the column contained 40%w sulfolane and 15%w water, the remainder being amine. The amount of the different amines present in the solutions used as absorbents is depicted in the Table. The circulation of the liquid absorbents was regulated in such a way that the loading of the amine (which is the amount of amine which is consumed by the acid gases according to stoichiometry) is about 80%.
As can be seen from the Table, in experiments ~
and 7 according to the invention, the COS removal is nearly complete and the relative absorbent circulation is about 1.
The absorbent circulation is a measure for the size of the regeneration facilities needed in order to treat a given amount of gas, and as can be seen from comparative experiment 1 the relative absorbent circulation is much higher in case the only amine present in the absorbent is a secondary one.
Comparative experiments 5 and 6 show that in case the absorbent contains as the only amine a .
: . . ,. :~. ~ :
tertiary one hardly any COS is removed.
From comparative experiment 3 it can be seen that COS is removed to a small extent only in case a secondary amine and a tertiary amine are present, but the PK of the former is lower than that of the tertiary amine minus one.
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~ ~ 11 L~ ~0 1 ~
~ ~xm I I I ~ ~ I I ~ ~d ~
td _ . ._.__.__ ~.~._.__ .. _.. __ ~ O
N I
~( ~ H
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.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the removal of hydrogen sulphide, carbon dioxide and carbonyl sulphide from a gas mixture containing these three gases characterized in that the said gas mixture is contacted with an aqueous solution containing at least 5% by weight water and comprising:
a) a physical solvent for acid gases;
b) a tertiary amine;
c) a secondary and/or primary amine with PKB which is not lower than the PKB of the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together at a temperature at which the aqueous solution is liquid, and wherein the physical solvent is an organic compound able to dissolve the three gases, which does not react with the three gases, and which is soluble in the aqueous solution.
a) a physical solvent for acid gases;
b) a tertiary amine;
c) a secondary and/or primary amine with PKB which is not lower than the PKB of the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together at a temperature at which the aqueous solution is liquid, and wherein the physical solvent is an organic compound able to dissolve the three gases, which does not react with the three gases, and which is soluble in the aqueous solution.
2. A process according to claim 1, characterized in that the aqueous solution contains from 10-25%wt of water.
3. A process according to claim 1, characterized in that the physical solvent is sulfolane.
4. A process according to claim 1, characterized in that the amount of physical solvent in the aqueous solution is 20-60%
by weight.
by weight.
5. A process according to claim 1, characterized in that a tertiary amine is used which has at least one alkanol group attached to a basic nitrogen atom.
6. A process according to claim 5, characterized in that the tertiary amine is methyl-diethanolamine or diethyl-monoethanolamine.
7. A process according to claim 1, characterized in that the amount of tertiary amine in the aqueous solution is between 10 and 60% by weight.
8. A process according to claim 1, characterized in that a secondary amine is used which contains at least one alkanol group attached to a basic nitrogen atom.
9. A process according to claim 8, characterized in that the secondary amine is di-isopropanolamine.
10. A process according to claim 1, characterized in that the amount of primary and/or secondary amine is from 10-30 mol.%
calculated on the primary, secondary and tertiary amines together.
calculated on the primary, secondary and tertiary amines together.
11. A composition of matter comprising an aqueous solution containing at least 5% by weight water, and:
a) a physical solvent;
b) a tertiary amine;
c) a secondary and/or primary amine with PKB which is not lower than the PKB of the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together;
and wherein the physical solvent is an organic compound which is able to dissolve the three gases, hydrogen sulphide, carbon dioxide, and carbonyl sulphide, which does not react with the three gases and which is soluble in the aqueous solution.
a) a physical solvent;
b) a tertiary amine;
c) a secondary and/or primary amine with PKB which is not lower than the PKB of the tertiary amine minus one, in an amount of from 1 to 50 mol.% calculated on the said primary, secondary and tertiary amines together;
and wherein the physical solvent is an organic compound which is able to dissolve the three gases, hydrogen sulphide, carbon dioxide, and carbonyl sulphide, which does not react with the three gases and which is soluble in the aqueous solution.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB13751/78 | 1978-04-07 | ||
| GB1375178 | 1978-04-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1128293A true CA1128293A (en) | 1982-07-27 |
Family
ID=10028708
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA322,511A Expired CA1128293A (en) | 1978-04-07 | 1979-02-28 | Removal of acid gases from a gas mixture |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS54137002A (en) |
| AU (1) | AU524713B2 (en) |
| CA (1) | CA1128293A (en) |
| DE (1) | DE2913780A1 (en) |
| MY (1) | MY8300217A (en) |
| ZA (1) | ZA791615B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116550100A (en) * | 2023-05-30 | 2023-08-08 | 江苏太湖新材料控股有限公司 | Desulfurizing agent and preparation method thereof |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1132170B (en) * | 1980-07-04 | 1986-06-25 | Snam Progetti | SELECTIVE SEPARATION PROCESS OF HYDROGEN SULFURATED FROM GASEOUS MIXTURES CONTAINING ALSO CARBON DIOXIDE |
| ZA83242B (en) * | 1982-01-19 | 1983-11-30 | Ici Plc | The removal of hydrogen sulphide from gas streams |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1279637A (en) * | 1968-10-31 | 1972-06-28 | Lummus Co | Solvent and process for acid gas scrubbing |
| US3864449A (en) * | 1973-05-17 | 1975-02-04 | Bethlehem Steel Corp | Regeneration of alkanolamine absorbing solution in gas sweetening processes |
| FR2328657A1 (en) * | 1975-10-21 | 1977-05-20 | Elf Aquitaine | H2S ENRICHMENT PROCESS FOR ACID GASES |
| DE2551717C3 (en) * | 1975-11-18 | 1980-11-13 | Basf Ag, 6700 Ludwigshafen | and possibly COS from gases |
| GB1589231A (en) * | 1977-04-21 | 1981-05-07 | Shell Int Research | Process for the removal of acidic gases |
-
1979
- 1979-02-28 CA CA322,511A patent/CA1128293A/en not_active Expired
- 1979-04-05 DE DE19792913780 patent/DE2913780A1/en active Granted
- 1979-04-05 ZA ZA791615A patent/ZA791615B/en unknown
- 1979-04-05 AU AU45769/79A patent/AU524713B2/en not_active Expired
- 1979-04-05 JP JP4040479A patent/JPS54137002A/en active Granted
-
1983
- 1983-12-30 MY MY217/83A patent/MY8300217A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116550100A (en) * | 2023-05-30 | 2023-08-08 | 江苏太湖新材料控股有限公司 | Desulfurizing agent and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| MY8300217A (en) | 1983-12-31 |
| JPS54137002A (en) | 1979-10-24 |
| DE2913780A1 (en) | 1979-10-11 |
| AU4576979A (en) | 1979-10-11 |
| ZA791615B (en) | 1980-05-28 |
| JPH0138838B2 (en) | 1989-08-16 |
| AU524713B2 (en) | 1982-09-30 |
| DE2913780C2 (en) | 1989-12-21 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |