CA1078145A - Removal of co2 and/or h2s from cracked gases - Google Patents
Removal of co2 and/or h2s from cracked gasesInfo
- Publication number
- CA1078145A CA1078145A CA253,571A CA253571A CA1078145A CA 1078145 A CA1078145 A CA 1078145A CA 253571 A CA253571 A CA 253571A CA 1078145 A CA1078145 A CA 1078145A
- Authority
- CA
- Canada
- Prior art keywords
- alkali metal
- gas
- metal salt
- aqueous solution
- absorption zone
- 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
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/11—Purification; Separation; Use of additives by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1493—Selection of liquid materials for use as absorbents
-
- 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
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/151—Reduction of greenhouse gas [GHG] emissions, e.g. CO2
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Water Supply & Treatment (AREA)
- Treating Waste Gases (AREA)
- Industrial Gases (AREA)
- Gas Separation By Absorption (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for removing CO2 and/or H2S from a cracked gas by bringing the said gas, at from 20 to 60°C and under atmospheric pressure or superatmospheric pressure, into contact, in an absorption zone, with an aqueous solution of the alkali metal salts of aminoacids as the scrubbing liquor, freeing the solution leaving the absorption zone from CO2 and/or H2S by heating in a desorption zone, if necessary after first letting down the pressure, and then recycling the so-regenerated scrubbing liquor to the absorption zone, wherein the scrubbing liquor used is an aqueous solution of an alkalimetal salt of a N-dialkyl-.alpha.-aminomonocarboxylic acid.
A process for removing CO2 and/or H2S from a cracked gas by bringing the said gas, at from 20 to 60°C and under atmospheric pressure or superatmospheric pressure, into contact, in an absorption zone, with an aqueous solution of the alkali metal salts of aminoacids as the scrubbing liquor, freeing the solution leaving the absorption zone from CO2 and/or H2S by heating in a desorption zone, if necessary after first letting down the pressure, and then recycling the so-regenerated scrubbing liquor to the absorption zone, wherein the scrubbing liquor used is an aqueous solution of an alkalimetal salt of a N-dialkyl-.alpha.-aminomonocarboxylic acid.
Description
o . æ ~ ~1 J ~69/~70 REMOVAL OF C02 AND/OR H2S F`ROM CRACKED GASES
It is known to remove C02 and/or H2S from cracked gases by regenerative scrubbing using aqueous solutions of alkali metal salts of aminoacids as ~he scrubbing liquorO However, the conven~
tional process has the disadvantage that the absorption capacity of the regenerated scrubbing liquor decreases in the cour~e of time, so that all or part o~ the scrubbing liquor must be replaced at certain lntervals.
We have found an advant~geous process for removi.ng C02 and/or H2S from a cracked gas by brin~ln~ the said gas, at ~rom 20 to 60C
10 and under atmospheric pressure or superatmospheric pressure, into oontact, in an absorption zone, with an aqueous solution o~ the alkali metal salts of aminoacids as the scrubbing liquor, freeing the solution leaving the absorption zone from C02 and/or H2S by heating in a desorption zone if necessary after first lett~
ing down the pressure, and then recycling the so-regenerated scrubb-ing liquor to the absorption zone, wherein the scrubbing liquor used is an aqueous solution of an alkali metal salt of a N-dialk~l-~-aminomonocarboxylic acid.
The li~e of the scrubbing liquor is much longer in the proce~s 20 according to the lnvention than ln the conventional process.
.~ ,' ~ 7 ~ OOZ. 31,~69/370 The process ~ccording to the lnvent.ion ls used with particular advantage for removing C02 and/or H2S from a cracked gas~ containing ethylene, which is obtained by thermal cracking of vaporiz~ble hydro-carbons in the presence of steam in an indirectly heated tubular r~actor at gas exit temperatures of above 760C.
It was surprising that using the process o~ the invention the li~e of the scrubbing liquor can be extended wlthout f'urther addi~
tlves, since aerman Published Application 2,211,640 dl~closes that when using alkali metal salts o~ lower ~waminoAcldsg whlch ma~ be monosubstltuted at the amino group, as a s~:rubblng l~quor which can be regenerated, it is necess~ry to add certain compounds containlng amino groups, such as hydrazlne or phenylh~drazine, to the scrubb~
ing liquor, to extend the life of the regenerable scrubbing liquor.
The regen~rable scrubbi~g liquor used for the process of the invention is an aqueous solutlon of an alkali metal salt of a N-dialkyl-~-aminomonocarboxyllc acid carrying two alkyl groups on the nitrogen atom. Pr~ferably9 the potassium salts of the N-dialkyl~
aminomonocarboxylic acid are used. Preferred alkyl groups are those of 1 to 6 carbon atoms and especially of 1 to ~ carbon atoms, Examples o~ suitable alkyl groups are ethyl~ n propylJ lsopropylg n~bu~yl, isobutylJ pentyl, hexyl, cyclohexyl and especially methylO
ExampIes of sultable N-dialkyl-~-aminomonocarboxylic acids are N-dimethyl-~-aminopropionic acid, N diethyl-~-aminopropionic acid, - -disthylglycine and dimethylglyclnsO The use o~ an aqueous solution of the potassium salt of dimethylgylcine ls particularly advantageous, The density of the regen~ble scrubbing liquor~ at ?OOC, is advantageously ad~usted to from ~05 to 1025l especially from 1015 to 1.200 The amou~t of scrubbing l~quor to be used depends~ egO, on the amount of H2$ and C02 which ls to be removed9 on the concen~ :
tration o~ th~se compounds in ths gas mixture,c~ ~e d~rbd~ l p~ty a~:~2'p~ ar W~ !p~: andwa~k~g t~ and on the residen¢e time o~ the gas mixture. The most advantageous conditions can easily be determined ~rom case to caseO
.. . .
O~ZO 31,369/370 ~ he process is carried out under atmospherlc pressure or super~
atmospheric pressure, preferably ln the pressure range of from 5 to 50 atmospheres absolute and especially from 10 to 30 atmospheres absoluteO It may be carried out in one or several stagesO
Temperatures o~ from 20 to 60C, preferably from ~5 to 50C, are used i~ the absorption zone. The temperatures in the desorption zone are in general ~rom 95 to 110C
It may be advantageous to add an al}cali metal hydroxlde and/or an alkali metal salt o~ an acid having a pK o~ at least 5 to the 10 aqueous solution o~ the alkali metal salt of the N~dialkyl~amino-monooarboxyllc acld, Preferably, the alkali metal salt~ of acids which have a pK o~ at least 5 and are vola~ile under the temperature oonditions of the desorption ~one are added. The alkali metal hydroxide and/or alkall metal salt used are in general sodlum com~
pounds and especially potassium compounds. Examples Or su~table addi~
tives are sodium hydroxide~ sodium ~rbonate, sodium bicarbonate and especially potassium hydroxide9 potassium carbonate and potassium b$carbonate. The additive(s) may be introduced as such or ln the form of a solution, eg, an aqueous solution. The amount of additive~s) 2Q may be varied depending on the nature o~ the cracked gas, In general, from 0.001 to 1~ preferably from 0.01 to 005, m~-equivalent of the additive(s) is introduced per m~ (S.T.P.) o~ the cracked gas which is to be scrubbedO The additive(s) may be introduced oontinuouæly or batchwise.
Preferably, the process according to ths invention ls used for the treatment of ethylene-containing cracked gases which are obtal~ed by thermal cracking of vaporizable hydrocarbons ln the presence o~ -steam i~ an indirectly heated tubular reactor at gas e~lt temperatur~
above 760C. Preferably~ the gas exit temperatures are from 800 to 30 870 C and especially ~rom 810 to 860Co The weight ratiG o~ steam to vaporizable hydrocarbon is in general O ~1: 2 0 0 9 The residence time of the hydrocarbon in the tubular reactor i~ adv~ntageously from Ool to 2 seconds, pre~erably ~rom 0.1 to 1 second and especially from - . - . . . . . . . .. . .
~ ~ 7 8 ~ oOZ. ~ 6~/~70 0.1 to 0.5 ~econd~ Suitable vaporizable hydrocarbons are crude oil and especially naphtha, gasoline, diesel oil or gas oilO
It may be advantageous~ in order to avoid polymer formation and polymer deposition, ~o bring the aqueous sollltion of the alkali metal salt of the Ndlalkyl-~aminomonocarboxylic acld into contact with a hydrocarbon mixture which contains at least 40% of benzene and lts homologsJ before and/or a~ter the desorption zone and, after this treatment, to separate the hydrooarbon mixture agaln ~rom the aqueous solution. Examples o~ auitable homologs Or benzene are tolu~
10 ene, the xylenesJ ethylbenzene and methylethylbenzene~ A hydrocarbon mixture which contains ~rom 50 to 90 percent by weight of aromatics o~ 6 to 9 carbon atoms ln the molecule is used pre~erentiallyO Small amountsJ eg. up to a total o~ about 5 percent by weight, of poly~
merizable compounds, eg. styrene, c~clopentadiene or methylstyrene9 are not troublesome. Furthermore, the hydrooarbon mixture may con-tain up to 60 percent by we~ghtJ preferably up to 50 per~ent by weight, o~ non-aromatic hydrocarbons of 5 to about 12 carbon atoms in the molecule.
The treatment of the aqueous solution o~ the alkali metal salts o~ the ~-aminocarboxylic acld with the hydrocarbon mixture may be carried out directly arter the absorption o~ C02 and/or ~ S or after the desorption o~ the C02 and/or H2S. It is ad~antageous to mi~ the aqueous solution of the alkali metal salt o~ the N-dialh~l~amino monooarboxyli¢ a¢id, which is to be purifiedJ thoroughl~ with the hydro¢arbon mlxture. The treatment with the hydrocarbon may be carried out under atmospheric pressure or superatmospheric pressure eg. at up to 30 atmospheres absolute~ The amount o~ hydrocarbon mixture to be used dep~nds3 eg., on the treatment temperature, on the amount of polymer to be removed and on the extent to which the hydrocarbon mixture has been mixed with the solutlon which is to be puri~ied.
A mlxture o~ naphtha o~ boiling range ~rom 40 to 180C and _4_ -~8~'~5 ~o ~ 69/~70 steam~ in a weight ratio of naphtha to ~team o~ 1~0.5, i3 cracked in a tubular reactor~ with a gas exit temperat-ure o~ 820C and a residence time of 0.4 second. The cracked gas ls cooled to about 40 C in several stages by conventional methods and is then compressed to about ~0 bars in a turbo-compressorO To remove the H2S and C02 constituents, the cracked gas is withdrawn9 after ~he fourth stage of the compressor~ under a pressure o~ 17 bars a~d at ~C, and red at a rate o~ 60Jooo m3 (S.T,P.)/hour to the lower part o~ a tray column. The cracked gas consists essentially of ethylene~ methaneg hydro~en and propylene, the remainder being composed o~ hydrocarbons o~ 4 to 7 carbon atoms, The H2S oontent i~ 250 ppm and the C02 content 50 ppm. At the top o~ the scrubber column, 7 m3/hour o~ an aqueous solution of the potassium salt of dimethylgl~olne, of den~ity 1.17, are introduced at 40C, The laden liquor is withdrawn at the bottom of the scrubber columnJ and mixed thoroughly with a stream of 2.5 m3/hour of a hydrocarbon mixture, containing about 60% of benzene and its homologs, toluene and xylene, and the resultlng mix-ture is fed to a separator. A~ter separation of the two phases, the scrubbing liquor is introduced at the top of the regenerating column and is freed from the absorbed C02 and H2S by heatin~ to about 110C~
The liquor regenerated in this way is returned to th~ absorptlon co}umn after having undergone heat e~change. The residual contents in the scrubbed crackad gas are found to be 10 ppm of C02 and 4 ppm of H2S~ Even a~ter an on-stream period of two months, virtually no decrea~e in the activity o~ the scrubbing liquor was detectableO
; A comparative experiment is carried out a~ descr~bed in the preceding paragraph except that instead of the potasslum salt o~
dimethylglycine the potassium salt of N-methyl~ aminopropionic acld ls used. After an on-stream period of two months, the activlty of the scrubblng liquor had greatly decreased~ so that 130 ppm o~ H2S
and 30 ppm of C02 were found in the scrubbed gas~
The procedure described in the first paragraph o~ Example 1 is ~ 5 0,Z. ~1,369/~70 followed, A~ter an on~stream period of 4 monthsJ the resldual contents in the scrubbed gas had risen to 14 ppm of C02 and 17 ppm f ~2S~
If the procedure described in the preceding paragraph is followed but each day 8 kg o~ potassium hydroxide ln the form o~ a 50~ strength aqueous solution are added to the sorubbing liquor, corresponding to 0.1 mg-equivalent o~ potassium hydroxide per m~
(S.T.P.) of scrubbed gas, no decrease in the activity o~ the scrubb--ing liquor is dete¢table after an on-stream period o~ 4 monthsO
~ ':
';
:
' :~
~, ..
.
It is known to remove C02 and/or H2S from cracked gases by regenerative scrubbing using aqueous solutions of alkali metal salts of aminoacids as ~he scrubbing liquorO However, the conven~
tional process has the disadvantage that the absorption capacity of the regenerated scrubbing liquor decreases in the cour~e of time, so that all or part o~ the scrubbing liquor must be replaced at certain lntervals.
We have found an advant~geous process for removi.ng C02 and/or H2S from a cracked gas by brin~ln~ the said gas, at ~rom 20 to 60C
10 and under atmospheric pressure or superatmospheric pressure, into oontact, in an absorption zone, with an aqueous solution o~ the alkali metal salts of aminoacids as the scrubbing liquor, freeing the solution leaving the absorption zone from C02 and/or H2S by heating in a desorption zone if necessary after first lett~
ing down the pressure, and then recycling the so-regenerated scrubb-ing liquor to the absorption zone, wherein the scrubbing liquor used is an aqueous solution of an alkali metal salt of a N-dialk~l-~-aminomonocarboxylic acid.
The li~e of the scrubbing liquor is much longer in the proce~s 20 according to the lnvention than ln the conventional process.
.~ ,' ~ 7 ~ OOZ. 31,~69/370 The process ~ccording to the lnvent.ion ls used with particular advantage for removing C02 and/or H2S from a cracked gas~ containing ethylene, which is obtained by thermal cracking of vaporiz~ble hydro-carbons in the presence of steam in an indirectly heated tubular r~actor at gas exit temperatures of above 760C.
It was surprising that using the process o~ the invention the li~e of the scrubbing liquor can be extended wlthout f'urther addi~
tlves, since aerman Published Application 2,211,640 dl~closes that when using alkali metal salts o~ lower ~waminoAcldsg whlch ma~ be monosubstltuted at the amino group, as a s~:rubblng l~quor which can be regenerated, it is necess~ry to add certain compounds containlng amino groups, such as hydrazlne or phenylh~drazine, to the scrubb~
ing liquor, to extend the life of the regenerable scrubbing liquor.
The regen~rable scrubbi~g liquor used for the process of the invention is an aqueous solutlon of an alkali metal salt of a N-dialkyl-~-aminomonocarboxyllc acid carrying two alkyl groups on the nitrogen atom. Pr~ferably9 the potassium salts of the N-dialkyl~
aminomonocarboxylic acid are used. Preferred alkyl groups are those of 1 to 6 carbon atoms and especially of 1 to ~ carbon atoms, Examples o~ suitable alkyl groups are ethyl~ n propylJ lsopropylg n~bu~yl, isobutylJ pentyl, hexyl, cyclohexyl and especially methylO
ExampIes of sultable N-dialkyl-~-aminomonocarboxylic acids are N-dimethyl-~-aminopropionic acid, N diethyl-~-aminopropionic acid, - -disthylglycine and dimethylglyclnsO The use o~ an aqueous solution of the potassium salt of dimethylgylcine ls particularly advantageous, The density of the regen~ble scrubbing liquor~ at ?OOC, is advantageously ad~usted to from ~05 to 1025l especially from 1015 to 1.200 The amou~t of scrubbing l~quor to be used depends~ egO, on the amount of H2$ and C02 which ls to be removed9 on the concen~ :
tration o~ th~se compounds in ths gas mixture,c~ ~e d~rbd~ l p~ty a~:~2'p~ ar W~ !p~: andwa~k~g t~ and on the residen¢e time o~ the gas mixture. The most advantageous conditions can easily be determined ~rom case to caseO
.. . .
O~ZO 31,369/370 ~ he process is carried out under atmospherlc pressure or super~
atmospheric pressure, preferably ln the pressure range of from 5 to 50 atmospheres absolute and especially from 10 to 30 atmospheres absoluteO It may be carried out in one or several stagesO
Temperatures o~ from 20 to 60C, preferably from ~5 to 50C, are used i~ the absorption zone. The temperatures in the desorption zone are in general ~rom 95 to 110C
It may be advantageous to add an al}cali metal hydroxlde and/or an alkali metal salt o~ an acid having a pK o~ at least 5 to the 10 aqueous solution o~ the alkali metal salt of the N~dialkyl~amino-monooarboxyllc acld, Preferably, the alkali metal salt~ of acids which have a pK o~ at least 5 and are vola~ile under the temperature oonditions of the desorption ~one are added. The alkali metal hydroxide and/or alkall metal salt used are in general sodlum com~
pounds and especially potassium compounds. Examples Or su~table addi~
tives are sodium hydroxide~ sodium ~rbonate, sodium bicarbonate and especially potassium hydroxide9 potassium carbonate and potassium b$carbonate. The additive(s) may be introduced as such or ln the form of a solution, eg, an aqueous solution. The amount of additive~s) 2Q may be varied depending on the nature o~ the cracked gas, In general, from 0.001 to 1~ preferably from 0.01 to 005, m~-equivalent of the additive(s) is introduced per m~ (S.T.P.) o~ the cracked gas which is to be scrubbedO The additive(s) may be introduced oontinuouæly or batchwise.
Preferably, the process according to ths invention ls used for the treatment of ethylene-containing cracked gases which are obtal~ed by thermal cracking of vaporizable hydrocarbons ln the presence o~ -steam i~ an indirectly heated tubular reactor at gas e~lt temperatur~
above 760C. Preferably~ the gas exit temperatures are from 800 to 30 870 C and especially ~rom 810 to 860Co The weight ratiG o~ steam to vaporizable hydrocarbon is in general O ~1: 2 0 0 9 The residence time of the hydrocarbon in the tubular reactor i~ adv~ntageously from Ool to 2 seconds, pre~erably ~rom 0.1 to 1 second and especially from - . - . . . . . . . .. . .
~ ~ 7 8 ~ oOZ. ~ 6~/~70 0.1 to 0.5 ~econd~ Suitable vaporizable hydrocarbons are crude oil and especially naphtha, gasoline, diesel oil or gas oilO
It may be advantageous~ in order to avoid polymer formation and polymer deposition, ~o bring the aqueous sollltion of the alkali metal salt of the Ndlalkyl-~aminomonocarboxylic acld into contact with a hydrocarbon mixture which contains at least 40% of benzene and lts homologsJ before and/or a~ter the desorption zone and, after this treatment, to separate the hydrooarbon mixture agaln ~rom the aqueous solution. Examples o~ auitable homologs Or benzene are tolu~
10 ene, the xylenesJ ethylbenzene and methylethylbenzene~ A hydrocarbon mixture which contains ~rom 50 to 90 percent by weight of aromatics o~ 6 to 9 carbon atoms ln the molecule is used pre~erentiallyO Small amountsJ eg. up to a total o~ about 5 percent by weight, of poly~
merizable compounds, eg. styrene, c~clopentadiene or methylstyrene9 are not troublesome. Furthermore, the hydrooarbon mixture may con-tain up to 60 percent by we~ghtJ preferably up to 50 per~ent by weight, o~ non-aromatic hydrocarbons of 5 to about 12 carbon atoms in the molecule.
The treatment of the aqueous solution o~ the alkali metal salts o~ the ~-aminocarboxylic acld with the hydrocarbon mixture may be carried out directly arter the absorption o~ C02 and/or ~ S or after the desorption o~ the C02 and/or H2S. It is ad~antageous to mi~ the aqueous solution of the alkali metal salt o~ the N-dialh~l~amino monooarboxyli¢ a¢id, which is to be purifiedJ thoroughl~ with the hydro¢arbon mlxture. The treatment with the hydrocarbon may be carried out under atmospheric pressure or superatmospheric pressure eg. at up to 30 atmospheres absolute~ The amount o~ hydrocarbon mixture to be used dep~nds3 eg., on the treatment temperature, on the amount of polymer to be removed and on the extent to which the hydrocarbon mixture has been mixed with the solutlon which is to be puri~ied.
A mlxture o~ naphtha o~ boiling range ~rom 40 to 180C and _4_ -~8~'~5 ~o ~ 69/~70 steam~ in a weight ratio of naphtha to ~team o~ 1~0.5, i3 cracked in a tubular reactor~ with a gas exit temperat-ure o~ 820C and a residence time of 0.4 second. The cracked gas ls cooled to about 40 C in several stages by conventional methods and is then compressed to about ~0 bars in a turbo-compressorO To remove the H2S and C02 constituents, the cracked gas is withdrawn9 after ~he fourth stage of the compressor~ under a pressure o~ 17 bars a~d at ~C, and red at a rate o~ 60Jooo m3 (S.T,P.)/hour to the lower part o~ a tray column. The cracked gas consists essentially of ethylene~ methaneg hydro~en and propylene, the remainder being composed o~ hydrocarbons o~ 4 to 7 carbon atoms, The H2S oontent i~ 250 ppm and the C02 content 50 ppm. At the top o~ the scrubber column, 7 m3/hour o~ an aqueous solution of the potassium salt of dimethylgl~olne, of den~ity 1.17, are introduced at 40C, The laden liquor is withdrawn at the bottom of the scrubber columnJ and mixed thoroughly with a stream of 2.5 m3/hour of a hydrocarbon mixture, containing about 60% of benzene and its homologs, toluene and xylene, and the resultlng mix-ture is fed to a separator. A~ter separation of the two phases, the scrubbing liquor is introduced at the top of the regenerating column and is freed from the absorbed C02 and H2S by heatin~ to about 110C~
The liquor regenerated in this way is returned to th~ absorptlon co}umn after having undergone heat e~change. The residual contents in the scrubbed crackad gas are found to be 10 ppm of C02 and 4 ppm of H2S~ Even a~ter an on-stream period of two months, virtually no decrea~e in the activity o~ the scrubbing liquor was detectableO
; A comparative experiment is carried out a~ descr~bed in the preceding paragraph except that instead of the potasslum salt o~
dimethylglycine the potassium salt of N-methyl~ aminopropionic acld ls used. After an on-stream period of two months, the activlty of the scrubblng liquor had greatly decreased~ so that 130 ppm o~ H2S
and 30 ppm of C02 were found in the scrubbed gas~
The procedure described in the first paragraph o~ Example 1 is ~ 5 0,Z. ~1,369/~70 followed, A~ter an on~stream period of 4 monthsJ the resldual contents in the scrubbed gas had risen to 14 ppm of C02 and 17 ppm f ~2S~
If the procedure described in the preceding paragraph is followed but each day 8 kg o~ potassium hydroxide ln the form o~ a 50~ strength aqueous solution are added to the sorubbing liquor, corresponding to 0.1 mg-equivalent o~ potassium hydroxide per m~
(S.T.P.) of scrubbed gas, no decrease in the activity o~ the scrubb--ing liquor is dete¢table after an on-stream period o~ 4 monthsO
~ ':
';
:
' :~
~, ..
.
Claims (5)
1. A process for removing CO2 and/or H2S from a cracked gas, comprising:
bringing said gas, at a temperature from 20 to 60°C
and under atmospheric pressure or superatmospheric pressure, into contact, in an absorption zone, with an aqueous solution of an alkali metal salt of an aminoacid acting as scrubbing liquor, freeing the solution leaving the absorption zone from CO2 and/or H2S by heating said solution in a desorption zone and recycling the scrubbing liquor regenerated in the desorption zone to the absorption zone wherein the scrubbing liquor used is an aqueous solution of an alkali metal salt of a N-dialkyi-.alpha.-aminomonocarboxylic acid.
bringing said gas, at a temperature from 20 to 60°C
and under atmospheric pressure or superatmospheric pressure, into contact, in an absorption zone, with an aqueous solution of an alkali metal salt of an aminoacid acting as scrubbing liquor, freeing the solution leaving the absorption zone from CO2 and/or H2S by heating said solution in a desorption zone and recycling the scrubbing liquor regenerated in the desorption zone to the absorption zone wherein the scrubbing liquor used is an aqueous solution of an alkali metal salt of a N-dialkyi-.alpha.-aminomonocarboxylic acid.
2. A process as claimed in claim 1, wherein the cracked gas is an ethylene-containing gas contained by thermal cracking of vaporizable hydrocarbons in the presence of steam in an indirectly heated tubular reactor having a gas exit temperature of above 760°C.
3. A process as claimed in claim 1, wherein an alkali metal hydroxide and/or an alkali metal salt of an acid having a pK of at least 5 is added to the aqueous solution of the alkali metal salt of the N-dialkyl-.alpha.-aminomonocarboxylic acid.
4. A process as claimed in claim 1, 2 or 3, wherein the alkali metal salt of the N-dialkyl-.alpha.-aminomonocarboxylic acid is the-potassium salt of dimethylglycine.
5. A process as claimed in claim 1, 2 or 3, wherein the solution leaving the absorption zone is heated in the desorption zone after first letting down the pressure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2525780A DE2525780C2 (en) | 1975-06-10 | 1975-06-10 | Method for removing CO? 2? and H 2 S from fission gases |
| DE2525779A DE2525779B2 (en) | 1975-06-10 | 1975-06-10 | Process for the simultaneous removal of CO2 and H2 S from ethylene-containing fission gases |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078145A true CA1078145A (en) | 1980-05-27 |
Family
ID=25769013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA253,571A Expired CA1078145A (en) | 1975-06-10 | 1976-05-28 | Removal of co2 and/or h2s from cracked gases |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS51149880A (en) |
| CA (1) | CA1078145A (en) |
| FR (1) | FR2314242A1 (en) |
| GB (1) | GB1543748A (en) |
| NL (1) | NL7606234A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102658019A (en) * | 2012-05-22 | 2012-09-12 | 河北科技大学 | Composite activating potassium carbonate solution for removing carbon dioxide from flue gas |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0217487A (en) * | 1988-07-06 | 1990-01-22 | Hitachi Ltd | Frequency sensor |
| EP0671200B1 (en) * | 1994-03-09 | 1998-08-12 | The Kansai Electric Power Co., Inc. | Method for the removal of carbon dioxide from combustion exhaust gas |
| US6372121B1 (en) * | 2000-10-31 | 2002-04-16 | Nalco/Exxon Energy Chemicals, L.P. | Reducing undesired polymerization in the basic wash unit of hydrocarbon cracking process |
| DE10144890A1 (en) * | 2001-09-12 | 2003-03-27 | Basf Ag | Catalytic desulfurization of acid gas streams involves reaction with an aqueous solution of iron(III) methylglycine-diacetic acid complex followed by regeneration with oxidizing agent |
| DE102005050385A1 (en) | 2005-10-20 | 2007-04-26 | Basf Ag | Absorbent and method for removing carbon dioxide from gas streams |
| PL2026896T3 (en) | 2006-05-18 | 2017-02-28 | Basf Se | Carbon dioxide absorbent requiring less regeneration energy |
| AU2007253464B2 (en) | 2006-05-18 | 2011-06-16 | Basf Se | Removal of acid gases from a fluid flow by means of reduced coabsorption of hydrocarbons and oxygen |
| ES2301394B2 (en) * | 2006-10-31 | 2009-10-07 | Universidade De Santiago De Compostela | USE OF WATER SOLUTIONS OF GLUCOSAMINE FOR THE ELIMINATION OF CARBON DIOXIDE (CO2) AND OTHER ACID GASES. |
| EP2174700A1 (en) * | 2008-10-13 | 2010-04-14 | Siemens Aktiengesellschaft | Absorbent, method for manufacturing an absorbent and application of an absorbent |
| ES2428236T3 (en) | 2009-01-29 | 2013-11-06 | Basf Se | Absorbent agent containing amino acid and acid promoter for the elimination of acid gases |
| CA2769772C (en) | 2009-08-04 | 2014-05-06 | Co2 Solution Inc. | Formulation and process for co2 capture using carbonates and biocatalysts |
| US20130243677A1 (en) * | 2012-03-14 | 2013-09-19 | Exxonmobil Research And Engineering Company | Amine treating process for selective acid gas separation |
| CN103170318A (en) * | 2012-12-20 | 2013-06-26 | 新疆德蓝股份有限公司 | Preparation method of carbon dioxide adsorbent |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1130109B (en) * | 1960-10-12 | 1962-05-24 | Pintsch Bamag Ag | Process for removing carbon dioxide from gases and gas mixtures |
| DE1924052A1 (en) * | 1969-05-10 | 1970-12-10 | Erdoelchemie Gmbh | Process for removing CO2 and / or H2S from fission gases and device for carrying out the process |
-
1976
- 1976-05-28 CA CA253,571A patent/CA1078145A/en not_active Expired
- 1976-06-09 GB GB23820/76A patent/GB1543748A/en not_active Expired
- 1976-06-09 NL NL7606234A patent/NL7606234A/en not_active Application Discontinuation
- 1976-06-09 FR FR7617341A patent/FR2314242A1/en not_active Withdrawn
- 1976-06-10 JP JP51067209A patent/JPS51149880A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102658019A (en) * | 2012-05-22 | 2012-09-12 | 河北科技大学 | Composite activating potassium carbonate solution for removing carbon dioxide from flue gas |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51149880A (en) | 1976-12-23 |
| FR2314242A1 (en) | 1977-01-07 |
| NL7606234A (en) | 1976-12-14 |
| GB1543748A (en) | 1979-04-04 |
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