Absorption and separation of normally liquid gas contaminants

Claim 2

THE PROCESS FOR TREATING A COMBUSTIBLE SYNTHESIS GAS MIXTURE DERIVED FROM FOSSIL FUELS BY CARBONIZATION, CRACKING, PARTIAL COMBUSTION OR WATER GAS REACTION CONTAINING ACID GAS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN SULFIDE AND CARBON DIOXIDE TO REMOVE MINOR AMOUNTS IN THE GAS MIXTURE OF NORMALLY LIQUID CONTAMINANTS SELECTED FROM THE GROUP CONSISTING OF NON-ACIDIC SULFUR COMPOUNDS AND HYDROGEN CYANIDE WHICH COMPRISES: A. PASSING A DIALKYL ETHER OF A POLYETHYLENE GLYCOL SOLVENT HAVING 1-8 CARBON ATOMS IN EACH ALKYL GROUP AND 3-8 ETHYLENE UNITS IN INTIMATE CONTACT WITH THE GAS MIXTURE IN AN ABSORPTION ZONE TO EFFECT ABSORPTION OF AT LEAST A MAJOR PORTION OF THE NORMALLY LIQUID CONTAMINANTS; B. PASSING THE SOLVENT CONTAINING ABSORBED NORMALLY LIQUID CONTAMINANTS TOGETHER WITH SOME DISSOLVED ACID GAS TO A VOLATILIZATION ZONE TO VAPORIZE THE NORMALLY LIQUID CONTAMINANTS AND ACID GASES FROM THE SOLVENTS; C. COOLING THE MIXTURE OF VAPORS OF NORMALLY LIQUID CONTAMINANTS AND ACID GAS VAPORIZED FROM THE SOLVENT TO EFFECT CONDENSATION OF THE NORMALLY LIQUID CONTAMINANTS;

Claim 3

A process as claimed in claim 1 wherein the solvent containing the absorbed normally liquid contaminants together with some dissolved acid gas is prior to passage to the voLatilization zone passed to a flashing zone maintained at a pressure lower than the pressure in the absorption zone to effect liberation of some of the acid gas in the solvent.

Claim 4

A process as claimed in claim 2 wherein the acid gas liberated in the flashing zone is returned to the absorption zone.

Claim 5

A process as claimed in claim 1 wherein cooling of vapors of normally liquid contaminants vaporized from the solvent is effected in stages at decreasing temperatures to produce and collect separate streams of condensate having different boiling points.

Claim 6

A process as claimed in claim 1 wherein substantially all the normally liquid contaminants and substantially all the hydrogen sulfide contained in the gas mixture is absorbed in the solvent in the absorption zone.

Claim 7

A process as claimed in claim 1 wherein the gas mixture after contact with the solvent in the absorption zone is passed to a second absorption zone in intimate contact with solvent to effect absorption of substantially all of the acid gas remaining in the gas mixture to produce a product gas substantially free of normally liquid contaminants and acid gas and the solvent containing the acid gas from the second absorber is passed to a stripping zone to liberate a gas containing primarily acid gas.

Claim 8

A process as claimed in claim 6 wherein the solvent from the second absorption zone prior to stripping is subjected to flashing at reduced pressure to release a portion of the gases from the solvent which are returned to the second absorption zone.

Claim 9

A process as claimed in claim 1 wherein substantially all the acid gas and normally liquid contaminants are removed in the absorption zone and a product gas substantially free of acid gas and liquid contaminants is discharged from the absorption zone, and wherein the solvent containing the liquid contaminants and the acid gas from the absorption zone is first subjected to flashing at a pressure lower than the absorption zone to liberate a portion of the more volatile constituents which are returned to the absorption zone and the solvent containing the acid gas and normally liquid contaminants is passed to a stripping zone wherein gases consisting primarily of acid gases are released from the solvent and the solvent containing liquid contaminants is passed to a second stripping zone wherein the liquid contaminants are volatilized and collected, and the solvent from the second stripping zone is returned to the absorption zone.

Claim 10

A process as claimed in claim 1 wherein contact of the solvent with the gas mixture in the absorption zone is effected at a temperature of 10* to 120*F. and a pressure of 100 to 2000 pounds per square inch absolute and wherein vaporization of the normally liquid contaminants is effected in a stripping zone by the introduction of steam at a temperature in the stripping zone within the range of 100* to 350*F. and a pressure of 1 to 60 pounds per square inch absolute.

Claim 11

A process as claimed in claim 1 wherein the solvent is a mixture of dimethylethers of polyethylene glycol.

Claim 12

A process for treating a gas mixture containing as the major component combustible gases selected from the group consisting of methane, carbon monoxide and hydrogen together with lesser amounts of acid gas selected from the group consisting of hydrogen sulfide and carbon dioxide and minor amounts of normally liquid contaminants selected from the group consisting of non-acidic sulfur compounds and hydrogen cyanide to produce a combustible gas as one product substantially free of acid gas and normally liquid contaminants and to produce as another product an acid gas substantially free of combustible components and normally liquid contaminants and to produce as a third product normally liquid contaminants which comprises: a. passing the gas mixture upwardly through an elongated vertical absorption column countercurrent and in intimate contact with a downwardly flowing liquid solveNt composed of a mixture of dimethylethers of polyethylene glycols to effect absorption of substantially all of the normally liquid contaminants and all of the acid gas at a temperature within the range of 10* - 120*F. and a pressure of 100 - 2000 pounds per square inch absolute; b. releasing combustible gas substantially free of normally liquid contaminants and containing less than 5 parts per million hydrogen sulfide; c. passing the solvent containing the absorbed normally liquid contaminants and acid gas together with minor amounts of combustible gas to a flashing zone maintained at a pressure at least 50 pounds lower than the pressure in the absorption zone to effect liberation of dissolved combustible gas; d. returning the liberated gases from the flashing zone to the absorption tower; e. passing the solvent from the flashing zone to a stripping tower maintained at a temperature of from about 200* to 400*F. and a pressure within the range of 1 to 100 pounds per square inch absolute; f. introducing steam into the bottom of the stripping tower to strip the solvent in the tower of acid gas substantially free of other constituents; g. passing the solvent substantially free of acid gas from the bottom of the stripping column to a second stripping column maintained at a temperature of about 200* to 350*F. and a pressure of about 1 to 20 pounds per square inch absolute; h. introducing steam into the second stripping tower to vaporize the normally liquid contaminants together with very minor amounts of acid gas; i. condensing and collecting the normally liquid contaminants; and j. returning the lean solvent from the bottom of the second stripping column to the top of the absorption column.

Claim 13

A process for treating a gas mixture containing as the major component combustible gases selected from the group consisting of methane, carbon monoxide and hydrogen together with lesser amounts of acid gas selected from the group consisting of hydrogen sulfide and carbon dioxide and minor amounts of normally liquid contaminants selected from the group consisting of non-acidic sulfur compounds and hydrogen cyanide to produce a combustible gas as one product substantially free of acid gas and normally liquid contaminants and to produce as another product an acid gas substantially free of combustible components and normally liquid contaminants and to produce as a third product normally liquid contaminants which comprises: a. passing the gas mixture upwardly through an elongated vertical absorption column countercurrent and in intimate contact with a downwardly flowing liquid solveNt composed of a mixture of dimethylethers of polyethylene glycols to effect absorption of substantially all of the normally liquid contaminants and all of the acid gas at a temperature within the range of 10* - 120*F. and a pressure of 100 - 2000 pounds per square inch absolute; b. releasing combustible gas substantially free of normally liquid contaminants and containing less than 5 parts per million hydrogen sulfide; c. passing the solvent containing the absorbed normally liquid contaminants and acid gas together with minor amounts of combustible gas to a flashing zone maintained at a pressure at least 50 pounds lower than the pressure in the absorption zone to effect liberation of dissolved combustible gas; d. returning the liberated gases from the flashing zone to the absorption tower; e. passing the solvent from the flashing zone to a stripping tower maintained at a temperature of from about 200* to 400*F. and a pressure within the range of 1 to 100 pounds per square inch absolute; f. introducing steam into the bottom of the stripping tower to strip the solvent in the tower of acid gas substantially free of other constituents; g. passing the solvent substantially free of acid gas from the bottom of the stripping column to a second stripping column maintained at a temperature of about 200* to 350*F. and a pressure of about 1 to 20 pounds per square inch absolute; h. introducing steam into the second stripping tower to vaporize the normally liquid contaminants together with very minor amounts of acid gas; i. condensing and collecting the normally liquid contaminants; and j. returning the lean solvent from the bottom of the second stripping column to the top of the absorption column.

Claim 14

The process for treating gas mixture derived from fossil fuels by carbonization, cracking, partial combustion or water gas reaction containing acid gas selected from the group consisting of hydrogen sulfide and carbon dioxide to remove minor amounts in the gas mixture of normally liquid non-acidic sulfur compounds which comprise: a. passing a dialkyl ether of a polyethylene glycol solvent having 1-8 carbon atoms in each alkyl group and 3-8 ethylene units in intimate contact with the gas mixture in an absorption zone to effect absorption of at least a major portion of the normally liquid non-acidic sulfur compounds; b. passing the solvent containing absorbed normally liquid non-acidic sulfur compounds together with some dissolved acid gas to a volatilization zone to vaporize the normally liquid non-acidic sulfur compounds and acid gases from the solvent; c. cooling the mixture of vapors of normally liquid non-acidic sulfur compounds and acid gas vaporized from the solvent to effect condensation of the normally liquid non-acidic sulfur compounds; d. collecting the liquid condensate to effect separation of normally liquid non-acidic sulfur compounds from the acid gas; and e. discharging the acid gas.

Claim 15

The process for treating gas mixture derived from fossil fuels by carbonization, cracking, partial combustion or water gas reaction containing acid gas selected from the group consisting of hydrogen sulfide and carbon dioxide to remove minor amounts in the gas mixture of normally liquid non-acidic sulfur compounds which comprise: a. passing a dialkyl ether of a polyethylene glycol solvent having 1-8 carbon atoms in each alkyl group and 3-8 ethylene units in intimate contact with the gas mixture in an absorption zone to effect absorption of at least a major portion of the normally liquid non-acidic sulfur compounds; b. passing the solvent containing absorbed normally liquid non-acidic sulfur compounds together with some dissolved acid gas to a volatilization zone to vaporize the normally liquid non-acidic sulfur compounds and acid gases from the solvent; c. cooling the mixture of vapors of normally liquid non-acidic sulfur compounds and acid gas vaporized from the solvent to effect condensation of the normally liquid non-acidic sulfur compounds; d. collecting the liquid condensate to effect separation of normally liquid non-acidic sulfur compounds from the acid gas; and e. discharging the acid gas.

Claim 16

The process for treating a gas mixture derived from fossil fuels by carbonization, cracking, partial combustion or water gas reaction containing acid gas selected from the group consisting of hydrogen sulfide and carbon dioxide to remove minor amounts in the gas mixture of hydrogen cyanide which comprises: a. passing a dialkyl ether of a polyethylene glycol solvent having 1-8 carbon atoms in each alkyl group and 3-8 ethylene units in intimate contact with the gas mixture in an absorption zone to effect absorption of at least a major portion of the hydrogen cyanide; b. passing the solvent containing absorbed normally liquid contaminants together with some dissolved acid gas to a volatilization zone to vaporize the hydrogen cyanide and acid gases from the solvent; c. cooling the mixture of vapors of hydrogen cyanide and acid gas vaporized from the solvent to Effect condensation of the hydrogen cyanide; d. collecting the liquid condensate to effect separation of hydrogen cyanide from the acid gas; and e. discharging the acid gas.

Claim 17

The process for treating a gas mixture derived from fossil fuels by carbonization, cracking, partial combustion or water gas reaction containing acid gas selected from the group consisting of hydrogen sulfide and carbon dioxide to remove minor amounts in the gas mixture of hydrogen cyanide which comprises: a. passing a dialkyl ether of a polyethylene glycol solvent having 1-8 carbon atoms in each alkyl group and 3-8 ethylene units in intimate contact with the gas mixture in an absorption zone to effect absorption of at least a major portion of the hydrogen cyanide; b. passing the solvent containing absorbed normally liquid contaminants together with some dissolved acid gas to a volatilization zone to vaporize the hydrogen cyanide and acid gases from the solvent; c. cooling the mixture of vapors of hydrogen cyanide and acid gas vaporized from the solvent to Effect condensation of the hydrogen cyanide; d. collecting the liquid condensate to effect separation of hydrogen cyanide from the acid gas; and e. discharging the acid gas.