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1. US5698171 - Regenerative method for removing sulfides from gas streams

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[ EN ]
We claim:
1. A method for the removal of sulfides from gaseous streams comprising
(a) contacting the sulfide containing gas stream in a contacting zone with an aqueous scavenging mixture, said scavenging mixture comprising an aminal scavenging compound, an inorganic base and a polyvalent metal oxidation catalyst for a period of time to at least partially reduce the level of hydrogen sulfide in the gas stream,
(b) regenerating at least a portion of said aminal scavenging compound with a gas selected from the group consisting of air, oxygen enriched air, oxygen, ozone enriched air and ozone in a regeneration zone, and
(c) returning at least a portion of the aqueous scavenging mixture to the contacting zone.
2. A method as in claim 1 wherein said aminal scavenging compound is a reaction product between
(a) an aldehyde and
(b) an nitrogen compound.
3. A method as in claim 2 wherein said aminal scavenging compound is a reaction product between
(a) an aldehyde selected from the group consisting of hydrous and anhydrous forms of formula (II): Where R is selected from the group consisting of: (i) hydrogen; (ii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 50 carbons; (iii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 50 carbons comprising at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and halogen; (iv) a substituted or unsubstituted polymeric chain; (v) a substituted or unsubstituted dimer (vi) a mono or polyaldehyde, and
(b) an nitrogen compound of formula (III) Wherein R 1 and R 2 are independently selected from the group consisting of: (i) hydrogen; (ii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 50 carbons; (iii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 50 carbons comprising at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and halogen; (iv) a substituted or unsubstituted polymeric chain; and (v) a direct bond to any other of R 1 and R 2 ;
wherein R 1 and R 2 may be individually bonded to one another.
4. A method as in claim 3 wherein said aldehyde is selected from the group consisting of formaldehyde, paraformaldehyde, glyoxal, acetaldehyde, butyraldehyde, benzaldehyde, N-(2-hydroxyethyl)dioxazine and oleylaldehyde.
5. A method as in claim 4 wherein said nitrogen compound is selected from the group consisting of methylamine, ethylamine, propylamine, isopropyl amine, oleylamine, ethylene diamine, diethylene triamine, dimethylamine, diethylamine, monoethanolamine, diethanolamine, morpholine, piperazine, thiomonoethanolamine and chlorooleylamine.
6. A method as in claim 3 wherein said nitrogen compound is selected from the group consisting of methylamine, ethylamine, propylamine, isopropyl amine, oleylamine, ethylene diamine, diethylene triamine, dimethylamine, diethylamine, monoethanolamine, diethanolamine, morpholine piperazine, thiomonoethanolamine and chlorooleylamine.
7. A method as in claim 3 wherein said reaction product comprises at least one of the compounds selected from the group consisting of compounds of formula I, IV and formula V: where n is an integer from 1 to 1000 and each of R 1, R 2, R 3, R 4, and R 5 is independently selected from the group consisting of (i) hydrogen; (ii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 20 carbons, (iii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 20 carbons comprising at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and halogen; (v) a substituted or unsubstituted polymeric chain; and (v) a direct bond to any other of R 1, R 2, R 3, R 4, and R 5 ;
wherein R 1, R 2, R 3, R 4, and R 5 may be individually bonded to one another.
8. A method as in claim 3 wherein said inorganic base is selected from the group consisting of group I and group II ions.
9. A method as in claim 8, where said inorganic base is selected from the group consisting of sodium and potassium.
10. A method as in claim 7 wherein said scavenging compound is a polycyclic polyaza compound.
11. A method as in claim 10 wherein said polycyclic polyaza compound is a hexahydro triazine.
12. A method as in claim 7 wherein said scavenging compound is an imine.
13. A method as in claim 1 wherein said polyvalent metal oxidation catalyst is selected from the group consisting of iron, copper, vanadium, manganese, platinum, tungsten, nickel, mercury, tin and lead.
14. A method as in claim 13 wherein said polyvalent metal oxidation catalyst is selected from the group consisting of iron and vanadium.
15. A method as in claim 1 wherein said scavenging mixture comprises a molar ratio of x:y:z where x is molar equivalents of said scavenging compound, y is molar equivalents of said inorganic base, and z is molar equivalents of said polyvalent metal oxidation catalyst, all present in diluent water present at up to 99.5 percent by weight of the total mixture, and wherein x, y, and z are each independently chosen numbers between 1 and 10,000.
16. A method as in claim 15 wherein y and z are each independently chosen numbers between 1 and 100.
17. A method as in claim 16 wherein y and z are each independently chosen numbers between 1 and 10.
18. A method as in claim 15 wherein said scavenging mixture comprises water in a quantity of 25 percent by weight to 99.5 percent by weight of the total composition.
19. A method as in claim 15 wherein said scavenging mixture comprises water in a quantity of 50 percent by weight to 99.5 percent by weight of the total composition.
20. A method for the removal of sulfides from gaseous streams comprising
(a) contacting the sulfide containing gas stream with a scavenging mixture, said scavenging mixture comprising at least one of the compounds selected from the group consisting of compounds of formula I, IV and formula V: where n is an integer from 1 to 1000 and each of R 1, R 2, R 3, R 4, and R 5 is independently selected from the group consisting of (i) hydrogen; (ii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 20 carbons, (iii) a substituted or unsubstituted, saturated or unsaturated, linear, branched or cyclic hydrocarbon chain of 1 to 20 carbons comprising at least one heteroatom selected from the group consisting of nitrogen, oxygen, sulfur and halogen; (v) a substituted or unsubstituted polymeric chain; and (v) a direct bond to any other of R 1, R 2, R 3, R 4, and R 5 ;
wherein R 1, R 2, R 3, R 4, and R 5 may be individually bonded to one another;
an inorganic base selected from a group consisting of group I and group II ions; and
a polyvalent metal oxidation catalyst selected from the group consisting of iron, copper, vanadium, manganese, platinum, tungsten, nickel, mercury, tin and lead;
(b) regenerating at least a portion of the scavenging compound with a gas selected from the group consisting of air, oxygen enriched air, oxygen, ozone enriched air and ozone in a regeneration zone, and
(c) returning at least a portion of the aqueous scavenging mixture to the contacting zone.