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US 4,505,881 AGranted
Ammonium polysulfide removal of HCN from gaseous streams, with subsequent production of NH.sub.3, H.sub.2 S, and CO.sub.2
AssigneeShell Oil Company
InventorZaida Diaz
Life of this patent
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Abstract
A process for the removal of HCN from gaseous streams is described, the process being characterized by reaction of the HCN in the gaseous stream with an ammonium polysulfide solution, formation of ammonium thiocyanate in solution, decomposition of ammonium polysulfide and precipitation of sulfur from the ammonium thiocyanate solution in a stripping zone, and hydrolysis of the ammonium thiocyanate. Recycle or recovery of sulfur and hydrolysis products are contemplated.
Claims24
A process for removing HCN from a gaseous stream containing HCN comprising
- (a) contacting said gaseous stream in a contact zone with a solution containing ammonium polysulfide under conditions to convert HCN, and producing a solution containing ammonium polysulfide and ammonium thiocyanate, and a gas stream having reduced HCN content;
- (b) removing solution containing ammonium polysulfide and ammonium thiocyanate from the contact zone, and stripping H.sub.2 S and NH.sub.3 from said solution in a stripping zone, producing a remaining solution containing sulfur and having reduced ammonium polysulfide content;
- and
- (c) hydrolyzing ammonium thiocyanate in said remaining solution and producing NH.sub.3, H.sub.2 S, and CO.sub.2.
1 more element
A process for removing HCN from a gaseous stream containing HCN comprising
- (a) contacting said gaseous stream in a contact zone with a solution containing ammonium polysulfide under conditions to convert HCN, and producing a solution containing ammonium polysulfide and ammonium thiocyanate, and a gas stream having reduced HCN content;
- (b) removing solution containing ammonium polysulfide and ammonium thiocyanate from the contact zone and passing removed solution to a sour water stripping zone, forming a sour water-removed solution mixture, and stripping H.sub.2 S and NH.sub.3 from said mixture in said stripping zone, and producing a remaining solution containing sulfur and having reduced ammonium polysulfide content;
- and
- (c) hydrolyzing ammonium thiocyanate in said remaining solution and producing NH.sub.3, H.sub.2 S, and CO.sub.2.
1 more element
Dependencies are inferred from the claim text.