Treatment of cyanide byproduct in nitrile production
AssigneeThe Lummus Company
InventorsAbraham P. Gelbein, Joon T. Kwon
Life of this patent
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Abstract
Hydrogen cyanide, carbon dioxide and ammonia present in a nitrile production effluent are recovered as an aqueous solution containing ammonium carbonate and ammonium cyanide. The cyanide is hydrolyzed to ammonia and carbon monoxide, followed by recovery of carbon monoxide, carbon dioxide and ammonia, all free of cyanide, from the hydrolyzed solution. In this manner, ammonium values are recovered from the cyanide byproduct and recovered streams are free of cyanide.
Claims16
In a process for producing nitriles wherein a nitrile production effluent includes gaseous ammonia, carbon dioxide and hydrogen cyanide, the improvement comprising:
- a. recovering from the nitrile production effluent hydrogen cyanide and at least a portion of the ammonia and carbon dioxide as an aqueous solution, said aqueous solution containing ammonium carbonate and ammonium cyanide;
- b. hydrolyzing cyanide present in said aqueous solution to ammonia and carbon monoxide;
- c. stripping carbon monoxide, carbon dioxide, water vapor and un-hydrolyzed hydrogen cyanide from the aqueous solution produced in step b to recover water free of cyanide and a stripped gas;
- d. separating the stripped gas into a gaseous stream of ammonia and carbon monoxide and an aqueous solution containing ammonium carbonate and ammonium cyanide;
- e. stripping carbon dioxide free of hydrogen cyanide from said aqueous solution from step d;
- and
- f. passing at least a portion of the aqueous solution from step e to step b.
In a process for producing nitriles wherein a nitrile production effluent includes gaseous ammonia, carbon dioxide and hydrogen cyanide, the improvement comprising:
- a. recovering from the nitrile production effluent hydrogen cyanide and at least a portion of the ammonia and carbon dioxide as an aqueous solution, said aqueous solution containing ammonium carbonate and ammonium cyanide;
- b. stripping from the aqueous solution of step a carbon dioxide, water vapor and hydrogen cyanide to recover water free of cyanide and a stripped gas;
- c. separating the stripped gas into a gaseous stream of ammonia and an aqueous solution containing ammonium carbonate and ammonium cyanide;
- d. hydrolyzing cyanide present in the aqueous solution from step c to ammonia and carbon monoxide;
- e. stripping carbon dioxide and carbon monoxide, free of cyanide, from the aqueous solution from step d;
- and
- f. passing at least a portion of the aqueous solution from step e to step b.
Dependencies are inferred from the claim text.