Patent ID: 8926928
Filing Date: 2015-01-06
Classification: B01D

Abstract:
1. A process for reducing the amount of hydrogen cyanide (HCN) discharged to atmosphere from a fluid catalytic cracking unit comprising a regenerator and a collecting means for collecting and supporting catalyst particles, wherein a flue gas containing HCN is discharged from the regenerator and is then passed to the collecting means, said process comprising: (a) adding a catalyst to the flue gas prior to entering the collecting means; (b) precipitating the catalyst in the collecting means to form a catalyst bed in the collecting means; (c) optionally, adding ammonia or an ammonia precursor to the flue gas prior to entering the collecting means, to the flue gas within the collecting means, or both; (d) reacting HCN in the flue gas in the presence of water and oxygen in the flue gas, and optional ammonia or ammonia precursor, at a temperature ranging from 200° C. to 800° C. in the presence of the catalyst bed to reduce the amount of HCN in the flue gas; and (e) discharging the flue gas containing a reduced amount of HCN to atmosphere, wherein the catalyst is one or more supported transition or lanthanide metal catalysts.