Patent ID: 6106790
Filing Date: 2000-08-22
Classification: B01D,Y02C

Abstract:
A process of destroying NF.sub.3 to less than 10 ppm in a gas containing NF.sub.3 and one or more gas components selected from the group consisting of N.sub.2, O.sub.2, F.sub.2, CF.sub.4, C.sub.2 F.sub.6, CHF.sub.3, SF.sub.6 and mixtures thereof by contacting said gas at a temperature in the range of 150 to 550.degree. C. with at least one fluidized bed of metal particles, selected from the group consisting of iron, nickel, copper, calcium, magnesium, manganese, cobalt, tin and mixtures thereof, capable of reacting with NF.sub.3 wherein substantially all of said particles have a particle size no greater than 300 microns, either: (a) alternately with one of a plurality of switching parallel connected fluidized beds of metal particles and switching beds when the height of the bed being contacted with said gas increases due to bed expansion to a bed height corresponding to substantially stoichiometric reaction of NF.sub.3 with said metal particles; or (b) with a single fluidized bed where said metal particles are substantially continuously being added to an inlet near a base of said fluidized bed and metal particles that have been reacted with said NF.sub.3 are substantially continuously being removed above said inlet and below a freeboard of said metal particles that have been reacted with said NF.sub.3 of said fluidized bed due to bed expansion.