Search International and National Patent Collections

1. (WO2010115871) METHOD OF TREATING AN OFF-GAS STREAM AND AN APPARATUS THEREFOR

Pub. No.:    WO/2010/115871    International Application No.:    PCT/EP2010/054507
Publication Date: Fri Oct 15 01:59:59 CEST 2010 International Filing Date: Wed Apr 07 01:59:59 CEST 2010
IPC: B01D 53/14
B01D 53/52
B01D 53/75
C02F 3/02
C10K 1/12
C10L 3/10
B01D 53/50
Applicants: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
SCHREUDER, Sandra
Inventors: SCHREUDER, Sandra
Title: METHOD OF TREATING AN OFF-GAS STREAM AND AN APPARATUS THEREFOR
Abstract:
The present invention provides a method of treating an off-gas stream (80) comprising NH3 and H2S to provide a sulphate stream (910), the method comprising the steps of : (i) providing a first off-gas stream (80) comprising NH3, H2S, CO2 and optionally one or more of HCN, COS and CS2; (ii) passing the first off-gas stream (80) to an incinerator (300) to oxidise NH3, H2S, and optionally one or more of HCN, COS and CS2 to provide a second off-gas stream (310) comprising N2, H2O, SO2 and CO2; (iii) scrubbing the second off-gas stream (310) with a first aqueous alkaline stream (380, 876a) in a caustic scrubber (350) to separate SO2 and a part of the CO2 from the second off-gas stream to provide a spent caustic stream (360) comprising carbonate and one or both of sulphite and bisulphite and a caustic scrubber off-gas stream (370) comprising N2 and CO2; and (iv) passing the spent caustic stream (360) to an aerator (900) comprising sulphur-oxidising bacteria in the presence of oxygen to biologically oxidise sulphite and bisulphite to sulphate to provide a sulphate stream (910).