(19)

(11)

EP 1 549 419 A1

(12)

(43) Date of publication: 06.07.2005 Bulletin 2005/27 (21) Application number: 03751012.0 (22) Date of filing: 01.10.2003

(51) International Patent Classification (IPC)7: B01D 53/94, F01N 3/08 (86) International application number: PCT/GB2003/004290 (87) International publication number: WO 2004/030798 (15.04.2004 Gazette 2004/16)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR (30) Priority: 05.10.2002 GB 0223126 19.03.2003 GB 0306264 (71) Applicant: JOHNSON MATTHEY PUBLIC LIMITED COMPANY London SW1Y 5BQ (GB)	(72) Inventor: TWIGG, Martyn, Vincent Cambridge CB3 8PQ (GB) (74) Representative: Nunn, Andrew Dominic et al Johnson Matthey Technology Centre,Blount's Court,Sonning Common Reading RG4 9NH Reading RG4 9NH (GB)