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(11)

EP 1 481 037 A1

(12)

(43) Date of publication: 01.12.2004 Bulletin 2004/49 (21) Application number: 03711432.9 (22) Date of filing: 05.03.2003

(51) International Patent Classification (IPC)7: C10G 45/02 (86) International application number: PCT/US2003/006821 (87) International publication number: WO 2003/076552 (18.09.2003 Gazette 2003/38)

(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 Designated Extension States: AL LT LV MK (30) Priority: 06.03.2002 US 93567 (71) Applicant: BP Corporation North America Inc. Warrenville, IL 60555 (US)	(72) Inventors: HOEKSTRA, George, R. Wheaton, IL 60187 (US) KRUSE, Larry, W. Donnellson, IA 52625 (US) (74) Representative: Ritter, Stephen David et al Mathys & Squire100 Gray's Inn Road London WC1X 8AL London WC1X 8AL (GB)