(19)

(11)

EP 0 819 159 A1

(12)

(43) Date of publication: 21.01.1998 Bulletin 1998/04 (21) Application number: 96907589.0 (22) Date of filing: 21.03.1996

(51) International Patent Classification (IPC):  C10M 161/ 00( . ) C10M 169/ 04( . ) (86) International application number: PCT/GB1996/000663 (87) International publication number: WO 1996/029382 (26.09.1996 Gazette 1996/43)

(84) Designated Contracting States: BE FR GB NL (30) Priority: 23.03.1995 GB 19950005938 (71) Applicant: EXXON RESEARCH AND ENGINEERING COMPANY Florham Park, New Jersey 07932-0390 (US)	(72) Inventors: GRAHAM, John, Kenneth, Esso Petroleum Company Ltd. Abingdon, Oxfordshire OX13 6AE (GB) AIKEN, Alison, Jane, Esso Petroleum Company Ltd. Abingdon, Oxfordshire OX13 6AE (GB) (74) Representative: Fletcher Watts, Susan J., et al  ESSO Engineering (Europe) Limited, Patents and Licences, Mailpoint 72, Esso House, Ermyn Way Leatherhead, Surrey KT22 8XE Leatherhead, Surrey KT22 8XE (GB)