Patent ID: 7429685
Filing Date: 2008-09-30
Classification: C10G

Abstract:
1. A process for isomerising paraffins in a feed comprising hydrocarbons containing 5 to 8 carbon atoms per molecule, characterized in that said feed is separated into at least two fractions, a fraction A mainly comprising hydrocarbons containing 5 or 6 carbon atoms, and a fraction B mainly comprising hydrocarbons containing 7 or 8 carbon atoms, and in which said fractions A and B are then separately treated under specific conditions in distinct isomerisation reaction zones wherein said reaction zones contain chemically different isomerisation catalysts in which the isomerisation activity of the catalyst treating fraction A is greater than the isomerising activity of the catalyst treating fraction B, in which at least one of the isomerisation reactions is carried out in the presence of an excess of hydrogen such that the ratio R of the number of moles of hydrogen to the number of moles of hydrocarbons leaving at least one reaction zone is in the range 0.06 to 0.3, and in which at least one of the isomerisation reactions is carried out in an excess of hydrogen such that the ratio R of the number of moles of hydrogen to the number of moles of hydrocarbons leaving at least one reaction zone is between 0.3 and 30.