C7 isomerisation with reactive distillation

Process for isomerising a hydrocarbon feed containing at least C7 hydrocarbons, comprising steps of

• a) in a separation column separating the feed into a heavy fraction comprising hydrocarbons having higher boiling point than n-heptane, an intermediate fraction being rich in n-heptane and/or mono-branched iso-heptanes and a light fraction being rich in multi-branched iso-heptanes;
• b) withdrawing continuously from the separation column a portion of the intermediate fraction being rich in n-heptane and/or mono-branched iso-heptanes;
• c) introducing the withdrawn portion into a isomerisation reactor and isomerising at isomerisation conditions the portion in presence of an isomerisation catalyst and a gas stream being rich in hydrogen;
• d) withdrawing from the isomerisation reactor an isomerisised effluent stream being enriched in multi-branched iso-heptanes together with cracked hydrocarbons and hydrogen;
• e) purging the cracked hydrocarbons and hydrogen from the isomerisised effluent to obtain a stabilised reactor effluent;
• f) recycling and introducing the stabilised reactor effluent into the separation column;
• and
• g) withdrawing from the separation column a top product being rich in multi-branched C7 isomers, wherein the stabilised reactor effluent in step (f) is introduced into the separation column at a level having a lower boiling point range than the boiling point range of the fraction being withdrawn from the separation column in step (b).