Vapor-phase SMB adsorptive separation of linear/nonlinear paraffins

The separation of various mixtures of the C-5-C-6 paraffin fraction is considered, being an important stage of the process aimed to gasoline octane enhancement. The separation is carried out in a six-port vapor phase SMB pilot plant operated at 448 K and 350 kPa, using n-heptane as desorbent and 5A-zeolite as adsorbent. The experimental runs deal with the separation of both a binary mixture (70% isopentane and 30% n-pentane) and a multicomponent C-5-C-6 stream. The results of these experiments illustrate the role and the effect of the different operating parameters on the process performance and demonstrate the possibility of achieving high performance separation. Moreover, they nicely assess the reliability of the known criteria for selecting robust and optimal operating conditions for SMB units.