Technology Type

There are two groups of Technologies for the recovery of Cyclopentadiene (CPD), namely the Thermal Methods and the Extractive Distillation Methods, eventually combined with thermal operations. The Thermal Method is based on the reversible Dimerization of CPD. It consists essentially in the single-stage conversion of the CPD content in the Cs fraction (or in the Benzene Distillation forerun) into DCPD by Thermal Dimerization. The boiling point of DCPD being 170°C, it is readily separated by Distillation from the other, lower-boiling Components of the Cs Fraction. The Thermal Treatment is carried out at 80 to 120 °C for 2 to 7 hours at a slightly increased pressure (at the vapour pressure of the Hydrocarbons, for the given temperature). The DCPD obtained has a purity of 90 to 93%, its impurities consisting of Co-Dimers formed with other Dienes of the Cs fraction. CPD is recovered from DCPD by liquid-phase or vapour-phase Depolymerization. Purity of DCPD and hence of CPD can be improved up to 95 to 96% by repeated Dimerization, subsequent Rectification and Depolymerization.