Pilot-scale experimental validation of unsaturated polyesters synthesis by reactive distillation

Reactive distillation (RD) is an integrated operation combining both reaction and separation, thus improving the productivity and selectivity, reducing the energy usage, eliminating the need for solvents and leading to intensified highly-efficient systems. In previous work, we performed the conceptual design and modeling of a reactive distillation process for synthesis of unsaturated polyesters. The simulation results of our previous work clearly demonstrated that reactive distillation is a promising alternative for the polyesters synthesis. This paper presents our pilot scale experimental validation work on the proposed RD process for polyester synthesis. Two configurations are investigated: (1) a RD column alone and (2) a RD column coupled with a pre-reactor. For the first configuration, we demonstrated that mostly monoesters are formed in the RD column, due to the short residence time at pilot scale. Since the combination of a RD column with pre-reactor allows sufficient residence time also at pilot scale, we demonstrated that polyesters are formed in the RD column. The extended rate-based model developed previously was used to simulate the pilot plant RD column. The model adequately predicts and describes the experimental data obtained from the pilot plant. Moreover, the product specification of the polyester produced in the continuous RD column was compared with the polyester product manufactured at industrial scale. Remarkably, it was found that the product specifications of the polyester produced in the RD column is comparable to that of the polyester produced in industry.