New Reactor for Polyester Polyols Continuous Synthetic Process

Abstract

Summary Based on the kinetic and thermodynamic equations, a comprehensive mathematical model for the continuous synthetic process of polyester polyols was developed, which was carried out in two innovational bubbling reactive distillation towers (BRDTs). In this new type of reactor, condensation reactions among oligomers of polyester polyols were accomplished efficiently and rapidly. Two bench BRDTs with the height of 2 m were applied for the continuous process of poly(ethylene adipate) (PEA). In the first continuous esterification operation at atmospheric pressure, linear oligomers were discharged from the bottom of the column, while water and ethylene glycol (EG) passed a few column trays and a packing section and reached the top of the column. Then water was discharged as byproducts and EG was sent back to the first tray for further reaction. In the second continuous polycondensation operated in the second BRDT under partial vacuum, PEA was discharged from the bottom of the column, while water and ethylene glycol passed a few column trays, they were discharged as byproducts. The influence of major operating conditions on reactor performance was also simulated. Simulation results provided a strategy for developing and optimizing this process.

Process Intensification of the Synthesis of Biomass-Derived Renewable Polyesters: Reactive Distillation and Divided Wall Column Polyesterification

“…This configuration consists of three nested loops of mixers and flashes where the solution of the process is achieved through the selection of only two streams that will lead to the evaluation of all the existent recycles. , Our proposed RD model and consequently DW model are inspired by the simulation methodology presented by Doherty and Malone and their model assumptions: adiabatic conditions; the heat of reaction is negligible if compared to the heat of vaporization; the reaction takes place in the liquid phase only; total condenser and each stage is considered a perfectly mixed stirred tank reactor (CSTR). Similar RD simulation models to our work include the mathematical model proposed by Chen et al where the authors consider each column tray as a perfectly mixed reactor due to the backmixing and bubbling effect of the water and the diol present.…”

“…The M n and DPN obtained were nevertheless in the same range of those reported for other polyesterification systems in reactive distillation, such as maleic anhydride and propylene glycol2800 Da 46 and poly(ethylene adipate)1500−2500 Da. 48 The segments' profiles are available in Supporting Information sections 5 and 6. 5.3.…”

“…47 Moreover, the modeling of the production of poly(ethylene adipate) was carried out considering two bubbling reactive distillation towers. 48 The effect of operating conditions such as residence time, reaction pressure, feed ratio, and temperature were analyzed. Several more simulation works have been reported for esterification problems.…”

“…The authors reported the operating conditions and final product specifications and later validated the model against pilot scale data with two different configurations: A single RD column and a column coupled with a prereactor, achieving conversions of 37% and 90%, respectively . Moreover, the modeling of the production of poly­(ethylene adipate) was carried out considering two bubbling reactive distillation towers . The effect of operating conditions such as residence time, reaction pressure, feed ratio, and temperature were analyzed.…”

Method of purification of post-production condensates from polyester polyol production

“…Particles of substrate -glycols are collected together with the released water. The effect of entrainment of glycols with the water condensate is increased by means of vacuum and the fl ow of an inert gas stream, commonly nitrogen 5 . Diethylene glycol is one of the typically used bifunctional alcohols in the production of polyester polyols 6 .…”