Patent ID: 7822583
Filing Date: 2010-10-26
Classification: B01D

Abstract:
1. A design method of batch falling strand devolatilizers comprising the steps of: constructing a database that contains data of batch falling strand devolatilizer vs. devolatilization of at least one kind of polymer and the database having information related to polymer viscosity, mass flow rate, number of recycles, stage efficiency and process efficiency; data of the number of recycles, the stage efficiency and the process efficiency in the database is substituted into a mass balance difference equation to get a backmixing parameter; when the backmixing parameter is zero or is approaching zero, a liquid diffusion stage efficiency equation having a film equation or a pool equation is integrated with the mass balance difference equation to get a devolatilization process efficiency equation; wherein the film equation is a stage efficiency times a square root of the viscosity and is equal to a constant C 1 times average exposure time of evaporation while the pool equation is a stage efficiency times a square root of the viscosity and is equal to a constant C 2 times average exposure time of evaporation and plus a constant B; and wherein the devolatilization process efficiency equation is written in this form: making a theoretical value of the process efficiency from calculation of the devolatilization process efficiency equation approach the value of the process efficiency by means of a theoretical value of the backmixing parameter; and substituting the theoretical value of the backmixing parameter into the devolatilization process efficiency equation for performing volume design of the batch falling strand devolatilizer.