專利摘要：
A design method of batch falling strand devolatilizers is disclosed. The method includes following steps. Firstly, construct a database that contains data of batch falling strand devolatilizer vs. devolatilization of at least one kind of polymer. Then data 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. By optimizing of a theoretical value of the backmixing parameter, a theoretical value of the process efficiency from calculation of the devolatilization process efficiency equation approaches the value of the process efficiency. Then the theoretical value of the backmixing parameter is substituted into the devolatilization process efficiency equation for performing volume design of the batch falling strand devolatilizer.