| Based on the low energy consumption, low cost and highefficiency, the falling strand devolatilizer (FSD) experiment device wasdesigned in this paper. Firstly, it introduced a method of determination ofresidual acrrylonitrile in polyacrylonitrile solution by headspace gaschromatography and at the same time, the effects of content of polymer insolution, equilibrium time, equilibrium temperature and headspacesample volume on the determination results were analyzed. Through theimprovement of optimization conditions, solving the problem of big errorof traditional measuring method in industry. Secondly, the hydrodynamicsperformance of hole elements has been investigated. PAN/DMSOsolutions with viscosity range from 2.150~236 Pa.s were selected asexperimental media. The performance on fluid flowing, film forming, andsurface renewal of single element, which changed with the viscosity,operation conditions and diameter, has been studied by using visualtechnique. Thirdly, The influence of the liquid viscosity, temperature,vacuum degree, and initial AN content in the liquid on AN removalefficiency was investigated. The experimental results indicated that the removal efficiency increased with increasing vacuum degree andtemperature and decreased with increasing liquid viscosity. It was alsoobserved that AN removal efficiency isn't related to the initial AN contentdirectly. Finally,A mass transfer model for devolatilization process of highlyviscous media in falling strand devolatilizer (FSD) was developed basedon penetration theory and mass conservation. It was found that bubblingplayed an important role in the devolatilization and nitrogen had thelargest effect on the polymer-solvent behavior, then on the basis ofexperiment, the correlation of removal efficiency of AN in PAN—DMSOviscous solution was proposed. The relative error between predicted andexperimental data was within the range of 4 % for efficiency ofacrylonitrile removal . |
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