Evaluation of hot coating method to make the composite ceramic membran
Subject Areas :شهرام قنبری پاکدهی 1 , الهام رحیمی 2 , کوروش شفیعی 3
1 - دانشیار مهندسی شیمی، مجتمع شیمی و مهندسی شیمی، دانشگاه صنعتی مالک اشتر
2 - دانشجوی دکترا، مجتمع شیمی و مهندسی شیمی، دانشگاه صنعتی مالک اشتر
3 - استادیار مهندسی شیمی، مجتمع شیمی و مهندسی شیمی، دانشگاه صنعتی مالک اشتر
Keywords: Silica, Ceramic membrane, Hot coating, Gas permeability,
Abstract :
The use of membrane has very specific role in the separation processes such as gas separation and dehydration of the azeotropic feed. The most important step in any membrane process is selection of the membrane material and its fabrication. The ceramic membrane has been more attracted due to sufficient strength, thermal, and chemical stabilities. The ceramic membrane is a composite membrane containing three layers. The first layer is a macroporous support, the second layer is a mesoporous support, and the third layer is silica with micropores which plays a key role in the separation process. Therefore, the quality and uniformity of the third layer is so important that increases directly the efficiency of the separation process. In this article, a method has been presented in which the defects of silica are reduced. In this method, known as hot-coating, the support was heated before all usual coating. Reduction in gaps or defects and increase in continuity or uniformity of the silica layer was observed from SEM analysis. On the other hand, comparing the results of gas permeability test through hot coating and usual coting revealed that the exit gas flow rate was reduced significantly in hot coating. According to reduction in thickness of the silica layer, the decrease in exit gas flux is attributed to increase in continuity and reduce in defects of the layer. So, the continuous or uniform silica layer is obtainable via hot coating through fewer coating steps than usual coating