On the production of defect free honeycomb extrudate

[摘要] MAST Carbon are scaling up production of activated carbon honeycomb monoliths, to which there are two major barriers. Firstly the extrusion process suffered from an unacceptably high rejection rate (around 50%) of monoliths due to malformation of channels and tearing at the surface and interior of the structure. Pastes were characterised using the Benbow Bridgwater paste flow model and it was shown that the parameters of this model could be controlled by the careful addition of various extrusion aids to the formulation. It has also been shown that the extrusion profile can be predicted from the extrusion die geometry and the Benbow Bridgwater parameters. These discoveries led to a new paste formulation, specifically designed to produce defect free monoliths with MAST Carbon’s extrusion dies, reducing the rate of monolith rejection to zero. Secondly, the monoliths required 10 days to dry at ambient conditions; a serious bottleneck in the production process. A forced drying regime was introduced which reduced the drying time to less than 24 hours without causing any internal cracks. A model describing the drying and shrinkage behaviour of the monoliths was developed and used to predict the shape of the stress field in the monolith.

[发布机构] University:University of Birmingham;Department:School of Chemical Engineering

[关键词] Q Science;QC Physics