Development of a high-performance cake-less continuous filtration system

Abstract

A new cake-less continuous filtration system with a rotating disk filter and slurry prepared in a well-dispersed state is discussed in this paper. It is expected that the new system can concentrate a feed suspension much more than traditional filtration systems and that the concentrate can be discharged by the filtration pressure without a scraping device. We tried to filter some difficult to filter materials such as sericite, hydrolyzed cellulose, pulp wastewater and algal suspension. Concentrated slurries of sericite and hydrolyzed cellulose were discharged at the 35 vol% and 12 mass%, respectively. The algal suspension and the pulp wastewater were concentrated up to 8 times more than the concentration of feed suspensions. The concentrates of every sample retained fluidity and flowed out of the new system by way of the filtration pressure. In this system, it was shown that the filtration flux increased with the rotation speed. At lower rotation speeds, the filtration flux was independent of pressure. Conversely at higher rotation speeds, the filtration flux increased along with the pressure. This dependency was clearer in the case of the large disk than when the small disk was used. We also proposed a model for a sweeping mechanism in this system which is explained in the above results.