New trends in the improvement of cyclones

Abstract

This article examines the possibilities of reducing catalyst attrition and cyclone wall erosion through optimization of the aerodynamic conditions in the cyclone. It is assumed that the disintegration of catalyst particles and erosion of the cyclone walls take place at exactly the same points (e.g. the seats of erosion in the cyclones can serve as natural indicators in determining the zones of catalyst pulverization). In catalytic cracking units, internal cyclones are used as the primary means of cleanup of the gas for process purposes. Cyclones trap out 99.8-99.95% of the catalyst entrained from the fluidized bed by the contact gas. The retrofitting of standard cyclones with chambers for preliminary aerodynamic stabilization of the flow yielded favorable results. The results of erosion tests on type TsN cyclones with and without a stabilization chamber indicate that the proposed stabilization method can give an approximately fivefold reduction of erosion of the cylindrical part of the cyclone. An important advantage of cyclones with added stabilization is the increased efficiency of dust collection. It is concluded that supplementary aerodynamic stabilization of the dust-laded gas flow and reduction of the angle of attack can give substantial improvements in the operating characteristics of cyclones, both cylindrical and more » spiral-conical. « less