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The fabric filtration process is divided into three stages, i.e. depth filtration, transition filtration and surface filtration. A new model is proposed to describe the three stages under both virgin and regeneration conditions. The concept of an interface dust layer is introduced to predict the transition from the depth filtration stage to the transition filtration stage. The transition filtration stage due to the non-uniform accumulation of residual dust on a filter is characterized by two parameters — the surface cleaning fraction, f, and the residual dust load on the uncleaned surface, Wu0. It is found that f decreases and Wu0 increases with the number of filtration cycles. This result suggests that both the fraction of uncleaned surface and the thickness of dust cake on the uncleaned surface increase with the number of filtration cycles. The present model successfully describes the change in pressure drop during the filtration cycles using the parameters. [ABSTRACT FROM AUTHOR]

The VDI type 1 rig and JIS rig are two of the major testing rigs for cleanable fabric filters. We measured the filter performance using these rigs and compared the results in order to characterize the two testing rigs. The filter performance tests showed that the filter cleaning efficiency measured with the VDI type 1 rig is higher than that with the JIS rig. The difference in cleaning efficiency led to the different residual pressure drop after the aging of the filter. The difference in filter performance measured by the two rigs can be minimized by modifying the aging condition, i.e. either reducing the number of filtration cycles during the aging with the JIS rig or increasing it with the VDI type 1 rig so as to give the same residual pressure drop after aging. Furthermore, it is found that there is an optimum filtration cycle time to grow the residual pressure drop during the filter aging in order to minimize the time period of filter aging. [ABSTRACT FROM AUTHOR]