Efficient construction of tubular mullite fiber membrane filter with high gas permeance for gas/solid filtration

Ceramic filter membranes exhibit great potential in industrial hot gas filtration. However, it was limited by its low gas permeance due to the low porosity and high transfer resistance. In this work, novel filter-pressing method was employed to fabricate fibrous ceramic fiber membrane tubes (FCFMTs) by using mullite fibers, glass fibers and silica sol. The silica sol and glass fibers were used as composite sintering aids to enhance the mechanical strength at a relatively lower sintering temperature. In addition, the freeze drying method was investigated in detail to guarantee the uniformity of silica sol in the matrix of the FCFMTs. It was demonstrated when the addition content of the silica sol and glass fibers were 40 vol% and 30 wt%, respectively, the sintering temperature was 1200 °C, the FCFMTs obtained a mean pore size of 35 μm and gas permeance of 787 m³m^-2h^-1KPa⁻¹, respectively. The fly ash particles recycled from the electrical plant were employed as model dust in the dust-laden gas. The resulting FCFMTs also exhibited high particle rejection behavior towards dust-laden gas with rejection rate of above 99.9 %. The pressure drop and the outlet dust concentration were below 2 kPa and 0.1 mgm⁻³, respectively after three filtration-cleaning cycles. This work provides an important reference for high-performance ceramic filter for the cleaning or filtration of dust-laden gas.