Fabrication of cost-effective ceramic membranes with high gas permeance for gas/solid filtration under high temperatures

Silicon carbide (SiC) ceramic membranes with outstanding comprehensive properties offer an ideal solution for high-temperature gas/solid filtration. However, the preparation of SiC membranes involves multiple sintering steps at high temperatures. This makes the cost of preparation stay at a relatively higher level‌ that limits their further industrial applications. In this work, SiC particles with a mean size of 100 μm were used as support material and liquid sodium silicate (WG) was served as a sintering additive. Effects of the sintering additive contents and sintering temperatures on the properties of the ceramic supports were systematically investigated. In addition, the “green” bodies were prefilled by the polyvinyl butyral (PVB) solution to prevent the penetration of membrane layer particles. After drying, membrane layer dispersion was then coated on the “green” bodies using a tape-casting process to fabricate the membrane layer. The “green” membranes were finally co-sintered and the PVB was decomposed. The temperature matching properties of support and membrane layer was adjusted by using a reverse particle grading strategy, which effectively regulated the expansion rate of the membrane layer. The resulting membrane exhibited a membrane layer thickness of ∼70 μm and an average pore size of ∼2.6 μm with exceptional gas permeance of ∼212 m³·m⁻²·h⁻¹·kPa⁻¹. Additionally, the membrane demonstrated excellent thermal shock resistance at temperatures ranging from 25 °C to 800 °C. During high-temperature gas/solid filtration process (300 °C and dust particle size of ∼300 nm), these membranes obtained a remarkable dust removal efficiency of above 99.99 % and a low pressure drop of below 1.68 kPa.