A NOVEL HOT GAS FILTER UNIT THROUGH CERAMICS SUPPORTS AND MEMBRANES

摘要

Hot gas ceramic filters for PFBC power coal units For that very severe conditions, the ceramic candle body has been chosen with a high porosity and a pore size near 25 μ. This ceramic body is protected by a membrane with a thickness of 100 μ and with a composition such as alumina and TiO_2 which resist the best to chemical attack. Pore size of membrane is less than 5 μ. Such a ceramic body with a thin selective membrane gives a low ΔP, To keep the best performance of the filter, the temperature must not exceed 750°C. 1. Cordierite candle gives the best filtration efficiency / cost ratio. 2. SiC candle has a higher mechanical strength but its cost is higher too. A test on the first small prototype has been conducted at room temperature. Efficiency, permeability and ΔP on SiC and Cordierite were better than expected by computerizing. Hundreds of candles with a membrane coating have been manufactured for a pre-industrial test.