Gas cleaning at high temperatures cake formation Filtration mechanical prop chemical resistance Cake detachment geometry fracture mechani novel geometries filter surface modification <Combinations of cyclone filter (Combinations of physical chemical separators Figure 4. Research issues in the development of ceramic filters for hot gases [141 Table 2 Academic issues in ceramic filter research [141 Fluid mechanics Particle mechanics Filtration flow field distribution cake formation Cleaning pulse propagation cake detachment What is the effect of the challenging dust, in relation to the operating temperature. on the operating pressure drop? Is the filter medium suitable in relation to the particle size distribution of the challenging dust and system operating conditions? How can the energy requirement for cleaning be minimized? What are the optimum layout and geometry of the filter vessel? Industrially, these issues are being investigated through the use of pilot plants and advanced power generation demonstration plants, e. g. the 71 Mw(th) PFBC demonstration plant at Wakamatsu, Japan and the 15 MW(e)hybrid demonstration plants in Wilsonville, USA. Additionally, controlled pilot-scale investigations have been conducted. However, the majority of industrial knowledge(for both power and non-power generation applications) is gained from plant operating experience rather than a prior fundamental understanding of the principles involved. At present, the most pressing issue in industrial applications concerns the mechanical strength and chemical resistance of the filter medium in relation to its operating environmentGas cleaning at high temperatures 663 Figure 4. Research issues in the development of ceramic lters for hot gases [14]. Table 2. Academic issues in ceramic lter research [14] Fluid mechanics Particle mechanics Filtration ow eld distribution cake formation Cleaning pulse propagation cake detachment ² What is the effect of the challenging dust, in relation to the operating temperature, on the operating pressure drop? ² Is the lter medium suitable in relation to the particle size distribution of the challenging dust and system operating conditions? ² How can the energy requirement for cleaning be minimized? ² What are the optimum layout and geometry of the lter vessel? Industrially, these issues are being investigated through the use of pilot plants and advanced power generation demonstration plants, e.g. the 71 MW(th) PFBC demonstration plant at Wakamatsu, Japan and the 15 MW(e) ‘hybrid’ demonstration plants in Wilsonville, USA. Additionally, controlled pilot-scale investigations have been conducted. However, the majority of industrial knowledge (for both power and non-power generation applications) is gained from plant operating experience rather than a prior fundamental understanding of the principles involved. At present, the most pressing issue in industrial applications concerns the mechanical strength and chemical resistance of the lter medium in relation to its operating environment.