Predicting the pressure drop across hot gas filter (CTF) installed in a commercial size PFBC system

The 71 MWe PFBC combined cycle power plant at Wakamatsu, Electric Power Dev elopment Company (EPDC) (funded by the Ministry of International Trade and Industry (MITI) and the Center of Coal Utilization Japan (CCUJ)) achieved 1 1,500 h accumulative operation while establishing extremely low dust emissi on (< 1 mg/m(3) N) with a hot gas cleaning system combining cyclones and ce ramic tube filter (CTF). Two different configurations of cyclones and CTF w ere examined in Phases 1 and 2, where several coals and domestic limestone as absorbents were used. The pressure drop across the filter (<Delta>Pc) was continuously observed t o predict its maximum value (DeltaP(max)) under operating conditions. The D eltaP(max) value consisted of irreversible (DeltaP(base)) and reversible (D eltaP(base)) drops with cleaning as the following equation shows, DeltaP(max) DeltaP(base) + DeltaP(own) = f(face velocity, gas viscosity, th ickness/permeability, dust concentration) + d Delta Pc/dt x t where: d Delta Pc/dt, mean rate of Delta Pc increase during cleaning interv al; t, reverse cleaning interval time. The pressure drop across the regenerator (DeltaP(regenerator)) was monitore d to calculate the changing face velocity of each compartment according to the Fanning equation. Both pressure drops (DeltaP(base) and DeltaP(own)) we re successfully estimated by the face velocity calculated for both phases. Dust concentration to the filter in both phases was found to improve the pr edictability of the base line one (DeltaP(base)). The conditioned filter material was proven to be stable, showing a constant drop depending on the operating condition. The particle size of ashes on t he filter must be considered in order to obtain better prediction of the ma ximum pressure drop in the future. (C) 2001 Elsevier Science B.V. All right s reserved.