Prediction for Pressure Drop across the Ceramic Tube Filter (CTF)

Abstract

he pressure drop across CTF (Ceramic Tube Filter) which is installed at Wakamatsu 71MW PFBC combined cycle power plant, is one of key parameters for both plant operation and performance. The pressure drop was attempted to predict, based on the data obtained with/without pre-cleaning cyclones installed at the upstream of CTF in Phasel and Phase2, respectively. The pressure drop consisted of two components of base line for filter itself and increasing ones with accumulated ash.
The base line pressure drop soon after pulse cleaning (ΔP_base) was estimated based on D'Arcy law using pre-measured L/K (thickness/permeability) values, while the rate of increasing pressure drop with accumulated ash between pulse cleaning interval (dΔP_c/dt) was estimated by Kozeny-Carman equation using ash analysis. Thus, the maximum pressure drop across filters was predicted successfully in both with/without pre-cleaning system from the respective linear correlation. The reason why ΔP_base was much higher without pre-cleaning system (Phase2) is discussed in terms of both characterization of permanent ash layer and behavior of fine ash in CTF during pulse cleaning.