脱塩器内部品のリスクベースメンテナンス方法にもとづく最適な保全周期設定の研究

Abstract

Maintenance planning of stationary equipment in the petroleum plant is based on information of maintenance inspection history, daily routine inspection history and operation monitoring trend recording, and level evaluation of likelihood of damage and degrees of influence of damage when damage occurs is performed using failure mode and effects analysis (FMEA) worksheet. Risk controls such as avoidance and removal, reduction, dispersion and tolerance are taken in accordance with the degrees of influence. While Electro-Dynamic Desalter (EDD) which is important to corrosion reduction of the atmospheric distillation unit is a pressure vessel, EDD is treated as electrical equipment since the internal structure in which 124 or more electrode plates are set has a function of agglomerating and removing fine water droplets which are impurities in crude oil by applied voltage 20-40kV.References concerning risk-based maintenance (RBM) for a large number of running EDD all over the world cannot be found. Damaged parts of EDD internals both in and outside Japan were sampled, and analysis in the viewpoint of failure physics, remaining life evaluation technology for non-metallic materials by a simple non-destructive testing method and knowledge of setting optimum maintenance period are obtained. The details are therefore described in this paper.