A Methodology for In-Situ Calibration of Steam Boiler Instrumentation

Abstract

This thesis presents a broadly useful diagnostic methodology to engineers and plant managers for finding the in-situ operating characteristics of power plant boilers when metered data is either missing or obviously erroneous. The methodology is able to analyze conflicting measurements and utilize analytic redundancy (AR) to deduce the measurement or measurements which are substantially in error without shutting down the plant and recalibrating all instrumentation. It is shown, through the case study power plant, that the methodology is quite robust in identifying faulty instruments in plants which possess a low degree of hardware redundancy. Once the malfunctioning meters are identified and the historical data are corrected, boiler characteristic curves can be generated to guide the daily operation and assist future implementation of on-line optimal load allocation. Finally, suggestions are given for the on-line diagnostics of instrument performance, as well as some operational guidelines useful to plant engineers for improved boiler operation.