Estimations of Gasifier Wall Temperature and Extent of Slag Penetration Using a Refractory Brick with Embedded Sensors

Abstract

The short service life of refractory lining in a slagging gasifier in the integrated gasification combined cycle results in low availability and high operating cost. For longer life of the refractory lining, estimation of slag penetration length and monitoring of wall temperature are important. In this paper, we have investigated two types of embedded sensors in the refractory lining of gasifier, namely, thermistor and interdigital capacitor, to estimate the wall temperature profile and extent of slag penetration. Conventional correlation-based approaches are not satisfactory for estimating outputs of interest from the raw sensor data for these systems because of high temperature gradient along the sensor as well as temporal change in the refractory properties due to slag penetration. Therefore, a thermal model of refractory brick, slag penetration model, and models of the embedded sensors are developed and used to estimate temperature and slag penetration profile by using linear and nonlinear estimators.