Gasifier Health Monitoring using Smart Refractory Bricks

The short life of the refractory lining in the slagging gasifier is a major concern leading to high operating cost and low availability. For prolonging the life of the refractory lining, it is important to monitor its health. Two key variables for monitoring the health of the gasifier refractory are the temperature profile both in the axial and radial directions along the wall and the extent of slag penetration in the wall. However, stateof- the-art measurement techniques are inadequate for the harsh gasifier environment. In this paper, a novel approach is considered where sensors embedded in a brick, denoted as the smart refractory brick, is used to estimate these two variables. Typical approaches, where correlations between the raw measurements (such as the voltage, current, etc.) and the variables of interest (such as the temperature) are used, are inadequate due to the high spatial temperature gradient along the wall and time-varying material properties. In this paper, a model-based estimation approach is developed to address this issue. Issues with the out-of-sequence measurements in the estimation framework are addressed.