(568h) Condition Monitoring of a Gasifier in an Integrated Gasification Combined Cycle Plant

Sensors can be useful in the early detection of faults in the Integrated Gasification Combined Cycle (IGCC) system thereby preventing damage to life and property and ensuring efficient energy production. Fault such as refractory degradation in the gasifier cannot be measured directly with the current state of the art in measurement due to the extreme conditions within the gasifier. A sensor or a set of sensors can be placed at some other location so that it’s (their) response(s) can be used to monitor the condition of the refractory wall. A component-level model that is high-fidelity partial differential algebraic equation (PDAE)-based model is required for developing the quantitative model-based approach for sensor placement for component condition monitoring.

The gasifier is the heart of the IGCC power plant. Due to its operation at very high temperatures, the ash content in the coal melts to form slag. This slag gets deposited onto the gasifier wall and penetrates into the refractory bricks leading to refractory degradation. Traditionally, in modeling a slagging entrained flow gasifier, slag deposition is assumed to happen only when the char particle itself impacts the gasifier wall. However, it is reported that the ash content can melt while in the bulk phase itself. The slag formed can separate from the char particle due to the detachment forces in a process called shedding. These slag droplets can then themselves deposit onto the flowing slag layer on the gasifier wall. These processes are modeled by combining the continuum model of the gasifier and discrete particle model to account for the size and number of slag droplets. A comprehensive transport model is developed to calculate the flux of the slag droplets to the wall. This is required in order to model the flowing slag layer on the gasifier wall which in-turn will calculate the thickness of the slag layer and the temperature profile across it. Finally, slag penetration into the refractory and refractory degradation due to the mechanisms of tensile and compressive spalling is modeled. Using the PDAE based model and measurements from the gasifier, the sensor network will be able to estimate the condition of the refractory in real time.