Material characterization and analysis for selection of refractories used in black liquor gasification

Black liquor gasification provides the pulp and paper industry with a technology which could potentially replace recovery boilers with equipment that could reduce emissions and, if used in a combined cycle system, increase the power production of the mill allowing it to be a net exporter of electrical power. In addition, rather than burning the syngas produced in a gasifier, this syngas could be used to produce higher value chemicals or fuels. However, problems with structural materials such as the refractory lining of the reactor vessel have caused unplanned shutdowns and resulted in component replacement much sooner than originally planned. Through examination of exposed materials, laboratory corrosion tests and cooperative efforts with refractory manufacturers, many refractory materials issues in high-temperature black liquor gasification have been addressed and optimized materials have been selected for this application. In this paper, an updated summary of the characterization and analysis techniques used for refractory screening and selection will be discussed along with characteristic results from these methods which have led to the selection of optimized materials for both the hot-face and back-up linings used in this application.