(465a) CFD Simulation of a Fluidized Bed Gasifier Operating with Lignite Coal

Declining supplies of crude oil in combination with increased environmental pressure to reduce greenhouse gas emissions from coal-fired power plants has led to renewed interest in gasification as a clean coal technology. The focus of the current study is lignite coal, also known as brown coal, which exists in significant quantities throughout the world. Fluidized bed gasification is at the forefront of technologies being developed for advanced power generation cycles and polygeneration of fuels and chemicals using coal resources. Fluidized beds are well-suited for lignite coal because the lignite exhibits high reactivity at the relatively lower fluidized bed gasification temperatures. However, lignite coal also presents substantial challenges to fluidized bed technology on account of its high ash, moisture, and trace mineral contents. In conformity with growing attention toward lignite coal, different aspects of lignite gasification should also be investigated. The collection of this information can aid in the design and installation of future full scale lignite gasifiers. Computational Fluid Dynamics (CFD) modeling has gained widespread interest as a complementary tool to experimental studies for pulverized coal gasification, but mainly for bituminous coals. In the present work, CFD simulation of fluidized bed lignite coal gasification has been considered. Detailed descriptions of the flow patterns inside the gasifier as well as effect of different operating parameters on the gasifier's performance will be provided. A particular focus of this work will be the realization of reduced computational time through the use of advanced computing power and novel numerical algorithms in conjunction with researchers in the Department of Computer Science.