Biomass furnace for externally fired gas turbine: Development and validation of the numerical model
Abstract Externally fired gas turbines (EFGT) are currently being investigated for co generation from biomass, because of their ability to deal with low grade fuels without the complexity of gasification. Main drawbacks of the technology are related to the high thermal stresses experienced by the heat exchanger. The present work proposes a computational fluid dynamics (CFD) analysis of a grate fired furnace installed in a EFGT cycle, with the purpose to provide a tool for detecting the most critical regions in the furnace. The model is complemented with a process simulation of the entire EFGT cycle. Different approaches for treating the fuel bed and their impact on the CFD analysis are discussed and validated through the availability of in flame measurements of temperature and chemical species. Predictions indicate the need for a detailed fluid dynamic characterization of the grate region, which was found to largely impact the furnace flow and thermo chemical fields.