Coal combustion modeling: A comparative study

Abstract

Coal combustion is a major power source in the world, and energy conservation and environmental protection are now the top priorities in terms of carrying out the strategy for continuous and persistent development in power generation. The intricate coal combustion process must be investigated to present the process inside a live boiler as accurately as possible. In this study, the ANSYS FLUENT program is used to compare two species models namely, species transport (STM) and nonpremixed model (NPM). The two models are run with similar geometry and boundary conditions. It was found that the STM enables entering of the species reactions and activates a selection for the crucial coal combustion and devolatization processes. The NPM combustion process takes place with the assumption that combustion is in equilibrium, a Probability Density Function (PDF) mixture table is calculated first before the simulation can be run. Both submodels can depict the combustion process for a CFPP boiler providing temperature gradients within the boiler with species composition throughout the boiler. The NPM does not track species individually through the boiler, limiting model validation data. The STM was found to be suitable since it provided more comprehensive coal combustion results, that can be used for model validation.