Mathematical Modeling and Experimental Study of Biomass Combustion in a Thermal 108 MW Grate-Fired Boiler

Abstract

Grate boilers are widely used to fire biomass for heat and power production. However, grate-firing systems are often reported to have relatively high unburnout, low efficiency, and high emissions and need to be optimized and modernized. This paper presents the efforts toward a reliable baseline computational fluid dynamics (CFD) model for an industrial biomass-fired grate boiler, which can be used for diagnosis and optimization of the grate boiler as well as the design of new grate boilers. First, on the basis of the design conditions, a thorough sensitivity analysis is done to evaluate the relative importance of different factors in CFD analysis of the grate boiler. In a late stage, a two-day measuring campaign is carried out to measure the gas temperatures and the gas concentrations in the boiler using a fiber optic probe connected to a Fourier transform infrared spectrometer. A baseline model is then defined on the basis of the sensitivity analysis and the measurements. The baseline results show an ove...