Development of a biogas combustion CFD model for the analysis of trace emissions

Abstract

Biogas is emitted from landfills, anaerobic digesters, and many other biomass sources. Emitted biogas is usually burnt in order to reduce greenhouse effect and to get energy. Burning of biogas emits several pollutants, mainly CO 2 . Reducing the of emissions is very important in combustion. Emissions of combustion can be analysed experimentally or by computer simulations. Experiments are very accurate and expensive. Computer simulation is an economic way of analysing combustion systems. In this study emissions of biogas combustion are analysed with computer simulations. There are several methods of reducing emissions in combustion such as excess air control, air staging, fuel Staging, flue gas recirculation etc. In this study, the effect of excess air in biogas combustion is analysed. The range of optimum equivalent ratio was found as 0.85-1.1. Emitted gasses get dissipated in the atmosphere with the wind. The environmental effect from emissions of a 20kW industrial biogas burner in Colombo area was analysed using CFD simulations. Results show that the ground level is below environmental standard limits. , NO x and SO 2