A Practical Computational Model To Estimate PAH Emission From Furnaces

Abstract

Due to the large computational overhead associated with simulating the PAH chemistry, predicting the PAH emission from industrial furnaces based on detailed CFD simulations is impractical. To address the lack of tools for practical estimation of PAH emissions from furnaces, a novel approach based on CFD + 0D perfectly stirred reactor (PSR) to predict PAH generation rate is proposed in this work. This approach uses the results of the CFD simulation of the reactive flow of major process gases, based on a reaction mechanism, as the input to 0D PSR reactors (which is run on each cell in the domain) using detailed PAH chemistry.The model is used to simulate various operationally relevant scenarios like variations in the inflow (composition and velocity) of gases emanating from the charge surface and flue gas recycling levels. The model is seen to be able to capture the overall trends in the PAH emission predicted by the detailed reaction mechanism based CFD for cases simulated. As the PAH emission is chemistry driven, the choice of reaction mechanism used to CFD simulation of the major species in the proposed approach is seen to be critical as it provides a distribution of reaction intermediates relevant for PAH chemistry.