Simulation of NOx formation in glass melting furnaces by an integrated computational approach: CFD+Reactor Network Analysis

摘要

A procedure, called Reactor Network Analysis, has been developed for the prediction of NOx emissions by practical combustion systems. It is a postprocessor of a CFD simulation which allows to extract from CFD 3D fields an "equivalent" network of reactos, for which it is possible to use a detailed reaction kinetics. The study of two glass melting furnaces, drawn from the experience of the authors, are presented to illustrate the methodology. The furnaces were experimentally characterised, then CFD simulations were performed, setting carefully the boundary conditions for the radiative heat exchange, and adopting a simplified reaction kinetic scheme with 9 species and 10 reactions, for the chemistry. Then, from each CFD simulation, a chemical reactor network was extracted, as simplified flow model, to perform the computation of the secondary product combustion species by means of a complex kinetics mechanism. An evaluation of the models was given comparing the measurements with of both the temperature CFD field and the NOx prediction by Reactor Network Analysis. Finally, an estimate of the effect of some NOx reducing techniques was given, changing some key parameter of the reactors model.