NOx Emission Modeling and Control in Bark Boilers

摘要

The emisison of NOx is of great concern to designers and operators of most industrial furnaces and boilers. Although the furl nitrogen content and the combustion temperature are not very high in the bark boilers used in pulp and paper mills. their emission of NOx may still surpass environmental limits if the combustion process is not managed correctly. It is therefore essential to understand the NOx formation process so that the NOx emission in bark boilrs can be cotnrolled. A NOx model, which includes the formation and destruction of both thermal NOx and fuel NOx, has been developed at the University of British Columbia in order to predict NOx emissions from bark boilers. The model sis validated here by comparison with experimental data form an operating bark boiler. As an application of the model, the NOx emission from this bark boiler is investigated, with several paraetric variations. The contribution of thermal NOx and fuel NOx, and the impact on NOx emissions of the bark fuel input, of fuel nitrogen content, and of the air distribution, are reported.