279163 Analysis of Fuel NOx Formation in an Industrial Burner Using Biomass Derived Producer-Gas

Thursday, November 1, 2012: 9:50 AM
316 (Convention Center )
Sujith Sukumaran and Song-Charng Kong, Mechanical Engineering, Iowa State University, Ames, IA

Biomass-derived producer gas is a potential fuel that can be used for heating applications. It is produced by gasification of biomass. However, it has been observed that biomass gasification can result in traces of ammonia in the producer gas, which causes high fuel NOx emissions after combustion. Current industrial burners, which are developed for natural gas and coal syngas, are not designed to mitigate fuel NOx emissions from producer gas combustion. In this study, the reaction pathways of ammonia in producer gas combustion and NOx emission characteristics are studied under different conditions using detailed chemical kinetics mechanism. A reduced form of the reaction mechanism is then used with a 3-D CFD code to model the producer gas combustion in an industrial burner. The modeling results are compared with the experimental data and good levels of agreement are obtained. To further analyze the NOx formation regions inside the burner, the NOx formation rates in the combustion zone are analyzed together with the local equivalence ratio and temperature. It is found that in producer gas combustion NOx production is favored by high temperature zones and low equivalence ratio. Thus, by proper controls of temperature and equivalence ratio of the combustion zone, NOx emissions from producer gas combustion can be mitigated.

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