CFD-modelling of selective non-catalytic reduction of NOx in grate-kiln plants

LKAB (Luossavaara-Kiirunavaara AB) is an international company that produces iron ore products for the steel industry, their main product is iron ore pellets. The overall goal of this project is to find out if selective non-catalytic reduction (SNCR) technologies can be used in grate-kiln plants for NOx reduction. The technique has, to the best knowledge of the author, never been used in this context before despite that it is commonly used in cement and waste incineration plants. A CFD model of parts of a real grate was created and numerical simulations with the commercial code ANSYS CFX11 was carried out solving the flow field. A model for spray injection into the grate was then included in the model enabling a study of the overall mixing between the injected reagent droplets and the NOx polluted air. The simulations show promising results for SNCR with urea but not with ammonia.Validerat; 20101217 (root)