Redução das emissões de NOx na clinquerização pela utilização das técnicas de requeima e combustão estagiada

Abstract

Pollutant emission issues are growing, and more strict emission controls laws are being reinforced. In this scenario, nitrogen oxide (NOx) emission abatement is presenting itself as a major challenge, as these components cause acidic rain and photochemical smog, also affecting human health and the environment in many ways. This work aims to implement mechanisms to reduce NOx emissions in the clinkerization process, the heart of the cement manufacture in an existing and operating cement plant, by the employment of reburn and staged combustion techniques, chosen due to their low cost and high effectiveness on NOx emission reduction. Computational Fluid Dynamics (MI-CFD) is used to analyze flow profiles inside the calciner and to anticipate the results obtained after operational and structural modifications, allowing to reduce the number of tests based on trial and error when repositioning the combustors in the vessel. CFD was done by Cinar Ltd (Souza, 2017) and the optimization work was result of the joint effort of both Cinar and the Client. The calciner in this study is an in-line type, and three modifications were simulated and analyzed. A modification is to be chosen and implemented, apply reburn and staged combustion, in order to mitigate NOx generation. From the inspection of the work outcomes, the choice of reburning and staged combustion techniques to abate NOx seems has shown to be accurate, as the plant was able to reduce NOx emissions in about 40% from the baseline.