Formação, controle e dispersão atmosférica dos Óxidos de Nitrogênio decorrentes da queima de bagaço em caldeiras industriais

Abstract

The principal sources of atmospheric polluting emissions of sugar/alcohol units are the steam boilers that use sugar cane bagasse as fuel. As a result of the combustion their release carbon oxides, (CO and CO2), nitrogen oxides (NOx) and particulate matter. By using an atmospheric polluting dispersion study, this work aims at determining the impact of the emission of nitrogen oxides released by a Sugar and Alcohol Plant on the quality of the air in the surrounding area. The case of Barra Grande Plant located in the state of São Paulo, Brazil, will be studied. The formation and control mechanisms are assessed based on the measurements of the NOx concentrations in the combustion products. The atmospheric dispersion study was carried out by using the ISCST3 (Industrial Source Complex Short Term version 3) dispersion model, recommended by USEPA (United States Environmental Protection Agency), based on hour meteorological data of the place within the period of 2002. Two types of analyses regarding the quantity of NOx present in the atmosphere will be shown. The first one considers the total conversion of NOx into NO2 as it is recommended by most environmental agencies. In this case, the use of technologies aiming at the control and prevention of NOx emissions could be necessary. In turn, the second analysis considers the Janssen Factor, which describe the conversion of NOx into NO2 and NO, considering the local atmospheric characteristics and the ozone concentration (O3), approach that was defined as the most realistic one in this work. The results of the dispersion study are presented as NOx iso-concentration curves, based on which the conclusions about the appropriate control and prevention technologies are drawn.