Thermal analyses of the lignite combustion in oxygen-enriched atmosphere

Abstract

In this work, the oxygen-enriched combustion behavior of indigenous lignite was measured by a thermogravimetric analyzer (TG). Combustion tests were carried out in N2/O2 atmosphere with an oxygen content ranging from 21% to 70 vol%.The data show that the calorific value per unit time (CVT) of the lignite was improved with increased oxygen concentration. In order to reveal the oxygen-enriched combustion process in detail, a new index of characteristic temperature Tc was defined to indicate the fixed carbon behavior during burning, and the combustibility indexes D?, Rw, and S were calculated to determine the combustion performance. The functional relation between CVT and oxygen concentration was determined by non-linear fitting method. The results indicated that the relationship between CVT and oxygen concentration fit the exponential function exactly.