Effects of CaO‐K 2 CO 3 on combustion behavior and emission properties of SO 2 and NO X during coal sludge combustion

The purpose of this work is to investigate the effect of CaO‐K 2 CO 3 on the coal sludge combustion and the emission properties of SO 2 and NO X . The combustion characteristics of coal sludge with or without catalysts were studied in a thermogravimetric analyzer, and the experiments were conducted from the ambient temperature to 1000 °C at a heating rate of 10 °C min −1 . Ignition index, burnout index, and general combustion parameter had been put forward to describe further the combustion characteristics of coal sludge. Combustion experiments were carried out in a quartz tubular fixed‐bed reactor, and the NO x and SO 2 released during combustion were monitored continuously using a flue gas analyzer. The results show that adding K 2 CO 3 accelerates the release of volatile matter and the combustion of partial fixed carbon. The reduction of ignition temperatures and burnout temperature followed the increase of the concentration of K 2 CO 3 . When the coal sludge is loaded with CaO and 1% K 2 CO 3 , the general combustion parameter is the maximum, and the activation energy (E) is the smallest. Meanwhile, when the coal sludge is loaded with CaO and 1% K 2 CO 3 , it emits less SO 2 and NO X . Therefore, it is concluded that CaO‐1% K 2 CO 3 facilitates the clean and efficient combustion of coal sludge. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.