Change of combustion characteristics of Indonesian low rank coal due to upgraded brown coal process

Upgraded brown coal (UBC) process has been developed to produce a dry upgraded coal which is comparable with a bituminous coal. Differential thermal and thermogravimetry analyses (DTA–TG) have been applied to study the combustion characteristics of some Indonesian raw and upgraded coals produced by the UBC process. DTA–TG profiles of the entire combustion process can be used to predict the combustion performance of the pulverized coal in industrial furnaces. By using three samples of Indonesian low rank coals coming from Taban, Berau and Samaranggau, East Kalimantan, which have been upgraded by the UBC process, the ignition temperature (Tig) of the upgraded coals increased. Whereas the temperature, at which the maximum combustion rate occurs (Tmax), is not so changed. The DTA combustion peaks, which reflect the specific energy of coals, and the upgraded coals are significantly increased compared to those of raw coals.