Pyrolysis and combustion characteristics of an indonesian low-rank coal under O₂/N₂and O₂/CO₂ conditions

Pyrolysis and combustion characteristics of an Indonesian low-rank coal are studied under oxy-fuel (O₂/CO₂) and air (O₂/N₂) conditions using a drop tube furnace (DTF) and a thermogravimetric analyzer (TGA). Raw coal, dried coal, and binderless briquette samples of the same coal were used in the experiments, and the effects of drying and binderless briquetting on the reactivity of the coal under different conditions were investigated. Chars were prepared in the DTF in both N₂ and CO₂ atmospheres in the temperature range of 800−1400 °C. The reactivity of chars under oxy-fuel and air conditions was analyzed in the TGA. The coal reactivity under oxy-fuel conditions differed from that under air combustion conditions. The temperature at which significant gasification of the coal and char took place in the concentrated CO₂ gas stream was also identified. Characteristics of chars from different conditions were compared. Drying and briquetting had some noticeable influences on the reactivity of the coal under oxy-fuel conditions