Ash and deposit characteristics from oil-palm empty-fruit-bunch (EFB) firing with kaolin additive in a pilot-scale grate-fired combustor

Sintering profoundly influenced the process of the combination of Si and K to form K-silicates, which readily became molten under high-temperature combustion. Deposition intimately entailed a KCl-condensate, impeding the heat uptake by the heat transfer surfaces. Kaolin was found to be a very promising additive that could shift the equilibrium towards K-Al-silicate formation and hence remarkably discourage sintering and fouling. Complete pre-mixing of kaolin with EFB tended to be the most appropriate approach to counteract such problems. A sharp decrease in the deposit mass corresponded with a deposition flux of 4-12 g/m2h such that heat transfer to the air-water-cooled probe appeared to be unaffected.