Activated carbon 1 Bioadsorbent 1 Carbonisation 1 Carbonisation-activation 1 Carbonization 1 Chemical activation 1 Heat insulation layer 1 Heat transfer 1 Low-cement castables 1 Oil palm 1 Oil palm kernel shell 1 Palm oil 1 Retention time 1 Stainless steel 1 Steam 1 Steam activation Steam flow rate 1 Steel fibers 1