Perpustakaan Digital ITB

Coal-fired power plants remain the backbone of Indonesia's electricity supply, yet they must be decarbonized to meet national net-zero emission targets. Direct biomass co-firing is technically limited to roughly 10% of thermal input, while carbon capture imposes a substantial efficiency penalty that requires careful evaluation before retrofitting. No comprehensive study has evaluated indirect co-firing through gasification integrated with carbon capture in a single simulation for an existing Indonesian plant. This study models and compares such an integration to determine the technical performance of both capture routes. A steady-state model of a 350 MWe subcritical unit was developed in Aspen Plus V14 and validated against plant operating data, with deviations below 3.4%. A circulating fluidized bed gasifier was modeled using a restricted-equilibrium approach and validated against published experimental syngas compositions. Three scenarios were evaluated at co-firing ratios of 10– 80% on an energy basis under constant heat input: co-firing without capture, pre-combustion capture applied to the biosyngas, and post-combustion capture applied to the flue gas, both using amine absorption at 95% removal. Co-firing itself left total emissions nearly unchanged while raising the biogenic carbon share to 79.6%. Pre-combustion capture supplied its regeneration heat internally but reached 38.63% energy penalty and became net-negative only at the highest ratio. Post-combustion capture maintained a 29.54% penalty, achieved net-negative operation across all ratios, and required one-third of the specific capture energy