Performance evaluation of high-ratio biomass co-firing with low-rank coal in a 100 MWe circulating fluidized bed power plant

Department of Mechanical and Industrial Engineering, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Biomass co-firing has emerged as a practical approach for reducing fossil-based emissions in coal-fired power plants while utilizing existing infrastructure. This study evaluates high-ratio biomass co-firing up to 80% using woodchip in a 100 MW Circulating Fluidized Bed (CFB) power plant. The analysis was performed using GateCycle simulation under full-load operating conditions, covering thermodynamic, environmental, and economic aspects. The results show that increasing biomass fraction leads to higher fuel consumption, higher auxiliary power demand, and increased boiler heat losses, resulting in gradual reductions in boiler and plant efficiency due to the lower heating value and higher moisture content of biomass fuel. On the other hand, biomass co-firing significantly reduces specific CO₂ emissions from approximately 1050 kg/MWh to around 280 kg/MWh at 80% co-firing, while SO₂ emissions also decrease due to the lower sulfur content of biomass. Preliminary slagging and fouling assessment indicate that higher biomass fractions increase ash deposition tendency inside the boiler. The preliminary economic evaluation suggests that biomass co-firing remains economically feasible under the investigated operating conditions. Overall, the use of woodchip as a co-firing fuel shows promising potential for supporting decarbonization in existing CFB power plants, although high biomass utilization may reduce thermal performance.