Energetic and Exergetic Analyses of Biomass Derived Syngas for Triple Cycle Power Generation

摘要

To rise the thermal efficiency of power generation systems and to meet stricter environmental regulations, improved system integration based on renewable energy is a viable option. In this context, a syngas fuelled Brayton/Rankine combined power cycle integrated with the Organic Rankine Cycle (ORC) is proposed and analysed from both energetic and exergetic point of views. A thermo-chemical model was developed to predict the composition of syngas produced after biomass gasification, and also, a thermodynamic model was developed, to determine the energetic and exergetic performance of the proposed triple cycle power generation system. We show that both first-law and second-law efficiencies of triple power cycle decreases with the increase in pressure ratio and increases with higher gas turbine inlet temperature. It is further shown that first-law and second-law efficiencies of solid-waste-derived syngas fuelled triple power cycle are considerably higher than the rice husk derived syngas fuelled cycle. The worst performing components from irreversibility point of view in the proposed triple cycle are the combustor, Heat Recovery Steam Generator (HRSG), and gasifier, respectively. Our results show that integration of ORC with the Biomass-Fuelled Integrated Gasification Combined Cycle (BIGCC) is very effective in improving the thermal performance of the power plant and in reducing external waste emissions.