Exergoecological Evaluation of Power Generation in Steam Cycles Fed by Biomass

Abstract

One of the methods to reduce environmental impacts is to use renewable resources such as biomass or even waste. In this work, a novel power generation system in biomass-powered steam cycles was proposed, comprising biomass gasification, a steam turbine, a pump and a condenser. A biomass feedstock (rice husk) was used in the gasifier as input fuel. The devised system was analyzed taking into account the sustainability evaluation that includes thermodynamic and environmental parameters. An energetic, exergetic and exergoecological analysis was carried out. In addition, a detailed sensitivity analysis was performed to assess the effects of varying operating parameters on system efficiency. According to the results, the energy and exergetic efficiencies of the system had a value of 23,680% and 12,830%, respectively, where the boiler and the turbine presented the highest average environmental impact per input and output exergy. The components with the highest environmental impact index associated with exergy destruction were the condenser and the boiler, representing 99,82%, demonstrating profit margins in the formation of pollutants and exergy destruction. The entire system had a total ecological impact of 2,614 mPt/s and can be reduced mainly by improving its exergetic efficiency. Exergoecological assessments can be used to support power generation in complex cycles, especially to reduce the generation of environmental pollution.

Keywords

• Exergoecology
• Exergy
• Rankine Cycle
• Biomass
• rice husk