Proposal of novel exergy-based sustainability indices and case study for a biomass gasification combine cycle integrated with liquid metal magnetohydrodynamics

Abstract

Exergy is considered a way to sustainability. Exergy-based analyses have been recently widely used for performance assessment and comparison purposes of energy systems from production to end-user while different sustainability related indices or indicators including exergetic concepts have been developed in the literature. In this regard, the present study proposed five different indices: (i) Exergetic Fuel Based Environmental Remediation Index (χ), (ii) Exergetic Product Based Environmental Remediation Index (δ), (iii) Exergetic Fuel Based Total Environmental Remediation Index (β), (iv) Exergetic Product Based Total Environmental Remediation Index (α), and (v) Improved Sustainability Index (ISI). These indices were applied to a novel Biomass-integrated Gasification Combine Cycle (BIGCC) integrated with Liquid Metal Magnetohydrodynamics (LMMHD). They allowed to perform a more complete environmental analysis by considering the exergetic cost of environmental remediation of the process. The average exergy efficiency values for the BIGCC, LMMHD and the overall system were determined as 0.491, 0.222 and 0.688 under daily ambient temperatures for a year and different air to fuel ratio (AFR) conditions, respectively. The average values for χ, β, δ, α and ISI were 1.636, 2.389, 1.949, 2.848 and 0.513, respectively.