Exergy Analysis of Integrated Methanol and Dimethyl-Ether Co-production Towards Net Zero Waste Emission

Abstract

The energy sector, currently dominated by fossil fuels, significantly contributes to carbon emissions and climate impacts. This study addresses the urgent need for renewable energy resources and promotes the utilization of waste from Malaysia’s palm oil industry. It proposes upgrading conventional palm oil mills to integrated mills to produce valuable biofuels such as methanol (MET) or dimethyl ether (DME). Using Aspen Plus V11 for simulation, mass and energy balances were provided for feasibility analysis, including techno-economic, exergy, and carbon analysis. The integrated process demonstrated 10 to 15% higher exergetic efficiency than conventional mills, enhancing the renewability index by 40% and reducing carbon emissions to 0.50 tonne CO₂ per tonne of palm oil. The integrated mills, operating at 61–64% exergetic efficiency, achieve a 28% reduction in exergy destruction when palm wastes are recovered and transformed into biofuels. Despite an 87% increase in non-renewable exergy consumption due to additional operating requirements, the overall renewability index remains high (around 0.9), demonstrating the commercial viability and environmental benefits of this approach. Overall, this study lays the foundation for integrated palm oil mill operation by utilizing palm waste to achieve net zero waste emissions, which is a positive outlook.