Green steam for sustainable extraction of essential oils using solar steam generator: A techno-economic approach

Abstract

Essential oils are natural volatiles extracted using steam. Steam generation is an energy-intensive process and is invariably based on fossil fuels, briquettes or biomass. Based on the volumes of essential oil extracted, it can be considered as significant contributor to greenhouse gases. Though a lot of work is reported on essential oil extraction and characterisation, method for quantification of exact steam requirement and means for achieving it through sustainable source is not much reported.Through this study, steam requirement of 750 g/ml of Betel leaf volatile oil extracted and quantification of energy requirements for the extraction process is determined. For adoption of sustainable and clean energy source, opto-geometric optimisation and concentrating solar collectors (CSC) area calculation are carried out. The design of three CSC, namely, Linear Fresnel Reflector (LFR), parabolic dish collector (PDC) and parabolic trough collector (PTC), resulted in 78 m2, 122 m2 and 138.87 m2 of area to meet the steam requirement of the process.Adoption of CSC technologies for steam generation and replacing the prevalent technology needs detailed analysis and techno-economic comparison. This paper also focuses on cost-benefit analysis, taking into account CAPEX, OPEX, life-span, return on investment, levelized energy (steam) cost and the profitability index of net present value, payback period and internal rate of returns to check the economic feasibility of renewable energy. Analysis indicates that the cost associated with unit steam generation through CSC over the specified period is lower than a briquette-based steam generation. On adopting this sustainable technology for betel leaf oil extraction, even if the initial cost seems to be high, the payback period of LFR and PTC are 1.10 and 2.45 years, respectively. Based on this study, CSCs can provide a sustainable green solution for the extraction of essential oils.