Comparative Investigation of Solar-Based and Conventional Distillation Systems for the Extraction of Eucalyptus Camaldulensis Essential Oil

Abstract

Essential oil of Eucalyptus camaldulensis (E. camaldulensis) is commercially valuable with dominant constituents, often 1,8-cineole (eucalyptol). Smallholders and decentralized processors are increasingly exploring solar thermal systems to reduce fuel costs and emissions without compromising oil quality and quantity. In current study, we conducted side-by-side water-cum-steam distillations of fresh E. camaldulensis leaves (5 kg per batch) using a fixed-focus Scheffler concentrator based solar distillation system and a methane gas fired conventional distillation still. Gas chromatography (GC-MS) analysis was used to profile the essential oils and analysis of variance (CRD) was used to test yield differences in both distillations systems. According to the results, average oil yields were 33.13 and 31.38 grams in the case of solar-based and conventional distillation systems, respectively. Eucalyptol was the major component in both oils (53.30% and 56.20% concentration), with β‑pinene, α‑pinene, and p-cymene present in both chromatograms. The overall efficiency of solar-based distillation system during trials was around 30% and cumulative energy-yield trends suggested an inception of appreciable oil release up to approximately 54 MJ of input energy and near-complete recovery at approximately 96 MJ for a 5 kg raw material load. Considering the yields and local fuel pricing, the solar-based distillation system reduced the payback period by 1.6 years relative to the conventional system due to savings in fuel consumption. This study concludes that solar-based distillation delivers desired yield and acceptable oil composition, comparable to conventional distillation system, while reducing energy consumption and cost. Suitability of solar distillation systems should be supported for on-farm and small-scale processors in sunny regions.