Techno-economic and safety assessment of supercritical CO2 extraction of essential oils and extracts

Abstract

Currently, products based on herbaceous plants are receiving global attention due to the significant rise in human awareness of environmental protection and well-being. These products contain compounds with valuable medicinal and nutritional effects. However, extracting these substances via conventional methods can be challenging concerning economic and environmental effects. Compared to conventional techniques, supercritical CO2 extraction is a clean technology that mitigates environmental issues and enhances extraction yields. This work focuses on developing a commercial-scale closed-cycle process using supercritical CO2 as a solvent with the possibility of varying feedstock material. The full process encompasses the raw material pre-treatment, the scCO2 extraction of compounds, and solvent recovery. This multiproduct processing unit includes three products: essential oil from garden angelica and extracts from roseroot and maral root. The process model was established using Aspen Plus®. Parallel to process design, safety was assessed by a hazard and operability study (HAZOP) to evaluate possible deviations during the operation. For assessing the feasibility of the process, a comprehensive techno-economic assessment was conducted. With this analysis, it can be seen that the designed production process is not only feasible but also economically profitable. For an annual production capacity of 13,240 kg, considering the three products, capital expenditure of 5.4 M€ was estimated. As to profitability, an internal rate of return of 40% and a payback time of 2.5 years resulted. In addition to economic benefits of the designed process, waste production was reduced by recycling used solvents and employing different approaches for mitigating greenhouse gas emissions.