Comparative Performance of Bio-Based Solvents in Industrial Extraction Processes

Thesis Abstract

The rapid shift toward sustainable manufacturing has intensified the use of bio-based solvents in industrial extraction, yet comparative performance data under real-process conditions remain fragmented, limiting technology transfer and optimization across sectors. This study addresses the problem of inconsistent solvent performance characterisation by evaluating bio-based solvents against conventional petrochemical counterparts in representative extraction workflows, with particular emphasis on selectivity, recovery, energy demand, environmental impact, and process economics. The aim is to quantify how bio-based solvents influence extraction efficiency, product quality, and lifecycle sustainability across multiple feedstocks and target compounds. Specific objectives include (1) to compare solvation power, selectivity, and mass transfer resistances of platform bio-based solvents (e.g., ethanol-based, limonene, and 2-MeTHF) with conventional solvents (e.g., hexane, toluene) across three standard extraction scenarios; (2) to optimise process parameters through design of experiments to identify interaction effects between solvent type, temperature, and solvent-to-feed ratio; (3) to assess environmental and economic performance using cradle-to-gate life cycle assessment (LCA) and technoeconomic analysis (TEA); (4) to develop a predictive framework linking solvent properties to process outcomes; and (5) to propose guidelines for solvent selection in industrial practice. The methodology adopts a mixed-methods research design combining experimental bench-scale and pilot-scale data with comparative modelling. The population comprises three representative feedstocks vegetable oil seeds, lignocellulosic biomass, and edible oils, with a total of 18 extraction runs per solvent, including triplicate trials to ensure reproducibility. Data collection employs gravimetric yield measurements, GC-MS and NIR spectroscopy for product quality (e.g., fatty acid profile, impurity levels), Karl Fischer titration for moisture, and rheological monitoring for process viscosity. Analytical techniques include ANOVA and multivariate regression to quantify the effects of solvent type and process parameters on yield and impurity formation, as well as response surface methodology to identify optimum conditions. LCA follows ISO 14040/44 with functional unit per kilogram of extract produced, incorporating solvent recovery rates and energy consumption, while TEA utilizes capital and operating cost models to compute net present value and payback period. To ensure reliability, instrument calibration, method validation, and inter-laboratory comparison are incorporated, with cross-checks against published solvent performance data. The anticipated findings indicate that bio-based solvents can achieve comparable or superior extraction selectivity and product quality to conventional solvents under optimized conditions, with notable reductions in volatile organic compound emissions and solvent losses. It is expected that 2-MeTHF and ethanol-rich systems will demonstrate favorable mass transfer coefficients in lignocellulosic matrices, while limonene shows promise for non-polar extracts, albeit at higher solvent costs unless recovery is enhanced. The study also anticipates trade-offs between energy input and solvent recovery efficiency, highlighting the critical role of process integration and solvent recycling. The contribution to knowledge includes a robust, cross-sector comparative framework that links solvent physical-chemical properties to tangible process performance and sustainability metrics, enabling objective solvent selection and risk assessment for industrial extraction. The theoretical underpinnings integrate diffusion-reaction models with Hansen solubility parameters and Green Chemistry principles, complemented by Rogers’s sustainability transition theory to interpret adoption barriers and policy implications. The main conclusion is that strategically selected bio-based solvents can meet industry performance criteria while delivering measurable environmental and economic benefits, provided that process parameterization, solvent recovery, and supply chain considerations are optimised. Recommendations address (i) the development of solvent selection matrices for specific extraction targets, (ii) investment in integrated energy–solvent recovery systems, (iii) standardisation of performance benchmarks to facilitate cross-sector comparisons, and (iv) policy incentives to accelerate the adoption of bio-based solvents in industrial extraction, supported by open-access data repositories and collaboration between academia and industry.