A Methodology to Evaluate Solvent Extraction-Based Processes Considering Techno-Economic and Environmental Sustainability Criteria for Biorefinery Applications

Abstract

Extraction processes are widely used in biorefinery applications to recover target products from biomass, and their comprehensive evaluation is key to improving their economic and environmental sustainability. This paper applies a systematic methodology that combines a rigorous process design, techno-economic analysis, and life cycle assessment to evaluate the sustainability performance of solvent extraction-based processes, with a focus on downstream activities. The methodology, which consists of seven iterative steps that combine process simulation and economic and environmental sustainability assessment tools, is demonstrated using a biodiesel production process from algae biomass, with hexane as the lipid extraction solvent. The minimum biodiesel selling price is estimated at U.S. $8.95 per U.S. gal, using the discounted cash flow rate of return. This is 3.5 times the average price of fossil diesel, mostly due to the cost of algae biomass and lipid recovery capacity of the solvent. Eighteen environmental impact categories are estimated from cradle to grave using the ReCiPe v1.1 method. For example, the climate change and primary energy demand are calculated at 95 g CO2 eq./MJ and 1.52 MJ/MJ biodiesel, which are 5 and 24% higher compared to fossil diesel, respectively. Lipid extraction is identified as the hotspot of the downstream processing stages for all impact categories (52–97%) and an opportunity for improving the overall sustainability performance of algae biodiesel, e.g., solvent selection. These findings provide a benchmark for future improvements to biodiesel production from algae biomass, with focus on the interactions between biomass and the solvent, e.g., phase equilibrium thermodynamics.

Integrating Technoeconomic, Environmental, and Safety Criteria in Solvent Screening for Extraction Processes: The Case of Algae Lipid Extraction

“…21,42 The solvent-to-dry-feed-mass ratio is assumed to be 5:1, based on the study of Davis et al, 27 who reported commercial lipid recovery over 90% from wet algae biomass (20% dry weight). Also, modeling studies by Zapata-Boada et al 52 show that the solvent-to-feed ratio does not significantly affect triolein recovery from wet algae biomass (20% dry weight) when the mass ratio is above 3. The EXTRACT model in Aspen Plus is used to simulate the extraction column.…”

“…To compare solvents’ performance, it is assumed that a countercurrent extraction column with five stages is needed to extract lipids from algae biomass, based on the study of Stephenson et al The temperature and pressure for the extraction process are assumed to be 25 °C and 101.325 kPa, respectively, which are typical values for algae lipid extraction. , The solvent-to-dry-feed-mass ratio is assumed to be 5:1, based on the study of Davis et al, who reported commercial lipid recovery over 90% from wet algae biomass (20% dry weight). Also, modeling studies by Zapata-Boada et al show that the solvent-to-feed ratio does not significantly affect triolein recovery from wet algae biomass (20% dry weight) when the mass ratio is above 3.…”

Solvent Selection for the Extraction of 2-Phenylethanol from Aqueous Phases: Density and Viscosity Studies

“…Thus, indicators that understand the impact on the environment, health, and safety (HSE) must be considered . Another important indicator in solvent selection is process indicators, usually obtained from process simulators such as Aspen Plus . However, including these separation processes in commercial simulators requires an initial knowledge of the thermodynamic, physicochemical, and transport properties of the mixtures .…”

“…26 Another important indicator in solvent selection is process indicators, usually obtained from process simulators such as Aspen Plus. 27 However, including these separation processes in commercial simulators requires an initial knowledge of the thermodynamic, physicochemical, and transport properties of the mixtures. 28 Then, the experimental validation of the predictions made by the models of the behavior of real multicomponent mixtures is the first stage when designing new separation processes.…”

Improving the Environmental Sustainability of Polyketides Colorants Production by Talaromyces Strain through Better Hydrodynamic Design in Bioreactors

“…For instance, life cycle assessment (LCA) and the environmental management tool can be used as a process design tool if implemented at early design stages . While there are several sustainability studies on biotechnological processes reported in the literature, these have mostly focused on biodiesel production , and high value-added chemicals derived from microalgae such as red anti-oxidant carotenoid astaxanthin , and β-carotene . Nevertheless, costing evaluations and LCA studies on colorant production from fungi cultures have been lacking.…”