Process Simulation and Comparative Techno-Economic Assessment of Fish Oil Recovery from Fish Heads via Supercritical CO2 Extraction and Enzymatic Hydrolysis

The valorization of fish processing by-products, particularly fish heads, represents an opportunity to advance the circular economy and reduce the environmental burden associated with organic waste. This study presents a process simulation-based techno-economic assessment of industrial-scale oil extraction from fish heads using supercritical fluid extraction (SCFE) and enzymatic hydrolysis extraction (EHE). Process models were developed in SuperPro Designer (V9.0) for a 50,000 kg/batch facility, integrating mass and energy balances, equipment design, scheduling, and economic analysis. All the results are derived from process simulations and have not been validated experimentally. SCFE yields a relatively high annual oil output (43.03 million kg/year) but is constrained by high solvent costs. EHE produces less oil (34.06 million kg/year) yet shows superior economic indicators, including a higher return on investment (24.77%), a shorter payback period (4.04 years), and diversified co-product revenues (cake, lecithin, soapstock), although it requires relatively greater capital ($862.7 million compared with $846.2 million for SCFE). While a full life-cycle assessment was not conducted, a partial resource inventory assessment indicates that EHE enables a biorefinery approach that improves resource efficiency. A sensitivity analysis revealed that the most favorable batch capacities were 50,000 kg for the SCFE and 150,000 kg for the EHE under the assumptions and throughput range examined. Overall, this simulation-based study underscores the economic and resource-efficiency potential of integrated biorefinery strategies for fish waste valorization, while highlighting the need for experimental validation and comprehensive environmental evaluation in future work.