Techno-Economic Assessment of Biodiesel Production from High-Free FattyAcid Non-Edible Nigerian Seed Oils

Abstract

The ongoing deregulation of downstream petroleum markets and the removal of fuel subsidies in Nigeria have drastically elevated commercial Automotive Gas Oil (diesel) prices, creating an urgent demand for economically viable and sustainable liquid fuel alternatives. Nonedible agricultural seed oils—specifically Rubber Seed Oil (Hevea brasiliensis), Neem Seed Oil (Azadirachta indica), and Jatropha Oil (Jatropha curcas)—represent promising renewable feedstocks abundant in Nigeria. However, their high Free Fatty Acid (FFA) content (10–16 wt%)renders conventional single-stage alkaline transesterification technically unfeasible due to severe saponification. This study presents a comprehensive desk-based Techno-Economic Assessment (TEA) of a decentralized, modular biodiesel production plant (capacity: 5,000 L/day; 1,650 metric tons/year) designed for processing high-FFA Nigerian seed oils via a two-stage acidcatalyzed esterification followed by base-catalyzed transesterification. Mass and energy balances, combined with major equipment sizing and cost scaling using the Lang factor method, established a total Capital Expenditure (CapEx) of $341,220 (~₦511.8 million) and an annual Operating Expenditure (OpEx) of $769,871 (~₦1.155 billion). Factoring in byproduct crude glycerol sales ($33,396/year), the Net Present Value (NPV) at a 10% discount rate over a 15-year plant life reached $1.82 million, with an Internal Rate of Return (IRR) of 34.2% and a discounted payback period of 3.1 years. The Levelized Cost of Fuel (LCOF) was determined at $0.453/liter (~₦680/liter), representing a substantial cost advantage over prevailing market diesel prices (~₦1,200–₦1,350/liter). Sensitivity analysis revealed that raw seed oil procurement cost accounts for 88.5% of total OpEx, proving that maintaining feedstock pricing below $0.55/kg is critical for long-term commercial viability. These findings confirm that decentralized modular processing of non-edible Nigerian seed oils is both technically sound and highly profitable, offering a practical blueprint for rural energy independence.