Hot ethanol extraction: economic feasibility of a new and green process

A new extraction process using ethanol at a temperature above boiling point is assessed from an economic point of view. The study was based on an assessment of the main operating costs adjusted by Lang’s factor. Operating costs were assessed based on energy consumption calculated using a model of the process developed from experimental results, and for a hypothetical unit with a 160 000 t/year rapeseed crushing capacity. The processing cost was estimated at 47.4 € per ton of processed seed. Amortization represented 35% of this cost, energy 32% and manpower 10%. Uncertainty about investment is the main factor that could lead to significant error in this cost, but this uncertainty could be offset by an adjustment of the amortization duration, most of the equipment being durable. Profit generated by the process relies principally on a better valuation of the meal: higher value comes from higher protein content and quality on the market for GM-free high protein feedstuffs. Oil quality is also improved by a lower oleic acidity, low phospholipid content and pigment concentration. This gain was estimated at 2.5% of the crude oil value. Unlike the conventional hexane process, hot ethanol extraction produces molasses in small proportions. Molasses value was set at 70% of corn price. The process profitability appears sufficiently positive to justify further research to test the hypothesis underlying our model. The main uncertainty lies in the performance of the process in real conditions of counter-flow extraction and solvent regeneration.