Bioethanol Recovery & Dehydration: A BioSTEAM Techno-Economic Model
BioSTEAM · Python · Techno-Economic Analysis
SEPARATIONS + TEA · University Park, PA
98.4%
product purity
97.9%
ethanol recovery
$0.302/kg
solved MPSP
Ethanol and water form an azeotrope at 89.4 mol% (78.25°C); bubble-point sweeps located that wall from first principles, confirming distillation alone can't push past roughly 95 wt% ethanol.
Built an 8-unit fuel-ethanol recovery train in BioSTEAM (pump, preheat, beer column, rectifier, vaporizer, molecular sieve, condenser) processing 100 t/hr of 9 wt% fermentation beer.
The molecular sieve breaks through the azeotrope by adsorbing water preferentially, pushing the product to 98.4 wt% purity.
Its regeneration stream closes as a recycle loop that BioSTEAM converges iteratively, carrying 1,485 kg/hr (7.9% of fed ethanol) and lifting recovery from roughly 91% to 97.9%.
Ran a full techno-economic analysis: a subclassed BioSTEAM TEA priced $2.87M of installed equipment and solved a minimum ethanol selling price of $0.302/kg ($0.87/gal) at a 15% IRR over 20 years.
A sensitivity sweep on the rectifier's water recovery showed cost and stage count rise fast near the azeotrope, and the column fails to converge past a point, exactly the wall the molecular sieve exists to get around.
Fig. The converged 8-unit flowsheet: beer column, rectifier, and molecular sieve with its recycle loop back to the mixer.
