Ethanol Production from Potato Waste

Ethanol Production from Potato Waste with Lyure Screw Presses

Introduction

Lyure Screw Press provides innovative screw press technology to enhance ethanol production from potato waste, a zero-value by-product from potato processing plants. This waste, primarily potato peel, is rich in starch and fermentable sugars, making it a viable feedstock for bioethanol production. Lyure’s equipment optimizes the dewatering process, improving efficiency and sustainability in ethanol plants.

Potato Waste in Ethanol Production

Potato waste, generated from peeling machines in facilities like those producing French fries or potato chips, contains:

High Starch Content: White starch from peeling, ideal for ethanol fermentation.

Moisture Content: Typically 86-93% moisture, requiring dewatering for efficient processing.

Whole Cull Potatoes: Often mixed with peel, necessitating shredding before processing.

Process Overview

The ethanol production process using potato waste involves several steps:

Shredding: Whole cull potatoes and peel are shredded to facilitate processing.

Enzymatic Liquefaction: Enzymes break down starch into sugars, creating a “beer” with 12-15% solids.

Distillation: The beer is pumped to a distillation tower, where alcohol is extracted, leaving stillage (solids and water).

Dewatering Stillage: Lyure screw presses separate stillage into:

Press Cake: Solids with ~75-85% moisture, used as cattle feed.

Press Liquor (Centrate): Thin stillage, often sent to wastewater treatment.

Further Processing: Press cake is trucked to farms, while centrate may require additional treatment.

Challenges in Processing Potato Waste

High Moisture Content: Stillage from distillation has 95% water, making it too thin for effective screw press separation without pretreatment.

Starch and Viscosity: Potato peel is slimy and starchy, requiring chemical aids like hydrated lime to enhance dewatering.

Economic Viability: Dewatering must balance cost with the value of by-products like animal feed.

Lyure Screw Press Solutions

Lyure Screw Press technology addresses these challenges with:

Enhanced Dewatering: When combined with hydrated lime (2-3% by weight), Lyure presses achieve press cake with 65-75% moisture, significantly improving solids content compared to 82% without lime.

Custom Configurations: Adjustable discharge cone pressure optimizes separation, producing clearer press liquor at low pressure or higher solids at high pressure.

Reaction Systems: Integration with lime dosers and reaction conveyors transforms slimy peel into a pressable cake, preventing screen blinding.

Benefits of Lyure Screw Presses

Cost Efficiency: Reduces haulage costs by lowering waste volume and moisture, enhancing the value of press cake as animal feed.

Environmental Sustainability: Minimizes wastewater treatment needs by producing clearer press liquor and supports renewable fuel production.

Versatility: Effective for both Russet and sweet potato waste, with lime treatment required only for Russet varieties.

Improved By-Product Value: Press cake with 65% moisture crumbles into a powdery form, ideal for cattle feed.

Current Process: A Sharples centrifuge separates solids to 85% moisture, with centrate sent to wastewater treatment.

Lyure Potential: Replacing centrifuges with Lyure screw presses, combined with lime treatment, could reduce moisture to 65-75%, improving feed value and reducing wastewater volume.

Limitations

Moisture Limits: Even with lime, press cake moisture remains above 65%, requiring drying for long-term storage or broader feed applications.

Lime Dependency: Russet potato waste requires precise lime dosing (3% by weight) to achieve optimal dewatering, adding to operational costs.

Stillage Thinness: Thin stillage (95% water) may still require centrifugation or other methods before pressing in some setups.

Conclusion

Lyure Screw Press technology enhances ethanol production from potato waste by efficiently dewatering high-moisture stillage and peel, producing valuable by-products like animal feed. With lime treatment and customizable press settings, Lyure presses address the challenges of starchy, slimy waste, offering a sustainable and cost-effective solution for ethanol plants. This technology supports the growing demand for bioethanol as a renewable fuel while repurposing zero-value waste.