Distiller's Grains Dewatering with Dual Decanter Centrifuges
Enhancing Solid-Liquid Separation Efficiency and Reducing Thermal Drying Costs for a Major Distillery
Project Background
A leading distillery required a reliable mechanical dewatering solution for their distiller's grains (whole stillage), a primary byproduct of their fermentation and distillation operations. Effective separation is critical to their profitability: the recovered solids are dried and sold as high-protein animal feed (DDGS), while the clarified liquid (thin stillage) is either recycled as backset or evaporated into syrup.
Customer Challenges
- High Thermal Drying Costs: Previous dewatering methods left excessive moisture in the wet grains, requiring massive energy consumption in downstream rotary drum dryers.
- Poor Solids Capture: Incomplete separation resulted in too many suspended solids carrying over into the thin stillage, which fouled the evaporators and reduced heat transfer efficiency.
- Equipment Wear: The fibrous and slightly abrasive nature of the grain slurry caused rapid wear on existing separation equipment, leading to unacceptable maintenance downtime.
- Capacity Bottlenecks: The plant needed a robust system capable of handling continuous, heavy-duty loads during peak production periods without constant operator intervention.
The ZK SEPARATION Solution
After evaluating the facility's feed characteristics and throughput requirements, we installed two LW430x1850C two-phase decanter centrifuges operating in parallel. This dual-machine configuration provides the necessary processing volume while ensuring built-in redundancy for 24/7 distillery operations.
Economic Benefits & Process Improvements
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Maximized Moisture Reduction
The LW430 decanter applies high centrifugal force (up to 3000+ G) to squeeze free water from the fibrous structure of the grains. Producing a consistently dry cake (typically 30-35% dry solids) significantly cuts the natural gas consumption required for the final thermal drying stage.
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Enhanced Solids Recovery
With an optimized length-to-diameter ratio (4.3:1), the centrifuge provides ample clarification time. This ensures maximum capture of fine proteins and yeast cells into the wet cake, increasing the total yield of marketable DDGS.
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Evaporator Protection
By producing cleaner thin stillage with minimal suspended solids, the centrifuges prevent rapid fouling of the plant's evaporator tubes, extending the time between necessary clean-in-place (CIP) cycles.
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Reliable, Wear-Resistant Operation
To combat abrasion, the centrifuge scroll is heavily protected with tungsten carbide hard-facing at key wear areas. Coupled with a heavy-duty planetary gearbox, the equipment handles dense solid loads with minimal maintenance interruptions.
Project Overview
- Industry Distillery / Food & Beverage
- Application Stillage / Distiller's Grains Dewatering
- Equipment 2 × LW430x1850C
- Bowl Diameter 430 mm
- L/D Ratio 4.3
- Separation Type Two-Phase (Solid-Liquid)
- Operating Mode Continuous, 24/7
On-Site Operation & Installation
The two centrifuges were integrated directly into the facility's existing stillage handling line. The compact footprint of the LW430 units allowed for straightforward installation, while the automated PLC control panels enabled operators to easily adjust differential speeds on the fly to match varying feed conditions.
