Why DDGS drying with superheated steam matters
Modern ethanol plants operate under constant pressure: energy prices remain high, customers demand consistent, sustainable feed quality, and any safety incident can halt production overnight. Yet one part of the process still hides substantial untapped value: the DDGS drying line, where conventional drum dryers remain common—proven and familiar, but energy‑hungry, hard to control for final moisture, and burdened with inherent fire and explosion risk. Upgrading this step not only improves efficiency and safety but also secures a reliable pathway to high-value animal feed production.
Upgrading these DDGS dryers with ExergyPSSD® replace hot air with a closed‑loop superheated steam process, dramatically cutting energy use, removing oxygen from the system to eliminate explosion risk, and enabling more precise control of DDGS quality. As a result, plants can produce consistent, high-value animal feed while improving safety and sustainability. By replacing traditional DDGS dryers with the ExergyPSSD® superheated steam system, producers can turn DDGS drying from a cost centre into a competitive advantage and achieve production, cost, and decarbonisation goals faster — and with lower project risk.
Turning a bottleneck into an energy asset
Pressurised superheated steam drying with ExergyPSSD® turns a production bottleneck into a competitive advantage across the plant. Instead of rebuilding the entire dryer island, the technology replaces the existing drum dryer with an ExergyPSSD® superheated steam dryer while fitting into the current line layout, foundations, and utilities.
During operation, water evaporated from the DDGS is recovered as useful, pressurised steam instead of being lost up the stack. This allows up to 80–85% of the latent heat to be recycled. In turn, it reduces net energy use to roughly 150 kWh per ton of water evaporated. As a result, plants that replace hot‑air DDGS drying with ExergyPSSD® achieve lower thermal energy consumption, fully recoverable vapour heat for other on‑site processes, and a lasting reduction in fuel costs and CO₂ emissions.
Oxygen free DDGS drying with superheated steam – eliminating explosion risk at the source
Because the process runs oxygen‑free, it eliminates the conditions that cause dust explosions, fires, and smouldering at the source. As a result, plants can simplify explosion protection and reduce dependence on complex gas‑treatment systems. They can also ease ATEX and NFPA compliance while improving working conditions for operators across the DDGS island.
In addition, the closed steam loop prevents emissions to the atmosphere. This means odour and VOC stacks common to hot‑air dryers can often be reduced or removed, strengthening local air quality and community relations. Together, these improvements create safer operations, lower insurance exposure, and higher availability for the DDGS line.
High-value animal feed DDGS – preserving protein and fat quality
DDGS drying with superheated steam does more than remove water. DDGS passes through the dryer in seconds under controlled, oxygen‑free conditions. This prevents oxidation and preserve amino acids and fat quality. At the same time, proteins transform into a less water‑soluble, rumen‑protected form without becoming denatured. As a result, a higher share of bypass protein reaches the small intestine. The outcome is fully sterilised DDGS with greater nutritional value, longer shelf life, and improved storage stability. Feed compounders value this performance, as it supports the production of high‑value animal feed and premium DDGS contracts. Therefore turning the drying step into a lever for feed‑market positioning rather than a cost.
Retrofit — replace, don’t rebuild
When we talk about retrofitting DDGS dryers, we mean replacing the existing hot‑air drum dryer with an ExergyPSSD® superheated steam dryer while keeping the rest of the plant largely intact. In practice, this means we design the new dryer to fit into your current layout and process, connecting to existing upstream and downstream equipment, utilities, heat source, and structural footprint, without reusing the old dryer shell itself.
From a project perspective, this retrofit approach offers a practical route to decarbonisation and growth because you avoid rebuilding the entire dryer island while still gaining a modern, high‑efficiency superheated steam system. The ExergyPSSD® solution combines a compact vertical dryer with integrated energy‑recovery and condensate‑handling units, enabling large‑scale industrial integration with a small footprint and low specific energy use per ton of evaporated water.
In operation, cyclones separate the dried DDGS and feed it into the existing cooling, storage, and load‑out logistics, so current material‑handling systems can remain in place. With few rotating parts and a robust design proven in 24/7 service since the late 1970s, the technology delivers high availability, low maintenance needs, and predictable lifecycle costs, as demonstrated by reference plants that are still running reliably decades after start‑up.
Next steps for decarbonisation and growth
For ethanol producers under pressure from regulators, customers, and investors to cut energy use, emissions, and safety risks, DDGS drying offers a tangible way to act on all three. By retrofitting existing drum dryers with ExergyPSSD® superheated steam technology, plants can reduce net energy consumption and CO₂ emissions. At the same time, they remove explosion risks inside the dryer, eliminate odour stacks, and upgrade DDGS into a consistent, high‑value animal feed with superior nutrient quality. For many large dry‑mill sites, transforming DDGS drying from a constraint into a strategic advantage is one of the fastest ways to boost competitiveness in a tightening market.
If you’d like to explore what’s possible, Swedish Exergy can support you with feasibility studies, energy‑balance calculations, and pilot testing of your own stillage in a superheated steam DDGS dryer. Together, these steps create a clear roadmap for your next investment. Contact us to discuss your DDGS dryer retrofit and next steps.
