A free-span building is the most practical choice for storing dried distillers’ grains, or DDGs. With long dimensions, high ceilings, and wide-open interior spaces, tension fabric buildings can accommodate high-capacity grain storage as well as working equipment and vehicles, all under one roof.
DDG, or DDGS (the dried product with added solubles), are popular feed additives for livestock and poultry. They are the most significant by-products of fuel ethanol produced from corn and other crops. In addition, breweries and beverage distilleries produce more than a million tons of DDGS each year. Much of this product is exported, which means it must be transported long distances and stored without losing its value.
Free-Span Advantages for DDGs or DDGS Storage
Co-ops and bulk port storage facilities, which handle large volumes, can improve their operations with free-span structure when compared to using traditional vertical silos. Here are some of the reasons why.
- Silos are not well insulated, so temperature regulation can be problematic.
- Free-span buildings of up to 300 feet make it easy to create the proper environment for storing DDGS.
- Silos are slow to fill and also to empty since they rely on gravity. Their configuration can exacerbate flowability issues common to DDGS and hinder transportation activities.
- Free-span buildings are designed for flat storage, so they can accommodate:
- Very large storage volumes, with product protected inside a fully enclosed building.
- Unrestricted heavy-equipment access and movement for loading and unloading.
- Transport systems, such as conveyors, that can be suspended or floor mounted.
- Multiple types of storage or other uses, together in one building.
- A single tension fabric structure can take the place of multiple silos, making construction more efficient and cost-effective.
In an article written for Dry Bulk magazine, Legacy’s Paul Smith describes five dry bulk storage challenges that can be solved by choosing a tension fabric building:
- Speed of construction
- Logistics of loading/unloading
- Indoor-outdoor working environment
- Corrosion
- Versatility
The Legacy Building Solutions team worked with farmer-owned cooperative AGRILAND FS to design a three-in-one fertilizer storage facility using the same innovative engineering/features that could easily be applied to a custom-designed DDGS storage building. And this building was constructed in just 23 days! Take a look.
Moisture Creates Multiple Challenges
Fresh distillers’ grains can be used wet as feed additives, but only if they are used quickly, especially during warm summer months. Otherwise, quality degrades, and the product can begin to spoil. Drying the distillers’ grains to 12% or lower moisture content makes them storable for a long time—years, even. That enables local producers and farmers to stockpile them, and it makes international transport possible. The economic benefits are obvious, but only if the product remains dry.
Although DDGS can be stored outdoors if you cover it, access is inconvenient, and this is not a long-term solution. Inside a building, moisture that causes structural corrosion is also a serious threat to DDGS in storage.
Over time, DDGS can absorb moisture from its storage environment, a risk that increases with higher relative humidity and warmer temperatures. Increased moisture content can encourage growth of mold, mildew, and bacteria and invite insects often associated with grain storage. It also increases DDGS density—product particles can clump, cake, or become nearly solid, reducing flowability. Handling becomes very difficult, and the product must be reground for use.
Successful DDGS storage requires more than a huge footprint and roof overhead.
The Legacy Difference
Each Legacy tension fabric building offers all the benefits of any free-span grain storage building and then some. Custom design from the ground up means you can get the footprint and features needed to make your building function efficiently. ExxoTec™ fabric is inherently corrosion resistant and nonconductive, helping protect against moisture intrusion and control interior temperatures year-round. Passive ventilation systems support natural airflow to help regulate interior temperatures without additional costs or effort.
Owners and operators can also look forward to a positive return on investment because many of the features that make Legacy buildings unique also help reduce ongoing maintenance and energy costs. Talk to a tension fabric building expert to learn how you can improve DDGS storage.
