Anyone involved in the transportation of distiller’s dried grains (DDGs) knows just how challenging this product can be to move around. Its low bulk density makes filling trucks and railcars a constant challenge, while bumpy, humid cross-country trips can transform DDGs into a solid brick by the time they reach their destination. Anyone who has ever banged endlessly on a railcar with a sledgehammer trying to get hung-up DDGs to flow through the gate can attest to the difficulty of DDG loadout. Understanding the common issues that arise with dried distillers’ grains and knowing how to address them can make for more efficient DDG loading and unloading processes and help avoid the damaging impacts of heat, moisture, or mold.

The potential for delays and railcar damage when working with DDGs has even led some railroad carriers to ban the use of their hopper cars for transporting DDGs. Fortunately, standardization of operating procedures and using the proper DDG transportation tools can help minimize these issues in your operations. Facilities can also benefit from consulting with a reliable bulk material flow specialist like Pneumat Systems and implementing specialized railcar loading equipment like the RailSpreader, or truck and railcar unloading equipment like the HopperPopper.

What Are DDGs?

Distillers’ dried grains, or DDGs, is a nutrient-rich co-product created during distillation or dry-milled ethanol biofuel production. They are used as a high-protein feed ingredient and are often corn-based, although DDGs can be composed of rice, wheat, barley, or other grains.

The popularity of DDGs as a feed product for farm animals and livestock is rising, requiring new tools and technologies to minimize the difficulties of transportation of this commodity on railcars and cargo ships. Farmers find DDGs to be an excellent ingredient for producing high-quality animal fodder, and it is routinely used in feed mixtures for:

  • Beef cattle
  • Dairy livestock
  • Swine
  • Poultry
  • Fish / Aquaculture

Logistics specialists must stay vigilant when inspecting DDGs to determine if any mold growth or other damage has occurred during transportation since low-quality feed ingredients can be detrimental to livestock health.

5 Common Challenges When Transporting DDGs

Although DDGs are an excellent source of protein for animals, problems can occur during DDG transportation and storage that significantly impact the efficiency and cost-effectiveness of each shipment. You can minimize the amount of time and money spent sorting out DDG logistics issues by staying aware of common DDG transit problems and implementing practical solutions as they arise.

1. Making Weight

Depending on the precise formulation, DDGs have a bulk density of about 27–35 lb/ft3. Combined with a steep angle-of-repose that can range from 30°–45° or beyond, it’s easy to see why it can be so challenging to fill a railcar. When railcars ship out under-filled, transportation costs skyrocket. To get more DDGs into their railcars, facilities may require workers to top off the cars by manually pushing material around with shovels. This challenging, dirty work exposes workers to safety hazards and results in poor morale and retention issues. By implementing a high-density railcar loading system like the RailSpreader, loadout facilities can save hundreds of dollars per car while reducing dust and improving safety conditions for workers.

2. DDG Variability

There can be many variabilities for different DDG formulations, and the properties of the distillers’ dried grains generated at one ethanol plant can vary significantly from those produced at another. Formulations that contain high fat content are known to set up hard in storage vessels, while those with less fat will often flow more freely. DDG handlers must pay attention to many factors that impact the quality and flowability of the product, including:

  • Ambient temperature
  • Dryer temperature
  • Dryer exit moisture content
  • Grain particle size
  • Storage bin design
  • Bulk density
  • Condensed solubles proportions


3. DDG Stickiness & Caking

Stickiness and caking are two of the most common problems that come with DDG transportation. The dry particles that compose DDGs can stick together during transport if moisture accumulates in the truck or railcar, especially if they are loaded hot. Eventually, as DDGs continue to absorb water vapor from the atmosphere, the individual particles begin to fuse into solid clumps. Severely caked DDGs can require many aggravating hours with a spade and pickaxe to clear.

When DDGs harden inside a bin or silo, buildup, bridging, ratholing, or plugging can occur. In these instances, a visit from a reliable cleanout crew like TeamPneumat may be warranted. Many operators choose to purchase Pneumat’s BinDrill and Dual Impact BinWhip systems so they can rapidly clear hung-up DDGs from their storage vessels and keep their facility running at 100% capacity. Make sure your team is adequately trained in the safe use of these tools.

Generally, the moisture content of DDGs must stay below 11% to prevent product caking that can result in costly, time-consuming railcar unloading issues or spoilage that can result in product loss. However, even heavily-caked DDGs can be unloaded with relative ease at properly-equipped facilities. Truckers have been known to drive miles out of their way to dump their loads at facilities equipped with air blast unloading technology. By driving a probe deep into the packed material and delivering powerful blasts of compressed air, sticky DDGs can be refluidized for rapid unloading without poking, prodding, knocking, and rodding.

Removing caked DDGs takes up time, energy, and resources, increasing transportation costs. Several practical railcar and truck loading and unloading tools from Pneumat Systems can assist in managing caking issues to help DDG shippers increase productivity and lower transit costs considerably.

Unpredictable environments and temperature fluctuations can take their toll on DDGs, but any action that can be taken to keep the product cool and dry will help ensure that loading and unloading go as smoothly as possible. Also, managing the transportation process in a way that limits the amount of time that DDGs are allowed to sit inside a transport hopper or storage vessel can go a long way towards keeping the product flowable.

4. Mycotoxins and Mold

Mycotoxins are naturally occurring toxic compounds found in foods that can cause a range of adverse health effects. Like any other bulk grain product, DDGs are susceptible to mold spore growth and mycotoxins that indicate spoilage or contamination — and DDGs come with a unique set of risk factors.

According to nutritionist Dr. Max Hawkins, mycotoxins can concentrate three times more within DDGs when compared with other grain types. Reducing mycotoxin growth in DDGs comes down to adequate grain storage and fast, controlled shipments.

DDG contamination during transit can pose a costly challenge for your logistics company or feed processing plant. Proper ventilation and temperature control systems are critical for keeping moisture levels low and preventing mycotoxin growth in DDGs.

5. Loading and Unloading Delays

Mistakes, miscommunication, and improper handling can cause delays in the transportation and handling of DDGs. The obstacles to railcar loading and unloading can be addressed using specially-engineered DDG handling equipment, such as the RailSpreader or HopperPopper. Ethanol plants, feed mills, integrators throughout the world have benefitted from consulting with experienced bulk material flow specialists about the available tools. Equipment installations that allow for faster, more efficient DDG loading and unloading can put a lot of money back into a facility’s pocket and typically generate a positive return on investment very quickly.

The Best DDG Loading & Unloading Tools

Flow issues and other DDG transportation problems have long been a source of frustration for railcar loading and unloading professionals. Low loaded railcar weights or time and energy spent battling caked material can add to shipping costs significantly. Companies like shipping and logistics providers, animal feeding operations, pet food processors, feed mills, and anyone involved in getting DDGs from Point A to Point B need to constantly assess these challenges and invest in equipment and planning to overcome these obstacles.

Pneumat Systems is proud to engineer systems that accelerate DDG transit and reduce product spoilage or damage while enhancing worker safety. Contact Pneumat Systems now to learn more about our DDG transport solutions, so you can keep the DDGs flowing as you carry out your essential role in helping feed the world. 🅿

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