CASE STUDY: Rotary Union for Ethanol Plant

Ethanol Plant Gains Steam Tube Dryer Capacity with Rotary Joint Upgrades

Challenge:

Ethanol is a renewable fuel often blended with gasoline to reduce emissions. A recent study showed that greenhouse gas emissions from corn-based ethanol are 39% lower than gasoline.

Corn, LP produces ethanol and distillers grains, a co-product of ethanol production. Distiller grains are dried in steam tube dryers to use as a protein rich additive in livestock feed. As their ethanol production increased, Corn, LP needed to increase their drying capacity.

Corn, LP uses three large steam tube dryers. These dryers are 60 feet long and 12 feet in diameter. Wet cake enters one end of the dryer and dried distillers grains exit the other. The dryers slowly rotate as steam heated tubes dry the product. Corn, LP had increased dryer throughput, but the steam flow was bottlenecked by the original rotary joints, which were beyond capacity.

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Solution:

Corn, LP worked with Kadant Johnson to replace the existing 8” rotary joints with 10” self-supported ELSN™ rotary joints (pictured below). Torque restraint pedestals were also designed and installed with the rotary joints to prevent damage to attached flex hose piping.

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Results:

The larger 10” self-supported ELSN rotary joints have approximately 70% more flow capacity than the rotary joints they replaced, allowing Corn, LP to increase drying capacity. With the increased dryer capacity Corn, LP can increase ethanol and distillers grains production without the large capital investment of an additional steam tube dryer.