Grain bins on Prairie farms are generally a lot bigger than they used to be. But have best practices for storage management kept pace?
Charley Sprenger, a research project lead at Prairie Agricultural Machinery Institute (PAMI) in Portage la Prairie, Man., addressed that question during her Canola Week 2021 presentation on canola storage.
“A lot of the grain storage management tools we have were developed prior to the 2000s, when the average bin sizes were around 2,000 to 4,000 bushels and grain depths were only around 10 to 20 feet,” Sprenger said. Today, typical bin sizes can range from 20,000 to 50,000 bushels with grain depths of 20 to 40 feet, she added.
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A challenge with larger bins is they contain more grain that needs to be cooled and dried in about the same amount of time as grain in smaller bins. On top of that, airflow resistance increases in larger bins, which makes conditioning the grain more difficult.
Sprenger referred to a PAMI air movement study that examined whether the 10-horsepower centrifugal fans running on single-phase power found in many grain storages are the right tool for drying canola in larger bins.
The 10 hp fans stalled out
The researchers wanted to know if they could achieve optimal conditions for canola storage for more than five months (determined to be eight per cent moisture and cooled to 15 C or lower throughout the entire bin) in bins with 25,000-bushel capacity. What they discovered in their trials was the 10-horsepower fan could not push air through the canola pile when the bin was full.
“We filled our 25,000-bushel bins with canola and measured resistance at the fan after each load,” said Sprenger. “However, the 10-horsepower fan stalled out at only 17,000 bushels.”
The researchers determined adding another fan wasn’t sufficient either. Two, 10-horsepower fans operating on opposite sides of the bin were tested in the same 25,000-bushel grain storages and they also stalled out before the bins were filled.
“There’s probably lots of opportunity to examine other fan and ducting configurations to find potential alternatives, but it shows it’s not just as simple as adding a second fan anywhere on the bin and you’ll get greater airflow,” Sprenger said.
A take-away from the project is 10-horsepower centrifugal fans will probably work in larger bins for something like corn, which has bigger seeds that produce larger void spaces in the pile, but it’s likely not sufficient for a crop with tiny seeds like canola, she adds.
Three-phase power upgrade
Equipping large bins with more powerful fans is one answer, but it’s not as simple as it sounds. A 10-horsepower fan is the maximum size you can use in a single-phase electrical system, so opting for a bigger fan could mean the added expense of upgrading to three-phase power for your farmyard.
“Larger fan installations will probably require utility upgrades to three-phase electric power to operate, which can be a hurdle to overcome to provide enough horsepower and, therefore, airflow rate to achieve drying,” Sprenger said.
“Alternatively, the recommendation that we often provide to condition canola (is to) dry it down in smaller bins, where it’s easier to achieve sufficient airflow with lower depths, and then place it in larger bins for more long-term storage if that’s necessary.”
Sprenger said the project shows more works needs to be done on determining the best fan requirements for larger bins. “Any alternative ducting systems and fan arrangements still need more validation to see what are some better scenarios.”
Sprenger stressed canola growers looking for guidance on production practices should always try to seek out resources that are canola specific — something she indicated could be even more important with the move toward larger storages.
“Bigger bins mean bigger risk, so make sure you have a management plan that’s specific for your requirements,” she said.
PAMI has an extensive resource library that includes articles and fact sheets on grain storage and drying, which you can find at the PAMI website. Prairie canola producers can also access online resources from the Canola Council of Canada and other organizations, Sprenger noted.
