How to guarantee the profile of your oilseeds year-round

Spoiler: ‘You design for the worst conditions’

Author: Jamie Zachary 

It’s an issue many oilseeds producers face when operating in colder climates: How to guarantee uniform product temperature before flaking during processing year-round? 

For regions such as Europe, Asia-Pacific and South America where seasonal temperatures never (or rarely) dip below freezing, this might never be an issue. Yet in countries such as Canada where -20°C can be the norm for several months of the year, it creates several challenges when it comes to providing uniform and stable temperature and moisture of the seeds before further processing. This conditioning stage represents a significant process step that affects the efficiency of oil extraction and quality of the final product. 

“Beans or seeds such as canola/rapeseed and soybean that are stored in a silo are significantly affected by the ambient temperature,” says Stan Pala, Global Sales Director at Solex Thermal Science, who leads our company’s efforts within the world’s oilseeds market. 

In Canada, for example, the stored seeds commonly dip to between -10°C and -20°C. They then need to be heated to 55°C to 65°C, with the optimum temperature determined by the downstream equipment and process requirements for efficient oil extraction. 

“That’s a significant temperature gap to cross in one step," says Pala. "It means the challenge is not just being able to offer enough heat transfer area to meet the required outlet temperatures, but also account for fusion heat of the naturally contained moisture so you have a product with a consistent temperature and moisture profile before it moves to the next processing stage.”  

As he explains, a unit that’s designed solely based on summer operating conditions – for example 20°C to 30°C – will not be able to handle the same capacity in the winter when it drops below freezing. 

The solution? 

“You can design for the worst conditions,” says Pala of the vertical plate conditioner (pictured left) that Solex uses to prepare oilseeds for further processing. “That means the most extreme conditions – the coldest ambient temperatures."

And by the extreme conditions, Pala clarifies that means the maximum heat load that can occur – specifically the lowest oilseeds temperature and maximum moisture removal that is required, especially after a wet season. 

Pala notes there is a caveat, however. Designing for the “worst conditions” comes with a price that can be mitigated in some situations.  

“The bigger the temperature range and more the moisture removal, the larger the equipment and the more costly the overall solution,” he says. “In some cases, that’s unavoidable – for example, a region where ‘extreme’ can last months. But in others, it might not make economic sense to design for those temperatures when it’s only going to be like that for a couple weeks or just days a year.” 

For example, in regions where it only drops below -10°C for a couple weeks a year, the alternative might be to reduce capacity. By reducing the capacity of the throughput, it allows the beans or seeds to move slower through the conditioner – it provides them the necessary residence time to reach that target temperature, even in a smaller unit.  

“A customer can have capacity at 60 to 65 tph in the summer, but may accept 55 to 60 tph for a short time in the winter in order to keep the cost of the investment down,” says Pala. 

Other options?

Another possibility is to switch heating media during the coldest days. Instead of hot water, operators can use high-pressure steam in the bottom parts of the conditioner to boost the short-term performance. Once the seeds get warmer, the operators can switch back. 

“We will try to have as many discussions with the customer as possible to understand their needs and constraints. Through that discussion, we can end up helping that customer provide a high-quality conditioning solution that will also save them money in the process," says Pala. 

Even after installation, or a few years of operation, Pala notes it is not too late to address seasonal swings in ambient temperatures.  

“By adding plate banks in the existing conditioner, we’re able to provide the necessary heat transfer area to warm the beans or seeds to that ideal 55°C to 65°C for canola and 70°C to 75°C for cracked or whole soybeans," he says.  

“And if moisture removal is needed, there’s an opportunity to strategically inject necessary amounts of drying air at certain points in the conditioner to remove the moisture that the beans and seeds will release once they thaw out. 

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Want to learn more about Solex’s vertical plate conditioning technology. Visit our dedicated oilseeds portal, which includes videos, brochures and more. 

Ready to talk? Contact a Solex representative today.