A chemist thinks he might have found a way to lift a hex from the oilseed crushing industry, potentially making it greener, safer, more efficient and less costly.
“The industry would rather not use volatile solvents, but distillation works pretty well,” professor Philip Jessop of Queen’s University in Kingston, Ont., said about why crushers use hexane despite its problems.
Jessop’s replacement requires less energy, causes fewer human health risks and can be washed in with a version of club soda and washed out with regular water rather than requiring expensive distillation.
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“Because we try to save energy and materials, it usually ends up being cheaper than the existing process, as well as being greener,” said Jessop, who calls himself a “green chemist.”
Hexane is a dangerous, gasoline-like solvent that is added to crushed oilseeds to separate the oil from the meal. Once the oil is separated, it has to be distilled to remove the solvent from the oil.
This is where the problems arise.
Distillation requires large amounts of energy and creates hazardous vapours that can injure plant workers.
Hexane is cheap, but the energy to distill it is not, and both the energy use and the hexane vapour cause greenhouse gas emissions.
Jessop said crushers face hefty insurance bills because of their use of volatile solvents such hexane that they distill, but they have not had any real options.
Jessop said he has found a way to create “switchable solvents,” which can be easily flipped from one form to another at different parts of the process.
The solvents he is experimenting with are added to carbonated water and crushed meal, which causes the oil to absorb the solvent and separate from the meal.
However, instead of distilling the solvent-oil mix to remove the solvent, the carbon dioxide is removed from the water, which causes the two to separate when the solvent suddenly becomes intolerant of the oil.
This gets rid of what Jessop calls the “Murphy’s law” of solvents: whatever is ideal in one stage of the process is terrible in the next stage.
Jessop’s more benign process still faces many hurdles before becoming commercially possible. The solvents he is using as replacements are not now used in food processing, so they would first need government health approvals and set standards.
Much fine-tuning would be required to establish specific amounts of carbonated water required to lower solvent levels to acceptable levels.
However, Jessop said this pioneering work demonstrates that one of the most negative elements of the oilseed crushing business can be replaced with a relatively harmless process.
“It proves that you can do this,” he said.
