There’s a challenge facing the almond industry over the next few years that amounts to simple math: prices stay strong only when demand keeps up with supply, and supplies are rising quickly.
To solve that problem, the Almond Board is funding research into a new use for almond shells that could make them a valuable part of plastic manufacturing from disposable party cups to wood-polymer material for decks and fencing.
ABC President and CEO Richard Waycott told growers at the Sacramento annual conference that an increase in shell prices from $5 a ton to $50 a ton could help power a $500 to $600 million gain in annual revenues for growers from co-products.
So how would shells become a part of plastic manufacturing?
Torrefaction is the key. The process, which involves roasting shells to remove moisture and low energy volatiles creates a new product that is denser, easier to handle and move, and can be added to plastic.
The Almond Board has funded research into torrefaction of shells, and USDA researcher Bor-Sen Chiou says the results look promising, and shells could soon be useful in multiple markets, not just traditional ones.
“Almond shells were (historically) mostly used for bedding for dairy cattle. There’s a decrease in the number of dairy cattle farms in California, and there’s an increase at the same time of number of almond farms, so prices are going down,” Chiou said.
New markets for shells that have been torrefied include manufacturers of flower pots, garbage cans, containers for produce, and wood polymer composites to make decks and fencing.
“It’s a hugely growing market, the wood polymer composites,” Chiou said. “What we’re doing is formulating the best recipes for making these polymer composites with the best thermal and mechanical properties.”
Plastic with torrefied almond shells offers advantages over unadulterated plastic, because it can be both stiffer and more stable at high temperatures.
That’s an advantage because no one wants a flower pot, or a backyard deck, that melts or deforms in the sun.
Torrefied shells can be used in combination with polymers that sawdust can’t, including PET, a substance that’s stronger than polypropolene or ethylene, Chiou said.
Chiou’s team of researchers is working with California companies Grow Plastics and FDS to commercialize the technology. The USDA team plans to provide several thousand pounds of torrefied shells to the companies in 2018 so they can do a commercial scale dry run.
Growers should stay tuned as this Almond Board-funded research opens new markets for shells!