Manufacturing tires from biomass could make the tire industry, along with other rubber-based products, more environmentally sustainable and economical, according to University of Minnesota researchers.
The new tire technology has been patented by the University of Minnesota and is available for licensing.
A study, published in the American Chemical Society’s ACS Catalysis, details the chemical process used to make isoprene, the key molecule in car tires, from renewable products like trees, grasses or corn.
“This research could have a major impact on the multi-billion dollar automobile tires industry,” said Paul Dauenhauer, a University of Minnesota associate professor and lead researcher of the study. Researchers from the University of Massachusetts Amherst and the Center for Sustainable Polymers, a National Science Foundation-funded center at the University of Minnesota, also authored the study.
Biomass-derived isoprene has been a major initiative of tire companies for the past decade, with most of the effort focused on fermentation technology, similar to ethanol production. However, renewable isoprene has proven a difficult molecule to generate from microbes, and efforts to make it by an entirely biological process have not been successful.
Funded by NSF, researchers from the Center for Sustainable Polymers have focused on a new process that begins with sugars derived from biomass including grasses, trees and corn. They found that a three-step process is optimized when it is “hybridized,” meaning it combines biological fermentation using microbes with conventional catalytic refining that is similar to petroleum refining technology.
The first step of the new process is microbial fermentation of sugars, such as glucose, derived from biomass to an intermediate, called itaconic acid. In the second step, itaconic acid is reacted with hydrogen to a chemical called methyl-THF (tetrahydrofuran). This step was optimized when the research team identified a unique metal-metal combination that served as a highly efficient catalyst.
The process technology breakthrough came in the third step to dehydrate methyl-THF to isoprene. Using a catalyst recently discovered at the University of Minnesota called P-SPP (Phosphorous Self-Pillared Pentasil), the team was able to demonstrate a catalytic efficiency as high as 90 percent with most of the catalytic product being isoprene. By combining all three steps into a process, isoprene can be renewably sourced from biomass.
The University of Minnesota technology follows other recent advances in reducing tires environmental impact, although these have largely focused on end-of-life technologies and recycling.
Cox Enterprises’ Golden Isles Conservation Center, in Nahunta, Georgia, is using a waste management technology for the first time in the US that breaks down waste tires and produces synthesis oil, carbon black, synthesis gas and steel.
The technology, developed by Italian company Piromak, uses organic materials such as wood chips to generate heat, which breaks down tires into their original components.
By repurposing the materials, the Center has the capacity to daily remove the equivalent of 5 tons of tires from landfills and waterways, Cox says. The synthesis oil can be used as a substitute for many fuel-based products. The recovered carbon black can be used in products such as rubber hoses, inks, tires and plastics. Steel is the most recycled material on the planet and can be reused to make many new products. The synthesis gas generates heat for the closed-loop process.
Additionally, Bolder Industries (formerly Waste to Energy Partners), which produces a product using waste tires that is an alternative to carbon black, will this month open a new production facility that will diverting nearly 50 million pounds of waste from entering landfills each year and produce Bolder Black. The product can be used as a substitute for carbon black, an oil-derived component used in nearly all rubber and black plastic products.
