Kitchen to Car: USDA backs BSE professor's method for producing eco-friendly biolubricants from waste cooking oil

Published: Jul 11, 2023 10:00 AM

By Jeremy Henderson

High triglycerides — bad for your heart, good for your engine (and your environment).

That's the (general) idea behind a novel method to produce eco-friendly biolubricants from waste cooking oil (WCO) to serve as base oil in automotive lubricants developed by Hossein Jahromi, an assistant research professor in the Department of Biosystems Engineering. And it's a good one.

The United States Department of Agriculture's National Institute of Food and Agriculture (NIFA) believes in it to the tune of $650,000; Auburn University’s Intellectual Properties Exchange is backing it with a full patent application.

Given the White House's mandate to achieve net-zero transportation sector emissions by 2050, the timing couldn't be better. Because, it turns out, investing in renewable fuel like biodiesel is only half the environmental battle.

"Even if the transportation sector transitions entirely to renewable fuels, this sector still uses petroleum-based lubricants that contribute significantly to carbon emissions," Jahromi said.

Currently, there are 75 biodiesel plants in the U.S. that produce nearly 2 billion gallons of biodiesel each year. Eighty percent of that yield is made from vegetable oils; only 13% is WCO.

"That leaves approximately 2.6 billion gallons of unutilized or underutilized WCO that could be available for biolubricant production each year," Jahromi said. "That could fill tanker trucks bumper-to-bumper from San Francisco to Washington D.C. and back."

That tremendous untapped resource, Jahromi says, not only has the theoretical net-zero emission benefit of traditional biodiesel but also the potential to become carbon-negative, because lubricants possess inherently lower emission than fuels.

"Base oils are key components of commercially formulated lubricants and account for up to 75-80% of lubricant cost," Jahromi said. "However, most of the current base oils are petroleum-based. WCO, on the other hand, consists of triglycerides, long chain fatty acids and oxidation products, their molecular size and carbon chain length making them a suitable raw material for lubricant production. Additionally, WCO has a higher polarity than fresh vegetable oils because of the presence of oxidation products."

What WCO doesn't currently have is a real, sustainable capacity for conversion into molecules with suitable viscosity, pour point, oxidation stability and response to additives. That, says Jahromi, is one issue that has so far kept the car to kitchen approach from producing marketable biolubricants.

"But previous development efforts, which have mostly been adapted from biodiesel production technologies, have also been unsuccessful in meeting all the mentioned requirements at the same time," he said. "In this project, we are leveraging existing technologies to develop a unique process that achieves the production of biolubricants from WCO while meeting all the specified properties simultaneously. Overall, this work will significantly improve the economy by adding value to a major agriculturally derived waste and help preserve the environment from a large portion of petroleum contaminants."

The title of the NIFA project is "Eco-Friendly Biolubricant Production from Waste Cooking Oil Using Integrated Catalytic Processes." Jahromi is principal investor; co-principal investigators are Sushil Adhikari, director of the Center for Bioenergy and Bioproducts; associate biosystems engineering professor Brendan Higgins; and Robert Jackson, Albert Smith Jr. Professor of Mechanical Engineering.

Media Contact: Jeremy Henderson, jdh0123@auburn.edu, 3334-844-3591