Forget Petroleum: Pick Your Fuel of the Future

by David Hunt  

Researchers at North Carolina State University have developed a fuel refining process that could revolutionize America's energy industry. But not everything will change. You'll still fill up your car with gasoline, use propane for your barbecue grill and reach your favorite vacation spot in an airliner powered by jet fuel.

The revolution will happen at the molecular level. Simply put, NC State researchers have developed a process that enables them to take virtually any fat source and chemically alter it so that it looks, acts and burns just like petroleum-based fuel. 

"The process is flexible enough that we can make any fuel we want," says Dr. Bill Roberts, a professor of mechanical and aerospace engineering. "By changing the catalyst, temperature and pressure over time, we can make gasoline, diesel, heating oil, and even jet fuel."

It's not magic, Roberts says, it's chemistry.

In a not-too-distant future envisioned by Roberts, expect to see an oil refinery in Arizona, pumping out tens of thousands of gallons of gasoline for local consumers. But instead of importing crude oil from Saudi Arabia as its fuel source, the facility will use the simple fats harvested from plants.

"If we tie the refinery to an algae that we can grow in the desert in clear plastic tubes in salt water, then we have a feedstock supply that is renewable," he says. "Plus, that won't impact the food supply and drive up the cost of groceries."

In North Carolina, you may someday see processing facilities that use fats from animals, such as hogs and poultry.

The innovative process could help the U.S. reduce its dependence on foreign oil and – equally important – reduce its reliance on fossil fuels that emit greenhouse gases.

Dr. Henry Lamb with a vial of jet fuel made from animal fat. Centia is a registered trademark of Diversified Energy Corporation.

The chemistry expert on the project is Dr. Henry Lamb, a professor of chemical and biomolecular engineering at NC State. Lamb says the chemistry behind the process is fairly simple and has been used in petroleum refining for nearly a century. In fact, he sees physical and chemical similarities between crude oil and animal fat.

"If you look at crude oil, it's really viscous – almost solid at room temperature – and has chains of hydrocarbon molecules," he says. "If you look at a tub of lard, you have this thick, almost solid material that also has hydrocarbon chains."

In petroleum refining, engineers use chemicals, catalysts, heat, and pressure to separate and combine the basic types of hydrocarbon molecules naturally found in crude oil. Different processes result in different kinds of petroleum products. Gasoline typically contains hydrocarbons with between five and 12 carbon atoms per molecule.

The researchers believed that if they put animal fat through similar processes, they would wind up with similar molecules. The challenge – and the brilliance of their work – was to create a process that could start with any fat source and wind up with any type of fuel.

The team, which also included Dr. Larry Stikeleather, a professor of biological and agricultural engineering, and Timothy Turner, a doctoral student in mechanical engineering, developed a three-step process, elegant in its simplicity.

In the first step, the fat source – be it animal fat, waste grease, or oil from plants – is heated in a reactor vessel under pressure, causing the fat to break down. One byproduct, glycerol, is removed and used as a fuel source to help power the equipment. The remaining fat, which has been broken down to its simplest form, called free fatty acids, is now ready for step two. In this stage, the free fatty acids are again heated under pressure and passed through a catalyst, a kind of filter. The resulting liquid is made up of simple straight-chain hydrocarbons called alkanes.

In the third step, the alkanes are subjected to various catalysts and again heated under pressure to chemically reform them. Depending on the variables, the resulting product may be jet fuel, bio-gasoline, bio-diesel, or heating fuel. This stage is almost identical to the procedure called hydrocracking, which has been used to convert the hydrocarbons in crude oil into petroleum products for more than 70 years.

"This process is taking a page from the petroleum refining industry and applying it to a biofuel," says Lamb. "The beauty is that nothing has to change. You don't need to develop new engines or new pipelines. And you can blend our biofuels with conventional fuels."

Dr. Larry Stikeleather in his lab.

From an economic perspective, the process builds in an incredible amount of flexibility. If the price of one feedstock goes up, a fuel producer can switch to a more affordable source. Likewise, if the market for one type of fuel becomes weak, a refiner can begin producing another.

As revolutionary as the development is, the researchers recognize that their idea still has to be turned into a business. Last year they received the backing of industrialist and financier W. David Thompson, founder and chairman of Diversified Energy Corporation. The Arizona-based company has licensed the technology under the name Centia (a derivation of "green power" in Latin), and is raising capital to test and perfect the process.

"We have some of the best people in the world behind this," says Jeff H. Hassannia, the company's vice-president of business development. "We think the science is sound, but we need to scale it up and put it all together."

The company's initial goal is to develop a fully integrated model facility that can produce about 20,000 gallons of fuel a year on or near NC State's Raleigh campus. That could be up and running within 12 to 18 months following funding. Eventually, a large-scale plant could generate tens of millions of gallons a year. Of course, the market for renewable alternatives to petroleum is vast; North Carolina alone consumes 5.6 billion gallons of petroleum-based fuel every year – all of it imported from refineries outside the state.

"America's energy problem is so big, there isn't going to be a single solution," Hassannia says. "And we're not the only people working in the field; the competition is hot and heavy. But at the end of the day it comes down to commodity dynamics – supply and demand. That's where Centia's flexibility and economics make it very attractive."

Links:

• Teamwork: Great Minds Work Together

• 2008: The Year of Energy at NC State

• NC State Office of Technology Transfer

• Diversified Energy Corporation