May 11, 2011

Iowa State's role in the future of biofuels | The Des Moines Register |

Ames, Ia. - Prototypes of the biofuels refinery of the future sit in a 19,000-square-foot complex on the Iowa State Research Farm west of Ames. Two experimental plants, whose network of pipes and containers looks to the lay person like a microbrewery on steroids, produce oil from biomass such as corn stover, switchgrass, miscanthus, wood chips and algae. One plant produces biocrude through a form of incineration called pyrolysis, which heats biomass to 1,000 degrees Fahrenheit in an oxygen-free environment and then decomposes the biomass to vapors and aerosols.

Rapid cooling then turns the vapors into bio-oil, which eventually could be refined into a fuel. Director Robert Brown of the Iowa State University Bioeconomy Institute likens pyrolysis to "taking the white smoke from a campfire, driving out particulates and separating different molecules to make bio-oil." The second prototype is a gasification plant, a process by which heat of up to 1,600 degrees Fahrenheit breaks down the biomass to its most basic elements to produce a synthetic gas.

A steam process turns the biomass into a synthetic gas. An interesting byproduct is the carbon waste, or "biochar" that drops out of the gasification process. "Biochar turns out to have value as a fertilizer," Brown said, and helps keep carbon in the soil and out of the atmosphere. The pyrolysis and gasification plants already have produced a variety of oils - some of which smell distinctly like barbecue sauce. Brown and his team are analyzing and experimenting for their potential as fuels for boilers, power plants, internal combustion engines and gas-turbine engines.
Corn ethanol was easy; next step much harder

The $23 million project was kicked off by a grant in 2007 from ConocoPhillips and aided by money from the U.S. Departments of Agriculture and Energy as well as Dupont (owner of Pioneer Hi-Bred) and Danisco. "What makes this facility one of a kind is that it isn't limited to a single biomass, but can take all biomass products for conversion to fuels," Brown said. When will the ISU labs produce a finished fuel? "You tell me the price of oil," Brown responds.

Brown's statement reflects the long experience of alternative energy: interest and research surge when oil prices rise. With oil prices near $100, prospects look good for a speedup in Brown's operation. Brown said the goal is to produce a usable biofuel by 2022. Brown asserts that the public has been given a somewhat misleading picture of biofuels by the explosive growth of traditional ethanol. It grew from less than 1 billion gallons of annual production in the middle of the last decade to almost 14 billion gallons this year, or 10 percent of U.S. annual gasoline consumption.

"Remember, it's taken us 40 years to get corn-fed ethanol up to 13 billion gallons of production annually," Brown said. "And that was with a technology that was long proven." Corn-fed ethanol production is a larger version of the backwoods corn fermentation process perfected long ago by moonshiners. "That was relatively easy," said Brown. "The next step will be harder." The challenge is daunting and the science yet incomplete. But Brown notes one advantage biomass fuels have over ethanol.

"Biomass can be made into oil in about five minutes," he said. "It takes to two days to ferment corn into ethanol." But moving to the next generation of biofuels depends in part on collecting enough biomass, and Iowa has plenty of corn stover - the cobs, leaves and stalks left behind after harvest.
Stover has logisticial, chemical challenges

Several experiments already have been conducted on Iowa cornfields to bale tons of stover for delivery to ethanol plants. The process requires special equipment and storage, and suffers from seasonality. Stover is most prevalent in October and November upon harvest and should be picked up immediately. There is another problem with stover beyond logistics. "Chemically, stover is tough because it's dirty," said Brown. "Stover picked up off the ground needs to be cleaned. The best way to harvest stover is to figure out a way to collect it without it hitting the ground."

Also, chemicals in the stover, such as nitrogen and potassium that make it so valuable as a soil additive, complicate the chemical process when stover is fed into Brown's biofuels makers. To clean up the corn stover, ISU scientists are investigating a process called hot vapor filtration. "The challenge we face is to remove those chemicals from the oil so that they don't dirty, so to speak, the fuel that ultimately is produced," Brown said.

How biofuels compare

CORN ETHANOL PROS: Lowest-cost biofuel. Producers are making improvements in efficiently. CONS: Ethanol is fast reaching market saturation at the current amounts at which it is added to gasoline. Ethanol has a lower energy content than gasoline and at higher levels can damage pumps and pollution-control equipment. Ethanol production also plays a role in increasing the the price of corn and the cost to consumers of meat and dairy products. Ethanol must be mixed with gasoline in cars. CELLULOSIC ETHANOL PROS: Can be made from a variety of feedstocks that aren’t used for food: crop residue, grasses and trees. CONS: Has the same drawbacks as corn ethanol and is more costly to produce. Cellulosic biorefineries would cost many times as much to build as corn ethanol plants. RENEWABLE GASOLINE, DIESEL AND JET FUEL PROS: Can be used just like conventional fuels and made from celluose as well as algae as well as from crops such as sugar cane. Renewable diesel already can be made from animal fats. CONS: Steep production and conversion costs.

Resarch farm is

The more exacting research is done on the northwest side of the ISU campus at the new $32 million state-funded biofuels research center. There, director Robert Brown brings together an intellectual dream team from ISU's engineering (chemical, mechanical, agricultural), chemistry, economics, agronomy, biology.

THE CHALLENGE The challenge is nothing less than to produce a fuel that will do for the 21st century what refined petroleum gasoline did for the world in the 20th century. Crude petroleum has proved difficult to dislodge as the premier transportation fuel because of its power and efficiency. Ethanol has only about two-thirds the heat, or energy-producing power, of conventional fossil fuels. THE PROBLEM A fundamental problem for any bio-oil is that it contains about 25 percent water, where fossil oil contains none. That means the flame from biooils will burn at different temperatures, which in turn requires different designs on combustion chambers and injection systems in engines. ROOM FOR IMPROVEMENT The most optimistic forecasts for biofuels show petroleum distillates still providing up to three-quarters of transportation energy by the middle of this century. But Brown reminds that crude oil once didn't burn efficiently. "When crude oil was first refined more than a century ago, it produced only about 2 percent of its total potential energy efficiency," Brown said. His labs are producing biofuels at 40 percent of its potential efficiency, he said. "The next 60 percent will be hard. But we can get there." - Dan Piller

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