Apr 9 2008
George Huber of the University of Massachusetts Amherst has received a $400,000 CAREER grant from the National Science Foundation to pursue his revolutionary new method for making biofuels, or "green gasoline," from wood or grasses, a process that would be much less expensive than conventional gasoline or ethanol made from corn.
Results of Huber’s research were published in the April 2008 issue of ChemSusChem, a publication devoted to environmentally-sound chemistry.
“We’ve proven this method on a small scale in the lab,” says Huber, a professor of chemical engineering. “But we need to make further improvements and prove it on a large scale before it’s going to be economically viable.”
Huber is a nationally recognized expert on biofuels, which are sustainable fuels made from plant materials. In June 2007, he chaired a workshop in Washington, D.C., for the National Science Foundation and the U. S. Department of Energy titled “Breaking the Chemical & Engineering Barriers to Lignocellulosic Biofuels,” which was attended by 71 top experts from academia, industry and governmental agencies.
Huber’s method is for making biofuels from cellulose, the non-edible portion of plant biomass and a major component of grasses and wood. At $10 to $30 per barrel of oil energy equivalent, cellulosic biomass is significantly cheaper than crude oil. The U.S. could potentially produce 1.3 billion dry tons of cellulosic biomass per year, which has the energy content of four billion barrels of crude oil. That’s more than half of the seven billion barrels of crude oil consumed in our country each year. What’s more, biomass as an energy crop could increase the national farm income by $3 to $6 billion per year.
Huber is addressing the lack of an economical process for converting cellulose into liquid biofuels, which is the main roadblock for their mass production. Every conventional conversion method takes several steps, with each step making the whole process more expensive and less feasible. For example, ethanol production from cellulosic biomass currently involves multiple steps, including pretreatment, enzymatic or acid hydrolysis, fermentation, and distillation. Other processes for making biofuels have been hamstrung by similar multi-step methods.
Huber has come up with a technique for producing his “green gasoline” from biomass in one simple step by placing solid biomass feedstocks such as wood in a reactor, which is basically a high-tech still for thermal conversion of feedstock to gasoline. He heats the feedstock by a technique known as catalytic fast pyrolysis, which means the rapid heating of the biomass to between 400 and 600 degrees centigrade, followed by quick cooling. By adding zeolite catalysts to this process, gasoline range hydrocarbons can be directly produced from cellulose within sixty seconds.
“This is a big improvement because it’s all done in one single step, instead of several stages,” explains Huber. “Also, because of the high temperatures we use in the process, the residence time in our reactor is two to 60 seconds. With cellulosic ethanol, your residence time is five to ten days, which means you have to have a huge reactor costing much more money. So we estimate that building a facility to use our process would be much less expensive.”
Using the current cost of wood in Massachusetts, which is $40 per dry ton, as an example of the feedstock he can use in this process, Huber estimates that a gallon of green gasoline can be produced with his method for between $1 and $1.70, depending on how much he can improve the catalytic conversion in his process through standard engineering techniques.
Huber has already demonstrated that this process will work on a small scale in his lab. Now he has to design a reactor and catalysts that are specifically geared for his process. Huber just received a $30,000 grant from the UMass Amherst Office of Commercial Ventures and Intellectual Property, as funded by the UMass president’s office, to develop a prototype reactor to demonstrate green gasoline production on a large scale.
Huber has been working with three other professors at UMass Amherst including Phillip R. Westmoreland, a chemical engineer and expert on fast pyrolisis who has been helping to design the reactor, and William C. Conner, a chemical engineer with expertise in zeolite catalysts. The third researcher is Scott Auerbach, a theoretical chemist from the UMass Amherst chemistry department.