Cutting greenhouse gases: wood chips in, alcohol out

This will actually include a three-step process. First, the biomass will be gasified thermochemically in a process that is widely used around the world to process wood, coal, and other carbon-containing materials into a “producer gas.” The methane in producer gas is typically burned to power electricity-generating power plants. However, the new reactor will catalytically “reform” the producer it into syngas, a mixture of hydrogen gas and carbon monoxide. In the final step, the syngas will be catalytically converted into mixed alcohols with a “synthesis” catalyst similar to one developed in the late 1980s by Dow Chemical Company.

In order for all the processes to run at maximum efficiently, the researchers will make use of highly sensitive laser sensors developed at UCSD to continuously monitor the entire operation. Process-control algorithms under development at UCSD’s Center for Control Systems and Dynamics (CCSD) will use the sensor data to continuously fine-tune steam temperatures and flows, gas mixtures, and catalyst regeneration to achieve the most efficient and reliable conversion of the biomass into fuel.

Cattolica’s team, which includes nine UC professors and seven post-doctoral fellows, will conduct research on a $1 million, 4-ton-per-day reactor. West Biofuels is building the reactor and will donate it to the University of California. Lessons learned will be incorporated into a 100-ton-per-day pilot plant, which could generate one 10,000-gallon tanker truck of mixed-alcohol fuel for every seven semi-tractor trailer trucks of biomass waste. California generates a huge volume of such wastes.

The Orange County basin alone produces about 30,000 tons of urban green wastes per day, which is simply dumped at landfills and used as compost. Cattolica said that waste supply could generate 3 million gallons per day of mixed-alcohol fuel, which is equivalent to all the ethanol currently added to California gasoline.

The biomass processing technology could also permit California to reduce its dependence on outside sources of ethanol. Motorists in California currently purchase more than 900 million gallons of ethanol a year, or 25 percent of the national total. However, the state produces only about 5 percent of the ethanol fuel it consumes. Schwarzengger issued an executive order in 2006 that requires the state to produce at least 20 percent of its biofuels by 2010, 40 percent by 2020, and 75 percent by 2050.

Cattolica said green wastes generated in San Diego and the Los Angeles and San Francisco Bay areas represent a huge untapped energy resource.

“The more paper and cardboard, agricultural and forest wastes, and sludge and municipal solid waste that we can process into biofuels the sooner the state can meet the state’s biofuels goals,” said Cattolica. “This is all attainable, and it will allow us to continue using internal combustion engines, reduce our dependence on fossil fuels, and reduce the production of greenhouse gases.”