Sludge Watch ==> Cutting greenhouse gases - biofuels

[Maureen Reilly]

Cutting greenhouse gases: Biofuels that don't involve food crops or 
microbial fermentation
03.jul.07
Science Daily


California researchers plan to make biofuels in a novel way that doesn't 
involve food crops or microbial fermentation. A new research effort 
involving three University of California campuses and West Biofuels LLC, 
will develop a prototype research reactor that will use steam, sand and 
catalysts to efficiently convert forest, urban, and agricultural 
"cellulosic" wastes that would otherwise go to landfills into alcohol that 
can be used as a gasoline additive.
"We have a very feasible design to combine individual components of 
technology that have been proven separately into a successful biomass 
processing prototype," said Robert Cattolica, leader of the research program 
and a professor of mechanical and aerospace engineering at UC San Diego's 
Jacobs School of Engineering. Cattolica is the principal investigator of the 
project, which includes researchers at UC San Diego, Davis, and Berkeley.
Since carbon dioxide is naturally recycled from the atmosphere into 
cellulose in plants and back into the atmosphere as carbon dioxide when 
plants decompose, burning biomass-derived fuel such as alcohol in internal 
combustion engines has a zero net effect on the amount of carbon dioxide in 
the atmosphere. On the other hand, burning fossil fuels continually adds 
carbon dioxide, a greenhouse gas, to the atmosphere.
The new biofuels research project was inspired by California's Global 
Warming Solutions Act, which was signed into law by Governor Arnold 
Schwarzenegger in September 2006. The act requires a 25 percent reduction in 
greenhouse gas emissions in California by 2025. Substituting biomass fuel 
for petroleum would help California achieve its goal. The two-year UC 
project is funded with a $1.85 million grant from West Biofuels LLC, a San 
Rafael, CA, company that is developing the biomass-to-alcohol technology, 
and a $1.15 million state-funded UC Discovery Grant.
"My company is excited about partnering with the University of California on 
a very promising technology that could eventually have a significant 
beneficial impact on our environment while also reducing California's 
reliance on oil imports," said Peter Paul, chief executive officer of West 
Biofuels.
The alcohol currently added to gasoline sold in California is derived from 
corn, sugar cane, beets, or other farm crops. About 95 percent of the 
alcohol additive comes from outside of California and as far away as China. 
Rather than fermenting food crops into ethanol, Cattolica's project will use 
a thermo chemical process to break down shredded cellulosic wastes into a 
mixed alcohol, predominately ethanol. "The technology we're developing will 
tap a huge, energy-rich resource that now is literally going to waste," said 
Cattolica.
The prototype reactor will mix the wastes with high temperature sand in a 
reaction chamber while the mixture is heated with steam. The gasification 
process generates an energy rich combination of hydrogen (H2), carbon 
monoxide (CO), methane (CH4), and carbon dioxide (CO2). Those gases will be 
catalytically "reformed" into alcohols. About 30 percent of the energy 
content of the starting material will be burned to supply the energy needed 
to operate the plant.
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."
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