04-12-2012, 04:34 PM
Biomass Energy
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INTRODUCTION
Biomass offers tremendous opportunity as a major, near-term, carbon-neutral energy resource. Florida has more biomass resources than any other state, ~7% of the U.S. total. As such, harnessing these resources should be a key component of Florida’s energy strategy. Efficient biomass conversion depends on locally available resources due to high shipping costs of biomass. Cellulosic ethanol and gasification processes are just entering the early commercial phase and offer many opportunities for improvement. These improvements are directed at reducing capital costs and facilitating commercial deployment, thus creating new industry and new employment for Florida. Florida could produce over 8 billion gallons (ask Lonnie if this figure is still good) ethanol per year from Cellulosic Biomass.
Cellulosic Ethanol from Biomass
Cellulosic ethanol is a biofuel produced from inedible parts (lignocellulose) of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin. Switchgrass, woodchips, sweet sorghum, orange peels are some of the more popular cellulosic materials for ethanol production. Cellulosic ethanol has the advantage of abundant and diverse raw material compared to sources like corn and cane sugars.
By using a variety of regional feedstocks for refining cellulosic ethanol, fuel can be produced in nearly every region of the country. Though it requires a more complex refining process, cellulosic ethanol contains more net energy and results in lower greenhouse emissions than traditional corn-based ethanol. E-85, an ethanol-fuel blend comprised of 85-percent ethanol, is already available in more than 1,000 fueling stations nationwide and can power millions of flexible fuel vehicles already on the roads.
1.3 Billion dry tons biomass/year produces 130 Billion gal of fuel ethanol or 1.0 Billion tons of chemicals or some combination.
Dr. Lonnie Ingram, Distinguished Professor of microbiology at UF and member of the National Academy of Sciences, has spent the last two decades inventing and refining what many believe is the most promising approach yet to converting all that plant waste material into cellulosic ethanol.
“The net positive energy from cellulosic energy has been estimated by the Department of Energy at about 85 percent, with 15 percent to grow crops, transport and produce,” Ingram says. “Corn is the exact opposite, 15 percent positive energy compared to 85 percent to grow the corn.”
Cellulosic ethanol is chemically identical to corn ethanol and offers all of the same benefits – renewable, clean-burning – without the massive energy requirement and food competition. And Florida is the nation’s biomass giant. Florida produces more biomass per year than any other state in the country. Estimates are that as much as 10 billion gallons of ethanol a year from biomass resources could be produced in Florida, and much of that would be from material that is currently going to landfills, like yard waste.”
Technology challenges in Thermochemical Conversion
Many of biomass products are rich in lignin and hence more suited to conversion via the thermochemical process as opposed to biochemical conversion. Unlike the thermochemical process, biochemical or fermentation processing of most cellulose biomass feed stocks have not yet been established. Additionally, thermochemical methods are faster and easier to control than biological methods.
In the thermochemical process, biomass feed stocks are first partially oxidized to form a mixture of carbon monoxide and hydrogen (syngas) and then converted to clean burning liquid hydrocarbon fuels ranging from ethanol, gasoline, kerosene, and diesel through JET A-1 or JP8 jet fuel. This is accomplished via the well known and established Fischer-Tropsch synthesis (FTS) process developed in Germany in 1920s and commercialized in South Africa during the 70s. The key technology development here is two-fold: (1) Tailoring the design of the gasifier to suit variety of biomass produced in Florida. This involves fine tuning of processing conditions (contact method, temperature, pressure, biomass to oxygen ratio etc.) to achieve optimum production of syngas while minimizing pollutant formation and maximizing energy production. (2) The design and optimization of the unique catalysts, reactors and processing conditions required for converting the syngas to meet the demands for a variety of liquid fuels.