Biomass Energy

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 ethanol per year from Cellulosic Biomass (> 10 billion tons biomass/yr).

Florida’s Inedible Biomass Feedstocks:

Municipal waste, green waste
Bagasse and sugarcane waste
Citrus pulp
Forest residues & thinnings
Invasive trees and plants
Animal waste
Agricultural residues
Energy crops from trees such as pines and hardwoods
Agricultural crops such as grasses, corn, sweet sorghum, and sweet potato.

Oilseed Energy Crops – Oil to Renewable Jet Fuel

Carinata (Ethiopian mustard), a nonfood oilseed brassica is a dedicated feedstock for renewable jet fuel, diesel and other bioproducts. In the southeastern United States carinata can be produced as a cool season crop covering millions of acres of winter fallow land. The meal from carinata seed can provide a high-protein feed source for livestock. These characteristics make carinata a promising cool season crop that provides agronomic, environmental and economic benefits to producers.

South East Partnership for Advanced Renewables from Carinata (SPARC) has a twofold mission of removing physical, environmental, economic and social constraints of regional Brassica carinata production as a renewable fuel, bioproducts and coproducts feedstock and ensuring stable markets for jet fuel and bioproducts through demonstration of enhanced value across the supply chain.

The partnership received $15million funding from USDA to deliver regionally-appropriate sustainable biomass feedstock for the production of alternative jet fuel in supply chain systems that may be linked to facilities in proximity to civilian or military aviation hubs.

Thermochemical Conversion of Biomass to Liquid Fuels

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.

The potential impact on agriculture and energy production in Florida are significant. The long term implications point to decreasing the dependence on imported oil and liquid fuels and the development of a flourishing renewable energy industry tailored specifically to take advantage of the unique biomass production and feedstock capacity available in US.

The conversion of low value biomass to high value clean burning liquid fuels such as gasoline or diesel has significant economic potential not just for Florida but for the nation as a whole. Florida has the unique advantage of being able to produce substantial amounts of biomass which can be considered as a renewable energy source with much less green house gas emissions associated with its use.

Besides growing the biomass, there are many existing additional sources that can be effectively utilized to make liquid fuels. These include: biomass produced from forest residues, municipal green waste, bagasse from the sugar cane industry, which is currently used as low grade fuel, agricultural residues such as citrus peels and animal waste.

For the first step of gasification of biomass, fluidized gasifiers are most commonly used. The gasification technology involves high temperature (600-900 ^oC). The syngas produced contains mostly H₂, CO, CO₂ and H₂O but with tars, ammonia and particulates as impurities. The impurities are the primary barrier for direct use of the gas in Fischer-Tropsch Synthesis (FTS). Therefore technology to reduce the production of these impurities is critical to the success of this conversion process.

The investigators at USF has been studying this problem and developed some novel approaches to address this issue. A novel proposed process utilizes a breakthrough development resulting from many years of research. Essentially CaO is used as a catalyst and sorbent to promote the production of H₂ while breaking up the tars and hence lowering particulate formation. This has been demonstrated on an experimental scale at the Clean Energy Research Center at USF.