Biomass to liquid

Biomass to liquid (BtL or BMtL) is a multi-step process of producing synthetic hydrocarbon fuels made from biomass via a thermochemical route. Such a fuel has been called grassoline.

Main processes
According to a study done by the U.S. Department of Agriculture and the Department of Energy, the United States can produce at least 1.3 billion tons of cellulosic biomass each year without decreasing the amount of biomass needed for our food, animal feed, or exports.

Fischer–Tropsch process
The Fischer–Tropsch process is used to produce synfuels from gasified biomass. Carbonaceous material is gasified and the gas is processed to make purified syngas (a mixture of carbon monoxide and hydrogen). The Fischer–Tropsch polymerizes syngas into diesel-range hydrocarbons. While biodiesel and bio-ethanol production so far only use parts of a plant, i.e. oil, sugar, starch or cellulose, BtL production can gasify and utilize the entire plant.

Flash pyrolysis
Flash pyrolysis—producing bio-oil (pyrolysis oil), char and gas at temperatures between 350–550 °C and residence times < 1 second (also called anhydrous pyrolysis).

Catalytic fast pyrolysis 
Catalytic fast pyrolysis is a fast process in which the cellulose is broken down to a liquid biofuel. In this approach the cellulose is heated to 500 degrees Celsius in less than one second in a chamber to break apart the oxygen molecules. The catalyst forms chemical reactions that remove oxygen bonds and form carbon rings. After the reaction takes place gasoline is formed along with water, carbon dioxide, and carbon monoxide.

AFEX treatment 
The Ammonia Fiber Expansion (AFEX) pre-treat process, hot concentrated 15 M ammonia is used to break down sugar molecules, cellulose and hemicellulose significantly more efficiently than enzymes. After, the rapid pressure release cools and ends the treatment. The result is minor biomass degradation with high yields. The process was patented by Bruce Dale, Michigan State University professor. AFEX is generally done in one step, making it more efficient than other processes.
AFEX Process Conditions
 Pressure: 20–30 atm
 Temperature: 70–140 C
 Residence time: 5–10 minutes
 Ammonia: biomass loading: 0.3 – 2.0 to 1 w/w
 Water: biomass content: 0.2 – 2.5 to 1 w/w

Catalytic depolymerization
Catalytic depolymerization is the use of heat and catalysts to separate usable diesel fuel from hydrocarbon wastes.

Regional Biomass Processing Center 
Regional Biomass Processing Center is a conceptual place where the AFEX treated biomass can go to biorefineries, farms and forests, and animal feeders. This will improve the value of cellulosic biomass for animals and biofuel production. This will reduce the density of the biomass for easier transport, simplify contract issues, and increase the land use for biofuels

The process uses the whole plant to improve the carbon dioxide balance and increase yield.

Potential energy grasses
Plant material is cheaper than oil on both energy and mass basis and certain plant material have potential to be energy grasses.

Switchgrass 
Switchgrass is a bunch grass native to North America that grow naturally under warm weather with wide adaptation capability and easy germination, allowing the switchgrass to grow quicker; however, it has a low relative yield compared to other energy crops

Sorghum 
Sorghum are cultivated in warmer climates, mostly in the tropical regions. Sorghum has the potential to be an energy grass because it requires low water usage and can make a large yield. Sorghum, however, has an annual cultivation and is difficult to establish to an area and requires a lot of input from fertilizers and pesticides.

Miscanthus 
Miscanthus are native to the tropical regions of Africa and Southern Asia. Miscanthus can grow up to 3.5 meters and has been trialed as a biofuel since the 1980s. The benefits of using miscanthus is it can live more than two years and requires low input eliminating the need for extra irrigation, fertilizer and pesticides. The problems with miscanthus arise from the time it takes to establish to an area.

Grassoline
Grassoline is a term coined in 1991 by Matthew Scoggins, a graduate student of Bruce Dale, to capture the idea of taking plant material and converting it into oil.

Cost of change 
The cost for petroleum to change to grassoline would depend on how fast the use of grassoline grows. Change will also be needed in automobiles to be compatible with grassoline. UC Berkeley's Somerville (professor of alternative energy) estimates that a large investment over $325 billion will be needed to build biofactories that can produce the 65 billion gallons of biofuel needed to meet 2030 national goals.

See also

Bioconversion of biomass to mixed alcohol fuels
Bioenergy
Biofuel
Bioliquids
Biomass
Biomass gasification
Biomass heating systems
Bioproduct
Biorefinery
Coal to liquid
DMF fuel
Gas to liquid
Gasification
NExBTL—despite the name BtL, the feedstock is plant oil, not whole plants.
Non-food crops
Renewable energy
Sustainable energy
Synthetic fuel
Thermal depolymerization
Vegetable oil refining
Wood fuel

References

External links
 EUROBIOREF : European Multilevel Integrated Biorefinery Design for Sustainable Biomass Processing
 SWAFEA : Sustainable Way for Alternative Fuels and Energy for Aviation
 "Synthetic Diesel May Play a Significant Role as Renewable Fuel in Germany" at USDA FAS website
 Enzymatic Hydrolysis at DOE EERE website
 NSF article on the work of Huber and others towards plant based fuel

Category:Biomass
Category:Synthetic fuel technologies
Category:Fuel production