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.[1] 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.[2]

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.[2]

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.[3] AFEX is generally done in one step, making it more efficient than other processes.

AFEX Process Conditions[4]

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[4]

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.[4]

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.[4]

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.[5]

Cost of change

The cost for petroleum to change to grassoline would depend on how fast the use of grassoline grows.[2] 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.[6]

See also

References
  1. Biomass to liquid term
  2. Huber, George W. "Grassoline at the Pump". Scientific American. PMID 19555024.
  3. Dale, Bruce E. "AFEX Pre-treatment Process Can Reduce Cost of Cellulosic Ethanol".
  4. Dale, Bruce E. "GRASSOLINE IN YOUR TANK: WHY CELLULOSIC ETHANOL IS NEARER THAN YOU THINK" (PDF). Archived from the original (PDF) on 13 November 2013. Retrieved 11 November 2013.
  5. Schmuhl, Emily (2 December 2009). "'Grassoline' is the future for spotlighted LDS scientists". Mormon Times.
  6. Dale, B.E. (2008). "Grassoline in Your Tank: Myths and Realities about Biofuels". Microscopy and Microanalysis. 14: 1484–1485. doi:10.1017/s1431927608088764.
  • Khodakov, Andrei Y.; Chu, Wei; Fongarland, Pascal (2007). "Advances in the Development of Novel Cobalt Fischer-Tropsch Catalysts for Synthesis of Long-Chain Hydrocarbons and Clean Fuels". Chemical Reviews. 107 (5): 1692–1744. doi:10.1021/cr050972v. PMID 17488058.
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