Biomass to liquid (BtL or BMtL) is a multi-step process of producing synthetic

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...

fuels made from

biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...

via a thermochemical route.

Main processes

According to a study done by the

U.S. Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and production ...

and the

Department of Energy A ministry of energy or department of energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-rela ...

, the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

can produce at least 1.3 billion tons of cellulosic

each year without decreasing the amount of biomass needed for food, animal feed, or exports.

Fischer–Tropsch process

The

Fischer–Tropsch process The Fischer–Tropsch process (FT) is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen, known as syngas, into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at te ...

is used to produce synfuels from gasified biomass. Carbonaceous material is gasified and the gas is processed to make purified

syngas Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as ...

(a mixture of

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

and

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

). The Fischer–Tropsch polymerizes syngas into

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...

-range hydrocarbons. While

biodiesel Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats. The roots of bi ...

and

bio-ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an alcohol, with its formula also written as , or EtOH, where Et is the pseudoelement symbol f ...

production so far only use parts of a

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

, i.e.

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecul ...

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

, BtL production can gasify and utilize the entire plant.

Flash pyrolysis

Flash

pyrolysis Pyrolysis is a process involving the Bond cleavage, separation of covalent bonds in organic matter by thermal decomposition within an Chemically inert, inert environment without oxygen. Etymology The word ''pyrolysis'' is coined from the Gree ...

—producing bio-oil (

pyrolysis oil Pyrolysis oil, sometimes also known as biocrude or bio-oil, is a synthetic fuel with few industrial applications and under investigation as substitute for petroleum. It is obtained by heating dried biomass without oxygen in a reactor at a temper ...

), char and gas at temperatures between 350 and 550 °C and residence times < 1 second (also called anhydrous pyrolysis).

Catalytic fast pyrolysis

Catalytic fast pyrolysis is a fast process in which the

is broken down to a liquid biofuel. In this approach the cellulose is heated to 500 degrees

Celsius The degree Celsius is the unit of temperature on the Celsius temperature scale "Celsius temperature scale, also called centigrade temperature scale, scale based on 0 ° for the melting point of water and 100 ° for the boiling point ...

in less than one second in a chamber to break apart the molecules. The catalyst forms

chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

s that remove oxygen bonds and form

carbon ring In organic chemistry, an alicyclic compound contains one or more all-carbon Cyclic compound, rings which may be either Saturated and unsaturated compounds, saturated or unsaturated, but do not have aromaticity, aromatic character. Alicyclic compo ...

s. After the reaction takes place gasoline is formed along with water,

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

, and

Pyrolysis and gasification

Initially biomass undergoes

process to produce pyrolysis gases and

biochar Biochar is a form of charcoal, sometimes modified, that is intended for organic use, as in soil. It is the lightweight black remnants remaining after the pyrolysis of biomass, consisting of carbon and ashes. Despite its name, biochar is steril ...

. The

volatile organic compounds Volatile organic compounds (VOCs) are organic compounds that have a high vapor pressure at room temperature. They are common and exist in a variety of settings and products, not limited to house mold, upholstered furniture, arts and crafts sup ...

in pyrolysis gases further undergo

gasification Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (). This is achieved by reacting ...

process to produce

rich in

and

gases which is further converted in to

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

(CH₃OH). The carbon neutral biochar is further converted in to

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon–carbon bond, carbon–carbon doub ...

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

with hydrogen generated from renewable electricity or used for

carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. It plays a crucial role in Climate change mitigation, limiting climate change by reducing the amount of Carbon dioxide in Earth's atmosphere, carbon dioxide in the atmosphe ...

to reduce global warming CO₂ gas in the atmosphere.

Potential energy grasses

Fuel from energy grasses may be referred to as ''grassoline''.

Switchgrass

Switchgrass ''Panicum virgatum'', commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55th parallel north, 55°N latitude in Canada southwards into the United States and Mexico. Switch ...

is a

bunch grass Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennia ...

native to North America that grows naturally in warm weather with wide adaptation capability and easy

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ...

, allowing the switchgrass to grow faster; however, it has a low relative yield compared to other energy crops

Sorghum

Sorghum ''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain i ...

'' is cultivated in warmer climates, mostly in the tropical regions. ''Sorghum'' has the potential to be an energy grass because it requires little water and can give a large yield. ''Sorghum'', however, is an annual plant, is difficult to establish in an area, and requires a large input of fertilizers and pesticides.

Miscanthus

Miscanthus ''Miscanthus'', or silvergrass'','' is a genus of African, Eurasian, and Pacific Island plants in the grass family, Poaceae. The name is derived from the Greek words "''miskos"'', meaning "stem", and "''anthos"'', meaning "flower", in reference ...

'' species are native to the

tropical regions The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

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

Sugarcane

Sugarcane Sugarcane or sugar cane is a species of tall, Perennial plant, perennial grass (in the genus ''Saccharum'', tribe Andropogoneae) that is used for sugar Sugar industry, production. The plants are 2–6 m (6–20 ft) tall with stout, jointed, fib ...

'' grows in irrigated lands of tropics and

subtropics The subtropical zones or subtropics are geographical and climate zones immediately to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately ...

which can produce 15 kg biomass per square meter area. It is also suitable for BtL as its extracted juice is used to produce ethanol by traditional methods and also its remaining biomass (bagasse, leaves, shoots, etc.) can be converted in to carbon neutral

by subjecting to

and

Biochar Biochar is a form of charcoal, sometimes modified, that is intended for organic use, as in soil. It is the lightweight black remnants remaining after the pyrolysis of biomass, consisting of carbon and ashes. Despite its name, biochar is steril ...

can also be produced for

to compensate the carbon emissions by fossil fuels or reduce CO₂ gas concentration in the atmosphere.

Bamboo

Bamboo is one of the fastest growing plant/biomass which can be used as feed stock for BtL. Most bamboo species are native to warm and moist tropical and to warm temperate climates. However, many species are found in diverse climates, ranging from hot tropical regions to cool mountainous regions and highland

cloud forests A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest, is a generally tropical or subtropical, evergreen, montane, moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, ...

Cost of change

Fuel costs depend on how fast the grasses grow and other factors. An estimated investment of over $325 billion (2008 basis) would be needed to build biofactories capable of producing the 65 billion gallons of biofuel needed to meet 2030 national goals.

References

* {{cite journal , last1 = Khodakov , first1 = Andrei Y. , last2 = Chu , first2 = Wei , last3 = Fongarland , first3 = Pascal , year = 2007 , title = Advances in the Development of Novel Cobalt Fischer-Tropsch Catalysts for Synthesis of Long-Chain Hydrocarbons and Clean Fuels , journal = Chemical Reviews , volume = 107 , issue = 5, pages = 1692–1744 , doi = 10.1021/cr050972v , pmid = 17488058

External links

EUROBIOREF : European Multilevel Integrated Biorefinery Design for Sustainable Biomass Processing

SWAFEA : Sustainable Way for Alternative Fuels and Energy for Aviation

at

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

FAS website
Enzymatic Hydrolysis
at DOE EERE website
NSF article on the work of Huber and others towards plant based fuel
Biomass Synthetic fuel technologies Fuel production