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 hydrophobic, and their odors are usually weak or ...

fuels made from biomass 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 the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of comme ...

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-re ...

, the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

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 The Fischer–Tropsch process 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 temperatu ...

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

and

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

). The Fischer–Tropsch polymerizes syngas into diesel-range hydrocarbons. While

biodiesel Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oil ...

and

bio-ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

production so far only use parts of a

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

, i.e.

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

, sugar, starch or

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...

, BtL production can gasify and utilize the entire plant.

Flash pyrolysis

Flash

pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...

—producing bio-oil (

pyrolysis oil Pyrolysis oil, sometimes also known as bio-crude or bio-oil, is a synthetic fuel under investigation as substitute for petroleum. It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about with subsequent coo ...

), 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

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 molecules. The catalyst forms

chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...

s that remove oxygen bonds and form

carbon ring In organic chemistry, an alicyclic compound contains one or more all-carbon rings which may be either saturated or unsaturated, but do not have aromatic character. Alicyclic compounds may have one or more aliphatic side chains attached. The ...

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

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

, and

Pyrolysis and gasification

Initially biomass undergoes

process to produce pyrolysis gases and

biochar Biochar is the lightweight black residue, made of carbon and ashes, remaining after the pyrolysis of biomass. Biochar is defined by the International Biochar Initiative as "the solid material obtained from the thermochemical conversion of ...

. The

volatile organic compounds Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a t ...

in pyrolysis gases further undergo gasification process to produce syngas rich in

and

gases which is further converted in to methanol (CH₃OH). The carbon neutral biochar is further converted in to ethylene or

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

with hydrogen generated from renewable electricity or used for

carbon sequestration Carbon sequestration is the process of storing carbon in a carbon pool. Carbon dioxide () is naturally captured from the atmosphere through biological, chemical, and physical processes. These changes can be accelerated through changes in lan ...

to reduce global warming CO₂ gas in the atmosphere.

AFEX treatment

In the Ammonia Fiber Expansion / Explosion (AFEX) pre-treat process, hot concentrated 15 M

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

is used to break down sugar molecules,

and

hemicellulose A hemicellulose (also known as polyose) is one of a number of heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all terrestrial plant cell walls.Scheller HV, Ulvskov Hemicelluloses.// Annu Rev ...

significantly more efficiently than enzymes. The result is minor biomass degradation with high yields. AFEX is generally done in one step, making it more efficient than other processes.

Catalytic depolymerization

Catalytic Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

depolymerization Depolymerization (or depolymerisation) is the process of converting a polymer into a monomer or a mixture of monomers. This process is driven by an increase in entropy. Ceiling temperature The tendency of polymers to depolymerize is indicated by ...

is the use of heat and catalysts to separate usable diesel fuel from

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

balance and increase yield.

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 55°N latitude in Canada southwards into the United States and Mexico. Switchgrass is one of the ...

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

Sorghum

'' Sorghum'' 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. ; Species * '' Miscanthus changii'' Y.N.Lee – Korea * '' Miscanthus depauperatus'' Merr. – the Philippines * '' Miscant ...

'' species are native to the

tropical regions The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

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'' grows in irrigated lands of tropics and subtropics 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

or methanol by subjecting to

and gasification.

Biochar Biochar is the lightweight black residue, made of carbon and ashes, remaining after the pyrolysis of biomass. Biochar is defined by the International Biochar Initiative as "the solid material obtained from the thermochemical conversion of ...

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.

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 The name biofactory comes from the improvements which different installments of traditional health services ( wastewater treatment and water treatment plants) have been through; this has been done by reassessing them into a Circular Economy (CE). ...

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 the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...

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