Glossary of Terms

A vocabulary of glossary terms.

a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z

Acetic Acid: An acid with the structure of C2H4O2. Acetyl groups are bound through an ester linkage to hemicellulose chains, especially xylans, in wood and other plants. The natural moisture present in plants hydrolyzes the acetyl groups to acetic acid, particularly at elevated temperatures.
Acid: Any of a class of substances whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals to form salts. A substance that yields hydrogen ions when dissolved in water. A substance that can act as a proton donor.
Acid Detergent Fiber: Organic matter that is not solubilized after 1 hour of refluxing in an acid detergent of cetyltrimethylammonium bromide in 1N sulfuric acid. ADF includes cellulose and lignin. This analytical method is commonly used in the feed and fiber industries.
Acid Hydrolysis: A chemical process in which acid is used to convert cellulose or starch to sugar.
Acid Insoluble Lignin: Lignin is mostly insoluble in mineral acids, and therefore can be analyzed gravimetrically after hydrolyzing the cellulose and hemicellulose fractions of the biomass with sulfuric acid. ASTM E-1721-95 describes the standard method for determining acid insoluble lignin in biomass.
Acid Soluble Lignin: A small fraction of the lignin in a biomass sample is solubilized during the hydrolysis process of the acid insoluble lignin method. This lignin fraction is referred to as acid soluble lignin and may be quantified my ultraviolet spectroscopy.
ADF: Organic matter that is not solubilized after 1 hour of refluxing in an acid detergent of cetyltrimethylammonium bromide in 1N sulfuric acid. ADF includes cellulose and lignin. This analytical method is commonly used in the feed and fiber industries.
AGE 85: Aviation Grade Ethanol used in piston engine aircraft. This fuel contains 85% Ethanol along with light hydrocarbons and biodiesel fuel.
Agitator: A device such as a stirrer that provides complete mixing and uniform dispersion of all components in a mixture. Agitators are generally used continuously during the cooking process and intermittently during fermentation.
Agricultural Residue: Agricultural crop residues are the plant parts, primarily stalks and leaves, not removed from the fields with the primary food or fiber product. Examples include corn stover 9stalks, leaves, husks, and cobs); wheat straw; and rice straw.
Air Quality Maintenance Area: Specific populates area where air quality is a problem for one or more pollutants.
Alcohol: A general class of hydrocarbons that contain a hydroxyl group (OH). The term "alcohol" is often used interchangeably with the term "ethanol," even though there are many types of alcohol. (See Butanol, Ethanol, Methanol.)
Aldoses: Occur when the carbonyl group of a monosaccharide is an aldehyde.
Algae: Primitive plants, usually aquatic, capable of synthesizing their own food by photosynthesis. Algae is currently being investigated as a possible feedstock for production in biodiesel, jet fuel, and other bioproducts.
Aliphatic: Any non-aromatic organic compound having an open chain structure.
Alkali: A soluble mineral salt.
Alkali Lignin: Lignin obtained by acidification of an alkaline extract of wood.
Alloy: Any large number of substances having metallic properties and consisting of two or more elements; with few exceptions, the components are usually metallic elements.
Alternative Fuel: As defined in the Energy Policy Act of 1992 (EPACT): methanol, denatured ethanol and other alcohols, separately or in blends of at least 10% by volume with gasoline or other fuels; compressed natural gas; liquefied natural gas, liquefied propane gas, hydrogen, coal derived liquid fuels, fuels other than alcohols derived from biological materials, electricity, biodiesel, and any other fuel deemed to be substantially not petroleum and yielding potential energy security benefits and substantial environmental benefits.
Ambient Air Quality: The condition of the air in the surrounding environment.
American Society for Testing and Materials: An international voluntary standards organization that develops and produces technical standards for materials, products, systems and services.
aMW: Average Megawatt. One megawatt of capacity produced continuously over a period of one year. 1aMW = 1MW x 8760 hours/year = 8,760 MWh = 8,760,000 kWh.
Anaerobic: Life or biological processes that occur in the absence of oxygen.
Anaerobic Digestion: A biochemical process by which organic matter is decomposed by bacteria in the absence of oxygen, producing methane and other byproducts.
Anhydrous: A compound that does not contain water.
Aquatic Plants: The wide variety of aquatic biomass resources, such a algae, giant kelp, other seaweed, and water hyacinth. Certain microalgae can produce hydrogen and oxygen while others manufacture hydrocarbons and a host of other products. Microalgae examples include Chlorella, Dunaliella, and Euglena.
Arabinan: The polymer of arabinose with a repeating unit of C5H804. Can be hydrolyzed to arabinose.
Arabinose: A five-carbon sugar C5H1005. A product of hydrolysis of arabinan found in the hemicellulose fraction of biomass.
Aromatic: Any organic compound containing de-localized electrons in a ring structure - e.g. benzene and benzoic acid. Aromatics have strong, characteristic odors.
ASTM: An international voluntary standards organization that develops and produces technical standards for materials, products, systems and services.
Atmospheric Pressure: Pressure of the air and atmosphere surrounding us which changed from day to day. It is equal to 14.7 psia.
Attainment Area: A geographic region where the concentration of a specific air pollutant does not exceed federal standards.
Auger: A rotating, screw-type sevice that moves material through a cylinder.
Available Production Capacity: The biodiesel production capacity of refining facilities that are not specifically designed to produce biodiesel.
Average Megawatt: (MWa or aMW) One megawatt of capacity produced continuously over a period of one year. 1aMW = 1MW x 8760 hours/year = 8,760 MWh = 8,760,000 kWh.
B100: Pure biodiesel.
See also: Proof
Background Level: The average amount of a substance present in the environment. Originally referring to naturally occurring phenomena. Used in toxic substance monitoring.
Backup Electricity: Power or services needed occasionally; for example, when on-site generation equipment fails.
Backup Rate: A utility charge for providing occadional electricity service to replace on-site generation.
Baffle Chamber: In incinerator design, a chamber designed to settle fly ash and coarse particulate matter by changing the direction and reducing the velocity of the combustion gases.
Bagasse: A sugarcane waste currently used for as a feedstock for producing ethanol.
Bark: The outer protective layer of a tree outside the cambium comprising the inner bark and the outer bark. The inner bark is a layer of living bark that separates the outer bark from the cambium and in a living tree is generally soft and moist. the outer bark is a layer of dead bark that forms the exterior surface if the tree stem. The outer bark is frequently dry and corky.
Barrel of Oil Equivalent: A unit of energy equal to the amount of energy contained in a barrel of crude oil. Approximately 5.78 million Btu or 1,700 kWh. One barrel = 5.6 cubic feet or .159 cubic meters; for crude oil, one barrel is about .136 metric tons, .134 long tons, and .150 short tons. A barrel is a liquid measure equal to 42 gallons or about 306 pounds.
Base: A classification of substances which when combined with an acid will form a salt plus water, usually producing hydroxide ions when dissolved.
Baseload Capacity: The power output that generating equipment can continuously produce.
Baseload Demand: The minimum demand experienced by an electric utility, usually 30-40% of the utility's peak demand.
Batch Distillation: A process in which the liquid feed is placed in a single container and the entire volume in=s heated, in contrast to continuous distillation in which the liquid is fed continuously through the still.
Batch Fermentation: Fermentation conducted from start to finish in a single vessel.
Batch Process: Unit operation where one cycle of feedstock preparation, cooking, fermentation and distillation is completed before the next cycle is started.
BATF: Bureau of Alcohol, Tobacco, and Firearms. Under the U.S. Department of Treasury. Responsible for the issuance of permits, both experimental and commercial, for the production of alcohol.
Beer Still: The stripping section of a distillation column for concentrating ethanol.
Benzene: A toxic, six-carbon aromatic component of gasoline. A known carcinogen.
Bio-based: Derived from biological materials.
Bio-Naphtha: A term used in some eastern European nations for biodiesel.
Bioaccumulation: Also Bioconcentration. The accumulation of a chemical in tissues of an organism to levels greater than in the environment in which the organism lives.
Biobased: Derived from biological materials.
Biobutanol: An advanced biofuel that offers a number of benefits over conventional biofuels. Biobutanol has an energy content closer to that of petroleum. It can easily be added to conventional gasoline due to low vapor pressure and can be blended at higher concentrations than ethanol for use in standard vehicle engines.
Biochemical Conversion Process: The use of living organisms or their products to convert organic material to fuels, chemicals or other products.
Biochemical Oxygen Demand: BOD. A standard means of estimating the degree of water pollution, especially of water bodies that receive contamination from sewage and industrial waste. BOD is the mount of oxygen needed by bacteria and other microorganisms to decompose organic matter in water. The greater the BOD, the greater the degree of pollution. Biochemical oxygen demand is a process that occurs over a period of time and is commonly measured for a five-day period, referred to as BOD5.
See also: BOD5
Bioconcentration: Also Bioaccumulation. The accumulation of a chemical in tissues of an organism to levels greater than in the environment in which the organism lives.
Biodegradable: Capable of decomposing rapidly under natural conditions.
Biodegradable Plastics: Are plastics that will decompose in the natural environment.
Biodiesel: Is a biofuel produced from various feedstocks including vegetable oils (such as oilseed, rapeseed, and soy beans), animal fat or algae. It can be blended with diesel for use in diesel engine vehicles.
Biodiesel Blend: Blends of biodiesel and diesel fuels. The blend can be with Diesel #1, Diesel #2, or JP8. One standard blend that meets the minimum requirements of the federal EPA Clean Air Act criteria is B20. The number after "B" indicates the percentage of biodiesel included in the blend. In B20, there would be 20%.
Bioenergy: Energy derived from any biological material that can be used as fuel; this fuel is burned or converted in systems that produce heat, electricity, or both heat and power.
Bioethanol: Also known as ethanol, is an alcohol biofuel with the chemical formula CH3CH20H that is traditionally produced by the yeast fermentation and distilation of starch or sugar crops such as corn, sugar beet or sugar cane. Ethanol can also be produced from other feedstocks such as agricultural residues and biomass crops such as switchgrass. This is known as second generation or cellulosic ethanol. Ethanol can be blended with petroleum for use in vehicles. Grain alcohol.
Biofuel: A term that applies to any solid, liquid, or gaseous fuel produced from organic (once-living) matter. The word biofuel covers a wide range of products, some of which are commercially available today and some of which are still in research and development.
Biogas: A combustible gas derived from decomposing biological waste. Biogas normally consists of 50 to 60% methane.
Bioheat: A name sometimes applied to biodiesel when its application is for heating purposes.
Biological Assessment: A specific process required as part of an environmental assessment. An evaluation of potential effects of a proposed project on endangered, threatened and sensitive animal and plant species and their habitats.
Biological Oxidation: Decomposition of organic materials by microorganisms.
Biomass: Is biological material including human, animal, agricultural and forestry waste materials that can be converted into biofuel or bioenergy.
Biomass Fuel: Liquid, solid or gaseous fuel produced by conversion of biomass.
Biomass Processing Residues: Byproducts from processing all forms of biomass that have significant energy potential. For example, making solid wood products and pulp from logs produces bark, shavings and sawdust, and spent pulping liquors. Because these residues are already collected at the point if processing, they can be convenient and relatively inexpensive sources of biomass for energy.
Biopolymers: Are produced from biomass for use in the packaging industry. Biomass crops used to produce biopolymers are classified as non-food stocks. Also known as renewable polymers.
Bioreactor: Is a vessel in which a chemical process occurs. This usually involves organisms or biochemically active substances derived from such organisms.
Biosphere: The portion of the Earth and its atmosphere that can support life.
Biotechnology: Technology that use living organisms to produce products such as medicines, to improve plants or animals, or to produce microorganisms for bioremediation.
Biotic: Pertaining to life or living organisms.
BOD: Biochemical Oxygen Demand. A standard means of estimating the degree of water pollution, especially of water bodies that receive contamination from sewage and industrial waste. BOD is the mount of oxygen needed by bacteria and other microorganisms to decompose organic matter in water. The greater the BOD, the greater the degree of pollution. Biochemical oxygen demand is a process that occurs over a period of time and is commonly measured for a five-day period, referred to as BOD5.
BOD5: The amount of dissolved oxygen consumed in five days by biological processes breaking down organic matter.
See also: Biochemical Oxygen Demand
Boiler: Any device used to burn biomass fuel to heat water for generating steam.
Boiler Horsepower: A measure of the maximum rate of energy output of a steam generator. One boiler horsepower equals 33,480 Btu/hr output in steam
Brewing: Generically, the entire beer-making process, but technically only the pat of the process during which the beer wort is cooked in a brew kettle and during which time the hops are added. After brewing, the beer is fermented.
British Thermal Unit: BTU. A quantitative measure of heat equivalent to the amount of heat required to raise 1 pound of water by 1 degree Fahrenheit.
Brown Grease: Waste grease that is the least expensive of the various grades of wast grease.
BTL: Is a multi-step process which converts biomass into liqiud biofuels. BTL is also referred to as a second generation biodiesel production. There are many diferent methods of BTL, but many processes include Fischer- Tropsch, hydrogenation, or pyrolysis.
BTU: British Thermal Unit. A quantitative measure of heat equivalent to the amount of heat required to raise 1 pound of water by 1 degree Fahrenheit.
Bubble Wash: A method of final washing of biodiesel through air agitation. Biodiesel floats above a quantity of water. Bubbles from an aquarium pump and air stone are injected into the water causing the bubbles to rise. At the water/biodiesel interface, the air bubbles carry water up through the biodiesel by surface tension. Simple diffusion causes water soluble impurities in the biodiesel to be extracted into the water. As the bubble reaches the surface and breaks, the water is freed and percolates back down through the biodiesel again.
Bubble-Cap Trays: Cross flow trays usually installed in rectifying columns handling liquids free of suspended solids. The bubble caps consist of circular cups inverted over small vapor pipes. The vapor from the tray below passes through the vapor pipes into the caps and curves downward to escape below the rim into the liquid. The rim of each cap is slotted or serrated to break up the escaping vapor into small bubbles, thereby increasing the surface area of the vapor as it passes through the liquid.
Bulk Density: Weight per unit of volume, usually specified in pounds per cubic foot.
Bureay of Alcohol, Tobacco, and Firearms: BATF. under the U.S. Department of Treasury. Responsible for the issuance of permits, both experimental and commercial, for the production of alcohol.
Butane: A gas derived from natural gas. used as a component of gasoline. Used in liquefied petroleum gas (LPG) for domestic and industrial applications.
Butanol: An alcohol with the chemical formula CH3(CH2)3OH. It is formed during anaerobic fermentation using bacteria to convert the sugars to butanol and carbon dioxide.
Butyl Alcohol: An alcohol with the chemical formula CH3(CH2)3OH. It is formed during anaerobic fermentation using bacteria to convert the sugars to butanol and carbon dioxide.
Byproduct: A substance, other than the principal product, generated as a consequence of producing a biofuel. For example, a byproduct of ethanol production is DDGS, and a byproduct of biodiesel production is glycerine.
Capacity: The maximum power that a machine or system can produce of carry safely. The maximum instantaneous output of a resource under specified conditions. The capacity of generating equipment is generally expressed in kilowatts or megawatts.
Capacity Factor: The amount of energy that a power plant actually generates compared to its maximum rated output, expressed as a percentage.
Capital Cost: The total investment needed to complete a project and bring it to a commercially operable status. The cost of construction of a new plant. the expenditures tor the purchase or acquisition of existing facilities.
Carbohydrate: A chemical compound made up of carbon, hydrogen, and oxygen. Includes sugars, cellulose, and starches.
Carbon Chain: The atomic structure of hydrocarbons in which a series of carbon atoms, saturated by hydrogen atoms, form a chain. Volatile oils have shorter chains. Fats have longer chain lengths, and waxes have extremely long chains.
Carbon Dioxide: A product of combustion. The most common greenhouse gas.
Carbon Monoxide: CO. A colorless, odorless gas produced by incomplete combustion. Carbon monoxide is poisonous if inhaled.
Carbon Sequestration: The absorption and storage of carbon dioxide from the atmosphere. Naturally-occurring in plants
Carboxyl: The univalent radical, COOH, the functional group characteristic of all organic acids.
Catalyst: A substance that increases the rate of a chemical reaction, without being consumed or produced by the reaction. Enzymes are catalysts for many biochemical reactions.
Cellulase: Enzymes that act to degrade cellulose. Cellulases are produced commonly by fungal and microbial organisms.
Cellulose: The fibrous substance which is contained in leaves, stems, and stalks of plants and trees. It is the most abundant organic compound on earth and can be used to produce ethanol and many other bioproducts.
Cellulosic ethanol: Ethanol fuel produced from cellulose, a naturally occurring complex carbohydrate polymer commonly found in plant cell walls. It is chemically identical to ethanol from other sources, such as corn or sugar, and is available from many biomass resources including urban, agricultural, and forestry residues. Cellulosic ethanol differs from