Day bin: An intermediary solid fuel storage bin that holds enough fuel to last approximately one day. Could be designed with the capacity to feed the combustion system for a weekend.
Deadwood: Dead, standing or fallen, woody biomass from trees or shrubs. Deadwood can be the results of old age, fire, disease, logging, and natural disasters.
Deck: A pile of logs on a landing.
Dehydration: The removal of a substantial portion of the water from any substance.
Dehydrogenation: The removal of hydrogen from a chemical compound.
Delayed coking: A coking process in which the thermal reactions are allowed to proceed to completion to produce gaseous, liquid, and solid (coke) products.
Denaturant: A substance that makes ethanol unfit for consumption.
Density: The mass (or weight) of a unit volume of any substance at a specified temperature (see also “Specific gravity”).
Demand charges: A class of charges typically found in commercial and industrial electric rates. Demand charges reflect the cost placed on the utility of the maximum number and size of all the electricity-consuming devices in use at any one time during a billing period.
Deoxygenation: A chemical reaction involving the removal of molecular oxygen (O2) from a reaction mixture or solvent.
Depolymerization: is the process of converting a polymer into a monomer or a mixture of monomers.
Design/build: A design and contracting process under which the contractor bears ultimate responsibility for the design and function of the equipment or system installed.
Design specifications: For mechanical systems, specifications (and drawings) produced by the owner’s mechanical or design engineer. Design specifications become part of the contract for the installation. The designer bears ultimate responsibility for the design and function of the system.
Desulfurization: The removal of sulfur or sulfur compounds from a feedback.
Dewatering: refers to the removal of all or part of the contained moisture from biomass as a liquid. see Drying.
DHW: Domestic hot water.
Diameter at breast height (DBH): The diameter measured at approximately breast high from the ground.
Diesel engine: Named after the German engineer Rudolph Diesel, this internal-combustion, compression-ignition engine works by heating fuels and causing them to ignite; can use either petroleum or bioderived fuel.
Diesel fuel: A distillate of fuel oil that has been historically derived from petroleum for use in internal combustion engine; also derived from plant and animal sources.
Diesel, Rudolph: German inventor famed for fashioning the diesel engine, which made its debut at the 1900 World’s Fair; initially engine to run on vegetable-derived fuels.
Digester: An airtight vessel or enclosure in which bacteria decomposes biomass in water to produce biogas.
Digestion: the treatment of material with heat, solvents, chemicals, etc., to cause softening or decomposition.
Direct-burn system: A biomass combustion system in which the primary combustion chamber is located under and directly connected to the combustion chamber of the boiler itself.
Dimethyl ether: Also known as methoxymethane, methyl ether, wood ether, and DME, is a colorless, gaseous ether with with an ethereal smell. Dimethyl ether gas is water soluble and has the formula CH3OCH3. Dimethyl ether is used as an aerosol spray propellant. Dimethyl ether is also a clean-burning alternative to liquified petroleum gas, liquified natural gas, diesel and gasoline. It can be made from natural gas, coal, or biomass.
District heating: The use of a single boiler plant to provide hot water or steam for heating a number of buildings in a locality.
Direct-injection engine: A diesel engine in which fuel is injected directly into the cylinder.
Disaccharides: The class of compound sugars that yields two monosaccharide units upon hydrolysis.
Discount rate: A rate used to convert future costs or benefits to their present value.
Distillate: Any petroleum product produced by boiling crude oil and collecting the vapors produced as a condensate in a separate vessel, for example, gasoline (light distillate), gas oil (middle distillate), or fuel oil (heavy distillate).
Distillation: The primary distillation process which uses high temperature to separate crude oil into vapor and fluids which can then be fed into a distillation or fractionating tower.
Distillers Dried Grains (DDG): The dried grain byproduct of the grain fermentation process, which may be used as a high-protein animal feed.
Distillers Wet Grains (DWG): is the product obtained after the removal of ethyl alcohol by distillation from the yeast fermentation of corn.
Distributed generation: The Generation of electricity from many small on-site energy sources. It has also been called also called dispersed generation, embedded generation or decentralized generation.
Downdraft gasifier: A gasifier in which the product gases pass through a combustion zone at the bottom of the gasifier.
Down Woody Debris: Any piece(s) of dead woody material (includes trunks, branches, and roots) on the ground in forest stands or streams. The woody debris can be categorized as course woody debris or fine woody debris based on its large-end diameter.
Drop-in fuel: a substitute for conventional fuel, that is completely interchangeable and compatible with conventional fuel. A drop-in fuel does not require adaptation of the engine, fuel system or the fuel distribution network, and can be used "as is" in currently available engines in pure form and/or blended in any amount with other drop-in neat, drop-in blend, or conventional fuel.
Dry ton: 2000 lb of biomass on a moisture-free basis.
Drying is a similar process as dewatering, except that the moisture is removed as vapor. see Dewatering.
Dutch oven furnace: One of the earliest types of furnaces, having a large, rectangular box lined with firebrick (refractory) on the sides and top; commonly used for burning wood.