Encyclopedia of Renewable Energy. James G. Speight
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divided by the volume of the container, assuming that the container is full and represents the volume occupied by the solid. The bulk density depends on true density, particle size and size distribution, particle shape, surface moisture, and degree of compaction. The parameter is often used in the design of coal handling, transportation, and storage systems.
Bulk density is a property of powders, granules, and other “divided” solids, especially used in reference to coal and similar solids. The total volume includes particle volume, inter-particle void volume, and internal pore volume.
The bulk density is not an intrinsic property of a material; it can change depending on how the material is handled. For example, powdered coal poured into a cylinder will have a particular bulk density, but if the cylinder is disturbed, the coal particles will move and usually settle closer together, resulting in a higher bulk density. For this reason, the bulk density of powders is usually reported both as freely settled and tapped density – the tapped density refers to the bulk density of the coal powder after a specified compaction process, usually involving vibration of the container.
The test method (ASTM D29l) for determining bulk density concerns the compaction of crushed coal to determine either its compacted or uncompacted weight, for purposes such as charging coke ovens. In addition to the character of the coal itself, moisture content and size distribution of the coal are the two main factors that affect the cubic foot weight. A moisture determination and sieve analysis of the coal should be reported along with the cubic foot weight for proper interpretation of the cubic foot weight. During the period of collecting the gross sample, the increments of the sample shall be stored in a waterproof container with a tightly fitting cover in order to prevent the loss of moisture.
The bulk density differs widely between different types of biomass. Together with the heating value, it determines the energy density of the gasifier feedstock, i.e., the potential energy available per unit volume of the feedstock. Biomass of low bulk density is expensive to handle, transport, and store. Apart from handling and storing behavior, the bulk density is important for the performance of the biomass as a fuel inside the reactor: a high void space tends to result in channeling, bridging, incomplete conversion and a decrease in the capacity of the gasifier. The bulk density varies widely (100 to 1,000 kg/m3) between different biomass feedstocks not only because of the character of the biomass but also as a result of the way the biomass comes available (chips, loose, baled).
Bunker
A bunker is a storage tank used for gaseous fuels, liquid fuels, and biomass fuel products.
Fuel bunkers, commonly known as bunkers, are containers for the storage of fuel on steam-powered boats or steam tank engines or rooms for the storage of fuel in furnaces. The term bunker or fuel bunker is typically only used for storage areas for solid fuels (such as coal or, in the current context, solid biofuel). The term fuel tank is typically used for liquid fuels) or gaseous fuels.
Bunker Fuel Oil
Bunker fuel is technically any type of fuel oil used aboard ships. It gets its name from the containers on ships and in ports that it is stored in; in the days of steam, they were coal bunkers, but now, they are bunker-fuel tanks.
Bunker fuel is the colloquial term for fuel oil used by marine vessels. Bunker fuels A, B, and C are respectively downgrading quality-classifications of fuel oil, characterized by their boiling points, carbon-chain lengths, and viscosities, all of which contribute to their value (in other words, Bunker A is more valuable than Bunker C). Currently, most of the global shipping fleet relies on diesel Bunker C fuel oil which contributes significant amounts of greenhouse gas emissions, sulfur, and other emissions that contribute negatively to climate change and negative environmental and human health impacts.
More specifically, bunker A is No. 2 fuel oil, bunker B is No. 4 or No. 5, and bunker C is No. 6. Since No. 6 is the most common, bunker fuel is often used as a synonym for No. 6. No. 5 fuel oil is also called navy special fuel oil or just navy special, No. 6 or 5 are also called furnace fuel oil (FFO); the high viscosity requires heating, usually by a recirculated low pressure steam system, before the oil can be pumped from a bunker tank. In the context of shipping, the labeling of bunkers as previously described is rarely used in modern practice.
Butane
Butane is a gaseous component of natural gas. Butane can also be produced from crude oil. Butane gas (n-butane) is the four-carbon unbranched alkane (CH3CH2CH2CH3). Butane is also used as a collective term for n-butane together with its only other isomer, iso-butane [methylpropane, CH(CH3)3]. Butanes are highly flammable, colorless, odorless, easily liquefied gases.
Butane is sold bottled as a fuel for cooking and camping. When blended with propane and limited amounts of other hydrocarbon derivatives (subject to the specifications), it is referred to commercially as liquefied petroleum gas. It is also used as a gasoline component and as a feedstock for the production of base petrochemicals in steam cracking, as well as a propellant in aerosol sprays.
Very pure forms of butane, especially iso-butane, can be used as refrigerants and have largely replaced the ozone layer-depleting halomethanes in household refrigerators and freezers. The flammability of butane is not usually an issue because the amount of butane in an appliance is not enough to cause a combustible mix given the amount of air in a room.
Butane Dehydrogenation
The butane dehydrogenation process is a process for removing hydrogen from butane to produce butenes and, on occasion, butadiene.
This process is achieved in several ways – the most common method is to heat hydrocarbon derivatives to high temperature, as in thermal cracking, that causes some dehydrogenation. In the chemical process industries, nickel, cobalt, platinum, palladium, and mixtures containing potassium, chromium, copper, aluminum, and other metals are used in very large-scale dehydrogenation processes.
n-Butane, iso-butane, and t-butane, while naturally occurring, have few commercial applications beyond fuels. Butanes can be isomerized and then reacted with iso-butene or other light olefins in alkylation processes to yield high-octane motor gasoline blending stock. Butenes, 1-butene, cis-2-butene, trans-2-butene, and iso-butene, also known as butylenes, by comparison have a variety of commercial uses. Iso-butene is a primary reactant in the production of methyl tertiary butyl ether (MTBE), a major additive in reformulated gasoline and used to reduce emissions from automobile exhaust. Butenes are oligomerized and hydrogenated to produce higher alkanes for gasoline blend stock uses and can be reacted further to produce other commercially important products. It is estimated that 90% of butene consumption is in motor fuel applications such as alkylate, polymer gasoline, and oligomerized gasoline blend stocks. Butenes are also blended directly into gasoline and mixed with propane and butanes in liquefied petroleum gas. Approximately 10% of the available butenes are used in chemical production where the most important products are butadiene, sec-butyl alcohol, butyl rubber, and polybutylene elastomer.
Butenes are produced as by-products of many refinery processes. Due to the huge volumes of crude oil subjected to catalytic cracking, catalytic crackers are the single largest source of mixed butenes that are typically used for MTBE production. Cracking catalysts and conditions are sometimes formulated and selected to especially maximize the production of iso-butene. Steam cracking of olefins is another major source of by-product butenes.
Butenes are dehydrogenated further to produce butadiene. Butadiene is one of three copolymers in abs, acrylonitrile-butadiene-styrene plastic and styrene-butadiene rubber. Dehydrogenation reactions are endothermic, and those of butane and butene are no exception.
One goal of the various processes for producing either