which the bags are collapsed in order to mechanically shear the dust cake from the bag surface.
In mechanical-shaker baghouses, tubular filter bags are fastened onto a cell plate at the bottom of the baghouse and suspended from horizontal beams at the top. The contaminate gas streams enters the bottom of the baghouse and passes through the filter, and the dust collects on the inside surface of the bags. Cleaning a mechanical-shaker baghouse is accomplished by shaking the top horizontal bar from which the bags are suspended. Vibration produced by a motor-driven shaft and cam creates waves in the bags to shake off the dust cake.
In reverse-air baghouses, the bags are fastened onto a cell plate at the bottom of the baghouse and suspended from an adjustable hanger frame at the top. Dirty gas flow normally enters the baghouse and passes through the bag from the inside, and the dust collects on the inside of the bags. In reverse-jet baghouses, individual bags are supported by a metal cage, which is fastened onto a cell plate at the top of the baghouse. Dirty gas enters from the bottom of the baghouse and flows from outside to inside the bags. The metal cage prevents collapse of the bag. Bags are cleaned by a short burst of compressed air injected through a common manifold over a row of bags. The compressed air is accelerated by a venturi nozzle mounted at the reverse-jet baghouse top of the bag. Since the duration of the compressed-air burst is short (0.1 seconds), it acts as a rapidly moving air bubble, traveling through the entire length of the bag and causing the bag surfaces to flex. This flexing of the bags breaks the dust cake, and the dislodged dust falls into a storage hopper below.
Cartridge collectors are another commonly used type of dust collector. Unlike baghouse collectors, in which the filtering media is woven or felt bags, this type of collector employs perforated metal cartridges that contain a pleated, nonwoven filtering media. Due to its pleated design, the total filtering surface area is greater than in a conventional bag of the same diameter, resulting in reduced air-to-media ratio, pressure drop, and overall collector size.
See also: Baghouse Filter.
Baghouse Filter
Baghouse fabric filters are generally used where higher removal efficiency is required for particles smaller than approximately 10 microns. Thus, the filter is an air pollution control device and dust collector that removes particulates or gas released from commercial processes. A large number of bag-shaped filters would be needed to clean large gas flows. In general, all of the filters would be enclosed in the same structure (a baghouse) and would share input and output gas manifolds.
As a gas stream passes through the baghouse, dust is removed by one or more of the following physical phenomena: intersection, impingement, diffusion, gravitational settling, or electrostatic attraction. The initial filtration creates a layer of dust on the bag fabric. This layer is primarily responsible for this method’s high removal efficiency; the filter cloth serves mainly as a support structure.
The efficiency of a baghouse filter depends on the particle size distribution, the particle density and chemistry, and moisture. Under most conditions, a well-designed and well-operated baghouse will achieve a removal efficiency of at least 99% for particles as small as 1 micron. In the renewable energy industry, baghouse filters are likely to be used for dust removal from crushers, screens, transfer points, and storage bins.
Fabric life may be substantially shortened in the presence of high acid or alkaline atmospheres, especially at elevated temperatures; also, the maximum operating temperature is limited to 285°C (550°F), unless special fabrics are used.
See also: Baghouse, Centrifugal Separation, Cyclone Separation.
Barrel
The standard oil barrel of 42 US gallons is used in the United States as a measure of crude oil and other crude oil products. The 42 US gallon size of barrel as a unit of measure is largely confined to the American oil industry, since other sizes of barrel were used by other industries in the United States, and nearly all other countries use the metric system. Many oil-producing countries that did not have the technical expertise to develop their own domestic oil industry standards use the American oil barrel because their oil industries were founded by US oil companies.
Outside of the United States, oil is commonly measured in cubic meters (m3) or in tonnes (1 tonne = 2,204.6 lbs), with tonnes more often being used by European oil companies. International companies listed on American stock exchanges tend to convert their oil production volumes to barrels for global reporting purposes, and those listed on European exchanges tend to convert their production to tonnes.
The wooden oil barrel of the late 1800s is different from the modern day 55-gal steel drum (known as the 44-gal drum in Britain and the 200-L drum in Australia). The 42-US gallon oil barrel is a unit of measure, and is no longer used to transport crude oil – most crude oil is moved in pipelines or oil tankers.
The barrel of oil equivalent (BOE) is a unit of energy based on the approximate energy released by burning one barrel (42 US gallons) of crude oil. The Internal Revenue Service of the United States defines the barrel of oil equivalent as equal to 5.8 × 106 Btu. A barrel of oil equivalent is approximately 6,000 ft3 of typical natural gas.
Other conversion data are the BBOe, (also BBOE), or billion barrel of oil equivalent, representing 109 (US billion) barrels of oil, used to measure crude oil reserves, and million barrels per day, MMbd (or MMBD), used to measure daily production and consumption. Also used is the Mtoe (not middle toe but millions of tonnes of oil equivalent), a metric measurement equivalent to approximately 0.006841 billion barrels of oil equivalent.
The barrel of oil equivalent is used by oil and gas companies in their annual financial statements as a way of combining oil reserves and natural gas reserves as well as production into a single measure.
See also: Barrel of Oil Equivalent.
Barrel of Oil Equivalent
A barrel of oil equivalent (BOE or a barrel of crude oil equivalent, BCOE) is a used to summarize the amount of energy that is equivalent to the amount of energy found in a barrel of crude oil. Thus, a barrel of crude oil is a liquid measure equal to 42 US gallons (35 Imperial gallons or 158.9873 L). The BOE is the amount of energy contained in a barrel of crude oil; a barrel of crude oil is approximately (because of the difference in crude oil properties and character) equivalent to 5.8 million Btu. Also, approximately 7.2 barrels of oil are equivalent to one ton of oil. A BOE is approximately roughly 6,000 ft3 of natural gas.
A commonly used multiple of the BOE is the kilo-barrel of oil equivalent (kboe or kBOE), which is 1,000 times larger. Other common multiples are the billion BOE, representing 109 barrels of oil, used to measure crude oil reserves, and million barrels per day (MMbd or MMBD), used to measure daily production and consumption. Also used is the million tons of oil equivalent (Mtoe) which is a metric measurement equivalent to approximately 0.006841 billion barrels of crude oil equivalent.
The BOE is used by oil and gas companies in their financial statements as a way of combining crude oil reserves and natural gas reserves and production into a single measure.
See also: Barrel, Resources And Reserves.
Basic Nitrogen
Nitrogen in liquid fuels (renewable fuels are included here) may be classified arbitrarily as basic and non-basic (Table
