Encyclopedia of Renewable Energy. James G. Speight
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oil.
The Brent crude oil blend is based on the prices of Brent crude, which is a light, sweet crude oil and is actually a combination of crude oil from 15 different oil fields in the Brent and Ninian systems located in the North Sea. The API gravity is 38.3° (making it a “light” crude oil, but not quite as “light” as West Texas Intermediate crude oil), while it contains approximately 0.37% by weight sulfur (making it a sweet crude oil, but again slightly less sweet than West Texas Intermediate crude oil). The Brent blend is ideal for making gasoline and middle distillates, both of which are consumed in large quantities in Northwest Europe, where Brent blend crude oil is typically refined. However, if the arbitrage between Brent and other crude oils, including WTI, is favorable for export, Brent has been known to be refined in the United States (typically the East Coast or the Gulf Coast) or the Mediterranean region. Brent blend, like West Texas Intermediate crude oil, production is also on the decline, but it remains the major benchmark for other crude oils in Europe or Africa.
Beta Decay
Beta decay (β-decay) is a type of radioactive in which a beta particle (a fast energetic electron or positron) is emitted from an atomic nucleus which transforms the original nuclide to an isobar of that nuclide.
By definition, an isobar is an atom (nuclide) of different chemical elements that have the same number of nucleons. Correspondingly, an isobar differs in atomic number (or the number of protons) but has the same mass number. An example of a series of isobars is 40S, 40Cl, 40Ar, 40K, and 40Ca.
Thus, the beta decay of a neutron transforms it into a proton by the emission of an electron accompanied by an antineutrino or, conversely, a proton is converted into a neutron by the emission of a positron with a neutrino in the positron emission reaction. Neither the beta particle nor its associated (anti-)neutrino exist within the nucleus prior to beta decay, but are created in the decay process. By this process, unstable atoms obtain a more stable ratio of protons to neutrons. The probability of a nuclide decaying due to beta and other forms of decay is determined by the nuclear binding energy.
Thus, the two types of beta decay are known as beta minus and beta plus. In the former [beta minus decay (β− decay)], a neutron is converted to a proton, and the process creates an electron and an electron antineutrino, while in beta plus decay (β+ decay, also known as positron emission), a proton is converted to a neutron and the process creates a positron and an electron neutrino.
An example of electron emission (β− decay) is the decay of carbon-14 (14C) into nitrogen-14 (14N) with a half-life on the order of 5,730 years:
In this form of decay, the original element becomes a new chemical element (nuclear transmutation) and the new element has an unchanged mass number (A) but anatomic number (Z) that is increased by one. As in all nuclear decays, the decaying element (in this case 146C) is the parent nuclide, while the resulting element (in this case 147N) is known as the daughter nuclide.
Another example is the decay of hydrogen-3 (3H, tritium) into helium-3 (3He) with a half-life on the order of 12.3 years:
An example of positron emission (β+ decay) is the decay of magnesium-23 (23Mg) into sodium-23 (23Na) with a half-life on the order of 11.3 seconds:
Beta+ decay (β+ decay) also results in nuclear transmutation, with the resulting element having an atomic number that is decreased by one.
See also: Alpha Decay, Alpha Particle, Nuclear Energy.
Beta Particle
A beta particle is emitted from the nucleus of a radioactive atom with a wide range of energies up to some maximum value. When a beta particle is emitted that is below the maximum value, the neutrino carries away the rest of the energy.
Like the alpha particles, beta particles, like alpha particles, lose energy by ionization and excitation, but because of their small mass (1/7,300 of an alpha particle) and lower charge (1/2 of that of an alpha particle), the interactions take place at less frequent intervals. Therefore, the beta particles do not produce as many ion pairs per centimeter of path as alpha particles, and thus, have a greater range in matter which depends on the energy of the particle and the composition of the material.
See also: Alpha Decay, Alpha Particle, Nuclear Energy.
Bioalcohol
Biologically produced alcohols, such as ethanol, propanol and butanol, are produced by the action of microorganisms and enzymes through the fermentation of starches, sugars, or cellulose. Alcohol fuels are produced by fermentation of sugars derived from corn, molasses, sugar beets, sugar cane, wheat, as well as potato and fruit waste.
However, as an example, there is no difference in properties between ethyl alcohol produced in a petrochemical facility and ethanol from biomass; it is merely the use of the prefix “bio” to define the origin of the alcohol. However, in some cases, ethanol (C2H5OH) that is derived from crude oil should not be considered safe for consumption as this alcohol contains approximately 5% v/v methanol (CH3OH) and may cause blindness or death. This mixture may also not be purified by simple distillation, as it forms an azeotropic mixture.
Bioalcohols are a useful type of liquid fuel because they combust rapidly and are often cheap to produce. However, their acceptance is hampered by the fact that their production often requires as much or even more fossil fuel than they replaced since they are typically not primary sources of energy; however, they are a convenient way to store the energy for transportation.
Biomethanol
Methanol (the simplest alcohol, CH3OH) is the lowest molecular weight and simplest alcohol, produced from natural gas (methane). It is also called methyl alcohol or wood alcohol, the latter because it was formerly produced from the distillation of wood. Currently, the majority of the methanol produced is manufactured from natural gas, a nonrenewable fossil fuel, and modern methanol is also produced in a catalytic industrial process directly from carbon monoxide, carbon dioxide, and hydrogen. However, methanol can also be produced from biomass (as biomethanol) using similar chemical processes.
Bioethanol
Ethanol, also known as grain alcohol or ethyl alcohol, is most commonly used in alcoholic beverages. The ethanol production methods used are enzyme digestion (to release sugars from stored starches), fermentation of the sugars, distillation, and drying. Ethanol is produced mostly from carbohydrates produced in starch and sugar crops such as corn or sugar cane. The distillation process requires significant energy input for heat (often unsustainable natural gas, but cellulosic biomass such as bagasse, the waste left after sugar cane is pressed to extract its juice, can also be used more sustainably). Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions.
Two types of grain ethanol production are currently available in the United States, dry milling and wet milling, with the latter predominating among large-scale producers.
Corn dry milling is the most common type of ethanol production in the United States. In the dry grind process, the entire corn kernel is first ground into flour and the starch in the flour is converted to ethanol via fermentation. The other products are carbon dioxide (used in the carbonated beverage industry)