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Hydrogen Technologies
Hydrogen technologies are technologies that relate to the production and use of hydrogen as a part hydrogen economy. Hydrogen technologies are applicable for many uses. Some hydrogen technologies are carbon neutral and could have a role in preventing climate change and a possible future hydrogen economy. Hydrogen is a chemical widely used in various applications including ammonia production, oil refining and energy. The most common methods for producing hydrogen on an industrial scale are: Steam reforming, oil reforming, coal gasification, water electrolysis. Hydrogen is not a primary energy source, because it is not naturally occurring as a fuel. It is, however, widely regarded as an ideal energy storage medium, due to the ease with which electricity can convert water into hydrogen and oxygen through electrolysis and can be converted back to electrical power using a fuel cell or hydrogen turbine. There are a wide number of different types of fuel and electrolysis ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technology
Technology is the application of Conceptual model, conceptual knowledge to achieve practical goals, especially in a reproducible way. The word ''technology'' can also mean the products resulting from such efforts, including both tangible tools such as Kitchen utensil, utensils or machines, and intangible ones such as software. Technology plays a critical role in science, engineering, and everyday life. Technological advancements have led to significant changes in society. The earliest known technology is the stone tool, used during prehistory, followed by the control of fire—which in turn contributed to the Brain size, growth of the human brain and the development of language during the Pleistocene, Ice Age, according to the cooking hypothesis. The invention of the wheel in the Bronze Age allowed greater travel and the creation of more complex machines. More recent technological inventions, including the printing press, telephone, and the Internet, have lowered barriers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of either a positive or negative electric charge produces an electric field. The motion of electric charges is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the Work (physics), work done to move an electric charge from one point to another within an electric field, typically measured in volts. Electricity plays a central role in many modern technologies, serving in electric power where electric current is used to energise equipment, and in electronics dealing w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbial Fuel Cell
Microbial fuel cell (MFC) is a type of bioelectrochemical fuel cell system also known as micro fuel cell that generates electric current by diverting electrons produced from the microbial oxidation of reduced compounds (also known as fuel or electron donor) on the anode to oxidized compounds such as oxygen (also known as oxidizing agent or electron acceptor) on the cathode through an external electrical circuit. MFCs produce electricity by using the electrons derived from biochemical reactions catalyzed by bacteria.MFCs can be grouped into two general categories: mediated and unmediated. The first MFCs, demonstrated in the early 20th century, used a mediator: a chemical that transfers electrons from the bacteria in the cell to the anode. Unmediated MFCs emerged in the 1970s; in this type of MFC the bacteria typically have electrochemically active redox proteins such as cytochromes on their outer membrane that can transfer electrons directly to the anode. In the 21st century MFC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Hydride Fuel Cell
Metal hydride fuel cells are a subclass of alkaline fuel cells that have been under research and development, as well as scaled up successfully in operating systems. A notable feature is their ability to chemically bond and store hydrogen within the fuel cell itself. Characteristics Metal hydride fuel cells have demonstrated the following characteristics: * The ability to be recharged with electrical energy (similar to NiMH batteries) * Operating at low temperatures (down to −20 °C) * Fast "cold start" properties * Ability to operate for limited periods of time with no external hydrogen fuel source, enabling "hot swapping" of fuel canisters Performance Electrode active areas of metal hydride fuel cells have been scaled up from 60 cm2 to 250 cm2, enabling systems to be scaled up to 500 Watts. The scaling up of electrode active areas also provided capabilities to develop higher power fuel cell stacks, each with 1500 Watts of power. Metal hydride fuel cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formic Acid Fuel Cell
Formic acid fuel cells (direct formic acid fuel cells or DFAFCs) are a subcategory of direct liquid-feed fuel cells (DLFCs), in which the liquid fuel is directly oxidized (electrochemically) at the anode instead of reforming to produce hydrogen. Formic acid-based fuel cells represent a promising energy supply system in terms of high volumetric energy density, theoretical energy efficiency, and theoretical open-circuit voltage. They are also able to overcome certain problems inherent to traditional hydrogen (H2) feed fuel cells such as safe handling, storage, and H2 transportation. There are 3 main types of DFAFCs: * Active DFAFCs, where a pump feeds the liquid fuel into the anode and oxygen in compressed air to the cathode. * Active air-breathing DFAFCs, where the cathode is exposed to the oxygen present in ambient air. * Passive air-breathing DFAFCs, where there are no mechanical components injecting fuels and oxygen into the cell. The feeding of fuels and air into a cell increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Methanol Fuel Cell
Direct methanol fuel cells or DMFCs are a subcategory of proton-exchange membrane fuel cells in which methanol is used as the fuel and a special proton-conducting polymer as the membrane (PEM). Their main advantage is low temperature operation and the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions. Whilst the thermodynamic theoretical energy conversion efficiency of a DMFC is 97%; as of 2014 the achievable energy conversion efficiency for operational cells attains 30% – 40%. There is intensive research on promising approaches to increase the operational efficiency. A more efficient version of a direct fuel cell would play a key role in the theoretical use of methanol as a general energy transport medium, in the hypothesized methanol economy. The cell In contrast to indirect methanol fuel cells, where methanol is reacted to hydrogen by steam reforming, DMFCs use a methanol solution (usually around 1 M, i.e. about 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Ethanol Fuel Cell
Direct-ethanol fuel cells or DEFCs are a category of fuel cell in which ethanol is fed directly into the cell. They have been used as a model to investigate a range of fuel cell concepts including the use of PEM. Advantages DEFC uses Ethanol in the fuel cell instead of the more toxic methanol. Ethanol is an attractive alternative to methanol because it comes with a supply chain that's already in place. Ethanol also remains the easier fuel to work with for widespread use by consumers. Ethanol is a hydrogen-rich liquid and it has a high energy density (8.0 kWh/kg) compared to methanol (6.1 kWh/kg). Ethanol can be obtained in great quantity from biomass through a fermentation process from renewable resources like from sugar cane, wheat, corn, or even straw. Bio-generated ethanol (or bio-ethanol) is thus attractive since growing crops for biofuels absorbs much of the carbon dioxide emitted into the atmosphere from fuel used to produce the biofuels, and from burning the biofuels th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Carbon Fuel Cell
A Direct Carbon Fuel Cell (DCFC) is a fuel cell that uses a carbon rich material as a fuel such as bio-mass or coal. The cell produces energy by combining carbon and oxygen, which releases carbon dioxide as a by-product. It is also called coal fuel cells (CFCs), carbon-air fuel cells (CAFCs), direct carbon/coal fuel cells (DCFCs), and DC-SOFC. The total reaction of the cell is C + O2 → CO2. The process in half cell notation: * Anode: C + 2O2− → CO2 + 4e− * Cathode: O2 + 4e− → 2O2− Despite this release of carbon dioxide, the direct carbon fuel cell is more environmentally friendly than traditional carbon burning techniques. Due to its higher efficiency, it requires less carbon to produce the same amount of energy. Also, because pure carbon dioxide is emitted, carbon capture techniques are much cheaper than for conventional power stations. Utilized carbon can be in the form of coal, coke, char, or a non-fossilized source of carbon. At least four types of DCFC exist. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Borohydride Fuel Cell
Direct borohydride fuel cells (DBFCs) are a subcategory of alkaline fuel cells which are directly fed by sodium borohydride or potassium borohydride as a fuel and either air/oxygen or hydrogen peroxide as the oxidant. DBFCs are relatively new types of fuel cells which are currently in the developmental stage and are attractive due to their high operating potential in relation to other type of fuel cells. Recently, DBFCs that rival proton-exchange membrane fuel cells (PEMFCs) in peak power but operating at double the voltage have been reported. Chemistry Sodium borohydride has been used with more conventional hydrogen fuel cell systems as a means of storing hydrogen. The hydrogen can be regenerated for a fuel cell by catalytic decomposition of the borohydride with water, including successful hydration with synthetic urine: :NaBH4 + 2H2O → NaBO2 + 4H2 Direct borohydride fuel cells decompose and oxidize the borohydride directly, side-stepping hydrogen production and even produci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaline Fuel Cell
In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases. Etymology The word ''alkali'' is derived from Arabic ''al qalīy'' (or ''alkali''), meaning (see calcination), referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed mostly of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide (''slaked lime''), a far more strongly basic substance known as ''caustic potash' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
