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High-pressure Electrolysis
High-pressure electrolysis (HPE) is the electrolysis of water by decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) due to the passing of an electric current through the water. The difference with a standard proton exchange membrane electrolyzer is the compressed hydrogen output around at 70 °C. By pressurising the hydrogen in the electrolyser the need for an external hydrogen compressor is eliminated, the average energy consumption for internal differential pressure compression is around 3%. Approaches As the required compression power for water is less than that for hydrogen-gas the water is pumped up to a high-pressure, in the other approach differential pressure is used. There is also an importance for the electrolyser stacks to be able to accept a fluctuating electrical input, such as that found with renewable energy. This then enables the ability to help with grid balancing and energy storage. Ultrahigh-pressure electrolysis Ultrahigh-pressure el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-pressure PEM Electrolyser Stacks
In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. By ''high pressure'' is usually meant pressures of thousands (kilobars) or millions (megabars) of times atmospheric pressure (about 1 bar or 100,000 Pa). History and overview Percy Williams Bridgman received a Nobel Prize in 1946 for advancing this area of physics by several magnitudes of pressure (400 MPa to 40,000 MPa). The list of founding fathers of this field includes also the names of Harry George Drickamer, Tracy Hall, Francis P. Bundy, Leonid F. Vereschagin, and Sergey M. Stishov. It was by applying high pressure as well as high temperature to carbon that man-made diamonds were first produced as well as many other interesting discoveries. Almost any material when subjected to high pressure will compact itself into a denser form, for example, quartz, also called silica or silicon di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Purity
Hydrogen purity or hydrogen quality describes the presence of impurities in hydrogen when used as a fuel gas. Impurities in hydrogen can interfere with the proper functioning of equipment that stores, distributes, or uses hydrogen fuel. Hydrogen Purity Requirements The impact of impurities varies with the specific equipment used and on the physio-chemical nature of the impurity. For example, hydrogen boilers that combust hydrogen will generally tolerate higher concentrations of impurities than a vehicle using a polymer electrolyte membrane fuel cell (PEMFC) and inert impurities such as nitrogen are usually less harmful than reactive species such as hydrogen sulphide. As the specific impurity matters it is not sufficient to rely on normal metrics of gas purity, often reported using nines (e.g. >99.9990% or 5.0N), as this does not provide adequate information about which impurities may be present at trace levels. Instead, standards have been developed that provide more detailed r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. There are a wide number of different types of fuel and electrolysis cells. The potential envir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-temperature Electrolysis
High-temperature electrolysis (also HTE or steam electrolysis) is a technology for producing hydrogen from water at high temperatures. Efficiency High temperature electrolysis is more efficient economically than traditional room-temperature electrolysis because some of the energy is supplied as heat, which is cheaper than electricity, and also because the electrolysis reaction is more efficient at higher temperatures. In fact, at 2500 °C, electrical input is unnecessary because water breaks down to hydrogen and oxygen through thermolysis. Such temperatures are impractical; proposed HTE systems operate between 100 °C and 850 °C. If one assumes that the electricity used comes from a heat engine, it takes 141.86 megajoules (MJ) of heat energy to produce one kg of hydrogen, for the HTE process itself and for the electricity required. At 100 °C, 350 MJ of thermal energy are required (41% efficient). At 850 °C, 225 MJ are required (64% efficient). Above 8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemical Engineering
Electrochemical engineering is the branch of chemical engineering dealing with the technological applications of electrochemical phenomena, such as electrosynthesis of chemicals, electrowinning and refining of metals, flow batteries and fuel cells, surface modification by electrodeposition, electrochemical separations and corrosion. This discipline is an overlap between electrochemistry and chemical engineering. According with the IUPAC, the term ''electrochemical engineering'' is reserved for electricity intensive processes for industrial or energy storage applications, and should not be confused with ''applied electrochemistry'', which comprises small batteries, amperometric sensors, microfluidic devices, microelectrodes, solid-state devices, voltammetry at disc electrodes, etc. More than 6% of the electricity is consumed by large-scale electrochemical operations in the US. Scope Electrochemical engineering combines the study of heterogeneous charge transfer at electrode/ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regenerative Fuel Cell
A regenerative fuel cell or reverse fuel cell (RFC) is a fuel cell run in reverse mode, which consumes electricity and chemical B to produce chemical A. By definition, the process of any fuel cell could be reversed. However, a given device is usually optimized for operating in one mode and may not be built in such a way that it can be operated backwards. Standard fuel cells operated backwards generally do not make very efficient systems unless they are purpose-built to do so as with high-pressure electrolysers, regenerative fuel cells, solid-oxide electrolyser cells and unitized regenerative fuel cells. Process description A hydrogen fueled proton exchange membrane fuel cell, for example, uses hydrogen gas (H2) and oxygen (O2) to produce electricity and water (H2O); a regenerative hydrogen fuel cell uses electricity and water to produce hydrogen and oxygen. When the fuel cell is operated in regenerative mode, the anode for the electricity production mode (fuel cell mode) becomes th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PEM Electrolysis
Polymer electrolyte membrane (PEM) electrolysis is the electrolysis of water in a cell equipped with a solid polymer electrolyte (SPE) that is responsible for the conduction of protons, separation of product gases, and electrical insulation of the electrodes. The PEM electrolyzer was introduced to overcome the issues of partial load, low current density, and low pressure operation currently plaguing the alkaline electrolyzer. It involves a proton-exchange membrane. Electrolysis of water is an important technology for the production of hydrogen to be used as an energy carrier. With fast dynamic response times, large operational ranges, and high efficiencies, water electrolysis is a promising technology for energy storage coupled with renewable energy sources. In terms of sustainability and environmental impact, PEM electrolysis is considered as a promising technique for high purity and efficient hydrogen production since it emits only oxygen as a by-product without any carbon emissi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-pressure Hydrogen Energy Generator
In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. By ''high pressure'' is usually meant pressures of thousands (kilobars) or millions (megabars) of times atmospheric pressure (about 1 bar or 100,000 Pa). History and overview Percy Williams Bridgman received a Nobel Prize in 1946 for advancing this area of physics by several magnitudes of pressure (400 MPa to 40,000 MPa). The list of founding fathers of this field includes also the names of Harry George Drickamer, Tracy Hall, Francis P. Bundy, Leonid F. Vereschagin, and Sergey M. Stishov. It was by applying high pressure as well as high temperature to carbon that man-made diamonds were first produced as well as many other interesting discoveries. Almost any material when subjected to high pressure will compact itself into a denser form, for example, quartz, also called silica or silicon di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gasoline Gallon Equivalent
Gasoline gallon equivalent (GGE) or gasoline-equivalent gallon (GEG) is the amount of an alternative fuel it takes to equal the energy content of one liquid gallon of gasoline. GGE allows consumers to compare the energy content of competing fuels against a commonly known fuel, namely gasoline. It is difficult to compare the cost of gasoline with other fuels if they are sold in different units and physical forms. GGE attempts to solve this. One GGE of CNG and one GGE of electricity have exactly the same energy content as one gallon of gasoline. In this way, GGE provides a direct comparison of gasoline with alternative fuels, including those sold as a gas (natural gas, propane, hydrogen) and as metered electricity. Definition In 1994, the US National Institute of Standards and Technology (NIST) defined "gasoline gallon equivalent (GGE) s5.660 pounds of natural gas." Compressed natural gas (CNG), for example, is a gas rather than a liquid. It can be measured by its volume in stan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Energy
The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United States. The DOE oversees the U.S. nuclear weapons program, nuclear reactor production for the United States Navy, energy-related research, and domestic energy production and energy conservation. The DOE was created in 1977 in the aftermath of the 1973 oil crisis. It sponsors more physical science research than any other U.S. federal agency, the majority of which is conducted through its system of National Laboratories. The DOE also directs research in genomics, with the Human Genome Project originating from a DOE initiative. The department is headed by the Secretary of Energy, who reports directly to the president of the United States and is a member of the Cabinet. The current Secretary of Energy is Jennifer Granholm, who has served ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Safety
Hydrogen safety covers the safe production, handling and use of hydrogen, particularly hydrogen gas fuel and liquid hydrogen. Hydrogen possesses the NFPA 704's highest rating of 4 on the flammability scale because it is flammable when mixed even in small amounts with ordinary air; ignition can occur at a volumetric ratio of hydrogen to air as low as 4% due to the oxygen in the air and the simplicity and chemical properties of the reaction. However, hydrogen has no rating for innate hazard for reactivity or toxicity. The storage and use of hydrogen poses unique challenges due to its ease of leaking as a gaseous fuel, low-energy ignition, wide range of combustible fuel-air mixtures, buoyancy, and its ability to embrittle metals that must be accounted for to ensure safe operation. Liquid hydrogen poses additional challenges due to its increased density and the extremely low temperatures needed to keep it in liquid form. Moreover, its demand and use in industry—as rocket fuel, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Storage
Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in multiple forms including radiation, chemical, gravitational potential, electrical potential, electricity, elevated temperature, latent heat and kinetic. Energy storage involves converting energy from forms that are difficult to store to more conveniently or economically storable forms. Some technologies provide short-term energy storage, while others can endure for much longer. Bulk energy storage is currently dominated by hydroelectric dams, both conventional as well as pumped. Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Common examples of energy storage are the rechargeable battery, which stores chemical energy readily convertible to electricity to operate a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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