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Solid Oxide Electrolyzer Cell
A solid oxide electrolyzer cell (SOEC) is a solid oxide fuel cell that runs in regenerative mode to achieve the electrolysis of water (and/or carbon dioxide) by using a solid oxide, or ceramic, electrolyte to produce hydrogen gas (and/or carbon monoxide) and oxygen. The production of pure hydrogen is compelling because it is a clean fuel that can be stored, making it a potential alternative to batteries, methane, and other energy sources (see hydrogen economy). Electrolysis is currently the most promising method of hydrogen production from water due to high efficiency of conversion and relatively low required energy input when compared to thermochemical and photocatalytic methods. Principle Solid oxide electrolyzer cells operate at temperatures which allow high-temperature electrolysis to occur, typically between 500 and 850 °C. These operating temperatures are similar to those conditions for a solid oxide fuel cell. The net cell reaction yields hydrogen and oxygen gases. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid Oxide Electrolyser Cell Prefab
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice ( crystalline solids, which include metals and ordinary ice), or irregularly (an amorphous solid such as common window glass). Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed. The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials sci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Splitting
Water splitting is the chemical reaction in which water is broken down into oxygen and hydrogen: :2 H2O → 2 H2 + O2 Efficient and economical water splitting would be a technological breakthrough that could underpin a hydrogen economy, based on green hydrogen. A version of water splitting occurs in photosynthesis, but hydrogen is not produced. The reverse of water splitting is the basis of the hydrogen fuel cell. Electrolysis Electrolysis of water is the decomposition of water (H2O) into oxygen (O2) and hydrogen (H2) due to an electric current being passed through the water. : * Vion, , "Improved method of using atmospheric electricity", June 1860. In power-to-gas production schemes, the excess power or off peak power created by wind generators or solar arrays is used for load balancing of the energy grid by storing and later injecting the hydrogen into the natural gas grid. Production of hydrogen from water is energy intensive. Potential electrical energy supplies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syngas
Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principly used for producing ammonia or methanol. Syngas is combustible and can be used as a fuel. Historically, it has been used as a replacement for gasoline, when gasoline supply has been limited; for example, wood gas was used to power cars in Europe during WWII (in Germany alone half a million cars were built or rebuilt to run on wood gas). Production Syngas is produced by steam reforming or partial oxidation of natural gas or liquid hydrocarbons, or coal gasification. Steam reforming of methane is an endothermic reaction requiring 206 kJ/mol of methane: : In principle, but rarely in practice, biomass and related hydrocarbon feedstocks could be used to generate biogas and biochar in waste-to-energy gasification facilities. The gas generated (mostly methane and carbon dioxide) is sometimes described as ''syngas'' but its co ... [...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] |
Unitized Regenerative Fuel Cell
A unitized regenerative fuel cell (URFC) is a fuel cell based on the proton exchange membrane which can do the electrolysis of water in regenerative mode and function in the other mode as a fuel cell recombining oxygen and hydrogen gas to produce electricity. Both modes are done with the same fuel cell stack 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. Fuel cells operated backwards generally do not make very efficient systems unless they are purpose-built to do so as in high pressure electrolyzers, unitized regenerative fuel cells and regenerative fuel cells. History Livermore physicist Fred Mitlitsky studied the possibilities of reversible technology. In the mid-1990s Mitlitsky received some funding from NASA for development of Helios and from the Department of Energy for leveling peak and intermittent power usage with s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel Cell
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied. The first fuel cells were invented by Sir William Grove in 1838. The first commercial use of fuel cells came more than a century later following the invention of the hydrogen–oxygen fuel cell by Francis Thomas Bacon in 1932. The alkaline fuel cell, also known as the Bacon fuel cell after its inventor, has been used in NASA space programs since the mid-1960s to generate power for satellites and space capsules. Since then, fuel cells have b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. The concept of diffusion is widely used in many fields, including physics (particle diffusion), chemistry, biology, sociology, economics, and finance (diffusion of people, ideas, and price values). The central idea of diffusion, however, is common to all of these: a substance or collection undergoing diffusion spreads out from a point or location at which there is a higher concentration of that substance or collection. A gradient is the change in the value of a quantity, for example, concentration, pressure, or temperature with the change in another variable, usually distance. A change in c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Expansion
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. As energy in particles increases, they start moving faster and faster weakening the intermolecular forces between them, therefore expanding the substance. Overview Predicting expansion If an equation of state is available, it can be used to predict the values of the thermal expan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnot Efficiency
A Carnot cycle is an ideal thermodynamic cycle proposed by French physicist Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. By Carnot's theorem, it provides an upper limit on the efficiency of any classical thermodynamic engine during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference through the application of work to the system. In a Carnot cycle, a system or engine transfers energy in the form of heat between two thermal reservoirs at temperatures T_H and T_C (referred to as the hot and cold reservoirs, respectively), and a part of this transferred energy is converted to the work done by the system. The cycle is reversible, and there is no generation of entropy. (In other words, entropy is conserved; entropy is only transferred between the thermal reservoirs and the system without gain or loss of it.) When work is applied to the system, heat moves from the cold to hot reser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neodymium Nickelate
Neodymium nickelate is a nickelate of neodymium with a chemical formula NdNiO3. In this compound, the neodymium atom is in the +3 oxidation state. Preparation Neodymium nickelate can be prepared by dissolving neodymium(III) oxide and nickel(II) oxide in nitric acid, followed by heating the mixture in an oxygen atmosphere. It can also be prepared by pyrolyzing a mixture of nickel nitrate and neodymium nitrate. It decomposes in high temperature (950 °C) by nitrogen: :4 NdNiO3 → 2 Nd2NiO4 + 2 NiO + O2 It can also be reduced to the monovalent nickel compound NdNiO2 by sodium hydride at 160 °C. Physical properties Neodymium nickelate shows metal-insulator transition (MIT) under low temperature. The temperature at which it transforms (TMIT) is 200K, which is higher than praseodymium nickelate (130K) but lower than samarium nickelate (400K). It transforms from antiferromagnetism to paramagnetism. It has demonstrated to be a first-order phase transition (this applies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yttrium(III) Oxide
Yttrium oxide, also known as yttria, is Y2 O3. It is an air-stable, white solid substance. The thermal conductivity of yttrium oxide is 27 W/(m·K). Uses Phosphors Yttria is widely used to make Eu:YVO4 and Eu:Y2O3 phosphors that give the red color in color TV picture tubes. Yttria lasers Y2O3 is a prospective solid-state laser material. In particular, lasers with ytterbium as dopant allow the efficient operation both in continuous operation and in pulsed regimes. At high concentration of excitations (of order of 1%) and poor cooling, the quenching of emission at laser frequency and avalanche broadband emission takes place. (Yttria-based lasers are not to be confused with YAG lasers using yttrium aluminum garnet, a widely used crystal host for rare earth laser dopants). Gas Lighting The original use of the mineral yttria and the purpose of its extraction from mineral sources was as part of the process of making gas mantles and other products for turning the flames of artific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
