Hydrocarbon fuels steam reforming

There are three primary techniques used to produce hydrogen or syngas from hydrocarbon fuels steam reforming (6.1), partial oxidation (6.2), autofliermal reforming (ATR) (6.3) [1-3]. 

In order to avoid carbon deposition, steam usually needs to be intentionally co-fed with the hydrocarbon vapor introduced into the reactor. Following initial fuel steam reforming, hydrogen, and to a lesser extent CO, are adsorbed on the high surface area fuel-side catalyst and react with oxygen anions to form H2O and CO2. The exothermic oxidation reactions produce heat which drives endothermic steam reforming reactions in a packed bed of catalyst adjacent to the membrane. Steam formed over the oxidation catalysts diffuses to the packed bed of steam reforming catalysts and reacts with hydrocarbon fuel by the reaction ... 

Reformer. This unit chemically converts hydrocarbon or alcohol to synthesis gas (a mixture of hydrogen and carbon monoxide). The two most practical oxidants are steam and air. If air is used, the reformer is referred to as a partial oxidation (POX) reformer if steam is used, a steam reformer (SR), and if a mix of air and steam is used, an autothermal reformer (ATR). The choice of reformer type depends on a number of factors. Typically, POX reformers are smaller, cheaper, respond faster, and are suitable for a wide range of fuels. Steam reformers enable a higher system efficiency. ATRs and catalytic POX reformers (CPOX) share some of the advantages of each type ... 

The GO produced can naturally also act as a fuel according to reaction (12.45). The steam in reaction (12.48) can further reform the hydrocarbon via steam reforming and assist in providing more easily oxidized products ... 

Phosphoric acid (H3PO3) has thermal, electrochemical stability and low volatility. Hydrogen fuel is also produced from a hydrocarbon through steam reformation i.e.,... 

Phosphoric Acid Fuel Cell. Concentrated phosphoric acid is used for the electrolyte ia PAFC, which operates at 150 to 220°C. At lower temperatures, phosphoric acid is a poor ionic conductor (see Phosphoric acid and the phosphates), and CO poisoning of the Pt electrocatalyst ia the anode becomes more severe when steam-reformed hydrocarbons (qv) are used as the hydrogen-rich fuel. The relative stabiUty of concentrated phosphoric acid is high compared to other common inorganic acids consequentiy, the PAFC is capable of operating at elevated temperatures. In addition, the use of concentrated (- 100%) acid minimizes the water-vapor pressure so water management ia the cell is not difficult. The porous matrix used to retain the acid is usually sihcon carbide SiC, and the electrocatalyst ia both the anode and cathode is mainly Pt. 

Conventional Transportation Fuels. Synthesis gas produced from coal gasification or from natural gas by partial oxidation or steam reforming can be converted into a variety of transportation fuels, such as gasoline, aviation turbine fuel (see Aviation and other gas turbine fuels), and diesel fuel. A widely known process used for this appHcation is the Eischer-Tropsch process which converts synthesis gas into largely aHphatic hydrocarbons over an iron or cobalt catalyst. The process was operated successfully in Germany during World War II and is being used commercially at the Sasol plants in South Africa. 

In the phosphoric acid fuel cell as currently practiced, a premium (hydrogen rich) hydrocarbon (e.g. methane) fuel is steam reformed to produce a hydrogen feedstock to the cell stack for direct (electrochemical) conversion to electrical energy. At the fuel electrode, hydrogen ionization is accomplished by use of a catalytic material (e.g. Pt, Pd, or Ru) to form solvated protons. 

Fuel reforming is popular way for hydrogen production for fuel cell use. Hydrocarbons are used for the fuel resource. Methane (CH4) steam reforming process consists of the following two gas phase reactions with various catalysts. 

Recatro A process for making gas from liquid fuels and other gaseous hydrocarbons by catalytic conversion into rich gas, followed by catalytic steam reforming. Developed by BASF and Lurgi. 

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