Hydrogen from steam reforming hydrocarbons

Traditionally PSA processes have found particularly widespread application in hydrogen production systems wherein the PSA unit is used to produce ultra-high purity hydrogen (99.999%+) from steam-reformed hydrocarbons and other hydrogen sources. However, several limitations have existed with these processes. 

Thousands standard cubic feet (SCF) per day merchant hydrogen from steam reforming of light hydrocarbons or recovered as by-product from chloralkali plants or chemical synthesis operations. 

The selective oxidation or preferential oxidation of CO in hydrogen-rich stream is another important object for ceria based catalysts. The gas mixture from steam reforming/partial oxidation of alcohols or hydrocarbons, followed by the WGS reaction contains mainly FI2, CO2 and a small portion of CO, H2O, and N2. When such gaseous stream would be taken as input for hydrogen fuel cells, the CO has to be removed to avoid poisoning of the anode electrocatalysts. Ceria based nanomaterials, such as ceria/gold, ceria/copper oxide catalysts exhibit suitable catalytic activities and selectivities for CO PROX process. 

Murata, K., Wang, L., Saito, M., Inaba, M., Takahara, I., and Minura, N. Hydrogen production from steam reforming of hydrocarbon oven alkaline-earth metal modified Fe- or Ni-based catalysts. Energy Fuels, 2004, 18, 122. 

Hydrogen production from steam reforming of hydrocarbons over alkaline-earth metal-modified Fe- or Ni-based catalysts. Energy Fuels, 18, 122—126. 

Synthesis Gas Chemicals. Hydrocarbons are used to generate synthesis gas, a mixture of carbon monoxide and hydrogen, for conversion to other chemicals. The primary chemical made from synthesis gas is methanol, though acetic acid and acetic anhydride are also made by this route. Carbon monoxide (qv) is produced by partial oxidation of hydrocarbons or by the catalytic steam reforming of natural gas. About 96% of synthesis gas is made by steam reforming, followed by the water gas shift reaction to give the desired H2 /CO ratio. 

Steam reforming is the reaction of steam with hydrocarbons to make town gas or hydrogen. The first stage is at 700 to 830°C (1,292 to 1,532°F) and 15-40 atm (221 to 588 psih A representative catalyst composition contains 13 percent Ni supported on Ot-alumina with 0.3 percent potassium oxide to minimize carbon formation. The catalyst is poisoned by sulfur. A subsequent shift reaction converts CO to CO9 and more H2, at 190 to 260°C (374 to 500°F) with copper metal on a support of zinc oxide which protects the catalyst from poisoning by traces of sulfur. 

Steam reforming of CH4 CH4 + H2O = CO + 3H2 NH3 synthesis from the elements Hydrogenation of CO and CO2 to form hydrocarbons (Fischer-Tropsch syndresis)... 

RKN A process for making hydrogen from hydrocarbon gases (from natural gas to naphtha) by steam reforming. Developed by Haldor Topsoe in the 1960s as of 1975, 24 plants were operating. 

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