Steam hydrocarbon reforming operating problems

HTS catalyst consists mainly of magnetite crystals stabilized using chromium oxide. Phosphoms, arsenic, and sulfur are poisons to the catalyst. Low reformer steam to carbon ratios give rise to conditions favoring the formation of iron carbides which catalyze the synthesis of hydrocarbons by the Fisher-Tropsch reaction. Modified iron and iron-free HTS catalysts have been developed to avoid these problems (49,50) and allow operation at steam to carbon ratios as low as 2.7. Kinetic and equiUbrium data for the water gas shift reaction are available in reference 51. 

Steam reforming of hydrocarbons has become the most widely used process for producing hydrogen. One of the chief problems In the process Is the deposition of coke on the catalyst. To control coke deposition, high steam to hydrocarbon ratios, n, are used. However, excess steam must be recycled and It Is desirable to minimize the magnitude of the recycle stream for economy. Most of the research on this reaction has focused mainly on kinetic and mechanistic considerations of the steam-methane reaction at high values of n to avoid carbon deposition ( L 4). Therefore, the primary objective of this studyis to determine experimentally the minimum value of n for the coke-free operation at various temperatures for a commercial catalyst. 

The noncatalytic partial oxidation of fuel oil converts petroleum feedstock into synthesis gas, C02, CH4, and H2S if any sulfur is present. This process has the ability to handle sulfur compounds without pretreatment (sulfur removal). Eliminating a processing step from steam reforming techniques, however, requires additional equipment for oxygen addition in the reactor. The expected carbon deposition problem with hydrocarbon material containing low H C ratios is limited by the use of carbon recovery and extinction recycle schemes [28], The partial oxidation of fuel oil typically operates at a temperature range of 1200-1500°C and pressures of 30-80 bars in a refractory-lined reactor. 

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