PETR 5 |
| The condensation of polyaromatic hydrocarbons (PAH) often is cited as a mechanism for coke-induced catalyst deactivation in hydroprocessing units. Such condensation reactions are inhibited by PAH saturation, which explains why high partial pressures of hydrogen inhibit deactivation. This paper describes a simple system designed to model, thermochemically, the competition between these two types of reactions. The system comprises naphthalene, tetralin, decalin, chrysene and hydrogen. Supposedly, the formation of chrysene represents the generation of a coke precursor. The calculations show the change in equilibrium concentrations as conditions change from 100 to 3000 psig and 400 to 1500 °F. As expected, decalin is favored by high pressure and low temperature, and naphthalene is favored by high temperature and low pressure. But interestingly, our calculations also predict small but significant amounts of chrysene even at moderate pressures and temperatures. |
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2nd International Symposium on Hydrotreating/Hydrocracking Technologies
8:30 AM-11:50 AM, Sunday, 10 September 2006 Palace -- Presidio Room, Oral
Division of Petroleum Chemistry |