Hydrocracking of Hydrocarbon (II)

Abstract

The hydrocracking of the “Dry Solvent” (b. p.151-193°C), the paraffinic refinery oil of the petroleum, was studied in a conventional fixed-bed down flow system over the temperature range from 300° to 500°C, and under pressure of 50 and 100 kg/cm2, in order to clarify the effect of carbon number of the hydrocarbon on the reactivities. The gasification of the “Dry Solvent” by hydrocraking was a little bit harder than that of hexane. The activities of the catalysts were in the same order as in the case of “Hexane”, i. e., nickel>> nickel-tungsten sulfide>> tungsten sulfide> molybdenum sulfide> silica-alumina. The nickel catalyst produced methane as a major product in-dependent of the degree of gasification, and only small amounts of the intermediate pro-ducts, such as ethane, propane, were formed. On the other hand, tungsten molybdenum and nickel-tungsten sulfide catalysts produce not only methane but other saturated hydro-carbons of the carbon number of two, three and four, as was observed in the hydrocracking of “Hexane”. The reaction path is expected to be the same irrespective of the difference of the carbon number. The decrease in the activity of the nickel-tungsten sulfide catalyst at the early stages was not observed. The main active site of this catalyst is co-existing point of nickel-and tungsten components. The addition of alkali decreases the surface area, resulting the decrease in the activity. The solid acid-character of the surface is expected to have little contribution to the hydrocracking reaction.