Relations between coke deposition and activity of HDS catalysts. [Hydrodesulfurization (HDS)]

Coke deposition due to degradation of 1,3-butadiene at 400 degrees C was examined employing supported molybdate hydrocracking catalysts, with and without promoters and with and without presulfiding. Initial hydrodesulfurization activity behavior of the catalysts was also examined. Coke deposition was found to increase as a function of catalyst composition and the type of diluting gas (He or H/sub 2/). With oxide catalysts, such as MoO/sub 3/ and NiO-MoO/sub 3/, the deposition of coke on the non-impregnated support is not affected by the type of diluting gas. It was also found that the supported MoO/sub 3/ catalyst produced more coke than the support alone in either H/sub 2/ or He atmospheres at all deposition times. Coke formation on sulfide catalysts showed a similar behavior to that of the oxide catalysts. The quantity of coke, however, was significantly smaller in all cases except on the support. (JMT)