The impact of the water phase in the gasoil fraction on the CoMo hydrotreating catalyst's performance

The effect of the presence of water in the feedstock on the activity of CoMoP/Al2O3 catalysts modified with La during the hydrotreating of the diesel fraction was studied. A total of four experiments were carried out: in the first there was no water, in the other two experiments water was supplied to the reactor mixed with gasoil for a long and short period of time, and in the fourth, water was first supplied to the reactor, and then the reaction was carried out only with the diesel fraction. The catalysts were studied using the nitrogen adsorption-desorption method, UV-vis spectroscopy, FTIR, HRTEM, EDX, XPS, XRD. The activity of the catalysts was judged by the residual content of sulfur and nitrogen in the samples after the reaction. It was found that the addition of water to the gasoil fraction leads to a strong deactivation effect on the catalyst in targeted hydrotreating reactions due to structural changes in the active component of the catalyst and its distribution on the support surface, the decrease in number of active sites due to the oxidation of the active component edges and the segregation of cobalt atoms with a possible incomplete recovery of catalytic activity due to re-sulfiding after water supply stops.