Deactivation of WNiPd/TiO 2Al 2O 3 catalyst during the upgrading of LCO

Abstract

The deactivation of a novel catalyst during the production of a high-quality low-emission diesel component has been studied experimentally in a hydrotreating microplant. This process is compared with a commercial operation that used a conventional HDT catalyst. Catalysts were tested by incrementing temperature as a function of cycle length to keep the sulfur constant in the product, maintaining all other operating conditions constant. Spent catalysts were characterized using solid 13CNMR and XPS spectroscopy, pyridine adsorption, GC–MS of the coke extracted, and chemical analysis. Effective pore diffusivity was measured with pentane, and the catalyst activity and selectivity were measured with LCO and probe molecules to verify naphthenic ring opening capability. An important decline in hydrogenation and ring opening activity was detected along the cycle length due to acid site deactivation. The deactivation is attributed to LCO poly-aromatics adsorption on a particular type of acid site. A commercially deactivated HDT catalyst that operated with LCO presents a similar type of coke to that of the pilot plant.