Hydrotreating of Atmospheric Gas Oil and Co-Processing with Rapeseed Oil Using Sulfur-Free PMoCx/Al₂O₃ Catalysts

Abstract

Sulfur-free molybdenum carbides have the potential to replace the conventional sulfided catalysts used for hydrotreating. For these catalysts, it is not necessary to add sulfur to maintain their activity. This fact makes it worthwhile to continue working on improving their hydrotreating efficiency. According to our previous studies, the addition of Co or Ni promotes the hydrotreating activity, but only significant in the case of hydrodesulfurization efficiency (up to 30%). To increase the hydrodenitrogenation efficiency, other promoters, such as phosphorus, can be added. However, most of the published studies do not focus on coprocessing or only on hydrotreating of gas oil model molecules at a laboratory scale. In this paper, we build on our previous research by studying five sulfur-free phosphorus-modified MoCx/Al 2 O 3 catalysts (0.5, 1.5, 2.5, 3.5, and 4.5 wt %) for the hydrotreating of atmospheric gas oil and co-processing with rapeseed oil (5, 10, and 25 wt %) under industrial conditions (330−350 °C, 5.5 MPa, WHSV 1−2 h −1 ). A phosphorus content up to 1.5 wt % promoted the hydrodesulfurization (5− 10%) and the hydrodenitrogenation (10−25%) efficiencies of catalysts. Moreover, the triglycerides addition did not significantly decrease the catalyst activity during co-processing. Therefore, our results enable us to define the range of phosphorus addition that enhances MoCx activity using industrial conditions and commercial feedstocks, pointing the way to develop a suitable and sulfur-free alternative to conventional hydrotreating catalysts.

Phonolite Material as Catalyst Support for the Hydrotreatment of Gas Oil and Vegetable Oil Type Feedstocks

“…The catalyst experiments were executed similarly to the authors’ experiments for testing catalytic materials in a continuous regime [ 32 ]. The procedure is described as follows.…”

Experimental Evaluation of Hydrotreated Vegetable Oils as Novel Feedstocks for Steam-Cracking Process

“…Although the current article is focused on the HVOs utilization in the steam-cracking process, not the HVOs' preparation, here we provide a brief description of HVOs' origin, including characterization of vegetable oils, prepared HVOs, and hydrotreatment conditions. However, all the HVO preparation procedures were already published in the previous paper [21]. The feedstocks used for the HVOs' preparation were rapeseed oil (RSO), sunflower oil (SFO), and used cooking oil (UCO).…”

“…Table 1 shows the basic characterization of these materials. The hydrotreating of vegetable oils to produce HVOs was performed in the same unit used by the authors in previous co-hydroprocessing experiments [21]. The unit is placed in the experimental facility of ORLEN UniCRE a.s., Litvínov-Záluží, Czech Republic.…”

Evaluation of Time-on-Stream Deactivation Models with Effectiveness Factors for Industrial Feedstock Hydrotreating in Bench-Scale Tests

“…Hydrotreating (HDT), in general, is designed to remove sulfur, nitrogen, saturated olefinic, and aromatic compounds from a wide range of raw materials that can be hydrotreated, from fossil fuels such as residue feedstock to vegetable oils. − Typically, trickle bed reactors (TBR) are used where hydrogen and hydrocarbons concurrently flow downward over a fixed bed of catalyst particles, and the dissolved hydrogen and hydrocarbon molecules diffuse through the catalyst surface to find the distributed active sites. − Variables such as system pressure, ratio H 2 /oil, temperature, mass flows, and catalyst composition must be monitored and controlled in industrial units to fulfill the product specification demands. , Furthermore, the requirement to carry out bench-scale tests that yield representative data of the industrial hydrotreating process requires methodologies and approaches, such as the evaluation of fluid hydrodynamics, as reported by Gierman …”

“…6−8 Variables such as system pressure, ratio H 2 /oil, temperature, mass flows, and catalyst composition must be monitored and controlled in industrial units to fulfill the product specification demands. 9,10 Furthermore, the requirement to carry out bench-scale tests that yield representative data of the industrial hydrotreating process requires methodologies and approaches, such as the evaluation of fluid hydrodynamics, as reported by Gierman. 11 Various parameters are fundamental to the efficiency of the hydrotreating process, such as the effectiveness factor (η), which combines reaction kinetics with transport phenomena.…”