Hydrotreatment Followed by Oxidative Desulfurization and Denitrogenation to Attain Low Sulphur and Nitrogen Bitumen Derived Gas Oils

Abstract

To lower the sulphur content below 500 ppm and to increase the quality of bitumen derived heavy oil, a combination of hydrotreating followed by oxidative desulfurization (ODS) and oxidative denitrogenation (ODN) is proposed in this work. NiMo/γ-Al2O3 catalyst was synthesized and used to hydrotreat heavy gas oil (HGO) and light gas oil (LGO) at typical operating conditions of 370–390 °C, 9 MPa, 1–1.5 h−1 space velocity and 600:1 H2 to oil ratio. γ-Alumina and alumina-titania supported Mo, P, Mn and W catalysts were synthesized and characterized using X-ray diffractions, N2 adsorption-desorption using Brunauer–Emmett–Teller (BET) method, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). All catalysts were tested for the oxidation of sulphur and nitrogen aromatic compounds present in LGO and HGO using tert-butyl hydroperoxide (TBHP) as oxidant. The oxidized sulphur and nitrogen compounds were extracted using adsorption on activated carbon and liquid-liquid extraction using methanol. The determination of oxidation states of each metal using XPS confirmed the structure of metal oxides in the catalyst. Thus, the catalytic activity determined in terms of sulphur and nitrogen removal is related to their physico-chemical properties. In agreement with literature, a simplistic mechanism for the oxidative desulfurization is also presented. Mo was found to be more active in comparison to W. Presence of Ti in the support has shown 8–12% increase in ODS and ODN. The MnPMo/γ-Al2O3-TiO2 catalyst showed the best activity for sulphur and nitrogen removal. The role of Mn and P as promoters to molybdenum was also discussed. Further three-stage ODS and ODN was performed to achieve less than 500 ppm in HGO and LGO. The combination of hydrotreatment, ODS and ODN has resulted in removal of 98.8 wt.% sulphur and 94.7 wt.% nitrogen from HGO and removal of 98.5 wt.% sulphur and 97.8 wt.% nitrogen from LGO.

Bimetallic CoCu-ZIF material for efficient visible light photocatalytic fuel denitrification

“…9,10 Currently, NCCs in fuel are usually removed by hydro-denitrication (HDN), which consumes expensive hydrogen and requires high temperature (range from 300 to 400 C) and high-pressure conditions (range from 30 to 130 atmospheres). 11,12 The process is not economical. Photocatalysis technology is a kind of technology with low energy consumption and mild conditions, which has attracted signicant attention.…”

Assembly of a coordination polymer with sulphate-capped pentamolybdate units and copper: synthesis, structure, magnetic and catalytic studies

“…S11 in the ESI †] for ODS is based upon previous literature reports. 110,111 The reaction is expected to proceed via the coordination of TBHP to the catalyst with a nucleophilic attack to polarize the terminal Mo-O bond, thereby enhancing the electrophilicity of peroxide oxygen of the oxidant. In the second step, the oxidation cycle is initiated by a nucleophilic attack of sulphur in DBT on electropositive oxygen to form DBT sulfoxide (DBTO).…”

Review of Adsorptive Desulfurization of Liquid Fuels and Regeneration Attempts

“…Overview of desulfurization techniques. ,− [The bottom right image is reproduced with permission from ref . Copyright 2017, Elsevier, Ltd.]…”