Trimetallic catalyst supported on modified alumina for upgrading and hydrotreating of petroleum fractions

Abstract

Currently, continuous worldwide concern is paid toward the development of efficient and cost-effective processes for the removal of toxic and hazardous components, such as sulfur and nitrogen compounds, from fossil fuel fractions. In an agreement with this trend, this thesis reports enhanced disposal of sulfur, nitrogen and aromatic compounds from both heavy vacuum gas oil (HVGO) and diesel fuel feedstocks using various techniques. Particularly, adsorptive removal of such compounds using novel adsorbents made of blending polystyrene (waste or synthesized polymer) with imidazole and its derivatives had been carried out at various operating conditions. The essential characteristics of prepared adsorbents were firstly investigated using Fourier transform infrared (FT-IR), BET surface area analysis, scanning electron microscopy (SEM) and molecular weight. Then, these adsorbents could successfully attain reasonable eliminations for both sulfur and nitrogen compounds. However, maximum removals of 40 and 75 wt. % for sulfur and nitrogen compounds respectively (from heavy vacuum gas oil) at 60oC, 6 h and adsorbent-to-feed ratio of 1:5 had been obtained by butyl-Imidazole blended waste polystyrene (WPS). The sulfur and nitrogen compounds removals could be respectively increased to 46 and 85 Wt. %, at same operating conditions, using the same composition of adsorbent while introducing a synthesized polystyrene instead of WPS. This adsorbent could also achieve respective percentages of sulfur and nitrogen removals (from diesel fuel feedstock) equal 50.91and 87.35. Another technique had been also employed during this thesis for the purpose of sulfur, nitrogen and aromatic compounds removal from the previously stated petroleum fractions. Specifically, catalytic hydrotreatment (HT) using tri-metallic catalysts supported on different structures (CeO2 and Al2O3) had been performed. Feasibility of doping different percentages of CeO2 to Al2O3 to obtain