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13 pages, 915 KiB

Open AccessArticle

Hydrocracking of Heavy Vacuum Gas Oil with Petroleum Wax

by Olga Pleyer, Iva Kubičková, Aleš Vráblík, Daniel Maxa, Milan Pospíšil, Michal Zbuzek, Dominik Schlehöfer and Petr Straka

Catalysts 2022, 12(4), 384; https://doi.org/10.3390/catal12040384 - 30 Mar 2022

Cited by 5 | Viewed by 7995

Abstract

Petroleum heavy vacuum gas oil (HVGO) containing 10 wt.% of petroleum wax was hydrocracked at 390–430 °C and under the pressure of 18 MPa over a Ni W/amorphous silica-alumina catalyst in a continuous-flow fixed-bed reactor. The hydrocracking of a reference feed (neat HVGO) was carried out under the same reaction conditions. The physico-chemical properties of primary products obtained via laboratory atmospheric-vacuum distillation (heavy naphtha, middle distillates and distillation residue) were evaluated. Most products prepared from the mixed feedstock had a similar or lower density and sulfur content than the products obtained from the hydrocracking of the neat HVGO. The heavy naphtha fractions obtained from mixed feedstock contained slightly more n-alkanes and iso-alkanes and less naphthenes and aromatics. Similarly, middle distillates obtained from the mixed feedstock contained slightly more n-alkanes and less aromatics and had cetane index higher by up to 2 units. Full article

(This article belongs to the Topic Synthesis, Characterization and Performance of Materials for a Sustainable Future)

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14 pages, 4125 KiB

Open AccessArticle

Optimization Study on Enhancing Deep-Cut Effect of the Vacuum Distillation Unit (VDU)

by Qibing Jin, Ziming Li, Zhicheng Yan, Bin Wang and Zeyu Wang

Processes 2022, 10(2), 359; https://doi.org/10.3390/pr10020359 - 14 Feb 2022

Cited by 4 | Viewed by 7198

Abstract

The vacuum distillation unit (VDU) is the key unit to produce vacuum gas oil and vacuum residue, which has a very important impact on the downstream secondary processing units. The optimization of deep-cut vacuum distillation seeks to improve the yield of heavy vacuum gas oil (HVGO) and its dry point temperature, which is related to the economic benefits of the refinery. In this study, we first established a simple model of a VDU by using the Aspen HYSYS Process simulation software. Then, we built a rigorous model with fast convergence by using the initial values obtained by the simple model. The rigorous model can accurately reflect the refinery’s operation and can make predictions. Then, based on the rigorous model, we increased the flash section temperature (FST) to 420 °C and the steam flow rate (SFR) of the stripping to 26 t/h. We eventually increased the yield of HVGO by 6.3 percentage points to 43.4%, while increasing its D86 95%-point temperature by 31.9 °C to 570.9 °C. In this way, the refinery can effectively optimize the deep-cut vacuum distillation and obtain greater economic benefits. Full article

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19 pages, 2544 KiB

Open AccessArticle

Heavy Vacuum Gas Oil Upregulates the Rhamnosyltransferases and Quorum Sensing Cascades of Rhamnolipids Biosynthesis in Pseudomonas sp. AK6U

by Sarah A. Alkhalaf, Ahmed R. Ramadan, Christian Obuekwe, Ashraf M. El Nayal, Nasser Abotalib and Wael Ismail

Molecules 2021, 26(14), 4122; https://doi.org/10.3390/molecules26144122 - 6 Jul 2021

Cited by 5 | Viewed by 2705

Abstract

We followed a comparative approach to investigate how heavy vacuum gas oil (HVGO) affects the expression of genes involved in biosurfactants biosynthesis and the composition of the rhamnolipid congeners in Pseudomonas sp. AK6U. HVGO stimulated biosurfactants production as indicated by the lower surface tension (26 mN/m) and higher yield (7.8 g/L) compared to a glucose culture (49.7 mN/m, 0.305 g/L). Quantitative real-time PCR showed that the biosurfactants production genes rhlA and rhlB were strongly upregulated in the HVGO culture during the early and late exponential growth phases. To the contrary, the rhamnose biosynthesis genes algC, rmlA and rmlC were downregulated in the HVGO culture. Genes of the quorum sensing systems which regulate biosurfactants biosynthesis exhibited a hierarchical expression profile. The lasI gene was strongly upregulated (20-fold) in the HVGO culture during the early log phase, whereas both rhlI and pqsE were upregulated during the late log phase. Rhamnolipid congener analysis using high-performance liquid chromatography-mass spectrometry revealed a much higher proportion (up to 69%) of the high-molecularweight homologue Rha–Rha–C₁₀–C₁₀ in the HVGO culture. The results shed light on the temporal and carbon source-mediated shifts in rhamonlipids’ composition and regulation of biosynthesis which can be potentially exploited to produce different rhamnolipid formulations tailored for specific applications. Full article

(This article belongs to the Special Issue Protein-Protein Interactions 2021)

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