Optimization of grading guard systems for trapping of particulates to prevent pressure drop buildup in gas oil hydrotreater

The loaded acid−base bifunctional catalysts exhibit good catalytic performance in the synthesis of methyl methacrylate via aldol condensation of methyl propionate with formaldehyde, but they still suffer from deactivation caused by coke deposition. In this paper, coke deposition as well as consequential deactivation behavior of Cs/SiO 2 catalyst loaded with various amounts of Al was investigated under different reactant compositions by using nuclear magnetic resonance, thermogravimetric, Brunauer−Emmett−Teller, and Raman analysis. As a result, coke on the catalyst was characterized by amorphous coke deposition, which was mainly composed of polycyclic aromatic hydrocarbons and aliphatic substances. Al added to the 10Cs/SiO 2 catalyst significantly reduced the amount of coke deposition and inhibited the C/H ratio of coke. Appropriate amounts of Al and reactant compositions could ultimately increase the stability of the catalyst. Moreover, the kinetics of coke deposition observed on the Al−Cs/SiO 2 catalyst was studied. It was found that the Voorhies equation modified using the variables of reaction temperature and reactants composition could accurately forecast coke accumulation on the 3.5Al-10Cs/SiO 2 catalyst under specific conditions.

Section: Resultsmentioning

confidence: 99%

Unraveling the Coking and Deactivation Behavior of Al–Cs/SiO₂ Catalyst in the Aldol Condensation of Methyl Propionate with Formaldehyde

Ran,

Zhu,

Zhang

et al. 2024

“…5 Also, there is a notable restriction to the available flow channels through the packing, which results in the pressure drop across the system increasing. 6 As these issues propagate, there is an eventual need to shut down the reactor to clean or replace the packing. This results in more catalyst waste being generated, economic loss due to downtime, and a reduced treated oil quality as the catalyst deactivates during this cycle.…”

Section: Introductionmentioning

confidence: 99%

“…Early catalyst deactivation can occur through the plugging of pore channels, restricting the available active sites . Also, there is a notable restriction to the available flow channels through the packing, which results in the pressure drop across the system increasing . As these issues propagate, there is an eventual need to shut down the reactor to clean or replace the packing.…”

Section: Introductionmentioning

confidence: 99%

Impact of Fine Solids on Hydrotreating of Bitumen-Derived Gas Oil

Polischuk

Vedachalam

Eleeza

et al. 2023

Bitumen-derived gas oils that enter hydrotreaters contain fine solids such as minerals, heavy metals, and coke. The deposition of these fines will eventually restrict the flow and result in pressure buildup across the hydrotreater, which eventually necessitate the premature shutting down of the reactor system. To determine if certain types of fine particles had a greater detriment to the hydrotreating process, a series of experiments were performed by accelerated fine deposition in a trickle bed catalytic reactor under industrial conditions using bitumen-derived light gas oil. Kaolinite, montmorillonite, pyrite, and petroleum coke fines had no significant impact on the catalyst activity and catalyst deactivation toward hydrodenitrogenation (HDN), hydrodesulfurization (HDS), and hydrodearomatization. Unlike the above fines, iron(III)oxide was found to convert into FeS under hydrotreating conditions, which provided a promoting effect for HDN and HDS reactions. When comparing the trends in pressure drop across the catalyst bed, there was a delayed period during the initial fine deposition where no change in pressure drop was observed, followed by an exponential increase in pressure due to the decrease in bed porosity. The difference found between these fines was the length of this delayed period, with iron(III)oxide and petroleum coke having the longest periods of no pressure growth. From inductively coupled plasma, scanning electron microscopy with energydispersive spectroscopy, X-ray diffraction, and Brunauer−Emmett−Teller analysis of the fresh and spent catalysts, it was determined that the deposition of all fines occurred within the packing material in the preheating zone, with only petroleum coke and iron(III)oxide fines being found on the surface of the catalysts.

“…These fine particles are especially prevalent if the bitumen source of HGO was obtained from surface-mined oil sands compared to if it was obtained through in situ techniques such as steam-assisted gravity drainage . These particles escape capture by upstream filters owing to their small size (<20 μm) and enter along with the feed into hydrotreaters. , The consequence of the presence of these fine particles is their eventual deposition in the catalyst bed during hydrotreating, causing catalyst deactivation and reduction in the bed porosity, which manifests as pressure build-up. , The pressure build-up has several negative impacts including overexploitation of recycling compressors, channeling of feed flow, high radial temperature spread, and the eventual premature shutdown, which limits packed bed reactor run time. ,, …”

Section: Introductionmentioning

confidence: 99%

“…5,7 The consequence of the presence of these fine particles is their eventual deposition in the catalyst bed during hydrotreating, causing catalyst deactivation and reduction in the bed porosity, which manifests as pressure build-up. 8,9 The pressure build-up has several negative impacts including overexploitation of recycling compressors, channeling of feed flow, high radial temperature spread, and the eventual premature shutdown, which limits packed bed reactor run time. 5,10,11 Clay minerals represent a majority of the fine particles present in gas oil feeds, accounting for about 65% of fine particles captured in the catalyst bed of a typical coker gas oil hydrotreater.…”

Section: Introductionmentioning

confidence: 99%

Deposition of Fine Particles during Hydrotreating of Oil Sands Bitumen-Derived Heavy Gas Oil in a Packed Bed Reactor: Impact of Process Parameters and Surface Charge

Eleeza

Vedachalam

Boahene

et al. 2021

Heavy gas oil feed in a packed bed reactor was used to study the influence of temperature (370−400 °C), pressure (1000− 1400 psig), and liquid hourly space velocity (LHSV) (0.5−2 h −1 ) on the deposition of fines (asphaltene-coated kaolin) during hydrotreating. The effects of surface charge on fines deposition on the catalyst bed were also investigated. The study showed that LHSV was the only factor with an individual effect on deposition, where increasing LHSV resulted in a decrease in fines deposition. Contrastingly, pressure and temperature showed interactive effects with a combination of high temperature (>380 °C) and low pressure (<1250 psig) or low temperature (<390 °C) and high pressure (>1150 psig), resulting in minimal deposition. These combinations of temperature and pressure also coincided with the region of high hydrodesulfurization, suggesting the impact of fines deposition on catalyst activity. Opposite surface charges possessed by fines and the catalyst created an attractive force that contributed to fines deposition during hydrotreating.