Slurry Phase Hydrocracking Of Residue Research Articles

Effect of active site size in dispersed MoS2 nanocatalysts on slurry-phase hydrocracking of residue

This work investigates the influence of active site size in dispersed MoS2 on the slurry-phase hydrocracking of Merey residue (MRR). MoS2 nanocatalysts with varying morphologies were synthesized using the ligand sulfurization method, employing molybdenum oleate as the Mo precursor. The results demonstrate that mono-layered or double-layered MoS2 plates with slab sizes of 3 ∼ 10 nm can be synthesized at a sulfurization temperature of 400 °C and a sulfurization time of 0.5 h. Prolonged sulfurization time results in the growth and agglomeration of MoS2 plates, leading to multi-layered slabs with increased length and larger particle size, as well as a wider distribution range. The MoS2-0.5 (prepared with a sulfurization time of 0.5 h) exhibits superior hydrocracking activity, effectively converting resin and asphaltene into light fractions and significantly suppressing coke formation. Specifically, the conversion rates of resin and asphaltene are 51.3 wt% and 92.1 wt%, respectively, with the minimal coke yield of 0.6 wt% under conditions of 430 °C, 1 h, 7 MPa initial H2, and a catalyst dosage of 500 μg/g. The catalytic activity of the MoS2 nanocatalysts exhibits a strong correlation with their size and morphology obtained at different sulfurization times. Density functional theory (DFT) calculations reveal that MoS2 with smaller slab sizes are more beneficial for the adsorption and dissociation of H2, due to higher adsorption energy (Eads) and lower activation barrier (Ea). This facilitates the generation of sufficient active hydrogen to encourage the hydrocracking of residue and suppress coke formation.

Slurry-Phase Hydrocracking of Residue with Ultradispersed MoS2 Catalysts Prepared by Microemulsion Methods

Slurry-phase hydrocracking of vacuum residue using a dispersed catalyst has been investigated in this work. The liquid yield and coke formation in this process mostly depend upon the catalyst particle size and its distribution. Three emulsion methods, colloidal emulsion liquid (CEL), emulsion liquid membrane (ELM), and reverse micelle (RM), are used to synthesize the dispersed MoS2 catalyst. Dynamic light scattering results show that the colloidal particle of molybdenum sulfide in the RM catalyst is smaller in size and narrowly distributed in comparison to the catalysts prepared by CEL and ELM methods. Our scanning electron microscopy and transmission electron microscopy analysis results also support the smaller particle size of the active metal in the RM catalyst. Hydrotreating and hydrocracking activities of the RM catalyst are higher, and it is due to its smaller particle size and its narrow distribution. Moreover, coke formation in this catalyst is very low. It is found that the residue (550 °C+ hydro...

Slurry Phase Hydrocracking of Residue by Phosphomolybdic and Phosphotungstic Acids

Slurry phase hydrocracking of vacuum residue was studied on heteropoly acids and on super acid. In this regards, heteropoly acid of phosphomolybdic, phosphotungstic and superacid of molybdenum-antimony fluoride were used. Deep hydrocracking of residue was noticed even at moderate operating conditions for all acidic catalysts. Due to higher hydrogenating functionality of tungsten, the HDM activity of the phosphotungstic acid is higher than that of molybdenum containing acids. Even the residue hydrocracking activity of former catalyst is also high. It is also noticed from sulphur distribution of liquid product that thiophenic sulphur compounds are formed due to C-S bond cleavage at branching of condensed aromatic rings. Moreover, phosphotungstic acid gives high percentage of aromatic products whereas the considerable amount of saturate hydrocarbons is produced by phosphomolybdic acid. The coke produced by phosphotungstic acid catalyst is hard in nature indicating that extensive polymerization reaction occurs at reaction conditions. Higher H/C ratio indicates the deep hydrogenation of liquid products in presence of super acids. Instead of use superacid, tungsten based heteropoly acid can be effectively used for hydrocracking of residue.

Dispersion of Water-Soluble Catalyst and Its Influence on the Slurry-Phase Hydrocracking of Residue

Laboratory findings are presented for the dispersion process of water-soluble dispersed catalyst and the slurry-phased hydrocracking of Liaohe vacuum residue (LHVR). Optical microscopy was adopted to characterize the dispersion process, and the impacts of various factors on the process were studied by means of the particle size distribution (PSD) of catalysts, which was obtained from the micrographs using the Image-Pro Plus image analysis program. Effects of the dispersion on LHVR conversion and coke formation were then investigated in an autoclave simulating slurry-phase hydrocracking. The results indicated that the dispersion of catalyst is significantly improved by reducing the interfacial tension between the precursor solution and the feedstock, and the yield of lighter fraction (gas and gasoline), coke, content of asphaltene in bottom from products, and conversion of condensation reaction decrease to follow the decreasing interfacial tension. That is, higher dispersion of the catalyst could enhance t...