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This paper reports the application of multi-component hydrocracking catalyst grading technology in diesel hydrocracking system to increase naphtha, and studies the influence of catalyst systems with different number of graded beds on the reaction process of diesel hydrocracking. Three hydrocracking catalysts with different physicochemical properties as gradation components, the diesel hydrocracking reaction on catalyst systems of one-component, two-component and three-component graded beds with different loading sequences are carried out and evaluated, respectively. The catalytic mechanism of the multi-component grading system is analyzed. The results show that, with the increase of the number of grading beds, the space velocity of reaction on each catalyst increases, which can effectively control the overreaction process; along the flow direction of feedstock, the loading sequences of catalysts with acidity decreasing and pore properties increasing can satisfy the demand of different catalytic activity for the conversion of reactant with changing composition to naphtha, which has a guiding role in the conversion of feedstock to target products. Therefore, the conversion of diesel, the selectivity and yield of naphtha all increase significantly on the multi-component catalyst system. The research on the grading technology of multi-component catalysts is of great significance to the promotion and application of catalyst systems in various catalytic fields. [ABSTRACT FROM AUTHOR]

Figuring out rock strength plays essential roles in the sub ground mining activities, such as oil and gas well drilling and hydraulic fracturing, coal mining, tunneling, and other civil engineering scenarios. To help understand the effects of the mineralogical composition on evaluating the rock strength, this research tries to establish indirect prediction models of rock strength by specific input mineral contents for common sedimentary rocks. Using rock samples collected from the outcrops in the Sichuan Basin, uniaxial compression tests have been conducted to sandstone, carbonate, and shale cores. Combining with statistical analysis, the experimental data prove it true that the mineralogical composition can be utilized to predict the rock strength under specific conditions but the effects of mineralogical composition on the rock strength highly depend on the rock lithologies. According to the statistical analysis results, the predicted values of rock strengths by the mineral contents can get high accuracies in sandstone and carbonate rocks while no evidences can be found in shale rocks. The best indicator for predicting rock strength should be the quartz content for the sandstone rocks and the dolomite content for the carbonate rocks. Especially, to improve the evaluation accuracy, the rock strengths of sandstones can be obtained by substituting the mineral contents of quartz and clays, and those of carbonates can be calculated by the mineral contents of dolomite and calcite. Noticeably, the research data point out a significant contrast of quartz content in evaluating the rock strength of the sandstone rocks and the carbonate rocks. Increasing quartz content helps increase the sandstone strength but decrease the carbonate strength. As for shale rocks, no relationship exists between the rock strength and the mineralogical composition (e.g., the clay fractions). To provide more evidences, detailed discussion also provides the readers more glances into the framework of the rock matrix, which can be further studied in the future. These findings can help understand the effects of mineralogical composition on the rock strengths, explain the contrasts in the rock strength of the responses to the same mineral content (e.g., the quartz content), and provide another indirect method for evaluating the rock strength of common sedimentary rocks. [ABSTRACT FROM AUTHOR]