Hydrotreating Catalyst with Extruded Boehmite Support
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Solution Overview
Problem
Current hydrotreating catalysts used for hydrodesulfurization in petroleum refining cause a significant drop in octane number due to the hydrogenation of olefins, which is not selectively controlled, leading to a need for catalysts with improved hydrodesulfurization activity and selectivity.
Innovation Solution
A catalyst comprising an alumina support with a specific surface area between 60 and 150 m2/g, featuring cobalt, molybdenum, and phosphorus, with a molybdenum density of 3-5 atoms/nm2 and Co/Mo and P/Mo atomic ratios of 0.3-0.5 and 0.1-0.3 respectively, is developed, which is synthesized using a boehmite gel and shaped by extrusion, and treated to enhance its hydrodesulfurization selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydrotreating catalysts are used for hydrodesulfurization, then sulfur content is reduced, but octane number drops significantly due to olefin hydrogenation
Solution Approach 1:
The catalyst employs different active phases (CoMoS and NiMoS) with distinct selectivity characteristics distributed on the alumina support. The CoMoS phase provides high HDS activity while NiMoS phase contributes to olefin preservation, creating local functional differentiation that resolves the contradiction between sulfur removal and octane preservation
Solution Approach 2:
The invention optimizes critical parameters including metal surface density (0.5-3.10^4 g MoO3/m2), atomic ratios (Co/Mo: 0.3-0.5, P/Mo: 0.1-0.3), and specific surface area (60-150 m2/g). These parameter adjustments tune the catalyst's selectivity toward HDS while suppressing olefin hydrogenation, thereby maintaining octane number during desulfurization
2Productivity
If catalyst surface density of group VIB element oxide is increased to improve HDS activity, then hydrodesulfurization performance improves, but selectivity versus olefin hydrogenation may be compromised
Solution Approach 1:
The invention establishes optimal ranges for metal surface density (0.5-3.10^4 g MoO3/m2) and atomic ratios (Co/Mo: 0.3-0.5, P/Mo: 0.1-0.3). By precisely controlling these parameters, the catalyst achieves high HDS activity through sufficient metal loading while maintaining selectivity through optimized compositional ratios and the presence of phosphorus dopant
Solution Approach 2:
The catalyst combines multiple elements (Co, Mo, Ni, P) on an alumina support to create a composite material with synergistic properties. The CoMoS and NiMoS phases work together, where CoMoS provides primary HDS activity and NiMoS enhances selectivity, resolving the contradiction between activity and selectivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst achieves improved hydrodesulfurization activity with enhanced selectivity compared to olefin hydrogenation, preserving the octane number and effectively reducing sulfur content in gasoline without severe octane rating reduction.
Implementation Method 1
an alumina support obtained from alumina gel shaped by extrusion
Implementation Method 2
a heterogeneous catalyst
Implementation Method 3
catalysts based on transition metal sulphide containing a group VIB element (Cr, Mo, W) and a group VIII element (Fe, Ru, Os, Co, Rh, Ir, Pd, Ni, Pt)
Data Source
AI summary
The present invention relates to a hydrotreatment catalyst comprising a support, at least one metal selected from group VIB, and at least one metal selected from group VIII of the periodic table, wherein the group VIB metal content, expressed in terms of oxides, is of 6 to 25 wt.% relative to the total weight of the catalyst, the group VIII metal content, expressed in terms of oxides, is of 0.5 to 7 wt.% relative to the total weight of the catalyst, the support comprising at least 90 wt.% of alumina, and wherein said alumina is obtained from a mixed and extruded boehmite gel and the specific surface area of said catalyst is 60 to 250 m2/g.