Hydrotreating Catalyst with Modified Alumina Support
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Solution Overview
Problem
Current hydrotreating catalysts face challenges in achieving high desulfurization activity, especially with refractory sulfur species, and stability when processing heavier feedstocks with high sulfur and nitrogen content, due to limitations in porous structure and uniform distribution of modifying elements on the alumina support.
Innovation Solution
The catalyst is modified by incorporating small amounts of boron, aluminum, silicon, titanium, cerium, or zirconium as oxides on the alumina support, followed by impregnation with Group VIB and Group VIII metal precursors, maintaining the porous structure and enhancing the catalytic activity through uniform distribution and chemical interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrotreating catalysts are used, then basic desulfurization activity is achieved, but high desulfurization activity for refractory sulfur species and stability with heavy feedstocks cannot be achieved
Solution Approach 1:
The patent modifies the alumina support by incorporating small amounts (0.01-2% wt) of modifying elements (boron, aluminum, silicon, titanium, cerium, or zirconium) as oxides. This changes the physico-chemical parameters of the support surface, creating uniform distribution and chemical interaction that enhances both catalyst stability and desulfurization activity, particularly for refractory sulfur species in heavy feedstocks.
Solution Approach 2:
The patent creates a composite catalyst system by combining modified alumina support (with incorporating modifying elements) with Group VIB and Group VIII metals. The composite structure of alumina + modifying elements + active metals provides synergistic effects that simultaneously improve catalyst stability and desulfurization activity, resolving the contradiction between reliability and productivity.
2Productivity
If modifying elements are incorporated on alumina support, then catalytic activity is enhanced, but uniform distribution and chemical interaction are difficult to achieve
Solution Approach 1:
The patent optimizes the concentration parameter of modifying elements to very low levels (0.01-2% wt), which enables uniform distribution across the alumina support surface. This parameter change prevents aggregation and promotes homogeneous chemical interaction, achieving both high catalytic activity and precise manufacturing uniformity.
Solution Approach 2:
The modifying elements are distributed uniformly across the alumina support surface, creating consistent local properties throughout the catalyst. This uniform local quality ensures that all regions of the catalyst exhibit similar enhanced activity, achieving precise manufacturing control while maintaining high productivity.
3Productivity
If alumina support is modified with modifying elements, then desulfurization to ultra-low sulfur levels is achieved, but porous structure may be affected
Solution Approach 1:
The patent carefully controls the amount of modifying elements at very low concentrations (0.01-2% wt), which is sufficient to enhance desulfurization activity to ultra-low sulfur levels while maintaining the porous structure of alumina. This parameter optimization ensures that the beneficial effects on activity are achieved without compromising structural stability.
Solution Approach 2:
The patent uses alumina as a porous support material and modifies it with trace amounts of modifying elements that do not block the pores. The porous structure is preserved, allowing reactant diffusion and product egress, while the modifying elements enhance the catalytic activity on the pore surfaces, achieving ultra-low desulfurization without structural degradation.
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
This approach results in a highly active and stable hydrotreating catalyst capable of desulfurizing feedstocks to ultra-low sulfur levels, even in the presence of significant nitrogen species, with improved resistance to inhibition and sustained performance.
Implementation Method 1
chemical interaction of active metals with the support surface
Implementation Method 2
impregnation with Group VIB and Group VIII metal precursors
Implementation Method 3
hydrodesulfurization activity for employing for the desulfurization of hydrocarbon streams
Implementation Method 4
C—S bond cleavage as compared to the conventional direct desulfurization through hydrogenolysis reaction
Implementation Method 5
layered clusters of molybdenum disulfide chemically modified with nickel or cobalt with coordinately unsaturated edge sites as active sites responsible for hydro desulfurization activity
Implementation Method 6
The basal plane of the molybdenum disulfide clusters has hydrogenation-active edge metallic sites which enable hydrogenation of refractory sulfur species and aromatics
Data Source
AI summary
The current invention provides a hydrotreating catalyst comprising of metals of at least one each from Group VIB, preferably molybdenum and Group VIII, preferably nickel, of the periodic table supported on alumina modified with small amounts of modifying elements well dispersed on the surface so as to retain the physico-chemical characteristics of the support and result in high performance for hydrodesulphurization catalyst, and a commercially viable process for producing such a catalyst. The present invention also discloses a commercially viable method for modifying alumina in the powder form without affecting the porous structure of the support obtained.