Hydrotreating Catalyst HDN Selectivity via Phosphorus Ratios
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Solution Overview
Problem
Current hydroprocessing catalysts have limited selectivity for hydrodenitrogenation (HDN) compared to hydrodesulfurization (HDS) in FCC processes, which affects the efficiency of processing heavy hydrocarbon oils and reduces catalyst life due to metal contamination.
Innovation Solution
A catalyst composition with specific mole ratios of Group VIII to Phosphorous and Group VIB metals, supported on a foraminous alumina, optimized to achieve enhanced HDN selectivity while maintaining HDS activity, characterized by a Group VIII metal to Phosphorous mole ratio of less than 0.60:1, Group VIII to Group VIB mole ratio of less than 0.45:1, and a phosphorous to Group VIB mole ratio greater than 0.23:1, with a median pore diameter between 75 Å and 95 Å.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional hydroprocessing catalysts are used to remove sulfur and nitrogen, then HDS activity is maintained, but HDN selectivity is limited
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating phosphorous along with Group VIB and Group VIII metals in specific mole ratios. This parameter change modifies the catalyst's electronic and geometric properties, enhancing HDN selectivity while maintaining HDS activity, thereby resolving the contradiction between selectivity and catalyst life
Solution Approach 2:
The patent creates a composite catalyst material combining Group VIB metals, Group VIII metals, and phosphorous on an alumina support. This composite structure synergistically combines the sulfur removal capability of Group VIB metals, the nitrogen removal capability of Group VIII metals, and the selectivity enhancement from phosphorous, achieving both high HDN selectivity and maintained HDS activity
2Productivity
If reactor temperature is increased to improve nitrogen removal, then HDN activity increases, but HDS selectivity decreases
Solution Approach 1:
Instead of changing the operating temperature parameter, the patent changes the catalyst composition parameters by incorporating phosphorous with specific mole ratios to Group VIB and Group VIII metals. This allows the catalyst to achieve high HDN activity at lower temperatures while maintaining HDS selectivity, resolving the contradiction between productivity and selectivity
3Productivity
If catalysts with high metal content are used to enhance HDN activity, then nitrogen removal improves, but metal contamination increases
Solution Approach 1:
The patent optimizes the metal content parameters by specifying precise mole ratios: Group VIII to Group VIB metal ratio of 0.1 to 0.5, and phosphorous to Group VIB metal ratio of 0.05 to 0.5. These parameter optimizations allow achieving high HDN activity with reduced metal loading, thereby minimizing metal contamination while maintaining productivity
Solution Approach 2:
Phosphorous acts as an intermediary element that enhances the nitrogen removal activity of Group VIII metals without requiring increased metal content. It modifies the catalyst surface properties and electronic structure, allowing lower metal loadings to achieve the same HDN activity, thus reducing metal contamination while maintaining productivity
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 composition significantly enhances HDN selectivity for a given HDS level, improving the tolerance to metals and extending catalyst life, thus optimizing the hydroprocessing of heavy hydrocarbon oils.
Implementation Method 1
Catalysts used in hydroprocessing processes generally comprise catalytically active metals from Groups VIB (Group 6) and Group VIII (Groups 8, 9 and 10) of The Periodic Table and are typically supported on a support, typically made predominately of alumina
Implementation Method 2
said catalyst components are carried on a foraminous support
Data Source
AI summary
Improved supported hydroprocessing catalysts, and their method of preparation useful for the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of a petroleum feedstock, including a residuum hydrocarbon feedstock are disclosed. The Catalysts contain at least one Groups VIB metal component, at least one Group VIII metal component, and a phosphorus component, supported on a foraminous support such as alumina. The supported catalysts are characterized by a specific combination of properties, namely, the Group VIII metal to Phosphorous molar ratio, the Group VIII metal to Group VIB metal molar ratio, the phosphorous component to Group VIB component molar ratio and the median pore diameter. The resulting catalysts exhibit enhanced HDN without sacrificing to any significant degree the HDS activity.