Self-Supported Ni-Mo-W Sulfide Catalyst for Naphthene Ring Opening
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Solution Overview
Problem
Conventional hydrocracking catalysts are unable to selectively open naphthenic rings without further cracking desired paraffins due to high acidity, and are sensitive to high sulfur content feeds, limiting the production of high-quality distillate fuels and lubricant base oils.
Innovation Solution
A self-supported mixed metal sulfide catalyst comprising nickel sulfide, molybdenum sulfide, and tungsten sulfide, with specific molar ratios and an organic complexing agent, is used to selectively open naphthenic rings in a feed stream with high sulfur and nitrogen content, forming a ring-opened product with increased linear paraffin functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking catalysts with high acidity are used to open naphthenic rings, then ring opening activity is improved, but selectivity deteriorates due to further cracking of desired paraffins
Solution Approach 1:
The patent changes the chemical parameters of the catalyst by using mixed metal sulfides (Ni-Mo-W) instead of conventional acidic catalysts. This parameter change transforms the catalyst's chemical nature from acidic to sulfide-based, enabling ring opening activity while maintaining selectivity and avoiding excessive paraffin cracking.
Solution Approach 2:
The patent employs a composite catalyst system combining nickel, molybdenum, and tungsten sulfides in specific ratios. This composite material approach creates synergistic effects where the combination of multiple metal sulfides provides both ring opening activity and selectivity, overcoming the limitations of single-metal or acidic catalysts.
2Manufacturing precision
If conventional noble metal hydrogenation catalysts are used for ring opening, then selectivity is improved, but sulfur tolerance deteriorates when sulfur content exceeds 10 ppm
Solution Approach 1:
The patent converts the harmful effect of sulfur into a beneficial feature by using metal sulfides as the catalyst active phase. Instead of being poisoned by sulfur as conventional noble metal catalysts are, the Ni-Mo-W sulfide catalyst is specifically designed to operate in high sulfur environments, transforming sulfur from a poison into an integral part of the catalyst's composition and operation mode.
Solution Approach 2:
The patent changes the catalyst's chemical composition parameters to metal sulfides, which fundamentally alters the catalyst's interaction with sulfur. This parameter change enables the catalyst to maintain high selectivity and activity in feeds with sulfur content up to 3000 ppm, compared to the 10 ppm limit for conventional noble metal catalysts.
3Reliability
If hydrogenation processes are used to saturate aromatic rings to naphthenes, then cetane number is improved, but API gravity deteriorates due to increased density
Solution Approach 1:
The patent extracts naphthenic rings from the hydrocarbon molecules through catalytic ring opening, converting them into linear paraffinic structures. This extraction of the cyclic structure eliminates the density penalty associated with naphthenes while preserving the saturated nature of the molecules, thereby improving API gravity without sacrificing cetane number.
Solution Approach 2:
Instead of the conventional approach of converting aromatics to naphthenes (which increases density), the patent inverts the strategy by opening naphthenic rings to produce paraffins. This inverted approach achieves the desired cetane number improvement while simultaneously improving API gravity by reducing molecular density.
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 exhibits high selectivity and sulfur/nitrogen tolerance, improving the quality of distillate fuels by reducing aromatics content and increasing cetane number, while maintaining high yields and stability.
Implementation Method 1
contacting a naphthene ring-containing feed stream under ring opening conditions with hydrogen and a self-supported mixed metal sulfide catalyst comprising nickel sulfide, molybdenum sulfide, tungsten sulfide and an organic complexing agent, thereby forming a ring-opened product
Data Source
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AI summary
A process is disclosed for opening naphthenic rings of naphthenic ring-containing compounds. Naphthene ring opening is achieved using a self-supported mixed metal sulfide catalyst comprising nickel sulfide, molybdenum sulfide, tungsten sulfide and an organic complexing agent. The catalyst is characterized as having a composition of metal components, in terms of molar ratios; as follows: 0.25≤Ni/(Ni+Mo+W)≤0.80; 0<Mo/(Ni+Mo+W)≤0.25; 0.12≤W/(Ni+Mo+W)≤0.50; and 1.5≤W/Mo≤3.0.3.