Hydrocracking Catalyst for Polycyclic Ring Opening
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Solution Overview
Problem
Current hydrocracking catalysts fail to effectively open polycyclic aromatic and aliphatic rings while preserving the original carbon atoms, leading to suboptimal diesel selectivity and cetane value in hydrocarbon streams.
Innovation Solution
A catalyst composition featuring a support of amorphous silica-alumina and non-zeolitic alumina with specific silicon-to-aluminum ratios, combined with platinum and other hydrogenation metals, is used to maximize ring opening of polycyclic compounds without cracking off alkyl groups, thereby producing higher cetane number distillate products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrocracking catalysts are used to crack polycyclic rings, then ring opening occurs, but the original carbon atoms are truncated to smaller paraffins and aromatics, reducing diesel selectivity
Solution Approach 1:
The patent changes the chemical parameters of the catalyst by using a specific amorphous silica-alumina composition with controlled Si/Al ratios (0.5 to 2.0) and sulfur content (0.1 to 5.0 wt%), along with specific metal components (Pt, Pd, Ni, Mo, W) in defined ratios. These parameter changes enable the catalyst to open polycyclic rings while preserving carbon atoms, converting them to alkyl naphthenes and paraffins in the diesel range rather than truncating to naphtha-range molecules.
Solution Approach 2:
The patent employs a composite catalyst material consisting of amorphous silica-alumina as the base support combined with specific metal components (platinum, palladium, nickel, molybdenum, or tungsten) and controlled sulfur content. This composite structure creates synergistic effects that enable selective ring opening while maintaining carbon atom integrity and achieving high diesel-range product selectivity.
2Quantity of substance
If higher conversion to diesel-range products is achieved, then cetane value improves, but more severe cracking conditions produce excessive naphtha and light gas
Solution Approach 1:
The patent utilizes parameter changes in the catalyst composition (amorphous silica-alumina with specific Si/Al ratios and metal content) to shift the reaction pathway. This enables achieving high conversion to diesel-range products (alkyl naphthenes and paraffins) while suppressing excessive cracking to naphtha and light gas, thus improving cetane value without generating harmful over-cracking products.
Solution Approach 2:
The patent converts the harmful effect of over-cracking into a beneficial outcome by using the amorphous silica-alumina catalyst with controlled sulfur content to selectively manage the cracking process. The catalyst promotes desirable ring opening and hydrogenation reactions that produce high-cetane diesel-range products while minimizing unwanted naphtha and light gas formation, effectively turning potential harmful over-cracking into a controlled beneficial process.
3Productivity
If ring opening is performed at higher temperatures to increase conversion, then more polycyclic rings are opened, but energy consumption increases and unwanted cracking occurs
Solution Approach 1:
The patent changes the catalyst parameters (amorphous silica-alumina composition with Si/Al ratios of 0.5 to 2.0, metal content, and sulfur levels) to enhance catalytic activity and selectivity. This enables achieving high conversion rates for ring opening at lower temperatures, thereby reducing energy consumption while maintaining high productivity and avoiding unwanted cracking side reactions.
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 higher ring opening efficiency at lower temperatures, maximizing conversion to valuable diesel-range products with improved cetane value and volumetric yields, while minimizing the production of less valuable naphtha or light gas.
Implementation Method 1
Ring opening typically requires aromatic rings to be saturated before the ring can be opened
Implementation Method 2
Hydrocracking is a hydroprocessing process in which hydrocarbons crack in the presence of hydrogen and hydrocracking catalyst
Data Source
AI summary
A catalyst composition comprising a support comprising a mixture of amorphous silica-alumina and non-zeolitic alumina comprising no more than 75 wt % amorphous silica-alumina and having a ratio of moles of silicon to moles of aluminum in the range of about 0.05 to about 0.50. A first hydrogenation metal comprising platinum, a second hydrogenation metal from Group VIIB or Group VIII of the Periodic Table other than platinum and an optional third metal from Group IA of the Periodic Table may be deposited on the support. The ratio of moles of silicon to the moles of the first hydrogenation metal, the second hydrogenation metal and the optional third metal on the support may be between about 15 and about 75.