Phosphorus-Sodium Catalyst for Selective Hydrodesulfurization
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Solution Overview
Problem
Current hydrotreating processes for gasoline cuts from fluidized-bed catalytic cracking units face challenges in reducing sulfur content without significantly lowering the octane number, as they often hydrogenate olefins, which is undesirable.
Innovation Solution
A catalyst comprising a group VIB element, a group VIII element, phosphorus, and an alumina support with specific sodium and phosphorus ratios, which enhances selectivity and activity in hydrodesulfurization, allowing for effective sulfur removal without substantial hydrogenation of olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydrotreating catalysts are used to reduce sulfur content, then sulfur removal efficiency is improved, but octane number decreases due to olefin hydrogenation
Solution Approach 1:
The invention changes the chemical composition parameters of the catalyst by incorporating specific amounts of phosphorus (0.1-5% P2O5) and sodium (50-2000 ppm Na2O), and by optimizing the P/Na molar ratio (1.5-300). This modifies the catalyst's surface properties and electronic structure, enabling selective hydrodesulfurization while suppressing olefin hydrogenation, thus resolving the contradiction between sulfur removal efficiency and octane number preservation
Solution Approach 2:
The invention creates a composite catalyst system combining group VIB metal (molybdenum or tungsten), group VIII metal (cobalt or nickel), phosphorus, and sodium on an alumina support. This multi-component composite structure synergistically enhances hydrodesulfurization activity while improving selectivity against olefin hydrogenation, thereby achieving both high sulfur removal and octane preservation
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 improves hydrodesulfurization performance by maintaining high selectivity and activity, thereby reducing sulfur content in gasoline cuts while minimizing the loss of octane number, thus meeting stringent sulfur specifications.
Implementation Method 1
a process for the hydrodesulfurization of a sulfur-containing olefinic gasoline cut
Implementation Method 2
catalyst comprising at least one element from group VIB, at least one element from group VIII, phosphorus, sodium and a support comprising alumina
Data Source
AI summary
Catalyst comprising an active phase based on at least one group VIB metal, at least one group VIII metal, phosphorus, sodium and an alumina-based support, the sodium content being between 50 and 2000 ppm by weight in the form of Na—O relative to the total weight of said catalyst, and the molar ratio of phosphorus to sodium being between 1.5 and 300.