Sequential Ni-Mo and Ni-W Catalysts for Deep Distillate Hydrotreating
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Solution Overview
Problem
Conventional hydrotreating catalysts face challenges in achieving optimal performance for sulfur, nitrogen, and aromatic compound removal, with existing catalyst sequences not sufficiently increasing activity and stability to meet stringent fuel specifications.
Innovation Solution
A hydrotreating process using a sequence of a first catalyst with a nickel-molybdenum active phase on an alumina support and a second catalyst with a nickel-tungsten active phase on a silica-alumina support, both containing phosphorus and an organic compound, to enhance hydrodesulfurization, hydrodeazotation, and hydrodearomatization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single multifunctional catalyst is used to perform multiple reactions (hydrodesulfurization, hydrodenitrogenation, hydroaromatization), then device complexity is reduced, but selectivity and activity for each specific reaction deteriorate
Solution Approach 1:
The patent divides the catalyst system into three separate catalysts, each optimized for a specific function: Catalyst 1 (Ni-W on silica-alumina) for hydrodesulfurization, Catalyst 2 for hydrodenitrogenation, and Catalyst 3 for hydroaromatization. This segmentation allows each catalyst to achieve high selectivity and activity for its designated reaction while maintaining overall process efficiency.
2Productivity
If severe reaction conditions are applied to achieve high conversion in a single stage, then productivity increases, but catalyst deactivation and harmful byproducts increase
Solution Approach 1:
The patent implements a three-stage reaction process where each stage operates under optimized conditions for its specific function. This allows high overall conversion to be achieved without subjecting any single catalyst to severe conditions that would cause deactivation or unwanted byproduct formation.
Solution Approach 2:
The patent introduces an intermediate hydrorefining stage between hydrodesulfurization and hydrodenitrogenation/aromatization stages. This intermediate treatment removes poisons and protects subsequent catalysts from deactivation, enabling sustained high productivity without harmful effects.
3Manufacturing precision
If multiple reaction stages are implemented to improve selectivity, then reaction precision increases, but device complexity and processing time increase
Solution Approach 1:
The patent segments the catalytic system into three specialized catalysts, each highly selective for its specific reaction. This approach achieves superior reaction precision while keeping the overall process manageable through clear functional separation.
Solution Approach 2:
Each catalyst is designed with universal properties that enable it to perform its specific function effectively across the entire feedstock range. The Ni-W on silica-alumina catalyst, for example, provides both hydrodesulfurization activity and catalyst protection functions.
4Manufacturing precision
If multiple specialized catalysts are used for each reaction, then reaction selectivity improves, but device complexity and operation difficulty increase
Solution Approach 1:
The patent divides the catalyst system into three specialized catalysts, each optimized for a specific function: Catalyst 1 (Ni-W on silica-alumina) for hydrodesulfurization, Catalyst 2 for hydrodenitrogenation, and Catalyst 3 for hydroaromatization. This segmentation allows each catalyst to achieve high selectivity and activity for its designated reaction while maintaining overall process efficiency.
Solution Approach 2:
The patent introduces an intermediate hydrorefining stage between hydrodesulfurization and hydrodenitrogenation/aromatization stages. This intermediate treatment removes poisons and protects subsequent catalysts from deactivation, enabling sustained high productivity without harmful effects.
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 process achieves high conversions of greater than 95% for hydrodesulfurization, 90% for hydrodeazotation, and 35% for hydrodearomatization, with increased stability and activity, particularly suitable for vacuum distillate feedstocks and feedstocks with high nitrogen and aromatics.
Implementation Method 1
a catalyst based on nickel and tungsten on a silica-alumina support and a sequence of three catalysts
Implementation Method 2
the sequence of three catalysts enables hydrodesulfurization, hydrodenitrogenation and hydroaromatization reactions
Implementation Method 3
the sequence of three catalysts enables hydrodesulfurization, hydrodenitrogenation and hydroaromatization reactions
Data Source
AI summary
The invention relates to a process for the hydrotreatment of a hydrocarbon feedstock, of which at least 50% by weight of the compounds have an initial boiling point of greater than 300°C and a final boiling point of lower than 650°C, so as to obtain a hydrotreated effluent. Said process comprises the following steps: a) said hydrocarbon feedstock is brought into contact, in the presence of hydrogen, with at least one first catalyst comprising an alumina support and an active phase consisting of nickel and molybdenum; b) the effluent obtained in step a) is brought into contact, in the presence of hydrogen, with at least one second catalyst comprising a silica-alumina support and an active phase consisting of nickel and tungsten, phosphorus and an organic compound.