Sequential NiMo and NiMoW Catalysts for Deep Diesel Hydrotreating
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Solution Overview
Problem
Existing hydrotreating catalysts face challenges in achieving high aromatic saturation activity, hydrodesulfurization, and hydrodenitrogenation efficiency, particularly for ultra-low sulfur diesel production, and often require sequential use of catalysts optimized for specific reactions, leading to inefficiencies and high metal content.
Innovation Solution
A hydrotreating process using a sequence of catalysts, where a first catalyst with a nickel-molybdenum active phase is followed by a second catalyst with a nickel-molybdenum-tungsten-phosphorus active phase, with a specific volume distribution of 50-90%:10-50% for the first and second reaction sections, enhancing synergistic activity and stability for aromatics hydrogenation, desulfurization, and denitrogenation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single catalyst optimized for hydrodesulfurization is used, then sulfur removal efficiency is improved, but aromatic saturation activity and hydrodenitrogenation performance deteriorate
Solution Approach 1:
The catalytic system is segmented into two distinct catalysts: a first catalyst (NiMo-based) optimized for hydrodesulfurization and hydrodenitrogenation, and a second catalyst (NiMoWP-based) optimized for aromatic saturation. This segmentation allows each catalyst to perform its specialized function at high efficiency, resolving the contradiction between sulfur removal and aromatic saturation activities
Solution Approach 2:
The first NiMo-based catalyst serves multiple functions by simultaneously providing both hydrodesulfurization and hydrodenitrogenation activities. This multi-functionality reduces the need for multiple specialized catalysts while maintaining high performance across different reaction types
2Manufacturing precision
If sequential catalysts optimized for specific reactions are used, then reaction specificity is improved, but device complexity and metal content increase
Solution Approach 1:
The first NiMo-based catalyst is designed with multi-functionality to simultaneously provide hydrodesulfurization, hydrodenitrogenation, and partial aromatic saturation activities. This reduces the need for multiple specialized catalysts, simplifying the overall system while maintaining high reaction specificity through the addition of the second catalyst only when needed
3Productivity
If higher metal content catalysts are used, then catalytic activity is improved, but catalyst cost and metal consumption increase
Solution Approach 1:
The second catalyst is designed with localized high metal content (particularly tungsten and phosphorus) specifically in the aromatic saturation zone, while the first catalyst uses lower metal content optimized for HDS and HDN. This local quality optimization ensures high catalytic activity where needed while minimizing overall metal consumption and cost
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 conversion rates of over 95% hydrodesulfurization, 90% hydrodenitrogenation, and 70-80% aromatics hydrogenation, with improved stability and reduced cycle time requirements, suitable for various hydrocarbon feedstocks including those with high sulfur, nitrogen, and aromatics content.
Implementation Method 1
a second catalyst with a nickel-molybdenum-tungsten-phosphorus active phase, with a specific volume distribution of 50-90%:10-50% for the first and second reaction sections, enhancing synergistic activity and stability for aromatics hydrogenation
Implementation Method 2
The process achieves high conversion rates of over 95% hydrodesulfurization
Implementation Method 3
90% hydrodenitrogenation
Data Source
AI summary
A subject matter of the invention is a process for the hydrotreating of a hydrocarbon feedstock having a distillation range of between 150° C. and 600° C., so as to obtain a hydrotreated effluent, said process comprising the following stages:a) said hydrocarbon feedstock is brought into contact, in the presence of hydrogen, with at least one first catalyst occupying a volume V1 and comprising a support based on alumina or silica or silica-alumina and an active phase consisting of nickel and molybdenum,b) the effluent obtained in stage a) is brought into contact, in the presence of hydrogen, with at least one second catalyst occupying a volume V2 and comprising a support based on alumina or silica or silica-alumina and an active phase consisting of nickel, molybdenum and tungsten, and phosphorus,the distribution of the volumes V1/V2 being of between 50% vol/50% vol and 90% vol/10% vol respectively.