Nickel-Based Catalyst for Pyrolysis Gasoline Hydrogenation
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Solution Overview
Problem
Current nickel-based catalysts for the selective hydrogenation of pyrolysis gasoline suffer from inferior performance due to variability in raw materials and increased impurity content, particularly arsenic, which affects their stability and resistance to hydrogenation loads.
Innovation Solution
A nickel-based Al2O3 supported catalyst with specific compositions and preparation methods, including 14-20% nickel oxide, 1-8% lanthanum or cerium oxide, 1-8% VIB group element oxide, 2-8% silica, and 1-8% alkaline earth metal oxide, providing improved hydrogenation activity, selectivity, and stability, especially in the first-stage hydrogenation of full distillate pyrolysis gasoline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If palladium-based catalyst is used for first-stage hydrogenation, then hydrogenation activity is improved, but arsenic resistance and stability deteriorate due to impurity arsenic occupying the empty orbital of Pd
Solution Approach 1:
The patent replaces expensive noble metal catalysts (palladium) with non-noble metal nickel-based catalysts. While nickel catalysts have shorter operational life under severe impurity conditions, they provide cost-effective hydrogenation activity for full distillate pyrolysis gasoline, accepting reduced longevity in exchange for economic viability and sufficient performance
Solution Approach 2:
The patent employs a composite catalyst structure with nickel as the active component supported on alumina carrier, enhanced with promoters such as zinc oxide, calcium oxide, and magnesium oxide. This composite formulation improves arsenic resistance and stability while maintaining hydrogenation activity, resolving the contradiction between activity and reliability
2Ease of manufacture
If non-noble metal catalyst is used, then price advantage and certain arsenic tolerance are achieved, but hydrogenation activity and selectivity are reduced
Solution Approach 1:
The patent optimizes multiple parameters including nickel content (10-30% of total catalyst weight), carrier surface area (200-400 m²/g), pore volume (0.3-0.5 ml/g), and promoter ratios to maximize hydrogenation activity. By carefully adjusting these parameters, the nickel-based catalyst achieves activity levels comparable to or exceeding noble metal catalysts while maintaining cost advantages
Solution Approach 2:
The patent creates localized active sites on the alumina carrier surface through controlled nickel deposition and promoter distribution. The heterogeneous structure with nickel particles dispersed on the carrier provides high local activity zones that compensate for the inherently lower activity of non-noble metals, achieving high overall hydrogenation performance
3Ease of manufacture
If conventional nickel-based catalyst is used for full distillate hydrogenation, then cost is reduced, but hydrogenation stability and lifetime are insufficient due to increased impurity content and hydrogenation load
Solution Approach 1:
The patent performs preliminary stabilization of the nickel catalyst through controlled reduction and conditioning procedures before actual hydrogenation operation. The catalyst is pre-treated under controlled conditions to develop optimal surface properties and deactivate potential instability factors, thereby extending operational lifetime and improving stability under severe impurity conditions
Solution Approach 2:
The patent incorporates protective promoters (zinc oxide, calcium oxide, magnesium oxide) that act as buffers against impurity poisoning and thermal degradation. These promoters provide beforehand protection by preferentially interacting with harmful impurities and stabilizing the nickel active sites, cushioning the catalyst against deactivation and extending its operational lifetime
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 enhanced hydrogenation performance, stability, and resistance to impurities and colloids, prolonging its lifespan and maintaining effective hydrogenation activity over extended periods.
Implementation Method 1
selective hydrogenation of medium or low distillate oil, in particular, in the first-stage selective hydrogenation process of pyrolysis gasoline
Data Source
AI summary
A selective nickel-based hydrogenation catalyst and the preparation thereof, characterized in that: provided that the catalyst is weighed 100%, it comprises nickel oxide 14-20% as active component, lanthanum oxide and/or cerium oxide 2-8%, and VIB element oxide 1-8% as aids, 2-8% silica, 1-8% alkaline earth metal oxides, and alumina as the balance. The catalyst specific surface area is 60-150 m2/g, and the pore volume is 0.4-0.6 ml/g. The catalyst has good hydrogenation performance, especially impurity and colloid resistance and hydrogenation stability. The catalyst can be applied to the diolefin selective hydrogenation of medium or low-distillate oil, especially of the full-distillates pyrolysis gasoline.