Thioresistant Catalyst for Pyrolysis Gasoline Selective Hydrogenation
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Solution Overview
Problem
Selective hydrogenation catalysts used in refining and petrochemistry face deactivation due to sulphur-containing impurities, leading to reduced performance and selectivity, and existing solutions either compromise hydrogenating activity or promote unwanted reactions.
Innovation Solution
A catalyst with an active phase comprising a noble metal from group VIIIB and 2% to 50% by weight of a metallic oxide from group IB or IIB, supported on refractory oxides or other materials, which reduces sulphur affinity and enhances selectivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogens are added to the active phase to improve resistance to sulphur-containing impurities, then sulphur resistance is improved, but hydrogenating activity is reduced and unwanted oligomerization reactions are promoted
Solution Approach 1:
The patent changes the chemical composition parameter by replacing halogen elements with metallic oxides from groups IB or IIB. This substitution maintains sulphur resistance while eliminating the negative effects on hydrogenating activity and oligomerization. The metallic oxides provide sulphur binding capability without creating surface acidity that promotes unwanted reactions.
Solution Approach 2:
The patent uses metallic oxides that can be easily incorporated into the catalyst structure and provide durable sulphur resistance without the need for halogen treatment or regeneration steps. The metallic oxide component acts as a sacrificial element that binds sulphur impurities, protecting the active metal phase.
2Reliability
If halogens are added to the active phase to improve resistance to sulphur-containing impurities, then sulphur resistance is improved, but unwanted oligomerization reactions are promoted due to increased surface acidity
Solution Approach 1:
The patent changes the chemical nature of the sulphur-resistant component from halogen (which creates acidic sites) to metallic oxide (which does not create significant surface acidity). This parameter change maintains sulphur resistance while eliminating the promotion of oligomerization reactions.
Solution Approach 2:
The patent converts the potential harm of sulphur-containing impurities into a benefit by using metallic oxide as a sulphur trap. The metallic oxide preferentially binds sulphur, protecting the active metal sites from deactivation while avoiding the creation of harmful acidic sites that would promote oligomerization.
3Stability of the object's composition
If selective hydrogenation is performed to eliminate polyunsaturated compounds, then product stability is improved, but catalyst deactivation occurs due to oligomer formation and sulphur contamination
Solution Approach 1:
The metallic oxide acts as an intermediary component that protects the active metal phase from deactivation. It serves as a buffer between the sulphur-containing feed and the active hydrogenation sites, binding sulphur impurities and preventing them from poisoning the catalyst, thereby extending catalyst service life.
Solution Approach 2:
The metallic oxide component provides beforehand cushioning by being positioned in the catalyst structure to intercept and bind sulphur impurities before they can reach and deactivate the active metal sites. This preventive mechanism extends catalyst durability.
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 extends its operational cycle, reduces unwanted reactions, and maintains high selectivity and activity even in the presence of sulphur-containing impurities, thereby increasing its service life and performance.
Implementation Method 1
reduces sulphur affinity
Implementation Method 2
selective hydrogenation of hydrocarbons comprising acetylenic, dienic and/or alkenylaromatic functions
Implementation Method 3
Acetylenic, diolefinic and alkenylaromatic compounds are highly reactive polyunsaturated compounds which polymerize very readily
Data Source
AI summary
The invention concerns a thioresistant catalyst which comprises an active phase deposited on a support, said active phase comprising at least one noble metal from group VIIIB and at least one metallic oxide from group IB or from group IIB, said support being selected from the group formed by refractory oxides, coal, clays, silica-alumina and/or their mixtures, and said support having a specific surface area in the range 110 to 300 m2/g. The invention also concerns the process for the preparation of said catalysts and their uses in the selective hydrogenation of hydrocarbons comprising acetylenic, dienic and/or alkenylaromatic functions. The invention is applicable to the refining field, and more particularly to the treatment of gasolines obtained by steam cracking (pyrolysis gasoline).