Selective Hydrogenation Catalyst for Olefin Streams
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Solution Overview
Problem
The separation of alkynes and dienes from olefin-containing hydrocarbons is challenging due to their high unsaturation, making it difficult to remove these impurities without also hydrogenating the desired olefin hydrocarbons, leading to inefficiencies and increased costs in existing hydrogenation processes.
Innovation Solution
A selective hydrogenation process using a catalyst with palladium and a Group IB metal, such as silver, supported on a low surface area inorganic oxide with a specific pore volume distribution, which allows for the selective hydrogenation of alkynes and dienes in olefin-containing hydrocarbon feeds, minimizing the conversion of desired olefins to paraffins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydrogenation catalysts are used to remove alkynes and dienes, then the impurities are hydrogenated, but the desired olefin hydrocarbons are also converted to paraffins
Solution Approach 1:
The patent modifies the catalyst's physical and chemical parameters, specifically using a low surface area inorganic oxide support (2-20 m²/g) with controlled pore volume distribution, and incorporates Group IB metals (Ag, Cu, Au) with Pd to alter the catalyst's selectivity characteristics, thereby achieving high alkyne/diene conversion while minimizing olefin hydrogenation
Solution Approach 2:
The patent creates a composite catalyst system combining Pd with Group IB metals (Ag, Cu, or Au) on an inorganic oxide support. This composite structure leverages the synergistic effects of different metals to enhance selectivity, where the Group IB metals modify the electronic and geometric properties of Pd sites to preferentially hydrogenate alkynes and dienes over olefins
2Manufacturing precision
If fractionation is used to separate alkynes from olefins, then separation is achieved, but the process becomes complex and costly
Solution Approach 1:
The patent develops a universal catalyst that can simultaneously handle multiple unsaturated impurities (acetylene, propadiene, methyl acetylene, butadiene, etc.) in a single reactor system, eliminating the need for multiple separate fractionation and hydrogenation units that would otherwise be required for each individual impurity stream
Solution Approach 2:
The patent extracts the separation function from the fractionation process by using a highly selective catalyst that can distinguish between alkynes/dienes and olefins based on their chemical reactivity, thereby removing the need for complex physical separation systems and replacing them with a single chemical transformation step
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
This process achieves high selectivity for the hydrogenation of alkynes and dienes, resulting in improved recovery of ethylene and reduced losses of propylene and ethylene, while maintaining the stability of the catalyst and system performance across varying conditions.
Implementation Method 1
contacting the hydrocarbon feed containing at least about 10,000 ppm by weight alkyne content and/or diene with a catalyst in a first reaction zone under selective hydrogenation conditions
Implementation Method 2
This gas typically contains substantial quantities of hydrogen as a result of the cracking step
Data Source
AI summary
A process for the selective hydrogenation of one or more alkyne and/or one or more diene in an olefin-containing hydrocarbon feed includes contacting the hydrocarbon feed with a catalyst under selective hydrogenation conditions, the catalyst including from about 0.01 to about 0.1 weight percent palladium and from about 0.005 to about 0.6 weight percent of at least one Group IB metal incorporated into an inorganic support, wherein the surface area of the support is from about 2 to about 20 m2/g, the pore volume is greater than about 0.4 cc/g, at least about 90% of the pore volume is contained in pores with pore diameters larger than about 500 Å, and the pore volume of the pores with a pore diameter from about 500 to about 1,000 Å comprise from about 1% to about 2% of the total pore volume.