Nickel Sorbent Purification for Metallocene Olefin Polymerization
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Solution Overview
Problem
Metallocene catalysts in olefin polymerization are sensitive to variations in hydrocarbon feedstocks, leading to irregular catalyst activities and unstable polymer properties, resulting in decreased productivity and increased production of off-specification resin, with existing stabilization methods being costly and inadequate.
Innovation Solution
A process involving a sorbent material with nickel deposited on a support, comprising both nickel oxide and metallic nickel, is used to purify the olefin-containing hydrocarbon feedstock, effectively removing impurities and stabilizing the polymerization conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metallocene catalysts are used for polymerisation, then product quality is improved, but catalyst activity becomes irregular due to sensitivity to feedstock variations
Solution Approach 1:
The patent applies preliminary action by treating the hydrocarbon feedstock with the nickel-based sorbent before polymerisation to remove impurities such as carbon monoxide, carbonyl sulphide, and acetylenic compounds. This pre-treatment stabilizes the feedstock quality, ensuring consistent catalyst activity throughout the polymerisation process and eliminating the need for continuous adjustments.
Solution Approach 2:
The nickel-based sorbent acts as an intermediary between the impure feedstock and the metallocene catalyst. It selectively removes harmful impurities while allowing the olefin to pass through, thereby protecting the catalyst from deactivation and maintaining stable polymerisation conditions without affecting the catalyst's ability to produce high-quality polymer.
2Reliability
If feedstock purification methods such as cryogenic distillation are used, then polymerisation stability is improved, but capital cost and operating expenses increase
Solution Approach 1:
The patent employs a cost-effective nickel-based sorbent that can be easily replaced when spent, rather than investing in expensive cryogenic distillation equipment. The sorbent provides sufficient purification for metallocene catalyst protection, and its low cost allows for periodic replacement without significant economic impact, achieving feedstock stabilization at a fraction of the cost of conventional methods.
Solution Approach 2:
The patent changes the purification approach from physical separation methods (cryogenic distillation) to chemical adsorption using nickel-based sorbent. This parameter change in the purification mechanism achieves effective removal of catalyst poisons at lower capital cost and operating expense, while maintaining polymerisation stability.
3Manufacturing precision
If continuous adjustments of reaction conditions are made to compensate for catalyst activity fluctuations, then polymer properties are maintained, but production of off-specification resin increases
Solution Approach 1:
By pre-treating the feedstock to remove impurities, the patent eliminates the need for continuous adjustments of reaction conditions. The stable feedstock quality ensures consistent catalyst activity, maintaining polymer properties throughout the run without producing off-specification resin, thereby maximizing productivity.
Solution Approach 2:
The patent eliminates the feedback loop of continuous monitoring and adjustment by providing upfront stabilization of feedstock quality. The nickel sorbent ensures consistent olefin purity, which translates to stable catalyst performance and consistent polymer properties without requiring real-time process adjustments.
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 enhances metallocene catalyst productivity and stability, reducing the need for continuous adjustments in reaction conditions and resulting in more consistent polymer properties, such as melt flow indices, while minimizing catalyst costs.
Implementation Method 1
passing an olefin-containing hydrocarbon feedstock over a sorbent material comprising nickel deposited on a support material wherein said nickel is present as both nickel oxide and metallic nickel
Data Source
AI summary
A process for the polymerisation of olefins comprising the steps of: a) passing an olefin-containing hydrocarbon feedstock over a sorbent material comprising nickel deposited on a support material wherein said nickel is present as both nickel oxide and metallic nickel; b) converting at least part of the olefins contained in said hydrocarbon feedstock into a polymer over one or more metallocene catalysts; and c) recovering the polymer product.