Oxygen Adsorbent Purification for Chromium Catalyst Protection

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Solution Overview

Problem

The process for preparing linear alpha olefins using chromium-based catalysts is hindered by oxygen impurities acting as catalyst poisons, leading to decreased conversion rates, product purity, and increased operating and separation costs due to by-products.

Innovation Solution

A method involving the removal of oxygen impurities from the feed olefin using an oxygen adsorbent, such as CuO, NiO, or zeolite 3A, followed by oligomerization with a chromium-based catalyst in a reactor, with the adsorbent being regenerated to maintain efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oxygen impurities are present in the feed ethylene, then the process can operate continuously, but the chromium-based catalyst is poisoned leading to decreased conversion rate and product purity

Engineering Contradiction:

Improvecatalyst activityVSAvoidoxygen impurity effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by introducing an oxygen removal unit before the oligomerization reactor. This unit uses oxygen adsorbents (such as copper-based, nickel-based, or zeolite materials) to remove oxygen impurities from the feed ethylene in advance, preventing catalyst poisoning before it occurs. The oxygen content is reduced to below 100 ppm, ensuring catalyst protection and maintaining high conversion rates and product purity throughout operation.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If oxygen removal is implemented, then catalyst activity and product purity improve, but process complexity and operating cost increase

Engineering Contradiction:

Improveconversion rateVSAvoidprocess structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent utilizes porous materials as oxygen adsorbents within the oxygen removal unit. Materials such as zeolites, activated alumina, or porous metal oxides provide high surface area for oxygen adsorption. These porous structures efficiently capture oxygen impurities while allowing ethylene to pass through, achieving effective purification without requiring complex multi-stage processing systems. The porous nature enables high capacity and selective adsorption, simplifying the overall process design.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent applies parameter changes by optimizing the oxygen adsorbent selection and operating conditions. Different adsorbent materials (copper-based, nickel-based, zeolite) are chosen based on their specific adsorption characteristics. Operating parameters such as temperature, pressure, and gas hourly space velocity are optimized to achieve maximum oxygen removal efficiency. The oxygen content is controlled to be below 100 ppm through these parameter optimizations, balancing purification effectiveness with process simplicity.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If oxygen adsorbent is used, then oxygen content is reduced to below 100 ppm, but additional equipment and regeneration processes are required

Engineering Contradiction:

Improveproduct purityVSAvoidprocess implementation

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent implements the discarding and recovering principle through the regeneration process of the oxygen adsorbent. After the adsorbent becomes saturated with oxygen impurities, it is regenerated by heating to desorb the accumulated oxygen, restoring its adsorption capacity. This allows the adsorbent to be reused multiple times, reducing the need for frequent replacement and minimizing waste. The regeneration unit enables continuous operation by cycling the adsorbent between adsorption and regeneration modes, maintaining high product purity while reducing long-term operational costs.

Inventive Principle:

Principle #34Discarding and recovering

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 approach enhances the process efficiency by reducing oxygen content to less than 100 ppm, improving the yield and purity of linear alpha olefins, and minimizing catalyst deactivation and process costs.

Implementation Method 1

removing oxygen impurities by contacting an olefin with an oxygen adsorbent

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

injecting the olefin from which the oxygen impurities are removed, and a chromium-based catalyst into a reactor; and oligomerizing the olefin in the reactor

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS11325874B2Method for preparing a linear alpha olefin including oxygen removal from the feed

Publication Date: 2022.05.10 SK INNOVATION CO LTD

AI summary

Provided is a method for preparing a linear alpha olefin using a chromium-based catalyst, including the steps of: removing oxygen impurities by contacting an olefin with an oxygen adsorbent; injecting the olefin from which the oxygen impurities are removed; a chromium-based catalyst into a reactor; and oligomerizing the olefin in the reactor.