Catalyst Feeding Process for Gas-Phase Polymerization Reactors
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Solution Overview
Problem
Existing methods for introducing catalyst powders into gas-phase olefin polymerization reactors face challenges such as catalyst degradation, plugging of feed lines, poor mixing with activators, and inefficient activation due to gaseous components entering the catalyst activation vessel, leading to non-uniform product formation and reduced catalytic efficiency.
Innovation Solution
A process involving storing Ziegler-Natta catalyst powder under a liquid alkane, metering it with a rotary valve, and transferring it to a catalyst activation section for contact with an organo-aluminum compound, followed by introduction into a gas-phase reactor, ensuring homogeneous distribution and optimal activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a compressed inert gas is used to deliver solid catalyst particles to the polymerization reactor, then the catalyst can be delivered without liquid suspension, but catalyst degradation and plugging of feed lines occur
Solution Approach 1:
The patent changes the physical state of the catalyst from dry solid particles to a slurry form by suspending catalyst particles in a liquid hydrocarbon carrier. This parameter change from gas-phase to liquid-phase delivery prevents catalyst degradation and feed line plugging while maintaining effective catalyst transport to the polymerization reactor.
Solution Approach 2:
The patent introduces a liquid hydrocarbon carrier as an intermediary medium to transport the catalyst particles. This liquid carrier protects the catalyst particles during transport, prevents direct contact with compressed inert gas that causes degradation, and ensures smooth flow through feed lines without plugging.
2Device complexity
If catalyst powder is stored under gaseous conditions, then storage is simplified, but gaseous components enter the activation vessel reducing catalytic efficiency
Solution Approach 1:
The patent changes the storage conditions from gaseous to liquid phase by maintaining the hydrocarbon carrier in liquid state. This liquid-phase storage prevents gaseous components from contaminating the activation vessel during catalyst transfer, thereby preserving catalytic efficiency while keeping the storage system relatively simple.
Solution Approach 2:
The patent uses an inert liquid hydrocarbon carrier environment for catalyst storage and transport. This inert liquid atmosphere prevents unwanted reactions and excludes gaseous components that would otherwise enter the activation vessel and reduce catalyst efficiency, while maintaining a straightforward storage configuration.
3Productivity
If catalyst particles are delivered in concentrated mass, then transport efficiency increases, but poor mixing with activators and non-uniform product formation occur
Solution Approach 1:
The patent uses a liquid hydrocarbon carrier as an intermediary medium that disperses catalyst particles during transport. This slurry form maintains high transport efficiency while ensuring uniform distribution of catalyst particles, which subsequently mixes properly with activators in the polymerization reactor to produce uniform product.
Solution Approach 2:
The patent creates a homogeneous slurry mixture of catalyst particles suspended in liquid hydrocarbon carrier. This homogeneous distribution prevents concentrated mass delivery issues, ensures uniform mixing with activators, and leads to consistent product formation throughout the polymerization process.
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 ensures high polymerization activity and morphological suitability of the catalyst, preventing gaseous components from entering the activation vessel and enhancing the efficiency of the catalyst activation step, resulting in improved product uniformity and catalytic performance.
Implementation Method 1
storing Ziegler-Natta catalyst powder under a liquid alkane
Implementation Method 2
metering it with a rotary valve, and transferring it to a catalyst activation section
Implementation Method 3
contacting the catalyst powder with a liquid phase comprising an organo-aluminum compound
Data Source
Figure 1
AI summary
A process for introducing a catalyst powder based on a titanium compound supported on magnesium halide into a gas-phase olefin polymerization reactor, characterized in that it comprises: (a) storing the catalyst powder under an atmosphere of a liquid C3-C12 alkane; (b) withdrawing from step (a) a measured amount of said catalyst powder by means of a rotary valve; (c) transferring said metered amount of catalyst powder to a catalyst activation section by a continuous pick-up flow of a liquid C3-C12 alkane; (d) contacting the catalyst powder with a liquid phase comprising an organo-aluminum compound and optionally an external donor compound, at a temperature ranging from -20 °C to 60 °C; (e) introducing the activated catalyst powder in one or more gas-phase olefin polymerization reactors, where a gaseous mixture comprising at least one alpha-olefin is subjected to polymerization.