Fines Ejector Clogging Prevention via Liquid Injection
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Solution Overview
Problem
Fouling and clogging issues in fines ejectors used in gas-phase olefin polymerization processes lead to frequent shutdowns, excessive cleaning expenses, and reduced efficiency due to polymer build-up, affecting both horizontally and vertically oriented designs.
Innovation Solution
Introducing a liquid stream into the motive gas stream before it enters the fines ejector to prevent or reduce clogging, using inert diluents or fresh α-olefins like propylene, 1-butene, and 1-hexene, which can be injected continuously or intermittently, to maintain flow and prevent fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a horizontal fines ejector is used to convey polymer particles, then the ejector can effectively return fines to the reactor, but polymer build-up occurs in the ejector causing fouling and clogging
Solution Approach 1:
The patent introduces a liquid stream (water or process liquid) as an intermediary substance injected into the motive gas stream. This liquid mediator prevents polymer particles from adhering to the ejector walls by creating a slippery surface, thereby eliminating fouling while maintaining the ejector's ability to convey fines back to the reactor
2Object-affected harmful factors
If a vertical fines ejector is used to reduce fouling, then some polymer build-up is ameliorated, but the ejector remains susceptible to periodic clogging
Solution Approach 1:
The liquid stream injection serves as a preventive intermediary that addresses the remaining clogging susceptibility in vertical ejectors. By continuously or periodically injecting liquid into the motive gas stream, the system maintains reliable operation and prevents periodic clogging events
3Reliability
If frequent cleaning of the ejector is performed to remove polymer build-up, then ejector performance is maintained, but plant shutdowns increase and production is lost
Solution Approach 1:
The liquid stream injection performs preliminary protective action by preventing polymer adhesion before it can cause significant build-up. This proactive approach eliminates the need for frequent cleaning shutdowns and maintains both ejector performance and plant productivity
Solution Approach 2:
The injected liquid stream acts as a protective intermediary layer on the ejector walls, preventing polymer particles from adhering and accumulating. This eliminates the need for shutdown cleaning operations while maintaining ejector performance
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
Significantly reduces clogging and fouling in fines ejectors, allowing for extended operation without shutdowns and maintaining consistent motive gas flow rates, as demonstrated in Example 1 where liquid hexene injection maintained flow until a planned annual shutdown.
Implementation Method 1
introducing a liquid stream into the motive gas stream before the motive gas stream enters the fines ejector
Data Source
Figure 1
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AI summary
A method for preventing or reducing clogging of a fines ejector in a gas-phase olefin polymerization process is disclosed. The process involves injecting a liquid into the motive gas stream entering the fines ejector.