Stage-Adjusted Catalyst Exchange in Olefin Oligomerization
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Solution Overview
Problem
The existing oligomerization processes for olefins face significant downtime and economic losses due to the gradual degradation and poisoning of catalysts, requiring frequent replacement across multiple reaction stages, which disrupts continuous operation and reduces conversion efficiency.
Innovation Solution
Implementing a process with a shorter catalyst replacement cycle in the first reaction stage compared to subsequent stages, using a catalyst composition of 15-40% NiO, 5-30% Al2O3, 55-80% SiO2, and 0.01-2.5% alkali metal oxide, and ensuring partial removal of nitrogen, oxygen, and sulfur impurities, allowing for more frequent refreshment of the first stage catalyst while maintaining longer cycles for downstream stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catalyst is replaced in all reaction stages at the same time after 48-72 months, then the catalyst activity is maintained across the entire plant, but the plant experiences long downtime and significant sales loss during the replacement period
Solution Approach 1:
The patent divides the catalyst replacement process into segments by reaction stage. The first reaction stage catalyst is replaced more frequently (every 47 months or less) than catalysts in subsequent stages (replaced every 48-72 months). This segmentation allows the plant to maintain continuous operation in downstream stages while performing replacement in the first stage, thereby reducing overall downtime and sales loss while still maintaining adequate catalyst activity across all stages.
2Productivity
If the catalyst replacement interval is extended to 48-72 months, then operational continuity is improved, but catalyst activity decreases due to aging and poisoning
Solution Approach 1:
The patent applies different replacement intervals to different reaction stages based on their specific requirements. The first reaction stage, which handles the feed mixture with highest impurity content, receives more frequent replacement (every 47 months or less) to maintain catalyst activity. Downstream stages experience less catalyst deactivation and can operate with longer replacement intervals (48-72 months), thereby maintaining operational continuity while ensuring each stage has appropriate catalyst activity.
3Reliability
If catalyst replacement is performed frequently to maintain high activity, then conversion efficiency is improved, but the frequency of plant shutdowns increases
Solution Approach 1:
By segmenting the replacement schedule across different reaction stages, the patent enables continuous operation in stages that are not currently undergoing replacement. The first stage is replaced more frequently but this does not require shutdown of the entire plant, as downstream stages continue operating. This segmentation resolves the contradiction by allowing frequent replacement where needed while maintaining continuous production elsewhere.
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 significantly shortens the period of catalyst replacement-related downtime, maintains higher activity levels, and reduces overall sales losses by allowing more efficient and continuous operation with lower overall catalyst exchange time.
Implementation Method 1
The oligomerization being carried out in at least two successive reaction stages using in each case an oligomerization catalyst having a composition of 15 to 40% by weight NiO, 5 to 30% by weight Al2O3, 55 to 80% by weight SiO2 and 0.01 to 2.5% by weight of an alkali metal oxide
Data Source
AI summary
The invention relates to a process of at least two stages for the oligomerization of short-chain olefins in the presence of a catalyst, wherein the regeneration of the catalyst is adapted to the stage.