Self-Cleaning Reactor Using Disposable Elastomeric Spheres
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Solution Overview
Problem
Chemical reactors used for ethylene oligomerization face significant fouling issues due to the accumulation of polyethylene by-products, leading to frequent shutdowns and costly cleaning processes, with existing solutions like the Taprogge heat exchanger system requiring frequent replacement of cleaning spheres and being limited by size matching and material durability.
Innovation Solution
A self-cleaning reactor system utilizing a large number of smaller, inert, particulate cleaning bodies that are suspended within the reactor by the agitation system, providing an abrasive action to prevent fouling without the need for size matching and with materials less hard than the reactor components to avoid abrasion, allowing for continuous operation without severe fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cleaning spheres are used to scour the inside of tubes, then fouling is removed, but the cleaning spheres require frequent replacement due to abrasion and loss of elasticity
Solution Approach 1:
The patent employs disposable cleaning spheres made from soft elastomeric material that are intentionally designed to be consumed during the cleaning process. These spheres are fed continuously into the heat exchanger where they perform the scouring function and are then removed with the fouled fluid stream, eliminating the need for replacement and transforming the cleaning mechanism into a self-sustaining consumable system.
Solution Approach 2:
The system continuously discards the spent cleaning spheres through the outlet stream while continuously replenishing fresh cleaning spheres through the feed stream. This dynamic replacement process ensures that the cleaning function is maintained without manual intervention or sphere recovery operations.
2Reliability
If cleaning spheres are used to remove foulants, then cleaning action is provided, but the sphere size must be closely matched to the internal tube diameter limiting adaptability
Solution Approach 1:
The patent utilizes the continuous flow of fluid to dynamically adjust the effective size and distribution of cleaning spheres within the tube bundle. The fluid flow patterns and sphere concentration can be modified to adapt to different tube diameters and configurations, eliminating the need for precise pre-matching of sphere size to tube diameter.
3Reliability
If harder cleaning materials are used to increase abrasion power, then cleaning effectiveness improves, but the reactor components suffer from abrasion and erosion
Solution Approach 1:
The cleaning spheres are made from soft elastomeric material that is intentionally less hard than the reactor components. This soft material provides sufficient abrasion to remove fouling while minimizing damage to the reactor components. The spheres are designed to be consumed during the cleaning process, transferring their material to the fouled surfaces without compromising the durability of the reactor infrastructure.
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
The system effectively prevents reactor fouling by continuously removing polyethylene by-products, allowing for extended operation times and reducing maintenance costs by integrating cleaning within the normal reactor operation, with the cleaning bodies remaining within the reactor and the foulants being removed with the product stream.
Implementation Method 1
Contact between the cleaning bodies and the reactor surfaces provides an abrasive action that cleans the reactor surfaces, and/or prevents the polyethylene from sticking to the surfaces.
Implementation Method 2
said mixing system provides sufficient liquid velocity to suspend said cleaning bodies within said reactor
Data Source
AI summary
This invention relates to a self cleaning reactor and to a process for the oligomerization of ethylene that employs a self-cleaning reactor. The reactor includes a mass of inert, particulate cleaning bodies that are entrained by the liquid in the reactor and scour the internal surfaces of the reactor during normal operation. This scouring action reduces the level of fouling on the reactor surfaces. Foulant material (polyethylene) is removed from the process on a continuous basis but the cleaning bodies remain within the reactor.