Movable Basket Catalyst Storage for Reactor Stress Reduction
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Solution Overview
Problem
Industrial catalytic reforming units with multiple moving bed reactors in series face issues due to thermal expansion, leading to mechanical stress on reactor walls during catalyst stoppage and restart, potentially causing damage and economic losses.
Innovation Solution
A vertically movable basket with flaps and a deflector is integrated into the reactor to transfer catalyst to a temporary storage zone during stoppages, allowing for efficient reinsertion into the catalytic bed upon restart, facilitated by a deflector that aids in emptying the storage zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temporary catalyst storage zone is introduced to cope with circulation interruptions, then catalyst can be stored during stoppage, but the device complexity increases due to additional flaps and deflector mechanisms
Solution Approach 1:
The reactor internal structure is segmented into distinct functional zones: a catalytic bed zone for reaction, a temporary storage zone for catalyst accumulation during stoppages, and circulation legs for catalyst movement. This segmentation allows independent optimization of each zone's function while managing overall system complexity through modular design
Solution Approach 2:
The flap mechanism is designed to be dynamically adjustable, capable of rotating between different angular positions to control catalyst flow. The deflector is positioned to actively redirect catalyst flow patterns. These dynamic elements enable the system to adapt to varying operational conditions (normal circulation vs. stoppage) without requiring complete structural redesign
2Temperature
If the reactor walls are allowed to expand freely due to thermal expansion at operating temperatures, then the reactor can withstand high temperatures, but mechanical stress increases on the walls during cooling phase when catalyst accumulates
Solution Approach 1:
The temporary storage zone is pre-configured with flaps and deflectors positioned to facilitate catalyst accumulation before cooling occurs. When stoppage is detected or anticipated, the system can immediately direct catalyst into the storage zone, preventing sudden accumulation during cooling and the associated mechanical stress on reactor walls
Solution Approach 2:
The temporary storage zone acts as an intermediary buffer between the catalytic bed and the reactor walls during cooling phases. By providing a designated accumulation space with controlled geometry (flaps and deflectors), it mediates the transition of catalyst from active circulation to stored state, reducing direct impact stress on the reactor wall structure
3Reliability
If flaps are installed to release storage space during stoppage, then catalyst can be stored, but the ease of operation decreases due to complex flap movement mechanisms
Solution Approach 1:
The flap mechanism is designed to operate automatically in response to catalyst flow conditions. During normal circulation, catalyst flow itself helps maintain flaps in the open position. During stoppage, the absence of flow allows flaps to close automatically, directing catalyst into the storage zone without requiring external control signals or complex actuation systems
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 solution reduces mechanical stress on reactor walls, prevents damage, and ensures smooth catalyst recirculation, thereby minimizing economic losses and operational disruptions.
Implementation Method 1
the catalytic bed, composed of small porous alumina balls, circulates continuously through the reactors in the moving bed state according to a slow gravity flow
Implementation Method 2
the catalytic reforming process requires operating temperatures around 500°C. These high temperatures cause the walls of the steel reactor to expand
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 3
AI summary
The present invention describes a device allowing, on the one hand, the temporary storage of a certain quantity of catalyst and, on the other hand, the recirculation of said quantity in regenerative reforming units following an interruption in the circulation of the catalyst.