Segmented Cylindrical Wall for Radial Flow Reactor Stress Management
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Solution Overview
Problem
Existing cylindrical walls in radial flow catalytic reactors face mechanical stress issues due to thermal expansion, leading to potential catalyst leakage and necessitating reactor shutdowns for weld repair, which results in significant operational disruptions.
Innovation Solution
A cylindrical wall design featuring a perforated cylinder and a grid assembly with removable assembly means, such as threaded rods and flange elements, that reduces mechanical stress and allows for independent replacement of grid elements, ensuring secure catalyst confinement without the need for a longitudinal weld.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a longitudinal weld is used to secure the grid to the perforated plate, then the cylindrical wall structure is formed and catalyst retention is achieved, but mechanical stress from thermal expansion causes weld failure and catalyst leakage
Solution Approach 1:
The grid is divided into multiple separate grid elements (first grid element, second grid element, etc.) that are independently secured to the perforated plate through transverse weld lines. This segmentation eliminates the continuous longitudinal weld, distributing thermal stress across multiple discrete weld points rather than one continuous stress concentration zone.
Solution Approach 2:
The problematic longitudinal weld line is completely removed from the design. Instead of welding the entire grid continuously to the perforated plate, the invention extracts the welding function to only specific transverse locations where individual grid elements meet the plate, eliminating the source of thermal expansion stress while maintaining catalyst retention functionality.
2Reliability
If a longitudinal weld is used to secure the grid to the perforated plate, then catalyst confinement is achieved, but weld breakage requires reactor shutdown for repair
Solution Approach 1:
The grid structure is segmented into multiple independently weldable elements. If a weld fails, only the specific grid element associated with that weld needs to be addressed, not the entire grid system. This modular approach enables localized repair or replacement without requiring complete reactor shutdown and extensive disassembly.
Solution Approach 2:
The design allows for dynamic maintenance operations where individual grid elements can be selectively removed, repaired, or replaced based on their condition. This flexibility enables maintenance scheduling that minimizes reactor downtime, as repairs can be performed on a component-by-component basis rather than requiring complete system shutdown for weld repair.
3Strength
If a grid structure with longitudinal weld is used, then mechanical strength is provided, but thermal expansion causes tearing or shearing forces
Solution Approach 1:
By segmenting the grid into multiple elements with transverse weld lines, the structure maintains mechanical strength through distributed welding points while creating natural stress break points. Each grid element can expand and contract independently, preventing the accumulation of thermal stresses that would lead to tearing or shearing in a continuous welded structure.
Solution Approach 2:
The welding is applied locally at transverse positions where grid elements meet the perforated plate, rather than continuously along the entire length. This localized welding approach provides sufficient structural strength at critical connection points while allowing the grid elements to accommodate thermal expansion without generating excessive stresses along the entire structure.
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 design enhances the robustness and maintainability of the cylindrical wall, reducing the likelihood of reactor shutdowns and facilitating easier maintenance by allowing for the independent replacement of grid elements, thus minimizing the impact of thermal expansion-induced mechanical stresses.
Implementation Method 1
the weld may be subjected to relatively high mechanical stresses, in particular by thermal expansion during cases of unplanned shutdown of the unit or during restart phases
Implementation Method 2
a grid assembly, generally cylindrical in shape, intended to be in contact with the solid particles, the assembly of grid and the perforated cylinder being concentric, the grid assembly comprising at least one grid element, this element comprising a plurality of wires each extending in a longitudinal direction and arranged adjacent to each other in order to let the fluid circulate between the wires while filtering the solid particles
Data Source
Figure 1
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Figure 5A~6
AI summary
A cylindrical wall (100) for filtering solid particles in a fluid, through which this fluid is able to circulate, said wall comprising: a perforated cylinder (30) made from at least one perforated plate, a mesh assembly (110) in the general shape of a cylinder, intended to be in contact with the solid particles, the mesh assembly and the perforated cylinder being concentric, the mesh assembly comprising at least one mesh element (113), said mesh element comprising a plurality of wires (111), means of assembling the at least one mesh element so as to form the mesh assembly in the general shape of a cylinder, said means of assembly being arranged to attach the at least one removable mesh element on the perforated plate.