Offset Screen Configuration for Radial Flow Fluidization Control
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Solution Overview
Problem
In radial flow processes, the top of the solid particle bed is susceptible to fluidization due to horizontally moving fluid, leading to particle attrition, reduced efficiency, and increased pressure drop, which current methods fail to adequately address without excessive use of sealing portions of solid and fluid.
Innovation Solution
Offsetting the elevations of openings in upstream and downstream screens, combined with the use of sealing portions of both solid and fluid, directs fluid flow downward, reducing localized upward gas flow and fluidization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If screens with openings at the same elevation are used, then fluid flow is simplified, but particle fluidization occurs at the top of the bed
Solution Approach 1:
The patent applies asymmetry by offsetting the openings of the upstream screen relative to the downstream screen in the vertical direction. This asymmetric configuration prevents the horizontal fluid flow from directly acting on particles at the top of the bed, thereby eliminating fluidization while maintaining relatively simple screen structures.
Solution Approach 2:
The patent transitions from a two-dimensional alignment (openings at the same elevation) to a three-dimensional offset configuration. By introducing vertical displacement between screen openings, the fluid flow path is redirected downward through the particle bed, preventing upward flow that causes fluidization.
2Object-affected harmful factors
If sealing portions of solid and fluid are increased, then fluidization is reduced, but device complexity and material usage increase
Solution Approach 1:
The patent extracts the fluidization problem from its root cause by modifying the screen opening configuration. By removing the direct horizontal flow path at the top of the particle bed through vertical offset, the need for extensive sealing portions is eliminated, as fluidization is prevented by geometry rather than additional sealing materials.
Solution Approach 2:
The patent changes the vertical position parameter of screen openings relative to each other. This parameter change in the screen configuration fundamentally alters the fluid flow pattern, directing it downward through the particle bed and eliminating the conditions for fluidization without requiring increased sealing portions.
3Object-affected harmful factors
If offset screen configuration is used, then fluidization is reduced, but pressure drop across screens increases
Solution Approach 1:
The patent changes the vertical position parameter of screen openings to offset them relative to each other. This geometric parameter change redirects fluid flow downward through the particle bed, reducing fluidization. The pressure drop increase is an acceptable trade-off for eliminating particle fluidization and its harmful effects.
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 configuration minimizes fluidization, reduces pressure drop across the screens, and allows for efficient hydrocarbon conversion processes with reduced need for additional sealing portions, maintaining catalyst activity and process efficiency.
Implementation Method 1
Offsetting the elevations of openings in upstream and downstream screens, combined with the use of sealing portions of both solid and fluid, directs fluid flow downward, reducing localized upward gas flow and fluidization
Implementation Method 2
catalyst particles entering the top of a first reactor, moving downwardly as a compact column under gravity flow
Data Source
AI summary
Apparatuses and methods are disclosed for contacting radially flowing fluids with solid particles (e.g., catalyst) with reduced tendency for fluidization of the particles, and especially a sealing portion of the particles at the top of a particle retention zone disposed between screens at upstream and downstream positions relative to radial fluid flow. Fluidization is reduced or eliminated by offsetting openings of the screens in the axial direction, such that upstream openings in the upstream screen are above highest downstream openings in a downstream stream. The offset in openings imparts a downward flow component to radially flowing fluid, thereby reducing solid particle fluidization without the need to induce a specific pressure drop profile along the entire axial direction of the screens.