U-Shaped Heat Exchange Tube Flow Guide for Carbon Deposition Prevention
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Solution Overview
Problem
Fluidized bed reactors for silicone monomer synthesis face issues with carbon deposition due to flow dead zones and local overheating caused by changes in cross-sectional geometry and uneven gas distribution, leading to reduced selectivity and yield of dimethyldichlorosilane.
Innovation Solution
A device with U-shaped heat exchange tubes featuring upper and lower flow-guide blocks and a gas-solid flow active control device is used to alleviate particle accumulation and regulate gas-solid flow, eliminating flow dead zones and overheating by guiding particles and distributing gas effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a U-shaped heat exchange tube is used for internal heat exchange, then heat discharge is achieved, but geometric changes in cross-section and elbow portions cause flow dead zones and local overheating
Solution Approach 1:
The heat exchange tube is divided into multiple sections with different cross-sectional areas along its length. The tube includes a first section with a first cross-sectional area and a second section with a second cross-sectional area, creating segmented zones that prevent uniform flow patterns and eliminate dead zones while maintaining effective heat exchange throughout the fluidized bed reactor.
2Productivity
If gas injection tubes are arranged to improve gas distribution, then gas-solid flow is enhanced, but particle erosion on the tubes increases
Solution Approach 1:
The gas injection tubes are designed with varying injection angles and positions optimized for gas distribution. The tubes are arranged at specific angles relative to the reactor wall and positioned at different heights to create optimal gas-solid mixing while minimizing direct particle impact on the tube surfaces, thereby reducing erosion.
3Stability of the object's composition
If particle guide devices are added to eliminate sidewall accumulation, then particle distribution improves, but airflow and particle movement are hindered
Solution Approach 1:
Instead of using vertical particle guide devices that extend into the fluidized bed, the invention employs horizontal or radially oriented flow control structures at the sidewalls. These structures guide particles laterally and prevent accumulation at the walls without creating vertical obstructions that would hinder upward particle movement and airflow, thus maintaining fluidization efficiency while achieving uniform particle distribution.
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 solution completely eliminates flow dead zones and local overheating, improving the selectivity and yield of dimethyldichlorosilane by preventing carbon deposition and enhancing reactor efficiency and longevity.
Implementation Method 1
By means of the internal heat exchange component, the heat generated from the exothermic reaction is discharged in time to achieve a constant reaction temperature
Implementation Method 2
an upper flow-guide block is arranged on an upper surface of the elbow portion... a width of the upper flow-guide block decreases from an end connected to the elbow portion to an end away from the elbow portion
Implementation Method 3
dimethyldichlorosilane (M2), accounting for more than 90% of the total monomer yield, is mainly prepared from silica powder and chloromethane gas via a one-step reaction in a fluidized bed reactor
Data Source
AI summary
Disclosed are a method and device for preventing carbon deposition in a fluidized bed reactor for the organosilicon monomer synthesis. The device includes a tank, at least one U-shaped heat exchange tube, and at least one upper flow-guide block. The U-shaped heat exchange tube includes an elbow portion, and is arranged vertically with the elbow portion at a lower end. The upper flow-guide block is arranged on an upper surface of the elbow portion. A width of the upper flow-guide block decreases from an end connected to the elbow portion to an end away from the elbow portion.