Thermal Cracking Tube Agitation Structure for Laminar Flow Suppression
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Solution Overview
Problem
Existing thermal cracking tubes suffer from inefficient heat transfer and laminar flow generation, leading to overheating and coking, which reduces the yield of olefin production and necessitates frequent decoking.
Innovation Solution
The thermal cracking tube is equipped with inwardly projecting fins and randomly shaped bumps on its inner surface to enhance agitation, preventing laminar flow and improving heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fins are formed on the inner surface of the tube to agitate the feedstock, then heat transfer efficiency is improved, but laminar flow is generated in regions where fins are not formed, leading to overheating
Solution Approach 1:
The patent applies local quality by providing bumps only in specific regions near the fins rather than uniformly across the entire inner surface. This localized modification creates turbulence precisely where needed (in the boundary film region) while maintaining the heat transfer enhancement benefits of the fins elsewhere.
Solution Approach 2:
The agitating element is segmented into two distinct components: fins that extend along the inner surface for general agitation and heat transfer enhancement, and bumps that are localized near the fins to specifically address laminar flow issues in the boundary film region. This segmentation allows each component to perform its specialized function.
2Productivity
If the feedstock is heated rapidly to reach reaction temperature, then thermal cracking efficiency is improved, but excessive heating causes lightening of hydrocarbons and coking
Solution Approach 1:
The patent modifies the flow regime parameter by introducing bumps that generate turbulence. This changes the flow from laminar to turbulent in critical regions, enhancing heat transfer uniformity and preventing localized overheating that leads to excessive cracking and coking.
3Reliability
If coking occurs on the inner surface of the tube, then heat transfer coefficient declines, but frequent decoking reduces operating hours
Solution Approach 1:
The bumps are positioned upstream and downstream of the fins to create turbulence that prevents coking before it can form on the tube surface. By maintaining turbulent flow in the boundary film region, the patent preemptively prevents the conditions that lead to coking, thereby maintaining heat transfer efficiency and extending operating hours between decoking operations.
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 enhanced agitation increases the yield of olefin production by preventing overheating and reducing coking, thereby extending the operational lifespan and efficiency of the cracking tube.
Implementation Method 1
the fluid material is heated rapidly, and the thermal cracking process is complete in a short period of time
Implementation Method 2
The fins serve to agitate the feedstock fluid material flowing at high speed to enhance the heat transfer of the tube
Data Source
AI summary
The present invention provides a thermal cracking tube having the effect of agitating a fluid in the tube and capable of preventing overheating due to the generation of laminar flow, wherein the thermal cracking tube 10 has an agitating element 20 formed on and projecting inwardly from an inner surface of the tube, wherein the fluid agitating element comprises a fin 21 extending along the inner surface of the tube and bumps 24 provided on a region near the fin and projecting inwardly from the inner surface of the tube, wherein the region near the fin includes an upstream side and/or a downstream side of the fin in the direction of the fluid flowing through the tube.