Transverse Cooling Coil Arrangement for Oxidation Reactor Heat Transfer
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Solution Overview
Problem
Conventional acrylonitrile reactor cooling coil designs face inefficiencies due to poor heat transfer, mechanical stress, and corrosion, leading to reduced reactor performance, increased downtime, and high maintenance costs.
Innovation Solution
The cooling coil assembly is redesigned with closely packed, transversely arranged cooling coil courses, adjusted flow passageway cross-sectional areas to minimize steam conversion, and the use of thermal sleeves to mitigate thermal stress, along with relocating the cooling water outlet header to reduce flowback and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cooling coil designs are used with co-planar coil courses, then the structure is simple and easy to manufacture, but heat transfer efficiency is poor and cooling capacity is insufficient
Solution Approach 1:
The patent transitions from co-planar cooling coil courses to a three-dimensional configuration where coil courses are arranged in multiple planes with transverse orientations. This spatial arrangement increases the heat transfer surface area within the same reactor volume and improves thermal contact with the catalyst bed, thereby enhancing cooling capacity while maintaining manufacturing feasibility through standard coil assembly techniques.
2Ease of manufacture
If cooling coil outlet header is positioned at conventional elevation, then installation is straightforward, but cooling water flowback occurs causing erosion and reduced reliability
Solution Approach 1:
The patent inverts the conventional approach by positioning the cooling water outlet header at a lower elevation than the cooling coil outlets. This gravitational arrangement prevents flowback of cooling water into the coils, eliminating erosion at the coil-outlet connections and extending service life. The inverted configuration is achieved through standard piping practices and does not complicate installation.
3Device complexity
If cooling water passageway cross-sectional area is not optimized, then design is simple, but excessive steam conversion occurs causing mechanical stress and thermal damage
Solution Approach 1:
The patent optimizes the cross-sectional area of cooling water passageways to control steam conversion to approximately 15% or less. This parameter adjustment balances heat transfer efficiency with mechanical stress management. The passageway dimensions are calculated based on heat load requirements and are implemented through standard pipe sizing and design practices without excessive complexity.
4Ease of operation
If cooling coil courses are spaced far apart, then installation and maintenance access is easier, but heat transfer efficiency decreases and cooling performance is insufficient
Solution Approach 1:
The patent employs a three-dimensional arrangement of cooling coil courses in multiple planes with transverse orientations. This configuration achieves close spacing between coils for optimal heat transfer while maintaining adequate clearance in different spatial directions for maintenance access. The multi-plane arrangement allows maintenance personnel to access coils from multiple vantage points, balancing thermal performance with operational requirements.
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 cooling capacity, reduces mechanical stress, and extends the life of cooling coils, improving reactor performance and reducing maintenance and repair costs.
Implementation Method 1
cooling coil assembly to withdraw excess heat and thereby keep the reaction temperature at an appropriate level
Implementation Method 2
cooling water passageway for transport of cooling water therethrough
Data Source
Figure 1
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Figure 4~5
AI summary
The cooling coils used in a commercial oxidation or ammoxidation reactors can be made more closely packed by providing the individual courses defining the cooling coil in a transverse arrangement rather than a linear alignment.