Tube Bundle Ferrule Sealing for Corrosion Resistance
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Solution Overview
Problem
In vertical falling liquid film heat exchangers, especially those handling highly aggressive fluids like in urea synthesis processes, existing solutions fail to prevent corrosion and erosion effectively due to infiltration issues at the ferrule-tube interface, leading to deformation and non-uniform liquid distribution.
Innovation Solution
A tube bundle equipment design featuring a ferrule with a lateral metallic strip and annular gasket arrangement, ensuring secure sealing and uniform liquid distribution without the need for welding, using corrosion-resistant materials like zirconium and titanium, and avoiding removal of internal layers for ferrule insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ferrule designs are used in vertical falling liquid film heat exchangers handling aggressive fluids, then the equipment can operate under high pressure and temperature conditions, but corrosion and erosion occur due to infiltration at the ferrule-tube interface
Solution Approach 1:
A sealing element is introduced as an intermediary component between the ferrule and the tube to prevent infiltration of aggressive fluids. This sealing element acts as a mediator that blocks the harmful infiltration path while allowing the ferrule to remain securely connected to the tube, thereby preventing corrosion and erosion without compromising the high-pressure operation capability.
Solution Approach 2:
The sealing element is positioned specifically at the critical infiltration zone where the ferrule meets the tube. This localized sealing approach targets the exact area where harmful infiltration occurs, providing corrosion protection precisely where needed without requiring changes to the entire ferrule or tube structure.
2Ease of manufacture
If the internal layer of the tube is removed for ferrule insertion, then the ferrule can be installed to distribute liquid film, but erosion resistance is reduced at the insertion point
Solution Approach 1:
The sealing element is pre-installed onto the tube before the ferrule is attached. This preliminary action creates a protective barrier at the insertion point, allowing the ferrule to be installed without removing the tube's internal protective layer, thereby maintaining erosion resistance while enabling easy ferrule installation.
Solution Approach 2:
The sealing element serves as an intermediary that facilitates ferrule installation without requiring damage to the tube's protective internal layer. It provides a interface between the ferrule and tube that allows secure connection while preserving the tube's erosion-resistant surface integrity.
3Productivity
If non-uniform liquid distribution occurs in the tube, then heat exchange efficiency decreases, but preventing this requires complex distribution mechanisms
Solution Approach 1:
The ferrule is designed to perform multiple functions: it distributes the liquid film uniformly along the tube, provides a sealing function to prevent infiltration, and secures the connection between components. By combining these functions in a single element, uniform liquid distribution is achieved without adding complex separate distribution mechanisms.
Solution Approach 2:
The ferrule incorporates multiple radial openings distributed around its circumference, which segment the liquid flow into multiple streams that spread evenly along the tube surface. This segmentation approach achieves uniform liquid distribution through a simple geometric feature rather than a complex mechanism.
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 significantly prolongs the equipment's lifespan by preventing infiltration and ensuring uniform liquid distribution, reducing erosion and corrosion risks, and maintaining structural integrity under high-pressure and temperature conditions.
Implementation Method 1
the tubes are positioned vertically so that a uniform and thin liquid film flows by gravity from above along the wall
Implementation Method 2
suitable for effecting heat exchange between two fluids, one of which, in the liquid state, falls along the internal walls of the tubes in the form of a film
Implementation Method 3
Tube bundle equipment with liquid flow regulator elements comprising metallic regulator elements of the liquid flow
Data Source
AI summary
Tube-bundle equipment of the falling liquid film type, comprising a vertical cylindrical body closed at the ends and divided into at least an upper section, an intermediate section and a lower section by means of two perforated tube sheets arranged transversally to support the tubes forming the bundle, wherein each of said tubes is surmounted, on the upper end, by a ferrule, for the inlet and distribution of the liquid in the form of a film, which comprises in the upper part, one or more openings for the outlet of vapors, at an intermediate height one or more openings, preferably tangential, for the inlet of the liquid and below, a circular base for resting on said tube from which an internal cylindrical section, inserted in the tube for a length varying from 10 to 200 mm, protrudes downwards together with an outer metallic strip for a length of at least 2 mm, so that, in the circular area defined between said outer metallic strip and said protruding cylindrical section, there is a gasket, inserted between said circular base of the ferrule and said upper edge of the tube.