Plate Heat Exchanger Liquid Distribution Without Dry Vaporization
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Solution Overview
Problem
In air distillation installations, the existing heat exchangers with partially offset waves and horizontal generators suffer from non-uniform liquid distribution due to free spaces and clearances, leading to dry vaporization and deposit formation, which poses safety risks and efficiency issues.
Innovation Solution
The heat exchanger design incorporates side bars with a curved profile and cutouts to eliminate free spaces, ensuring uniform liquid distribution across channels by using overlapping waves with perfect edge contact and secure attachment, preventing liquid leaks and ensuring consistent flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If partially offset waves with horizontal generators are used in the heat exchanger, then compact structure and large exchange surface are achieved, but non-uniform liquid distribution occurs leading to dry vaporization and deposit formation
Solution Approach 1:
The wave structure is modified to have different profiles in different zones: the upper part maintains the partially offset configuration for compactness, while the lower part features a flat bottom section that extends across the entire passage width. This local modification ensures uniform liquid distribution at the critical vaporization zone without sacrificing the overall compact structure.
Solution Approach 2:
The wave is divided into two distinct segments: an upper partially offset section and a lower flat-bottom section. This segmentation allows each part to fulfill different functions - the upper part contributes to compactness while the lower part ensures uniform liquid distribution across all channels.
2Strength
If side bars with curved profiles are used to close passages, then structural integrity is maintained, but free spaces and clearances are created causing liquid undersupply in peripheral channels
Solution Approach 1:
The side bars are designed with a dual-profile structure: the upper part maintains the curved profile for structural strength, while the lower part features a flat profile that contacts the wave to eliminate clearances. This local modification precisely addresses the liquid distribution problem without compromising overall structural integrity.
Solution Approach 2:
The side bar profile is segmented into two zones: a curved upper section providing structural support and a flat lower section ensuring tight contact with the wave to eliminate free spaces and prevent liquid leakage.
3Area of stationary object
If multiple wave bands are placed side by side to cover passage width, then complete coverage is achieved, but clearances at junctions between wave mats cause liquid oversupply in some channels and undersupply in others
Solution Approach 1:
Multiple wave bands are merged by placing them in abutment against each other, with their flat bottom sections forming a continuous surface. The side bars with flat lower profiles ensure tight contact between adjacent waves, eliminating junction clearances and preventing liquid leakage that would cause non-uniform 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
This design enhances liquid distribution uniformity, reducing the risk of deposit formation and improving operational efficiency by ensuring consistent wetting of all channels, thereby minimizing the risk of explosions and optimizing the vaporization process.
Implementation Method 1
the liquid oxygen which is in the bottom of the low-pressure column is vaporized by heat exchange with the gaseous nitrogen taken from the top of the medium-pressure column
Implementation Method 2
aluminum exchangers with brazed plates and fins, which make it possible to obtain very compact components offering a large exchange surface
Implementation Method 3
the liquid oxygen then passes through a row of holes which provide its primary distribution to the vaporization passages. It then flows through a band of waves with a horizontal generator
Implementation Method 4
One of the important parameters for the formation of deposits is the flow of liquid per channel (or expressed per meter of perimeter to be wetted). Indeed, when the flow of liquid per channel is insufficient to wet the wall, there is formation of deposits by dry vaporization
Implementation Method 5
The quality of this liquid distribution depends on good design and sizing of the distributor. The so-called secondary distribution (distribution of the liquid between channels) uses a waveband with a horizontal generator and partial offset
Data Source
Figure 1A~2
Figure 3A~4B
Figure 5~7
AI summary
The invention relates to a heat exchanger (2) for vaporising a liquid by exchanging heat with a second fluid, including a parallelepiped body made up of an assembly of parallel vertical plates (4) defining a multitude of flat passages (17, 18) therebetween and lateral bars (7) closing the passages to the outside, a means for sending the liquid into a first assembly of passages (17) and the second fluid into the remaining passages (18), an insert (1, 3) for distributing the liquid at the top end of the passages (17) of said first assembly, across the entire horizontal length thereof, by fine distribution along the entire length of said passages, at least one of the lateral bars having a rounded profile along most of the length thereof and a flat profile on a portion of the length thereof, and one edge of the insert engaging the portion of the length of said bar where the profile is flat.