Unperforated Cross-Passage Packing for Lower Pressure Drop
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Solution Overview
Problem
Existing cross-passage packings with perforations suffer from increased pressure drop and material loss, which negatively impact mass transfer efficiency, despite intended improvements in gas exchange and pressure drop reduction.
Innovation Solution
A cross-passage packing method using unperforated metal fabric layers with corrugated or pleated structures, where the angle between crossing passages is less than 100°, and liquid loading is maintained at a low level (L/a < 10 l/m²h), forming a self-wetting carrier for the liquid stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If perforations are added to metal fabric packings to improve gas exchange, then gas exchange is improved, but pressure drop increases and material surface is lost
Solution Approach 1:
The invention extracts the harmful element (perforations) from the system. By removing perforations from the metal fabric packing, the patent eliminates the source of pressure drop increase and material surface loss, while maintaining gas exchange functionality through the intact fabric structure and liquid film formation.
Solution Approach 2:
The invention changes the operational parameters, specifically maintaining liquid loading below 10 l/m²h. This parameter change enables the unperforated fabric to function effectively as a mass transfer surface without the need for perforations, thereby reducing pressure drop while maintaining gas exchange capability.
2Stress or pressure
If perforations are added to metal fabric packings to reduce pressure drop, then pressure drop is reduced, but material surface is lost and mass transfer efficiency decreases
Solution Approach 1:
The invention inverts the conventional approach by using unperforated fabric instead of perforated fabric. Counterintuitively, this reversal eliminates pressure drop while maintaining or improving mass transfer efficiency, as the intact fabric provides continuous liquid film formation and larger effective surface area.
Solution Approach 2:
By changing the liquid loading parameter to remain below 10 l/m²h, the invention enables the unperforated fabric to operate in an optimal regime where capillary wicking and liquid film formation provide efficient mass transfer without requiring perforations, thus maintaining productivity while reducing pressure drop.
3Stress or pressure
If unperforated metal fabric is used, then pressure drop is reduced, but liquid distribution may be insufficient
Solution Approach 1:
The unperforated metal fabric serves itself by utilizing capillary forces and surface tension to automatically distribute and retain the liquid film across its surface. This self-service mechanism eliminates the need for external liquid distribution systems or perforations, achieving both low pressure drop and adequate liquid distribution simultaneously.
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 approach results in a significantly smaller pressure drop and improved mass transfer characteristics, with the unperforated fabric packing demonstrating a 20% reduction in pressure loss compared to perforated designs, while maintaining equivalent separation efficiency.
Implementation Method 1
Since the metal fabrics form 'self-wetting' carriers of the liquid stream
Implementation Method 2
the metal fabric forms a carrier for the liquid stream which is unperforated, i.e. largely free of perforations or other openings
Implementation Method 3
The fabric packing is composed of vertical layers that consist of corrugated or pleated metal fabrics that form flow passages
Implementation Method 4
an exchange of material and/or heat is carried out between a liquid stream and a stream of gas or vapor
Implementation Method 5
which takes place at a phase interface between a descending liquid film on the packing surface and a gas stream flowing through the passages
Data Source
AI summary
The use of a cross-passage packing made of a metal fabric relates to a method in which an exchange of material and/or of heat is carried out between a liquid stream and a gas or vapour stream. The fabric packing (1) used is composed of vertical layers (11′, 12′) which consist of corrugated or pleated metal fabrics (11, 12) which form flow passages (13). The gas or vapour stream flows in the flow passages and the liquid stream flows on the metal fabric. The flow passages of adjacent layers cross in an open manner. The angle between crossing passages is lower than approximately 100°. In this method, the fabric packing is acted on by a relatively small liquid loading. The metal fabric forms a carrier for the liquid stream that is largely free of holes or other apertures. Values for the liquid loading are selected in accordance with the relationship L/a<10 l/mh, where L is the specific surface loading in volume units of the liquid per surface unit of the packing cross-section, and a is the specific surface which the metal fabric spans.