PSA Dryer Dew Point Suppression via Polymer-Bound Desiccant
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Solution Overview
Problem
Existing compressed air drying systems, particularly desiccant dryers, face limitations in achieving specific dew point suppression and are prone to damage from excess moisture, leading to frequent servicing needs and reduced operational efficiency, especially in applications requiring small dew point adjustments and in environments like railway vehicles.
Innovation Solution
A pressure swing adsorption dryer using polymer-bound desiccant material, sized to produce a dew point suppression of less than 50°C, with desiccant members formed into tubes for controlled air flow and oriented horizontally, eliminating the need for heating and reducing dust formation, allowing for efficient and low-maintenance operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If desiccant dryers are used to achieve high dew point suppression, then drying performance is improved, but the desiccant material is damaged by excess moisture leading to frequent servicing
Solution Approach 1:
The patent implements dynamic control of the drying process by adjusting the flow rate of compressed air through the desiccant bed based on moisture content. The system transitions from static to dynamic operation, modifying the air flow rate in real-time to optimize water removal while preventing desiccant overload and damage, thereby extending operational continuity.
2Productivity
If desiccant dryers operate at high air flow rates, then productivity is improved, but drying performance deteriorates due to insufficient contact time
Solution Approach 1:
The system dynamically adjusts the air flow rate through the desiccant bed based on real-time moisture content measurements. When moisture levels are high, the flow rate is reduced to increase contact time and improve dew point suppression. When moisture levels are low, the flow rate is increased to maximize productivity. This dynamic adaptation resolves the contradiction between productivity and drying performance.
3Ease of operation
If refrigeration dryers are used for general purpose drying, then ease of operation is improved, but they cannot achieve dew points below freezing point
Solution Approach 1:
The patent changes the fundamental operating parameter from temperature-based drying (refrigeration) to adsorption-based drying (desiccant). This parameter change enables the system to achieve dew points below the freezing point without requiring sub-freezing temperatures, thereby maintaining ease of operation while expanding the achievable temperature range.
4Device complexity
If membrane dryers are used for small flows, then device complexity is reduced, but energy consumption increases due to significant pressure loss
Solution Approach 1:
The patent changes the operating parameters of the desiccant dryer to optimize the balance between pressure loss and drying performance. By adjusting the air flow rate through the desiccant bed and optimizing the bed configuration, the system achieves effective drying with minimal pressure loss, thereby reducing energy consumption while maintaining simplicity.
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 solution enables the use of desiccant dryers in applications requiring specific dew point adjustments, extends the life expectancy of desiccant materials, reduces the need for frequent servicing, and provides efficient dew point suppression, meeting ISO 8573.1 humidity quality classes 2 to 6, while being compact and easy to operate, even in challenging environments like railway vehicles.
Implementation Method 1
A pressure swing adsorption dryer using polymer-bound desiccant material, sized to produce a dew point suppression of less than 50°C
Implementation Method 2
Compressed air is fed to the first on-line column where water vapour is removed by the granular desiccant adsorption bed which is very efficient in adsorbing water vapour
Implementation Method 3
the desiccant material is bound together using a polymer binder and formed into desiccant members... the desiccant material, bound together using a polymer binder, is formed into desiccant members
Data Source
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AI summary
A method and apparatus for removing water from compressed air is disclosed. The method includes the steps of passing a stream of compressed air through a pressure swing adsorption (PSA) dryer. The dryer includes at least one vessel containing a desiccant material bound into pieces, for example tubes, using a polymer binder. The PSA dryer also has a control system for controlling the flow of the compressed air and switching between drying and purging modes. In particular the vessel and desiccant material contained therein are sized to produce a dew point suppression of less than 50°C.