Variable Switching PSA Drying for Hydrogen Compressor Streams
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Solution Overview
Problem
Conventional methods for drying hydrogen streams from electrochemical hydrogen compressors (EHCs) using PSA devices face inefficiencies due to constant switching times, leading to unnecessary rapid switching and increased wear on components, especially when the mass flow rate of gas components is not constant.
Innovation Solution
A method to optimize the feeding and regeneration cycles of PSA devices by determining the mass flow rate of water in the hydrogen gas mixture and adjusting the adsorbent bed switching times based on the EHC's operating parameters, such as stack current, temperature, and pressure, to ensure efficient water adsorption and desorption, thereby reducing the size of adsorbent beds and enhancing PSA device efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant switching times are used in PSA devices, then the device structure is simple, but component wear increases and efficiency decreases due to unnecessary rapid switching
Solution Approach 1:
The patent applies dynamics by transitioning from fixed constant switching times to variable switching times that adapt to changing mass flow rates. The switching time is dynamically adjusted based on real-time detection of mass flow rate, allowing the PSA device to optimize its operation under varying conditions and reduce unnecessary rapid switching that causes component wear.
Solution Approach 2:
The patent implements feedback by detecting the mass flow rate and using this information to adjust the switching time. The control system continuously monitors the mass flow rate and modifies the switching time accordingly, creating a closed-loop control mechanism that optimizes device performance while reducing component wear from excessive switching.
2Productivity
If constant switching times are used in PSA devices, then the control system is simple, but productivity decreases due to inefficient adsorption cycles
Solution Approach 1:
The patent applies dynamics by making the switching time variable rather than constant. The switching time is dynamically adapted to match the actual mass flow rate conditions, ensuring that adsorption cycles are optimized for current operating conditions. This dynamic adjustment improves drying efficiency by preventing both premature switching (which reduces productivity) and unnecessarily prolonged switching (which wastes time).
Solution Approach 2:
The patent changes the parameter of switching time from a fixed constant to a variable parameter that depends on mass flow rate. By adjusting this critical parameter based on actual operating conditions, the system optimizes the adsorption cycle efficiency and improves overall productivity of the drying process.
3Quantity of substance
If fixed adsorption time is used, then the operation is straightforward, but adsorbent capacity is not optimized leading to larger bed sizes
Solution Approach 1:
The patent uses feedback by detecting the mass flow rate and adjusting the adsorption time accordingly. This allows the system to optimize adsorbent capacity utilization by matching the adsorption time to the actual amount of substance being processed, preventing both under-utilization (which would require larger beds) and over-utilization (which would reduce ease of operation).
Solution Approach 2:
The patent changes the adsorption time parameter from a fixed value to a variable that adapts to mass flow rate conditions. This parameter adjustment optimizes the utilization of adsorbent capacity, allowing smaller bed sizes to achieve the same drying effectiveness that would require larger beds under fixed-time operation.
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 optimizes the PSA device's efficiency by adjusting switching times according to the mass flow rate and adsorbent capacity, reducing wear on components and improving the overall performance by ensuring that adsorbent beds operate within their optimal capacity, thus enhancing the drying process of hydrogen streams.
Implementation Method 1
Elevating the partial pressures of the impurities may cause the impurities to adsorb onto adsorbent materials within the adsorbent bed
Implementation Method 2
PSA devices may separate gas fractions from gas mixtures by coordinating pressure cycling and flow reversal over an adsorbent material in an adsorbent bed
Implementation Method 3
Hydrogen gas in contact the anode may be oxidized by applying a voltage potential across the electrodes. Oxidation of a hydrogen molecule produces two electrons and two protons
Implementation Method 4
The transfer of charge or current within the cell is commonly referred to as the stack current
Implementation Method 5
The two protons are electrochemically driven through the membrane to the cathode, wherein the protons rejoin the two rerouted electrons and reduce back to a hydrogen molecule
Data Source
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AI summary
In accordance with one embodiment, a method of drying a hydrogen gas mixture is disclosed. The method may include determining a mass flow rate of water mH2O in a hydrogen gas mixture stream and an adsorbent capacity of one or more adsorbent beds; determining a first period of time based on the determined mass flow rate of water mH2O in the hydrogen gas mixture stream and the adsorbent capacity; directing the hydrogen gas mixture stream through a first adsorbent bed of the one or more adsorbent beds for the first period of time; adsorbing a quantity of water from the hydrogen gas mixture stream into the first adsorbent bed; and regenerating the first adsorbent bed.