PSA Hydrogen Recovery via Vacuum Tank Off-Gas Management
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Solution Overview
Problem
In hydrogen production by pressure swing adsorption, there is a risk that the off-gas cannot be appropriately supplied to the combustion device due to inefficient suctioning methods, which affects the recovery efficiency of the adsorption target component and stability of the combustion process.
Innovation Solution
A method involving four adsorption columns with a vacuum pump that can switch between suctioning the adsorption column and a vacuum tank, allowing for controlled suction and communication states to ensure proper off-gas supply to the combustion device, while also using a vacuum tank with an off-gas adsorbent to manage pressure and capacity effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vacuum pump is used to suction the adsorption column in the desorption step to accurately release the adsorption target component, then the recovery efficiency of the adsorption target component is improved, but the off-gas cannot be appropriately supplied to the combustion device
Solution Approach 1:
The desorption step is divided into multiple phases: initial pressure reduction phase, intermediate vacuum suction phase, and final pressure equalization phase. This segmentation allows the system to achieve both high recovery efficiency during vacuum suction and stable off-gas supply during other phases by coordinating multiple adsorption columns at different stages of the cycle.
Solution Approach 2:
The off-gas tank is pre-filled with off-gas from previous cycles before the vacuum pump starts suctioning the adsorption column. This preliminary action ensures that the combustion device continues to receive adequate off-gas supply even when the vacuum pump is actively removing gas from the adsorption column, thus maintaining combustion stability while achieving high recovery efficiency.
2Reliability
If the off-gas tank capacity is increased to ensure continuous off-gas supply to the combustion device, then the off-gas supply stability is improved, but the equipment cost and complexity increase
Solution Approach 1:
Multiple adsorption columns operate in different stages of the PSA cycle simultaneously, ensuring that at least one column is always in the desorption or pressure-equalization phase, continuously supplying off-gas to the off-gas tank. This continuous action eliminates the need for large tank capacities to bridge supply gaps, reducing equipment complexity while maintaining supply stability.
Solution Approach 2:
The system recovers and stores off-gas in the off-gas tank during phases when it is available (desorption and pressure-equalization steps), then utilizes this stored off-gas during phases when production is low. This recovery and reuse approach optimizes the use of available off-gas, reducing the need for oversized storage capacity while ensuring continuous supply to the combustion device.
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 method enhances the recovery efficiency of the adsorption target component and stabilizes the combustion process by ensuring consistent off-gas supply and optimizing tank capacities, reducing equipment costs and complexity.
Implementation Method 1
causing an adsorption target component other than the hydrogen component to be adsorbed onto an adsorbent
Implementation Method 2
performing suctioning of a vacuum tank switched to a blocked state using a vacuum pump switched to a tank-operated state, thereby discharging off-gas in the vacuum tank and adjusting the vacuum tank to a negative pressure state
Implementation Method 3
the recovered off-gas is supplied to a combustion device
Data Source
AI summary
A method for hydrogen production by pressure swing adsorption that can increase the recovery efficiency of an adsorption target component while enabling an off-gas to be appropriately supplied to a combustion device is provided that can achieve a cost reduction and an increase in the efficiency of the combustion operation.