Method for producing high purity hydrogen
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Solution Overview
Problem
Current methods for producing high purity hydrogen, such as pressure swing adsorption (PSA) and cryogenic temperature swing adsorption (CTSA), are inefficient in terms of energy and regeneration gas requirements, and lack integration with upstream processes, failing to meet the purity demands of certain applications like electronics manufacturing.
Innovation Solution
A process combining cryogenic temperature swing adsorption (CTSA) and cryogenic wash column (CWC) techniques, with recycling of streams to enhance PSA performance, utilizing online adsorbers and liquid hydrogen scrubbing to achieve high purity hydrogen production with reduced energy consumption and improved recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CTSA process is used to achieve high purity hydrogen, then hydrogen purity is improved to less than 1 ppm impurities, but energy consumption and regeneration gas requirements increase
Solution Approach 1:
The spent regeneration gas from CTSA is recycled back to the PSA unit as purge gas. This self-service approach allows the CTSA regeneration process to utilize its own waste stream, reducing the need for additional pure hydrogen for regeneration and lowering overall energy consumption.
Solution Approach 2:
Instead of discarding the spent regeneration gas from CTSA, it is recovered and reused in the PSA unit. This recovery strategy converts what would be waste into a useful resource, reducing the total hydrogen consumption and energy requirements of the overall purification process.
2Manufacturing precision
If liquid hydrogen supply is used to produce high purity hydrogen, then hydrogen purity is improved, but logistics challenges and costs increase
Solution Approach 1:
The mechanical/physical system of liquid hydrogen storage and transport is replaced with a chemical process system (CWC or CTSA) that generates liquid hydrogen or cryogenic conditions on-site. This substitution eliminates the need for complex liquid hydrogen logistics while achieving the same purification effect.
Solution Approach 2:
The hydrogen purification system is designed to perform multiple functions: purification, cryogenic cooling, and potential liquid hydrogen generation. This multi-functionality eliminates the need for separate liquid hydrogen supply infrastructure, reducing logistics complexity and costs.
3Manufacturing precision
If CTSA process is used to achieve high purity hydrogen, then hydrogen purity is improved to less than 1 ppm impurities, but equipment cost and operation complexity increase
Solution Approach 1:
The CTSA and PSA processes are merged into an integrated purification train, where the PSA pre-purifies the hydrogen before it enters the CTSA unit. This combination allows the CTSA to focus only on trace impurity removal, simplifying its design and operation while achieving the required purity level.
Solution Approach 2:
The PSA process performs preliminary purification to remove bulk impurities before the hydrogen enters the CTSA unit. This preliminary action reduces the impurity load on the CTSA, allowing it to operate at lower complexity with simpler equipment while still achieving less than 1 ppm purity.
4Manufacturing precision
If CTSA process is used to achieve high purity hydrogen, then hydrogen purity is improved to less than 1 ppm impurities, but regeneration gas requirement increases
Solution Approach 1:
A feedback loop is established where the spent regeneration gas from CTSA is monitored and recycled back to the PSA unit. This feedback mechanism ensures that the regeneration gas is not wasted but instead reused to purge the PSA adsorbent, reducing the total quantity of regeneration gas required.
Solution Approach 2:
The CTSA regeneration process serves itself by generating spent regeneration gas that is automatically recycled to the PSA unit. This self-service arrangement reduces the external hydrogen requirement for both PSA and CTSA regeneration, minimizing the total regeneration gas quantity needed.
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
The process achieves high recovery of hydrogen with reduced energy costs and improved purity, integrating effectively with upstream PSA processes to meet stringent purity requirements for various applications.
Implementation Method 1
a hydrogen stream containing trace carbon monoxide is passed through an active material comprising nickel and/or copper to reduce the carbon monoxide concentration of the hydrogen product to less than 1 ppm. The TSA process removes carbon monoxide via chemisorption in which carbon monoxide forms a chemical bond with the material surface, as opposed to physisorption in which impurities adsorb to the material surface by weaker van der Waals forces.
Implementation Method 2
The TSA process removes carbon monoxide via chemisorption in which carbon monoxide forms a chemical bond with the material surface
Implementation Method 3
Haringhuizen et al. (U.S. Pat. No. 2,975,605) teach a process for the purification of hydrogen, in which residual amounts of impurities such as nitrogen, carbon monoxide or argon are deposited in the solid form in a cryogenic heat exchanger.
Data Source
AI summary
A hydrogen feed stream comprising one or more impurities selected from the group consisting of nitrogen, argon, methane, carbon monoxide, carbon dioxide, oxygen, and water, is contacted with liquid hydrogen in a cryogenic wash column (CWC) process that produces pure hydrogen with high overall recovery. The waste liquid stream leaving the CWC may be used to improve the performance of upstream hydrogen processing steps.