PSA: What to do if the hydrogen content in the gas is too high?
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The hydrogen content in the PSA purified gas of the dry gas hydrogen production unit is too high (in our company it is ≤29). What is the cause, and how should it be addressed? Can the adsorption time be reduced by extending it?
Personally, I think there are two scenarios: 1. A short adsorption time results in a low content of impurities in the desorbed gas. 2. The high pressure at the end of the forward process leads to an excessive amount of hydrogen being used for flushing, resulting in a high hydrogen content in the purge gas. Welcome to all experts to discuss together
Long adsorption time, high backpressure, multiple purge gas sources, partial saturation of the adsorbent – replace the adsorbent! The temperature in the PSA is high, resulting in incomplete separation!
By extending the adsorption time, the initial load of the new device is low; as long as the hydrogen quality is satisfactory, there will be no issue with inadequate desorption of the adsorbent. Just extend the time.
Why extend the adsorption time?
Thank you... Why extend the adsorption time?
Firstly, the hydrogen content in your purified gas is high; this issue can be resolved by extending the adsorption time. There is no dispute about this – as long as the product is of good quality, it is possible to appropriately extend the adsorption time. Secondly, with new devices, it’s possible to adjust the sequential air release; with old devices, there’s no need to try to do that. Thirdly, when adjusting the adsorption time, make small changes rather than drastic ones; adjust it gradually. Avoid changing the time by too much at once, as this could result in the hydrogen produced not meeting the required standards, which would be counterproductive.
Thank you... but I don’t quite understand why extending the adsorption time is necessary when the hydrogen content in the gas to be analyzed is high. Please explain
As the adsorption time increases, the product purity decreases, while the hydrogen recovery rate increases. The adsorption time is reduced, product purity increases, and hydrogen recovery rate decreases. It should be written in this operation manual.