Is vacuum desorption or passive desorption better for pressure swing adsorption?
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The company is planning to install a new set of pressure swing adsorption hydrogen production equipment. Currently, there are two processes available: vacuum pump desorption and gravity-fed flushing. Those who have used these processes could share their opinions – which one is better? ?
I’m not sure about this “passive flushing” process; it would be best to send a simple diagram. It is only by understanding the principles of the process that one can draw conclusions. These days, it’s common for some merchants to take things out of context on production lines; therefore, one should choose carefully for reference.
“\"Non-powered flushing\" refers to a process that uses multiple pressure equalization and flushing steps without employing a vacuum pump for desorption, yet it can achieve yields that are equal to or even exceed those of vacuum desorption.
Repeated voltage equalization requires more containers and packing, as well as the energy consumed to increase the pressure. Compared to energy consumption, construction costs, and subsequent costs for filler replacement are all issues that deserve consideration.
Personal opinion: VPSA uses vacuum-based desorption and is generally applied in situations where the hydrogen purity is relatively low and the feed composition is complex, making desorption difficult. The recovery rate will be a few percentage points higher than that of PSA; relatively speaking, the investment costs and operating/maintenance costs are much higher than those of PSA. Whether it is cost-effective depends on the actual circumstances. However, not many go to VPSA
I agree with what the guy on floor 5 said – the choice of process depends on the hydrogen content in the feed gas. I have both VPSA and PSA systems here; the hydrogen content in the feed gas for VPSA is around 30%, while it’s around 80% for PSA. VPSA consumes a lot of electricity because it has a vacuum pump, and a compressor is required to boost the pressure of the desorbed gas and send it to the gas pipeline network. For PSA, a desorption gas compressor is sufficient
The main thing to consider is whether you have higher requirements for purity or for yield. It will then involve different processes. Hangzhou Jingwang specializes in hydrogen production from methanol, PSA purification, and hydrogen production from natural gas
It depends on how hydrogen is used. If the hydrogen production unit needs to operate at a low load for extended periods due to the requirements of the main processing system, it is recommended to use a vacuum extraction process. Someone mentioned earlier that the yield with vacuum extraction is 90%, but this is incorrect; a well-designed and properly operated VPSA system can achieve a stable hydrogen yield of 94%. By using a two-stage approach combined with vacuum extraction, the yield can reach 96%； If full-load operation is required, it is recommended to use a purging process
It depends on the hydrogen content of your raw materials; we use methanol to produce hydrogen, and both VPSA and PSA methods are employed
It’s the rinsing process and the vacuuming process