Pressure swing adsorption in hydrogen production plants
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I spent the entire afternoon looking at the hydrogen production PSA unit, but I still couldn’t understand it. I would like to ask the experts for some guidance on a few issues: Our unit operates using a 10–2–4 process, and I have the following questions: 1. If I know the operating sequence of one of the adsorption towers, for example that tower A is in the adsorption phase, can I determine the sequence of operation for the other towers? In other words, is there any pattern such that knowing the operating status of one tower allows one to determine the operating sequence of the other towers? The operating procedures state that there should be a difference of one-third in the adsorption time between the various towers; I don’t understand what this means. 2. Could someone explain to me what those time parameters mean? Time sequence, meaning, preset value, and setting principle: 10Time1 – average time for stages 1 and 3; a duration of 30 seconds ensures that the pressures in the two towers are equal during these stages. 10Time2 – average time for stages 2 and 4; a duration of 90 seconds ensures that the pressures in the two towers are equal during these stages. Note: Total adsorption time per tower = 2x(10Time1 + 10Time2); flushing time per tower = 2x(10Time1 + 10Time2); reverse flow time per tower = (10Time1 + 10Time2). As long as the adsorption time remains unchanged and equal pressure can be maintained, 10Time2 should be extended as much as possible to ensure a smoother final rising process. I simply can’t understand it at all – how can the total adsorption time of a single tower be related to pressure equalization and sequential operation? Or rather, how were these formulas derived? In normal operations, when adjusting the T2 time based on the purity of the product hydrogen, what exactly does that refer to? Let’s ask so many questions for now. Share whatever you know, and thank you in advance! ! !
Pressure swing adsorption is also a specialized field; when I first started working in our company, I spent about a month studying the theory behind it.
Well, I spent a long time looking at it, but it seems like my understanding is quite superficial; it feels like I’m just wandering around the entrance without really gaining any insight
It’s not possible to explain this thing in just a few words; you need to read the operation manual more carefully. Also, many things will become clear once you start using it in practice. Don’t worry – PSA is simple to operate and easy to handle. Of course, if you want to master it, you’ll need to put in some effort
I am also learning pressure swing adsorption, and I hope to exchange ideas. QQ 765471892
No abnormal situations have occurred; growth happens more rapidly when such situations do arise. In previous years, our systems experienced frequent tower switches, and the programmable valves would often get stuck in winter. Now, everyone on the team is an expert in PSA technology.
The 10—2—4 process indicates: 10 towers in operation, 2 towers adsorbing simultaneously, and 4 pressure equalization steps. What you mentioned can be calculated, but it’s a bit troublesome. If you have any ideas, leave your contact information and I can send it to you.
Send it to my QQ email address: 361626246@qq.com
Look at the total number of steps – PSA is automatic. For example, if there are 30 steps, then those 30 steps constitute one cycle which is repeated. The operating condition of each tower remains constant; you just need to observe this carefully. Additionally, the adsorption time is equal to the sum of T1 + T2 + T3; therefore, the length of the equalization time definitely affects the adsorption time.
The sequence of operations for each tower can be determined. First, it is necessary to understand the 20 possible sequences for a single tower (adsorption, first level of pressure reduction, second level of pressure reduction, third level of pressure reduction, fourth level of pressure reduction, forward discharge 1, forward discharge 2, forward discharge 3, reverse discharge, flushing 1, flushing 2, flushing 3, fourth level of pressure increase, third level of pressure increase, second level of pressure increase, first level of pressure increase, and permanent operation). Next, by following the order in which the adsorption towers are switched (A--F--B--G--C--H--D--I--E--J), it is possible to determine the sequence of operations for each tower, including the status of the relevant valves. The second question is also easy to understand. Assuming that A is in the adsorption phase, and once adsorption is complete it will switch to tower B; therefore, during the time when A is adsorbing, tower B must go through its regeneration process, that is, it needs to complete three equal-pressure rises, two equal-pressure rises, one equal-pressure rise, and the final pressure rise – in other words, T1+T2+T1+T2. Extending the duration of one of the steps in Tower B means extending the adsorption time of Tower A.