How is the time for each PSA step calculated?
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I used to work on hydrogen production for about a year, and PSA was also used for the purification of hydrogen. Although the people at Huaxi explained how to calculate the time required for each step of the PSA process, the explanation was brief and not detailed enough, so I never really understood it. We use an 8-2-4 process, with a processing capacity of 3000 cubic meters per hour and an inlet pressure of 2.1 MPa. Could that expert explain how the time for steps such as 1st to 4th averaging, rinsing, forward playback, and reverse playback is determined? People from West China originally wrote down a few formulas, but I didn’t manage to write them down. My current job is also related to PSA, so I want to understand them! ! ! This post was last edited by ququ629 on 2008-7-4 11:10]
Why isn’t anyone participating? I’m not sure if I can organize some kind of event to encourage people to get involved!
The formula is unknown; settings are made based on principles and empirical values: Time Sequence, Meaning, Default Value, Setting Principle. T1: Average time for first and third cycles – 25 seconds; this ensures that the pressure levels in both towers are equal. T2: Average time for fourth cycle – 25 seconds; this also ensures equal pressure levels in both towers. T3: Time for forward and reverse operation – 80 seconds; this value should be as long as possible while still maintaining acceptable product purity. T4: Forward operation time – 25 seconds; this is sufficient to reduce the pressure in the adsorption tower to 0.25 Mpa (T4 must be less than T3). At the start of operation, T3 is usually set to a shorter value; it is increased later after observing the product quality and the pressure equilibrium curve. During normal operation, the T3 time can be adjusted based on the amount of processing and the quality of the product; the other times are set to the shortest possible value (the time required for maximum processing), and generally no further adjustments are made.
Why isn’t the second mean included in your data on the 3rd floor?
Could you provide more detailed information? Follow this post!
Both are T1+T2, so there is no need to list them separately. When scheduling, it is generally sufficient to consider the individual T1~T4 times only. This post was last edited by xjksh on 2008-6-16 01:23]
There is no fixed time for setting it; the time is determined and adjusted based on the voltage equalization conditions or the pressure levels at various process stages
Is there no fixed time for it? At the very least, there should be a theoretical calculation value, and then adjustments can be made based on actual conditions; otherwise, how can you set the time and conduct experiments arbitrarily?
Depending on the size of the adsorption tower, there is a certain time at a rated flow rate. During actual operation, the time is determined based on the relationship between the actual flow rate and the rated flow rate.
I’ve also been troubled by this issue. The seniors either keep it confidential or something; the usual answer is to rely on experience values. However, for different devices, with varying processing capacities and operating pressures, as well as the number of equalization cycles, there should be different time durations. For T1, T2, T3, etc., these values are generally set using the operation status table of the adsorption tower. Let’s take a simple example: Steps 123456789101112 T1 T2 T1 T2 T1 T2 T1 T2 T1 T2 T1 T2 AA A E1 D E2 D E3 D P P/DP P E3 R E2 R E1 R F R B E1 R F R A A E1 D E2 D E3 D P P/DP P E3 R E2 R C E3 R E2 R E1 R F R A A E1 D E2 D E3 D P P/D P P D P P E3 R E2 R E1 R F R A A E1 D E2 D F E1 D E2 D E3 D P P/DP P E3 R E2 R E1 R F R A A. Here, T1 represents the time for the 1st equalization and the 3rd equalization, while T2 represents the time for the 2nd equalization. T1 + T2 constitutes the adsorption time for a single tower. As for the specific times, I think there should be at least a theoretical calculation based on what the original poster mentioned. I hope experts can give some guidance
Timed post: http://bbs.hcbbs.com/thread-231783-1-3.html. In fact, the time required for pressure equalization is indeed an empirical value, hehe:lol. 1. A longer pressure equalization time leads to more dilution of the heavier components, which is not favorable for recovering those components. 2. A shorter pressure equalization time results in incomplete recovery of the lighter components, which is not advantageous for their recovery. 3. Generally speaking, there is some waste of time during pressure equalization; it’s sufficient to control properly the adsorption time as well as the time required for evacuation or release. This post was last edited by Uncivilized on 2008-7-23 at 19:00