Yield of hydrogen purification by pressure swing adsorption
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For those involved in pressure swing adsorption hydrogen purification, let’s conduct a survey to find out what the hydrogen recovery rates are for PSA used on shifted gas and PSA used on reformed gas Let me start by saying that our PSA recovery rate for the transformed gas is 79% (after 10 years of operation), while it is 90% for the reformed gas
In the method of hydrogen production via methane reforming, the hydrogen recovery rate can exceed 75%. In the method of producing hydrogen using the dry gas generated as a by-product of the catalytic cracking unit in refineries, the hydrogen recovery rate can reach around 70%. The hydrogen recovery rate in the method of producing hydrogen from ammonia-absorbed off-gases can exceed 85%. The purity of hydrogen produced from coalbed methane can reach over 99.99%, but the hydrogen recovery rate is only around 56%.
Reference: 【In the method of producing hydrogen using dry gas generated as a by-product of catalytic cracking units in refineries, the hydrogen recovery rate can reach around 70%.】 】 What is the purity of hydrogen in the raw materials, and what is its purity in the final product? Is a 70% yield too low? The PSA unit that our factory plans to install will use hydrogen accounting for approximately 70% of the raw materials, with a product purity of 98%; the yield specified in the plan is 90–92%
I also want to know about this issue, as well as the processing capacity of the device and the operation mode of PSA. 12,000 NM3/h natural gas hydrogen production, 9-3-3, 99.5%, yield of 75% (in operation for nearly 10 years)
A yield of 75% is also relatively low. The yield issue is, firstly, related to the original design of the equipment. Compared to technology 10 years ago, today’s technology is more advanced. The yield issue, and secondly, it relates to the selection of molecular sieves. Ten years ago, adhesive-free 5A molecular sieves did not exist, and conventional 5A molecular sieves were used for PSA hydrogen purification. Today’s binder-free 5A molecular sieves have a stronger ability to adsorb impurities, and less purge hydrogen is required during the desorption process. It can help improve the hydrogen yield.
The person on the 5th floor is right; the key to PSA lies in the adsorbent, programmable valves, and the process flow. The choice of adsorbent plays a decisive role in the hydrogen yield.
Currently, most pressure swing adsorption technology providers guarantee 90–95%； Our plant also has a pressure swing adsorption decarburization system for gas with the following composition: H2 36~40%, CO2 22~26%, CO 28~32%, N2 2~5%, CH4 1~3%. This system uses a two-stage process, and the yield of H2 generally remains above 97%.
There are many factors related to yield, such as the composition of the feed gas, pressure, and the composition of the product gas; therefore, when discussing yield, other indicators should also be taken into consideration
Quoting Floor 4: I also want to know this question, as well as the processing capacity of the unit and the operation mode of PSA. Hydrogen production from natural gas at a rate of 12,000 NM3/h; 9-3-3 process, 99.5% efficiency, with a yield of 75% (the plant has been in operation for nearly 10 years). You can upgrade the facility – with the 9-3-3 process, the H2 yield can exceed 90%
Hydrogen production from natural gas at 12,000 NM3/h; 9-3-3 configuration, 99.5% efficiency. With an operating pressure of 0.8 MPa, this process can achieve 90% efficiency. I wonder what your operating pressure is?
The hydrogen yield is increasing steadily. Hydrogen is produced via shift reaction at a pressure of 0.8 MPA, with a H2 yield of 99.2% and a purity of 99.9%
Is it hydrogen production from reformated gas? The purity of the syngas used for hydrogen production seems to be low; a H2 yield of 99.2% seems exaggerated. I’m curious about the purity of the hydrogen used as raw material, as well as the purity of the hydrogen in the PSA off-gases If the hydrogen yield of PSA can truly reach over 99%, I feel that our PSA technology is quite outdated; its designed yield is only 90%. I would like to seek advice from those who are more experienced in this area.
The yield depends mainly on the process used; generally, the yield is 80-85% for the flushing process, while it’s higher for the vacuum process. Additionally, it depends on how many times pressure equalization is carried out
Currently, a hydrogen production yield of 95% is already quite high. I’m really curious to know where those high-yield systems mentioned by the people above are located; in particular, the two-stage hydrogen production process on the 7th floor – with such a low hydrogen content in the feed gas, a 97% yield seems unimaginable. Could you tell me how many columns are used in total?
Could this expert provide some detailed guidance on how to learn PSA? All I came across were general descriptions in the operating procedures
I also want to know about the issue of low yield in two-stage hydrogen production