A problem in PSA for hydrogen production
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We have a hydrogen production unit that uses catalytic dry gas and coking dry gas as raw materials, with an output of 20,000 standard cubic meters per hour. In order to comply with the guidelines set by our group’s leadership regarding energy savings and reduced consumption, we tried to reduce the purity of the hydrogen produced by the PSA process; however, this approach did not yield significant results. Does anyone among you know of a better method?
It wasn’t made clear that the hydrogen purity in the analysis gas of PSA was reduced to its lowest level
It is necessary to minimize the purity of the hydrogen product, as long as the process requirements of the downstream hydrogen-using equipment are met. For example, if the PSA process can produce hydrogen with a purity of 4 nines, but the downstream equipment only requires 2 nines, then the hydrogen produced by PSA does not need to be that pure. But of course, the most effective method is to change the absorption time of PSA, by extending it appropriately – increase it by 5 seconds at a time; it should work.
What the original poster means is that the adsorption time was adjusted, but the effect wasn’t very noticeable. It is recommended to adjust the outlet temperature of the conversion furnace and keep it at the minimum level; then adjust the water-to-carbon ratio as well in order to reduce the hydrogen purity in the conversion gas. Let’s see how that works
What 4# said makes sense too. If it is a new catalyst, its activity should be high, allowing for a lower conversion temperature to be used, which helps save fuel. Try not to change the water-to-carbon ratio; at least don’t increase it significantly. A higher water-to-carbon ratio reduces the efficiency of the converter and increases fuel consumption.
When adjusting the hydrogen purity of PSA-produced hydrogen, as long as the levels of CO+CO2 in the hydrogen do not exceed the specified limits, the hydrogen purity can be reduced to lower levels. Excess amounts of CH4 have little impact on the hydrogen-using equipment downstream; what is important is to control the levels of CO+CO2. Typically, CO+CO2
The adsorption time can be adjusted; if the effect is not significant, the adsorption pressure can also be adjusted accordingly
Our company is also building a continuous reforming project this year, along with a PSA unit.