Hydrogen recovery
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Gentlemen! Our facility produces synthetic ammonia from coal; the designed vent gas volume is 757 m3/h, and after ammonia is recovered, hydrogen and nitrogen are sent to the flare – approximately 70% hydrogen and 28% nitrogen. We now want to recover the hydrogen, with a flow rate of around 500 m3/h. The profit generated from this, when converted to effective gas terms, amounts to 5 million yuan per year. However, to carry out this recovery, the hydrogen at 0.5 MPa needs to be pressurized to 5.5 MPa, and the low flow rate makes it difficult to select appropriate equipment. Does anyone have any good suggestions regarding recovery methods? ! !
What process was used earlier? We have gas cylinders here, which can be used to purify hydrogen and send it into the cylinders for recovery.
This post was last edited by bookjude on 2020-1-7 at 13:34. Hydrogen can be recovered using pressure swing adsorption on a scale of this kind, and the hydrogen can be purified to over 99.9%.
PSA can be used to pressurize the shift inlet.
For the water-coal slurry gasification process, we don’t have gasification tanks.
What equipment is needed for such a small capacity? I’d recommend it.
How high is the pressure in ammonia synthesis? The small hydrogen-nitrogen compressor is directly combined with the make-up gas to return to ammonia synthesis.
The inlet pressure of the syngas compressor is 5 MPa, the pressure for ammonia washing in the vent gas is 0.5 MPa, and the remaining hydrogen is discharged to the flare. Pressure elevation is required, but it seems difficult to select an appropriate unit for such a small volume of gas.
It’s difficult to choose the right model; consult a compressor manufacturer for customization.
Could you recommend some better manufacturers?
For this specific operating condition, there is no standard model available; it must have been custom-made. Thirty years ago, in domestic small urea plants, the hydrogen and nitrogen compressors were equipped with make-up gas units to handle any excess gas volume; at that time, Changsha and Shenyang had companies that specialized in manufacturing such compressors. It’s not clear whether this service is still available today.