In the coal-to-hydrogen plant, the outlet temperature is high during PSA adsorption, and the CO level exceeds the limit
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My facility is a coal-based hydrogen production plant with a design capacity of 33,000 cubic meters per hour. During recent operations, it was observed that among the eight adsorption towers in the PSA unit, which operate based on the 8-1-3 principle, the purity of the hydrogen product always decreases during adsorption in one particular tower; the CO level is particularly high, exceeding the allowed limits. The outlet temperature is normal at 30 degrees, but it rises to 50 degrees during adsorption in this tower. The CO2 level is normal. When the tower is operated separately, the pressure is maintained properly, with no leaks inside or outside the tower. I would like to know where the problem might lie
It is preliminarily judged that the problem tower experiences abnormal water content in the feed gas during operation; as operation time increases, water vapor rises and the packing absorbs water, releasing heat in the process.
There are a total of 8 towers; does the feed gas need to be mixed with water only when it reaches that specific tower for adsorption? The adsorption processes in the other towers are working normally
This concept is known as adsorption heat; the heat released when the adsorbent absorbs water is quite high. Some time ago, I worked on a system that involved vacuum distillation, back-pressure release, and a device for recovering and reusing the gas emitted from the vacuum pump. During operation of this system, pressure built up in the exhaust pipeline leading to the discharge area (resulting in abnormal conditions in the subsequent processing steps). The gas coming out of the vacuum pump was sent back into the adsorption tower through the back-pressure release pipeline, which caused the adsorbent to heat up and the packing material to sinter into clumps. If it’s not a vacuum system, it is likely that the heat generation tower is in operation with excessive water content in the feed gas, exceeding the adsorbent’s capacity to handle water.