| 摘要 |
A PSA process for the pre-purification of air to remove water vapour and carbon dioxide prior to introduction into an air separation unit, comprises in cyclical sequence, feeding air into the bottom of bed A containing adsorbent effective to remove water vapour and carbon dioxide from the air and withdrawing purified air from the top of bed A (valves 1 and 3 open) while first regenerating bed B first by venting it to atmosphere (valves 8 and 9 open), second evacuating it (valves 8 and 10 open), and third purging it with a (nitrogen) stream from the air separation unit while continuing the evacuation (valves 6, 8 and 10 open); at the end of the purge step, passing purified air from the top of bed A into the top of bed B (valves 1, 3 and 4 open); using bed B for production of pure air (valves 2 and 4 open) while subjecting bed A to first a vent to atmosphere (valves 7 and 9 open), second evacuation (valves 7 and 10 open), and third a combined purge/evacuation (valves 5, 7 and 10 open); and then passing purified air from the top of bed B into the top of Bed A (valves 2, 3 and 4 open). The three-step regeneration sequence described above makes it possible to reduce the consumption of purge gas and reduce bed size in comparison with comparable processes known from the prior art. <IMAGE> |
