Patent ID: 8016914

Claim:
A method of controlling an adsorbent bed unit comprising: measuring an adsorbent bed concentration of an impurity within an adsorbent bed of the adsorbent bed unit, the adsorbent bed adsorbing the impurity from a feed stream fed into the adsorbent bed, thereby to produce a product stream containing a product concentration of the impurity no greater than a targeted product concentration; the adsorbent bed unit being operated in accordance with a cycle during which the feed stream is fed to the adsorbent bed and thereafter, the adsorbent within the adsorbent bed is regenerated through desorption of the impurity, the cycle incorporating a feed cycle time during which the feed stream is introduced into the adsorbent bed, the impurity is adsorbed and the product stream is produced; controlling the product concentration within the product stream by calculating the feed cycle time employed within the adsorbent bed unit so that the adsorbent bed concentration tends to approach a targeted adsorbent bed concentration that will maintain the product concentration at a level no greater than the targeted product concentration and using the feed cycle time within the cycle after having been calculated, the feed cycle time being calculated so that the feed cycle time will decrease as the adsorbent bed concentration increases and will increase as the adsorbent bed concentration decreases; and the adsorbent bed concentration being measured within the adsorbent bed, at a location thereof, at which the adsorbent bed concentration will change before the product concentration of the impurity within the product stream changes in response to a disturbance so that controlling the adsorbent bed concentration to maintain the adsorbent bed concentration at the targeted adsorbent bed concentration will also maintain the product concentration of the impurity within the product stream at level no greater than the targeted product concentration.