Abstract: An adsorption-desorption process for the recovery of hydrogen from a feed gas containing trace pollutants adapted to be strongly adsorbed, in concentrations generally below 1% by volume and containing components adapted for only light adsorption, in concentrations above 1% by volume is operated through a preliminary first adsorption stage for the strongly adsorbable trace pollutants and a second main adsorption stage for the light adsorbable components and for the discharge of hydrogen. Contrary to the prior art where the adsorption-desorption was effected by alternating high pressure and low pressure cycles in the main adsorption stage only, the pressure cycles in the present case are carried out both in the preliminary first adsorption stage and in the second main adsorption stage, preferably by arranging the two adsorption states in series. The process substantially extends the service time of the adsorber used in the first adsorption stage.

Abstract: The present process is an improvement of an earlier process wherein a nitrogen enriched gas is obtained from a gas containing oxygen and possibly other components. In that process the feed gas is passed in a continuous flow cycle through an adsorber containing carbonaceous molecular sieve coke followed by evacuation of the adsorber, oxygen and possibly other gas components being adsorbed and the discharged nitrogen-enriched gas being collected until the continually rising oxygen contents thereof reaches a predetermined limit value whereupon the molecular sieve coke is desorbed of the residual gases prior to the next charging cycle. The present improvement is constituted by the feature that the flow of feed gas through the molecular sieve coke is effected at a continually increasing pressure until a terminal pressure of about 3 to 10 bar has been reached.

Abstract: A process for the purification of waste water containing dissolved organic carbon contaminants which comprisesA. passing the waste water upwardly through a column of activated carbon particles,B. determining the total organic carbon content of the water before it enters the column and simultaneously at a location that is between 30 and 70% of the total height of the carbon particles in the column,C. continuously withdrawing the spent carbon particles from the bottom of the column at such a rate as to maintain an essentially constant preselected difference between the total organic carbon content of the water as it enters the column and at the preselected location that is between 30 and 70% of the height of the carbon particles in the column,D. continuously introducing fresh activated carbon particles or reactivated carbon particles at the top of the column at such a rate as to compensate for those withdrawn at the bottom of the column, andE. removing the purified water at the top of the column.