Abstract: A process is disclosed for preparing a carbon molecular sieve used for the separation of oxygen from nitrogen, which comprises the steps of:(a) milling hard coal to a grain size of 95%<20.mu.m;(b) oxidizing the finely milled hard coal with air in a fluidized bed;(c) adding water and coal tar pitch as a binder and molding the finely milled hard coal into shape;(d) carbonizing the finely milled hard coal molded into shape in a rotary kiln at a temperature of 500 .degree.to 850.degree. C., with a dwelling time of 55 to 65 minutes, in order to obtain a carbonization product with a bulk density of 530 to 560 g/l;(e) activating the carbonization product with steam at to 900.degree. C. for 165 to 195 minutes to obtain a sintered carbonaceous product having a bulk density of 590 to 650 g/l; and(f) treating the sintered carbonaceous product at 750 to 850.degree. C. with carbon-splitting hydrocarbons to obtain said carbon molecular sieve.

Abstract: Process for obtaining nitrogen from air or nitrogen-containing gases by pressure exchange adsorption and desorption on two alternately operated adsorbers filled with carbon molecular sieves, whereby air is passed through the adsorber so that the oxygen is adsorbed and enriched nitrogen is obtained, while at the same time the other adsorber is regenerated by pressure relief, whereby in a first carbon molecular sieve layer (on the air intake side) of the two adsorbers, making up 1/20 to 1/2 of the entire carbon molecular sieve layer, a carbon molecular sieve A is introduced which serves simultaneously for the adsorption of the residual humidity and gas separation, and that in a second (on the air-outlet side) carbon molecular sieve layer a carbon molecular sieve B is introduced serving exclusively for gas separation, and that the carbon molecular sieve A has a relative volume of 3.0 to 3.4 and the carbon molecular sieve B has a relative volume of 2.3 to 2.95.

Abstract: Process to obtain nitrogen from gas mixtures containing oxygen and nitrogen by using alternating pressure adsorption on carbon molecular sieves, which comprises an adsorption cycle and a desorption cycle, in which the desorption cycle--which may also include the pressure equalization step--includes an idle time, which amounts to between 20 and 80% of the total time of the desorption cycle, plus a correspondingly shortened desorption step, whereby the adsorber decompression line is completely opened at the beginning of the desorption step and is completely closed and kept tightly closed after the decompression to ambient pressure during the subsequent idle period.

Abstract: Process for producing carbon molecular sieves for separating oxygen and nitrogen by treating a carbonaceous product with inert gas and steam in a vibrating oven and further treating said product with benzene at a high temperature in a vibrating oven to thereby narrow the existing pores.

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.