This process builds upon conventional methods by incor-porating nitrogen purifcation. During the desorption of the
adsorption purification bed,non-condensable gases after condensation (freezing) are treated in a "nitrogen purifcation bed" for adsorption and purifcation. The organic compounds are adsorbed in the "nitrogen purification bed", while the nearly pure nitrogen desorption stream is heated and returned to the adsorption purifcation bed for cyclic heating and desorption. (Note: Depending on the context,"nitrogen purifiyng unit"or "nitrogen adsorption bed." Adjust if needed for technical accuracy.)