An adsorber vessel for use in the adsorption of a component from a gas and subsequent regeneration by thermally induced desorption of the component comprises an inlet for regeneration gas having an inlet nozzle containing at least one heater element, and an outlet for regeneration gas, the inlet and outlet for regeneration being separated by a flow path including a flow chamber containing a body of adsorbent, and wherein the body of adsorbent has a first end which is adjacent the inlet for regeneration gas and a second end which is remote from the inlet for regeneration gas, and the or each heater element is located so as not to penetrate through the first end of the body of adsorbent.