Method for the adsorptive drying of purified biogas and for regenerating laden adsorbents

Abstract

In a method for adsorptively drying purified biogas and regenerating laden absorbents, foreign matter is not allowed to enter the purified biogas, the content of methane in the gas remains virtually unchanged and the effort involved in regenerating the laden adsorbent is reduced. Drying and regeneration are effected in a closed biogas cycle, wherein separate layers based on silica gel and molecular sieves are used as the adsorbent. The biogas to be dried first flows through the silica gel layer. The adsorbent is regenerated with exclusively heated, dried biomethane having a temperature of up to 150° C. which, after contact with adsorbent, is recirculated to the outflow of purified biogas. After regeneration, the bed is cooled by biomethane, which is subsequently recirculated to the outflow of purified biogas. Methane-containing water accumulating during drying and regeneration is recirculated to the biogas generation and/or purification.