Adsorptionstorkar

Adsorptionstorkar are industrial gas-drying devices that use adsorption to remove moisture and certain volatile contaminants from gas streams. The term combines adsorption with 'torkar' meaning dryer in some Scandinavian languages, and in English-language literature may be described as adsorption dryers. They are used where ultra-dry gas is required.

Principle: A moisture-laden gas passes through a column containing an adsorbent such as activated alumina, silica gel, zeolites, or activated carbon. Water and other polar molecules preferentially adsorb on the surface; the gas leaving the bed has reduced humidity. Temperature and pressure influence capacity; the process is described by adsorption isotherms (Langmuir/Freundlich).

Operation: Most systems operate cyclically. In fixed-bed TSA or PSA, one bed adsorbs while another bed is regenerated by heating or reducing pressure, transferring desorbed water vapor to a condenser or to a regeneration stream. Some designs use rotating wheels (rotary adsorption) to continuously cycle adsorbent. Regeneration energy is a key factor; some modern units use heat recovery from the drying exhaust.

Applications and performance: Widely used for natural gas dehydration, pipeline quality air, semiconductor manufacturing, pharmaceutical drying, and food packaging. They can achieve dew points well below freezing, depending on adsorbent and cycle design. They offer high selectivity and low waste streams, with minimal chemical usage, but adsorbent aging and capacity loss require periodic replacement or reactivation.

Limitations and development: Pressure drop, moisture breakthrough, and sorbent degradation impose operational constraints. Ongoing research focuses on advanced zeolites, composite adsorbents, and energy-efficient regeneration methods such as pressure-swing with heat recovery and vacuum-assisted cycles.