Regenerative thermal adsorption for siloxane removal

Siloxanes are semi-volatile compounds present in biogas at room conditions that decompose at high temperatures (such as those obtained in cogeneration engines, turbines and boilers) generating silica particles that are very abrasive and damage recovery equipment energetic.

The operation of the BGAK system is based on "Regenerative Thermal Adsorption". Thus, the VOCs (Volatile Organic Compounds) and siloxanes present in the biogas are captured by an adsorbent environment at room temperature and once this environment is saturated, it is regenerated by air at over 90-120ºC.


In this way, operating costs of this process are achieved much lower than if it were carried out using activated carbon, which is the usual procedure. In addition, the adsorbent environment lasts over 5 years, so the maintenance of this equipment is much easier.


SUEZ Air & Climate works together with the manufacturer Parker, in the sale of this equipment in Spain.


Low-cost, high-efficiency technology

AIRDEP (the company SUEZ works with in Spain) has developed a new technology with a very low installation and operating cost.


Essentially, the new technology consists on a gas scrubbing tower to desulfurize the biogas and a soda regeneration process. The tower is composed of filling material that favours a close contact between the washing liquid (soda) and the biogas and, in this way, the hydrogen sulfide (H2S) present in the biogas is eliminated.


Once the washing liquid has passed through the absorption tower (also taking the H2S from the biogas), it reaches the rear tank where oxidation occurs through oxygenation. In this tank, the recovery of the previously used soda is produced, which is recirculated again to the first absorption stage. From this second stage, sulfur is obtained in elemental form, not dangerous and revaluable.

Its main advantages are:

  • Very high H2S scrubbing efficiency
  • Optimal system for very high H2S concentrations in biogas
  • Very low OPEX
  • It does not present clogging problems like other systems, and therefore, its maintenance is easier.

Secado y acondicionamiento del biogas

SUEZ Air & Climate works together with the manufacturer Parker, in the sale of this equipment in Spain.

Biogas drying and conditioning equipment
Diagram of operation of a biogas drying and conditioning system