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Siloxanes 101

While composed primarily of methane and carbon dioxide, biogas also contains a host of contaminants including moisture, hydrogen sulfide, and Volatile Organic Compounds (VOCs). The most problematic VOCs are called “siloxanes” which are a family of man-made organic compounds used in the manufacture of cosmetics, hygiene products, foods, and industrial coatings. The use of these compounds is increasing rapidly - and so is their presence in landfills, waste water and food waste.


As the material in a landfill or digester decomposes and generates biogas, the siloxane molecules enter the biogas stream as a vapor.


In renewable natural gas (RNG) projects, the removal of siloxane and VOC vapors is critical to protect biogas upgrading equipment, and to meet the necessary gas quality specifications for pipeline injection. Pipeline operators have strict limits on siloxanes as they can contaminate the pipeline and cause significant damage to downstream equipment.


In biogas to power generation or combined heat and power (CHP) projects, siloxane and VOC reduction is equally important. During combustion these siloxanes undergo a phase change from a vapor to a solid silicon dioxide powder. This abrasive powder adheres to all surfaces downstream of the point of combustion, reducing heat transfer, blocking flow and increasing wear. In engines or turbines, this build up quickly reduces efficiency and will eventually causes total equipment failure. Frequent overhauls to remove this build up can significantly increase project operating costs and downtime. In fuel cells, microturbines, or any project requiring the use of post combustion catalysts, siloxane vapor reduction is an absolute necessity to prevent rapid and complete failure of the technology.

Fortunately, Willexa Energy's Regenerative Siloxane & VOC Reduction Systems offer a cost effective, guaranteed way to remove siloxane and VOC vapors, protecting your assets, reducing operating costs and downtime, and maximizing project profitability.

Top End with Siloxanes Biogas Engine
Siloxane / Silicon Dioxide Powder Deposits / Build Up on Caterpillar / Jenbacher Engine
Part / Valve Failure due to Siloxane Contamination of an Engine
Siloxane Build Up on a Spark Plug

The High Cost of Carbon

Activated carbon may adsorb siloxanes, but it also adsorbs VOCs, moisture, hydrocarbons, hydrogen sulfide, and many of the other contaminants found in landfill and digester gas. When used for bulk siloxane or VOC reduction carbon media rarely lasts more than a few weeks, and the downtime, labor, vacuum truck, replacement media and disposal costs can cost hundreds of thousands of dollars per year!


Regeneration is the answer. Our systems use a non-carbon based media that is regenerated automatically on site, lasting 18 - 24 months or more. Our engineers invented this technology and we have the longest and most successful history of any regenerative siloxane reduction provider. Contact us today and let us show you how our technology can improve the profitability of your biogas project.

Best Activated Carbon for Siloxane Removal Treatment in Landfill & Digester Gas & Biogas
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