There are at least six methods for removing siloxane from biogas, which were used at least at the pilot stage and which can be considered to prevent gas engines and turbines from preventing the siloxane from being damaged.
These methods can be used to process biogas prior to the use of landfill gas in incinerators (EfW).
This remarkable range of methods is described below, including the following:
1. Activated carbon technology
Activated carbon is widely used to remove organic matter from gases and liquids because it has excellent adsorbing properties and a large surface area.
2. Activated alumina method
The siloxane contaminants are theoretically removed by passing biogas through a layer containing activated alumina, which absorbs siloxanes. Aluminum always reaches saturation, at which time it is decommissioned and regenerated and reused.
3. Cooling and / or condensation
Condensation cooling in combination can be used to preferentially remove selected compounds by lowering the temperature or pressure of the gas and allowing the liquid to bond and precipitate.
Condensation methods are achieved either by cooling or by relieving pressure in a hermetic system.
4. The use of synthetic resins
Synthetic resins can remove VMS by adsorption to their surface structure at the molecular level. It is reported that the resins used have a surface area density similar to activated carbon, and are designed by design to remove certain classes of compounds.
5. Liquid absorbents
Liquid scavengers may be suitable for this service and have been reported to have been used in at least seven facilities throughout Europe to remove organic compounds, including siloxane, from landfill gas.
6. Membranes
Membrane technology is a technology that has recently moved into many areas of processing, and reportedly involved several small plants for processing biogas to the quality of main gas / gas using membrane technology. Concerns will exist, although regarding the possible damage to the membranes by the acidic nature of biogas in general.
