The Solution

Various methods have been employed in an attempt reduce the effect of the silicon dioxide deposits in engines used by the landfill and sewage industries. Fluid injection systems do allow the silicon matrix to soften making removal easier, however in the long term it is preferable to filter the Siloxanes from the gas before they reach the engine preventing the formation of deposits.

Active carbon filtration systems are available which filter the contaminants for a finite period, these can be large installations (sometimes requiring planning permission) and need manual removal of spent activated carbon and disposal of the contaminated medium.

Recently, derivatives of the active carbon principal have been developed which offer a cartridge / silo replacement and removal service of the spent carbon. Although this avoids some of the disposal and safety issues, it is costly and requires constant maintenance. Normally these installations have a large footprint and require site planning before commissioning.

The PpTek BioGas AK (BGAK) Siloxane Removal System is a small (1.8mx2.3mx4.1m) self-contained unit that automatically regenerates the filter medium and requires a minimum of ongoing maintenance. The siloxane filter units, under normal conditions, will absorb Siloxanes for up to 3 years before the medium requires replacement. The PpTek siloxane removal system is automatically regenerated at regular intervals, the resulting regenerated air is composed mostly of high boiling Siloxanes that are believed to be non-ozone depleting in the stratosphere and have negligible global warming potential due to their short atmospheric lifetimes (e.g. Swanson et al.,1996). The US EPA has granted VMS compounds exemption from regulation as VOC ozone precursors. Siloxanes have been shown to degrade rapidly in the presence of soil (Carpenter et al 1995) with more than 50% converted to a water soluble fraction after 4-6 weeks.

The PpTek BioGas AK Siloxane Removal System is cost effective to operate, removes the problem causing Siloxanes, is environmentally friendly and enables engines to be run to their full potential between service intervals and overhauls.