Extraction of clean air from stratified porous lava
Jóhannes Loftsson, 2013-08-13

High concentration of H2S pollution near geothermal power plants can be critical for electronics and affects the air quality of workers.  The current practice at Reykjanes Power Plant is to remove the H2S from the air through use of purafil particulate filter in the ventilation system.  This is a costly and unclean process, which requires regular maintenance, and the used material needs to be treated with care when disposed.

An alternative method of providing clean supply air was investigated.  It consists of extracting air from a shallow drill hole through stratified porous lava.  The tests are ongoing, but the initial results are promising.  All H2S is removed and the earth filtered air has low concentration of particles, (almost sufficient for cleanroom ISO 4 standard).  The air salinity of the extracted air is very low and the temperature and relative humidity do not fluctuate with ambient air. 

This cleaning method is clean by nature, avoiding unhealthy maintenance work as no waste is produced.  Some additional operational benefits come from having non-corrosive air with stable thermodynamic properties.

A much wider range of use of this method may be possible.  Removal of urban and industrial pollution from ventilation is a global problem.  The additional benefits of easy maintenance and energy cost savings in heating and cooling make new approach especially attractive.