The Behaviour of Phosphorus Compounds and Their Effect on DeNOx-Catalysts in Coal Fired Power Plants
According to current legislation concerning the displacement of sewage sludge or of meat and bone meal their use as secondary fuel becomes increasingly attractive. These fuels, however, have a high phosphorus content. The co-combustion of these secondary fuels has caused an increased deactivation of the SCR DeNOx catalysts used for the flue gas dentrification. The increased deactivation rate caused unintended maintenance and replacement costs. Within this work, the release of gaseous phosphorus as well as of phosphorus bound on sub-micron particles during co-combustion is described. The effect of these species on the SCR catalyst is also investigated, whereas gaseous phosphorus appears to have the largest impact on catalyst deactivation. Furthermore, possible countermeasures are examined and further possibilities to minimised phosphorus deactivation are described to minimise catalyst maintenance costs when firing phosphorus-rich fuels.