Removal of contaminants with ozone

摘要

Contaminants, particularly NO x , are removed from a flue gas stream by reaction with ozone in a suitable reactor. The NO x is converted to N 2 O 5 which can be readily absorbed in an aqueous scrubbing liquid. The ozone is provided in an ozone-containing gas stream which is generated from an oxygen-containing gas stream and subjected to separation to remove oxygen. The so separated oxygen is used to generate further ozone. The concentration of ozone in the ozone-containing gas stream is preferably 6% by weight or less.