Application of high consistency ozone bleaching in ECF sequences

Ozone bleaching has been applied in ECF and TCF bleaching sequences since the beginning of the 1990's. It has confirmed by actual data and laboratory tests that applying the ozone system in ECF sequence can save bleaching chemical costs and makes the plant with a very simple sequence without acid treatment or other treatment. In this paper, a simple comparison between high consistency (HC) and medium consistency (MC) ozone system, advantages for HC ozone system, actual plants and HC ozone system application in ECF bleaching sequences will be discussed. Especially, a discussion of a simple sequence of (Z (Eo)) DnD as a Light ECF sequence must be very interesting in view of its powerful effect, chemical savings, reducing effluent mount, pulp quality without having an additional acid treatment and chlorine dioxide stage.