Saving Energy by Application of Ozone in the Mechanical Pulping Process, 2007 International Mechanical Pulping Conference

Please Note: This document will be available in PDF format in the "My Electronic Documents" link on the home page once your order has been completed. Please make sure you have the latest version of Acrobat Reader. Click on the Acrobat Reader icon to check for the latest version, it’s FREE. To print a hardcopy of a PDF file correctly you must have a postscript printer. If you are not sure if your printer is a postscript printer please refer to your owner’s manual.



To reduce energy consumption in TMP pulping, ozone was tested in the mainline (directly in refiners) or in the reject line. The experiments were carried out at pilot plant scale (ozone in refiners) and at laboratory scale (reject treatment) with spruce chips. The application of ozone in the eye of the primary or secondary refiners modified the fibre separation mechanisms, reducing electrical energy consumption by 10 to 20%. It was demonstrated that ozone mainly oxidised the wood extractives and consequently modified the fibre surface chemistry and the final pulp quality. When used in refiners, ozone decomposition at high temperature and ozone reactions with fibre wall components were in conflict and reduced the ozone efficiency. Ozone treatment of TMP rejects seemed a very promising technology. An ozone charge of 1 to 2% on rejects gave an economy of 10 to 20% of energy, degradation of wood extractives and modification of lignin at the fibre surface. There introduction of these ozonated refined reject fibres in the TMP accepts improved the strengths and the peroxide bleachability of the final pulp. These effects could quite easily compensate the costs of ozone generation and use.