Partial Borate Autocausticising Technology Mill Trial Experiences, 2005 Engineering, Pulping & Environmental Conference

A trial of Partial Borate Autocausticising (PBAC) technology was completed at Carter Holt Harvey’s Kinleith kraft pulpmill during 2004. The trial aimed to demonstrate the technology was compatible with mill operation and to characterise the benefits in liquor circuit de-bottlenecking. The trial confirmed PBAC technology was compatible with the mill operation. The presence of borate in the liquor circuit posed no threat to normal operations and did not have any affect on finished pulp or paper products.

PBAC reactions produced significant quantities of caustic in green liquor, prior to recausticising. On average an additional 34 t/day of caustic was present in green liquor during the trial period when compared to the baseline period. In addition, lime demand for causticising decreased by an average of 24 t/day. This meant that every tonne of borate added to the liquor circuit, on average reduced lime demand for white liquor production by 13 t/day.