Improving the performance of the 120 M3 continuous low grade pan at Farleigh

A new 120 cubic metre continuous low grade vacuum pan was installed at Farleigh Mill for the start of the 1987 season. The throughput aspects of the pan have proved to be greater than originally specified by a conservatively estimated 15 per cent. The massecuite produced by the pan exhibits good exhaustion characteristics with large purity differences between massecuite and mother liquor and high impurity/water ratios. Some operational problems, particularly with the formation of fine grain in the pan were experienced during the 1987 season and this paper describes the changes to the control and operational procedures which have been undertaken to overcome these problems. The paper also discusses crust formation within the pan. Performance data on the continuous pan and the low grade fugal station are also presented.