Operation of a six-effect evaporator station with a deficit in the vapour balance

Abstract

During the operation of a six-effect evaporator station the vapour balance is subject of interfering incidents such as changing technological states of the process or surrounding conditions (ambient temperature e.g.) This article analyses and compares possible methods of managing the operation i.e. reaction to these incidents. In particular, methods of stabilizing the vapour balance by supplying water or thin juice to individual effects of the evaporator station and bypassing the vapours between effects are compared. The best way of reacting to the overload of the evaporator station seems to be the bypass of vapour from an effect of higher parameters to an effect of lower parameters. This method creates a much faster reaction of the evaporator station to excessive bleeding of vapour than supply of water or thin juice, which need to mix with the juice in the vessels. Feeding water to the thin juice tank or to one of the effects of the evaporator station to compensate excessive vapour consumption can be an acceptable solution in case of prolonged increase in vapour consumption from the evaporator station due to e.g. a significant decrease in ambient temperature.