ISSUE

At this facility, there were seven evaporators in series, and during the flow from evaporator 6 in the beginning of the process to the last evaporator 1A, fluid from the process liquid evaporated and the dry material content of the liquor increased from around 10 % to over 50 %. As a side effect of this process, the black liquor flowing through the series of evaporators caused calcium-based fouling issues especially in the evaporators at the end of the series, 1A and 1B.

• Fouling in the black liquor evaporators reduced energy and process efficiency and frequently reduced total pulp manufacturing capacity.
• In the worst case, the warmest evaporator (1A) needed two cleaning stops (1-5 days per stop) per month, whereas the 2nd warmest evaporator (1B) needed one cleaning stop per month.
• Constant “firefighting” and disturbance caused by the need to clean evaporators 120/365 days a year.

UP TO 120 DAYS PER YEAR

OF PRODUCTION INTERRUPTIONS 

RESULTS 

Pump current levels and flow rate were measured to see the effect of Altum's solution:

• Pump current levels became more even and stable.
• Energy efficiency improved by 10% per unit.
• Amount of washes decreased 75% for evaporator 1A and over
  85% for evaporator 1B.

OVER 10% PER UNIT 

IMPROVED ENERGY EFFICIENCY