Pulp & Paper
Case:
FOULING PREVENTION IN RED LIQUOR EVAPORATORS
PULP MILL | SOUTH AFRICA
By preventing fouling in red liquor evaporators, energy efficiency was improved by over 50% and operational time increased by 25%.
ISSUE
The customer has three effect evaporators in series. The evaporators use steam to evaporate water from red liquor to increase dry solid content to over 50%. The steam circulates from the first effect to second and fourth, and finally in the condenser. The evaporators get fouled by calcium-based fouling, and this causes issues in the evaporators’ tubes.
SOLUTION
The fouling prevention solution uses a high-power ultrasonic field directed at the red liquor flowing through the evaporator pipes. This ultrasonic field induces sonocrystallization, altering the crystal structure of calcium-based fouling and preventing it from attaching to the evaporator’s tubular structure.
RESULTS
Ultrasonic treatment of red liquor has been shown to increase the period between washes by more than 60% and the energy efficiency improvement in evaporators by more than 50%.
Additionally, the evaporation rate increased by more than 6%, and the operational time by 25%.