Lundberg provides black liquor concentrator systems to solids in excess of 80%. These systems may be stand-alone, integrated with a multiple effect evaporator system or integrated with a pre-evaporation system.
Lundberg offers flooded forced circulation (FFC), falling film or mixed falling film, and flooded forced circulation technologies depending upon our customer’s needs. Integrating the concentrator into an evaporator system requires a careful balance between energy costs and capital cost. In the concentrator, the boiling point rise of the liquor becomes an important factor in equipment sizing and the ability to utilize the vapor at a given location in the evaporator system. Integration of a concentrator into an existing evaporator set complicates things even further. Lundberg engineers factor all of these issues into the design of the concentrator system to provide the mill with the most cost effective and economical system possible.
Lundberg is unique in offering flooded forced circulation concentrator technology to the paper industry. This technology utilizes forced liquor circulation through the tube side of a heater with the liquor under a backpressure to prevent boiling. The superheated liquor is discharged into a flash tank (vapor head) where it is allowed to expand and equalize at a lower temperature. The change in temperature results in evaporation of water from the liquor. This process is particularly suited to liquors with a high scaling tendency since there is no change in composition of the liquor on the heating surface. Further, because the liquor is forced through the tubes, the tube bundle is flooded and there is no concern about liquor distribution.