In pine Kraft softwood mills tall oil soap is a valuable by-product as well as a toxin in the wastewater treatment system. Thus it is necessary to properly manage foam and soap within the mill. Managing this issue requires a number of steps including the handling and deaeration of foam, separation of soap from liquor, and the separation of liquor from soap. Lundberg can provide a complete system to manage and collect soap within your black liquor system. Our systems include Skumslakers to break the foam, concentrators to further deaerate the soap, floating soap skimmers to collect the soap and soap separators to remove black liquor from the collected soap.
Soap in black liquor is at its lowest solubility midway through an evaporator set. Here the soap is allowed to decant from the liquor in a soap skim tank with a continuous rake mechanism skimming the soap from the top. Depending upon the care taken in a number of the recovery steps above, the separated soap may contain a large amount of black liquor. The black liquor not only costs money to ship to the tall oil processing plant but also represents a handling issue at the tall oil processing plant. Lundberg‘s soap separator is designed to reduce the liquor content of the soap to below 5%.