Test center: Let them test filter cake
A supplier's solids test center helps a chemical company choose the right vertical mixer-dryer for removing solvent from a centrifuge filter cake.
A specialty chemicals company located in the Midwest produces a powder additive used in the paper industry. To make the additive, the company dries a centrifuge filter cake containing about 15 percent toluene (a solvent) to less than 0.1 percent toluene. In the past, the company used a 3,000-liter-capacity conical screw (Nauta) mixer-dryer to remove the excess solvent from the filter cake. However, as the filter cake dries it becomes very dense, increasing the torque required to move the mixer-dryer's rotating orbiting screw through the filter cake. Because of this, the screw would fail after about 6 to 12 months of use and need to be replaced, which increased production downtime as well as maintenance and production costs. While searching for a solution to this problem, the company worked with a Germany-based vertical mixer-dryer supplier, conducting material and equipment tests at the supplier's European test center.