Inorganic Scale in ECF Bleach Plants: Rapid Test Method for Prediction and Control, 2001 Pulping Conference Proceedings

C. Greer, S. Shevchenko, P. Duggirala--Conversion to ECF bleaching has resulted in increased scale deposit problems for many kraft mills. Scale accumulation on washer wires and screens, in stock and liquor transfer lines, on pH and brightness probes, and in pumps and vats can cause severe bleach plant operational difficulties. Strategically placed coupons have traditionally been used to monitor scale accumulation. However, scaling tendencies inferred from coupon deposit weights often cannot provide useful, proactive information on a timely basis. A new test method has been developed which employs a proprietary, patent pending, scale monitoring device. The Scale Rate Monitor rapidly and accurately measures the calcium carbonate and calcium oxalate scaling potential of bleach plant process streams. The Scale Rate Monitor has been used at several mills to quantify the effects of process changes and/or chemical antiscalant programs on scale deposit potential.