88-08: Polymer Blending for Dispersion and Deposit Control

A recurring problem of industrial cooling systems is deposition of particulates brought into the cooling system from outside the unit and those particulates generated within the system. Polymers and co-polymers have been applied with considerable success to specific types of particulates. The types of particulates can be quite varied depending on both the treatment and the nature of the water. Frequently, a single polymer or co-polymer is effective in one specific application and much less effective in another. One solution to this problem is the use of a variety of materials. Another is the use of blended polymers. The latter is often desirable for both cost of treatment and the effectiveness. This paper deals with methods of determining a blend of polymers for optimum adsorption and effectiveness for a particular solid phase found in a cooling system. The method measures the adsorption of polymer on a fixed amount of slurry of solid phase. The polymers used are chosen on the basis of the overall isotherm and the slope in the Henry's Law region of the isotherm. By using the isotherms for the individual polymers and the isotherm for the blend, the maximum adsorption can be obtained. The liquid for the slurries of material can be distilled water, system make-up, or cycled make-up. Several temperatures are run to give an indication of the effect of temperature on adsorption. Illustrations of the application of the technique and field application of the results are given.