EVALUATION OF CONDUCTIVITY SENSORS FOR ALKALI DETERMINATION IN KRAFT WHITE LIQUORS

A study was initiated and sponsored by the Measurement Technology Comm ittee of the American Forest and Paper Association (formerly API) to e valuate three types of commercially available conductivity sensors and transmitters. The first part of this study, described here, is for wh ite liquor applications. The three sensors included a four-electrode t ype, an insertion electrodeless type, and a flow-through electrodeless type, All three sensors were tested under the same conditions in a te st loop. The responses to changes in flow, temperature, and concentrat ion of laboratory white liquors were measured. Good correlations were established between conductivity and alkali concentration for all thre e sensors. The effects of other chemical ions also were measured. Ther e was no effect from velocity changes in the range studied. There were some differences in temperature compensation functions among the inst ruments.