Development and applications of industrial process analyzers

Contacts between users and suppliers is essential to ensure cost-effectiveness of process analyzers. Technical consideration of in-line, on-line and off-line measurements as well as analytical procedures are needed for selection of the most appropriate system. Quantitative performance specifications are often set too high, resulting in a sophisticated analyzer with excessive investment and maintenance costs. Process parameters such as time constant, sampling point and environmental conditions must be considered. Rules for decision-making are reviewed; autocorrelation, cross-correlation, controllability and information theory are useful in making efficient decisions on appropriate analyzers. Examples related to sulphur dioxide in stack gas scrubbers, chlorine in water supplies and sodium in boiler feed water are discussed.