FLOW-INJECTION ANALYSIS FOR POWER-PLANTS - EVALUATION OF DETECTORS FOR THE DETERMINATION OF CONTROL PARAMETERS IN CONDITIONED WATER STEAM CYCLES

Flow-injection methods are described for monitoring water in power-plant cycles. The parameters considered are pH (in the range 5.5-9.5), using a flat-headed combined electrode, ammonia (0.2-3 mg N l-1), using Nessler, Berthelot and gas-diffusion methods, hydrazine (0.025-0.3 mg l-1), using the dimethylamino-4-benzaldehyde method, copper (0.02-0.2 mg l-1), using bathocuproin and methods based on ion-selective electrodes, iron (0.01-10 mg l-1), using phenanthroline, ferrozine and biamperometric methods, and silicon (0.02-0.1 mg l-1), using the heteropoly blue complex, with two different types of reducing agent [tin(II) chloride and ascorbic acid]. The parameters considered were precision, analysis frequency and application range. The results obtained showed that flow-injection methods perform well in terms of sensitivity and analysis frequency and suggested the possibility of transferring this methodology to analytical systems in power plants. © 1990.