ENERGY SAVING AND ENVIRONMENTAL PROTECTION AT RECIRCULATING COOLING WATER SYSTEMS

This paper deals with the problems of energy saving and environmental aspects (water consumption, drift emission, noise level) of cooling systems using mechanical draft wet cooling towers. Graphs have been developed to represent correlation between cooling performance, size of cooling towers, and fan power requirement for the most common operating range. Tracing of distinct cold water temperature is shown, below which reduction of fan power is advisable. Generalized charts are presented to provide values on cooling tower evaporation loss and make-up water demand

Prediction of long-term localized corrosion rates in a carbon steel cooling water system is enhanced by metagenome analysis

To predict variation of maximum localized penetration with exposure time, long-term localized corrosion was assessed in an emergency cooling water system composed of two carbon steel pipelines of 700 mm diameter transporting raw river water at flow velocities of 1 m/s and 0.1 m/s. Field tests, visual inspection, ultrasonic testing, BART testing, SEM-EDS and metagenomic analyses were performed to assess the progress of long-term corrosion and determine the influence of microbes in the corrosion process. High corrosion was linked to sulphate reducing bacteria and potentially to methanogenic archaea in the low-velocity pipeline, while moderate corrosion was linked to non-sulphate reducing bacteria in the higher velocity pipeline. Using historical and literature data available as well as our own test results, an empirical model was developed to predict Maximum Localized Penetration change over time to be applied in the ageing management of cooling water systems. Molecular Microbiological Methods in combination with traditional techniques are useful tools in the ageing management of pipelines. By applying the empirical model developed and the approach presented, unexpected through-wall leaking can be avoided, thus, saving costs and assets