Performance of wire mesh mist eliminator

An experimental study was made to measure the performance of wire mesh mist eliminator as a function of broad ranges of operating and design condition s. The experiments were carried out in an industrial scale layered type dem ister pad made of 316 L stainless steel wires. The demister performance was evaluated by droplet separation efficiency, vapor pressure drop of wet dem ister, and flooding and loading velocities. These variables were measured a s a function of vapor velocity (0.98-7.5 m/s), packing density (80.317-208. 16 kg/m(3)), pad thickness (100-200 cm), wire diameter (0.2-0.32 mm), and d iameter of captured droplets (1-5 mm). All the measurement results lie in r anges where, in practice, the wire mesh mist eliminator predominates. The e xperimental results indicate that the separation efficiency increases with both the maximum diameter of capture water droplets and the vapor velocity and with the decrease of wire diameter. The pressure drop for the dry demis ter is relatively low and depends only on the vapor velocity. The pressure drop increases linearly up to the loading point, thereafter; the rate of in crease is larger. Beyond the flooding point, the increase rate is significa nt even for the slightest rise in the vapor velocity. The flooding velocity diminishes with the beef-up of the packing density and with the decrease o f the wire diameter. Three empirical correlations were developed as a funct ion of the design and operating parameters for the separation efficiency, p ressure drop for the wet demister in the loading range, and the flooding an d loading velocities. These correlations are sufficiently accurate for prac tical calculations and demister design. The temperature depression correspo nding to the pressure drop in a wire mesh mist eliminator systems installed in a typical multi stage flash desalination plant was estimated from the d eveloped correlation. A good agreement was obtained between the design valu es and the correlation predictions. (C) 2000 Elsevier Science S.A. All righ ts reserved.