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Interpreting Amistco TEX-MESH™ Performance Curves
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TEX-MESH efficiency curves express collection efficiency of a 6 inch pad as a function of droplet diameter for a vapor velocity corresponding to a system load factor* of 0.35 ft/sec. To estimate overall collection efficiency, the pad thickness, system load factor, and droplet-size-distribution must be factored into the estimate.
The effects of pad thickness and system load factor are based on proprietary correlations. Generally, efficiency diminishes significantly for pad thickness less than 4 inches and system load factor less than 0.1 ft/sec. The D99 point is the droplet diameter at which the efficiency curve crosses the 99% line. If the entrained liquid in a gas stream is composed entirely of droplets larger than the D99 diameter, then the overall entrainment removal efficiency of the mist eliminator, properly sized, will be greater than 99.9%. In most design problems concerning entrained droplets, the actual droplet-size-distribution is based on field experience. Entrainment arising from mechanical processes (boiling, two phase processes, seal leakage, surface condensation, etc.) typically produces droplets larger than 20 microns. Entrainment arising from chemical processes (reaction, endogenous condensation, etc.) typically produces droplets in the submicron range.
TEX-MESH performance curves are based on data for an up flow air/water system. Because of differences in the physical properties (densities, viscosities, and surface tension), the actual performance of a given system may be somewhat different from the performance curves. In general, however, most systems are analogous in performance to an air/water system.
Mist pads for horizontal flow are typically designed for higher velocity (K factor 0.5 ft/sec instead of 0.35 ft/sec for up flow). The resulting collection efficiency will be somewhat higher. Furthermore, cross flow drainage shifts the reentrainment (flood) curve upward. Consequently, the entrained liquid flux limit (gpm/sqft) is higher than up flow.
Vapor Velocity x (Vapor density)^1/2
*System Load Factor=__________________________
(Liquid density-Vapor density)^1/2
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