Study On The Hydrodynamic Performance And Mass Transfer Efficiency Of Three-dimensional Spary Tray

As the core facilities of the mass transfer process, the tower equipment plays avery important role in the separation and purification process. It has a great impact onthe raw material consumption, product yield and quality, production capacity of theprocess. The successful development and application of three-dimensional tray injectsnew life into development of plate tower. It is the superior performance of masstransfer and energy advantages that attract researchers to conduct research and itsdevelopment.In this paper, two three-dimensional spary trays (TDST) were designedinventively, named Tray30and Tray45respectly. The influence of operatingconditions on pressure drop was investigated by experiment with air-water medium.The influence of operating conditions and solution conditions on plate efficiency wasstudyed by air stripping of ammonia.The results showed that, in the range of experimental operation, the dry platepressure drop and gas kinetic energy factor (F0) were related in quadratic function.With the increase of F0, pressure drop of Tray45increased slowly before7m·s-1·(kg·m-3)1/2, then increased sharply, while Tray30grew up uniformly. With theincrease of liquid flow rate, pressure drop of both Tray30and Tray45increasedlinearly. Compared with the traditional trays, TDST had lower pressure drop, lessthan100Pa for Tray45and150Pa for Tray30at a gas velocity of2.0m·s-1and liquidflow rate of16m3·h-1·m-2. Gas velocity of liquid blocking point and flooding velocitywere gotten by the analysis of linear regression coefficient of pressure drop on theliquid flow rate, and draw the loading chart.The plate efficiency presented a trend of first increase then decrease with theincrease of liquid flow rate. With the increase of gas velocity, although the gas-liquidcontact time shortened, the plate efficiency increased slightly after a decrease as theoperationing state grew into the spray regime which is better for mass transfer in highgas velocity. With the increase of ammonia concentration in influent, plate efficiencyof both Tray45and Tray30increased first then decreased. As the free ammoniaconcentration increased with the raise of pH, plate efficiency of Tray45increasedgradually. When the other conditions were fixed, the pH of the effluent was positively related to the initial pH of influent linearly. Compared with Tray30and plastic Pallring packing layer by pressure drop per unit mass of the nitrogen, Tray45gained anadvantage in the energy saving.In the air stripping of ammonia nitrogen by Tray45and Tray30, the nitrogenremoval efficiency increased with the increase of gas velocity, decreased with theincrease of liquid flow rate, increased with the increase of the initial pH of influent,increased first then decreased with the increase of ammonia concentration in influent.