Determinación del coeficiente de transferencia de masa en lechos de contacto de Carbonato de Calcio para la estabilización química de aguas corrosivas

Abstract

The objective of this work was to determine the mass transfer coefficient for the chemical stabilization of corrosive waters, using packed beds of CaCO3. It began with the construction of 4 beds, with transparent vinyl tubes, 1m high, and 3.175 cm of bed diameter and 40 cm of fill height, based on the parameters recommended by Castro (1992). Then, the packing material of the bed was selected, from commercial samples of CaCO3 from the companies LA ROCA S.A. and DISCAL, determining a purity of 95.56% of CaCO3. Subsequently, the material was sieved in 4 different granulometries, to be placed in the beds, each one characterized by particle diameter, porosity, density and interfacial area. The experimentation was carried out in two stages, first using synthetic water with IL <-0.5 and subsequently with groundwater from the well of the Cooperativa Nueva Aurora, Santo Domingo de los Tsáchilas. The corrosive water was fed to the beds, at 4 different rates of hydraulic application, for a period of 7 hours; the chemical stabilization control was carried out every 30 min, determining the pH, alkalinity, calcium, temperature, and electrical conductivity in the effluent. Finally, the chemical stabilization, I.L. = 0.13, was achieved with an application rate of 0.094 L / min, granulometry of 1.19 mm, experimentation time of 6 hours, and a mass transfer coefficient of KL of 0.870 kg / m2h. Stabilization with groundwater was not achieved due to the high concentration of iron that interferes with the process, so the application of packed beds at the end of the purification process is recommended.