Estudo de um reator para eletroflotação de águas residuais da indústria do petróleo visando sua reutilização.

Abstract

The aim in this work is to study the performance of an “air lift” electrochemical reactor, in semipilot scale, which was used in the eletroflotation process applied in the oils and greases separation in oil-water emulsions produced in the petroleum industry. With this study has been developed a treatment system of produced water in the petrochemical industry aiming to improve the technical, economic and environmental aspects. For that, the following studies were performed: generation, characterization and behavior of bubbles of H2 and Cl2; mass transfer and modeling of the reactor, and performance of the reactor and of the eletroflotation process in the treatment of synthetic and real oil-water emulsions. The experiments with synthetic emulsion were performed in laboratory, and to real emulsion, in Effluents Treatment Station of the Unit of Treatment and Fluids Processing of PETROBRAS S.A Company (ETE/UTPF/UN-RNCE/PETROBRAS) in “Guamaré - RN”. According to the results, the diameter, velocity, area, volume and radius of Sauter to the bubbles of H2 and Cl2 have been reduced by the concentration of NaCl and little influenced by the electrical current density. The mass transfer rate in the reactor has been increased greatly by the gas bubbles production. The oil removal rate in synthetic emulsion varied from 55.80 to 90.91% and was affected mainly by the electrical current density and by the concentration of NaCl. The energy consumption varied from 0.5185 to 1.5678 kWh m-3 and was influenced by the current density and volumetric flow. For the real emulsion, the removal rate varied between 76.92 and 86.96% and the energy consumption from 0.4194 to 2.4138 kWh m-3. The studied variables present phenomenological effects similar to synthetic and real emulsions, but the reactor presented a best performance with the real emulsion. To the best experimental condition ( = 300.0 m A e j -2, = 0.0450 m v Q 3 h-1 and H = 0.5750 m), with 1000 mg L-1 of NaCl, was obtained a removal rate of 86.96%, with a reduction from 69.0 mg L-1 to 9.0 mg L-1 of the oil concentration and an energy consumption from 1.8467 kWhm-3. The kinetics of oil removal was best represented by the solution of a model of second order. The oil concentration of the treated effluent in Effluents Treatment Station of PETROBRAS S.A. Company was reduced about 79.00%, corresponding to a reduction from 14.0 mg L-1 to 3.0 mg L-1, in 120.0 min of electrolysis.