A utilização da eletroflotação como alternativa na remoção de óleos emulsificados em efluentes da indústria de petróleo.

Abstract

The development of new treatment technologies for petroleum industry effluent with high salinity has been a challenge due to the increase of oil production in Brazil. High salinity and the great volumes normally involved prevent the use of biological processes. This work intends to evaluate in bench scale, the separation of emulsified petroleum in water using the electroflotation technique as alternative to the gravity separation method used in the primary oily water treatment in maritime platforms, as a process to improve the quality of the discarded effluent in off-shore platforms. A rectangular configuration electroflotation cell was designed and constructed in acrylic, a stainless steel expanded cathode and a DSA (dimensionally stable anode) of nominal composition Ti/Ruo,34Ti0,6602 had been used sa electrodic material. The effects of some operating variables investigated in the process were electric current, initial oil concentration, flocculant agent concentration and salinity. A comparative study with perforated iron electrode used as sacrificial anode also was carried out. The experiments had been carried through with the use of the experimental planning of two types: in the first phase a factorial planning 24, with three repetitions in the central point, to investigate the process with the cell in batch mode, the second stage a planning of type 2" with the cell operating in continuous mode. Statistical calculations were done by using STATISTIC A 6.0 software. The maximum oil separation was 98.76% obtained at optimum conditions such as: 0.3 A, 4.0 ppm of flocculant agent, 3.38 wt % of NaCl and 20 min of electrolysis. With electric energy consumption of 0.167 kWh/m3. The effluent once treated yielded an effluent with (TOG) less than 20 ppm. The initial oil concentration that supplied one better removal was 1020ppm. The results indicate that the energy consumption in electroflotation technique decrease significantly in presence of NaCl. This makes electroflotation technique a useful method in removing oil emulsions formed after accidents of oil spills in seawater.