ABSTRACT
Enhanced oil recovery (EOR) by chemical methods, such as injection of surfactants and polymers, increases the efficiency of extracting petroleum. However, after permeating the reservoir, these products remain in the produced water and hamper its treatment, including the efficiency reduction of the flocculants normally used for this purpose. In this work, oil-in-water (O/W) microemulsions were prepared according to ternary phase diagrams, with two oil phases, solbrax and kerosene, extracted from oil fractions, and two ethoxylated nonylphenol surfactants with 8 and 9.5 ethylene oxide units (NP80 and NP95), respectively, along with brine. The objective was to evaluate the effects of these components' presence in the microemulsions on the treatment of produced water. The microemulsified systems were characterized regarding viscosity, size of the dispersed droplets and stability. The results showed that the microemulsions containing the most polar surfactant (NP95) caused greater stabilization of the O/W emulsion (produced water). However, there also was a synergistic effect when using a commercial flocculant along with the microemulsion based on NP80, diminishing the residual oil content in the produced water.
ABSTRACT
The aim of this study was to investigate the application of oil in water (O/W) nanoemulsion as solvent in the extraction step for determination of oil content in oily water, measured using a UV visible spectrophotometer (UV-vis) and a total organic carbon (TOC) analyzer. The optical micrographs and distribution size curves showed that the use of a small amount of nanoemulsion was capable of transforming the oily water in a colloidal dispersion that can be read in the UV-vis and TOC-VCHS devices. The oil content results obtained showed great accuracy between the measurements, with very low average standard deviation (â¼5%) for both UV-vis and TOC-VCHS. The new methods suggested in this work are very promising, since they allow simple, quick and accurate analyses, and especially require a lower volume of solvent (less than 1%) compared to those used in conventional analytic methods.