Resumo:
The presence of produced water in association with oil represents one of the most significant
challenges faced by the oil and gas industry. Although conventional physical methods, such as
heating and the application of electric fields, are effective in promoting oil dehydration, the
high operational costs associated with intensive energy consumption justify the use of
demulsifiers. These chemical agents work synergistically with physical processes, reducing
energy consumption. However, the effectiveness of these additives depends on specific
conditions, such as component ratios, process temperature, and formulation concentration. The
determination of these optimal conditions is traditionally conducted through trial and error
experimentation, often leading to costly and time-consuming results. To address these
limitations, the present study employs a Design of Experiments (DOE) approach as a
methodological tool for the systematic design and execution of demulsification tests,
facilitating a more efficient and cost-effective process analysis. Two sequential experimental
designs were implemented. The first involved a mixture design aimed at determining the
optimal proportions of formulation components, which included two commercial demulsifiers:
an EO/PO copolymer (ethylene oxide/propylene oxide) and alkoxylated resin, with xylene used
as a diluent. Subsequently, additional demulsification tests were designed based on a 2² factorial
design to determine the optimal temperature and concentration conditions for maximizing
demulsification efficiency. Efficiency was assessed using the Bottle Test, in which the mixture
design tests were conducted under fixed operational conditions recommended by the reagent
suppliers, utilizing 300 ppm of demulsifiers at a temperature of 75 ºC. For factorial design,
operational conditions were evaluated within temperature ranges of 55 ºC to 75 ºC and
demulsifier concentrations from 300 ppm to 900 ppm. Based on the results obtained from the
Bottle Test, two statistically significant mathematical models were developed. The highest
water separation efficiency (91.02%) was achieved with Formulation J, which consisted of 67%
alkoxylated resin, 17% EO/PO copolymer, and 17% xylene. In the 2² factorial design, the
optimal operational conditions for this formulation were identified at a concentration of 300
ppm and a temperature of 75 ºC, resulting in a water separation efficiency of 91.34%.
