Caracterização e recuperação de óleo de borra oleosa da indústria de petróleo por extração e decantação

Abstract

Currently, the oily sludge generated by the petroleum industry, from different primary processing units, such as: production separators, API boxes, produced water flotators, storage tanks or accidental spills, are then dispposed in dikes, ditches, or stored for later use in landfills. The sludge has a paste-like composition, in the form of emulsions, made up of sand, oil, water, and different chemical products used in the process of production. In general, there is no recovery of the oil present in the sludge, which generates great environmental and financial losses. The literature shows diverse techniques for the treatment/final disposal of sludge, as follow: centrifugation, solvent extraction, incineration or controlled combustion, co-processing in cement factories, incorporation into ceramic materials, encapsulation for inertization of the sludge, biological degradation in landfarming, and bioremediation, among others. This work discusses the characterization of oily sludge and the development of a technique for recuperation the oil present in the sludge, based on a stage of the extraction process (with condensed natural gas – C5 +), which is then followed by the separation of these elements using gravitational and centrifugal force fields, adding value to the once-discarded sludge. The samples of oily sludges were analyzed based on their content of basic sediment and water (BSW), total solids, salinity, drop size distribution, levels of asphaltenes and resins, and levels oil and grease. The samples were then treated with a surfactant agent (Dissolvan) and mixed with C5 +. After the mixing of the constituents, they were separated by two different methods: centrifugal or gravitational processing. An average product containing 60% BSW, a salinity level of 31734 mg/L, a density of 0,9794 g/cm³, and an °API of 8,29 was found. The efficiencies of the separation were measured in terms of the recovery of oil, reaching average values of 84,0 and 59,0% for the centrifugal and gravitational processes, respectively. These reults are similar to those found in the literature and in the petroleum industry.