Petroleum & Coal ISSN 1337-7027 Available online at www.vurup.sk/petroleum-coal Petroleum & Coal 55 (1) 26-30, 2013 USING DEMULSIFIERS FOR PHASE BREAKING OF WATER/OIL EMULSION Amir Mosayebi, Reza Abedini* Department of Petroleum Engineering, Mahallat Branch, Islamic Azad University, Mahallat, Iran, *Corresponding author e-mail: reza_abedini20@yahoo.com (R .Abedini) Received October 1, 2012, Accepted January 30, 2013 Abstract Demulsification (emulsion breaking) is necessary in many practical applications as the petroleum industry and waste water treatment in environmental technology. The emulsion stability results from the presence of interfacial barrier preventing coalescence of the dispersed water droplets. The most effective method to overcome the problem is to demulsify the crude by using demulsifiers. The demulsifiers will destabilize the interfacial film between the droplets. Demulsifiers with amine and polymeric groups were used for breaking of water in crude oil emulsion, in this study. The relative rate of water separation were determined via breaker tests. The polymeric group demulsifier had better performance on breaking emulsion than amine group demulsifiers. Keywords: demulsifier; interfacial film; emulsion; droplet; stabilize. 1. Introduction Water-in-oil emulsion is formed during the production of crude oil, which is often accompanied with water. The stability of the emulsion is ranging from a few minutes to years depending on the nature of the crude oil and to some extent the nature of water [1] .A recent report has suggested that an equivalent volume of water accompanied the daily production of some 60 million barrels of crude oil [2] . Under the production conditions, a proportion of this water can become intimately dispersed throughout the crude oil as small droplets. The natural petroleum emulsion resulting from the secondary production consists of crude oil as dispersion medium and brine as dispersed phase, normally stabilized by natural chemicals such as asphaltenes, resins, solid such as clays and waxes [1] . For asphaltenes in particular, the presence of hetero- atoms in the essentially aromatic structure imparts amphiphilic characteristics [3] . Emulsions are undesirable because the volume of dispersed water occupies space in the processing equipment and pipelines, increased operating and capital costs. Moreover, the characteristics and physical properties of oil change significantly upon emulsification. The density of emulsion can increase from 800 kg/m3 for the original oil to 1030 kg/m 3 for the emulsion. The most significant change is observed in viscosity, which typically increases from a few mPa.s or less to about 1000 mPa.s [4] . Chemical methods are the most common method of emulsion resolution in both oil field and refinery. The application of chemicals designed to neutralize the effects of emulsifying agents have great advantages of being able to break an interfacial film effectively; without the addition of new equipments or modifications of the existing equipment. 2. Materials and Methods The crude oil applied as model in this study was obtained from the Refinery of Tehran. Specifications and some physical and chemical properties of this crude oil are listed in table 1. There are wide ranges of demulsifiers that can be used in demulsification of crude oil emulsions. From the literature study, the demulsifiers used in this paper are shown in Table 2. In this study, three demulsifiers, amine groups, polymeric and alcohol were used for water in crude oil emulsions demulsifications. A 500 mL gratuated cylindrical glass was used as sample container.