title: Effect of ultrasonic frequency on separation of water from heavy crude oil emulsion using ultrasonic baths.
abstract: In this work, a comprehensive study was performed for the evaluation of ultrasound (US) frequency for demulsification of crude oil emulsions. Experiments were performed using ultrasonic baths operating at the following frequencies: 25, 35, 45, 130, 582, 862 and 1146kHz. Synthetic water-in-oil emulsions with 12%, 35% and 50% of water and medians of droplet size distribution (DSD, D(0.5)) of 5, 10 and 25μm were prepared using a heavy crude oil (API density of 19). Crude oil demulsification was achieved at frequencies in the range of 25-45kHz for all tested emulsions. When frequencies higher than 45kHz were applied, no changes in the characteristics of the crude oil emulsions were observed. Demulsification efficiencies of about 65% were achieved at a frequency of 45kHz after 15min of US application (emulsions with original water content of 50% and D(0.5)=10μm). An important aspect is that no addition of chemical demulsifiers was performed, and the demulsification efficiency was considered high, taking into account that the results were obtained using a non-conventional crude oil. Contrary to the normal application of low-frequency US that has been used for emulsification, the proposed approach seems to be a promising technology for water removal from crude oil emulsions.
authors.affiliation: Empresa Brasileira de Pesquisa Agropecuária, Embrapa Suínos e Aves, 89700-991 Concórdia, SC, Brazil.
authors.forename: Fabiane G
authors.initials: FG
authors.lastname: Antes
authors.affiliation: Empresa Brasileira de Pesquisa Agropecuária, Embrapa Gado de Corte, 79106-550 Campo Grande, MS, Brazil.
authors.forename: Liange O
authors.initials: LO
authors.lastname: Diehl
authors.affiliation: Departamento de Química Inorgânica, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS, Brazil.
authors.forename: Juliana S F
authors.initials: JS
authors.lastname: Pereira
authors.affiliation: Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello - CENPES/PETROBRAS, 21941-915 Rio de Janeiro, RJ, Brazil.
authors.forename: Regina C L
authors.initials: RC
authors.lastname: Guimarães
authors.affiliation: Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello - CENPES/PETROBRAS, 21941-915 Rio de Janeiro, RJ, Brazil.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Guarnieri
authors.affiliation: Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello - CENPES/PETROBRAS, 21941-915 Rio de Janeiro, RJ, Brazil.
authors.forename: Bianca M S
authors.initials: BM
authors.lastname: Ferreira
authors.affiliation: Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil. Electronic address: ericommf@gmail.com.
authors.forename: Erico M M
authors.initials: EM
authors.lastname: Flores
keywords: Crude oil; Demulsification; Emulsion; Low frequency ultrasound; Ultrasound; Water removal