*Article* **Water Content Monitoring in Water-in-Oil Emulsions Using a Piezoceramic Sensor**

**Carlos A. B. Reyna 1, Ediguer E. Franco 2, Alberto L. Durán 1, Luiz O. V. Pereira 3, Marcos S. G. Tsuzuki <sup>1</sup> and Flávio Buiochi 1,\***


**Abstract:** This work deals with a transmission-reception ultrasonic technique for the real-time estimation of the water content in water-in-crude oil emulsions. The working principle is the measurement of the propagation velocity, using two in-house manufactured transducers designed for water coupling, with a central frequency of about 3 MHz. Water-in-crude oil emulsions with a water volume concentration from 0% to 40% were generated by mechanical emulsification. Tests were carried out at three temperatures. The results showed that the propagation velocity is a sensitive parameter that is able to determine the water content, allowing for differentiating the concentrations of up to 40% of water. The main motivation is the development of techniques for non-invasive and real-time monitoring of the water content of emulsions in petrochemical processes.

**Keywords:** water-in-crude oil emulsion; water content; ultrasound; propagation velocity
