Measurement of water concentration in oil/water dispersions with a circular single-electrode capacitance probe

A new measurement method, called SeCaP, has been used to measure the water content in oil/water dispersions. The measuring principle is based on an oscillator working at approximately 20 MHz. The dielectric property of the medium adjacent to one single free electrode affects the frequency of the oscillator. The dispersion was produced by means of recirculation through a colloid mill. The concentration of water was first increased from zero to approximately 70%. Then, it was reduced from 100% to approximately 45%. The probe signal correlates very well with the water concentration in the dispersion, especially for the oil continuous case with a correlation coefficient of 0.9998. The instrument represents a new approach of measuring the water content in process streams in, for example, oil production facilities, where it is important to have reliable information on the amount of water that is flowing in the production tubing.