Contactless Asphaltene Detection Using an Active Planar Microwave Resonator Sensor

In this paper, a noncontact real time method for asphaltene concentration measurement and precipitation detection is presented. An active high sensitivity microwave resonator sensor is utilized to monitor asphaltene particles and its complex permittivity at 1.2 GHz. The sensor utilizes a microstrip microwave resonator with an active feedback loop to compensate for the environmental loss and to enhance the quality factor of the sensor by several orders of magnitude (>10K). The sensor is utilized to directly measure the concentration of the liquid through monitoring its complex permittivity. It is also illustrated that time-based measurements can be used to increase the accuracy by providing two independent data sets, i.e., concentration and time constant. Next, heptane is mixed with different concentrations of asphaltene and monitored in real time. The results demonstrate the capability of noncontact measurement of the precipitation process at different asphaltene concentrations. The findings exhibit a substantial step toward a low-cost, real-time, and noncontact chemical monitoring device