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Multiphase systems like slurries and emulsions have long been of great practical importance in everyday life. The stability of these systems is often dependent on shear conditions and other factors.

In the oil industry, crude oil represents a multiphase system that is extracted under high-pressure conditions. It contains paraffins and asphaltenes that can create numerous problems in production, transportation, and processing. The presence of various light and heavy hydrocarbons contributes to the complexity of these systems due to significant changes in their rheological behaviour at different temperatures. As temperature decreases, the solubility of heavy components is reduced, causing the “wax precipitation” that leads to transition from a Newtonian to a yield stress fluid, and consequently increases the danger of plug formation.

As a result, having a good understanding of the dynamic rheological properties is crucial for the proper design of processing, transport, and storage equipment. However, measurements of these materials’ physical properties are usually not possible using conventional measuring systems.

At Coanda, we use a specialized pressure cell, which is mounted on an Anton-Paar rheometer, to test such samples by employing unconventional measuring geometries. This system is used to simulate complex process conditions that require high pressure, to measure the rheological properties of samples that contain light components with low boiling points, and to prevent the sample evaporation during measurements.

The pressure cell system can be used in two ways, either with an external pressure source like high-pressure gas cylinder, or self-pressurization due to the presence of volatile components within the sample. It consists of a sealed cup that can sustain pressures as high as 150 bar. The rotating components inside the pressure cell are driven by a magnetic coupling, which is directly attached to the torque measurement system. It can deliver high shear rates while precisely measuring torque values over a range of temperatures and pressures.