(680c) Comparative Study of Sugar Powder Consistency Using an FT4 Powder Rheometer and Drag Force Flow (DFF) Sensor

The rheological properties of seven common sugar powders were characterized using an FT4 Powder Rheometer^® and a Lenterra Drag Force Flow (DFF) sensor. The data generated by both the FT4 Powder Rheometer and DFF sensor reflect mechanical resistance of the powders to forced flow. During dynamic flow FT4 analysis, a precise volume of powder is subjected to the flow pattern of a rotating blade that moves downward through the powder bed. Measurements of the torque and force applied to the blade are combined to calculate Basic Flowability Energy (BFE), quantifying the powder’s resistance to the blade motion. [1]

The recently developed DFF sensing technology provides instantaneous readings of the force exerted by particulate flow to a narrow pin immersed within process equipment. The output of the DFF sensor quantifies the drag force, which is a function of material properties such as particle size, morphology and adhesion [2]. The DFF sensor is primarily intended for real-time, in-line process monitoring where the probe is installed within processing equipment. The technology has shown to be a valuable Process Analytical Technology (PAT) tool for High Shear Wet Granulation (HSWG) [3]. For this study, an DFF test station was assembled, where a probe was installed into a laboratory scale mixer with a bottom-mounted impeller.

DFF sensor measurements have previously been compared to FT4 BFE data during HSWG process cycles [4]. The study confirmed that both the in-line DFF sensor and at-line FT4 similarly responded to changes in wet mass densification during the granulation cycle for the majority of blends. This research also highlighted some differences between the measurement trends for formulations with higher binder content. These differences are deemed to be related to wet mass attrition during the delay between the DFF and FT4 measurements, respectively. While DFF sensor measured the flow force in real time inside the granulator, it took between 7 to 12 minutes to discharge the powder from the granulator and run an FT4 test. Even this relatively small time delay may have caused the wet mass properties to change between analysis techniques.