Flowability and storage stability of highly active powder surfactant systems

Zhuo, Bingyu (2020). Flowability and storage stability of highly active powder surfactant systems. University of Birmingham. Ph.D.

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Abstract

Surfactant powder is a highly valuable product with many applications. It was felt desirable to enhance the physical stability of the powder so that it could be transported over long distances and to ensure its quality at end-use applications. Two different surfactant samples (with 33 wt% and 70 wt% surfactant content) were used in this research.
Firstly, the powders were characterised by their physical characteristics, mechanical properties, storage stability, and flowability. In addition, the effects of the physical characteristics on the flow behaviour of highly concentrated surfactant granules of different size ranges were studied. These studies showed that the surfactant powders were prone to picking up moisture and deliquescing under high humidity, poor in flow, and easily deformable.
Several materials (NaCl, KCl, Na2SO4, and EwBase) were used to coat the surfactant powders using a fluidised bed coater. The salt coating improved the flowability of the powder, but apart from Na2SO4, they all also reduced the deliquescence humidity of the powders. It was demonstrated that the Na2SO4 coating improved both the flowability and storage stability of the highly concentrated surfactant powder system. It was also shown that the enhanced flowability was related to the increase in the Heckel parameter when a salt coating of more than 70% surface coverage was achieved.
For surfactant powder, it was also found that reduction in particle size increased the flowability, until the van der Waal’s force became more significant and reduced the effect. The flowability and particles properties were fitted into a flowability prediction model established by Liu et al. (2008), and discrepancy was found between the data and the model. The model was thus further developed to seek a better understanding of the relationship between powder flowability and mechanical properties based on the Heckel parameter. It was demonstrated that improved flowability of the bulk powder was related to an increase in the Heckel parameter of the particles.
Overall, this report demonstrated a method in enhancing flowability of soft particle with salt coating, and also extends the understanding between powder’s flowability and its mechanical properties.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):