(183ak) Molecular Modifiers Reveal Unique Inhibition and Dissolution Mechanisms in Barite Scale

Authors: 
Sosa, R. D., University of Houston
Geng, X., University of Houston
Palmer, J. C., University of Houston
Reynolds, M. A., Shell Exploration and Production Company
Conrad, J. C., University of Houston
Rimer, J. D., University of Houston
Adsorption and subsequent precipitation of sparingly soluble compounds during oil and gas production, water treatment, and manufacturing processes may severely damage equipment and cause reduction or loss of finished product, thus posing serious challenges for these industries. Designing effective biodegradable chemical treatments to reduce or eliminate scale formation requires an understanding of the molecular-scale interactions of chemical additives in supersaturated and undersaturated environments. Here we apply a unique approach to design and test environmentally friendly chemical treatments for scale formation using a combination of surface science techniques, microfluidic technology, and molecular modeling. Crystallization can be inhibited in highly supersaturated solutions and dissolution can be promoted in undersaturated media using dilute quantities of modifiers. The precise effect of hydrodynamics, which alters modifier-crystal interactions, on inhibitor and dissolver efficacy remains elusive. Our studies focus on barium sulfate (barite), a highly insoluble and common scaling mineral. In this presentation we will describe a microfluidic platform that is used to perform multiple bulk crystallization assays simultaneously and capture real time crystal inhibition and dissolution in the presence of molecular additives. Using in situ scanning probe microscopy, we explore the interfacial interactions between the modifiers and different surfaces of barite over a range of undersaturated and supersaturated conditions to elucidate the role of these putative inhibitors/dissolvers during the growth and dissolution phases. Concurrently, we use molecular modeling of inhibitor adsorption of barite surfaces to probe the interactions that govern modifier-crystal specificity and efficacy. Collectively, these studies generate new understanding of the mechanisms of crystal growth modifiers that can be applied to the design of improved scale treatments.