Characterization of Nanocolloidal Silica Formation of Untreated and Treated Simulated Geothermal Brine Through Various Particle Size and Zeta Potential Measurement Techniques

Abstract

Silica scaling remains to be a major restriction for geothermal heat extraction and continuous operation. Numerous studies have been conducted both in the laboratory and in the field but the mechanism of growth, transport and attachment are not yet fully understood. Thermodynamic evaluation, through the calculation of silica saturation indices, could be further refined by macromolecular characterization techniques on the early polymerization phase, or the nanocolloidal silica formation. This study evaluates the capability of various particle’s size and electrokinetic potential measurement techniques to examine the possibility of silica scaling of simulated geothermal brine at fixed temperature. In addition to the standard silicomolybdate tests, the brine were subjected to evaluation by obtaining the particle’s zeta potential and hydrodynamic radius in solution thru dynamic light scattering, and apparent radius thru atomic force microscopy, scanning and transmission electron microscopy. The information gathered and correspondence could expand the understanding of silica scaling, and present opportunities for improved inhibition technologies. These techniques were extended to evaluate available chemical inhibition techniques, and the nanocolloidal silica profile comparisons could refine the application of such technologies.