The behavior of silica in geothermal brine from Dieng geothermal power plant, Indonesia

Abstract

Silica scaling in the Dieng geothermal power plant was investigated experimentally. We conducted two kinds of polymerization experiments to examine the behavior of silica in brine along the canals at production wellpads. Acid-treated and untreated brines were sampled along the canal to understand the effects of acidification on silica polymerization and deposition. Chemical analysis of the Dieng brine indicated high silica and salt concentrations. Silica concentrations of acid-treated brine showed that acidification successfully suppresses the deposition of silica along the canal, preventing it from fulfilling its purpose of depositing as much silica as possible. In contrast, significant silica polymerization occurred along the canal when the brine was not acidified. Batch experiments for silica polymerization at constant temperature indicated that both concentrations of total and monomeric silica decrease quickly in early times followed by gradual decrease with time.