Assessment of Solid Deposition in Geothermal Power Plants Based on Thermodynamic Precipitation Modeling an‎d Process Simulation

10/22/2026 12:00:00 AM

Given the detrimental impacts of mineral scaling on the efficiency an‎d economic performance of geothermal power plants, precise modeling of this phenomenon has become an undeniable necessity. Deposits such as calcite, carbonates, silicates, an‎d metal sulfides are commonly encountered in different sections of geothermal systems. This issue is particularly critical in multi-stage power plants (flash an‎d binary), where steam separation processes are more complex. This research aims to quantitatively predict the rate of salt deposition in several representative geothermal power plants. Accordingly, a thermodynamic simulation of the plant cycle was performed using Aspen HYSYS, applying the NRTL model for the liquid phase an‎d the SRK model for the gaseous phase. To simulate the kinetic formation of key minerals, including calcite (CaCO₃), amorphous silica (SiO₂), an‎d barite (BaSO₄), output data from the thermodynamic model—such as temperature, pressure, an‎d key flow rates—were transferred into the specialized geochemical software PHREEQC.The developed integrated model revealed distinct scaling patterns an‎d identified the critical equipment in each geothermal power plant over a five-year prediction period. In the single-flash plant, the separator was found to be the most critical component, accumulating 5.46 kg of scale, predominantly composed of calcite. In the double-flash plant, the high-pressure separator exhibited an accumulation of 2.96 kg of dolomite, with the simultaneous presence of barite (saturation index SI ≈ 3.96). Conversely, in the binary plant, although the working fluid circuit remained entirely free of scale, the TEE-100 connection, with 1.086 kg of dolomite deposition, was identified as the most critical point for analysis. This integrated thermodynamic–kinetic modeling framework provides a powerful tool for predicting scaling behavior an‎d developing optimized, plant-specific control an‎d mitigation strategies.

انرژي زمين گرمايي , رسوب‌گذاري معدني , نرخ تجمع رسوبات , شاخص اشباع (SI)

Geothermal energy , mineral scaling , scale deposition rate , saturation index (SI)

Narges Shamoradi samani

Mehdi Asareh