| Title | Laboratory Evaluation of Chemical Dissolution on Complex Geothermal Binary Plant Scales |
|---|---|
| Authors | Gabriel Mendoza |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | binary, scaling, dissolution |
| Abstract | The Palayan Bayan Binary Power Plant (PBBPP), commissioned in 2024, contributes 29 MW to Energy Development Corporation’s renewable energy portfolio of over 1,400 MW. To mitigate silica scaling during brine cooling (170oC to 80oC), PBBPP employs a sulfuric acid-based pH-modification system. However, operational data indicated a decline in power output due to reduced heat exchanger efficiency from scaling within the heat exchangers. Additionally, the complex scale deposits proved difficult to remove mechanically during preventive maintenance. Petrological analysis of scale samples revealed composition ranging from 25-90% silica,10-60% metal-bearing compounds (e.g. Fe-oxides, Fe-sulfides, stibnite, orpiment), and minor amounts of transported reservoir formation materials, with variability across heat exchanger locations. Laboratory dissolution tests were conducted to evaluate chemical cleaning viability. Dissolution performance varied, ranging from 10% to 65%, with one formulation demonstrating the highest efficacy on samples rich in corrosion products. These findings suggest that chemical cleaning may offer a viable alternative or complement to mechanical scale removal in geothermal binary systems. |