Bacman Geothermal Production Field Experiences in Silica Deposition and Control Using Chemical Inhibitors

Abstract

The Botong Sector of Bacon-Manito Geothermal Production Field is an excellent laboratory for the study of silica scaling for its high silica content and pioneering works on use of antiscalant polymer for the prevention of silica scaling in geothermal system. The field process set-up has a second flash system that further increased the super saturation of silica to a concentration of 1000-1300 ppm in brine. The brine chemistry was well studied and different approaches to prevent silica scaling were tested including; a) silica slurry injection, b) cold injection scheme with brine treatment using antiscalant, c) hot injection experiments with antiscalant and d) tests with new inhibitor. The different strategies resulted to successes and failures, difficulties in operation, costs, and largely understanding of silica chemistry and disposal at Botong condition. Pilot studies on the use of polymers at various conditions showed better success and relatively more efficient system that resulted to a successful 10-year operation of Botong Power Plant.