Buffering apabiliti of B-chloropropionic Acid-Sodium B-chloropropionate Slstellin Acidic Geotherllal Brine

Yolanda P Brondial

Yolanda P Brondial Chemical Engineering Department, De La Salle University

Keywords: Acidic geothermal wells, B-chloropropionic acid-sodium B-chloropropionate (BCPH NaBCP) buffer, corrosives, geofluid, pH buffering

Abstract

The Philippines, being part of the Pacific "Ring of Fire," has abundant geothermal energy. Since a substantial number of drilled wells produce acidic geofluid with high enthalpy and high wellhead pressure, it becomes imperative to develop these wells for power generation. A potential pH-buffering method for commercializing high- enthalpy acidic geothermal wells was explored in this study to raise the pH of the geofluids to ~3.5, the level considered by geothermal reservoir engineers to be noncorrosive to low-carbon steel. The noncondensible gases of acidic geothermal wells are relatively high in H2S and C02 while the brine is high in sulphates. These substances, aside from being potential hazards, account ror the acidity of geofluid. Design-Expert@ 6 was used in modeling pH buffering using five design factors (pH geofluid, pH BCPH-NaBCp, volume BCPH-NaBCP, concentration BCPH-NaBCp, and temperature of solution) and one response factor (pH of resulting solution). Two experimental designs were used for the study. Experimental laboratory results showed that BCPH-NaBCP could raise the pH to >3.5 and that the initial pH of the geofluid as well as the pH, concentration, and volume of the BCPH-NaBCP solution significantly influenced the stable pH of the final solution. The best combination of factors was then used in a bench scale setup to investigate the possibility of applying pH buffering at high velocity. Results showed that BCPH-NaBCP was useful for fast buffering and could be used to commercialize acidic wells.

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