Improved Energy Harvest Potential from Highly Corrosive Geothermal Fields: Laboratory Formulation Developments

Abstract

To meet the urgent demands of Taiwan’s energy diversified governmental policy by 2025, we take on the endeavor of expanding the exploitation operations focusing on screening potential geothermal resources across whole region. Numerous examples of the acidic conditions of geothermal fluid observed exhibit presence of extremely corrosive fluids (pH < 2) at the sites investigated; thus, any attempt of building
full-scale power plant and whole project would be cost prohibited under such harsh conditions. To alleviate some of these unique challenges, we explored the potential of developing injective amendments and formulations targeting for the production wells, aiming to effectively neutralize extreme acidity of geothermal fluids in-situ to allow better transport of hot fluid while provide reliable power generation
and safe plant operations.
We have successfully developed several potential formulations indicating some unique characteristics as, 1.
reasonable chemical dosage (0.5 to 2.3 wt%), 2. rapid reaction rate (between minutes to few hours), 3. elevated temperature activated (reactions occurred only after reach the threshold level), 4. safe chemicals and low cost, 5. minimum or no scaling formation or line plugging concern (unlike simple alkaline case).
Results of this study reveal the newly developed formulations can be easily adapted to a variety of fields inherited with strong to extreme acidic geothermal fluid conditions. And they demonstrated superior performance in modifying acidic geothermal water to weak acid or neutral, and the post treated samples showed no sign of scaling after few weeks or extended period. We anticipated the improved chemicals
offer great potential to mitigate the excessive damages caused by acid erosion of the pipelines and generators, while reduce the maintenance costs of pipes and machinery. Further investigations are underway to verify the effectiveness of these formulations for a variety of geothermal fluids retrieved
from sites under different site-specific conditions to collect additional engineering data for the planned field pilot test.