Geothermal Steam Turbine Deposition Fundamentals and Proposed Iapws Geothermal Steam Purity Limits

Abstract

Geothermal steam turbines are prone to forming significant turbine mineral deposits under suboptimal steam purity and quality conditions. These deposits can then lead to operational and maintenance issues that are detrimental to turbine performance, reliability and availability
The mechanisms related to how deposits form within geothermal steam turbines are discussed in relation to both vaporous and mechanical transport of impurities in steam. Saturated and Superheated steam conditions and their impact on deposition within a geothermal turbine are reviewed. The formation and behavior of the liquid films that form within geothermal steam turbines are outlined and the impact on these liquid films by reheating due to heat transfer across a turbine disk or shaft is discussed.