Hydraulic Power Recovery Turbine Operational Failure and Design Enhancement

Abstract

Case Study 23: PTT operate a number of hydraulic power recovery turbines (HPRT) in their gas processing plants in Rayong Thailand. One of the newest plants incorporates some of the largest such turbines ever produced. The HPRT design under discussion includes an inlet guide vane assembly and a double flow runner required to meet system NPSHa (evolution of dissolved gases) and for axial thrust balance. Within this class of equipment, special consideration must be given to metallurgical selections, robust bearings, as well as seal designs owing to the mixed phase discharge conditions. Within the first year of operation, several turbine issues were observed. This case study seeks to describe the nature of the issues, as well as the resulting evaluation and root cause analysis. Further the case study will describe the design improvements being implemented.