| Abstract |
Ohaaki Power Station is under construction on Broadlands Geothermal Field,20kmnorth of Wairakei. Limited water rights for the discharge of geothermal waters into surface waters, namely the Waikato River, were sought and granted. These have necessitated the design of reinjection systems for separated water and condensate which are the major quantities of geothermal fluid requiring disposal. The separated water reinjection system is the larger of the two systems and will be required to dispose 1500- 1700 tonnes per hour of silica saturated water which has been separated from the production steam. The system consists of five similar pumping stations, each associated with a separation plant, seven reinjection wells and aninterconnecting network of pipelines. In the paper, the design decisions taken in determining t!ie required pumping station equipment based 0;) problems associated with pumping silica saturated water, H,S pollution of the environment and uncertainties in the fluid quantities and reinjection pressure are discussed. In addition, the proposed control of the reinjection system using electronic variable speed driven pumps is outlined. |