NGAWHA OEC4 GEOTHERMAL FLUID SEPARATION – HORIZONTAL SEPARATOR SELECTION AND PERFORMANCE

Abstract

New Zealand has a long history of developing higher enthalpy geothermal fields. This has meant that the cyclone type separator design has been preferred. The Ngawha geothermal field has a low enthalpy when compared to all New Zealand’s other developed fields. A horizontal separator was selected for Ngawha OEC4, primarily because of low pressure loss when compared with the cyclone type. The separator was easy to commission. The separator performance was tested using sodium as a tracer. Separation efficiency is like what is expected for a cyclone separator. The performance of condensate drop-pots designed for steam scrubbing was also compared to condensate drop-pots intended to capture excess condensate only. The results show that the first condensate drop pot
makes a significant difference to the steam purity, but the downstream condensate pots do not irrespective of the steam velocity.