News

MSc defence by Daniel Wanga Odongo

15 May 2024

Daniel Wanga Odongo from Kenya, MSc Fellow in Sustainable Energy Engineering at Reykjavík University will present his MSc project on Thursday 6th of June at 13:00 at Reykjavík University (location to be announced).  

The title of the project is:
Application of supersonic ejector principle to enhance flow in low-pressure geothermal production wells

Daniel's supervisors are:
María S. Gudjónsdóttir, Associate Professor, Reykjavík University, Iceland

Abstrac
Geothermal wells are one of the key components and most capital-intensive parts of any geothermal power generation facility. However, they often experience pressure decline over their lifetime, leading in some cases to the well pressure falling below the power plant operating conditions, which make wells unsuitable for power generation. This can make the overall project more costly since additional wells must be drilled to compensate for the unavailable wells to maintain the desired power plant output. This study explores the possibility of using ejectors to solve that problem. Ejectors have been used in various applications in oil and gas and refrigeration. In geothermal power generation, ejectors are widely used to extract non-condensable gases from the condenser. Supersonic ejectors are devices that use kinetic energy from a high-pressure stream to induce flow from a lower-pressure stream. They work by using a convergent-divergent nozzle to accelerate a primary fluid to supersonic conditions. This create an under-pressure that allows a secondary flow to entrain, and the mixture exits at an intermediate pressure. The experiments described in this work were carried out to test a supersonic ejector on a laboratory-scale setup to connect two streams of saturated steam at different pressures and validate the analytical model developed in earlier studies. The experiment was focused on the effect of ejector dimensions on performance, especially the constant area mixing section (CAMS). From the experiment, the 5 mm CAMS provided the best results. The results were then used to validate and update the analytical mode and also design a suitable supersonic ejector for two production wells in the Olkaria geothermal field in Kenya.