MSc defence by Andi Joko Nugroho

5 May 2011

UNU-GTP MSc Fellows graduating in 2011. From left: Andi Joko Nugroho (Indonesia), Andemariam Teklesenbet (Eritrea), Endy Kevin Padilla Rivas (El Salvador), Alejandro Rodríguez Badilla (Costa Rica)

On Thurdsay 12th May, Andi Joko Nugroho will defend his work for the degree of Master of Science. The thesis is entitled: „Optimization of Electrical Power Production from High Temperature Geothermal Fields with respect to Silica Scaling Problems“. The defence will take place in room 158 in VRII and starts at 14.00. The Supervisors on the project are Halldór Pálsson & Magnus Thor from the University of Iceland and the external examiner is Páll Valdimarsson from the University of Iceland. Abstract

Silica scaling problem is an obstacle to the use of geothermal fluid fromhigh temperature fields. The potential issue of silica deposition riseswith increasing resource temperature. A single flash condensing system isthe most common energy conversion system for utilizing geothermal fluidfrom high temperature fields, mainly due to its smallest possibility ofsilica precipitation. This thesis investigates the possibility ofoptimizing the employment of geothermal fluid from high temperature fieldsby using an alternative energy conversion system in place of aconventional single flash cycle with a condensing turbine.

Thermodynamic and silica scaling calculation were modelled and simulatedin Matlab for five different energy conversion systems in order to getoptimum specific power output from each power conversion system. The modelincludes: a single flash and a double flash condensing system, combinationof a single flash condensing cycle and a binary cycle utilizing separatedbrine, combination of a single flash back pressure cycle and a binarycycle utilizing the turbine exhaust steam, and combination of a singleflash back pressure cycle and a binary cycle utilizing both separatedbrine and exhaust steam. An economical analysis was also performed to getthe total capital investment for different energy conversion systems attheir optimum power output production. The specific power output and totalcapital investments from different power conversion systems were finallycompared.

Results from the study show that the employment of geothermal fluid fromhigh temperature field at certain range of fluid enthalpy and resourcetemperature could be optimized by using the double flash system, thecombination of a single flash condensing cycle and binary cycle, and thecombination of a single flash back pressure cycle and a binary cycle. Thiscan be used by a decision maker to identify the most appropriate energyconversion system for making use of geothermal fluid from high temperaturefields where the silica scaling becomes a hindrance based on a givengeothermal fluid enthalpy and resource temperature.

Back