| Abstract |
The Sabalan geothermal field is a high-temperature area under development. Geothermal exploration was started in 1975 by the Ministry of Energy of Iran. After revolution in 1979 in Iran, it was stopped, and it was started again in 1998 by SUNA – the Renewable Energy Organization of Iran. Three deep exploration wells and two shallow reinjection wells were drilled in 2002-2004 in three sites A, B and C, by SUNA beside the preparation of two sites D and E for new drilling. This area is about 16 km southeast of the town of Meshkinshahr. There is an overall potential for the generation of about 200 MWe over the greater prospect area. SKM (main consultants 1998-2006) assesses that commercial geothermal power generation can be achieved at Sabalan at a levelised cost of electricity of less than 5 USc/kWh. SUNA is planning to drill thirteen new wells, and build a 50 MWe power plant, when these wells will be drilled. As the first part of project, SUNA will build a pilot power plant in order to confirm, that a geothermal power plant can be operated in Iran. Moshanir was the consultant for civil work 1998-2006 and since 2006 the consortium of Moshanir, EDC and Lahmeyer was selected as main consultant for geothermal field that the new drilling was started since of 2008 till 2011. In this stage 5 deep wells were drilled and one of the privous well was be deeper. Well NWS-6D is the sixth drilled well in the second stage of exploration and third to be discharged. This well was flow tested in the time period of 7th September to 31th may in 2011. Test apparatus included a full flow atmospheric silencer associated with required piping, valves & fittings and instruments. A weir provided in the bottom of silencer is used for measuring of separated brine water flow. According to test results at six steps corresponding to six throttle valve (installed in well outlet) positions well head pressure (WHP), pH and chloride content of brine water remained constant to record water flow and lip pressure (pressure of entering fluid to the silencer) to be applied for calculation of total mass flow (TMF) and Enthalpy of outlet fluid from the well. Design of separator for separation & providing feed steam of condensing turbine of power plant is the object of present paper. Corresponding to each position of throttle valve calculation was carried out to determine optimum separator working pressure to obtain maximum output power from the generator. Calculations show optimum working pressure for selection of separator is around 5.0 barg which is about 10 barg of WHP. Also the results indicate operation of the well at high pressures cause to decrease output power of the plant below 5MW. |