| Title | Modification of Condenser Nozzle and Cooling Tower Exit Screen to Increase Condenser Performance |
|---|---|
| Authors | Amri Zein, Paul A. Taylor, Heribertus Dwiyudha |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | Wayang Windu, condenser pressure, nozzle, gas cooling zone, performance, cooling tower |
| Abstract | The cooling water (CW) design flow to the condenser of Unit 1, 110MWe Wayang Windu Geothermal Power Plant, West Java, as per heat balance is 4639 kg/s. Although this flow was achieved during first commissioning, it reduced quickly in normal operation which caused the condenser pressure to increase above the design pressure of 0.12 bara and resulted in a loss of generation. After investigating the condenser during a major maintenance shutdown in 2003, it was determined that reduction in water flow was caused by fouling of nozzles, particularly those installed in the gas cooling zone. There are two types of gas cooling zone (GCZ) spray nozzle which are full cone nozzle (with upstream bore diameter and down stream bore diameter is 5 mm and 7.5 mm respectively) and flat type nozzle which has progressive opening width from 5 to 8 mm and length 11 mm respectively. Fouling at GCZ nozzles is caused by bugs (or beetles) which pass through the Cooling Tower (CT) exit screens. However, no significant fouling of the main condensing zone (MCZ) spray nozzles was observed which indicated that bugs will not cause fouling in 20 mm diameter nozzles. Over the next 2 years, Star Energy Geothermal (WW) Ltd (SEGWWL) attempted to significantly improve the management of cooling tower screen design and cleaning, but cooling water flow reduction continued to occur albeit at a reduced rate. SEGWWL conducted an engineering study and recommended that condenser performance can be significantly improved by enlarging the diameter of full cone type GCZ nozzles and installing fine wire mesh at the Cooling Tower (CT) exit screen which will act as a filter of bugs or other debris before flowing to condenser. The modification of full cone type GCZ nozzle’s diameter and fine wire mesh installation which was completed in 2005 improved the condenser performance and stopped the reduction of CW flow caused by fouling. The annual average condenser pressure reduced from 0.13 Bara to 0.11 bara. The average cooling water flow is increased by approximately 3.5%. Furthermore, the improvement in condenser performance increased the average power generation by approximately 1 to 2 MW. |