Increased Generation Performances by Using Sulfur Dispersant in the Cooling Tower at the Wayang Windu Geothermal Power Plant (A Lesson Learned from Wayang Windu Geothermal Power Plant Operation)

摘要

Cooling tower performance is the essential instrument to maintain an efficient geothermal Power operation. The historical data from the Wayang Windu Geothermal Power Plant shows that all microbiological cooling water parameters are much lower than the allowable limit; however, it shows that the cooling tower temperature increases about 0.3 °C that equals with 0.3 MWe decrease of the electricity production per year. In the geothermal operation, sulfur sediments is found around water distribution, nozzle and fills etc from the non-condensable H_2S gas that can potentially decrease the cooling water performances. The plant performs mechanical cleaning at least on yearly regular basis that needs at least 1 week shutdown of each single cell of cooling tower (8 cell total for each unit). The field operation team initiated literature study and developed the prototype scale by installing the bio box. The inside bio box put CT small CT fill, than flowing by condensate injected with some chemicals to make sure the potential control of the sulfur sediment during filling inside the boxes. The sulfur deposit on the box injected with some chemicals had the smaller particulate and was easier to wash off. The trial was continued with actual injection to cool down the system with several dosages of chemicals in 6 months period, and the result showed significant improvement of main cooling water temperature. In 2013 WW operation decided to perform injection control of sulfur treatment in the cooling water system. The following year we found that we need not to clean sulfur sediment in pipeline mechanically anymore, and the approach temperature decreased about 0.23 °C (better performance than the previous condition). Although it was successfully implemented in WW Geothermal, the treatment could not be implemented directly in other power plants due to the differences of site-specific characteristic of cooling water content. The beginning the process approach by literature study, used the mini scale box than continued by full scale of cooling system. The same process approach potentially conducted in other geothermal plant to minimize the potential risk to the running Plant when applying optimum chemical dosage. In overall the trial is success in controlling sulfur deposit at the main cooling system, at the time operation conducted continuous using sulfur dispersant in the main cooling water system operation.