Identification and treatment of corrosion as a hazard in power plants in Sudan

Abstract

In this study, problems of corrosion and environmental hazards affecting the electrical power generation plants and the surrounding areas were undertaken. In addition, gas turbines’ hot Gas Path Parts Failure due to hot corrosion was also investigated. The study extends to cover the cooling water system at Kassala Electrical Power Generation Plant and the causes of serious hazards manifested in concrete cubes tests failure in Kosti Power Station Project. The study revealed that the cause of the high level of corrosion in some parts of Garri Power Plant was due to the dissolved ammonia that contaminates water used for cooling the power Plant. In Kassala Electrical Power Generation Station the underground water pipes corrosion problem was studied. Water was sampled from 100 wells around the area and analysed for determination of water quality and records of water analysis in the area were traced for the period from April 2000 to December 2009. Results shows high metal deposits as well as microbiological fouling which directly lead to deterioration of the cooling system. The level of water hardness was found to reach 700 ppm in both cooling water system and power hole. The investigation in the causes of cube failure test at Kosti Power Plant project let to the fact that the concrete was subjected to excessive heating due the hydration heat librated during concrete setting. Remediation of the problem was suggested in terms of controlling the concrete temperature by mixing ice and using child water hence compensate for excess of heat generated during setting. The suggestion was applied and completely eradicates the problem. The study show that The level of dissolved ammonia in cooling water was as high as 1.3 ppm during summer and 1.9 ppm during winter, while the recommended standard for water to be used in such cooling systems demands that dissolved ammonia level should be zero. Furthermore, Thstudy found that the presence of high amounts of sodium and vanadium in the fuel used in the station was a major cause of corrosion. The levels of these metals far exceed the recommended level by the turbine manufacturer. Finally, the study examined Elroseris and Jebel Aulia hydro power generation plants problems. The major causes of the high iron corrosion and high deposits were due to the activities of Bacteria. Consequently remediation was suggested and applied successfully