Experience in Application of Fire-Resistant Liquids in Automatic Control Systems of Steam Turbines at TPPs

Currently, in order to ensure fire safety, fire-resistant fluids are used in the electro-hydraulic control systems of high-capacity steam turbines in thermal power plants. In the Soviet Union and some other countries, fire-resistant OMTI oil, which consists of a mixture of trixylenyl phosphates, was used and similar oils have been used since the beginning of the 1990s. The accumulated experience in the use of fire-resistant liquids allows us to conclude that their quality has a significant impact on the reliability of turbine units. Improving the reliability of the oil systems of steam turbines and other thermal mechanical equipment, as well as increasing the service life of turbine oils, is of wide scientific and industrial interest. The results of long-term studies into the quality of fire-resistant liquids during their operation in automatic control systems of steam turbines of power units of combined-cycle plants located in the central and southern parts of Russia are presented. The objectives of this study were to determine the reasons for the decrease in the resource of fire-resistant liquids and the formation of proposals for updating regulatory documents for their use and quality control. The issues of ensuring the regulatory requirements for fire-resistant liquids are considered, the volumes and methods of conducting chemical analyzes of their quality are analyzed, proposals are made to adjust the instructions for operating equipment and the scope of tests, the causes of aging of fire-resistant liquids are determined, and ways to extend their service life are proposed. Based on the production experience of using imported and domestic fire-resistant liquids, conclusions were drawn about the impact of the quality of the original product and the operating mode on the quality of the oil during its operation as well as the importance of informing the responsible services of the operating organization about the compliance of the production process with the requirements of current regulatory documents.