Operating Experience with Fire Resistant Turbine Control Fluid at Ramin Power Plant

In the last 30 years, the phosphate ester fire resistant fluid, OMTI, has been used in the electrohydraulic control systems at Ramin power plant. Difficulties in obtaining supplies of the fluid led to efforts to extend its service life of the fluid by on-site conditioning and, eventually, to searching for a replacement. This paper surveys the operating experience obtained during the past ten years with the different forms of treatment and the replacement of OMTI by an alternative phosphate ester fluid. Different methods for conditioning of waste oil has been used from alkaline washing to ion exchange treatment. In alkaline washing process, an aqueous potassium hydroxide (KOH) solution was used to neutralise the acidity of the fluid. Any potassium soaps that are formed partition into the aqueous phase and can then be moved. Since it was done on a small-scale batch process, a static separation process was used. But in ion exchange treatment adsorption of acidic material of waste oil on ion exchange resins was used for reclamation of the oil. In view of concerns expressed over the conditioning of the used fluid and trade restrictions on purchasing the new fluid, the availability of a phosphate ester fire–resistant fluid from other sources was investigated and a different fluid, Turbex F46, was identified as potentially suitable.