New technologies of chemical management in higashi-niigata thermal power station

摘要

This report presents the new technologies of chemical management in Higashi-Niigata Thermal Power Station.1.Development of New Turbine Oil with Improved Oxidation StabilityWe examined the effect of the dosage of DBEP as an oxidation inhibitor on oxidation stability. As a result, the newly developed turbine oil has about 30 higher oxidation stability than the conventional turbine oil.2.Extended Interval of Chemical Cleaning for Circulation BoilerWe carried out an actual plant test using the JIS guaranteed reagent (sodium phosphate) instead of the conventional chemical. As the JIS guaranteed reagent has few corrosive compounds, the corrosive rate of water-wall tubes was decreased and therefore,the interval of chemical cleaning for the circulation boiler was extended.3.Automatic Injection Method of Sodium Phosphate for Heat Recovery Steam Generator (HRSG) of Combined Cycle Power PlantWe changed the injection method of sodium phosphate from the semi automatic to automatic injection method which was controlled with the conductivity of the boiler water. In six HRSG of the combined cycle power plant, we automatically controlled phosphoric acid concentration to within the target value.