Simulation of the Troitsk District Power Plant 660-MW Power Unit Boiler Startup Modes without Using the Startup Circulation Pump or Estimation of the Boiler Lower and Upper Radiant Parts’ Temperature Operating Conditions

— The HG-2100/25.4-YM16 boiler, manufactured by Harbin Boiler Co., operates as part of the 660‑MW power unit at the Troitsk district power plant (DPP). An analysis of the boiler design showed that many technical solutions adopted in the boiler differed from those commonly used by Russian manufactures. The aim of the study is to simulate and optimize the boiler startup technology without using the circulation pump (CP) but with ensuring reliable operation of the boiler components. For achieving this aim, the following main tasks must be solved: to substantiate reliable operation criteria of boiler components during the startup, to develop adapted static and adapted dynamic boiler analysis models (SM and DM, respectively), and to study the possibility of boiler starting without using the CP. The main criteria for reliable operation of the boiler’s lower and upper radiant parts (LRP and URP, respectively) are the absence of a scale formation process (the design temperature of the metal outer surface must be below its permissible value) and stable motion of medium. However, the results of predicting the steam superheating surface metal temperature in a dynamic mode are not sufficiently accurate. Therefore, the reliability criterion adopted for these surfaces was the steam flowrate downstream of the separator, the values of which in the boiler starting modes with and without the pump should be close to each other. The reliable operation criterion of the low-pressure steam superheater outlet stage (LPSS2) is the gas temperature at the furnace outlet, which shall not be higher in starting without the CP. The numerical analyses were carried out using the Boiler Designer software package. The boiler adapted static model was developed taking into account the authors' previous works and with comparing them with the results of manufacturer’s calculations. After that, the boiler adapted dynamic model was developed on the basis of its static model. To this end, the trends of real startup modes with participation of the circulation pump provided by Troitsk DPP specialists were used. Based on these data, taken together with the experience gained from the authors' previous numerical analyses and expert estimates, the dynamic model tuning was performed. Three boiler starting modes from its cold state were studied in detail: one with the pump (at the feed water temperature t f.w = 104°С) and two modes without the pump (at t f.w = 104 and 150°С). In all cases, the following s