Against the dynamic operation characteristics of three-pressure reheat waste heat recovery steam generator(HRSG) of gas turbine combined cycle(GTCC) unit

the Modelica open-source programming language is used to build the simulation model for the HRSG

and the simulation results are compared with the actual operation data during peak load regulation process of the power plant. Under actual operating conditions

the established model can accurately predict the dynamic response laws of main parameters of the HRSG in the dynamic process of steady-state operation after the load drops from full load to low load

then increases from low load to full load

as well as unit shutdown and boundary parameter disturbance. When the unit load decreases from 320 MW to 280 MW

the power of the steam turbine decreases from 124.0 MW to 111.5 MW. The high pressure main steam flow rate decreases from 70.12 kg/s to 63.62 kg/s

and the high pressure main steam pressure decreases from 8 250 kPa to 7 612 kPa. The flue gas parameters at inlet of the HRSG change in about 300 s with the decrease of the unit load

while the steam parameters of the HRSG need about 600 s to complete dynamic response and reach steady state at low load

indicating there is a certain lag in steam parameters of the HRSG compared to the change of gas turbine exhaust gas parameters over time. In the dynamic process the unit shut down

the power of the steam turbine decreases from 130.4 MW to 5.4 MW

the high pressure main steam temperature of the HRSG decreases from 600.1 ℃ to 224.5 ℃

and the high pressure main steam flow rate reduces from 76.1 kg/s to 15.3 kg/s.