In order to tap the deep peak shaving capacity of existing coal-fired boilers

the various headers and a large number of water wall tubes of the 660 MW supercritical boiler of unit No.7 in Huaneng Qinling power plant were respectively equivalent to pressure nodes and flow loops

and a nonlinear mathematical model based on the flow network system method was established. According to the conservation laws and heat transfer correlations

the hydrodynamic characteristics of the supercritical boiler at 660 MW(BMCR) load were directly solved by iteration

and the calculation results were compared with the actual furnace data to verify the correct reliability of the model. On the basis of actual furnace test research

the variation of water wall pressure along the flow direction

loop flow distribution

outlet steam temperature distribution

and tube wall metal temperature along the furnace height at 132 MW(20% BMCR) deep peak dry operating load were calculated. The actual furnace test and calculation results show that

the hydrodynamics of the supercritical 660 MW boiler with rifled spiral tubes have break through the limit of 30% BMCR minimum start-up load. Safe and reliable hydrodynamic operation at 20% BMCR deep peak load has been achieved

and the flow stability is good.