Application Research Of Steam Circulating Water Pump In Thermal Power Unit

The energy-saving optimization of the cold-end system plays an important role in achieving energy-saving and emission reduction,increasing the revenue of the unit and improving the competitiveness of the on-grid price.This dissertation is based on the optimization of the cold end system of a 330MW coal-fired unit.It is proposed to use a small steam turbine driven circulating water pump instead of the motor-driven circulating water pump,and carry out thermal economic simulation analysis of the two driving modes.The main results and innovations are as follows:(1)Based on the operating principle of the cold-end system,the mathematical model of each equipment of the cold-end system,including the condenser and the circulating water system,is established,and the operating characteristics of the condenser and the cold-end system are studied to obtain the coupling function between the condenser pressure and circulating water.And it lays the foundation for the subsequent construction of each equipment in the simulation support platform and the operation adjustment of the unit under the two circulating water pump drive modes.(2)A brief introduction to the simulation support platform STAR90 was carried out,and a small steam turbine driven circulating water pump unit system model was built on the simulation platform.Determine the steam turbine steam source and the steam circulating water system integration scheme.Based on the optimal vacuum of the unit condenser,the PI feedback adjustment is used to adjust the system to ensure that the steam turbine extraction parameters,circulating water system parameters and condenser vacuum are optimally matched during the variable load operation of the unit.(3)According to the system built in the simulation system,the 330MW coal-fired unit was simulated under different working conditions,the operating parameters were obtained,and the experimental data were summarized and analyzed.The plant power consumption rate,drive synthesis and output net power under the two driving modes were compared,which were referenced for subsequent practical projects.