双抽供汽机组供汽流程优化与能耗特性研究

Supplying multi-parameter industrial heat loads is an effective method for coal-fired units to improve energy efficiency. The optimization of the steam supply process and energy consumption characteristics under off-design conditions are of great significance for energy-saving renovation and operation optimization. In this paper, with a 1000 MW unit as an example, optimization on the double-parameter industrial extraction steam supply system is carried out, and the energy consumption characteristics of four steam supply methods under typical operating conditions are compared. It is found that the energy efficiency of the heat mode with cold reheat steam for intermediate pressure steam (IPS) and intermediate pressure turbine (IPT) exhaust steam for low pressure steam (LPS) is the highest considering different operating conditions. Furthermore, the energy consumption characteristics in the operation domain under all operating conditions is studied under three modes, i.e., the mode with cold reheat steam for IPS, the mode with IPT exhaust steam for LPS, and the mode with cold reheat steam for IPS and IPT exhaust steam for LPS. The energy efficiency of the unit varies greatly along with operation conditions in the operation domain. When the IPS mass flow under the double extraction steam supply mode is 223 t·h⁻¹, the maximum and minimum energy efficiency in the operation domain are 67.90% and 50.45%, respectively.