A study on variable operating characteristics of a direct air-cooling exhaust steam extraction heat supply system

Abstract

The high backpressure heating mode of direct air-cooling unit faces limitations due to the return water temperature of heat network and the coordinated heat exchanger unit control of air-cooling island. This limitation complicates the task of achieving a balance between operation economy and power generation output. To solve this inherent contradiction， Ebsilon Professional， a commercial software， is used to calculate and analyze the key parameters of the direct air-cooling exhaust steam extraction heat supply system. These parameters include the backpressure of the air-cooling island， steam turbine output and heat consumption， and suction coefficient of the injector under different loads and variable operating conditions. The calculations reveal that， during low load in winter， the optimal operating backpressure for the heat supply system falls within the range of 13~20 kPa， which allows for the gradient utilization of heating energy， ensures a balance in unit output， and meets the safety requirements for preventing freezing.

Keywords

• exhaust steam extraction heat supply
• direct air-cooling
• variable operating characteristic