I would like to ask the experts: When one of our steam pipelines was put into operation, during the warming-up process, the temperature kept rising first and then falling, and the reason for this is unknown
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A steam pipeline has been put into use in the company; it is quite long, about 2 kilometers in length. Before heating the pipeline, steam at a pressure of 1.0 MPa and a temperature of around 300°C is used, at a flow rate of 15 T/H. After that, steam at a pressure of 1.6 MPa and a temperature of 375°C is used for heating, at a flow rate of 110 T/H. The temperature readings show that the temperature first rises to 230°C, then drops to 180°C, before gradually rising to 280°C, at which point the pipeline is ready for operation. This process takes approximately 2–3 hours. I would like to ask the experts: what could be the reason for this behavior?
Is there air in the pipeline? Looking at the relationship between pressure and temperature, superheated steam is used for warming the pipes. Superheated steam has a slow heat exchange rate; initially, it might be superheated steam that is detected. As the warming process continues, the superheated steam turns into saturated steam, which could result in a decrease in temperature. After further warming, the saturated steam turns back into superheated steam, and then things stabilize. This is just my personal opinion