The steam pipeline is too long, resulting in a heat loss of 4 tons per day. Is this normal? I hope experts can help calculate it
Thread Content
The company has newly installed a set of external steam pipelines with a length of 500 meters and a diameter of DN150. The insulation layer is designed to be 70 mm thick, but in practice it was made 100 mm thick. These pipelines have been in use for over half a year now. A flow meter has been installed at each end of the steam pipeline. The company’s steam consumption is between 1.5 and 2 tons per hour, resulting in an average daily difference of 4 tons between the readings from the two flow meters. I would like to ask the teachers: Is this normal heat loss? Sometimes, the smaller the amount used, the greater the difference. Could it be that the pipe diameter was chosen to be too large during the initial design?
It’s normal for there to be a large difference when the amount used is small; heat is lost in that process. You can check the steam flow rate – 10–15 m/s is considered a reasonable value
The last edit to this post was made by At the foot of Hengshan Slope on 2017-4-6 at 13:31. Firstly, the type, selection, and installation of flow meters affect their accuracy and repeatability; it is likely that the measurement data from two flow meters installed in the same location will not match； Secondly, heat loss in the pipes increases the moisture content of the steam, and the condensate itself affects the measurement of the flow meter. Finally, when the flow rate is at its lowest, it may have exceeded the limits of its measurement capability, resulting in a loss of accuracy. At this point, the flow meter used for settlement usually has a fixed value set already.
Are two of them mass flow meters? Is there no branch pipe between the two flow meters?
Thank you, the flow rate should be around 15–20
Mass flow meter, without any branch pipes in between, only expansion joints and traps
I just checked the standards and posted a thread – the steam flow rate is related to the pipe diameter and the superheating condition
Then it’s easy to analyze: 1 Some of the gas is converted into condensed water, affecting the measurement. There is an error in the flow rate of 2 itself, so it’s impossible to achieve precision. 3: A smaller dosage results in more water condensation; large deviations are normal
The diameter of yours is a bit too large; a 150-diameter pipe is more than sufficient to handle 10 tons of flow. The flow rate of 10–15 mentioned earlier is too low; for steam, the normal flow rate within a plant is 25–35 M/s for saturated steam, and 35–50 M/s for superheated steam. Before designing steam pipes, we conduct calculations first to ensure that the pressure requirements are met, and then we calculate the heat loss; here, the loss refers to mass loss, not energy loss, as superheated steam can exist without any mass loss. By combining these calculations, the most suitable pipe diameter is finally selected. In short, this design is unreasonable.