Can a pipe designed for saturated steam be modified to carry superheated steam?
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I’m facing a problem at the moment: the diameter of the saturated steam pipes is not sufficient for the expansion of the project. I have an idea: could the 12\" pipes that were originally used for 1.0Mpa saturated steam be modified to handle 1.0Mpa superheated steam instead? Could everyone help me think of some solutions? What are the things to keep in mind? This post was last edited by WSL01218 on 2009-2-6 at 15:05.]
Just in terms of the medium, since it is steam before and after the modification, there should be no problem. It is recommended that the original owner consider whether the material of the pipes is suitable for a design temperature of 1.0 Mpa superheated steam. Also, whether the insulation material needs to be made thicker appropriately.
It needs to be calculated to determine.
What was said upstairs is quite good; I’d like to add that one should pay attention to the temperature of the superheated steam. If it’s above 425 degrees, heat-resistant materials should be used, and alternatives should not be employed
The information you provided is incomplete. What is the temperature of overheating, and what is the material of the pipe? How thick should the insulation be? If judged by conventional standards, there should be no problem.
The temperature of steam at 1.0 Mpa is 180 degrees, while the temperature of superheated steam at 1.0 Mpa should be above 250 degrees; the difference is not significant, and since the pressure level is the same, it’s completely fine.
It depends on whether the temperature of your superheated steam exceeds the design temperature of the original pipeline. In principle, it is not allowed.
Let’s recalculate it; I think there should be no problems generally, but the insulation layer needs to be made thicker as well
The superheated steam temperature is around 250 degrees, the pipe material is carbon steel, and the current insulation thickness is 100 mm
Previously, the saturation temperature for 1 MPA was around 180 degrees; now it’s 250 degrees and the pipes have a DN300 diameter. It is recommended to carry out stress calculations again – this isn’t something to take lightly.
This relates to the renovation of pipelines; the original design team responsible for the pipelines should provide suggestions for the modifications. Factors such as the temperature of the superheated steam, the materials used, compensation mechanisms, and non-destructive testing must all be taken into account. The classification of the pressure pipeline also changes according to GB20801. Without recommendations from the design team, no changes can be made.
The information you provided is incomplete! Generally, changing the medium inside a pipeline requires calculations by professionals in piping engineering!
Pressure pipelines are classified as special equipment, and any modifications must be carried out by units with the appropriate design qualifications.
Thermal expansion of the pipeline should be taken into account, as well as the choice of compensation method; it is dangerous if thermal expansion cannot be absorbed in a timely manner, since expansion is related to temperature.
This really needs to be calculated before it can be done properly
With a pressure of 1 MPa and a temperature difference of 70°C, there should be no issues regarding the pressure rating. For large-diameter pipes, it is crucial to consider thermal expansion; it is necessary to determine whether the expansion compensation measures are sufficient to meet the requirements.
Be sure to note that I’ve encountered such a situation here. The operating temperature of the compensator must be determined, and the amount of compensation required for the pipeline should be limited; otherwise, it may cause damage to the compensator
The friends upstairs mentioned that the operating temperature of the pipes has increased from around 180 degrees to around 250 degrees. From the perspective of the pipe material grade, there is no problem; such a temperature change isn’t significant. However, what’s most important for steam pipelines is stress calculation. A temperature increase from 180 to 250 degrees has a significant impact on thermal stress, and it’s necessary to conduct new calculations to determine whether the existing thermal compensation is sufficient to handle these temperature changes. If not, the consequences could be severe.
For example, taking a 100-meter pipeline as the case: for saturated steam, it is 180 degrees. For a 100-meter pipeline, the thermal expansion amount is ΔL=232.2 mm for superheated steam at 250 degrees. For the same 100-meter pipeline, the thermal expansion amount is ΔL=322.5 mm. Therefore, a comprehensive consideration is necessary, especially at the expansion joints.
The medium is in a fully vaporized state; after superheating, the pressure might have been reduced too much, so the pressure remains unchanged, and it should work
The pressure resistance is no issue; the key factor is temperature. It’s necessary to determine what temperature range the pipes designed in the past could handle, and considering the higher temperature of the steam nowadays, comparing these values will resolve the problem! !