Pressure rise rate, or temperature increase rate, of the SS\ HS heating pipes in the ethylene plant
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What is the pressure increase rate, or temperature rise rate, for warming the pipes using superhigh-pressure steam at 11.6 MPAG and high-pressure steam at 4.2 MPAG in an ethylene plant? Are there specified values in the national standards?
1. First, let me correct this: steam with a pressure of 11.6 MPa(g) is classified as high-pressure steam, while that with 4.2 MPa(g) is considered medium-pressure steam. It’s not appropriate to label everything as ultra-high-pressure just because it involves ultra-high-pressure polyethylene. I shouldn’t be so pedantic; after all, I’m just a planner. Sorry about that :) 2. No matter what type of device it is, steam pipes are thermal pipelines, and they have their own specific characteristics. 3. During the pipe warming process, there is no rate of pressure increase; throughout this initial phase, the pressure will not exceed 3 kgf/cm2 (until steam starts to flow in the drain lines). The temperature rise rate during this entire process must not exceed 30–50 degrees per hour. 4. Most importantly, it is necessary to ensure that the expansion of the piping system is normal, and that water continues to be discharged from the drain lines. 5. If everything checks out, what is the steam temperature at the user side? Once it reaches 30-50 degrees above the superheating threshold, the steam can be introduced; otherwise, regardless of the amount of steam, it must be vented! 6. To warm the pipes more quickly, it’s not about closing the valves to build up pressure, but rather increasing the venting. If there is no flow, then how can heat be transferred! :Lol, if there’s anything wrong, please point it out. Wish you success in your work!
It’s probably because different companies have different regulations. At Jilin Petrochemical, 11.6 MPAG is referred to as HP, while 4.2 MPAG is called MP. In the technical specifications for our new installation, provided by the foreign supplier, 11.6 MPAG steam is designated as SUPER HIGH PRESSURE STEAM, and 4.2 MPAG steam as HIGH PRESSURE STEAM. You’re absolutely correct regarding the term used for steam; I’m just wondering if there are any specific standards set by national regulations. Anyway, thank you very much.