mechengineer
Mechanical
- Apr 19, 2001
- 256
If the design pressure minus the operating pressure (design margin) is larger than the operating static pressure, it shall consider the design pressure included the liquid static pressure. For example, a horizontal vessel, the liquid static pressure may be equal or less than 0.4 bar only, the design margin (design pressure more than operating pressure) may be 5 ~ 10 bar or more than that due to safety valve setting pressure, system maximum design pressure, liquid gas saturation pressure or whatever any reason. In this case, the operating static pressure should be considered to be included in the design pressure. No matter what is the design pressure, just add the operating static pressure to design pressure is not a good engineering design work. Secondly, using 0.1 bar, 0.2 bar ....small amount of operating static pressure plus the design pressure to check each nozzles is not an efficient engineering work. You may have a lot of comments on it, especially when the operating liquid level changed. And sometime the round off by software may not so accurate, it is unnecessary struggling with 0.1~0.4 bars of small amount of pressure in design. To settle this issue, first, a design engineer does not calculate so small amount of pressure separately to your customer. Just to consider the design pressure included in the small amount (0.5 bars) of operating static pressure except for tall column cases.
