Selecting a Tank Rating 1

[pcbaulch]

I am designing a tank and need to know how to select the rating. I am not concerned with the size at the moment. Light Algerian naphtha (SG = 66) at 12.9 Reid vapor pressure is flowing in at 9300 gpm, 100 psig and 100°F. I learned from a chart that 12.9 RVP corresponds to 13.9 psia true vapor pressure. The tank will also receive a nitrogen line that will flow at 2000 lb/hr, 10 psig, and 78°F. This tank is being designed for the purpose of mitigating pump hammering when ships are being stripped of naphtha and the ship's pumps lose flow. The tank will be placed between the ship and pumps and will provide a continuous flow of naphtha to the pumps. Thanks.

 

[MJCronin]

pc...

In establishing a design pressure and tempetature for a tank/pressure vessel, you must consider the following:

- Maximum operating pressure and temperature
- Possibility of vacuum
- Preferred materials
- Preferred flange types
- Tank/vessel head preferences
- Corrosion allowance

Based on what you have stated above I suggest that you specify a tank/vessel MAWP of 150 psig at 150F. Vacuum is another consideration

I believe that you can use ANSI Class 150 flanges (or whatever DIN equvalent)

Most carbon steel materials are specified with a 0.0625 inch corrosion allowance for this kind of service, but you may wish to increase this to 0.125 inch if the surroundings are very corrosive

Dished heads are an economic choice for this pressure, either elliptical or ASME F&D types

The design volume and diameter are up to you....

hope that this helps....

My opinion only,

-MJC