7 replies to this topic

[Sherif Morsi]

Hi,

 

This is more of a mechanical question, any reference/guideline for the estimation of the weight of pressure vessels? Given that I know the material of construction, thickness, the dimensions.

 

Thanks,

Sherif

[Bobby Strain]

You can use carbon steel weight of 490 lb/ft³.  Then the rest is arithmetic.

 

Bobby

[Sherif Morsi]

Hey Bobby,

 

Thanks for the reply. 

 

I am using the equation Pi/4 D^2 x L to get the volume. My question here would be how to account for the thickness in the "D" factor?

[Bobby Strain]

Well, you have it all wrong. You need to get the volume of the metal, not the volume of the vessel. If you go to my website (Google my name) you will find a calculator that gives you the surface area of the vesssel. From this you can calculate the volume of metal, and hence its weight.

 

Bobby

[latexman]

If volume is calculated using the outside diameter, then subtract the volume calculated using the inside diameter, what is the remaining volume of?

 

Pi/4 D_o^2 x L - Pi/4 D_i^2 x L = ?

 

A similar method can be used using the volume equation of a head.

[curious_cat]

Pi * D * L * thk * density 

 

will also give you a reasonably close value. 

[Bobby Strain]

So, nobody want to bother with the weight of the two heads? Sherif, maybe you can start with the simple approach. But omitting the heads is just being lazy. If you take the approach of calculating the difference in volumes as suggested, the numbers must be calculated to a number of significant figures. For example, a 13 ft diameter vessel with a 1 inch wall thickness. On the other hand, calculating the weight as suggested by the Cat, one is not trying to resolve the difference between two large values. Try it and see. If you apply your knowledge of geometry, and the fundamentals of math expressions, you will reasonably conclude that the direct calculation has less likelehood for error. So, you should now have enough information to complete your exercise.

 

Bobby

Edited by Bobby Strain, 06 October 2015 - 10:56 PM.

[Napo]

Sherif Morsi,

 

You can review "Simple weight calculations for steel towers and vessels", by A. Jordans, Hydrocarbon Processing, August 1981, p. 146.

 

Napo.