Shell thickness for an Indirect Heater
Goodmorning,
i have to design an indirect fired heater to heat a stream of crude oil.
I have sized all the process, what remains is to calculate the [B]thickness of the shell[/B]. The API 12K only tell me that i have to design the shell based on Asme VIII div. 1, but it gives me no other inputs.
The shell has these dimensions:
-lenght: 15000 mm
-diameter: 3600 mm
-full of liquid (water/glycol)
-design pressure: atmospheric
-material: carbon steel
How can i calculate the vessel thickness in order to be sure that the vessel will resist to the weight of the water? Is there any formula?
I've tried to use the formula given by ASME regarding pressure vessels, but it gives me a ridocolous thickness (1mm). I think i cannot use this formula to calculate the thickness of an atmospheric thanks
p.s. My boss suggested me to consider a thickness of 12 mm, but i would like to understant WHY he gave me that number...
Thank you
Matteo
Re: Shell thickness for an Indirect Heater
Dear Sir
It would be greatfull if you could share this manual for us. I need it ergently for my work. In fact I dont khow how I shold size fire tube to sure the required heat released to heating medium is sufficent.
Best regard
Re: Shell thickness for an Indirect Heater
API 12K latest addition will give guidelines to determine the diameter of the firetube. The length has to do with the flame length as you want to have several feet past this distance at high fire. This distance determines the main leg of the firetube and if it is a return type then two times that distance will give you the total length for surface. You may need more surface for forced draft burners that can fire into smaller diameter firetubes than what is used for natural draft. The length of the first leg will also determine the overall length of the water bath shell. Since the shell is open to atmosphere then the only pressure you have is the height of the liquid. The main concern there is not so much the shell itself but the end plates. The thickness of them is more guided by the height of the liquid and the fact you have force on a flat plate. A good book to have is the 'formulas for stress and strain' by Roark & Young.
I hope this helps.
Re: Shell thickness for an Indirect Heater
hi, can you send API 12k code in pdf format