Design Pressure And Temperature For Column

Dear all,

While designing pressure vessels like reactors, storage vessel etc there is only design pressure and temperature on datasheet. Now I am having column to design and in its datasheet there are two values one for TOP and one for BOTTOM.

Can anyone tell me, upto what height TOP design pressure & temperature shall be considered, and upto what height BOTTOM design pressure & temperature shall be considered.

what is the purpose of providing TOP and BOTTOM design pressure?

thanks

Anil,

Generaly in columns there are either trays or packing and it is obvious to have pressure drop across these elements,

so, calculate the pressure drop for each tray/packing and go on adding these pressure drop for each tray or packing for each shell barrel the pressure you get is the design pressure of that shell barrrel if you go on doing this till the end you will find the bottom pressure you got is equal to the pressure provided in the datasheet at the bottom.

hope you got my point,

Regards,
Hitesh Pawar