Read about START-PROF pipe stress analysis software
The pipe is not welded to heater shell like in ordinary equipment. Heater have a hole, the pipe runs through that hole inside the heater body. Analysis results can be found in Loads on Nozzles and Equipment Table. See also "How to Reduce the Nozzle Loads in START-PROF"
There are two modeling techniques:
First method. Use an fixed anchor at the point where the piping goes inside the heater. The heater vendor must provide the allowable loads for this anchor point. Or API 560 code may be used
Second Method. Model whole or part of the furnace coil that is inside the heater. Vendor should provide allowable displacements at the point where the pipe goes inside the heater (+dx, -dx, +dy, -dy, +dz, -dz). Usually it's the gap values between the pipe and heater shell
You can choose one of these two methods.
First method is very conservative. The loads on heater usually are very huge, but allowable loads are very small and can't be met. Element "Fired Heater" is used for modelling of heater using the first method.
Using the second method it is more easy to satisfy the vendor requirements. There's no need to model whole furnace coil, just 3-4 U-Tubes is enough.
The supports in the furnace coil should be modeled correctly.
The following conditions should be met:
Pipe displacements at the point where pipe hoes inside the heater should be less than vendor's allowables
All stresses both in the pipe and in the furnace coil should be less than allowable according to the selected code
Loads on the furnace coil supports should be less than allowables
Property |
Description |
Name |
Element name. If checked then it shown in 3D view |
Remove restraints for hanger selection |
If this option is activated, then some restraints are removed from nozzle element during weight run of variable and constant spring selection. During main analysis restraints are working. This trick allows to remove the weight part of loading from the nozzle element. Springs will take the exact load, at which displacements from pure weight load is zero. Options:
|
Type |
Tubes
Manifolds
|
Thermal Movement X,Y,Z |
The fired heater is modeled as an fixed anchor with thermal movements. These movements must be entered as input data |
Allowable Loads |
There are several options: no check, enter allowable loads manually and get allowable loads from API 560 code |
To insert a pump, select the desired node and use the menu option: Insert > Equipment > Fired Heater API 560
