Vent stack- Increase in flow rate

[Timetraveller007]

Hello Folks;

We have an existing standalone self-supported 30 in Dia x 40 ft length vertical vent stack with a pipe entrance at 45 degree to vent the natural gas to the atmosphere.

It is designed for 10 psig /180 F and supported by the foundation. The material is SA 516GR70N. The baseplate is 1.5 in thk.

Now client decided to increase the flow rate by adding more blowdown valves to the blowdown system.

With additional flow, we have found that we may see considerably higher thrust load due to venting applied to the bottom, and also we may see the dynamic load on the entrance nozzle.

We know that the flow won't be sonic at the stack tip so I don't imagine having any flow-induced vibration butI am not sure about it.

Now the question is that how we can assess the new flow and its effect on the mechanical integrity of the vent stack. How can we make sure the stack won't fail due to this additional blowdown rate and its additional forces and momentum.

Thank you for your help.

 

[LittleInch]

Please answer my questions I raised in your other thread. That's how it works here. We ask questions, you answer and then we can advise.

https://www.eng-tips.com/viewthread.cfm?qid=481049

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.