2 replies to this topic

[elham.n]

I've been checking a vendor design for fuel gas letdown station package. The let down is happening in two stages, and upstream of the second stage we have a heater as there is a requirement for the FG outlet temp to be more than 10 C. The heater is a shell and tube exchanger with FG on the shell side and ethelyne glycol as heating medium. Ethylene glycol is in a closed loop with a boiler/pump/expansion tank (similar to hot oil system). The only issue is that they are cascade controlling both glycol supply temperature and fuel gas outlet temperature by controling firing without having a variable like flow rate which in my opinion it wouldn't work.(correct me if I'm wrong) I proposed to fix the glycol supply temp and control the FG temperature by variating glycol flow through the exchanger. However our client thinks that we should control the FG temperature by firing and let the glycol temperature wander to whatever (no control on the glycol side). I'm not sure if our client proposal is a good way of designing the system or if it would work at all. your opinion is appreciated

[cea]

It is very difficult (& also inappropriate) for team members to visualize P&ID around heater section. It is  highly appreciated if you can attached vendor P&ID & your concern /  proposal in form of  mark-up.

[Bobby Strain]

Good engineering does not rely on opinions. But experience, expertise, and calculation.

 

Bobby