Start Up of Propane Vaporizer

[2ply]

I was wondering in anyone has experience with the start up procedure of propane vaporizers. I have an issue with the heat load at start up. The vaporizer is for 25000 kg/hr super-heated propane @ 25 bar. LP steam is used as heat transfer input with condensate side control.
Start up load seems to be very load for this...Peak load is 4.5MW and start up has a very small load plus gas sent to flare.... How is it usually done?

 

[georgeverghese]

That is a challenge on all heat exchangers; havent seen any one compensating for tube bundle metal heat in heating controls. Another way to manage this is to install a buffer volume vessel between the vaporiser exit and the turbines to allow for (a) tube bundle heat to dissipate on large demand chnages and (b) account for other response lags in the PC control loop.

The level controller on the propane in the shellside could reset a level recycle valve around the pump (on a fixed speed pump) or reset pump speed on a VFD drive.