Recently I had the pleasure of working with a client on a PHA project during which we came across another excellent example of how “start-up’s” can be very different from the “normal start-up” procedure. I like to bring these examples to our attention as we still hear this all the time… “our initial start-up/normal start-up/start-up after ESD, etc. are all the same“. This is a perfect example of how some “start-ups” can be very different…
The NH3 process unloads trucks/railcars using vapor from the storage tank(s) to pressurize the tanker truck or railcar to move the liquid to the storage tank. This vapor is moved using a compressor to pull the vapor from the storage tank head space and push it to the transport container. Using the compressor(s) meant that all of the safety alarms and interlocks were functioning.
This past shutdown, the storage tanks were emptied for their internal inspection(s). As the shutdown was wrapping up the team wanted to begin filling the NH3 tanks to ensure ample inventory for start-up of the units. There was just one slight problem… with the tanks empty there was no NH3 vapor to use to pressurize the transport containers. The facility did not have an SOP to unload a tanker truck using the trucks pump and this practice would negate all of the safety systems, since they were all tied into the unloading compressor(s).
So as we can see, start-up after a shutdown/turnaround can be very different from a normal start-up. The question was also asked… how was the initial start-up/unload performed?