2 replies to this topic

[chemest72]

I have to write a procedure on the re commisioning of a ammonia bullet. It is none refrigerated and a volume of 630m³. A hydrotest will be done where after we will purge the tank with N₂. I need some info on the procedure from the hydrotest to the filling of the bullet.

[pavanayi]

Chemest72,

Get the book 'Chemical and Process Plant Commissioning Handbook' by Martin Killcross.

[Art Montemayor]

Chemest72:

You require a pre-commissioning procedure as well. You have to prepare the equipment for a commissioning first.

Things I would note down as requisites (after the hydrotest) for a pre-commissioning and commissioning of a pressurized ammonia storage tank are as follows:

• Drain, clean, and dry the vessel – internally and externally;
• Purge with dry nitrogen if vessel is still humid internally;
• Confined space entry visual inspection ;
• Employ tank’s mechanical calculations and fabrication drawings to verify that the tank is in acceptable mechanical condition to safely withstand the designated MAWP and MAWV of the vessel; also confirm that if there are any revisions to the original tank fabrication drawings, these same revisions are backed up with acceptable engineering calculations and approvals;
• Install all nozzle pipe connections, block valves, instruments, pressure relief valves, and alarms;
• Check out and calibrate – if necessary – all instruments and PSVs;
• Apply a pneumatic pressure test to the assembled tank with nitrogen and test for leaks at all connections and gaskets;
• After complying with above, fill the tank with the initial quantity of liquid ammonia after evacuating the nitrogen fill;
• Ensure that the liquid level, temperature, pressure instrumentation is working adequately and accurately and testing all alarm points where possible;
• Turn over commissioned tank to operations with a sign-off document.

There may be items I missed, but this listing is subject to review and comments and should be approved by Operations.