Auxiliary Boiler pre-operation tests

Hello,

Can you suggest some recommended pre-operation tests in an oil tanker, in order to ensure proper operation of boilers during discharging?

Aside from all the safeties that we would check anyway, I would look into what historically causes failure for that particular boiler model. Of course, crews don’t usually report minor issues, so maybe ask around. In my experience, control system issues are the worst as they are unpredictable.

I would clean the burners/ignitors before operation and check feedwater control valves for smooth movement (no sticking). We also used to clean the screw-type flowmeters on Aalborg boilers before operation, but most ships have the Coriolis-type now.

I would also postpone any unnecessary maintenance that comes up in the days before discharging. There is an opportunity to perform tests and have a good look at your system in order if the vessel has to top up IG before arriving.

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@jstat’s points are practical and good.
I would also add:
Test the feedwater quality and especially the chlorides concentration on both boilers and the cascade tank. In case of high chlorides concentration, investigate the root cause proceed with repairs/plugging and blowdown and/or replenishment of boiler water
Check the operation/response of all boiler controllers (water/air/fuel) in manual mode.
Run both auxiliary boilers with 50% load each, in parallel (one cargo pump in operation + steam damping valve). During that test, the following checks are recommended:

  • Run all the feed water pumps one by one to check/ compare their discharge pressure and motor electrical current(A)
  • Run all boiler fuel oil supply pumps one by one to check / compare their discharge pressure and motor electrical current (A)
  • Operate one boiler in “emergency mode”.
  • Check/compare the remote feed water level indication with the local sight glass (they must be the same)
  • Perform water level control using the local boiler valves (manual mode).

Somebody could argue that considering the amount of fuel consumed, the above is an “expensive” pre discharging check.
However, the possible off-hire costs as well the damage in the Company’s reputation will eventually have a greater financial impact.

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