How to remove rust in Steam Boiler (Marine Type)?

[rishirga1981]

We have steam marine boiler for one of our LNG floating vessel. We are experiencing some rust and looking some possible solutions or chemicals for removing the same rust.

Can you suggest us some possible solutions?

Attached are pictures for your reference.

Thanks

Rishi

 

[pmover]

it appears these photos are of the boiler fireside? exposed to atmospheric air when not in operation?
moisture collects when air temp drops to/below dewpoint temp.
to keep boiler metal at a temp above dewpoint, can a source of low pressure steam be brought to boiler steam drum to keep boiler warm? this will prevent moisture from collecting on boiler exterior metal surfaces. you will need to periodically monitor boiler water and possible treat before firing the boiler.
other ideas are to heat the air surrounding the boiler.
hope this helps and good luck.
-pmover

 

[chicopee]

Is this boiler in dry storage?

 

[rishirga1981]

Chicopee;

Yes, this boiler was in dry storage.

 

[rishirga1981]

pmover;

Thanks for your suggestions. Yes,attached pictures belong to inside the drum and it was not in operation and stored at side under ambient temperature.

I was thinking to clean inside with inhibited HCL before i put in operation. will it be fine or any further suggestions?

 

[StoneCold]

rishirga1981
In my opinion, it is a minimal amount of rust and I would just leave it there. If you try to strip it off with inhibited HCL you will probably end up with flash rust after you rinse the acid off anyway. Since it is minimal it should not affect your heat transfer anyway.

Regards
Stonecold

 

[chicopee]

A little late in responding due to other commitment. In dry storage the boiler should have been thoroughly dry and afterward trays of dessicant such as quicklime or silica gel placed in the steam and water drums. All connections should be tight, valves closed, handholes and manholes closed for the duration of storage. An alternate method is to have either a circulation of dry air or the introduction of an inert gas pressurized in the boiler.
I agree with StoneCold with the surface rust appearance which you can maintain as is with the procedures outlined above until such time that the boiler is ready for startup, then the chemical treatment should be able to remove that surface rust.
About the fireside, how did it look?