High temperature in scrubber

Good afternoon!
I have a question regarding on-line scrubber installed at exhaust gas outlet (metallic).
When the engine is running since hours, the scrubber is at high temperature (up to 200-300°C).
The design temperature is above so no problem on a mechanical point of view…

But when you start the scrubber (hundreds cubic meters per hour of cold water), do you think you will have issue due to very big temperature drop? we can have cracks or mechanical failure for example at nozzles.
I don’t have any example but if you have I am interested.
To avoid that, we have to start the scrubber then start the engine. If the engine is started, it is too late to start the scrubbers (we don’t want to have this big temperature drop). Do you ave an other idea or experience? Thanks a lot for your feedback.
Have a good day.

I agree with you that repeatedly quenching your hot scrubber unit with cold seawater could very well lead to a problem. What does the manual say about this? Is there a maximum temperature limit called out for starting up the scrubber? Will this be a moot point after Jan 1 when you’ll assumedly be required to operate your scrubber at all times? (I’m assuming you will be burning fuel with greater than 0.5% sulfur). If so, why not just run your scrubber continuously for the next 26 days as you will have to run it continuously after that anyway?

Don’t break your scrubber right before it’s about to be required.

He doesn’t mention if it is an open or closed loop, but open loop scrubbers are already being barred from use in many places. I don’t think you would be able to run them coming into or out of port areas.

Hello Louisd75 and Hawespiper.
This is a close loop. But the problem will be the same in open or close. When scrubber is hot, start water in the scrubber will decrease drastically the temperature>thermal issue and lots of constraints!
We have a procedure to avoid to start when scrubber is hot, but you know, a mistake can happen.
By the way, we don’t want to run it continuously because we have several scrubbers for several engines. This is to save electrical energy!

It sounds like these are generator engines you’re talking about? If so, why not start the scrubber for an idle unit, then start that unit and put it online. Then take the hot unit that was already running and shut it down / unload and idle it in order to meet whatever temperature requirement the maker’s manual calls for before starting its scrubber. All this would take some time and pre-planning of course.

Pay for kilowatts now or pay for off-hire / scrubber repairs later, it’s up to you. How are you going to avoid running it continuously after Jan. 1? What % sulfur fuels are you carrying now/will you be carrying after Jan. 1?

As you said:

so you should not intentionally violate that. If someone above you (Chief Eng./Port Eng/etc.) is telling you to do that, then I would want that order as well as your recommendation to not violate the procedure in email with appropriate people in copy. Print and save a hard copy of it afterwards…you’ll probably need it.

@Louisd75, this is a good point:

are you aware of a consolidated list of ports and whether they allow use of open loop scrubbers? I have been unable to find one.

I’m not sure of any list. I know that Singapore, Malaysia, China, UAE, Fujairah, and Panama ban open loops. The US leaves it to the states (for now) but the state of CA bans scrubbers regardless of the type and pretty sure HI bans open loop scrubbers. I think this would be within 12 miles though, unless I’m missing something (which is entirely possible).