Cleaning of the finned tubes on gas cooler without disassembling

[Optymista93]

TL;DR Summary

Methods and ideas for cleaning a gas cooler without the need of disassembling.

Hi,

I've been thinking about the solution for cleaning a water-cooled gas cooler and would love to hear some advice from the smarter people with more experience.

Description - I will try to roughly explain the concept.
Gas Cooler is used to decrease exhaust gas temperature. The exhaust gas temeprature is usually between 450-700 deg C, so You get relatively clean exhaust gas. Water/glycol mixture is used as a coolant.
After some time the exhaust gas builds up a deposit layer in form of soot on the tubes surface, fins and inside walls of the cooler (thermophoresis). This has a great impact on thermal conductivity and leads to less efficent cooling and backpressure built up.

It is time-consuming and not user friendly to disassemble the cooler and involves work disruption.
There are few solutions I've thought about to partially remove the soot inside of the cooler without disassembling:

1. Mehanical: by water vapor or a mixture of water vapor and some chemicals that increase removal rate of deposit layer.
2. Chemical: by powder that decreases melting temperature of soot (soot remover).

You will still need to dismount it from time to time and flush it clean, but you increase the operational time without need of disassebling.1. Mechanical solution
Breaking it down into small pieces from the engineering side. If I inject the water inside of the exhaust chamber it will almost instatnly evaporate and will be taken further with the gas flow, partially cleaning the soot deposit. The question is how much and at what rate do I have to inject the water to make it evaporate. If I inject too much at the time, I might end up in situation where not all the water evaporates and lays down on the hot stainless steel surface at the bottom of the cooler. This will likely damage the surface and lead to a leak. If I have the gas flow rate and temperature available, wouldn't it mean that I can somehow calculate the inside diameter of the tube/ lance that have to be used in this case? I would prefere to use a drain port(s) as a placement of the water lance. This way, I could connect the water to the drain port whenever is needed and avoid introducing completely new design (backwards compability). How would you approach this?

2. Chemical solution
This is a known solution. I could for instance use this soot cleaner(Link) and connect directly through drain port.Thanks for all the suggestions.

 

[Lnewqban]

Could you have steam to be injected rather than water?
It seems to me that that flashing could increase internal pressure too much.

 

[Optymista93]

Could you have steam to be injected rather than water?
It seems to me that that flashing could increase internal pressure too much.

Thanks for the answer Lnewqban. Yes, I'm thinking about steam, but You don't always have actual steam easily available at the site. Water is way more accesible. You could potentially use some form of a small "steam generator". You already have exhaust temperature acting as a "burner".

Flushing is only viable when the engine is not operational. You have to do it from time to time, as steam won't be able to remove all of the deposit layer.

 

[Tom.G]

https://www.internationalusedtrucks.com/how-to-clean-a-dpf-filter/

(above found with:
https://www.google.com/search?hl=en&gbv=2&q=how+to+clean+diesel+exhaust)

 

[Optymista93]

https://www.internationalusedtrucks.com/how-to-clean-a-dpf-filter/

(above found with:
https://www.google.com/search?hl=en&gbv=2&q=how+to+clean+diesel+exhaust)

Thanks for the suggestion Tom, however this won't be exactly as easy as active/passive DPF filter cleaning. Active cleaning is present at all times, when the exhaust temperature is sufficient. Passive cleaning won't be an option, as we have restrictions to exhaust outlet temperature. (By injecting excess fuel, we would increase exhaust temperature.)

English is not my first language and I guess I didn't state my question well enough. I'll try again.
I want to use water on site, as it is easily available, to create steam and inject it to gas cooler in order to remove some part of the soot deposit layer. Any ideas on how to approach this?To visualize it better for You, here's a sketch of gas cooler.

 

[Tom.G]

Perhaps a spray head (or pipes with holes drilled in them) in the exhaust stream before the cooler. But that is essentially what @Lnewqban suggested above.

Combining ideas, some pipes in the exahust stream to generate steam feeding the sprayers. That way you may avoid overpressure in the gas cooler.

Cheers,
Tom

 

[Rive]

Maybe you could just blast it?
A 'kiln gun' would be kind of an overkill (), but something along the principles of 'shotgun starters' would produce enough mechanical impact to clean the tubes...

 

[Optymista93]

Thanks for all the suggestions, they're all much appreciated!
I think I'll go forward with chemical solution nevertheless. It's the safest and already tested method that doesn't involve exposing high temperature steel to potential water condensate, which can lead to development of cracks. I'll let you know how it went, when I've tested it!