What beats hastelloy for sulphuric resistance?

[YungPlantEng]

This is a goofy way to state the question but I’m getting one of our hastelalloy C276 nozzles analyzed for corrosion mechanisms, validation of material, and to hopefully get some directions on ways to limit the component mtbf.

The service is 2000 F SO2 into a quenching unit. The theoretical chemistry our refractory company has is that sulphuric acid forms and attacks the nozzle when eddy currents push it back up into the nozzle. There are also thoughts that carryover sulfur quickly removes the oxidation layer preventing any meaningful component lifetime. Since this is a high temp, high flow, sulphuric service I can’t for the life of me find any materials outside of maybe C-22 that might be comparable. We’d be willing to spend 3-4x the cost of the nozzle on a custom solution if there is one.

The issue is that as this nozzle abrades the refractory is directly attacked leading to a 4 month nozzle replacement and rebuild period. Curse the engineer who made this degenerate process but has anyone had experience with finding a big brother to c276?

 

[MintJulep]

If the theory about eddy currents is correct then possibly a different geometry could prevent the upstream flow.

 

[TugboatEng]

2000 degrees? Have you not considered ceramics?

 

[EdStainless]

Ceramic is the way to go.
I would talk to Blasch and CoorsTech.

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P.E. Metallurgy, consulting work welcomed

 

[YungPlantEng]

We already utilize a SiC ceramic that’s set in place by a cad table pour. This nozzle is used to direct the flow and sits inside that ceramic.

Im not sure on the reason behind us not using a ceramic for the nozzle itself, it might be that we either couldn’t find a way to tie the ceramic into the rest of the system or there was too much vibration and the ceramic would fail early on.

The specification for a metal nozzle was originally done by the refractory/burner company. I don’t know if we can easily trial other options since a release in that section could be catastrophic. I wanted to look into C-22, C-2000, BC1, etc but the corrosion effects at high temperature aren’t well understood

 

[TugboatEng]

If geometry restricted the use of a ceramic insert in the past, there is additive manufacturing of SiC now.

https://www.sglcarbon.com/en/markets-solutions/material/sicaprint/

 

[dik]

I agree ceramic could be the way to go.
Among the elite C alloys I would prefer Alloy 59 for its better stability.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."