What causes Ash to cake up

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captcaper
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Post by captcaper » Mon. Feb. 27, 2023 8:27 am

When the temps go way down and the stove is working hard to keep up the Ash cakes up and doesn't fall into the pan as when the temps are more milder. The caked Ash will flow straight off the grate into the door then back up the rest coming building up after a while to were the red coals are very thick and in our extreme cold we had this winter new fed Rice was pushed over the sides just before the Red burning coal.
I find in these fridid temps I'll go down every few hours and knock the caked ash heading straight out so the burning coal doesn't pile up again and repeat the problem.
I guess if the door on this Super Mag was further forward from the grates the ash would drop on it's own.

 
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Rob R.
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Post by Rob R. » Mon. Feb. 27, 2023 8:41 am

When you approach the ash fusion temperature, the ash will clinker into the “cakes” you described. Coal with higher iron content is more prone to this, and running at high output is typically when you see it.

About all you can do is back off on the feed and air until the ash doesn’t clump, or try different coal.

 
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davidmcbeth3
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Post by davidmcbeth3 » Mon. Feb. 27, 2023 12:52 pm

There are research papers online about examining ash fusion temperature.

Essentially, the ash ends up forming crystalline formations due to processing conditions.

I would guess that a cure would be to add something like potash to the coal prior to entry into the fire. The cure is worse than the disease I would think. Turning your ash into a hazardous mix that would require it to be handled and disposed of as hazardous waste and quickly eating away your device.


 
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captcaper
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Post by captcaper » Mon. Feb. 27, 2023 4:11 pm

Got it. thanks.

 
LehighanthraciteMatt
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Post by LehighanthraciteMatt » Tue. Mar. 21, 2023 2:11 pm

Very few times is Anthracite going to "fuse". Ash fusion temperatures for Anthracite consistently reach temperature of +2800 degrees. You may get caking due to the stove running too hard. The stove was designed for a btu output. when you exceed this output by "overfiring" the stove, the coal is getting more air than it should. It can in turn slightly melt the carbon and cause the ash to "clump" or "cake".

 
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freetown fred
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Post by freetown fred » Tue. Mar. 21, 2023 2:44 pm

Thanx Matt!!!:)


 
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Post by coalfan » Tue. Mar. 21, 2023 3:18 pm

yes thanx matt good info. !!

 
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Post by captcaper » Sat. Mar. 25, 2023 7:46 am

LehighanthraciteMatt wrote:
Tue. Mar. 21, 2023 2:11 pm
Very few times is Anthracite going to "fuse". Ash fusion temperatures for Anthracite consistently reach temperature of +2800 degrees. You may get caking due to the stove running too hard. The stove was designed for a btu output. when you exceed this output by "overfiring" the stove, the coal is getting more air than it should. It can in turn slightly melt the carbon and cause the ash to "clump" or "cake".
Thanks. That would be my stove. It works hard in this home with temps falling well below zero or near zero often. But mostly it does okay. I've learned to watch the stove during those times or turn the oil furnace on to make the Harman relax until outside temps return up some.

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