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Ash from coal fired boilers

gab.riels

Member
Joined
Jun 20, 2025
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5
I've been running some combustion trials all week on a mid capacity coal fired boiler, its bituminous blend, mostly high volatile B rank, and part of the trial is going towards me trying to get a better handle on ash behavior under different load conditions. We're seeing a mix of bottom ash that's coarse and granular, but the fly ash is all over the place, can be fine and fluffy sometimes and other times a bit sintered and sticky, and its really messing with the ESP efficiency.
I'm particularly interested in how different furnace temps and coal blends are affecting ash fusion temps and composition, especially tracking calcium/silica ratios or measuring T250 softening points lately?
Thoughts please, thanks in advance
 
For the fly ash variability, beyond just furnace temp and coal blend, have you looked into oxygen levels and excess air through the different load conditions? Sometimes subtle shifts there can surprisingly impact the fly ash morphology and stickiness, even with the same coal. Regarding Ca/Si ratios and T250, we've had good luck correlating those with ESP performance, especially when there's a noticeable change in the slagging or fouling. Keep an eye on the iron content too, as that can also play a significant role in lowering ash fusion temperatures.
 
I've been running some combustion trials all week on a mid capacity coal fired boiler, its bituminous blend, mostly high volatile B rank, and part of the trial is going towards me trying to get a better handle on ash behavior under different load conditions. We're seeing a mix of bottom ash that's coarse and granular, but the fly ash is all over the place, can be fine and fluffy sometimes and other times a bit sintered and sticky, and its really messing with the ESP efficiency.
I'm particularly interested in how different furnace temps and coal blends are affecting ash fusion temps and composition, especially tracking calcium/silica ratios or measuring T250 softening points lately?
Thoughts please, thanks in advance
I guess just keep logging those Ca/Si ratios and maybe run a few samples through a muffle furnace to watch softening trends.
 
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