My EFM WCB24 Hand-Fired Boiler Was Wasting Coal

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stoker-man
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Location: Lehigh Valley, PA

Post Sat. Mar. 14, 2015 6:45 pm

Usually in the Fall, I buy 3800# of nut coal, the capacity that will fit into my trailer, in one trailer load, at about $220 a ton. That usually lasts for Dec., Jan., and Feb. for heat and domestic hot water. Before and after those months, I burn wood in the boiler for hot water only and use my wood stove inside the house for heat. This year, because it was so cold, I ran out of coal in the first week of January.

Just my luck, my lane was solid ice and the coal dealer's lane was also icy, and on a hill, and snow was coming. Forget about pulling a trailer in ice and snow, so I called him up and asked how much to deliver a ton of nut. He said $260 a ton. Ok, so how much for two tons? $260 a ton! Thinking that he's only a mile away, why is he charging $80? So, I'm not happy, but I ran out of wood, and I had to eat that $80 charge. There won't be a next time.

I had been throwing the ash on the lane and I noticed that when the snow melted, there was mostly unburned coal. I wondered how the entire bed of coal in the firebox could be glowing orange, and burn out, and there still be so much unburned coal. The useless shaker on these boilers jams up with the first piece of coal that tries to fall through, so I use a long length of 1/2" water pipe to ram through the bed and to lift it to get most of the ash out.
coal on the driveway.jpg
Unburned coal on the driveway
I thought I would try filtering the ash bins through some 1/2 X 1/2 hardware cloth and picking out the larger pieces of clinker and reburning it again. Turns out it's easier than I thought. Only takes a few minutes per ash can. I wasn't sure if the mixture would burn, but it burns great and can be added to unburned nut coal or burned on its own. Whatever falls in the ash can gets sifted, so, in essence, even the previously filtered coal, gets filtered again.
Sifted coal.jpg
Sifted coal with a few large clinkers picked out
In the next picture you can see the amount of ash from about 10 days of burning during cold weather. There is about 1 1/2, 5-gallon buckets of clinker from that amount of ash. I am switched over to wood again, so I'll have to wait till next season to see how much savings there will be.
coal ash in the cart.jpg


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Lightning
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Post Sat. Mar. 14, 2015 6:54 pm

stoker-man wrote:In the next picture you can see the amount of ash from about 10 days of burning during cold weather. There is about 1 1/2, 5-gallon buckets of clinker from that amount of ash.
So you are saying you screened out 1.5 buckets of material from 10 days of burning. Is the 1.5 buckets just clinker material (fused ash) or is it partly unburned coal that fell thru the grate?

How much reburnable coal did you retrieve from the ash?

Also, how much coal did you burn during that same 10 days. Did you track it somehow?

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stoker-man
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Post Sat. Mar. 14, 2015 8:35 pm

Returnable coal includes some clinkers I don't pick out, such as what you see on the screening. The stuff on the screen gets reused. I reuse probably close to 50% of the raw ash. The 1.5 buckets of clinker, plus the ash in the cart, are all that remain after about 10 days of 24 hour burning. The amount of days are a close guess. I didn't do this test scientifically and I think I'm done with coal for this season, so I can't continue with the test.

As far as the amount of coal I use each day, I would add at least 4 shovels, 4 times a day. That's about 3, 5-gal. buckets a day for the last week of Feb/first week of March.

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stoker-man
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Post Sat. Mar. 14, 2015 8:55 pm

I just measured the size of the ash bins. They hold 800 cubic inches of ash (23 X 7 x 5). What you see is the usable waste from one bin. The amount of reusable coal from 4 bins filled a 5 gal. bucket to the top. I did it yesterday, so it's fresh in my mind.

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Lightning
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Post Sat. Mar. 14, 2015 8:56 pm

stoker-man wrote:That's about 3, 5-gal. buckets a day
OK, just trying to help see if the amount wasted coal is worth all the extra effort. SO, 3 buckets x 10 days (give or take some) = 1.5 buckets of stuff salvaged from the ash. Of that stuff, it appeared to me that about half of it is healthy BTU producing coal the other .75 bucket is just fused ash and isn't gonna help BTU production at all.

Lets convert it to pounds.
30 buckets of coal used we'll call 1200 pounds.
.75 buckets of coal we'll call 30 pounds.
Your lost coal amounts to only 2.5% of what you put into it.

I've also calculated my lost coal in ashes to run about 3-5%
so I think yer doin pretty good... I wouldn't loose sleep over it.. :)

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Rob R.
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Post Sat. Mar. 14, 2015 8:57 pm

Something seems amiss. I have never seen that much coal in the ashes of a hand fed. Your shaking technique must be knocking a lot of unburned coal through the grates.

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Lightning
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Post Sat. Mar. 14, 2015 9:01 pm

Rob R. wrote:Something seems amiss. I have never seen that much coal in the ashes of a hand fed. Your shaking technique must be knocking a lot of unburned coal through the grates.
stoker-man wrote:I had been throwing the ash on the lane and I noticed that when the snow melted, there was mostly unburned coal.
Rob, I suspect that some rain and snow melt have washed away a great portion of the fine ash exposing the unburned coal in his driveway. IMHO - It gives a missed impression of a lot of coal is going out the ash pan..

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stoker-man
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Post Sat. Mar. 14, 2015 10:01 pm

Hold on. The 1.5 buckets of clinker and what you see in the garden cart is what's left over after the 10? days. The amount that you see on the screening is reused and is from 1 ash bin.


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Lightning
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Post Sat. Mar. 14, 2015 10:13 pm

OK.. Sorry I assumed it all was from 10 days of burning.
I'm confused now.. :? Carry on.. :lol:

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Lightning
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Post Sat. Mar. 14, 2015 10:22 pm

stoker-man wrote:I just measured the size of the ash bins. They hold 800 cubic inches of ash (23 X 7 x 5). What you see is the usable waste from one bin. The amount of reusable coal from 4 bins filled a 5 gal. bucket to the top. I did it yesterday, so it's fresh in my mind.
The 1 bucket of reusable coal is from the 4 bins of ash which = 10 days right? 30 buckets going in?

OK.. I get it now.. I hope. :lol:
30 buckets = 1200 pounds
1 bucket of burnable coal salvaged from ash = 40 pounds.

That's still only 3.3% usable coal lost in the ashes, which is reasonable, isn't it? :)

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SWPaDon
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Post Sat. Mar. 14, 2015 10:50 pm

I'm using bituminous coal and have almost 0% unburnt coal in my ashes. I think I've lost just about 1 cupful of coal in the ashes all season.

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Lightning
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Post Sat. Mar. 14, 2015 10:58 pm

SWPaDon wrote:I'm using bituminous coal and have almost 0% unburnt coal in my ashes. I think I've lost just about 1 cupful of coal in the ashes all season.
My anthracite supply has a lot of small pieces. Even though I ordered a nut/stove size mix it has a considerable amount of pea all the way down to rice and barely in it. Which is fine with me, it tends to sort itself somewhat when its poured into my bin. So on low slow burns I use the small coal and for high demand I use the bigger sizes. Anyways, the small stuff tends to fall thru, anything less than pea size that doesn't burn before shake down. Plus my aggressive tending routine of raking and heaving helps promote some loss too :lol:

I noticed when I burned bit I didn't hardly see any lost coal also..

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SWPaDon
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Post Sat. Mar. 14, 2015 11:17 pm

The one load of coal I got was the 'run of mine' and about half of it is the consistency of sand. That stuff will smother my fire if I'm not careful. I've got to leave a good layer coals in the furnace to keep it from falling through the grates.

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stoker-man
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Post Sun. Mar. 15, 2015 10:45 am

SWPaDon wrote:I'm using bituminous coal and have almost 0% unburnt coal in my ashes. I think I've lost just about 1 cupful of coal in the ashes all season.
If bit was available in eastern PA, I would use it. I did experiments with bit running in the efm stoker and it worked great. Getting the correct size coal was the only problem.
Lightning wrote: Plus my aggressive tending routine of raking and heaving helps promote some loss too
This aggressiveness is also necessary in my boiler if I want the fire to breathe and also why I lose pieces out the bottom.
Lightning wrote: The 1 bucket of reusable coal is from the 4 bins of ash which = 10 days right? 30 buckets going in?
The one bucket of recycled coal is what I gain after sifting 4 ash bins, which hold 800 cubic inches each. So, 3200 cubic inches of ash, once sifted, leaves me one 5-gallon bucket of reusable coal mixed with small clinkers. Remember that the ash I sift contains recycled as well as ash from new coal added at the same time. The effort to sift the ash only takes a few minutes. In past years, I would dump large quantities of ash on my property and cover it with topsoil and plant grass. This also makes life easier for me in addition to recycling.

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Rob R.
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Post Sun. Mar. 15, 2015 10:46 am

Why don't you use the existing shaker grates? Jams? How often were you shaking the coal bed?


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