Will a Harmon Mag Stoker Burn My Size Bituninous ?

Some great info on the anthracite vs Bitum thread.. thanks guys. I don't have the choice out here to get anthrcite so I must use the bitum.
sooo...

I was at the Hearth, Patio and BBQ Expo last weekend in SLC and met with several of the R&D guys from Harman stove. Harman had several coal stoves going at the outdoor burn show and I was really impressed.
( I have not seen many caol burners so chime in if you have an opinion on stoves I may be unfamiliar with)
One problem we have here is that the coal is not as small as the eastern rice coal that they are using and designing for their stoves. In particular the Magnum stoker I was interested in , may or may not be able to burn the size bitumen coal we have her in the west. Our coal is thumbnail size and smaller .. down to pinky size thembnail.. It varies to size and we are not sure if the pusher ( no auger on the Mag Stoker) will jam. I wondered what your thoughts might be,
The magnum stoker does not feed from the bottom up IIRC... and I like that for ash cleaning. The Mag stoker pushed the coal to the burn plate and as it burns the ash ( clinker) falls to the pan. Right now we are using combustioneers coal furnace that augers the coal from below up into the burner. each day a huge clinker needs to be broken and removed. I'm hoping the Mag stoker will just fill the ash bin and no handling of the clinker needed.
I am sending a 5 gal bucket of our Bituminous to Harman this week for trial.
What I amasking is I want a stove that will burn the larger marble size coal and burn in such a way that I don't have a hard clinker to remove from the burner itself as in what we do now. By all means if you know of a better Idea or stove.. please reply.

Here is a link to the unit we use..
Our stoves are from teh 50's but similar to these. They are actually very efficient. Cleanup is a dog and they are not pretty to look at in a family room. Ok for a shop or basement I suppose..
http://www.peasefeedandcoal.com/Mountain-Man-85.html

all opinions appreciated.

you problems with clinkers stem less from the stove/furnace and design than from low Ash Fusion Temperiture (AFT) coal. I've personally burned coal from 6 different states and about 18 different mines as well as semi-bituminous met coal from germany. I can assure you that 99% of the time clinkers are a result of low AFT coal (usually with high pyrite content but not always). Basically every bituminous mine in the us has coal anylasis available. if you can't get it from them, go to a powerplant that burns it and ask them to see it, they generally will tell you all about the coal that they burn. I've burned low AFT coal and it really discourages one from using coal to heat. but just because the coal you are using behaves like that does not mean that coal from a mine 100 yards away will burn like that also.

Berlin wrote: I've personally burned coal from 6 different states and about 18 different mines as well as semi-bituminous met coal from germany. .

Berlin, have you ever tried any low ash West Virgina coal? The old specs on it looks excellent.

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Nope, I don't think I have, however west virginia has some very low ash semi-bituminous coals with outstanding BTU output.

the coal i'm currently using is basically the same as this one which was listed on that site;

Pa. Jefferson Co. Punxsutawney Mine; moisture:3.38 volitiles:29.33 Carbon:64.93 Ash:5.73 BTU:14,781

Hello, I ordered my first five tons of coal and had no idea of what it was I've signed up for or what quality of coal I'll be getting.

thanks for that site bjs 1779-gives me a little bit more of a clue as to what I'm after as a new owner of a coal burning stove. I'll go down in the basement and see what it is we've got and report in and see what anyone knows that they can share with this cold weather and coal burning newbie.

Berg - did you ever get a report from Harman on if the Bit coal worked in the Magnum stoker?

Steinke

The swelling and coking of Bituminous will clog up a Harman or other bed-type stoker in short order, I tried bituminous in a LeisureLine Pioneer... total failure.. the coal swelled and stuck to the sides of the bed, then the remaining coal piled up behind the stuck pile of bitum. Made a big mess.

greg L

Greg - I'd like you to be wrong on this one, though you seem quite knowledgable.

I don't think our Wyoming bituminous swells much. I also get zero bridging in my hand-fed. It burns quite clean, and only forms small clinkers occasionally. It doesn't turn "sticky" as some describe bituminous doing. Not really sure what that would even look like.

Our Harman dealer http://www.portersmvs.com/stoves/coalstoves.html sells Magnum stokers (as well as Mark III, TLC2000, etc), and I have a question into them on the feasibily of using these stokers for our coal. I'll post their opinion/experience when they reply.

I almost bought a used Leisure Line stoker from a person here in Wyoming. He said it burnt the coal fine, except that you had to scrape the tar off the ramp every few weeks or it would burn back into the hopper. But it fed across the bed fine. He said it burnt back into the hopper 3 times in the years he owned it. I didn't like that possiblity, so I let it go and built my own handfed. It's working fine (except for a few issues you've helped with). I can just see myself moving to a "girlie-man" stove if feasible someday. There are a few Leisure Line dealers around too, so it seems that some people must be getting them to work.

What I'm hoping is that the "verti-flow" design of the Harman would prevent burn-back into the hopper, since the coal is being fed from a point lower than the bed/fire. Does that differ from the LL stoves? Don't the LL stoves bring the coal onto the ramp from above?

Seems like Berg (who originally started this thread) isn't frequenting this forum anymore, so I'm on my own. I'm sure his coal in Utah? is different than mine anyway. I'll find out if other Wyoming Harman customers have tried it.

What makes the underfeed stokers like the Combustioneer work with bit. coal? Wouldn't the coal coming up into the pot swell as well? Or is there enough agitation/mixing action to keep the coal from clumping/sticking? And is the mixing what causes the clinkers? Could a stoker ramp be built for a Leisureline or Harman that had tapered walls, allowing the coal to swell without jamming the grate? Or possibly a mechanism under, beside, or above the ramp that mashed or rolled the coal to keep the bridging/sticking from occuring? Or how about instead of a flat bed with holes drilled in it, using a series of bars for a grate that the coal had to "bounce down"? If that's too much agitation, then what about building a revolving grate/bed that the coal dropped on? I'm full of questions aren't I?

Just some thoughts - feedback would be great.

Thanks,

Steinke

A correction above - the stove I almost bought that would occasionally burn back into the hopper was a Keystoker.

Steinke

May be of interest, Pre 1923 United States Coal Data. Wyoming is at the bottom of page.
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The underfeed stokers work well with bituminous for several reasons. One, the pot is tapered like a tulip, so the coal has room to expand as it moves upward during burning. Second, the gasses from the fresh coal pass through the hottest area of the fire and get mixed with air for more complete combustion. Third, the design of the units actually depends upon the coal ash fusing together into a clinker around the outside of the firepot to be removed several times (twice) a day with clinker tongs.

GregL tried burning bituminous in his Iron Fireman underfeed stoker (pictures in the "What does a stoker look like" thread, I believe. His experience shows a large "coke tree" forming out of the firepot. In reading through some old documents/magazines, I found that a coke tree is formed due to misadjusted air/feed rates - in this case not enough air. Fellow member HardWood has a Combustioneer stove, burning Ohio bituminous. Several posts here have pictures, etc. of his unit. He pulls out the clinkers several times a day, but otherwise has excellent results with it.

Pease Feed and Coal out in your neck of the woods handles some of the bituminous stoves.http://www.peasefeedandcoal.com I think they are in Powell, Wyoming. Unfortunately, the Stokermatic line of stoves is out of production at the moment, but Michael might be able to assist you. I've talked to him a few times and he's a good resource of information.

Building a stove/stoker will be quite a task, unless you're real REAL good with metalfab. I think an underfeed setup is the best way to go. Bituminous can be burned on an inclined, reciprocating grate made up of multiple stairstep sections that alternate between stepped and inclined (like an anthracite stoker), but that would be quite a project to design and build.

Good luck!

generally coals west of the mississippi will have a low swelling index, coals east the majority will be higher. so with enough air, you won't get any bridging.

Thanks berlin, I was hoping you had some info on this.

The big problem with bituminous is that it has such wildly different characteristics and still be a Bituminous coal. Some has very high volititles, high ash and high swelling index. Other Bitum is just the opposite, low volitiles, low ash and low swelling index. Getting the right coal can be a real gamble.

Since you seem to have a pretty good Bitum coal in Wyoming, with a low swelling index then a carpet type stoker may work OK. But your comment of 'scraping the tar off the grate' worries me. This 'tar' is what makes the coal stick together, so your coal does have the potential to get stuck on the grate.

Both the Harman and LeisureLine and Keystoker burn rice or buckwheat size anthracite, so can you get Bitum coal from a breaker in this small a size?? And it needs to be a pretty consistant size too.

Greg L

We can get coal rice and and buckwheat, but it is mixed with pea. They just call it "stoker" coal here. You'd end up screening it. I've been buying stove/lump coal for my handfed, but if they load you with a tractor, or even in the process of unloading, etc. you get some fines. I end up screening some of the small stuff anyway to remove the fines. My handfed has been handling rice and bigger OK, just can't add as much at one time with the rice coal.

I did get a reply from the Harman dealer regarding the Mangnum and bit. coal issue. He was not helpful. He just said he'd heard of problems and that the stoves were only rated for anthracite.

The tars on the carpet grate were from when the guy was burning sub-bituminous coal. We have access to some bituminous that I'm burning in my hand-fed. I'm not giving up on this issue yet. I asked the dealer a few more questions - we'll see what he says.

Thanks.

Steinke

even with a low coke button, and lots of air, it would be exciting, but doubtful that bituminous will burn with ease in a sliding bed stoker.

(btw, greg, i'm picking up that stoker 3rd of jan. and i'm damn excited, thanks for the tip! )