Burning Coal in a wood furnace and stove

Hello, Before I write anything please be aware I am wet behind the ears with this. Okay.. Here we go..I have a 50 year old wood furnace it is lined with firebrick. I ran out of seasoned wood and I was freezing so my friend said he had a whole room of coal still that I could have. So Ive been burning it, incorrectly i know now. I understand the air has to come from underneath the coal. I installed a draft blower on the front of the furnace to help with the wood when I was burning it . If I just left the ash drawer slid out a little bit and sealed off the blower would it burn well? Should I leave the drawer slid out and run the blower? I've been thinking about welding a stainless plate to go inside the firebox in front of the draft blower to divert the air into the ash drawer. Any suggestions would be appreciated.

I also have a Kindlewood stove upstairs that says right on it that it burns coal and wood. However the air intake is still above the coal. Is there a grate that is sold somewhere to raise the coal that I'm Missing?

Thanks in advance, Justin.

Links,

Glad you came on over to this site. I have already pout my 2 cents in towards your problem. SO, I will let others here take a shot.
The Kindlewood stove you have that says it burns wood and coal is probably made to mostly burn wood ( since the combustion air is above the fire) but is built heavy enough to allow coal burning. Raising the coal would only be of minimal help since the air still needs to come up through the coal. Could you possibly post a pic of the front of bothof your stove and maybe the grate sytem also?? That would REALLY help to figure out if your stove would allow the proper burning of coal.

Thanks KTM, Here is a pic of the furnace I know Its all rigged up but if i can just finish off the winter with it I would buy a new stove for next year.

Hello Links. welcome to the forum.. We need to see the grates and the firebox in the furnace..

Do the grates on the bottom of the firebox move with an external handle. These are 'shaker grates'. You need this type of grate to get the coal ash to drop down into the ashpan.

If you remount the blower on the ashpan door, and plug the hole where the fan is now, then you may be able to get enough air under the coal and up through the grate to get coal to burn in the furnace.

Take another photo of the firebox, showing the grates if you can.

What type of coal are you trying to burn? soft coal [bituminous coal] or hard coal [anthracite coal] ??

Greg L

Well theres coal in there now, even though it doesn't burn right it still keeps me from freezing completely. It doesn't have a shaker grate. It has some pieces of rebar welded into it for a grate. I was gonna make some sort of shaker grate if I could make it burn better. Then there is firebrick on each side it makes a V. This is all I have for heat. I am burning "stoker" coal whatever that is classified as, Its small pieces like an inch by half an inch or so, Please bring me up to date on whats what I'm still learning. Natural draft wouldn't be enough to make it burn correctly if I left the ash drawer open plugged the blower hole, it wouldn't suck air in through the open drawer through the coal then out the chimney? If I moved the blower and welded the hole shut would I still be able to burn wood using the blower? Thanks for all the knowledge and wisdom guys. Links.

Heres The kindlewood stove.

Most stoker units use Rice or Buckwheat (3/8"-5/8" in size). NOrmally with hand fired type stoves, you need more airflow, so you should use larger type coal (Nut, Pea, Stove, etc..). Looks like you need more air flow which if you use larger coal, it might work better.

Other hand fire users should be able to help you out....just my 2 cents...

Stoker coal is a name for Bituminous sized coal. So I suspect you are burning coal from southern Ohio, West Virginia, Kentucky etc.
Bituminous coal burns different than Anthracite coal. Read some of the threads on the Bituminous forum.

Greg

Thanks greg!! I need to brush up on my terms then....

actually I am burning coal that was mined in Alpha, ILL. The reason I am burning it is because Its what my friend had left in his basement from his stoker furnace. Its the only kind you can buy within 100miles of me, and its 90 bucks a ton! I couldn't believe it you used to be able to get coal everywhere but now i can find one spot in Kewanee, ILL.Thanks, Links.

I mounted the blower on the ash drawer and its burning great!! Except it smokes like a freight train outside and I have already had the cops and fire dept. in my house because of it. They said I didn't do anything wrong and it was just some whiny neighbors. Is there any way to reduce smoke output? thanks, Links.

As far as the smoke problem. I will take a shot. It could be the creosote burning off from burning nothing but wood for an extended period of time. If that is the case, i would keep a REALLY close eye on the chimney. You could have a chimney fire brewing.. Remember, coal burns ALOT hotter than wood.

If you just added your coal to a really hot fire, sometimes the volitiles in the coal will smoke alot for the first 5 minutes or so but then you shouldn't see any smoke at all.

Or, if you are mixing coal and wood, the wood gases aren't burning all that well since your combustion air is now coming from under the fire..

first off, southern illinois bituminous has some of the highest volitile content of any coal available in the usa, so you're going to have some smoke when burning it in a batch fed furnace, this can be mitigated in several ways, none of which are simple and none will completely eliminate it.

i would like to see pic's of the smoke produced from you chimney, to see whether it may be excessive or something you may be best off leaving alone for the sake of simplicity. the only real concern then becomes whether you are close enough to your neighbors for it to surround their homes and them to smell it, and if not, then it's not really a big deal. One of the main reasons to install secondary combustion preheated air, is NOT simply smoke reduction but a reduction of the swelling and fusing of the top of the coal bed, southern illinois coal is not a coking coal so this is really nota concern. you would obtain about 10-20% more heat out of the coal with such aperatus installed however the fact that you have free coal, and possibly live far enough away from your neighbors to where the smoke is not a nusance really doesn't make it necessary.

yeah, I live far enough away it was just so windy last night some 40MPH+ winds. I will see if I can get a picture or two of the smoke today. Can you describe What "coke" is? Im new to this. Thanks, Links. How much coal would one usually need to get through the winter with a 1000 sq ft house? I must have about 10 tons or so that is free. You can buy it around here about 100 miles away in Kewanee for $90 a ton, is that reasonable for stoker bit?

A properly burning stove, not an insert should burn about 3-5 tons of Bitum for a season. You may not do as well with your furnace, some heat is wasted when the fans are not running, I'm not sure if you have a constant running fan or thermostaticly controled.

So you should be fine for this season. You will have soot issues with that high-volitiles coal... Soot, from the unburnt volitiles will attach itself to the inside of the upper firebox, heat exchanger, and inside the flue and chimney. You may find your draft diminish over a few weeks, and you will have to clean the chimney often.

Coke, is bituminous coal after it is cooked by the fire, but the coal hasn't burnt up yet. The volitiles are all burnt off, what remains is almost pure carbon.

Read up on the burning bituminous threads. Each mine or regional area's bitum coal has different characteristics.. Some have high volitiles, and make huge volumes of smoke, some has high swelling index and will get soft, sticky and swell up when heated, each piece sticking to the next, making a hard bridge or crust over the fire below. Some bitum has very high ash content, seems to fill the ash pan in 6-8 hours, etc... Some bitum is really nice, very near anthracite to burn, some is really nasty,

Let us know how your luck is going with the coal.. remember a deep coal fire is happy, a shallow fire will go out easliy. make the coal bed deep, shovel it in till it is up to the top of the firebricks, and control your heat output with the combustion blower fan and under-fire draft controls.

Greg L