Making Coke and Not Heat

LsFarm can give you tips to avoid making a lot of them, but they are pretty much a fact of life with bituminous. Anthracite however is pretty much free of it. You may want to try a half ton or so, longer burns, more heat and less hassel more than offset any cost difference.

"but they are pretty much a fact of life with bituminous"

no, they are not.

most of what he has there is coke. the orange colored ones look like a combination of rock, little bit of clinker, and coke.

with the larger sizes of coal, it is more common to find larger rocks mixed with the coal that look like clinkers, but often they are not. as was suggested above, try using less forced underfire draft, a deeper bed, and less secondary air, make absolutely sure that underfire air cannot escape around the coal bed, but must go through it.

More pics to help figure out what they are.... I also changed the forced air draft from the back of the firebox that was about 12 inches higher than the bed of coal to the middle where the screw manual draft was in the ash door. The orange spear color rocks are like a shale / clay rock and is very hard and will not break with your hands without a lot of force . pics are as follows:

more pics..you can only post 3 at a time..more to follow also.

and more

and more...

Last pics for now... The black plug above the blowers in the back of the furnace is where the forced draft was supposed to be placed per the furnace manufacturer. This stove came with a plug that can be removed to mount the forced draft blower. The blower was an optional feature that I had to purchase separately that hooks up to a thermostat. I had this hooked up per the instructions of the manufacturer and I was told by many people that the forced draft had to run underneath the coal bed to burn the coal correctly. After being told that...I took the manual screw type of draft off of the ash door in the front of the furnace and fabricated a plate to mount the blower where this screw draft was located as shown in the pictures posted. I replaced the plug on the back of the unit when I mounted the blower on the front so air does not enter from the top of the coal. I'm not sure if this helped yet due to the fact that I just hooked it up this way 2 days ago and only fired it up about 2 hrs. ago since the weather has been mild the past couple of days. So my question still is.........is this coke or clinkers???? If it is coke what can I do to remody this if it continues to happen??????

HI Rich, here is a clinker from my firebox, just removed this morning. It is four pieces, very light. It is melted together ash. The pieces were at the bottom of the firebox on top of the grate.

These are the result of a very hot fire, reaching the AFT [ash fusion temp] of the bituminous coal.

I think if you eliminate the secondary air above your fire, and have only air coming in under your coal through the grates, you will burn up most of your coal, especially if you make as deep a fire as possible,

Some of the lumps you photographed look like rock, this is not unusual, I have some every now and then. But the black partially burnt coal is just not getting hot enough long enough. A deeper hotter fire with only underneath air should burn it all up.

Greg L

Hello Greg,
The fire is burning very hot as far as I can see.... well into the 400 - 600 degree range on the stove pipe and gets the house up to about 68 degrees, but I'm not too sure how long it is burning this hot for due to the fact that I fire the furnace up at around 10:00 in the evening and by 12:00 midnight I'm in bed. When I get up around 7:30 - 8:00 there are still some hot cools, but not enough to re-start a coal fire and the temp in the house is in the mid to high 50's. I have to be at work at 9:00 so I don't have time to get a coal fire re-started so I restart with a wood fire and throw a big long on until I come home from work. In the evening when I get home from work at around 5:00 - 5:30 there is no fire burning anymore so I have to re-start from the beginning. I fire it up again with wood and then add a layer of coal. The temp is around 400 - 600 on the stove pipe. I then head over to my in-laws house until around 9:30 - 10:00. When I get home at around 10:00 at night the furnace is still burning / smoldering, and the temp is down to the 100 degree mark on the stove pipe and just enough cools to get a wood fire burning. So I get a wood fire started and layer it with a about 4 inches of coal and the process begins once again. I currently have the draft damper on the stove pipe open all the way which I'm not sure where to set it and maybe this could be part of my problem? I also have the thermostat on the front loader door set to medium. I know that in your previous post that you said to close the thermostat on the front door all of the way which I have failed to notice the first time I read it and just caught it as I was writing this post and I will do that first thing when I get home from work today. I will also get a good wood fire going and load the coal as high as I can in the firebox without going over the firebrick and see how this burns. How far open do you think that I should keep the damper draft on the stove pipe? Also should I sift the coal and just use the big lumps of coal or is it ok to just throw shovel fulls of lumps and fines in together? If you recommend just the big lumps of coal what do I do with all of the fines?

Thank you all for all of your help and patience!!!

Sincerely,

.....Rich

"about 4 inches of coal "

this is your problem, fill it to the top of the firebrick.

coaledsweat wrote:LsFarm can give you tips to avoid making a lot of them, but they are pretty much a fact of life with bituminous.

I found some really nice bituminous coal. They call it nut coal here. It is about the size of a golf ball or a tad bigger and it burns down to either fine ash or the granola looking ash. No klinkers at all.

It is ALWAYS hit or miss with bituminous coal, atleast around my area. But for the most part the stuff we get seems to burn well...

From looking at your pictures I would say you have a bad batch of coal. some of the "klinkers" you have are just simply rocks that you did not notice when you filled the stove. Most likely because they were covered with the other coal. The black pieces look as if you are not getting a full burn. I get those also, but I just let them in the boiler and they burn up.

I usually take a quick look at the shovel fulll and see if I can spot any odd or flat shapes. If you see a flat shape it is usually a rock. If you pick it up by hand and it is heavy, then it is a rock for sure...

Thank you all for the help....The coal is burning a LOT better now since I've closed the draft control(thermostat) on the front of the loading door and re-plugged the back where the forced air blower was first located, but I'm still having a problem burning the coal!!! First off after I have a nice red hot bed of cools I load the furnace as high as I can with coal as recommended and it starts to smoke alot and seems like the fire goes out. I close the loading door because of all of the smoke and open the ash door to see if the coal is still burning from underneath and what I see is a nice red glow. I then close the ash door and let the forced air draft from the ash door kick in to start getting the coal burning. after about 10 min I re-open the feeding door and still see no flames and just black smoke. I close the door again and another 10 min goes by and I hear a big bang and flames shoot out from the feeding door draft contorl(thermostat) and right after the flames shoot out a big puff of black smoke comes out of the same draft control( thermostat). After that I open up the feeding door and all I see is nice big flames and the coal burning very hot. I re-close the door to let it start burning. After about 4 hours of burning I check to see the status of the fire and what I see is all of the coal lumped and swelled together in one big fused together melted sheet. The top of the coal is not burning, but as I open the ash door underneath it is still glowing red. I then break up the fused together sheet of melted coal and then it starts to burn nicely again and continues to burn to ash until the next loading. Is this the burning of bad coal or am I still burning incorrectly?

Sounds like you are not banking the coal properly before reloading. You are not burning off the gases on the reload and the fresh coal is dampening the fire.

Hi Rich, what you are experiencing is exactly what I do when I burn nothing but Bituminous coal.

Bituminous cooks off a lot of volitiles, which is the black sooty smoke you see. You can burn some of this with hot secondary air, but it needs to be hot air, and this requires some engineering and fabrication. Just opening the loading door air vent will probably not burn off much of the soot.

The large sheet of fused black gooey coal is clasic Bituminous. I can make a similar sheet of coal on my firebox. I do what you are describing, let it fuse, then break it up an hour later to expose the edges of many chunks of coal to the flame and heat instead of just the bottom of the fused sheet or 'bridge' of coal over the fire.

The big 'bang' is also pretty much a regular occurance if you load the way you describe. To reduce or prevent most of the exposive gas/fumes ignition, leave an area of the underlying fire open when loading on fresh coal. The open hot coal area will act like a pilot light and ignite the gasses sooner and with less of an explosion. If you don't have the exposed 'pilot light' the gasses build up to large volume and wait for enough heat and a flicker of flame to ignite, with enthusiasm!!

Read this thread: The Stove 'Backfires'...Is This OK???

Then once the load of new coal is burning, add a few more shovels over the 'pilot light' area to fill it in.

Your Bituminous has a lot of bitumin [tars] and therefore sticks together. When it is burnt hot, it probably will fuse the ash together too. It's just the nature of Bituminous coal. These issues are why I spend the extra dollars and burn Anthracite as well as Bituminous.

Greg L

Check your PM's

the "bang" which to varying degrees is a fact of life with mid/high vol bituminous and I consider an automatic periodic chimney cleaner is normal and fine, one of the reasons however you want to seal stove pipe joints and put three screws in all of them. the coal swelling into a lump is a result of a. firebrick that doesn't insulate well and keep enough heat in the firebox to burn to burn away the lump on it's own. b. lack of preheated secondary air directed at the tars that form to make coal bed a solid sheet, but this is not always neccessary. c. extreemly high swelling coal. d. not enough forced air through the coal bed, the temp needs to be high to burn away the 'bitumin' at the top without secondary preheated air.

i'm not always a fan of leaving a "red spot" or "pilot" to ignite the initial gasses, because it is made of coal that is most of the way through it's burn cycle, you can have a spot that turns into a dead spot of ash in the coal bed alllowing underfire air to escape and not go through the fresh coal bed at all; especially with a coal that seems to be sticking together so well.

try doing as you did before, with the underfire fan air inlet all the way open so when it kicks on it's blowing as much air as possible, fill the coal bed tightly, and let it burn. while it will reach a point of least heat output around the time everything is fully fused, perhaps it will begain to burn through naturally, so wait it out, and report what happens.