This coal was “a first” among the Bitiminous I’ve tested. It is a blend of 50% Kentucky stoker and 50% Ohio Brookville high sulfur and was supplied by our site moderator Berlin.
It didn’t break easily in the forklift and steel plate breaker like the other types of Bit; it was a lot harder. As supplied, about 70% fell through the ½” X ½” hardware cloth, but the oversized 30% was difficult to break. The coal was cubic in form. The cubic shape and large size caused the coal to bridge over the feed worm twice during the first day’s test. A normal feed worm extends outside the pipe 8-10”, but our test bin only allows the worm to extend about 1” outside the pipe, which is some of the problem.
The hardness of the coal and large size caused a lot of crunching in the feed pipe and strain on the gear drive. Using the maximum air supply, I couldn’t burn at a continuous feed rate above 7 teeth because the coal was too large and hard. If the coal was closer in size to rice coal, on the left, I think all the problems would disappear.
The smoke from the fire ranged from minimal to slightly visible. I think smaller sized coal would produce minimal smoke. For you train buffs, enjoy the old Conrail engine at our crossing.
This is an established fire. If you look closely, you will see that each turn of the auger brings up new coal from the bottom and tends to break apart any forming clinker and I believe this is why there has never been a bituminous clinker problem in any of the previous tests. The resulting ash is very similar in size to anthracite.
The unit was shut down and allowed to rest for 70 minutes. There was no problem with the fire going out. The temperature outside was about 90º and inside it was 93º and the draft was minimal at .03 negative. This picture shows the fire after 70 minutes rest.
The stoker was turned back on after 70 minutes of rest and the fire easily resumed. Note how the ash crumbles.
The coal fire did not hold overnight, but I was warned that it wouldn’t. I restarted the fire and burned the rest of the coal. The beginning weight of the coal supplied was 45.5#. The resulting ash was 10# and by volume, about ½. The ash, in every respect, was similar in size and shape to anthracite.
As far as smaller size coal making less smoke well the size does not mean a dam thing on how much it smokes or the btu value of the coal. It will smoke Just the same no matter what size it is . The smoke is produce from the volatiles in the coal not the size of the coal . That Bit ash looks nothing like good Anthracite coal ash not even close. If your Anthracite ash looks like that then you got some pretty bad Anthracite coal Refuse or/ old banked coal. The ash content of that Bit coal comes out to be 21.97% ash content . The size of the coal on left is more like Buckwheat size and pea mix in then Rice size coal . Anthracite Rice should be 5/16" X 3/16" Buckwheat should be 9/16" X 5/16" Pea should be 13/16" X 9/16" I see some one Edit my post Thanks forgot to do it myself .
Last edited by coal berner on Sun Jul 04, 2010 2:49 pm, edited 1 time in total.
nice test-burn stokerman. The three "bad" things noted are mostly from the 50% brookville (ohio 'sulfur vein') coal that I blended w/ the kentucky. unfortunately i didn't have any unblended coal to send. the carbon in the ash, the high ash content, and the light smoke are all from the ohio brookville coal. the kentucky coal burns clean, hot, and with little white fluffy ash; but it's more expensive - about twice the price. coal-burner, as far as soot being a function of the volitiles in the coal, that's somewhat true, but one coal with a high volitile content may burn much, much cleaner than a bituminous with a mid-volitile content, that's actually quite common. i'm not quite sure why there was so much anger towards bituminous coal in that post, but with much bituminous having more heat, less ash, wider geographical availability, and a much lower price than anthracite, these are good experiments to conduct.
Berlin wrote:nice test-burn stokerman. The three "bad" things noted are mostly from the 50% brookville (ohio 'sulfur vein') coal that I blended w/ the kentucky. unfortunately i didn't have any unblended coal to send. the carbon in the ash, the high ash content, and the light smoke are all from the ohio brookville coal. the kentucky coal burns clean, hot, and with little white fluffy ash; but it's more expensive - about twice the price. coal-burner, as far as soot being a function of the volitiles in the coal, that's somewhat true, but one coal with a high volitile content may burn much, much cleaner than a bituminous with a mid-volitile content, that's actually quite common. i'm not quite sure why there was so much anger towards bituminous coal in that post, but with much bituminous having more heat, less ash, wider geographical availability, and a much lower price than anthracite, these are good experiments to conduct.
What anger I am all for opening a bigger coal market for efm or any other company that makes stoker boilers if they can get bit coal to work & work well in these units I say go for it much larger Market when it comes to bit coal for the company and consumer. As far as for more btu's and less ash with some bit coal then with anthracite coal well that goes both ways all depends on the coal / the vein of coal. One thing is true there is no bit coal that I know of that burns cleaner then anthracite coal . Also as far as ash content goes any coal that is under 6% ash content is a waste to burn because it burns up to fast and produces to much flyash. That's why 99 % of the breakers will mix the coal to get the ash
content up so it will burn longer and hotter . At least in the Anthracite industry that's how it works . The standard Anthracite mixing formula that is allowed is 3% slate 4% bone mix in with the coal . You will see that used in the bigger surface mine breakers . In the underground mines you will not see that because the slate is not a factor because the coal vein is exposed but the coal will have the bone in it because it is & was formed in with the coal . Most of it will be removed from the coal at the breaker but not all of it will be .
Stoker-man, does this mean the Ky Bit in rice or Buckwheat WILL burn in an EFM 520 Highboy? That is the message I am getting here. If I send you a sample of Ky Bit buckwheat coal could you see how it would burn? Thanks, Gardnerbuddy
after conducting some tests on this coal, I have discovered a few things. I have used this specific blend of ohio and kentucky coal to heat my own home and others have used it as well. I was surprised at the high ash content based on the EFM experiment and, after intially assuming it was result of the ohio coal, decided to delve further into this question. According to the Mine, the ohio coal should have between 9-13% ash; and the KY coal should be around 8%. Obviously this leaves us with a problem, because based on that, in a worst case scenario I should be looking at around 13% ash (providing no unburned coal, which there always is). I've found this coal blend to be relatively low ash compared to others that i've burned in the same conditions in the same appliance at my home. After looking at the "ash" in the photo, i believe the problem is that there is far too much coke production, and far too much coke and carbon in the ash, I should have paid closer attention the first time i viewed this thread. As stoker-man noted, these particular coals are noticeably harder to crush or break and are quite dense which leads to them requiring more air for thorough combustion. In a clinkering type stoker, this is less of a concern as the excess coke will sit in the firebrick hearth until it has been fully combusted, but in an underfeed stoker not set in a hearth, it will require more air (perhaps less feed?) to combust this fuel before the ash is dumped into the ashpan.
I ran 50lbs of coal through the combustioneer and ended up with just under 6lbs of ash. This is more consistant with what i've been experiencing, also i paid close attention to the volume, it's less than 1/10th the volume, however some of it is clinker - which means that it would be considerably less volume than an appliance that produces a more powdery less fused ash, so not necessarily apples to apples as far as what a EFM may produce.
I believe that an EFM stoker would burn these coals satisfactorily, especially with more experimentation/adjustment and proper sizing, however i think that with this particular blend, expect a higher percentage of unbuned coal in the ash- giving it much more air MAY lead to clinkering in the tuyeres.