EFM = Electric Fireman (new project alert)

I make more work for myself because I can't leave well enough alone!

I hear you there.

europachris wrote:

Berlin wrote:with that much soot buildup after 500lbs you need more air. There is also some coke in that clinker, more than you might think; to solve this you need more heat reflection on the fuelbed- this will also prevent soot buildup in the boiler. The key with a clinkering type stoker is to reflect as much heat into the fuelbed as you can - the more heat reflection the less air you'll need to achieve a reduction in coke and soot production and you'll get significantly more dense clinkers. This is why, although you did a great job with your setup, I was encouraging you to extend the base by another 10" or so and add some ceramic fiberboard.

You are absolutely correct, Dr. Berlin! With the added air from yesterday, the soot production turned into fly ash, and it did reduce the amount of coke and improved the clinker density. I am still looking for a source of ceramic board material that won't bankrupt me so I can hang a 12~14" diameter piece over the fire pot and possibly add a strip around the boiler above the firebrick.

I am also evaluating my options for extending the base height, partly due to your comments and experience, and also Coal Berner stating that the cleanout door should be larger. Another 6 to 8 inches on the base height along with moving the door up 4" or 5" and giving the other few inches to the door height would help. Mostly the door is to low once the fire bed has built up. If I was a hot-shot welder/fabricator I'd try to convert the round door to the square door style boiler (or just start looking for a square door boiler top - assuming it will fit my current base sized for the 350). Either way the boiler has to come off the base.....

My original intent was to keep the base as short as possible and keep the firepot as close to the bottom of the boiler as possible so the heat went into the boiler and not into the surrounding base (and into the garage). However, with the current base dimensions, I have enough room to fit a layer of ceramic blanket behind the firebrick.

Well if you want to stick with a efm boiler top with a Sq door You will have to go with a 520 boiler They never made 350
with SQ door . if you go with a 520 top your base will have to grow 2.5" more wide and 3.5" longer that is how much bigger the 520 is to the 350 . Not much but your base will not work back to the drawing board
Also you want to keep them heat exchanger flat plates cleaned out of fly ash or you will have draft problems

Chris, how are things going in the Cold white North West

Things are chuggin' right along, MoBe. House is warm, garage is warm, life is good. I've burned about 1000# in 10 days with some of the coldest weather of the winter.

Last night I "cast" a heat reflector for the firebox using some of the grey high temp fire cement, pearlite and water (cheap DIY recipie for castable refractory). It's 12x12 and 3/4" thick with a 1/2" mesh wire reinforcement layer. Once it dries I'll spackle both sides with some of the tan fireclay cement to seal it and give it a smooth surface and then hang it over the pot and see if I can burn up the coke a little faster.

This coal from the Murphysboro seam is largely mined-out except for some isolated pockets, but being low sulfur and low ash, it was widely used for blending with Eastern coals for metalurgical coke production. Indeed, out of 1000# of coal, I've barely filled a 20 gal. galvanized trash can with ash/clinker.

"Indeed, out of 1000# of coal, I've barely filled a 20 gal. galvanized trash can with ash/clinker"

That's a good sign, that means you don't have excessive amounts of coke mixed with the ash. Burning slightly higher ash coal than you, I will go through a standard outdoor type metal trashcan full of clinkers for about every one ton of coal.

I am still amazed about the low amount of clinker. It must be that around here, we don't know any better, and just burn what the coal sellers offer.

A buddy of mine tends a big stoker fed boiler at a commercial building that goes through 50-60 tons a year. He has already carted off fourty five 55 gallon barrels of clinker this season.

Dave

Chris, Berlin, what is the reported ash quantity of the coal you are burning??

Sounds like very low, like 2-5% ?

Greg L

my blend is probably from 6-10%, I think it was around 6% last time I bothered to weight it. The volume of clinker may not be the same between coals of similar ash % by weight, the coal I'm burning produces mostly iron and metal clinker which is very small but very dense, some coals may have more shale and when I tried anthracite in my furnace, it clinkered fine, but with a larger, lighter clinker with lots of shale and chalk in it. Having the stoker feed and air setting properly matched is a big part of getting nice, dense clinkers. Reducing the coke in my clinker reduced clinker volume considerably and this was accomplished by burning lower coke button coals as well as adding lots of heat reflection to the firebox. After the EFM test with my coal, I realized that unburned coke was wasting much fuel and that the heat reflection in my firebox, placed there to decrease soot production, also eliminated any trace of unburned coal in the clinker. The last load of Ohio blend was less ash, but after adding a substantially larger heat reflecting disc, I have managed to reduce the % of ash by weight to the low end of what my blend should be giving me, which means that heat reflection is VERY important in not wasting coal. Not shoveling loose ash but only removing clinker allows a better fire with lower volume of ash as well.

Seems to me burning Bit is more of an art then burning Anthracite. I find this very interesting.

LsFarm wrote:Chris, Berlin, what is the reported ash quantity of the coal you are burning??

Sounds like very low, like 2-5% ?

Greg L

The coal I am burning is around 5.5% ash. I get a little bit of the really hard, glass-like clinker, but most of it is a looser, "anthracite" style clinker. However, the only coke I get in my clinker bucket is what falls out with the clinker through the door.

I'm still waiting on my DIY reflector to dry enough to where I can handle it. I have a feeling it's not going to be very structurally sound , but we'll see. My goal is to try and burn up the coke as fast (or faster) than it can be produced. Some of it is due to lack of heat reflection, but some is the nature of the coal I'm burning.

I wonder what percentage of potential BTUs are in the coke carried over in the ash? The coke is almost weightless, but pure carbon, so like natural lump charcoal, it has little density but still a lot of heat potential. I can't imagine my coal burning well in a rotating grate stoker without a lot of lost coke unless it was sized similar to buckwheat anthracite. The Prill pot design has no air holes in the "pot" portion where the coal feeds up from the auger (that I can see). The air comes up only through the rotating "grate" area of the ring, which should assist in keeping the coal from sticking together and coking as it does in the clinkering style design like the Iron Fireman.

Remember those fireworks "snakes"??? That's what my coke "tree" reminds me of. The coal burns around the periphery of the pot, but then the log of coke sorta extrudes out from the middle of it.

Hi Chris, did you find time to install the DIY reflector in the boiler yet??

GL

I was wandering the same thing, although unless you have a magic shoe horn that boiler is going to need hoisted from that base.
Do you have any pictures of your creation Chris? I think refractory is a great idea and im anxious to see what you have come up with!

I did install the reflector today, but it's been in the low 30's all day and with some baking and cooking going on there hasn't been much if any call for heat so far.

I didn't take a picture of it (it was really hideous looking), but basically I "cast" a 12"x12" tile, about 3/4" thick with some 1/2" wire mesh in the middle of it. I used a DIY refractory recipe that frankly sucks. I'll be lucky if it stays together.

I cut the corners off to make it somewhat of an octagon, and hung it just above the top of the round door. It fit through the cleanout door by angling it corner to corner. I didn't go through a lot of effort with how it's hanging until I see if it holds up.

I did have a thought (first time for everything.... ) - what about a cast iron skillet lid? I'm pretty sure I can get one in 10" or 12" size. It will last far longer than steel will and maybe work as well as rigid ceramic (and be a lot cheaper) or trying to cast something even out of the proper castable refractory material.

Chris, I know that the National Radiator Company utilized ears on the inside of the intermediate sections to support a cast iron plate when a boiler was sold for the purpose of being fired with a stoker. Off hand I dont know the dimension between the ears but if my memory serves me correct the plate couldn't be more than about 1/2" to 3/8" thick. Nor do I know how long these plates would have lasted because I have never actually seen one installed. When an old timer told me what the ears were for in the sections I first assumed the plate was to protect the intermediates just above the fire pot. However, now im thinking there was more to the design than just protection. So I think a cast iron plate may work well.

OK Chris,, time for another update !!

How is the reflector working, how well is it holding together?

How much snow did you get up north of Chicago??

Greg L