Why is/was the short auger used for burning pellets?

Just my opinion - but burning coal really doesn't get any easier than a clean supply of rice or buck size anthracite being fed into an EFM stoker. Sending prune pits or waste oil up the auger is like trying to use up some old kerosene in the tank of your Rolls Royce by mixing it with gasoline.

Once you have suffered through the waste oiled coal, shut the boiler & stoker down for a good cleaning, and source a supply of clean rice (or buck). Sell the prune pits to someone with a pellet unit, and save the waste oil for a waste oil furnace.

I can see your point Rob and I can assure you that I will not be putting any more waste oil on my rice coal. As for the prune pits though, as soon as this oiled coal is used up they are being blended back in to see if I can get them to work.

Thanks again,
Glenn

I ended up with a similar buildup from wet coal last year. Don't know how that is possible, but there was a solid ledge of fines built up in the same area. Had to chip it out. The coal is dry this year, so I do not expect to see that build up again.

Hummm.... That is what I had planned on doing after this round of coal was gone. I was going to wet it right before I brought it in the basement. I guess I will just build a frame work and cover it with plastic so that when I push in the coal the dust will be vented out side and wont roll through my basement and over my shiny boiler. On kind of an update I had mixed 25% prune pits and dry coal and fed it into Mom and Dad's 520 Higboy about two weeks ago. There coal is in an out side bin and is dry and not oiled. I shut it down and cleaned out the pot. Looked like new with out any buildup what so ever. I am very much looking forward to using up this coal.

Thanks again,
Glenn

I can't see how wet/damp coal fines could cause a crust on the plates. ???Maybe a poor grade of coal???

stoker-man wrote:I can't see how wet/damp coal fines could cause a crust on the plates. ???Maybe a poor grade of coal???

I can see how waste oil could coke up and cause a crust, but In all the years I've used it in my underfeed stoker, I've never had any buildup on the tuyeres until I played with some wood pellets (creosote crust in the bottom of the pot and clogged some of the air holes in the tuyeres, but my air was misadjusted for pellets, which didn't help). I only switched to TSC mineral oil because it's cleaner to handle and being lighter, migrates through the coal much better. Perhaps the air setting is really out of whack and causing burn-back into the screw? I really have no idea.

I've burned some wet coal and never had an issue with that causing any crust either - and this is with bituminous, a coal that as it burns releases tar and cokes and has a high hydrocarbon content compared to anthracite.

I was burning bagged Blaschak last year. It was sopping wet, and certainly did not dry out in the plastic feed barrel. Using Harmony this year, and am much happier with it. A lot less ash, and a lot more heat it seems. All at a cheaper price too

I have seen this buildup in underfed stokers but it took many tons of oiled coal and years to equal the same amount of buildup you had. How were you applying the oil? If you were pouring it on top, I'm thinking it could have been too concentrated in certain areas throughout the coal and was causing the problem.

Oh you are probably right. I just dumped it on with a watering can over the whole pile. It was heavy waste motor oil and it was cold out side so I am sure it took forever for it to go down through the pile.

Thanks,
Glenn

Another thought. The air holes in the grates in your stoker extend lower in the fire pot than in underfeed stokers designed for bituminous coal and could be making the problem worse in this case.

stoker-man wrote:I can't see how wet/damp coal fines could cause a crust on the plates. ???Maybe a poor grade of coal???

I had build up of crust on the opposite side on the plates from the auger inlet. I believe this contributed to the uneven coal burn. Wet coal is bad for the EFM.