The Coal Brick Experiment

[Ken Fleming]

Sat. & Sun. sounds like a good time to do the second half of the "Coal Brick" experiment and see how well they burn.  If they work out, then we can do a full scale production run this fall work weekend, if not before.  I would like some feedback.

[Jason M Lamontagne]

I was planning on experimenting with the coal bricks this weekend; I'll certainly report back!

Coal Bricks:

With great enthusiasm, while firing for Bullet Bob on Sunday, I gave the coal bricks an earnest test.  I told the guys there that I intended to fire an entire trip without touching the scoop- and only hucking in coal bricks.  And I did-- the 11 AM trip.  The bricks did not break up on there own at all- and if left to their own devices, would burn slowly and evenly from the outside in.  They get a chalky look when about 1/2 gone.  Subsequent to this, I think the 1 PM trip, I fired "mixed fuel"- that is half bricks and half coal from the bunker.  It should be noted that we got into a good vane of regular coal- apparently from the bottom of our B&ML load, some of their old stuff. 

Our initial conclusions were that they would work alright when laid on a good burning bed and when fired mixed with regular coal.  But then...  We skipped the 2, and for the 3 had a lone passenger whom we loaded into the cab and gave a light engine ride to- leaving the coaches behind.  Oh- and Bob and I switched sides.  (That was, I might add, the key part of this experiment...)  In short-  no air got to the fire, and we had a miserable time making any steam, hauling nothing.  After that, we pulled out enough door-sized clinkers to let some air through to haul the train for the 4PM trip.  When all done- we found the entire grate area sealed with a layer of greenish-tone glassy clinkery something-or-other thoroughly glued to the grate.  We pulled a bunch out- but there's still some glued to the grate(who's firing next?).  We saved a bunch also for everyone to study.  We did burn all of the existing bricks in the experiment.

I believe it's not entirely fair to blame this solely on the coal brick project- I think a small amount of the clinker was due to the cement binder, however it was very similar clinker that we got from that load of coal prior to our screening operations- which would indicate it's whatever that dust is.  Perhaps some actual coal dust would do better- but we will be going to great lengths to avoid buying coal with more dust. 

As I mentioned above- the critical part of firing the bricks is to get someone else to fire just prior to their gluing themselves to the grate- they work just fine up to that point...  Bullet Bob might have a slightly different opinion...

I'd say it was a great effort and idea- thanks to Ken and the others who helped him- but the critical flaw here is what we had to work with.  Let's keep the good ideas rolling...

Jason

[Ken Fleming]

The results of burning the coal bricks is very interesting.  Jason had a concern about the cement forming clinker.  Cement does burn, I am not sure of the temperature (will find out) and cement itself is ground clinker.  The "glass" appearance would seem to indicate some sand present, however the temperature to make glass should burn the cement.  Be sure and save some samples of the clinker and I will try to find a college lab to analyze it.  The ratio of 6 coal, 1 saw dust and 1/4 cement can be changed to 7 coal:1/4 cement for another try.  The dust we used was from near the middle to the top of the pile nearest the car shop and was a clean as that in the pile.  The saw dust (from PA mill) was clean, but did have a high moisture content, but should not cause clinker (who knows the chemistry at elevated temperatures).

Coal dust can be pressed into "briquettes" without a binder.  Perhaps our shop can turn out a test press using some 3" steel pipe, a chunk of plate for a plunger, a frame and hydraulic jack.  Then press a few "Coal Pucks" to test.  There are plenty of YouTube videos on coal brick and biomass presses for ideas.  There are presses out there that will turn coal dust or even Fred's grass clippings or wood chips into usable fuel.

Lets make a contest of this.  I will give a $100 prize to whomever can show up a Sheepscot Station with a practical and productive device that will make our coal dust into a usable and trouble free form for firing a steam locomotive.  This offer will expire on June 1, 2011.  The firemen of #10 will be the judges and should inform me directly as to whom the winner is.  Use the KISS principle!

[Jason M Lamontagne]

Please bear in mind that I don't think the bricks were the problem- I think it was the dust we are working with.  I wouldn't be surprised if that dust turned out to be half gravel.  I don't want to put any more of that particular dust into the firebox- especially with new grates coming.  The clinkers we got Sunday were like the clinkers we got a few years ago from the same dust (except for the greenish hue).

Jason

[Ed Lecuyer]

*Mods Note*
Thread split from May Work Planning topic.

Mike Fox posted this picture:

The coal brick before being burned, and after. The entire grates were covered by the latter, forming one massive clinker. In all fairness, the bricks burned hot, according to Jason, and also performed very well. Aside from the clinker issue. One of them looked like we had made glass, due to sand.

I will give a $100 prize to whomever can show up at Sheepscot Station with a practical and productive device that will make our coal dust into a usable and trouble free form for firing a steam locomotive.

Sounds like "Cash for (no) Clinkers"

[Ken Fleming]

Maybe we can use the coal bricks for heat at Alna Center. I do have help coming.  Penn State is doing a little digging in their files.  They may even do some chemistry tests on clinkers and ash.  We'll see. 

[Ira Schreiber]

A little personal experience.
Back in the late 60's, early 70's, I was firing and engineering a series of 24" gauge Crowns.
We used coal briquettes for fuel.
These looked like charcoal but were actually compressed coal bricks.
Though they burned hot and relatively clean, they were subject to clinkers. If a poor firing technique was used, the grates would plug up and steam could not be maintained. When this happened, usually a large (covering the entire grate area) clinker would be found. These clinkers were very glassy looking, too.
They looked very much like the clinkers pulled from #10.
My theory is that it is the binder used to hold the brick together. If you kept pulling the small clinkers, there was no problem.

[Jonathan St.Mary]

Clinkers are usually formed from the melting and fusing of metals and sulfur when coal is burned at high temperatures.  Coal is commonly contaminated with pyrites (iron sulfide).  The formation of clinkers is generally worse at higher firing temperatures.  As already noted, the bricks fired hot.  While lab analysis may prove otherwise, my suspicion is that the bricks burned hotter than the "raw" coal, thus promoting clinker formation.  When burning bricks, the fire will have to be poked more often, and clinkers removed regularly, to prevent the formation of a massive, grate choking, blob of clinker. 

A similar effect was found when burning rice coal instead of larger lump coal in stoves.  Rice coal presents more surface area per pound than lump coal, and tends to burn hotter and faster as a result.  Sort of like throwing kindling on a fire as opposed to throwing on a 6" log.  The fire took more tending, and the draft had to be adjusted to reduce the fire temperature to about the same level as the lump coal previously used in order to reduce clinker formation.

Jonathan St.Mary

[Henry Stahle]

The development of a device for making coal bricks sounds interesting.  Can you tell me what grade of coal you purchase and why there seems to be so much coal dust?   Is there a place I can purchase some coal dust without having to travel to Sheepscot, Maine.
I do not remember coal dust being a problem during the summers that I worked at Pleasure Island.  However, we used soft, high sulfur coal that came in large lumps.

[John L Dobson]

In the 1950s the French used coal briquettes quite extensively, and successfully, for firing steam Locomotives - especially on secondary duties and on minor (narrow gauge) lines. Does anyone have a 'French Connection' who might find out how they were made?

[Ken Fleming]

I am sure any coal dust would do for the pressing technique.  Maybe someone will mail you some of ours to try.  The dust and fines comes from screening the coal as we receive it.  Some dust in natural and some is from transportation and handling.  I just felt we needed to do something useful with, thus the brick idea.  Ideally, we would turn all of our dust and fines into neat stack of bricks and bust them up just before going into the firebox.  The side benefit is a clean coal pile.  

As clinker goes that's another story.  I think that not breaking up the bricks before firing with them added to the problem.  The quality and type of coal was one variable, the amount and type of binder (Portland cement) and the use of a filler (saw dust), all must be considered.  The ratio of material to binder was 28:1, seems large enough to me.  Then, throw in the temperatures in a locomotives firebox and strange things can happen with the chemistry.  That's why it was an "experiment".  Next, we try a different ratio of coal dust to binder and no more filler.  After that, we'll try same ratio with different binder.  Problem is the binder used must allow us to remove bricks from the molds without falling apart while moving them to a place to dry.  The coal/cement bricks stayed together nicely, except if handled before they were dry.  Penn State has suggested using molasses (non-food grade) as a binder.  Questions become will they set up quickly enough to remove bricks from molds and will they be rain proof?  I found a source of non-food grade molasses this afternoon.  From a gallon all the way up to a tank car load, ready to go.  Will #10 smell like a bakery?

Anyone is welcome to try making coal brick samples. They can molded in an ice cube tray, muffin tin or small loaf pan and using anything for a binder.  A binder that burns is best.  Burn them in your backyard BBQ and see what happens.  Then bring your ideas forward.  Just use the K.I.S.S principle and keep it cheap.

Pressing coal dust into briquettes is another option.  Thus, my offer of a $100 prize for anyone who brings a workable/practable  press to Alna by 6/1/2011.

[Ken Fleming]

There are many coal briquette machines on the market, even on eBay, but their price does not work out for us.  A $3,500 machine would do our dust pile in a day, then what do we do with it?  Not much business in coal briquettes.

I rode on a Swiss rack engine that used pressed coal blocks (about foot square) they work. We just need to get it right or at least near right.

[James Patten]

The coal from which the dust came from was Pocohantas coal.  The coal itself caused lots of clinkers to form, so I'm not too surprised that the dust bricks turned into clinkers themselves.

[Jason M Lamontagne]

I must say again that I'm not real enthused about throwing any more of the current dust, in any form, into our firebox.  We're currently on old, nasty, used-up grates.  Once we have our new grates we should not be doing such experiments- and risk overheating brandy new ones.  The grates were indeed glowing at Sunday's end.

[Ken Fleming]

Consider the subject closed!