# alcohol firing...



## Phippsburg Eric (Jan 10, 2008)

As you have seen I have been playing with a coal/wood pellet fired Ruby. I am trying alcohol fire now.


























I have built a "chicken feed" tank with sump and three burners. after a fair amount of fiddling, I got it to work as intended. It burns without over flowing or going out. It seems to meter fuel correctly even with the regulator valve full open. It makes a flame about 4-6" tall nice and blue with a bit of yellow at the top.








the burner fits up into the firebox with the wicks just below the firebox door and the boiler tubes. the firebox is about 1 3/4" long 1/14 wide and about 2" deep.










I have tried several wick systems using materials at hand. this photo shows stainless mesh wicks. 

I have tried fiberglass yarn teased from heavy fiberglass cloth. All the fibers run up and down. Seems to work well, perhaps even best, but the bundle of fibers is nasty to work with and tends to fall out of the burner. I stuff as many as I can into the burner tube.

I also have tried a piece of braided fiberglass - a gasket for wood stove doors. it is just smaller than the burner tubes. works good, perhaps just a bit less well than the bundle of fibers. also falls out of the burner.

The stainless mesh is wrapped in a loose coil and pushed into the burner body. seems to work as well as the braided fiberglass. it is a little harder to light though. does not fall out of the burner which is a plus!


OK! ... Now, you will notice I do not have any pretty photos of the engine steaming along pulling a hundred loaded cars with its safety popping! I can JUST get steam up to about 10-15 PSI which is Not enough for any useful work, though the blower does go. I can creep around a little of the line near my steamup bay but cannot climb the least grade.









SO, what can I do to get more heat out of the fire?


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## steamlogger (Jan 2, 2008)

Just a thought but your fresh air intake from the bottom might be too much. How about a plate with narrow slots on each side of the burner. 
I have an Argyle SPC #3 4-4-0 that is Alcohol fired and it has a narrow fire box.


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## seadawg (Jan 2, 2008)

Give us a gander at the fire box, would be helpful. I built a whole new boiler (JvR C-type) for my C-16 and use alcohol to heat it up. (4 wicks) I use some kind of woven black plumbers soldering blanket for wick material. It works great and doesn't burn if I run it dry. 

Could also be the wicks might be too close to the underside of the boiler. Does the burning rich smell go away or does it always smell link a toxic chemical plant that burns your eyes?


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## Phippsburg Eric (Jan 10, 2008)

here are a couple of photos of the firebox i took as I built the boiler. It is currently open to the bottom less the area of the metal plate on the burners. I will try some baffles to reduce air intake, perhaps their is too much air which cools the fire?

It does not smell "rich" or burn the eyes when burning. I think it is complete and proper combustion but not enough of it.

One thought I had was a baffle above the flame to make the fire path longer while still in the firebox. It will be hard to do as there is nothing to attach it to though. and I am not sure if it will help much as the gasses coming out the fan are not really hot, so I think the heat that is being created is being absorbed by the boiler.


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## seadawg (Jan 2, 2008)

You may also try what Robb suggests above by adding some restrictions to the air being admitted from below. There has been a fair amount of discussions about how much air is required for alcohol combustion. It might be even more critical for a "locomotive type" boiler such as yours. I've seen some Aster locos (I studied as many as I could gain access to when designing my C-16 firebox.) with VERY small holes for air admission.

From what I have read, alcohol seems to be better at tranferring heat by direct contact with the flame as opposed to hot gasses in flues or radiant heat (of coal). Maybe something like a brick arch (O.K., not a real brick arch, but something that directs the flames backwards towards the door first, then towards the flues. Might be able to mount a piece of brass to the front part of your wick assembly to deflect the flames rear-ward.)


cool pic of a brick arch


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## Steve Shyvers (Jan 2, 2008)

Eric, a coal fire produces radiant heat, lots of it, so the crownsheet, sides, and tube plate in the firebox comprise the most effective heated surfaces in a coal-fired boiler. An alcohol flame does not produce much radiant heat, so Dave's correct that for an alcohol fire the best heat transfer occurs when the flame is in contact with the heated surface. A "brick arch" may be ineffective with alcohol, because the flame will contact it, heat it up, and give up a lot of heat from the combustion gasses that won't go to work to heat up the rest of the boiler. Brick arches function in coal-fired locomotives to lengthen the combustion path so that there is more complete combustion of the gases from the coal and to force the hot combustion gasses back to heat up the "wet" surfaces toward the back of the firebox. 

Your best bet for a next experiment is to do what has been suggested and restrict the air into the bottom of the firebox. The draft of the fire and gasses thru the flues will suck in a lot of cold air through the open bottom of the firebox. I've changed a vertical boiler from an indifferent steamer to a strong steamer just by doing this. 

PS I have used strips of rolled-up fibreglass reinforcing tape as wicks. Works fine but tends to clog up over time, so needs periodic maintenance by poking it multiple times with a large sewing needle to make it porous again. I've also used strips of old cotton t-shirt, but the tips char a bit so the wicks need periodic height readjustment. 

Steve


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## Semper Vaporo (Jan 2, 2008)

You might try putting "turbulators" in the flues... basically this is a thin strip of copper as long as the flue and as wide as the diameter of the flue, but twisted/spiraled maybe 1 turn per inch. The idea is add turbulance to the hot gases in the flues to get the gases in better contact with the flue walls. Home gas waterheaters have this type of device in the flue, up the center of the water tank.


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## David Leech (Dec 9, 2008)

Eric, 
I would suggest trying 'regular' wick material, instead of what you have been using, as a 'known' test, as I am not sure about other types as have personally had no experience with them. 
Either good old asbestos type, or the more modern 'ultimate wick' type stuff. 
The wicks should be just loose enough that you think that they will fall out if you turn it upside down. 
Then see how much heat is coming out of the stack when it is running. 
Just a thought. 
All the best, 
David Leech, Delta, Canada


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## Charles (Jan 2, 2008)

Eric
One of the corrective measures used to improve the alcohol fired Accucraft GS4 was to install a "brick arch." For the GS4 we found the heat was going up the stack: very hot stack gasses. Thereby, putting the arch in diverted the gases and flame allow more energy to be transferred to the heating surfaces. An arch encourages combustion of gas distilled from the firebed; it lengthens the path of those gases to give additional time for combustion and it prevents cool air reaching the fire tubes. One can also put a combustion chamber in the design of the boiler. Not uncommon to have this as "brick arch" utilized for example: Aster Berk, CP Hudson:


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## roadranger (Jan 6, 2008)

Eric - you've said the stack gasses are relatively cool, indicating the boiler is absorbing the heat. So I would think more or larger burners are needed to produce more heat. 
Need to ramp up the BTU's to match the pellet BTU output for that size firebox... fill that firebox with flame.
I would think 3 larger burners would be far easier to work with, maintenance and fabrication wise, than doubling the burners you have now to 6 times.


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## Phippsburg Eric (Jan 10, 2008)

I did two things which both helped the steaming of my engine. I thank you all for the help. I am sure we can think of some things to make it better still.







]

This is the new "ash pan" which limits the air flow. I started with 5/32" holes and opened them up with progressively larger drills to see what happens. these are more like 7/32" and seem to work well. the stack temperature is definitely higher now and I get more boiler pressure.

I also added an arch:










This stainless steel arch Is just bent and clipped to the bottom of front sheet of the firebox. It is bent just below the boiler tubes and reaches to near the top of the fire door. It seems to have gotten good and hot during operation, though I didnt really look in while the fire was burning beyond this photo:










It does look like it is starting to glow red here.










The engine seems much perkier now! It runs strongly in reverse ( it is a Ruby at heart!) 

The feed pump keeps up well with the water use, in fact I probably should install a bypass. Running with wood pellets, it used a bit of water and I didn.t feel the need for a bypass. probably because I used more steam running the blower.
The stack gas now is quite hot which it wasn't before.


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## xo18thfa (Jan 2, 2008)

With the restricted air, run the blower a smidge more to really pull the fire through. As David suggested, use regular, individual wicks. It takes some experimentation to determine how many to use and how to shape the head. Essentially put in just enough so they don't fall out if you tip the engine. Shape the head like a mushroom. That will make the wicks draw and burn more fuel. If it's too much, trim them down.


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## Phippsburg Eric (Jan 10, 2008)

Bob-- 

That is good advice. It runs reasonably on the stainless mesh wicks, I'll try some of the others types too. When you say "regular wicks" could you define that or offer a link to a product?


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## xo18thfa (Jan 2, 2008)

Hi Eric: Actually I use ordinary cotton candle wick. 1/16" diameter. You can probably get it at Micheal's or other art&crafts stores. The downside with cotton wick is they will burn. So you can't let the fuel tank run dry. Upside is they tend to stay cleaner. Fiber glass wick can get a crusty crud build-up sometimes. I've had good success with cotton candle wick.

There is a wick made of woven fiber glass for use in oil candles and oil lamps. I have not tried it, but I bet the 1/16 dia would do the job. Local arts & crafts may have it. These guys carry it in 10 foot spools:

Southern Lamp Supply


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## Phippsburg Eric (Jan 10, 2008)

I ran the engine today. at first it was somewhat disappointing. I checked the timing and adjusted it which helped alot,I also got it running well in the forward direction by reversing the eccentrics.

Next, I cleaned out the remaining residue from the wood pellets. that seemed to do the trick. the alcohol fire and moisture seemed to have softened and swelled the black stuff in the boiler. one tube was just about blocked and the others partially blocked. I used a scraper and flue brush as well as compressed air to scour the flues and smokebox. I didnt do much to the fire box this time as access is limited by the stainless steel "arch" 

I got two and three quarters laps at a good speed with a very wet exhaust. I gotta add a bypass to the feed pump. 

The stainless steel mesh burners seem quite good


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## Taperpin (Jan 6, 2008)

Eric, 
There are some "rules of thumb" for alcohol fired boilers which you might like to consider .. 

[1] The wick tops area [total] should be equal or a little larger than the total flue area ie: 5 off 1/2" diameter flues then the wicks top area should be 
5 off 1/2" diameter. 

[2] The air intake area should be around 3 times the wick top area ,much more than this and too much cold air can lower the combustion temperature. 

[3] Alcohol needs along flame path to promote complete burning..so sometimes a deflector arch can be useful..the flame will take the shortest path to the low pressure area [flue entrance] and do nothing because its not touching firebox surfaces on the way.. 


Gordon.


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## Phippsburg Eric (Jan 10, 2008)

Gordon-- 

I think I am pretty close to those rules of thumb, I am glad you wrote them down. I will check my measurements to see how close I came.


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## kno3 (Aug 25, 2008)

Posted By Phippsburg Eric on 03 Aug 2012 03:27 PM 


"... The engine seems much perkier now! It runs strongly in reverse ( it is a Ruby at heart!)"




Hi,
Could this be because in reverse it the piston valve has inside admission while in forward it has outside admission?

Outside admission puts unecessary steam pressure on the ends of the piston valves and makes the engine run less good.

In this case you could change to inside admission for forward, which shouldn't be a difficult job. it requires only turning the eccentrics relative to the crankshaft. I believe there was a topic around here on how to do that.


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## Phippsburg Eric (Jan 10, 2008)

You are quite right. I reversed the admission by rotating the eccentrics 180 degrees and she runs smoothly forward. while adjusting the valves, i got revers working well as well as smoothed out the running.


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