what is our efficiency?

what is our efficiency?

PostBy: staybolt On: Fri Jan 13, 2012 8:42 am

Has anyone done a combustion test on their boiler to determine burner efficiency, ie CO2/O2 to determine combustion %? I know with flyash and a little soot can reduce thermal efficiency in heat exchanger. We don't condense water on our flues so we cannot get into the mid 80% range. Just wondering... tnx Guy
staybolt
 
Stove/Furnace Make: keystoker boiler, godin stove
Stove/Furnace Model: kaa-2, "grand"

Re: what is our efficiency?

PostBy: WNY On: Fri Jan 13, 2012 9:11 am

It been talked about, but not sure if anyone has done it. If you SEARCH on Efficiency....There are also other threads about Efficiency too.

Measuring Combustion Efficiency
WNY
 
Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker, LL & CoalTrol
Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon

Re: what is our efficiency?

PostBy: Rob R. On: Fri Jan 13, 2012 9:25 am

A friend of mine had his EFM checked. I seem to have lost the email with the individual values, but I remember that the final efficiency number was 81%. That was with a squeaky clean boiler & stoker.

staybolt wrote:I know with flyash and a little soot can reduce thermal efficiency in heat exchanger.


Keep the heat exchanger brushed out, and use the minimum amount of air necessary to burn the coal. Do not adjust the air purely on the appearance of the ashes, if you try and burn all trace amounts of coal out of the ash you are sending a greater amount of btu's up the chimney.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Other Heating: Dad's 1953 EFM Highboy

Visit Lehigh Anthracite

Re: what is our efficiency?

PostBy: coaledsweat On: Fri Jan 13, 2012 9:57 am

The AAs and AHSs have an advantage due to their design, they can run over 85%.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: what is our efficiency?

PostBy: coalkirk On: Fri Jan 13, 2012 9:24 pm

It would be interesting to know. But the only stat I really care about is it costs me 1/3 the cost of oil and my home is warm. :D ;)
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal

Re: what is our efficiency?

PostBy: VigIIPeaBurner On: Fri Jan 13, 2012 10:21 pm

staybolt wrote:...8<.. We don't condense water on our flues so we cannot get into the mid 80% range. Just wondering... tnx Guy


The main combustion product of coal is CO2 and CO; carbon dioxide and carbon monoxide respectively (C+O2=CO or CO2). Since coal is mostly all carbon, the level of hydrocarbons (CH) in coal is low. The water vapor content of the combustion exhaust is low (CH+O2= CO2+H2O). You shouldn't see water condnsing and coming out of your chimney if burning anthracite, just heat waves :)
VigIIPeaBurner
 
Hot Air Coal Stoker Furnace: Keystoker Koker
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Re: what is our efficiency?

PostBy: Yanche On: Fri Jan 13, 2012 11:58 pm

I own instruments to measure CO2, CO, O2, draft and temperature in the flue gas. This would allow me to calculate combustion efficiency. But other than draft I haven't measured a thing. There's nothing very adjustable on my boiler. And as "coalkirk" says all that really matters is how much I'm saving over oil. The savings are so great I don't really care about the numbers.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: what is our efficiency?

PostBy: staybolt On: Sat Jan 14, 2012 8:09 am

What is the blue flame caused by? Isn't that coal gas made of some hydro carbon? Burn the gasses out of it then you get glowing gravel then the ash coating starts. Just thinking of how to make my Kaa2 more efficient that's all. Tnx Guy
staybolt
 
Stove/Furnace Make: keystoker boiler, godin stove
Stove/Furnace Model: kaa-2, "grand"

Re: what is our efficiency?

PostBy: Rob R. On: Sat Jan 14, 2012 8:13 am

staybolt wrote:Just thinking of how to make my Kaa2 more efficient that's all.


Keep it clean and don't run it any hotter than necessary to heat your house.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Other Heating: Dad's 1953 EFM Highboy

Re: what is our efficiency?

PostBy: VigIIPeaBurner On: Sat Jan 14, 2012 1:03 pm

staybolt wrote:What is the blue flame caused by? Isn't that coal gas made of some hydro carbon? Burn the gasses out of it then you get glowing gravel then the ash coating starts. Just thinking of how to make my Kaa2 more efficient that's all. Tnx Guy


Yup, that's mostly methane - coal gas. There isn't that much compared to the total carbon content and the gasses tend to be smaller chain molecules. Methane (nat gas), Propane and fuel oil are all hydrocarbon (gaseous and liquids) so there's a fair amount of water released as a combustion product.
VigIIPeaBurner
 
Hot Air Coal Stoker Furnace: Keystoker Koker
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Re: what is our efficiency?

PostBy: Yanche On: Sat Jan 14, 2012 5:00 pm

The term efficiency is an often misused and misunderstood. What is being discussed here is combustion efficiency. How well the fuel is burned, compared to it's theoretical maximum. This has nothing to do with overall efficiency, the efficiency of the appliance burning the fuel. For example I could burn fuel at theoretical efficiency in a fireplace and it wouldn't heat my house very well.

All fuels consist mostly of atomic Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Sulfur (S), minerals (ash) and water (H2O). In fuel combustion the molecular Oxygen (O2) in air react with the combustible components of a fuel. As an example the fuel Carbon (C) reacts with O2 of the air to generate Carbon Dioxide (CO2). If the reaction is incomplete Carbon Monoxide (CO) is produced. The empirically determined formula for Anthracite coal is:

Anthracite_Formula.jpg
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Perfect combustion is simply a mixture of fuel and oxygen, with both being completely consumed in the burning process. The ideal situation would be to provide just enough air in the combustion chamber to insure complete burning of the fuel. This would be true if it were physically possible to bring each atom of fuel in direct contact with the amount of air required to complete its combustion.

If we reduce the amount of oxygen, in a perfect mixture, we would have a fuel-rich condition. However, if we increase the amount of oxygen, in a perfect mixture, we now have excess, which does not contribute to the burning process. Having just the right amount of oxygen (no more, no less) is called the stoichiometric point, or stoichiometric combustion. The stoichiometric point is also called the 100% air point.
Anything above the 100% point is called excess. Excess air just goes out the chimney lower the amount of heat that heats your home.

The excess air is above theoretical is typically, 1.3-1.5 times for mechanical (stoker) firing and 1.5-2.5 times for hand firing.

Use the above Anthracite formula in combination with your amount of excess air to determine where you are operating you coal appliance. :-)
Get out your high school chemistry books and just do it.

If you are up to it, here's the formula you need. Just match up the x's and y's of coal.

Combustion_in_air.jpg
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In all seriousness it would only be an academic exercise, because you couldn't possible expect your coal, a mineral, to be consistent load to load and the amount of air supplied would vary with the weather. What you can do is understand what changes how much heat goes up your chimney is dependent on excess air amount. This is the only thing you can control. The other is how well your coal appliance extracts the heat out of coal combustion and puts it into your home. This is designed into you coal appliance, and there is nothing you can do about it. That's why it's important to buy the right coal appliance and why for efficiency reasons you don't use your fireplace.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: what is our efficiency?

PostBy: LsFarm On: Sat Jan 14, 2012 5:26 pm

Yanche wrote:I own instruments to measure CO2, CO, O2, draft and temperature in the flue gas. This would allow me to calculate combustion efficiency. But other than draft I haven't measured a thing. There's nothing very adjustable on my boiler. And as "coalkirk" says all that really matters is how much I'm saving over oil. The savings are so great I don't really care about the numbers.



Yanche, I was really worried about you when I read this post.. who kidnapped Yanche?? and what have you done with him? Who's impersonating him on the
forum??

But now I see a much more 'Yanche-like' post, with all the pertinent mathmatical formulas and explainations..

My faith in you is restored.. :)

Just teasing you..

Take care,
Greg L
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

Re: what is our efficiency?

PostBy: Berlin On: Sat Jan 14, 2012 5:52 pm

staybolt wrote:What is the blue flame caused by? Isn't that coal gas made of some hydro carbon? Burn the gasses out of it then you get glowing gravel then the ash coating starts. Just thinking of how to make my Kaa2 more efficient that's all. Tnx Guy


The blue flame is mostly carbon monoxide burning along with a very very small amount of hydrocarbons.
Berlin
 
Hot Air Coal Stoker Furnace: Will-Burt Combustioneer 77B
Coal Size/Type: Ohio BITUMINOUS pea stoker coal

Re: what is our efficiency?

PostBy: VigIIPeaBurner On: Sat Jan 14, 2012 6:44 pm

Berlin wrote:
staybolt wrote:What is the blue flame caused by? Isn't that coal gas made of some hydro carbon? Burn the gasses out of it then you get glowing gravel then the ash coating starts. Just thinking of how to make my Kaa2 more efficient that's all. Tnx Guy


The blue flame is mostly carbon monoxide burning along with a very very small amount of hydrocarbons.


... CO on it's way to CO2.
Methane:
    CH4+2(02)= (H2CO + H2O)+O2= CO2 + 2(H2O)
Carbon:
    C+O2= CO+O = CO2

Edit: didn't mean to post but did in rush. finished later.
VigIIPeaBurner
 
Hot Air Coal Stoker Furnace: Keystoker Koker
Hand Fed Coal Stove: Vermont Casting Vigilant II 2310
Other Heating: #2 Oil Furnace

Re: what is our efficiency?

PostBy: Berlin On: Sun Jan 15, 2012 2:11 am

Vigpeaburner, I'm not clear on what you're trying to say; The blue flames from anthracite coal are almost entirely from CO, not methane.
Berlin
 
Hot Air Coal Stoker Furnace: Will-Burt Combustioneer 77B
Coal Size/Type: Ohio BITUMINOUS pea stoker coal

Visit Lehigh Anthracite