Yet another "Incomplete Combustion" Svea 123R thread

Discussion in 'Stove Forum' started by ake, Oct 20, 2021.

  1. ake

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    Hello, Sirs!

    First, apologies if not opening this thread in the proper section.

    As described in the title, my Svea 123R has this common issue: blue flames with some yellow tips. The stove is new, although I already burned almost 1/2L of Primus PowerFuel (the only dedicated fuel for camping stoves available in my country). The output is fine since it can boil 1L of water in 8 minutes in a pot with lid, with a satisfying roaring. Also, it do not has issues like pulsing, big yellow flames on starting or obvious sooting. The pressure test (frozen empty-ish stove dipped in hot water) was also fine, so I imagine the seals and wick are in proper condition. The cleaning needle is also properly set at 4 clicks and no issues with candleing. The thermal transfer between burner and stove is fine since only the burner plate is glowing red and the bell became red-to-black from top to bottom.

    The only thing remaining is the jet nipple. Well, although the stove is new, I tried the nipple from the repair kit, but there was no difference. I also raised the cleaning needle just a little bit when functioning, like trying to simulate a smaller diameter jet, but the yellow tips are still there (smaller, probably proportional with the output).

    Is there anything I miss or I can do to have those hot blue flame on my stove? Well, I could live with what I have, but I wouldn't be a proper "stovie", right?

    And some images:

    1. When fully operating (there are other pictures with bigger or smaller yellow tips, but this one seems to be the average)
    fully_operating.jpeg

    2. Restarted, 1 minute or so after closing down:
    after_restart_1.jpeg

    3. Becoming hot again:
    after_restart_2.jpeg after_restart_3.jpeg

    You can see that the flames after restart are quite nice, but I have a feeling that the purple color on the first and last pictures appear because the red glowing burn plate is reflecting somehow in the blue flame (I could be totally wrong).
    Also, the flame in the second photo (when the burner and plate were less hot) are clean (blue with no yellow tips). But then, the yellow tips issue reappears.

    Thank you for your help and patience!
     
  2. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @ake Nothing wrong or unusual about the flame and from what you describe (no pulsing or start-up issues) your stove is working as it should.

    A red-hot burner plate or burner bell does ‘colour’ the flame.
     
  3. itchy

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    Agreed. Sounds like a hot metal effect. Must be something about the brass used in the bell or burner plate, perhaps traces of sodium or such, but nothing to worry about. You have certainly been thorough -- good work and nice first post.

    Hope you can find something other than PowerFuel to burn, that is a good but expensive way to use the stove.
     
  4. ake

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    Thank you for your kind replies and encouragements! I am just silently craving for those sexy (read "hot") blue flames from this thread and for more clean air
     
  5. ake

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    Update:
    Today, after turning off the stove, I reignite it as described in the first post, just for enjoying that perfect blue flame. Except this time, after reignition I didn't let it to become hot again. Instead, I turned off the valve after just a few seconds. For my surprise, the flame wasn't extinguished and it definitely was more than candleing!
    My guess is that after the first turn-off, the very hot burner transmitted its heat to the stove which, in the absence of cooling by vapourisation built an extra pressure. If true, could that overpressure be related with the complete combustion of the second attempt? I'm trying to understand the physics of this phenomenon.

    Thanks again!
    Florinake
     
  6. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    But it did extinguish? … after some delay. I don’t think ‘extra pressure’ would arise, Florinake, but a small amount of liquid fuel in the valve was unable to vapourise due to the premature shut-down.

    John
     
  7. ake

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    No, not really. After few second, because that sooty flame didn't fade, I blow it off. Well, maybe with enough delay it would go out, but since the test was made indoor, I preferred to avoid that kind of soot, fumes and smell.
     
  8. Yun124

    Yun124 Subscriber

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    IMO The yellow flame is just from the Grate pins.
    The burner would work perfectly.
     
  9. ake

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    Unfortunately, not quite. Here's another picture:
    YellowTips.jpeg
    You can see that the "south" and "west" flames have yellow tips without being in touch with the grate pins.

    Anyway, my problem right now is that I have an idea, and this is hardly a positive thing:
    I'm thinking that incomplete combustion could appear, all other parameters being constant, if the caloritical density (CD) of the fuel is too high (please correct me if I'm wrong). Since the only trusty fuel available is Primus PowerFuel, I'm thinking: what if I drop its CD a little bit without dropping its boiling point or the stove pressure?
    I imagine myself mixing PowerFuel with maximum 10% methanol. In this case, the CD will drop to 94-95% since methanol have much less Carbon in composition, and maybe, just maybe, the combustion will be less incomplete.
    But since it is not recommended to burn alcohol in a white gas stove, yet don't know exactly why, it's smart to ask you: what, in fact, will happen? I want to know that, in order to decide if maximum 10% of methanol will be a dumb thing. Let me start: alcohol is bad for rubber seals (cap and maybe SRV), although 10% would not harm them, Even the auto fuel has 10% alcohol.

    Thank you!
    Florinake
     
  10. Fettler United States

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    Wanna know what I think, you need to get out there and take a hike, in the beauty of Nature, find a cozy spot for a noon day break, brew up some coffee or tea and for sure not to worry about "caloritical density", that's what I think! :)
     
  11. Tony Press

    Tony Press Australia Subscriber

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    The flame looks fine to me, as @presscall said earlier.


    I’ve restored many of these types of burners, and the flame will perform differently, but within good tolerance, depending on many factors. The “perfect” blue flame is sometimes achieved in fettle; sometimes after burning a few tanks; sometime just by putting a pot on; and sometimes by the use of colour filters in photo editors.

    My test is, if the flame does not leave soot that can be wiped off with your finger on the bottom of your pot, you’re fine.

    Cheers

    Tony

    Edit: I’ve used ethanol mixed into naphtha to reduce “flaming outside the mantle” in lanterns, while I’ve been testing them.

    I don’t think your stove needs it though.
     
    Last edited: Oct 21, 2021
  12. Yun124

    Yun124 Subscriber

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    I vote this !
     
  13. ake

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    Thanks!

    My concern is not really about the flame color, but, as in the topic title, about the combustion, because, although there are no washable soot deposits built on the pot, there are smelly fumes, and undoubtedly some non-smelly ones, like CO. And I cannot live with that (pun intended)
     
  14. itchy

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    As long as you can do it safely, you should feel free to experiment with your stove. Chances are it will do no damage and even if it does, it most likely can be repaired. Have fun.

    Priming and shut down will likely result in some odor. Another reason that the best way to use these stoves is outside on a nice day, or even a not so nice day.
     
  15. ake

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    The stove is intended for outdoor use, I just want to know what to expect for it. Maybe in a some winter day I will be forced to use it in a shelter (not tent).

    However, today I learned something new. Just before testing it with fuel+alcohol mix I had an "what if" moment, so I added in the desired proportions these two substances in a small syringe. Since I'm not a chemist I was convinced that alcohol will mix with whatever Primus PowerFuel contains. Except, not. They stayed separated no matter how much I shaked that syringe. So my bold test was ended before it started.

    “It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.”
    Mark Twain
     
  16. itchy

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    Very wise of you to do the test.

    PowerFuel should be almost pure heptane. Turns out, as you discovered, methanol is only slightly soluble in heptane (it is listed as immiscible) -- but, according to this solvent miscibility table, ethanol would have been ok.

    https://www.erowid.org/archive/rhodium/pdf/solvent.miscibility.pdf
     
  17. ake

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    Wow, this table is priceless! If it's not already sticky as a resource somewhere, maybe it should be.

    Thanks, @itchy