Buzzkill Posted November 25, 2015 Share Posted November 25, 2015 Mikey, Could you elaborate a bit? My chemistry is a little rusty, but to the best of my recollection, *any* hydrocarbon fuel will produce water vapor and CO2 as the two main exhaust gases. Doesn't matter if it's wood, coal, gasoline, propane, methane, etc. In fact that's why you can see water dripping from tailpipes on cold days before the entire exhaust system heats up. The water vapor is already hot when it's formed. If it condenses it gives off heat (that's why you can use pressurized steam to reach temperatures over 400 degrees F if you remove the condensate before equilibrium is reached). So, I'm confused as to why the water vapor from burning methane would affect flame or forge temperature more than another hydrocarbon fuel such as propane. Methane (CH4) should give off 2 water molecules and one CO2 molecule when combined with two diatomic molecules of oxygen. Propane (C3H8) would give off 4 water molecules and 3 CO2 molecules when combining with 5 molecules of diatomic oxygen. Granted, the heat given off by the oxidation of the two fuels isn't identical per molecule, but I don't get why there should be such a significant difference between the two pressurized gases in NA burners as long as the design allowed for proper fuel to air ratio and proper mixing in the burner tube. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted November 25, 2015 Share Posted November 25, 2015 Natural gas CH4 propane C3H8 so to get the same amount of C through the fire you have H12 so half again as much to form H2O Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted November 25, 2015 Share Posted November 25, 2015 Right, but both the CO2 and H2O reactions are exothermic, so heat is added in both cases. Methane has only slightly less theoretical heat than propane in complete combustion. What I'm curious about is why methane in a NA burner would end up with significantly less heat than propane if both were run at reasonably high pressures. Since methane requires less oxygen it would seem that the orifice size of the jet/mig tip would be larger than the corresponding propane setup and get a good mix of fuel and air. How does this result in more heat blowing out of the forge than happens with propane? I'm still not seeing why the water vapor would be more of an issue with methane than propane either. I'm not disputing that it is correct; I just don't understand *why* it is correct. Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 26, 2015 Share Posted November 26, 2015 Mike our research into vortices is showing seriously different things. A vortex in a tube is gas flowing over a curved surface and reduces pressure. Reduced pressure in an inducer increases induction. Being a vortex it's linear velocity is much reduced at the outlet so the flame (provided we're using the inducer as a burner) spreads in a broad cone the effect is often mistaken as a "flame holder". Pumping the furnace guys one discovers commercial furnace burners use a strong vortex to prevent direct flame contact with the furnace liner. Some weird chemistry happens to the refractory and really shortens it's life. Mixing improves simply because the air fuel remains in close contact before ignition much longer. Also being a lower pressure propane behaves much more obligingly and mixes easier. I'd need a drawing or two to get a handle on what you're describing with an impeller fan to induce a vortex. I find vortices just too easy to induce to introduce another level of complexity. Heck, if I wanted a blower in the mix I'd introduce the propane into the impeller and forget about mixing issues. Reducing the linear velocity at the furnace is just a matter of tapering the tube. The more volume the mix has to fill the slower it has to go. However, a little experimenting with vortices showed me the over all volume I could introduce into the furnace was significantly less so I let my imagination wander elsewhere. A little electric power and I'm looking at vein shear cavitation to induce thorough, REALLY thorough mixing in a very short space and time. I'd reply to your second post but the software combines them automatically and I'm long winded enough. I'll touch on those thoughts a little later. Oh so many helpful things can be done with furnaces it doesn't make a lot of difference what kind of burners power them. Hmmmm? Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Charlotte Posted November 26, 2015 Share Posted November 26, 2015 16 hours ago, Buzzkill said: Right, but both the CO2 and H2O reactions are exothermic, so heat is added in both cases. Methane has only slightly less theoretical heat than propane in complete combustion. What I'm curious about is why methane in a NA burner would end up with significantly less heat than propane if both were run at reasonably high pressures. Since methane requires less oxygen it would seem that the orifice size of the jet/mig tip would be larger than the corresponding propane setup and get a good mix of fuel and air. How does this result in more heat blowing out of the forge than happens with propane? I'm still not seeing why the water vapor would be more of an issue with methane than propane either. I'm not disputing that it is correct; I just don't understand *why* it is correct. The extra heat comes from the carbon / carbon bonds . It takes heat to break bonds between atoms. Compare propane to propylene and methyactylene / propadiene. and acetylene. The amount of heat is dependent on the net reaction. acetylene is a high energy bond that tales little to break and produces a lot of heat. In fact if you are careless with it acetylene will self polymerize and produce enormous amounts of heat. Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 26, 2015 Share Posted November 26, 2015 3 hours ago, Charlotte said: The extra heat comes from the carbon / carbon bonds . It takes heat to break bonds between atoms. Compare propane to propylene and methyactylene / propadiene. and acetylene. The amount of heat is dependent on the net reaction. acetylene is a high energy bond that tales little to break and produces a lot of heat. In fact if you are careless with it acetylene will self polymerize and produce enormous amounts of heat. I love it when you talk like this Charlotte! I get all goose bumpy! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
arkie Posted November 27, 2015 Share Posted November 27, 2015 4 hours ago, Frosty said: I love it when you talk like this Charlotte! I get all goose bumpy! Frosty The Lucky. Frosty, remember....this IS a family site.... (Happy Thanksgiving!) Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 27, 2015 Share Posted November 27, 2015 1 hour ago, arkie said: Frosty, remember....this IS a family site.... (Happy Thanksgiving!) I'm trying, really I am! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 29, 2015 Share Posted November 29, 2015 Charlotte, Methane's theoretical flame temperature is nearly the same as propane; not its proven heating value, which is about one-half. Both the CO and H2 combustion are heat producing, so minor heat is added in the secondary flame. Formation of the H2O leaches heat from the secondary flame; it does not produce heat. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 29, 2015 Share Posted November 29, 2015 Frosty, I think we're talking apples and oranges. For one thing you seem to be thinking along the lines of vortical flow in an expanding tapered mixing tube, which will produce some effects that I'm speaking of, but will reverse others. I'm recommending producing spin (not push) at the large opening of a funnel; that funnel's small opening connects to the rear end of a burner's mixing tube. One facet of vortical flow (speeding forward motion of the mix my way, and slowing it your way) are opposite effects of the same principle used in reverse; same principle but different applications. Better mixing and and lowered flame nozzle pressure will happen both ways. I don't find one method superior to the other; I see both of them proving useful, so long as they are applied deliberately. Mikey Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted November 29, 2015 Share Posted November 29, 2015 Buzzkill, I just wrote you a lengthy reply, which promptly disappeared into cyberspace when I pressed "Submit Reply." So this one will be short. Methane is rated about one-half as effective at heating as other fuel gases. Water formation in the secondary flame is the reason given for this inconvenient fact. I've used methane heating torches, which put out really impressive looking flames, and can tell you from first hand experience that the poor heating performance quoted is so. This information is all available on the web. Mikey Quote Link to comment Share on other sites More sharing options...
ianinsa Posted November 29, 2015 Share Posted November 29, 2015 This is a very interesting debate and makes for a good read! I have been playing around with my Umo burners introducing LPG at different places and adding 'turbulence impellers ' etc. One thing I have found though is when adding the gas to the Intake of the blower you can get a serious "big dog effect" ie. Attention getting, trouser whetting "Woof' just when you don't expect it , and that friends is just a dab less than ideal! Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted November 30, 2015 Share Posted November 30, 2015 On 11/29/2015, 5:09:23, Mikey98118 said: Buzzkill, I just wrote you a lengthy reply, which promptly disappeared into cyberspace when I pressed "Submit Reply." So this one will be short. Methane is rated about one-half as effective at heating as other fuel gases. Water formation in the secondary flame is the reason given for this inconvenient fact. I've used methane heating torches, which put out really impressive looking flames, and can tell you from first hand experience that the poor heating performance quoted is so. This information is all available on the web. Mikey My response disappeared too. Please understand that I'm not doubting your research or experience. I have very little and you've written at least one book, so I value the information you give far more than my recollection from chemistry classes a couple decades ago. I do like to understand how and why things are the way they are though, which is why I'm pursuing this. Quote Link to comment Share on other sites More sharing options...
Charlotte Posted November 30, 2015 Share Posted November 30, 2015 On 11/29/2015 3:48:09, Mikey98118 said: Charlotte, Methane's theoretical flame temperature is nearly the same as propane; not its proven heating value, which is about one-half. Both the CO and H2 combustion are heat producing, so minor heat is added in the secondary flame. Formation of the H2O leaches heat from the secondary flame; it does not produce heat. Should have I underlined the word NET? Quote Link to comment Share on other sites More sharing options...
Frosty Posted November 30, 2015 Share Posted November 30, 2015 On 11/29/2015, 2:53:12, ianinsa said: This is a very interesting debate and makes for a good read! I have been playing around with my Umo burners introducing LPG at different places and adding 'turbulence impellers ' etc. One thing I have found though is when adding the gas to the Intake of the blower you can get a serious "big dog effect" ie. Attention getting, trouser whetting "Woof' just when you don't expect it , and that friends is just a dab less than ideal! One of our guys has a propane gun burner that was designed to introduce propane at the impeller and it works a treat. Unfortunately they aren't being made anymore nor are parts available. <sigh> A good pants wetting WOOF is a good way to keep visitors on their toes don't you think? Frosty The Lucky. On 11/29/2015, 1:12:07, Mikey98118 said: Frosty, I think we're talking apples and oranges. For one thing you seem to be thinking along the lines of vortical flow in an expanding tapered mixing tube, which will produce some effects that I'm speaking of, but will reverse others. I'm recommending producing spin (not push) at the large opening of a funnel; that funnel's small opening connects to the rear end of a burner's mixing tube. One facet of vortical flow (speeding forward motion of the mix my way, and slowing it your way) are opposite effects of the same principle used in reverse; same principle but different applications. Better mixing and and lowered flame nozzle pressure will happen both ways. I don't find one method superior to the other; I see both of them proving useful, so long as they are applied deliberately. Mikey Like I said I need a pic or diagram to get a handle on what you're doing. Speculating before I have more than a vague idea is something I gripe about others doing so I TRY not to. I find myself saving posts before submitting and if it disappears into the IPSphere I try pasting and resending. You have to keep your history cleared out too or the cookies IPS plants on us sucks up our bandwidth and our connections time out. Frosty The Lucky. Oh yeah IPS automatically merges your posts too. I do SO love it when some basement geek IT thinks for me. Quote Link to comment Share on other sites More sharing options...
Charles R. Stevens Posted December 1, 2015 Share Posted December 1, 2015 No offence, but even book writers can be wrong. I am not claiming that Mike is wrong, but even before the internet I have seen plenty of BS printed as fact in books. So that said, one should be encoraged to ask, and fact check. I think Mike and the other authors that freqent this site would agree. Especialy when one can pester the author Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted December 22, 2015 Share Posted December 22, 2015 Buzzkill, Never back off because the other guy wrote a book, has expert standing, or even a PHD. Let your facts stand tall or fall on their merit, and don't be over impressed with anyone else. I have been thinking about, designing, and running burners and heating equipment for sixteen years, and am still learning obvious things I've overlooked! When Gas Burners hit the book shelves, people on my groups lost all their precious disrespect and healthy skepticism. I had to start using my wife's pet name for me (Mikey) or lose all my antagonists; a terrible fate! Listen to Charles; he has it right. So, don't drive me to extremes. Mikey was plenty bad enough! Quote Link to comment Share on other sites More sharing options...
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