A Bic produces a "premixed laminar flame" (the flame's fuels mix with oxygen before burning and retain a relatively steady shape).



"Although a lighter or candle flame appears to be a solid mass of light, it's actually hollow - the luminous outer layer is typically less than 1 mm thick. The core of the flame consists of the fuel gas and air pushing steadily outwards in the "flame" shape until they reach the thin combustion zone. The hottest portion of the flame typically is in and immediately outside this zone, which is filled with the immediate products and partial-products

of the chemical reaction known as combustion.



Which part of the combustion zone is the hottest? Peak temperatures are more uniform than you might expect along the length of the flame. Measurements of a 79 mm methane flame, a 107 mm methane flame, and an 88 mm ethylene flame (see Santoro

below) all generally showed slightly higher temperatures (by 20-50 degrees K) near the base. Pitt's work cited below shows substantially the same thing and has some nice graphs of temperature versus height along the flame.



Not to be outdone by Pitt, I took Santoro's

measurements of a symmetrical methane flame, which were available in a spreadsheet file on the National Institute of Standards and Technology website, and generated a graph showing the temperature versus the distance from the centerline

of the flame. Several temperature curves are shown, measured at different heights above the flame's base. The magenta curve corresponds to a level near the base of the flame, and the light blue curve corresponds to a level near the tip. You can see from the graph that the peak temperatures at the top of the flame are slightly lower than those at the middle and base.



Temperature is only part of the equation, though. More relevant if you're trying to light a fire is the total heat available at different spots in the flame. That's a function of the volume of fuel and air and the temperature. In graphical terms, you're looking for the part of the flame with the most area under the curve. In a typical flame that's near the tip - look at the area under the curve of the 70 mm line compared to the other lines. Why is there more heat in the tip? Because the non-burning

center of the lower part of the flame is relatively cool, whereas all of the tip is aflame and thus uniformly hot throughout.



Provided your backyard lighter flame is free of contaminants that might skew the color, a slightly lean violet-blue

flame is the hottest. Blue-violet

=

high frequency =

high energy =

high temperature. A white flame has its visible radiation energy spread out more evenly across the spectrum and isn't peaking on the high-energy

blue end. That indicates lower overall energy, and thus lower temperature, than a blue flame.



* Many thermodynamics and chemistry texts state that adiabatic flame temperature is highest when the flame is at perfect stoichiometry

(exactly enough air to burn the fuel). Since mixing and other practical effects require extra air to ensure combustion, the hottest flames in practice tend to be slightly lean (slightly more oxygen than needed)."



"The temperature of a Bic lighter flame is 1977C or 3590.6F. Wow, that is hot! Be careful and ChaCha

again!"



Edit: by Urvile



----------------------------------------------



The above has some correct information, but the temperatures is gives are ridiculous. The melting point of wrought iron is only 1500C. A bic

lighter CANNOT melt wrought iron. Go ahead. Give it a try.



The fuel in a standard BIC lighter is butane. Even in "Jet" style lighters (highly air enriched) these only go to around 1200C-1300C typically.



In as perfect, adibiatic

and stoichiometric

reaction, occurring at 1 atmosphere at 20C, you would get a temp of 1970C. - That means no excess fuel, no excess air, everything in exact proportions for maximum temp. I.E.,,

it is the maxmimum

theoretical temperature butane could burn at under ideal conditions.



That is NOT what you get in a standard BIC lighter, which has a rather anemic fuel/air mix.



Though the exact temperature will depend on many variables, pressure, temp, type of lighter, quality of fuel, etc., we know the auto-ignition

temperature of butane is 288 °C.

This is the temperature at which butane will ignite itself with no outside ignition source (fire, spark, etc.).

So this is probably going to be a likely stable reaction temperature for the typical weakly oxygenated lighter.



And depending on conditions, once lit, a standard BIC lighter will probably continue to burn at around ~450C - to probably around ~800C, again, depending on how oxygenated it is.



The more oxygenated, the more "blue" the light spectrum it burns at. I.E.,

the more yellow flame will be lower temp, but the bluer the flame the hotter.