Gas burner

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Propane burner used with forced air into a metal melting furnace.
Propane burner with bunsen flame.
Propane oxygen burner used for cutting through steel rails.
Flame of a Gas- and Oil dualburner.

A gas burner is a device to generate a flame to heat up products using a gaseous fuel such as acetylene, natural gas or propane. Some burners have an air inlet to mix the fuel gas with air to make a complete combustion. Acetylene is commonly used in combination with oxygen.

It has many applications such as soldering, brazing and welding, the latter using oxygen instead of air for getting a hotter flame which is required for melting steel. For laboratory uses a natural gas fired Bunsen burner is used. For melting metals with melting points of up to 1100 °C such as copper, silver and gold a propane burner with natural drag of air can be used.

Table 1: Flame temperatures of common gases and fuels[edit]

Gas / Fuels Flame temperature
Propane in air 1980 °C
Butane in air 1970 °C
Wood in air (normally not reached in a wood stove) 1980 °C
Acetylene in air 2550 °C
Methane (natural gas) in air 1950 °C
Hydrogen in air 2111 °C
Propane with oxygen 2800 °C
Acetylene in oxygen 3100 °C +
Propane-butane mix with air 1970 °C ~
Coal in air 1900 °C (blast furnace)
Cyanogen (C2N2) in oxygen 4525 °C
Dicyanoacetylene (C4N2) in oxygen 4982 °C (highest flame temperature)

Info & Assuming:

  • Adiabatic flame
  • 20 degrees Celsius 1 bar atmosphere
  • Complete combustion (no soot and more blue-like flame is the key) (Stoichiometric)
  • Peak Temperature
  • Speed of Combustion (has no effect on temp, but more energy released per second (as adiabatic) compared to normal flame)
  • Spectral bands also affect colour of flame as of what part and elements of combustion
  • Blackbody radiation (colour appearance only because of heat)
  • Atmosphere - affects temperature of flame and colour due the atmospheric colour effect

Table 2: Explosive limits and ignition temperatures of common gases[edit]

Explosive limits (lower & upper, in %) Ignition temperatures
Natural gas 4.7 & 15 482-632 °C
Propane 2.15 & 9.6 493-604 °C
Butane 1.9 & 8.5 482-538 °C
Acetylene 2.5 & 81 305 °C
Hydrogen 4 & 75 500 °C
Ammonia 16 & 25 651 °C
Carbon monoxide 12.5 & 74 609 °C
Ethylene 3.4 & 10.8 490 °C

Note: Atmosphere is air at 20 degrees Celsius.

Table 3: Combustion values of common gases[edit]

Gas Combustion value
(Btu/ft³) (MJ/m³)
Natural gas (methane) 950 to 1,150 35 to 43
Propane-butane mix 2,500 to 3,200 90 to 120
Propane 2,572 95.8
Butane 3,225 120.1

See also[edit]

References[edit]

  • Pocket Guide to fire and arson investigation, second edition, FM Global, Table 1,2 and 3