Gas burner

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Propane burner used with forced air into a metal melting furnace.
Propane burner used with forced air into a metal melting furnace.
Propane burner with bunsen flame.
Propane burner with bunsen flame.
Propane oxygen burner used for cutting through steel rails.
Propane oxygen burner used for cutting through steel rails.

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.

Contents

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

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 2055 °C
Propane with air (in air) 1995 °C
Propane with oxygen 2800 °C
Acetylene in oxygen 3100+ °C
Hydrogen with air (in air) 2111 °C
Propane-butane mix with air (in air) 1225 °C
Coal in air 1900 °C (blast furnace)
Cyanogen (C2N2) in oxygen 4525 °C
Dicyanacetylene (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)
  • 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 effect colour of flame as of what part and elements of combustion
  • Blackbody radiation (colour appearance only because of heat)
  • Atmosphere - effects temperature of flame and colour due the the atmospheric colour effect

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

Explosive limits (lower & upper) Ignition temperatures
Natural gas 4.7 & 15 482 to 632 °C
Propane 2.15 & 9.6 493 to 604 °C
Butane 1.9 & 8.5 482 to 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 celsius.

[edit] Table 3: Combustion values of common gases

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

[edit] See also

  • Flame
  • Pocket Guide to fire and arson investigation, second edition, FM Global, Table 2
  • Gas welding