The Effect of Hydrogen on Open Flame Combustion

Open flame combustion is the result of a chemical reaction that produces heat and sometimes light, when fuel, oxygen and heat are brought together in the right proportions. Combustion will only start, and be self-sustaining, if the proportions of fuel and oxygen are within certain limits.

Flame

When open flame combustion takes place, the visible flame we see is the result of a chemical reaction between hydrogen in the fuel and oxygen. If no hydrogen is present, no flame is visible; this is the reason coal that has been deprived of all its hydrogen -- in other words, coke -- yields no flame.

Hydrogen

Hydrogen is not combustible. This can be demonstrated in the laboratory by passing a lighted taper into an inverted jar containing pure hydrogen; the taper is extinguished.

Explosion

However, a mixture of hydrogen and oxygen will combust explosively in the presence of an ignition source, provided that neither gas is present in large excess. The oxidation of hydrogen, to produce water vapor, liberates a vast amount of energy, causing the water vapor to expand rapidly.

References

• National Center for Forensic Science: Types of Combustion
• University College Cork: Hydrogen
• The Penny Magazine of the Society for the Diffusion of Useful Knowledge; Charles Knight: 1838