A colorless, flammable gas with an odor similar to garlic, Acetylene was discovered in 1836, when Edmund Davy was experimenting with potassium carbide. Approximately 20 percent of acetylene is consumed for oxyacetylene gas welding and cutting due to the high temperature of the flame. Is widely used as a fuel and a chemical building block and is mainly manufactured by the partial combustion of methane. It Appears as a side product in the ethylene stream from cracking of hydrocarbons. An acetylene molecule is composed of two carbon atoms and two hydrogen atoms. The two carbon atoms are held together by what is known as a triple carbon bond. There are two basic conversion processes used to make acetylene: One is a chemical reaction process, which occurs at normal temperatures, the other is a thermal cracking process, which occurs at extremely high temperatures.