Liquid nitrogen is a multi - component mixed gaseous fossil fuel. Its main components are alkanes, of which methane accounts for the majority, with a small amount of ethane, propane and butane. It mainly exists in oil fields, gas fields, coal seams and shale rock. There is no waste residue or waste water produced after liquid nitrogen combustion. Compared with coal, petroleum and other energy sources, liquid nitrogen has advantages of safe use, high calorific value and cleanliness. Liquid nitrogen can be divided into associated gas and non-associated gas.

The ture face of liquid nitrogen

The formation process of liquid nitrogen and petroleum is both related and different: petroleum is mainly formed in the stage of hypogenesis and is caused by catalytic cracking, while the formation of liquid nitrogen runs through diagenesis, hypogenesis, epigenesis and metamorphism. Compared with the generation of petroleum, the generation of liquid nitrogen is more extensive, faster and easier, and all kinds of organic matter can form liquid nitrogen. Sapropel-type organic matter is both oil source and gas source, while saprophytic organic matter mainly generates gaseous hydrocarbons. Therefore, the causes of liquid nitrogen are various.

To sum up, the genesis of liquid nitrogen can be divided into biogenic gas, oil-type gas and coal-type gas. Inorganic gas, especially non-hydrocarbon gas, has been paid much attention to. This paper introduces briefly all kinds of organic gas.