What is the difference between coal gas, natural gas, and liquefied gas?

The combustion gas sources in our lives are roughly divided into three categories: liquefied petroleum gas (Y), artificial coal gas (R), and natural gas (T).

Liquefied petroleum gas (abbreviated as liquefied gas) is a kind of petroleum tail gas left in the process of refining gasoline, kerosene, diesel, heavy oil and other oil products. Through a certain procedure, the petroleum tail gas is recycled and reused, and pressurized measures are taken to make it liquid and packed in a pressurized container. The name of liquefied gas comes from this. Its main components are ethylene, ethane, propylene, propane and butane, etc., which are liquid in the gas cylinder. Once it flows out, it will vaporize into a flammable gas about 250 times the original volume, and it is very easy to spread. It will burn or explode when encountering an open flame. Therefore, special attention should be paid to the use of liquefied gas.

Coal gas is made from solid raw materials such as coal or coke through dry distillation or vaporization. Its main components are carbon monoxide, methane and hydrogen. Therefore, coal gas is toxic and easy to form an explosive mixture with air, so it should be used with great caution.

Natural gas is a general term for naturally formed gases buried in the strata. However, the natural gas usually refers to a combustible gas rich in hydrocarbons stored in the deeper part of the strata, and the natural gas that coexists with oil is often called oil field associated gas. Natural gas is transformed from organic matter billions of years ago. Its main component is methane. In addition, according to different geological formation conditions, it also contains different amounts of low-carbon alkanes such as ethane, propane, butane, pentane, hexane, and non-hydrocarbon substances such as carbon dioxide, nitrogen, hydrogen, and sulfides; some gas fields also contain helium. Natural gas is an important energy source, widely used as city gas and industrial fuel; in the 1970s, natural gas accounted for about 18% to 19% of the world's energy consumption. Natural gas is also an important chemical raw material.

The calorific value of natural gas per cubic meter is 8000 kcal to 8500 kcal.

The calorific value of liquefied gas per kilogram is 11000 kcal. The specific gravity of gaseous liquefied gas is 2.5 kg/cubic meter. The calorific value of each cubic meter of liquefied gas is 25,200 kcal. This shows that the calorific value of one cubic meter of liquefied gas is three times that of natural gas, but there are also reports that the calorific value of liquefied gas is 7 times that of natural gas.

Each bottle of liquefied gas weighs 14.5 kilograms, with a total calorific value of 159,500 kcal, which is equivalent to the calorific value of 20 cubic meters of natural gas.