Coking Gas
Coking Gas is a valuable material produced in the coke ovens used in the steel production industry. The by-product of heating coal without air, the gas is composed of hydrogen (H2), methane (CH4), and other hydrocarbons, carbon monoxide (CO), and some water vapor. Heavy cooling of the gas yields a liquid, which includes by-products such as ammonia, benzene, and heavier hydrocarbons (liquid coked gas) used in commercial products.
The process of generating coking gas starts with heating bituminous coal in the absence of air. This process is called destructive distillation which results in the formation of gaseous hydrocarbons. The chemical composition of the gas largely depends on the type of coal used, the chemical content of the coal, and the temperature of the process. The gas that is generated is a “dirty” gas and requires a great deal of cleaning before it is suitable for a variety of uses in the steel industry. The cleaning process removes the sulfur, tar, and other pollutants from the gas.
The formation of the gas follows a “pyrolysis” reaction which is the breakdown of organic compounds caused by heat. As the coal is heated, it releases volatile gases and various condensable molecules. These molecules eventually condense and form a liquid known as liquid coked gas (LCG). This LCG is then further processed to be used as binder material in coke making, as fuel for furnaces and ovens and for many other industrial purposes.
When it is used as a fuel, the coking gas is mixed with other components such as oxygen, steam, and nitrogen to provide specific properties. The term “regulation mix” refers to the amount of steam and nitrogen added to the gas before it is introduced into the boilers. The amount of regulation mix will depend on the particular fuel and the desired heat output.
Coking gas has a higher energy content than any other fuel and is about twice as efficient as natural gas. It is ideal for high temperature applications owing to its slow burning rate and the fact that it produces virtually no sulfur dioxide. It also has a lower cost when compared to natural gas and its use is encouraged in some countries to help reduce emissions of greenhouse gases.
Coking gas is a beneficial by-product of the steel production industry and it has numerous applications. When properly cleaned and processed, coking gas can give better results than many traditional fuels. Its usage reduces emissions and adds to the green energy scenario. Its production, handling and utilization require specialized expertise and equipment, so trained professionals should be consulted before handling coking gas.
