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1. Popular types of coal on the market

Current coal can be divided into 4 popular types of coal below: 

Brown coal (lignite coal)

It is the youngest solid rock formed about 50 million years ago from peat or lignite, which is based on its color, which ranges from reddish brown to black. It can be understood as "unripe" bituminous coal. Lignite color is brighter than high-grade coal, crumbly texture and high moisture content.

Brown coal is considered a fuel with a low level of charring (metamorphosis). It contains at least 50% carbon, many volatiles, mineral impurities and moisture, so it burns more easily, creating a lot of smoke and a burning smell. The efficiency of volatiles is up to 50%. Ash content is about 6 - 19%. It gives off less heat. The heat of combustion is only about 4000 - 5500 Kcal/kg. However, with its low cost and availability, brown coal is still an attractive fuel for the power and energy production industry.

Coking coal (bitumen)

Bituminous coal, also known as coking coal, contains 45%-86% carbon, with an ash content of up to 12% by weight. Bituminous coal is formed from the compression process of brown coal, old, black and dark brown sub-bituminous coal. Bituminous coal structures are clear, light-colored bands, which are dark materials in coal seams. The main components are macerals, vitrinites and liptinites.

The carbon content in bituminous coal is about 60-80%, the rest is Hydrogen, water and sulfur. Bituminous coal is used for electricity generation and is an important raw material for coking coal production in the iron and steel industry.

Thin coal (sub-bitumen, black lignite)

Sub-bituminous coal, also known as black lignite coal, exists in material between bituminous coal and lignite coal. Charcoal is dark brown, black and brighter than lignite coal, with a wood grain structure.

Sub-bituminous coal exists in a dry state, without ash, containing about 42 - 52% carbon, with a heat content of about 19-26%, lower than bituminous coal.

Anthracite coal

Anthracite coal is black, metallic and sometimes iridescent, appearing in multi-layered rock strata. Anthracite coal is the result of a long-term impact on temperature and pressure of bituminous coal. The main ingredient is carbon with a content of up to 86-97%, the highest among all types of coal.

This type of coal has no flame, is difficult to burn and requires strong ventilation to burn. It has the ability to generate greater heat and high heat capacity. Anthracite coal can be left piled up for a long time because it does not spontaneously combust, has high mechanical strength, and does not crumble during transportation. In addition, the combustion products of this fuel have no odor. Anthracite coal is considered "old" coal, with much higher value than other types of coal. Therefore, it is applied in many industries, especially energy and thermal power.

2. What type of coal should be used?

Each type of coal has its own characteristics and roles. If peat is often used for agricultural and forestry exploitation, coal is a raw material that plays an important role in the energy, thermal power, metallurgy, and fertilizer industries...

In addition, depending on coal reserves, resources as well as production areas, businesses will use domestic or imported coal to ensure reserves, quality and price.

3. Application of coal in industry

Among the current types of coal, coal is used the most in the following industries:

• Used in the energy industry: Coal is exploited as solid fuel for electricity production and combustion. Coal is ground into powder and burned in boilers. The emitted heat will convert water in the boiler into steam for use in manufacturing plants such as chemical: textile, paper, beverage...
• Electricity production field: The most important application of coal is to generate electricity. Coal is used to create steam to turn turbines and generators to produce electricity. Coal power accounts for 37% of the world's electricity.
• Used in gasification technology: Coal gasification is used in the production of syngas, including carbon monoxide and hydrogen gas. This gas source is mainly used to burn turbines, produce electricity, and a small part is converted into gasoline, diesel fuel or to produce fertilizers and chemical products...
• Used in metallurgy: When metal melts in the mold, coal is burned slowly to release gas, reducing pressure. This will prevent the metal from entering the voids of the sand. Coal is processed into coke.
• Used in construction: Coal and by-products after combustion such as ash and slag also play an important role in the concrete and cement industry.

Coal is a limited and non-renewable energy source. According to the Energy Institute, Vietnam is currently implementing its commitment to reduce emissions in COP26 commitments, eliminating coal heat by 2050. However, the role of coal will still be very important in the next 27 years.

Maintaining a stable coal source to meet the needs of iron and steel production, cement, mining, paper production, and chemicals is essential. Factories need to have a stable, quality coal supply. At the same time, it is necessary to gradually shift energy to other forms of renewable energy, such as from waste products from the agriculture and forestry industry, in order not to disrupt production.