One Question per Day (January 23, 2018)

Low-grade coal refers to coal with a degree of coalification lower than that of anthracite, and its ash-free volatile matter on a dry basis is higher than 10%~20%. Compared to bituminous coal, subbituminous coal is more difficult to ignite and burn; it produces a short flame during combustion, has poor caking properties, and its calorific value lies between that of anthracite and ordinary bituminous coal. Lean coal: It has a low volatile content and poor caking property, and can be used alone for coke production. When mixed with other coal types suitable for coking, the inclusion of lean coal will increase the size of the coke products. Lean coal can also be used for power generation, power plant boilers, and as a domestic fuel. Typical lean coal is produced by the Xishan Coal and Electricity Company in Shanxi Province. 9 N7 U; h* V8 s6 t9 yPower Alliance|Thermal power|Fossil fuel power|Nuclear power|Hydropower|Standards|Energy|Energy conservation Thin coal: Moderate volatility and cohesion, mainly used for coking. Some gums may be produced during the coking process, and the thickness of the gum layer is 6–10 mm. Coke produced by coking lean coal alone has high mechanical strength but relatively poor wear resistance. Apart from that portion of lean coal with high ash and sulfur content, lean coal is often mixed with other types of coal for coking.

Low-grade coal refers to coal with a degree of coalification lower than that of anthracite, and its ash-free volatile matter on a dry basis is higher than 10%~20%. Compared to bituminous coal, subbituminous coal is more difficult to ignite and burn; it produces a short flame during combustion, has poor caking properties, and its calorific value lies between that of anthracite and ordinary bituminous coal. Lean coal: It has a low volatile content and poor caking property, and can be used alone for coke production. When mixed with other coal types suitable for coking, the inclusion of lean coal will increase the size of the coke products. Lean coal can also be used for power generation, power plant boilers, and as a domestic fuel. Lean coal: moderate volatility and cohesion, mainly used for coking. Some gums may be produced during the coking process, and the thickness of the gum layer is 6–10 mm. Coke produced by coking lean coal alone has high mechanical strength but relatively poor wear resistance. Apart from that portion of lean coal with high ash and sulfur content, lean coal is often mixed with other types of coal for coking.

The ash-free basis volatile matter content (Vdaf) of lean coal, thin coal, and weakly lignitized coal all falls within the range of 10% to 20% – so how are they distinguished? Answer: Low-quality coal: non-caking or slightly caking, with a caking index G ≤ 5. Lean coal: caking index G 5-20; Thin coal: caking index G >20~65.

Bonding index G. G≤5 indicates low-quality coal, 20

The ash-free basis volatile matter Vdaf of low-quality coal is >10%–20%; it is non-caking or only slightly caking, with a caking index G ≤ 5. The ash-free basis volatile matter Vdaf of lean coal is >10%–20%, and its caking index G is >20–65. The ash-free basis volatile matter Vdaf of lean coal is >10–20%, and its bonding index G is >5–20.

Add a parameter: bonding index G. G≤5 indicates low-quality coal, 20

It can be distinguished based on caking property; the caking property of lean coal lies between that of weak coal and thin coal

The ash-free basis volatile matter Vdaf of low-quality coal is >10%–20%; it is non-caking or only slightly caking, with a caking index G ≤ 5. The ash-free basis volatile matter Vdaf of lean coal is >10%–20%, and its caking index G is >20–65. The ash-free basis volatile matter Vdaf of lean coal is >10–20%, and its bonding index G is >5–20.

Add a parameter: bonding index G. G≤5 indicates low-quality coal, 20