What is the difference between grade of coal and rank of coal?

Hi, I would say that rank refers to the degree of coalification.Plant matter buried under high pressure and temperature undergoes transformation-it becomes more dry,hard and more carbon rich gradually. read more

Bituminous: Bituminous coal is a middle rank coal between subbituminous and anthracite. Bituminous usually has a high heating (Btu) value and is the most common type of coal used in electricity generation in the United States. read more

Anthracite has the highest rank and has the highest carbon content,it’s pretty hard and lustrous. Lignite is the lowest grade coal with the least coalification. Talking about grade,my understanding is based on coal’s calorific value,ash content and moisture content. read more

Rank show the maturity of the coal from lignite to anthracite coal maturity increases while grade show the purity of the coal, it basically depends on total carbon . read more