Lignite is dark brown, the content of carbon is 25-35%, the amount of moisture is up to 66%, the ash content is 6%-19%. Its calorific heat is 10-20 MJ/kg.

 

Lignite with high volatile is easier to liquefy or gasification. However, because it contains more water, and easy to self-ignite, will increase transport and storage costs, so rarely circulates in the market. Generally near the lignite mine, construct the power plants, direct regard it as fuel. The emission of pollutants in lignite power plants is larger than that of ordinary coal, especially with open-pit coal mines, which often cause the judgement of environmentalists.

 

Drying lignite equipment are mainly: rotary drum dryer, disc dryer,tower dryer etc.

The thermal medium for drying brown coal are mainly: Steam pyrolysis type, Steam Thermal Conductive type, Direct flue gas to heat spread type etc.

 

Taking into account the quality index and the economic operation index, Dongding is currently using direct flue gas to heat spread type rotary drum dryer.

 

The main problems for drying lignite: 

 

1.Flammable and explosive

 

2.Easy to absorb humidity

 

Dongding through anaerobic drying, no fire entry, control of dust concentration, solve flammable and explosive problem; By increasing the drying temperature of lignite, its internal structure changes, that is, tar migration, clogging its pores, Dongding solved the second problem.

 

Therefore, in the current environment of increasing global energy tension, the economic value of lignite and its related processing and production technology has been re-valued by the world Energy Community, so the development of lignite drying and extraction technology and equipment is the key to clean and effective utilization of lignite.