What Is Lignite?

Lignite, also known as wood coal (English: Lignite (coal); brown coal; wood coal), is the lowest degree of coal mineral coal. A brownish black, matte low-grade coal between peat and bituminous coal. Strong chemical reactivity, easy to weather in the air, difficult to store and transport, serious pollution to the air during combustion. However, because high-quality coal is almost mined out, lignite has become the main coal used in China. However, due to the low coalification of lignite, a large amount of black ash will float in the air during combustion. If it is not processed and refined, it will be used in large quantities The inferior lignite will cause the haze problem in China to become increasingly serious.

Because it is rich in volatiles, it is easy to burn and smoke.

Air-dried

Pyrolysis of coal refers to a complex process of a series of physical changes and chemical reactions that occur when the coal is continuously heated to a higher temperature under an inert atmosphere, also known as thermal decomposition or carbonization. Coal pyrolysis is an extremely important intermediate process in coal processing and transformation, such as combustion, gasification, and liquefaction. Compared with other coal conversion methods, the pyrolysis of coal is only a thermal processing process. At normal pressure operation, hydrogenation and oxygen are not required, and partial gasification and liquefaction of coal can be achieved to produce coal gas and coke. Compared with the gasification or liquefaction process, the coal pyrolysis process is simple, the processing conditions are mild, the investment is small, and the production cost is low.

The macromolecules of coal are rich in carbon and less in hydrogen. The pyrolysis process enriches the hydrogen in the coal into coke and gas, and at the same time obtains carbon-rich semi-coke.

Production by country (in millions of tons) ^[3]

country	1970	1980	1990	2000	2001
Germany	369.300	388.000	356.500	167.700	175.400
Russia	127.000	141.000	137.300	86.400	83.200
United States	5.400	42.300	82.600	83.500	80.500
Australia	24.200	32.900	46.000	65.000	67.800
Greece	8.100	23.200	51.700	63.300	67.000
India	twenty four	twenty four	twenty four	twenty four	twenty four
Poland	32.800	36.900	67.600	61.300	59.500
Turkey	4.400	15.000	43.800	63.000	57.200
Czech Republic	67.000	87.000	71.000	50.100	50.700
People's Republic of China	13.000	22.000	38.000	40.000	47.000
Yugoslavia	26.000	43.000	60.000	-	-
Serbia	-	-	-	35.500	35.500
Romania	14.100	27.100	33.500	17.900	29.800
Democratic People's Republic of Korea	5.700	10.000	10.000	26.000	26.500
Total	804.000	1,028.000	1,214.000	877.400	894.800

Open-pit brown coal mine near Gravenbroich, Germany

It is mainly used as fuel for power plants, and can also be used as chemical raw materials, catalyst carriers, adsorbents, sewage purification and metal recovery.

There are usually two:

(1) Brown lignite (loose coal), loose and soft texture;

(2) dark lignite (lignite), dense and hard texture. It can be directly used as fuel for household, industrial heat source and fuel for power generation. It can also be used as raw materials for gasification and low-temperature carbonization.

In some parts of the world, lignite is used as a fuel for heat sources and chemicals and as a feedstock for gas and liquid fuels. In the United States, first in the northern Great Plains (North Dakota, eastern Montana, northeast Wyoming, and northwestern South Dakota) and the Gulf Coast (Alabama, Arkansas, Kansas, Louisiana, Lignite was found in that state, Oklahoma, and Texas) and the Pacific Rim states (California, Oregon, and Washington).

China s lignite coal volume is only 211.8 billion tons, compared with the world s lignite coal resources (26229 billion tons), which accounts for about 24.4% of the world s total coal resources (107539 billion tons). %, Mainly distributed in eastern Inner Mongolia and eastern Yunnan, and a small amount in northeast and southern China.

Lignite has a low combustion value of 3,000 kcal or below. The latest development technology at home and abroad is lignite drying, which can increase its combustion value to 4800 or even 6000 kcal.