Lignite

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Strip mining lignite at Tagebau Garzweiler near Grevenbroich, Germany

Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad, is the lowest rank of coal and used almost exclusively as fuel for steam-electric power generation. It is brownish-black and has a high inherent moisture content, sometimes as high as 66 percent, and very high ash content compared with bituminous coal. It is also a heterogeneous mixture of compounds for which no single structural formula will suffice.

The heat content of lignite ranges from 10 to 20 MJ/kg (9 to 17 million Btu per short ton) on a moist, mineral-matter-free basis. The heat content of lignite consumed in the United States averages 13 million Btu/ton (15 MJ/kg), on the as-received basis (i.e., containing both inherent moisture and mineral matter). When reacted with quaternary amine, amine treated lignite (ATL) forms. ATL is used in drilling mud to reduce fluid loss.

Because of its low energy density, brown coal is inefficient to transport and is not traded extensively on the world market compared with higher coal grades. It is often burned in power stations constructed very close to any mines, such as in Australia's Latrobe Valley and Luminant's Monticello plant in Texas. Carbon dioxide emissions from brown coal fired plants are generally much higher than for comparable black coal plants. The continued operation of brown coal plants, particularly in combination with strip mining and in the absence of emissions-avoiding technology like carbon sequestration, is politically contentious.^[1]^[2]

1 Types
2 Production
3 See also
4 External links
5 References

[edit] Types

Lignite can be separated into two types. The first is xyloid lignite or fossil wood the second form the compact lignite or perfect lignite.

Although the xyloid lignite may sometimes have the tenacity and the appearance of ordinary wood it can be seen that the combustible the woody tissue has experienced a great modification. It is reducible to a fine powder by trituration and if submitted to the action of a weak solution of potash it yields a considerable quantity of ulmic acid.^[3]

[edit] Production

Lignite mined in millions of metric tons:

		1970	1980	1990	2000	2001
1.	Germany	369,300	388,000	356,500	167,700	175,400
2.	Russia	127,000	141,000	137,300	86,400	83,200
3.	USA	5,400	42,300	82,600	83,500	80,500
4.	Australia	24,200	32,900	46,000	65,000	67,800
5.	Greece	8,100	23,200	51,700	63,300	67,000
6.	Poland	32,800	36,900	67,600	61,300	59,500
7.	Turkey	4,400	15,000	43,800	63,000	57,200
8.	Czech Republic	67,000	87,000	71,000	50,100	50,700
9.	People's Republic of China	13,000	22,000	38,000	40,000	47,000
10.	SFR Yugoslavia	26,000	43,000	60,000	-	-
10.	FR Yugoslavia	-	-	-	35,500	35,500
11.	Romania	14,100	27,100	33,500	17,900	29,800
12.	North Korea	5,700	10,000	10,000	26,000	26,500
...	Total	804,000	1.028,000	1.214,000	877,400	894,800