煤炭进化史coal evolution(2003)

一个名字，几个品种并非所有的煤都是一样的。事实上，煤是由这样一种复杂的混合物组成的，它可能在不同的矿床中有很大的不同。一些被称为冶金煤或炼焦煤的煤炭矿床是炼钢所必需的。其他被称为热煤或蒸汽煤的沉积物被用来发电和制造水泥。煤炭矿床的差异来自形成矿床的原始植物材料和产生煤炭的过程的差异。不同植被类型和矿物含量的变化影响煤的组成。更高的压力和温度也影响了矿床的质量，以及形成时间的长短。碳含量越高，排名越高在北美，煤是按等级分类的。等级较高的煤含有更多的碳，产生更多的能源。无烟煤*是排名最高的煤，因为它的含碳量最高，因此它的热值最高。无烟煤也是所有煤中最坚硬的。尽管目前加拿大还没有开采无烟煤，但在不列颠哥伦比亚省西北部的偏远地区已经发现了无烟煤矿床。烟煤是无烟煤的一种。它的碳含量高，通常含水量低，并且含有少量的氢和氧。这种成分使烟煤成为冶金和热力方面的理想材料。2001年，烟煤占加拿大煤炭总产量的48%以上。其中84%用于冶金用途。加拿大不列颠哥伦比亚省、阿尔伯塔省和大西洋省有烟煤矿床，育空省、西北地区和努纳武特省有少量烟煤矿床。次烟煤*煤的等级较低，比烟煤更软，含水率较高。它非常适合用于火力发电厂。2001年，亚烟煤的产量占加拿大总产量的35%。褐煤*是所有煤中排名最低的。与其他煤相比，褐煤比较软。它的颜色从深黑色到各种深浅不一的棕色。位于萨斯喀彻温省南部和阿尔伯塔省东南部的褐煤为萨斯喀彻温省提供了65%的电力。

ONE NAME, SEVERAL VARIETIES 

All coal is not created equal. In fact, coal is composed of such a complex mixture of materials, it can be quite different from one deposit to another. Some deposits of coal, called metallurgical* or coking coal, are essential for use in steelmaking. Other deposits, called thermal* or steam coal, are used to generate electrical power and make cement.
Differences in coal deposits came from variations in the original plant materials that formed the deposit and in the process that creates coal. Different kinds of vegetation and variations in the amount of minerals influenced the composition of coal. Higher pressures and temperatures also affected the coal deposit’s quality, as did the length of time it spent being formed.

THE HIGHER THE CARBON CONTENT, THE HIGHER THE RANK 

In North America, coal is classified by rank. Higher ranked coal contains more carbon and produces more energy.
ANTHRACITE* is the top-ranked coal because it has the highest carbon content and, therefore, the most heat value.  Anthracite is also the hardest of all coals.  Although it is not currently being mined in Canada, anthracite deposits have been found in remote areas of northwestern British Columbia.
BITUMINOUS* coal is a step down from anthracite. It has a high carbon content, is generally low in moisture and has small amounts of hydrogen and oxygen. This composition makes bituminous coal ideal for both metallurgical and thermal uses. In 2001, bituminous coal accounted for over 48 per cent of Canada’s total coal production. Of that, 84 per cent was mined for metallurgical use. There are bituminous coal deposits in British Columbia,  Alberta and Atlantic Canada and minor amounts in Yukon, Northwest Territories and Nunavut.
SUB-BITUMINOUS* coal is lower ranked and softer than bituminous coal and tends to have high moisture content. It is well suited for use in thermal electric power generation plants. Mined in Alberta, sub-bituminous coal accounted for 35 per cent of Canada’s production in 2001.
LIGNITE* is the lowest ranked of all the coals. In comparison to other coals, lignite is quite soft. Its colour can range from a dark black to various shades of brown. Found in southern Saskatchewan and southeastern Alberta, lignite generates 65 per cent of Saskatchewan’s electric power.