British coals classification

An example is the classification scheme used by British Coal, and is common throughout the UK. The scheme divides coals into groups, generally as shown in Table 15.6. The group, grading and modes of preparation of a coal serve to indicate the usage for which the coal is suitable for application with industrial boilers. For grading of coal the nominal sizes are shown as follows ... 

British system of coal classification used by the National Coal Board (15). ... 

The ASA-ASTM system established four classes or ranks of coal anthracite, bituminous, sub-bituminous, and lignite, based on fixed-carbon content and heating value measured in British thermal units per pound (BTU lb ). Anthracite, a hard black coal that burns with little flame and smoke, has the highest fixed-carbon content, 86-98% and a heating value of (9.2-10.7) 10 J kg (Speight 2006, see Tables 2.51 and 2.55). This classification was already used 100 years ago (Robertson 1919) and Seyler (1900) used the C/H ratio for the coal classification, from lignite ( 10) to anthracite (>26). Based on raw coal, the chemical composition varies widely (in %) ... 

The earlier illustrations indicate that, with the exception of perhaps the geological classification and the banded structure classification system, coal classification can be a complex operation. While only the major classification systems (especially those relevant to the North American and British scenarios) have been illustrated in detail, there are, nevertheless, other systems which have in the past been used in various other countries. Indeed, these other systems for the classification of coal may still find use in the countries of their origin. No attempt has been made to illustrate these systems in the present context, but they are certainly very worthy of mention as an indication of the nomenclature and terminology applied to coals of the various types. 

In addition to the above-mentioned classification there exist numerous others including those adopted by the European Economic Community (EEC) and the British Coal Board. For an informative discussion on these the reader should consult Brame and King [89]. 

This classification does not include a few coals, principally nonbanded varieties, that have unusual physical and chemical properties and that come within the limits of the fixed-carbon or calorific value of the high-volatile bituminous and subbituminous ranks. All of these coals either contain less than 48% dry, mineral-matter-ffee fixed carbon or have more than 15,500 moist, mineral-matter-free British thermal units per pound. 

One classification of coal is by rank, i.e., according to the degree of metamorphism, or progressive alteration, in the natural series from lignite to anthracite. In the ASTM classification, the basic criteria are the fixed-carbon content and the calorific valnes (in British thermal units) calcnlated on a mineral-matter-free basis. 

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