Coal classification
The coal ranks
This article is dedicated to the coal ranks and their differences. There are the following coal ranks:
A - anthracite coal
Б - brown coal
Г - gas coal
OC - forge coal
CC - low-caking coal
T - semi-anthracite coal
Д - long-flame coal
Ж - fat (bituminous) coal
К - coke coal
There are 17 ranks of coal: «Д», «ДГ», «Ж», «КЖ», «Г», «ГЖО», «ГЖ», , «К», «КО», «КСН», «КС», «ОС», «ТС», «СС», «Т» «АМ», «АО», «АС», «АК», «АКО», «АШ»»Б1», «Б2», «Б3». According to concentrating coals can be divided into:
- middlings (metallurgy);
- concentrates (our energy for power stations);
- tailing - for people and coal pelletising;
The oxidation is shown with the following abbreviations - OK, OK2, OK1
Anthracite coal fraction marking:
П - lump coal (>=100 mm);
AK - large (50-100 mm)
AKO - fist-nut coal (25-100 mm);
AO - nut coal (25-50 mm)
AM - small (13-25 mm)
AC - pea-coal (6-13 mm);
АШ - dust coal (0-6 mm);
Р - alltogether coal (0-200 mm);
open pit coal - 0-300 mm
There can also be mixed ranks. For example, ГКОМ (K - 50-100, O - 25-50, M - 13-25) is approximately 13-100 mm. If we speak about the process of coal creation (called metamorphism), the coals can be divided into the following groups - hard coals, brown coals and anthracites. Anthracite coal produces the most heat during the burning process. For energy industry of Russia hard coals are the best as they have the best ratio of cost to produced heat. For example, the coals of Д and Г ranks transmit much heat and can burn without additional airflow. They are often used in boiler stations. On the contrary such coals as CC, T and OC are mainly used in power industry. The reasoning of such ranks of coal is justified by the volumes, as the burning process requires increased expenditure. In order to manufacture steel and iron-cast usually Г and Ж coal ranks are used.
A-rank - anthracite. Large anthracite fractions are usually used in utility sphere of Russia. They are very popular and highly used by people everyday. Also this rank is wide-spread in the power industry due to the high temperature of burning.
Б-rank - brown coal. The volatile components output is more than 45%. According to humidity level they can be divided into 1 Б (more than 43%), 2 Б (29-45%), 3 Б (up to 32%).
Coking coal rankings
Д-rank - long-flame coal. Has bad caking properties. As well as A rank coal, can be used both in power industry and in chemical industry.
ДГ-rank (long-flame gas coal). On the contrary, has high caking level and low level of fragility. The coke from this coal type is not suitable for further use as it has high reaction capacity and low durability.
Г-rank (gas coal). It is mainly use in utility sphere as a cheap substitution for A-rank coal. It has properties that allow it to be used in coke moulding, semi-coking process. It is divided into the following technological groups: vitrinite and inertinite. Low-ash variant is used to get synthesized oil.
Ж-rank (fat coal). It is one of the most valuable coking coal types. The coke from this type of coal has enhanced structural durability.
ГЖО-rank (gas fat lean coal). It is a great product for coking. It can be used for utility purposes, if the coal is fusinite. This coal type is not suitable to get coke for metallurgy.
К-rank (coke coal). The main application area is getting of metallurgy coke. This type of coal is not mixed with any other.
КЖ-rank (coke fat coal). It is widely known that this type of coal is used in coke-chemical industry. It has the best coking index and allows to get methcoke from it. It has the following attributes:
CC - low-caking coal. Has wide application in power plants, boiler stations and utility sphere
T - semi-anthracite. One of the most important properties is complete inability to cake. Is valuable in power industry and utility sphere.
Coal is divided into ranks in order to use it more effectively in industry. Coal is divided into ranks and technology groups that are formed according to parameters and behaviour of coal during the thermal influence.
Coal rank Abbr. Volatile components Carbon lvl, Caloric value, Reflectivity in
output, Vg, % Cg,% kcal/kg oil immersion, %
Brown Б 41+ 76 and less 6900-7500 0,30-0,49
Long-flame Д 39+ 76 7500-8000 0,50-0,64
Gas Г 36 83 7900-8600 0,65-0,84
Fat Ж 30 86 8300-8700 0,85-1,14
Coke K 20 88 8400-8700 1,15-1,74
Forge OC 15 89 8450-8780 1,75-2,04
Semi- T 12 90 7300-8750 2,05-2,49
Anthracite
Anthracite A <8 91+ 8100-8750 2,50-6,00
Besides the data presented in table there might be some additional ranks, according the the sort. Such ranking is conditional and shows the groups of coal fulfilling different demands. This means there may be quite a lot of such conditional ranks. The classification according to genetic and technological parameters is considered to be the most universal. However it is used for generic coal evaluation. If we speak about the coal that has to be used in heat-power engineering the following naming scheme is used. Rank = type + chunk size.
Group Class Conditional naming Chunk size limit
lower upper
lump П 100(80) 200...300 Large (fist) К 50(40) 100(80) Nut О 25(20) 50(40) Sort Small M 13(10) 25(20) Pea C 6(5..8) 13(10)
Dust Ш 0 6(5..8)
Large/Lump ПК 50(40) 200..300
Large/Nut KO 25(20) 100(80) Small/Nut OM 13(10) 50(40) Pea/Small MC 6(5..8) 25(20)
Combined Pea/Dust СШ 0 13(10)
Small/Pea/Dust МСШ 0 25(20) Nut/Small/Pea/Dust ОМСШ 0 50(40) Rough coal P 0 200..300
For example, the coal of ГР rank means that we have a gas rough coal (with chunk size of 0-200...300mm). In this case the proportion of each coal rank may be very different. It may be the coal consisting from 90% of big chunks and 10% of dust and vice versa. If you see ТПК abbreviation, this means semi-anthracite coal, sorted with chunk size from 50 (40) to 200...300 mm. The proportion of small (less than 50 mm) chunks should not be more than 15%.