Coal Analysis
The methods generally used for specifying the analysis of coals has developed along pragmatic lines and are aimed at providing a useful guide to coal users rather than a purely chemical approach. The two types of analysis for any coal are the proximate analysis and the ultimate analysis.
Table 4-2 Classification of Coals |
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Class |
Volatile Matter |
Fixed Carbon |
Heating Value |
wt% |
wt% |
MJ/kg |
|
Anthracite |
<8 |
>92 |
36-37 |
Bituminous |
8-22 |
78-92 |
32-36 |
Sub-bituminous |
22-27 |
73-78 |
28-32 |
Browncoal (Lignite) |
27-35 |
65-73 |
26-28 |
Table 4-3 Classification of Coals |
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Class |
Fixed Carbon |
Heating Value |
Agglomerating Character |
|
wt% |
втшь |
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I. Anthracitic |
1. Meta-anthracitie |
>98 |
N onagglomerating |
|
2 Anthracite |
92-98 |
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3. Semianthracite |
86-92 |
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II. Bituminous |
1. Low-volatile bituminous coal |
78-86 |
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2. Medium-volatile bituminous |
69-78 |
Commonly agglomerating |
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coal |
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3. High-volatile A bituminous coal |
<69 |
>14,000 |
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4. High-volatile В bituminous coal |
13,000-14,000 |
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5. High-volatile C bituminous coal |
11,500-13,000 |
Agglomerating |
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III. Sub-bituminous |
1. Sub-bituminous A coal |
9,500-10,500 |
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2. Sub-bituminous В coal |
8,300-9,500 |
Nonagglomerating |
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3. Sub-bituminous C coal |
8,300-9,500 |
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IV. Lignitic |
1. Lignite A |
6,300-8,300 |
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2. Lignite В |
<6,300 |
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Source: ASTMD388 |
Feedstocks and Feedstock Characteristics 43 |
Figure 4-1. Proximate Analyses of Coals by Rank (Source: Baughman, 1978) |