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- Title
CHARACTERIZATION OF ASH CONTENT, COKING TENDENCIES AND EVALUATION OF PHYSICOCHEMICAL PROPERTIES OF OKOBO COALS.
- Authors
Oni, Samuel Oluwaseun; Olugbenga, Ehinola A.; Chidimma, Gideon Nwafor
- Abstract
The mineral content of coal affects the type of ash that will be produced on combustion. Despite the same volatile matter content, the Okobo 1 FSI is 3.7 with ash content of 16.7 while Okobo 2 FSI is 6.8 with an ash content of 8.2. Ash fusion is 1,400°C, various ash slagging index indices such as silica ratio (Sr), basic to acidic oxide (B/A), and sulphur index (Rs) for Okobo coal are: 85, 0.13, 0.23 respectively implying low slagging characteristics. The Gross Calorific Value GCV of Okobo 1 and Okobo 2 are 20.88 MJ/Kg (8796 Btu/lb) and 19.86MJ/Kg (8536 Btu/lb) respectively congruous with lowest grade of subbituminous coal termed the "sub-bituminous C grade" according to ASTM classification. The fixed carbon values are 59.5% (Okobo 1) and 59.7% (Okobo 2) while the moisture content of Okobo 1 is 12.8 and Okobo2 is 23.1, an indication of possible coking with beneficiation. The total alkali of the coal (0.63%) is less than 2%, Silica (SiO2) is 62.3%, potassium as K2O, % is 0.53 Fe2O3 is 7.96%. The phosphorus oxide content of Okobo coal is 0.07, < 0.1% stipulated while the phosphorus content is 0.011. The Ignitability Index for Okobo1 is 42.5 and Okobo2 is 33, fuel ratio 1.1, Methane content VCH4 of Okobo1 and Okobo2 are respectively 10.89 (m3/tonne) and 11.7(m3/tonne) corresponding to good ignitability, good fuel reactivity and thus good efficiency and within limits of safe methane emission that may not produce mine fires. CO2 Emission factor of Okobo1 at 247.8 Ibs/MMBtu and Okobo2= 239.1 Ibs/MMBtu within range prescribed as safe by Clean Air Act of 1990.
- Subjects
FLY ash; COAL combustion; MINERAL content of coal
- Publication
Petroleum & Coal, 2017, Vol 59, Issue 3, p397
- ISSN
1335-3055
- Publication type
Article