Coking Potential

Coking Potentials and Calorific Value Coking potential is investigated at preliminary level by proximate analysis, which involves the determination of chemical parameters such as moisture, volatile matter, ash and fixed carbon content. These characteristic values are used in assessing the degree of coalification (rank) of a coal as well as its application in the area of coke making and energy/power generation.

Moisture content: The moisture content is a measure of the amount of water in the fuel. In solid fuels, moisture can exist in two forms: as free water within the pores and interstices of the fuel, and as bound water which is part of the chemical structure of the material (Borman and Ragland, 1998). The moisture content (water

High moisture content is disadvantageous because it decreases system capacity and increases operational cost (Jauro, 2007). A matured coal for good coke making should have less than 5 % moisture content (Adeleke et al., 2007). It is an important parameter in commercial transaction and in control of blast furnace operation. Blast furnace operators generally require a practically dry coke. The moisture content of coke depends on the quenching process: wet quenching uses water while dry cooling uses cold air. The latter method improves the strength indices (M40 & M10) of coke to some extent and is widely asserted that it is practice in Japan. The moisture makes the small particles adhere to the large lump of cokes, which may falsify the results of sieve analysis and essentially the M10 index. Moisture content is one among the many variables affecting the bulk density of coal blend and thus controlling the coke quality and yield. Increase in moisture reduces coal grindability, coking pressure and

The high ash content is also an indication of low degree of coalification and hence immaturity of the coal (Onoduku, 2014). According to Lin et al. (2011), original coal ashes contain various kinds of minerals; coexist as crystal and non-crystal minerals at different temperatures. The agglomeration of ash may be influenced by parameters such as the chemical composition, particle size, size distribution, bed temperature, atmospheric condition (Haykiri-Acma and Yaman, 2013) and the content level; which in turn affects the operation of blast furnace and cupola. Industrial experience indicates that a 1 weight percent increase of ash in the coke reduces metal production by 2 or 3 weight percent (Price et al., 1997). The disposal of ash is also a big problem which increases the cost of operation. And according to Jauro et al. (2008), coal ash emanating from the combustion may pose a potential environmental threat on disposal. Ash content of less than 10 % is recommended for a good coking coal (Akpabio et al., 2008). And the ash content of these coal samples is satisfactorily within the acceptable range (Appendix