| Budget Amount *help |
¥33,500,000 (Direct Cost: ¥33,500,000)
Fiscal Year 2002: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 2001: ¥7,700,000 (Direct Cost: ¥7,700,000)
Fiscal Year 2000: ¥9,600,000 (Direct Cost: ¥9,600,000)
Fiscal Year 1999: ¥10,800,000 (Direct Cost: ¥10,800,000)
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| Research Abstract |
In order to improve the liberation of mineral inclusions and the efficiency of grinding energy utilization, pretreatment of coal by methanol was explored. Fourteen kinds of coals were treated with methanol at room temperature for the desired time. After methanol treatment, all the coals tended to be easily ground. The compressive strength of the treated coal particle was reduced to about a half of that of parent coal. The grindability of the treated coal was quite higher than that of raw coal. For example, the cumulative weight percent of the particles under 0.150 mm were increased from 20.8 to 50.3%, from 44.4 to 87%, from 32.6 to 42.6%, from 27 to 48.8% and from 2.6 to 6.4% after treatment, respectively, for Yang-song coal, Ebenezre coal, Datong coal, Newlands coal and Ramagundum coal. The effectiveness of the methanol pretreatment on the grindability depended on coal type.
SEM obseavation revealed that many cracks were formed in coal particle by the pretreatment. CC-SEM analysis revealed the possibility of selective mineral reduction by the benification with pretreatment in methanol. A centrifugal separation was conducted for ground coal sample. Organic matter recovery and mineral matter reduction were improved by the pretreatment. For example, in the case of Yang-song coal, the organic matter recovery is 78, 59 and 32% for untreated coal and 92, 80 and 53% for treated coal at ash reductions of 85, 90 and 95%, respectively.
In order to reduce the emission of organic sulfur, calcium compound is loaded to the pretreated coal. Reactions of Ca compounds with coal char were examined at temperatures up to 1600℃. CaO started to react with coal char at a temperature as low as 950℃ and exerted a strong catalytic effect on the graphitization of coal char, mainly forming the graphitic carbon at 1600℃.
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