• Journal of Energy Engineering
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• v.21 no.4
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• pp.325-338
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• 2012

Currently, there are the technologically urgent needs of fabricating the hyper coal (HC) based on the approach to extracting mainly effective organics from low rank coals (LRCs), because some industrial countries pursue global sustainability dealing with hot issues such as local energy supply security as well as global warming. In this study, as of the fabrication of clean HCs via LRCs upgrading, we comprehensively review the R&D status of two solvent extraction technologies, namely, Ohm heating (OH) and microwave irradiation (MI) extraction processes on the basis of the performance indicator such as a HC extraction yield.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.213-222
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• 2011

To check adaptability of low ash coal(hyper coal) to chemical looping combustion, reaction characteristics of two coals (Roto and Hyper coal) with two oxygen carriers (NiO/bentonite, OCN703-1100) have been investigated in a thermogravimetric analyzer. Hyper coal represented low combustion rate and high ignition temperature, high volatile content and high devolatilization rate, and therefore, showed worse oxygen transfer during successive 10 cycle reduction-oxidation test than Roto coal. Finally we selected Roto coal as the candidate coal for chemical looping combustion. For Roto coal, OCN703-1100 particle showed better oxygen transfer than NiO/bentonite particle. During 10 cycle reduction oxidation test, change of the extent of oxidation (Wo) was negligible and we could conclude that both oxygen carriers have sufficient regeneration ability.