Improving the Environmental and Economic Viability of U.S. Oil Shale via Waste-to-Byproduct Conversion of Semicoke to Sorbents
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- 作者：Ami Vyas ; Junjie Xue ; Jillian L. Goldfarb
- 刊名：Energy & Fuels
- 出版年：2016
- 出版时间：January 21, 2016
- 年：2016
- 卷：30
- 期：1
- 页码：188-195
- 全文大小：595K
- ISSN：1520-5029
文摘
This investigation demonstrates the feasibility of mitigating the economic and environmental burdens associated with commercialization of oil shale by converting its primary solid waste, semicoke, to an adsorbent material. U.S. White River Mine oil shale was pyrolyzed at 600 °C to produce a semicoke; its activation energy of pyrolysis was calculated using the distributed activation energy model to be 206.9 kJ/mol, similar to other domestic oil shales. This simulated semicoke was chemically activated using HCl, KOH, and a double-activation procedure of either HCl followed by KOH or vice versa. The acid-activation step was considerably more effective in developing the surface area and porous network of the semicoke sorbents, as well as removing carbonate minerals, than KOH. The activation energies of oxidation of the raw, pyrolyzed, and activated samples ranged from 100.5 kJ/mol (raw) to 189.0 kJ/mol (semicoke), with the activated samples between these values. Of the activated samples, HCl + KOH had the lowest overall average oxidation-activation energy, 104.4 kJ/mol, and also had the highest derivative thermogravimetric curve peak, indicating high reactivity. The BET surface area of this sample was 74.3 m2/g. However, in the interest of reducing process steps, the single activation using HCl is likely a more efficient option for byproduct conversion, yielding a BET surface area of 51.7 m2/g, which is considerably higher than that of Class F coal fly ash, at ～5m2/g, a waste material that is commonly employed as a sorbent.