Effect of Operational Variables on the Hydrogasification of Inner Mongolian Lignite Semicoke

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• 作者：Xiaokuo Ding ; Yongfa Zhang ; Tiankai Zhang ; Jian Tang ; Ying Xu ; Jing Zhang
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：August 15, 2013
• 年：2013
• 卷：27
• 期：8
• 页码：4589-4597
• 全文大小：496K
• 年卷期：v.27,no.8(August 15, 2013)
• ISSN：1520-5029

文摘

Hydrogasification of Inner Mongolian lignite semicoke was investigated at varying operational conditions: grain size of 0.15鈥?.7 mm, hydrogen flow rate of 300鈥?500 mL/min, temperature of 700鈥?00 掳C, pressure of 0.1鈥?.0 MPa, and heating rate of 10鈥?0 掳C/min, using a self-developed high-temperature and high-pressure fixed-bed reactor with a design parameter of 1000 掳C and 12 MPa. The reaction characteristics and mechanism of semicoke hydrogasification were discussed. The results showed that, at a grain size of semicoke of <0.25 mm and a hydrogen flow rate of >1200 mL/min, the effects of internal and external diffusion resistances were basically eliminated; the increase of the pressure or heating rate exerted a positive influence on the hydrogasification of semicoke. The optimum reaction conditions were as follows: grain size of 0.25鈥?.35 mm, hydrogen flow rate of 1200 mL/min, temperature of 800 掳C, and pressure of 3.0鈥?.0 MPa. During hydrogasification, the fracture of alkyl side chains, hydrogenation/methanation of carbon (e.g., C + 2H₂ = CH₄), and hydrogenation of oxygen-containing structures were accelerated. Three stages occurred during hydrogasification of Inner Mongolian lignite semicoke: hydropyrolysis stage, rapid hydrogasification stage, and slow hydrogasification stage. Moreover, the reaction characteristics of each stage were quite different because of distinct carbon structures.