Effects of oxygen on the structure and reactivity of char during steam gasification of Shengli brown coal

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• 作者：Jia-liang SUN ; Xu-jun CHEN ; Fang WANG ; Xiong-chao LIN ; Yong-gang WANG ; ^{wyg1960@126.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：brown coal ; gasification ; char structure ; char reactivity ; simulated entrained-flow reactor
• 刊名：Journal of Fuel Chemistry and Technology
• 出版年：2015
• 出版时间：July 2015
• 年：2015
• 卷：43
• 期：7
• 页码：769-778
• 全文大小：2909 K

文摘

The effects of oxygen on changes in char structure and reactivity during steam gasification of Shengli brown coal were examined. A stainless steel simulated entrained-flow reactor was employed to carry out gasification at 800 and 900°C in 8 atmospheres: pure N₂, 15%H₂O, 25%H₂O and 35%H₂O balanced with N₂; and 1%O₂, 15%H₂O+1%O₂, 25%H₂O+1%O₂ and 35%H₂O+1%O₂ balanced with N₂. The structure of chars was measured by Raman spectrum, and the intrinsic reactivity of chars with air was measured using a thermogravimetric analyzer (TGA) at low temperature (300°C). The results show that the effects of oxygen on char structure are different at high temperature (900°C) and low temperature (800°C) in brown coal steam gasification. The volatilization of alkali and alkaline earth metallic (AAEM) is strongly influenced by char structure. The presence of O₂ during steam gasification has a similar effect on the volatilization of Na to the evolution of structure at different temperatures. Experimental data provided evidence that a mixed H₂O/O₂ atmosphere could promote a decrease in subsequent char reactivity in air at 300°C, and that char reactivity could correlate well with the band area ratio, I_(GR+VL+VR)/I_D.