Change in Catalytic Activity of Potassium during CO2 Gasification of Char
Change in Catalytic Activity of Potassium during CO2 Gasification of Char
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DOI：
10.1021/acs.energyfuels.9b03630
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发表时间：
2020-01-01
期刊：
影响因子：
5.3
通讯作者：
Hayashi, Jun-ichiro
中科院分区：
文献类型：
--
作者：
Halim, Nurulhuda;Tajima, Akira;Hayashi, Jun-ichiro
研究了钾(K)催化的褐煤炭的CO2气化，特别关注了在800-900℃下炭转化(X)过程中催化剂活性的变化。以印度尼西亚褐煤为原料，通过完全去除固有金属和矿物、离子交换钾负载和热解制备炭样。K的催化活性（K′（cat））定义为气化炭每保留一定量K的催化气化速率（在除去非催化气化速率和炭总质量释放速率中挥发K的速率后）。k′（cat）在其范围内增加了5-20倍，达到0.98-0.99，这取决于char （m(cat,0)）中的初始k浓度（范围为0.16-1.4 wt %-daf）。k′（cat）的显著增加不是由于炭的固有反应性的变化，而是由于其多孔性的变化，即保留k催化剂的孔的大小和体积的变化。当X < 0.4时，K催化剂的整个部分被限制在微孔(宽度为
Potassium (K)-catalyzed CO2 gasification of lignite char was studied with a particular focus on the change in catalyst activity with the char conversion (X) at 800-900 degrees C. Char samples were prepared from an Indonesian lignite by a sequence of complete removal of inherent metallic species and mineral matter, K-loading by ion-exchange, and pyrolysis. The catalytic activity of K (k'(cat)) was defined as the rate of catalytic gasification (after elimination of the rate of non-catalytic gasification and that of K volatilization from total mass release rate from char) per amount of K retained by the gasifying char. k'(cat) increased by a factor of 5-20 with X over its range up to 0.98-0.99, depending on the initial K concentration in the char (m(cat,0))( ranging 0.16-1.4 wt %-daf.. Such significant increase in k'(cat) was due to the change in not the intrinsic reactivity of char but its porous nature, that is, the size and volume of pores that retained the K catalyst. At X < 0.4, the entire portion of the K catalyst was confined in micropores (width