Sequential conversion of lignite in alkaline water by oxidative degradation, dissolution and catalytic gasification
Sequential conversion of lignite in alkaline water by oxidative degradation, dissolution and catalytic gasification
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DOI：
10.1016/j.fuel.2020.118329
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发表时间：
2020-10
期刊：
影响因子：
7.4
通讯作者：
Tianlong Liu;Shusaku Asano;Shinji Kudo;J. Hayashi
中科院分区：
文献类型：
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作者：
Tianlong Liu;Shusaku Asano;Shinji Kudo;J. Hayashi
研究了褐煤在碱性水溶液中的降解、溶解和催化水热气化过程。维多利亚褐煤在250 °C的NaOH水溶液中进行水热处理（HT），然后在100 °C下用加压O2氧化。顺序的HT和氧化溶解了95%的褐煤的质量/碳的基础上。将所得溶液通过CHTG在流动反应器中在350 °C下使用钌/活性炭催化剂（钌负载量; 16重量%）进一步转化10小时。初始碳转化为气体的转化率高达98%，同时产生CH 4、CO2和H2。由于焦炭沉积在催化剂上，转化率逐渐降低，但在8-10 h时接近稳定在83%左右。溶解的褐煤由分子量高达5，000的化合物组成。较重的部分（分子量> 1，000）负责焦炭的形成和积累，导致催化剂失活。
We have demonstrated a sequence of degradation, dissolution and catalytic hydrothermal gasification (CHTG) of lignite in alkaline water. A Victorian lignite was subjected to hydrothermal treatment (HT) in an aqueous solution of NaOH at 250 °C, and then oxidation with pressurized O2at 100 °C. The sequential HT and oxidation solubilized a 95% portion of the lignite on mass/carbon bases. The resulting solution was further converted by CHTG in a flow reactor at 350 °C for 10 h, employing a ruthenium/activated-charcoal catalyst (ruthenium loading; 16 wt%). The initial carbon conversion to gas was as high as 98% while CH4, CO2and H2were produced. The conversion gradually decreased due to coke deposition over the catalyst but was near steady around 83% at 8–10 h. The solubilized lignite consisted of compounds with molecular mass up to 5,000. The heavier portion (molecular mass > 1,000) was responsible for the coke formation and accumulation that caused the catalyst deactivation.