Graphite and Graphite Oxide: New Models to Analyze the Calcium Catalytic Effect on Steam Gasification of Lignite and Char
Graphite and Graphite Oxide: New Models to Analyze the Calcium Catalytic Effect on Steam Gasification of Lignite and Char
复制标题
石墨和氧化石墨：分析钙对褐煤和焦蒸汽气化作用的新模型
DOI：
10.1021/acs.energyfuels.9b02443
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发表时间：
2019
期刊：
影响因子：
5.3
通讯作者：
Li Na
中科院分区：
文献类型：
--
作者：
Ban Yanpeng;Liu Quansheng;Zhou Huacong;He Runxia;Zhi Keduan;Li Na
首次以氧化石墨（GO）和石墨（G）作为胜利褐煤（SL）和半焦（SL+-T）的模型，研究了它们的气化反应性。SL+、SL+-T、G、GO和相应的添加Ca的样品的水蒸气气化性能在配备有下游GC系统并与下游GC系统连接的固定床反应器中进行评价。采用傅里叶变换红外光谱、X射线衍射、拉曼光谱、X射线光电子能谱和13 C核磁共振谱对样品进行了表征。结果表明，钙对SL+和GO的水蒸气气化有明显的催化作用，但对高温半焦和G.采用液相氧化法制备GO后，添加Ca的氧化半焦在低温下的水蒸气气化速率表现出更高的反应活性，与添加Ca的GO的气化行为相似。表征结果表明，SL的含氧官能团与GO相似。通过比较氧化半焦和GO中钙与半焦和G中钙的催化效果，进一步证明了含氧官能团是钙催化煤气化的关键结构。这些结果表明，GO是类似的SL不仅在其氧结构，而且在其蒸汽气化反应性。因此，GO是褐煤的优良模型。该研究提供了一种新的褐煤建模方法，比已报道的褐煤模型具有更准确的结构，适合于精确研究褐煤的结构演化以及钙在蒸汽气化中的催化机制。
Graphite oxide (GO) and graphite (G) were used as Shengli lignite (SL) and char (SL+-T) models to study gasification reactivity for the first time. The steam gasification performance of SL+, SL+-T, G, GO and the corresponding Ca-added samples was evaluated in a fixed bed reactor equipped and linked with a downstream GC system. The samples were comprehensively characterized by Fourier transform infrared, XRD, Raman, X-ray photoelectron spectroscopy, and13C NMR. Results show that calcium exerted a significant catalytic effect on the steam gasification of SL+and GO but had a limited impact on high-temperature char and G. Once the char was oxidized using a similar liquid oxidation method to prepare GO, the steam gasification rate of the oxidized Ca-added char presented higher reactivity at low temperature, which was similar to the gasification behavior of GO with calcium addition. Characterization results show that the oxygen-containing functional group of SL is similar to GO. By comparing the catalytic effect of calcium of oxidized char and GO with that of char and G, it was further demonstrated that the oxygen-containing functional group was the key structure for Ca-catalyzed coal gasification. These results suggest that GO is similar to SL not only in terms of its oxygen structure but also in its steam gasification reactivity. Thus, GO is an excellent model of lignite. This study provides a new lignite modeling approach with a more accurate structure than reported lignite models and is suitable for precise investigations of the structural evolution of lignite as well as the catalytic mechanism of calcium in steam gasification.