By means of in situ diffuse reflectance FTIR, the IR spectra of 6 coals with different ranks were obtained from room temperature to 230 ℃. A new curve fitting method was used to recognize the different hydrogen ...By means of in situ diffuse reflectance FTIR, the IR spectra of 6 coals with different ranks were obtained from room temperature to 230 ℃. A new curve fitting method was used to recognize the different hydrogen bonds in the coals, and the influence of coal ranks on the distribution of hydrogen bonds(HBs) in the coals and their thermal stability were discussed. The results show that there is another new HB(around 2514 cm -1 ) between the -SH in mercaptans or thiophenols and the nitrogen in the pyridine like compounds in the coals, and the evidence for that was provided. The controversial band of the HB between hydroxyl and the nitrogen of the pyridine like compounds was determined in the range of 3028-2984 cm -1 , and the result is consistent with but more specific than that of Painter et al .. It was found that the stability of different HBs in the coals is influenced by both coal rank and temperature. For some HBs, the higher the coal rank, the higher the stability of them. Within the temperature range of our research, the stability of the HB between the hydroxyl and the π bond increases to some extent for some coals at temperatures higher than 110 or 140 ℃.展开更多
[ Objective l The study aimed to discuss the optimal conditions of extracting humic acids from brown coal using hydrogen peroxide （H202）. [ Method] Fulvic acid （FA） was prepared through oxidizing the brown coal fr...[ Objective l The study aimed to discuss the optimal conditions of extracting humic acids from brown coal using hydrogen peroxide （H202）. [ Method] Fulvic acid （FA） was prepared through oxidizing the brown coal from Qujing City, Yunnan Province using H202, and humic acids were extracted from the original brown coal and its residues respectively, then the dominate constituents of humic acids were obtained by using pH grading method, finally their chemical composition of humid acids was characterized by Fourier transform infrared spectrometry and func- tional group content analysis. [Result] The mass ratio of the brown coal and oxidant affected the yield of FA most obviously, followed by oxidization temperature and duration, while oxidant concentration had no obvious effect. The optimum conditions were determined as follows： coal-oxidant ratio was 1 ： 0.60, oxidization temperature was 45 ℃, oxidization duration was 210 min, and the concentration of hydrogen peroxide was 20%. Under the conditions, the yield of FA was up to 20.40%. Analysis of component properties indicated that the content of carboxyl and total acidic groups in FA improved obviously under the optimum conditions, and the content of active functional groups in OHA was higher than that of HA, while the domi- nate constituents of OHA needed higher pH during precipitation compared with those of HA. [ Conclusion] The research could provide a new method to prepare good humic acids using brown coal,展开更多
富油煤是集煤、油、气属性于一身的煤基油气资源,针对国内“相对富煤、缺油、少气”的能源禀赋,开发富油煤对缓解我国紧张的油气资源供应局势、实现煤炭的绿色开发和低碳利用具有重要的意义。以富油煤为主要关键词,通过CNKI和Web of Sci...富油煤是集煤、油、气属性于一身的煤基油气资源,针对国内“相对富煤、缺油、少气”的能源禀赋,开发富油煤对缓解我国紧张的油气资源供应局势、实现煤炭的绿色开发和低碳利用具有重要的意义。以富油煤为主要关键词,通过CNKI和Web of Science数据库检索自1985-2023年底已公开发表的学术论文和专利,统计分析富油煤的发展历程和主要研究内容,梳理了富油煤研究的热点方向与前沿领域,展望了未来发展趋势。研究发现:富油煤热解、赋存特征及沉积环境、孔隙和分子结构、焦油产率预测、微生物降解、资源潜力及开发利用是当前富油煤研究热点内容。富油煤含有热解可生成油气的富氢结构,如脂肪结构的侧链与桥键及缩合芳香核周缘的弱键结构;富油煤多形成于陆相沉积物供应稳定、气候温暖湿润、强还原条件下的沉积环境;孔隙结构影响富油煤的热解反应效率、焦油析出和油气运移,而分子结构(主要为脂肪族氢含量和富氢弱键)决定了富油煤的生油潜力;富油煤通过微生物的水解、发酵、产氢产乙酸和产甲烷4个阶段向油气转化。随着地质选区技术瓶颈突破及多学科交叉与融合,富油煤富油性评价指标与预测方法、富氢组分的来源与定量判识、原位开发围岩封闭性及其评价方法、微生物降解与热解联作技术将成为今后研究的热点方向。研究成果为厘清当前富油煤的研究方向和未来走势奠定了基础。展开更多
基金Supported by the National Natural Science Foundation of China(No.2 990 6 0 12)
文摘By means of in situ diffuse reflectance FTIR, the IR spectra of 6 coals with different ranks were obtained from room temperature to 230 ℃. A new curve fitting method was used to recognize the different hydrogen bonds in the coals, and the influence of coal ranks on the distribution of hydrogen bonds(HBs) in the coals and their thermal stability were discussed. The results show that there is another new HB(around 2514 cm -1 ) between the -SH in mercaptans or thiophenols and the nitrogen in the pyridine like compounds in the coals, and the evidence for that was provided. The controversial band of the HB between hydroxyl and the nitrogen of the pyridine like compounds was determined in the range of 3028-2984 cm -1 , and the result is consistent with but more specific than that of Painter et al .. It was found that the stability of different HBs in the coals is influenced by both coal rank and temperature. For some HBs, the higher the coal rank, the higher the stability of them. Within the temperature range of our research, the stability of the HB between the hydroxyl and the π bond increases to some extent for some coals at temperatures higher than 110 or 140 ℃.
基金Supported by Scientific Research Foundation of Educational Commission of Yunnan Province,China (08C0186)
文摘[ Objective l The study aimed to discuss the optimal conditions of extracting humic acids from brown coal using hydrogen peroxide （H202）. [ Method] Fulvic acid （FA） was prepared through oxidizing the brown coal from Qujing City, Yunnan Province using H202, and humic acids were extracted from the original brown coal and its residues respectively, then the dominate constituents of humic acids were obtained by using pH grading method, finally their chemical composition of humid acids was characterized by Fourier transform infrared spectrometry and func- tional group content analysis. [Result] The mass ratio of the brown coal and oxidant affected the yield of FA most obviously, followed by oxidization temperature and duration, while oxidant concentration had no obvious effect. The optimum conditions were determined as follows： coal-oxidant ratio was 1 ： 0.60, oxidization temperature was 45 ℃, oxidization duration was 210 min, and the concentration of hydrogen peroxide was 20%. Under the conditions, the yield of FA was up to 20.40%. Analysis of component properties indicated that the content of carboxyl and total acidic groups in FA improved obviously under the optimum conditions, and the content of active functional groups in OHA was higher than that of HA, while the domi- nate constituents of OHA needed higher pH during precipitation compared with those of HA. [ Conclusion] The research could provide a new method to prepare good humic acids using brown coal,
文摘富油煤是集煤、油、气属性于一身的煤基油气资源,针对国内“相对富煤、缺油、少气”的能源禀赋,开发富油煤对缓解我国紧张的油气资源供应局势、实现煤炭的绿色开发和低碳利用具有重要的意义。以富油煤为主要关键词,通过CNKI和Web of Science数据库检索自1985-2023年底已公开发表的学术论文和专利,统计分析富油煤的发展历程和主要研究内容,梳理了富油煤研究的热点方向与前沿领域,展望了未来发展趋势。研究发现:富油煤热解、赋存特征及沉积环境、孔隙和分子结构、焦油产率预测、微生物降解、资源潜力及开发利用是当前富油煤研究热点内容。富油煤含有热解可生成油气的富氢结构,如脂肪结构的侧链与桥键及缩合芳香核周缘的弱键结构;富油煤多形成于陆相沉积物供应稳定、气候温暖湿润、强还原条件下的沉积环境;孔隙结构影响富油煤的热解反应效率、焦油析出和油气运移,而分子结构(主要为脂肪族氢含量和富氢弱键)决定了富油煤的生油潜力;富油煤通过微生物的水解、发酵、产氢产乙酸和产甲烷4个阶段向油气转化。随着地质选区技术瓶颈突破及多学科交叉与融合,富油煤富油性评价指标与预测方法、富氢组分的来源与定量判识、原位开发围岩封闭性及其评价方法、微生物降解与热解联作技术将成为今后研究的热点方向。研究成果为厘清当前富油煤的研究方向和未来走势奠定了基础。
