H2O2 oxidation of Xianfeng lignite and its thermal extraction residue
-
摘要: 利用1-甲基萘(1-MN)对先锋褐煤进行热溶,并在温和条件下分别对原煤及其热溶残煤进行过氧化氢氧化。结合元素分析和FT-IR对各级产物进行结构表征,用GC/MS对氧化反应水溶性产物的甲酯化衍生物进行分析。结果表明,先锋褐煤在1-MN中的热溶率较低,320 ℃下热溶残煤(TR)的收率为81.01%,该煤主要以共价键交联的大分子结构为主,非共价键缔合的小分子含量较低,并以脂肪结构为主,含一定量的羰基以及少量的羟基和芳香结构。原煤和热溶残煤氧化水溶性产物中α,ω-二羧基烷酸含量较高,同时还发现,相当含量的芳香酸及三元羧酸存在,其中,α,ω-二羧基烷酸主要以丙二酸和丁二酸为主;原煤中可溶小分子易被氧化并生成较复杂的产物。与原煤相比,热溶残煤结构更为规整,氧化主要以共价键交联的大分子结构的氧化解聚为主,氧解率较低,水溶性氧解产物也较简单,种类较少,据此推测先锋褐煤的桥键主要以为-CH2-和-CH2-CH2-为主。Abstract: Thermal extraction of Xianfeng lignite (XL) with 1-methylnaphthalene (1-MN) was carried out at 320 ℃, and the H2O2 oxidation of the thermal extraction residue (TR) was compared with that of XL raw coal. The thermal extract (TE), TR and the oxidized residues were characterized by element analysis and FT-IR. The aqueous products from oxidation reaction were esterified and analyzed by GC/MS. The result shows that the yield of TR from XL in 1-MN is 81.01%. It indicates that XL is mainly composed of macromolecular structure cross-linked by covalent bond, with less low molecular compounds associated by non-covalent bond interactions. The TE is mainly composed of aliphatic hydrocarbons, carboxylic acid esters with less aromatic structures and hydroxyl group. GC/MS results suggest that the water-soluble products contained highest content of α, ω-dicarboxylic acids, especially malonic acid and succinic acid, with much amount of benzoic acid and tricarboxylic acids. The low molecular weight compounds associated in the macromolecular structure of raw coal can be easily oxidized under the conditions and more species of oxidation products are obtained. Compared with the structure of raw coal, the structure of TR is more regular. The oxidation of TR mainly occurs on the macromolecular structure cross-linked by covalent bond, resulting in the higher yield of oxidized residue and less species of water-soluble products from TR. The high yields of malonic acid and succinic acid in the water-soluble products suggest that -CH2-and -CH2-CH2-are the main cross-linking bonds in the macromolecular network structure of XL.
-
Key words:
- lignite /
- thermal extraction /
- oxidation /
- GC/MS
-
YOSHIDA T, LI C, TAKANOHASHI T, MATSUMURA A, SATO S, SAITO I. Effect of extraction condition on "hypercoal" production (2): Effect of polar solvents under hot filtration[J]. Fuel Process Technol, 2004, 86(1): 61-72. MIURA K, NAKAGAWA H, ASHIDA R, IHARA T. Production of clean fuels by solvent skimming of coal at around 350℃[J]. Fuel, 2004, 83(6): 733-738. ASHIDA R, NAKAGAWA K, OGA M, NAKAGAWA H, MIURA K. Fractionation of coal by use of high temperature solvent extraction technique and characterization of the fractions[J]. Fuel, 2008, 87(4/5): 576-582. TAKANOHASHI T, SHISHIDO T, KAWASHIMA H, SAITO I. Characterisation of Hypercoals from coals of various ranks[J]. Fuel, 2008, 87(4/5): 592-598. MIURA K, SHIMADA M, MAE K, SOCK H Y. Extraction of coal below 350℃ in flowing non-polar solvent[J]. Fuel, 2001, 80(11): 1573-1582. ASHIDA R, MORIMOTO M, MAKINO Y, UMEMOTO S, NAKAGAWA H, MIURA K, SAITO K, KATO K. Fractionation of brown coal by sequential high temperature solvent extraction[J]. Fuel, 2009, 88(8): 1485-1490. 王知彩, 李良, 水恒福, 雷智平, 任世彪, 康士刚, 潘春秀. 先锋褐煤热溶及热溶物红外光谱表征[J]. 燃料化学学报, 2011, 39(6): 401-406. (WANG Zhi-cai, LI Liang, SHUI Heng-fu, LEI Zhi-ping, REN Shi-biao, KANG Shi-gang, PAN Chun-xiu. High temperature thermal extraction of Xianfeng lignite and FT-IR characterization of its extracts and residues[J]. Journal of Fuel Chemistry and Technology, 2011, 39(6): 401-406.) 常鸿雁, 韩文煜, 张德祥, 高晋生. 煤直接液化中油煤浆热溶产物的变化[J]. 煤炭学报, 2005, 30(1): 90-94. (CHANG Hong-yan, HAN Wen-yu, ZHANG De-xiang, GAO Jin-sheng. Study on thermally dissolved product changes of coal-oilslurry during direct coal liquefaction[J]. Journal of China Coal Society, 2005, 30(1): 90-94. SHUI H F, ZHOU Y, LI H P, WANG Z C, LEI Z P, REN S B, PAN C X, WANG W W. Thermal dissolution of Shenfu coal in different solvents[J]. Fuel, 2013, 108: 385-390. 刘振学, 魏贤勇, 刘泽常. 煤的氧化反应研究进展[J]. 煤炭转化, 2000, 23(4): 7-10. (LIU Zhen-xue, WEI Xian-yong, LIU Ze-chang. Advance of coal oxidizing reaction studies[J]. Coal Conversion, 2000, 23(4): 7-10. MIURA K, MAE K, OKUTSU H, MIZUTANI N. Production of organic acids in high yields from brown coal through the liquid phase oxidation with H2O2 at low temperature[J]. Am Chem Soc Div Fuel Chem, 1996, 41(2): 734-738. MIURA K, MAE K, OKUTSU H, MIZUTANI N. New oxidative degradation method for producing fatty acids in high yields and high selectivity from low-rank coals[J]. Energy Fuels, 1996, 10(6): 1196-1201. MAE K, MAKI T, ARAKI J, MIURA K. Extraction of low-rank coals oxidized with hydrogen peroxide in conventionally used solvents at room temperature[J]. Energy Fuels, 1997, 11(4): 825-831. 冯波, 其鲁, 张敬华, 孙小嫚, 杨凡. 弱氧化环境下褐煤氧化产物的定性分析[J]. 冶金分析, 2009, 29(1): 21-24. (FENG Bo, QI Lu, ZHANG Jin-hua, SUN Xiao-man, YANG Fan. Qualitiative analysis of brown coal oxidation products in mild oxidizing atmosphere[J]. Metallurgical Analysis, 2009, 29(1): 21-24. 陈虹, 宗志敏, 张佳伟, 黄斌, 韩勇, 王桃霞, 魏贤勇. 温和条件下黑岱沟萃余煤的双氧水氧化产物分析[J]. 中国矿业大学学报, 2008, 37(3): 347-353. (CHEN Hong, ZONG Zhi-min, ZHANG Jia-wei, HUANG Bin, HAN Yong, WANG Tao-xia, WEI Xian-yong. Analysis of products from the oxidation of Heidaigou coal residue with H2O2 aqueous under mild condition[J]. Journal of China University of Mining & Technology, 2008, 37(3): 347-353.) LIU Z, LIU Z, ZONG Z, WEI X, WANG J, LEE C W. GC/MS analysis of water-soluble products from the mild oxidation of Longkou brown coal with H2O2[J]. Energy Fuels, 2003, 17(2): 424-426. PAN C, WEI X, SHUI H, WANG Z, GAO J, WEI C, CAO X, ZONG Z. Investigation of the macromolecular network structure of Xianfeng lignite by a new two-step depolymerization[J]. Fuel, 2013, 109: 49-53. ALVAREZ R, CLEMENTE C, GOMEZ-LIMON D. The influence of nitric acid oxidation of low rank coal and its impact on coal structure[J]. 2003, Fuel, 82(15/17): 2007-2015. DENO N C, GREIGGER B A, STROUND S G. New method for elucidating the structures of coal[J]. Fuel, 1978, 57(8): 455-459. HUANG Y, ZONG Z, YAO Z, ZHENG Y, MOU J, LIU G, CAO J, DING M, CAI K, WANG F, ZHAO W, XIA Z, WU L, WEI X. Ruthenium ion-catalyzed oxidation of Shenfucoal and its residues[J]. Energy Fuels, 2008, 22(3): 1799-1806. YAO Z, WEI X, LV J, LIU F, HUANG Y, XU J, CHEN F, HUANG Y, LI Y, LU Y, ZONG Z. Oxidation of Shenfu coal with RuO4 and NaOCl[J]. Energy Fuels, 2010, 24(3): 1801-1808. VERHEYEN T V, JOHNS R B. Analysis of peroxytrifluoroacetic acid oxidation products from Victorian brown coal[J]. Anal Chem, 1983, 55(9): 1564-1568.
点击查看大图
计量
- 文章访问数: 1363
- HTML全文浏览量: 32
- PDF下载量: 730
- 被引次数: 0