不同带电情况下的噻吩硫热解机理计算
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摘要
为计算不同带电情况下煤中噻吩硫的热解机理,选用2种合理的反应物分子模型,改变分子模型携带电荷及自旋多重度,分别计算不同带电情况下煤中噻吩硫的热解。根据密度泛函理论,使用Gaussian09软件,研究煤中噻吩硫的热解机理。在B3LYP水平上采用6-31g(d)基组进行结构优化,准确找到每一步反应的过渡态;将计算结果与文献中实验结果进行对比,根据反应过程中的能量变化,分析当环境的还原性和氧化性不同时,带电情况对噻吩硫热解的影响。结果表明:反应物A经过3个过渡态,反应物B经过4个过渡态,均生成HCCH(C_2H_2)和HCCS;不带电荷状态下,初始阶段的反应更容易发生,即反应物A更容易发生碳碳键的断裂,反应物B更容易形成第二个过渡态前的中间体;带负电荷状态有利于反应最后生成HCCH(C_2H_2)和HCCS,反应能垒低而且热解产物更稳定。
In order to calculate the pyrolysis mechanism of thiophene sulfur under different electrification conditions, two reasonable molecular models of reactants were chosen and charges and spin multiplicities were changed to respectively calculate pyrolysis of thiophene in coal under different electrification conditions. According to density function theory, this paper uses Guassian09 software to study the pyrolysis mechanism. By using 6-31 g(d) basis set for structure optimization at B3 LYP level, it has correctly find out transient state of each step. Then it makes comparison between the calculation result and experimental results in documents. According to energy change in the process of reaction, it analyzes influence of electrification on pyrolysis of thiophene sulfur as reducibility and oxidability of the environment is different. The research result indicates that the reactant A has passes three transient states and the reactant B has passed four transient states. Both of A and B generate HCCH(C_2H_2) and HCCS. In the state of carrying no charge, reaction in the initial phase is liable to happen, which means the reactant A is liable to happen breakage of carbon-carbon bond while the reactant B is liable to form the intermediate before the second transient state. Negative charge is advantageous to generate HCCH(C_2H_2) and HCCS in the last reaction stage, and reaction energy barrier is low and product of pyrolysis is more stable.
In order to calculate the pyrolysis mechanism of thiophene sulfur under different electrification conditions, two reasonable molecular models of reactants were chosen and charges and spin multiplicities were changed to respectively calculate pyrolysis of thiophene in coal under different electrification conditions. According to density function theory, this paper uses Guassian09 software to study the pyrolysis mechanism. By using 6-31 g(d) basis set for structure optimization at B3 LYP level, it has correctly find out transient state of each step. Then it makes comparison between the calculation result and experimental results in documents. According to energy change in the process of reaction, it analyzes influence of electrification on pyrolysis of thiophene sulfur as reducibility and oxidability of the environment is different. The research result indicates that the reactant A has passes three transient states and the reactant B has passed four transient states. Both of A and B generate HCCH(C_2H_2) and HCCS. In the state of carrying no charge, reaction in the initial phase is liable to happen, which means the reactant A is liable to happen breakage of carbon-carbon bond while the reactant B is liable to form the intermediate before the second transient state. Negative charge is advantageous to generate HCCH(C_2H_2) and HCCS in the last reaction stage, and reaction energy barrier is low and product of pyrolysis is more stable.
引文
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[18] 陈萍,顾明言,林郁郁,等. 含酮基团对煤焦异相还原NO的影响 [J]. 燃料化学学报, 2018, 46(5): 521-528. CHEN Ping,GU Mingyan,LIN Yuyu,et al. Effect of ketone group on heterogeneous reduction of NO by char[J]. Journal of Fuel Chemistry and Technology,2018, 46(5): 521-528.
[19] SAMOKHVALOV A. Heterogeneous photocatalytic reactions of sulfur aromatic compounds [J]. Chemphyschem, 2011, 12(16): 2870-2885.
[20] 谢丽丽. 模型化合物及煤热解过程中硫释放行为的研究 [D]. 呼和浩特:内蒙古大学, 2014.
[21] 么秋香. 渭北高硫煤中有机硫赋存状态及热解迁移规律研究 [D]. 西安:西安科技大学, 2015.
[22] GUO H,WANG X,LIU F,et al. Sulfur release and its transformation behavior of sulfur-containing model compounds during pyrolysis under CO2 atmosphere [J]. Fuel, 2017, 206: 716-723.
[23] GU Y,YPERMAN J,REGGERS G,et al. Characterisation of volatile organic sulphur compounds release during coal pyrolysis in inert, hydrogen and CO2 atmosphere [J]. Fuel, 2016, 184: 304-313.
[2] 苗强. 燃煤脱硫技术研究现状及发展趋势[J]. 洁净煤技术, 2015,21(2): 59-63. MIAO Qiang. Research status and progress of steam coal desulfurization technologies[J]. Clean Coal Technology, 2015,21(2): 59-63.
[3] 赵毅,王涵,徐梦楠,等.燃煤烟气脱硫脱硝脱汞研究文献计量分析[J]. 热力发电,2018,47(6):8-15. ZHAO Yi,WANG Han,XU Mengnan,et al.Biliometric analysis of research papers on the removal of sulfur oxides,nitric oxide and mercury from coal-fired flue gas[J]. Thermal Power Generation,2018,47(6):8-15.
[4] 王炫,孟东栋,杨涛,等. 制碱白泥应用于燃煤电厂湿法烟气脱硫过程的反应特性 [J]. 广东电力, 2018, 31(5): 21-27. WANG Xuan,MENG Dongdong,YANG Tao,et al.Reaction characteristic of soda residue used in WFGD in coal-fired power plants[J]. Guangdong Electric Power,2018, 31(5): 21-27.
[5] 贾鑫,王勤辉,陈一凡,等.Fe2O3对小龙潭褐煤热解过程中硫迁移和转化特性的影响[J]. 热力发电,2018,47(12):60-65. JIA Xin,WANG Qinhui,CHEN Yifan,et al.Effect of Fe2O3 on transformation and migration of sulfur in Xiaolongtan lignite during pyrolysis[J]. Thermal Power Generation,2018,47(12):60-65.
[6] 张成. 煤中汞与矿物相关特性及燃烧前汞/硫脱除的实验及机理研究 [D]. 武汉:华中科技大学, 2009.
[7] 杜传梅. 煤中有机硫脱除机理的密度泛函研究 [D]. 淮南:安徽理工大学, 2014.
[8] GRYGLEWICZ G, JASIE?KO S. Sulfur groups in the cokes obtained from coals of different ranks [J]. Fuel Processing Technology, 1988, 19(1): 51-59.
[9] CALKINS W H. Investigation of organic sulfur-containing structures in coal by flash pyrolysis experiments [J]. Energy & Fuels, 1987, 1(1): 59-64.
[10] 高正阳,赵霖,杨朋飞.褐煤吸附水分子三聚体机理研究[J]. 热力发电,2018, 47 (9):76-83. GAO Zhengyang,ZHAO Lin,YANG Pengfei.Mechanism of water molecules trimer adsorption by lignite[J]. Thermal Power Generation,2018,47 (9):76-83.
[11] 康志忠,苏逸峰,高满达,等.准东煤烟气中Na2SO4形成的量子化学研究[J]. 热力发电,2018, 47 (9):56-62. KANG Zhizhong,SU Yifeng,GAO Manda,et al.Quantum chemical study on formation paths of Na2SO4 in flue gas of Zhundong coal[J]. Thermal Power Generation,2018,47(9):56-62.
[12] ZHANG M,DU C,MIN F,et al. Quantum chemistry investigation on influence regularity of the external energy fields to the organic sulfur structural characteristics in coal[J]. Journal of China Coal Society, 2014, 39(8): 1478-1484.
[13] DU C,ZHANG M,MIN F,et al. Vibrational and quantum chemical investigations of 4,6-dimethyldibenzothiophene[J]. International Journal of Oil Gas and Coal Technology, 2014, 7(3): 322-334.
[14] 王寒露,周臻,陈华锴. H2O2/[Hnmp]HCOO氧化苯并噻吩类硫化物的量子化学研究[J]. 新能源进展, 2016,4(6): 492-498. WANG Hanlu,ZHOU Zhen,CHEN Huakai. Quantum chemical study on H2O2/[Hnmp]HCOO ionic liquid in the oxidative desulfurization of sulfides[J]. Advances In New and Renewable Energy,2016,4(6): 492-498.
[15] 庞先勇,吕存琴,吕永康. 煤脱硫过程的量子化学研究[J]. 煤炭转化, 2006,29(4): 17-20. PANG Xianyong,Lü Cunqin,Lü Yongkang. Quantum chemistry study on desulfuration process of coal[J]. Coal Conversion, 2006,29(4): 17-20.
[16] LING L X,ZHANG R G,WANG B J,et al. DFT study on the sulfur migration during benzenethiol pyrolysis in coal[J]. Journal of Molecular Structure-Theochem, 2010, 952(1-3): 31-35.
[17] 黄充,张军营,陈俊,等. 煤中噻吩型有机硫热解机理的量子化学研究 [J]. 煤炭转化, 2005, 28(2): 33-35. HUANG Chong,ZHANG Junying,CHEN Jun,et al. Quantum chemistry study on the pyrolysis of thiophene function alities in coal[J]. Coal Conversion, 2005,28(2): 33-35.
[18] 陈萍,顾明言,林郁郁,等. 含酮基团对煤焦异相还原NO的影响 [J]. 燃料化学学报, 2018, 46(5): 521-528. CHEN Ping,GU Mingyan,LIN Yuyu,et al. Effect of ketone group on heterogeneous reduction of NO by char[J]. Journal of Fuel Chemistry and Technology,2018, 46(5): 521-528.
[19] SAMOKHVALOV A. Heterogeneous photocatalytic reactions of sulfur aromatic compounds [J]. Chemphyschem, 2011, 12(16): 2870-2885.
[20] 谢丽丽. 模型化合物及煤热解过程中硫释放行为的研究 [D]. 呼和浩特:内蒙古大学, 2014.
[21] 么秋香. 渭北高硫煤中有机硫赋存状态及热解迁移规律研究 [D]. 西安:西安科技大学, 2015.
[22] GUO H,WANG X,LIU F,et al. Sulfur release and its transformation behavior of sulfur-containing model compounds during pyrolysis under CO2 atmosphere [J]. Fuel, 2017, 206: 716-723.
[23] GU Y,YPERMAN J,REGGERS G,et al. Characterisation of volatile organic sulphur compounds release during coal pyrolysis in inert, hydrogen and CO2 atmosphere [J]. Fuel, 2016, 184: 304-313.