کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6765310 | 1431590 | 2018 | 17 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Density functional theory investigation of gasification mechanism of a lignin dimer with β-5 linkage
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی انرژی
انرژی های تجدید پذیر، توسعه پایدار و محیط زیست
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چکیده انگلیسی
Density functional theory was employed to investigate gasification mechanism of β-5 linkage lignin in high temperature steam at B3LYP/6-31G++(d,p) level. Four possible decomposition reaction pathways and four successive reactions pathways were proposed. The equilibrium geometries of the reactants, transition states, intermediates and products were optimized. The activation energies, Gibbs free energy changes and enthalpy changes of each reaction step in gasification pathways were analyzed. From the calculation results of ÎHθ, it is concluded that the four decomposition reaction are endothermic below 1300 K, and exothermic exceed 1500 K. Furthermore, the ÎHθ of each reaction decrease with temperature increasing. From the ÎGθ calculation results, Path 2 and Path 3 occur spontaneously without temperature limited. Path 1 and Path 4, however, are spontaneous reaction above 700 K. It is not ensure that Path 5, Path 6, Path 7 and Path 8 can occur spontaneously. Comparison of activation energy of each reaction pathway, Path 2 is optimal decomposition reaction without a competitive reaction. The main products in decomposition reaction are 5-hydroxyphenyl-acetaldehyde (P5) and 12-hydoxymethyl-phenol (P4). Path7 is the optimal subsequent reaction with a competitive reaction, i.e., Path 5. The main products in subsequent reaction are CO, phenol and formaldehyde.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Renewable Energy - Volume 115, January 2018, Pages 937-945
Journal: Renewable Energy - Volume 115, January 2018, Pages 937-945
نویسندگان
Hang Zhang, Shengxiang Deng, Xiaolin Cao,