摘要
通过混酸氧化中温煤焦油沥青制备水溶性沥青,利用热重分析研究水溶性沥青的热解机理。根据Dollimore提出的TG/DTG曲线形状推断水溶性沥青热解反应动力学机理函数,利用Achar-Brindley-Wendworth方程拟合直线计算热解活化能。结果表明,中温煤焦油沥青在170~550℃阶段热转化动力学机理函数符合Dollimore的F1,最概然机理函数f(α)=1-α,反应为一级,活化能32.5 kJ/mol;水溶性沥青在155~460℃阶段热转化属于Dollimore的D_3,最概然机理函数1.5(1-α)^(2/3)[1-(1-α)^(1/3)]^(-1),反应机理是三维扩散,球形对称,活化能是82.8 k J/mol;在465~650℃范围内是亲水基团热解,符合Dollimore的F1,最概然机理函数f(α)=1-α,反应为一级,反应活化能41.6 k J/mol。水溶性沥青热稳定性较中温煤焦油沥青好。
Water-soluble pitch was prepared via oxidation by taking a mixture of sulfuric acid/nitric acid,using medium-temperature coal tar pitch as raw material,TGA experiments were conducted to study the pyrolysis mechanism of water-soluble pitch. Kinetics mechanism function was obtained by Dollimore ’s TG/DTG curve and activation energy by straight line fitted on Achar-Brindley-Wendworth equation. The result showed that transformation kinetics mechanism function of medium-temperature coal tar pitch conformed with Dollimore’s F1,the most probable mechanism function f（ α） = 1-α,first order reaction and activation energy was 32. 5 k J/mol when temperature ranges from 170 ℃ to 550 ℃. For water-soluble pitch it was conformed with Dollimore’s D3,the most probable mechanism function 1. 5（ 1-α）2/3[1-（ 1-α）1/3]-1,three-dimensional diffusion mechanism,the energy was 82. 8 k J/mol when temperature ranges from 155 ℃ to 460 ℃. From 465 650 ℃ hydrophilic group pyrolysis took place,conformed with Dollimore’s F1,the most probable mechanism function f（ α） = 1-α,first order reaction and activation energy was 41. 6 k J/mol. Water-soluble pitch was found to have higher stability as compared to medium temperature coal tar pitch.
出处
《应用化工》
CAS
CSCD
北大核心
2017年第7期1270-1273,共4页
Applied Chemical Industry
基金
国家自然基金(U1361126)
教育部博士点基金(20132120110001)
辽宁省教育厅先进煤焦化及煤资源高效利用工程研究中心开放课题基金(USTLKFZD201503)
