正构烷烃分布对石蜡相变热的影响

Influence of n-Alkanes Distribution to The Phase Changing Enthalpy of Paraffin Wax

使用尿素络合法由柴油制备石蜡,在20℃、40℃、60℃下分别进行2～6h的反应,用气相色谱和差示扫描量热仪分析产品的正构烷烃组成和热性能。结果表明在每个温度下随络合时间的增加,碳数不同的正构烷烃在产物中的含量随时间变化趋势不同。石蜡的正构烷烃含量各异,相变热亦不同。将络合制备的石蜡中相变热最高的一组进行精馏,通过比较精馏前后石蜡的正构烷烃分布和相变热,发现精馏后的石蜡正构烷烃分布主要集中在3个组分上,其相变热更高。在与单体正构烷烃对比后,精馏分割的石蜡符合作相变材料的热性能和经济条件。

Paraffin wax was prepared from diesel by urea adduct method at 20 ℃,40 ℃ or 60 ℃ for 2~6 hous.The outcome was analyzed in the aspects of n-alkanes distribution and phase changing enthalpy by gas chromatography and differential scanning calorimeter(DSC).With the time increasing at each temperature,the n-alkanes of different carbon numbers contained in the paraffin wax had the dissimilar current,and led to the phase changing enthalpy of paraffin wax diversely.Sequential research went to compare the n-alkane distribution and phase changing enthalpy between the aforementioned paraffin wax with highest phase changing enthalpy and its distillate.And as the result indicated,the rectified paraffin wax had a more narrow range of n-alkanes distribution and concentrated on three components,and higher phase changing enthalpy,which made it a promising and economical phase change material after a compare to single n-alkane.