调合石蜡的相平衡参数和相变动力学特性

使用正规溶液模型的Scatchard-Hildebrand方程对调合石蜡的熔点、浊点以及固-液和组元相变速率进行了计算.以切片石蜡作为被调合石蜡的计算结果表明,烷烃的相变温度和切片石蜡相近时,该烷烃对调合石蜡的熔点、浊点以及相变动力学特性影响较小.增加C22类轻质烷烃的质量分数,调合石蜡的熔点、浊点降低;熔程内较低温度下,轻质烷烃相变速率变慢,重质烷烃相变速率变快.增加C35类重质烷烃的质量分数,调合石蜡的浊点升高,熔点呈现复杂的变化,对C24以下烷烃的相变速率几乎没有影响,C25以上烷烃在熔程内较低温度下相变速率变慢.计算结果可以为相变储能中选用具有适当相变温度及相变动力学特性的调合石蜡提供指导.

Calculation of phase equilibrium and phase change dynamics of blended paraffin

The Scatchard-Hildebrand equation of regular solution is used to calculate the melting temperature,cloud temperature,and phase change dynamics of blended paraffin.The equation is confirmed for the calculation of phase equilibrium and phase change dynamics of blended paraffin.Calculation results of a paraffin show that alkanes having phase change temperature near to the paraffin have little influence on phase equilibrium and phase change dynamics of blended paraffin.The melting temperature and cloud temperature of blended paraffin decrease as content of light alkanes increases,while phase change speeds of light alkanes decline at low temperature within melting scope.The cloud temperature of blended paraffin increases with the content increase of heavy alkanes,the change of melting temperature is complex in this instance.The phase change speed of C22 to C24 has no relation with the content of C35,while the speed of other alkanes is slow-down as the content of C35 increases.This calculation can provide a guide for the choice of blended paraffin with appropriate phase equilibrium parameters and phase change dynamic characteristics used for thermal energy storage.