超临界沥青喷雾造粒中的戊烷闪蒸CFD模拟

重油梯级分离技术作为重油轻质化的新工艺，它通过耦合渣油萃取和沥青喷雾造粒过程，有效的简化重油处理的工艺流程，减少设备成本。在此工艺流程中，处于超临界状态的戊烷的闪蒸速率对沥青造粒质量起到了关键作用。根据其减压过程中的质量和热量传递机理，改进了戊烷闪蒸的经验模型，并将其植入到CFD软件FLUENT中，使其能较为准确的预测闪蒸雾化的非平衡热力学过程。同时对气液戊烷和沥青的三相闪蒸流动过程进行了数值模拟，结果显示喷嘴结构是控制闪蒸速率的关键，直接影响了沥青造粒的质量；此外沥青相的加入为戊烷的相变过程提供了更多能量，提高了戊烷在喷嘴内的汽化率。

CFD Simulation of Supercritical Pentane Flash Boiling in Asphalt Granulation

Deep stage separation of heavy oil is a new technique invented in recent years,which can simplify process and reduces equipment cost by coupling the supercritical extraction and spray granulation.In this process,pentane flash-boiling rate is a key factor to quality control of asphalt granulation.According to the mechanism of mass and heat transfer in the process of pressure-driven phase change,an empirical model was developed and implanted into commercial code Fluent for pentane flash-boiling simulation.The flash-boiling flow simulation of the mixture pentane and asphalt was carried out.Simulation results show that the structure of nozzle has a vital effect on vaporization rate of pentane.The nozzle with conical section is fit for supercritical spray granulation.Furthermore,in this process,asphalt supplies more energy for the flash-boiling of pentane,which leads to the enhancement of the pentane vaporization rate.