Abstract:

The transfer line refers to a pipeline connection between furnace and vacuum column in the crude oil distillation unit. A well-designed transfer line can increase the evaporation rate of the feed in the vacuum distillation tower，improve oil product quality and save energy for the vacuum distillation tower. According to the existence of sudden enlargement，diffuser and T-connection，particularly to the connected mode of transition section and the low flow rate section，the typical vacuum transfer lines are divided into A，B type and C type. Using the one-dimensional，two-phase flow model developed on the basis of pressure drop model and the multi-stage flash model，the analysis of axial pressure，temperature，flow rate and evaporation rate of seven industrial transfer lines was made. The results showed that the pressure drop of Type A was the greatest because the transition section merged to the low flow rate section directly. The pressure in the transfer lines of Type B decreased gradually，and its pressure drop was the lowest. The pressure drop of Type C with two-stage enlargement structure decreased sharply twice and its pressure drop was lower.

摘要：

减压转油线作为原油蒸馏中减压单元的重要组成部分，对于减压装置的稳定操作、减压深拔、改善油品质量和节能意义重大。本文在采集大量工业数据的基础上，按照转油线结构中是否存在突扩、渐扩和三通等，特别是根据过渡段与低速段的连接方式，将典型的减压转油线分为A型、B型和C型。利用基于多级闪蒸模型和压降模型的一维两相流模型对七套工业转油线内压力、温度、流速和汽化率沿转油线轴向的变化情况进行计算。结果表明，A型直插式转油线合流处压力陡降，压降最大；B型渐扩式转油线合流处压力缓慢下降，压降最小；C型二次扩径式结构压力出现两处陡降，压降较小。