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.