Pressure-reduced oil transfer line
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In atmospheric and vacuum distillation units, crude oil is heated in a vacuum furnace and then enters the vacuum tower via a vacuum transfer line. In the past, domestic plants mostly used short and coarse-type low-pressure transfer lines to minimize the pressure drop across these lines; however, in recent years, several large-scale atmospheric and vacuum distillation unit process packages introduced in China (such as the Dalian Shell process package and the Huangdao KBC process package) have employed transfer lines with higher pressure drops, keeping the pressure at the exit of the vacuum furnace at around 300 mmHg(A). I would like to ask everyone for their understanding of the design of these two types of transfer lines, as well as the design methods for the latter type – including when and how to increase the diameter of such lines. Please share your insights; thank you!
The outlet of the vacuum furnace is connected to the oil transfer line at different points along it, so no diameter expansion is required. The oil transfer line is a large collection pipe.
I’m sorry, what I meant is the transition section plus the oil transfer line. It includes the design of both the transition section and the oil transfer line, with the transition section being the key part!
Could my colleagues please provide an explanation for why a low-temperature oil transfer line is installed only between the vacuum furnace and the vacuum tower, but not between the atmospheric furnace and the atmospheric tower?
This post was last edited by There’s a call on 2014-8-1 23:20. I think you are referring to the low-speed oil transfer line. Vacuum distillation involves using vacuum, or negative pressure, to allow more of the lighter components in the crude oil to be distilled out at a temperature that prevents cracking. Inside the vacuum furnace, as the temperature of the oil rises, the amount of vaporization increases. When the oil reaches the middle section of the furnace tubes, it begins to widen. Generally, three or more such widening stages are required inside the furnace in order to reduce the flow velocity, minimize pressure drops, and prevent erosion and corrosion. After coming out of the constant-bottom oil tank, the fluid continues to expand in diameter as it moves into the oil transfer line. The oil transfer line operates at reduced pressure and at low speed, which ensures a higher degree of vaporization in a vacuum environment as well as reduced risk of corrosion due to high temperatures. This is done both for safety reasons and to achieve the desired process objectives. Atmospheric distillation is a process that separates light and heavy components under normal pressure by utilizing the boiling points of different components, with varying process conditions. Crude oil is also expanded in diameter in the constant-temperature furnace and the oil transfer line, although the flow velocity is higher there.