Reduced pressure distillation method and device

Abstract

The invention discloses a reduced pressure distillation method and a reduced pressure distillation device. A flash tower is arranged between a reduced pressure furnace and a reduced pressure distillation tower, an oil transfer line is canceled, a reduced pressure distillation raw material is heated in the reduced pressure furnace and then directly enters the flash tower, and gas-liquid separation is performed in the flash tower; the liquid phase, namely flash bottom oil, discharged from the bottom of the flash tower is introduced into the reduced pressure distillation tower; and the gas phase, namely flash top gas, discharged from the top of the flash tower is condensed into liquid phase, and the liquid phase is led out of the device. According to the reduced pressure distillation method and the reduced pressure distillation device using the flash tower in back of the reduced pressure furnace, on the one hand, the yield of reduced pressure distillate is improved; and on the other hand, the conventional reduced pressure oil transfer line is canceled, the operation load of the reduced pressure tower is reduced, and the diameter of the reduced pressure tower can be properly reduced so that the equipment investment is saved and the operation cost is lowered.

Description

Technical field [0001] The invention belongs to the field of petroleum refining, and specifically relates to a process method and device for the vacuum distillation of crude oil, and more specifically, a vacuum distillation method that is beneficial to increase the extraction rate, reduce energy consumption, and save investment. Device. technical background [0002] Crude oil atmospheric and vacuum distillation process is the first process of petroleum refining, which divides crude oil into components of different distillation ranges by distillation to meet the process requirements of products and downstream equipment for raw materials. The light oil yield and energy consumption directly affect the economic benefits of petroleum refining. The conventional crude oil atmospheric and vacuum distillation process mostly adopts the process of "two furnaces and three towers": the crude oil enters the initial distillation tower (or flash distillation tower) after pretreatment, and then ...

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Problems solved by technology

Since the oil transfer line must be more than 15m (to ensure that the gas-liquid phase has a certain stratification time, which is beneficial to improve product quality and the extraction rate of the vacuum tower), the large-diameter and long-distance oil transfer line occupies a large part of the investment in vacuum distillation equipment. At the same time, factors such as heat loss and pressure drop increase are not conducive to the operation of the vacuum distillation tower, and the resulting thermal stress and thermal displacement cause certain difficulties in design and installation in terms of safety.

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