The steam ejector is used in the atmospheric and vacuum distillation process of petroleum refining
1.Raw material: crude oil, etc.
2.Products: naphtha, gas oil, residual oil, asphalt.
Atmospheric and vacuum distillation is the collective name of atmospheric distillation and vacuum distillation, which is basically a physical process: the raw material oil is divided into oils with different boiling point ranges (called fractions) in the distillation tower according to the evaporation capacity, and some of these oils are blended , Add additives and leave the factory in the form of products, a considerable part of which is the raw material for subsequent processing equipment.
Atmospheric and vacuum distillation is a petroleum processing process in an oil refinery, which is called a crude oil processing. It consists of three processes:
1.Desalination and dehydration of crude oil.
Crude oil generally contains salt and water, which can cause corrosion of equipment. Therefore, the crude oil is first desalted and dehydrated before entering atmospheric and vacuum pressure, usually by adding demulsifier and water.
The crude oil passes through the flowmeter, the heat exchange part and the brewery tower to form two parts. One part forms the oil on the top of the tower, which passes through the cooler and the flowmeter and then enters the tank area. This part is the light chemical oil (the so-called naphtha).One part forms the bottom oil of the tower, and then passes through the heat exchange part to enter the atmospheric pressure furnace and atmospheric pressure tower to form three parts, a part of diesel oil, a part of wax oil and a part of the bottom oil of the tower.The remaining tower bottom oil is further processed by vacuum furnace, vacuum tower to produce wax oil, residual oil and asphalt.
The respective yield: light gasoline or chemical oil accounted for about 1%, diesel oil accounted for about 20%, wax oil accounted for about 30%, residue and asphalt accounted for about 42%.
Atmospheric and vacuum processes do not produce gasoline products. Among them, wax oil and residual oil are converted into catalytic cracking to produce gasoline, diesel, kerosene and other refined oil; naphtha is directly sold to other small enterprises to produce solvent oil or enter the next step of deep processing , Generally, it is catalytic reforming to produce solvent oil or extract extractive compounds.
Atmospheric and vacuum unit is a distillation unit that processes crude oil once, that is, a processing unit that fractionates crude oil into gasoline, kerosene, diesel, wax oil, residual oil and other components. Crude oil distillation generally includes two parts: atmospheric distillation and vacuum distillation.
a.Atmospheric distillation tower
The so-called atmospheric distillation of crude oil is the distillation of crude oil at atmospheric pressure (or slightly higher than atmospheric pressure), and the distillation equipment used is called the atmospheric distillation tower of crude oil (or atmospheric pressure tower).
The remaining heavy oil components of atmospheric distillation have large molecular weight and high boiling point, and are easy to decompose at high temperature, which makes the distillated products deteriorate and produce coke, destroying the normal production.Therefore, in order to extract more light components, the boiling point range of the raw oil to be distilled is often reduced by reducing the distillation pressure.This distillation process, which takes place under reduced pressure, is called reduced pressure distillation.
b.Vacuum distillation tower
Vacuum distillation is a distillation process carried out under a negative pressure of less than 100 kPa.The core equipment of vacuum distillation is the vacuum tower and its vacuum system.
The vacuum equipment of the decompression tower is usually a steam ejector (also called a steam suction pump) or a mechanical vacuum pump. Among them, mechanical vacuum pumps are only used in some dry vacuum distillation towers and vacuum towers in small refineries, while steam ejectors are widely used.