The crude oil processing process first divides the crude oil into different straight-run distillates according to the boiling point requirements of different products, and then removes the non-ideal components in these distillates according to the quality standards of the products; The required components, and then obtain a series of qualified petroleum products.

Refiners must first address the splitting of crude oil and the separation of various petroleum fractions during processing. Distillation is one of the most economical and easiest separation methods commonly used.

The first process of crude oil in almost all refineries is crude oil distillation (called tap), such as top distillation and atmospheric and vacuum distillation. The so-called primary processing of crude oil mainly refers to crude oil distillation.

Distillation units are generally called atmospheric and vacuum units. Atmospheric and vacuum distillation unit is one of the most important units in oil refining enterprises. The annual capacity of the refining and chemical enterprise is 10,000 tons/year (if not specified), which refers to the annual processing capacity of the atmospheric column of the atmospheric and vacuum distillation unit. The scale of the atmospheric and vacuum distillation unit determines the type of oil processed, the yield of residual oil and the refining profit of the refining and chemical enterprise. Understanding and researching atmospheric and vacuum distillation units is an essential homework for petrochemical researchers.

Gasoline …………<130℃

Kerosene …………130~250 ℃

Diesel …………250~300℃

Heavy diesel………… 300~350 ℃

Wax oil…………350~520℃

Residual oil…………>520 ℃

A general atmospheric and vacuum distillation unit consists of several parts:

1) Electric desalination system

2) Preliminary distillation column (some units or refineries may not have it)

3) Flash tower (some units or refineries may not have it)

4) Atmospheric pressure tower

5) Decompression tower