**2.6 Crude distillation unit (CDU) used in Russia compared to the typical model**

Based on the evaluation of the concept of the technological scheme for the construction of a technological scheme of crude distillation unit at refineries in Russia. The topping column K-1 in most cases is a simple design as shown in **Figure 13** [28], although it fractionates the crude oil into the many components like ethane, light gasoline, etc.. There are schemes in which light gasoline is displayed under the distillate in the top of the column, and heavy gasoline on the side flanks of the column. The topping column K-1 collects 50–60% of the potential of light gasoline. The residues of column K-1 are therefore the raw material of the main atmospheric column. The composition of this raw material is weighted in such a way that an excessively high feed temperature is required, permissible temperature (380°C). The singularities of the topping column K-1 operation are as follows [1, 28]:


#### **Figure 13.**

*Possible schemes of operation with oil topping column K-1. (a) Column K-1 with back topped crude. (b) Column K-1 with heavy gasoline and back topped crude. (c) Column K-1 without back topped crude.*

• The relatively small enthalpy of crude oil (220°C) introduced into the column does not create sufficient heat flow for distillation, therefore, it is necessary to introduce additional heat in the form of hot jet reflux;

• Pressure, bar – no more than 3.0.

*DOI: http://dx.doi.org/10.5772/intechopen.90394*

• Heavy gasoline (or military jet fuel)

The main atmospheric column K-2:

• Pressure, bar – no more than 1.4.

• Heavy gasoline (or military jet fuel)

• Kerosene (light distillate or jet fuel)

• Middle distillates or light gas oil (LGO) – Diesel

• Heavy distillates – atmospheric gas oil (AGO) or heavy gas oil (HGO)

The distillation processes are the processes of oil separation into more or less homogeneous fractions without chemical conversion of its constituent substances. The process of separation of liquid substances by their boiling temperatures is atmospheric and vacuum. The atmospheric distillation can be carried out in the

• With a single separation – furnaces and separation of distillate in one (main)

• Double separation in two distillation columns- in the pre-evaporation column k-1 with separation of light gasoline fractions and the main column-2;

The oil topping column K-1, in atmospheric distillation, collects 50–60% of the potential of light gasoline from oil [28]. Otherwise, the composition of oil for the atmospheric column K2 is so weighted that an excessively high supply temperature is required, permissible temperature (380°C). The oil topping column K-1 is especially important in the general crude distillation unit technology in Russia. We know that the choice of flow process technology is dictated by the physicochemical properties of the oils and their compounds. Indeed, the choice of structure of

• Crude column bottoms -atmospheric residue or topped crude

The typical products of K-2 are:

• Top temperature, °С – no higher than 350;

• Low temperature, °С – no higher than 150;

• Light straight run naphtha (light gasoline or light naphtha)

The typical products of K-1 are;

*Crude Distillation Unit (CDU)*

• Gases

• Topped crude

following ways:

**133**

distillation column k-2;

• Gradual separation.

• Maintaining high pressure in the column to ensure air and water condensation of light gasoline fractions in condensers-refrigerators (separators).

The purpose of this column is to extract from the oil the remains of dissolved gas (if the oil has not been stabilized) and a light gasoline fraction with a boiling point of 85°C. After atmospheric residue of K-2 shipped to the vacuum column K-5 for to obtain vacuum distillates (heavy gasoil) and tar. In order to illustrate our argument, a typical P&ID flow diagram process of the atmospheric distillation unit in Russian refineries is presented in **Figure 14**.
