What is Aromatic unit in oil refinery?

 

In the refining process, one of the most important units is the Aromatic unit, which is responsible for producing high-purity benzene, toluene, and xylenes (BTX) from naphtha feedstocks. The production of these chemicals is important for a variety of applications, including the production of plastics, resins, synthetic fibers, and pharmaceuticals.

The Aromatic unit is a complex system that consists of several interconnected units and processes. In this article, we will explore the Aromatic unit in detail, including its function, process flow, equipment, and safety considerations.

Function of the Aromatic Unit

The primary function of the Aromatic unit is to separate and purify BTX chemicals from naphtha feedstocks. The process begins with the distillation of the naphtha feedstock in a distillation column. The column is designed to separate the components of the naphtha based on their boiling points.

After the initial distillation, the BTX chemicals are further separated and purified through a series of processes. These processes include extraction, isomerization, transalkylation, and hydrogenation.

The extraction process involves the use of a solvent to extract the BTX chemicals from the naphtha. The solvent is then separated from the BTX chemicals through a series of distillation and fractionation steps.

The isomerization process involves the conversion of non-aromatic hydrocarbons into aromatic hydrocarbons. This process is important because it increases the yield of BTX chemicals from the naphtha feedstock.

The transalkylation process involves the conversion of less desirable BTX chemicals into more desirable ones. For example, toluene can be converted into benzene and xylene through transalkylation.

Finally, the hydrogenation process involves the removal of impurities, such as sulfur and nitrogen, from the BTX chemicals. This process is important because impurities can negatively impact the quality of the final product.

Process Flow of the Aromatic Unit

The Aromatic unit is a complex system that consists of several interconnected units and processes. The process flow of the Aromatic unit is as follows:

Naphtha Feedstock: The process begins with the introduction of naphtha feedstock into the system. The feedstock is typically a light hydrocarbon mixture that is derived from crude oil.

Distillation Column: The naphtha feedstock is then distilled in a distillation column. The column is designed to separate the components of the naphtha based on their boiling points.

Extractor: The BTX chemicals are extracted from the naphtha using a solvent. The solvent is then separated from the BTX chemicals through a series of distillation and fractionation steps.

Isomerization Unit: Non-aromatic hydrocarbons are converted into aromatic hydrocarbons through the isomerization process. This increases the yield of BTX chemicals from the naphtha feedstock.

Transalkylation Unit: Less desirable BTX chemicals are converted into more desirable ones through the transalkylation process. For example, toluene can be converted into benzene and xylene through transalkylation.

Hydrogenation Unit: Impurities, such as sulfur and nitrogen, are removed from the BTX chemicals through the hydrogenation process.

Product Storage: The final products, which are high-purity benzene, toluene, and xylenes, are stored in product tanks before being shipped to customers.

Equipment Used in the Aromatic Unit

The Aromatic unit is a complex system that requires a variety of equipment to operate. Some of the most important pieces of equipment used in the Aromatic unit include:

Distillation Column: The distillation column is the most important piece of equipment in the A