Crude benzene: raw coking benzene with foul smell.

Refined benzene: refined benzene for removing odor.

Pure benzene: benzene after further purification of refined benzene.

Crude benzene refining: the process of converting crude benzene into refined benzene.

Toluene: There is a methyl group on the benzene ring.

Xylene: There are two methyl groups on the benzene ring.

Hydrogenated benzene, hydrogenated toluene and hydrogenated xylene: products produced by hydrofining process.

Benzene was originally a petrochemical product. Coking crude benzene extracted from coal tar can be used in the case of oil shortage. However, coking crude benzene tastes bad because it is not pure benzene. Besides toluene and xylene, it also contains a lot of styrene, indene, indene oxide, dicyclopentadiene, carbon disulfide and sulfur nitrogen oxides, which have a pungent smell and must be hydrogenated and deodorized.

Crude benzene hydrotreating technology is a technology to remove sulfur compounds and non-aromatic hydrocarbons from crude benzene by catalytic hydrogenation to produce high-quality benzene hydrocarbons. Catalytic hydrogenation is usually divided into two processes: high temperature and high pressure and low temperature and low pressure. The products of high temperature hydrogenation are only benzene, but there are no toluene and xylene. The product produced by this method is also called refined benzene. Besides benzene, the products of low-temperature hydrogenation also include toluene and xylene (separation products).

The crude benzene hydrofining unit has advanced technology, and the benzene produced is of high purity, which is basically consistent with petroleum benzene products. It can be effectively separated from toluene and xylene, and the products are pure benzene, toluene, xylene (including o-xylene, m-xylene and p-xylene), trimethylbenzene and heavy benzene.