According to the type of product they produce, the petrochemical industry feeds on two types of gas and liquid feed. Eight materials, ethylene, propylene, butadiene, methanol, benzene, toluene, xylene, and ammonia are considered as the basic materials of petrochemicals. The basic materials of petrochemical industry include light olefins (ethylene, propylene, butylene), aromatics (benzene, toluene and xylene) and synthesis gas (ammonia and methanol).

Feedstuffs used in the petrochemical industry can be divided into three general groups: olefins, aromatic substances and the third group which includes synthesis gas and minerals. Light olefins account for more than 60% of the production share of these eight basic petrochemical materials in the whole world.

The production units where light olefin (ethylene, propylene, and further on the production chain of polyethylene and polypropylene) are their main products, mainly from ethane gas and liquid petroleum products (naphtha, propane, butane, raffinate, etc.) Refineries produce, use.

In the production of polyethylene, mainly ethane is used, in the production of propylene, mainly propane is used, and in the production of butylene, butane is used. The primary sources for the production of aromatics are gas condensate and naphtha. During catalytic conversion processes, as well as pyrolysis gasoline produced in steam cracking units of refineries, they are used to produce aromatics. The primary sources for the production of synthesis gas are mainly methane gas and coal.