An important part of the chemical industry plays an important role in the development of the national economy and is one of the pillar industries in my country. Petrochemical industry refers to the processing industry that uses petroleum and natural gas as raw materials to produce petroleum products and petrochemical products. Petroleum products, also known as oil products, mainly include various fuel oils (gasoline, kerosene, diesel, etc.) and lubricants, as well as liquefied petroleum gas, petroleum coke, paraffin, and asphalt. The process of producing these products is often referred to as petroleum refining, or oil refining for short. Petrochemical products are obtained by further chemical processing from the feedstock oil provided by the refining process. The first step in the production of petrochemical products is to crack raw oil and gas (such as propane, gasoline, diesel, etc.) to produce basic chemical raw materials represented by ethylene, propylene, butadiene, benzene, toluene, and xylene. The second step is to produce a variety of organic chemical raw materials (about 200 kinds) and synthetic materials (plastics, synthetic fibers, and synthetic rubbers) with basic chemical raw materials. The production of these two-step products belongs to the scope of petrochemical industry. Organic chemical raw materials continue to be processed to produce more varieties of chemical products, which are not traditionally included in the scope of petrochemicals. In some materials, the synthesis of ammonia and urea using natural gas, light gasoline, and heavy oil as raw materials, and even the production of nitric acid are also included in the petrochemical industry.