[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials and storage methods of coking xylene, national standard for coking toluene

PROPERTIES OF COKING XYLENE

Coked xylene (Coke-based Xylene) is a kind of chemical products extracted from coal tar, mainly including o-xylene, m-xylene and p-xylene. It is a colorless and transparent liquid with an aromatic odor, a density of about 0.86g/cm³, a boiling point between 138°C and 144°C, soluble in most organic solvents, but almost insoluble in water. Coked xylene is flammable, and vapor and air can form an explosive mixture, so it is necessary to pay attention to safety protection during use and storage.

Coking xylene use

Coking xylene has a wide range of applications in the chemical industry. Its main use is as a solvent and intermediate. In terms of solvents, xylene is often used to dissolve and dilute paints, coatings, dyes and resins. In terms of intermediates, coker xylene is an important raw material for the production of terephthalic acid (PTA) and xylene diisocyanate (XDI), which are widely used in the manufacture of polyester fibers, plastics and coatings. Xylene is also used as an intermediate in industries such as pharmaceuticals, spices and pesticides, and has important commercial value.

Upstream raw materials

The production of coker xylenes relies mainly on coal tar and petroleum cracking. Coal tar is a by-product of the coking process that contains large amounts of aromatic compounds, including xylenes. Coker xylenes can be extracted from coal tar by fractionation and rectification techniques. Petroleum cracking is also an important way to produce xylene. Through the catalytic cracking of petroleum, mixed aromatics containing xylene can be obtained, and then high-purity xylene products can be obtained through separation and purification. The production of coker xylenes may also require some auxiliary feedstocks, such as hydrogen for hydrofining, catalysts for cracking and separation, etc.

Downstream Products

The downstream products of coker xylene are rich and varied, the most important of which are terephthalic acid (PTA) and xylene diisocyanate (XDI). PTA is a key raw material for the production of polyester fibers and polyester resins, which are widely used in the manufacture of textiles, beverage bottles and packaging materials. XDI is an important chemical intermediate for the production of high-performance coatings, adhesives and elastomers. Xylene can also be oxidized to produce phthalic anhydride and isophthalic acid, which are also widely used in the production of plastics, coatings and dyes.

storage method

Since coker xylene is flammable and volatile, its storage requires special attention to safety measures. Generally, coked xylene should be stored in a cool, ventilated, dry dedicated storage tank, away from fire and heat sources. The material of the storage tank should be non-corrosive steel to xylene, and the storage tank must have good sealing to prevent steam leakage. The storage area shall be provided with fire protection facilities, such as fire extinguishers and fire water sources, to cope with sudden fire. Leak-proof dike shall be set around the storage tank to prevent environmental pollution and potential safety hazard caused by xylene diffusion during leakage.

Environmental Impact and Safety Protection

The production and use of coking xylene may have a certain impact on the environment and human health. Its vapor has a stimulating effect on the respiratory system and skin, and long-term exposure may lead to chronic poisoning. Therefore, effective ventilation and personal protection measures must be taken during production and use, such as wearing gas masks, gloves and protective clothing. Production enterprises should also strengthen the treatment of waste gas, waste water and waste residue to prevent the discharge of pollutants from harming the environment. Regularly detect the concentration of xylene in the air of the workshop to ensure that it is within a safe range and reduce the health hazards to workers.

Market Analysis and Prospects

The demand for coking xylene in the market is closely related to the global economic development. With the advancement of industrialization, the demand for chemical products continues to grow, driving the development of the xylene market. Especially in Asia, with the rapid industrialization of China, India and other countries, the demand for p-xylene and its downstream products continues to increase, and the market prospect is broad. Market competition is also intensifying. Manufacturers need to continuously improve their technical level, reduce production costs, and improve product quality in order to be invincible in the fierce market competition.

Conclusion

As an important chemical raw material, coking xylene has a wide range of uses and important commercial value. Its production relies on upstream feedstocks such as coal tar and petroleum cracking, which are mainly used to produce downstream products such as terephthalic acid and xylene diisocyanate. It is necessary to pay attention to safety protection during storage and use to reduce the impact on the environment and human health. In the future, with the advancement of global industrialization, the coking xylene market is expected to continue to grow, but it is also facing the dual challenges of technology and market competition.