(A) PTA production process
PTA is a low-end product of petroleum. Petroleum produces naphtha (alias light gasoline) through a certain process, extracts MX (mixed xylene) from naphtha, and then extracts PX (p-xylene). PTA uses PX (65%-67%) as raw material, acetic acid as solvent, and air oxidation (35%-33% oxygen) under the action of catalyst to produce crude terephthalic acid. Then the crude terephthalic acid is hydrofined to remove impurities, and then the refined terephthalic acid product, namely PTA finished product, is obtained through crystallization, separation and drying.
There are manufacturers of crude terephthalic acid at home and abroad, such as EPTA of Sanxin Petrochemical and QTA of South Korea. There is no later refining process in the production process. Low cost and obvious price advantage, which can meet the needs of different polyester enterprises.
(B) the use of PTA
PTA is one of the important bulk organic raw materials, which is widely used in chemical fiber, light industry, electronics, construction and other aspects of the national economy. At the same time, the application of PTA is relatively concentrated. More than 90% of PTA in the world is used to produce polyethylene terephthalate (PET). The production of 1 ton PET requires 0.85-0.86 tons of PTA and 0.33-0.34 tons of MEG. Polyester includes fiber chips, polyester fibers, bottle chips and film chips. In the domestic market, 75% PTA is used to produce polyester fiber; 20% is used to produce bottle-grade polyester, which is mainly used for the packaging of various beverages, especially carbonated beverages; 5% is used in film-grade polyester, mainly used in packaging materials, films and adhesive tapes. It can be seen that the downstream extension products of PTA are mainly polyester fibers.
Domestic polyester production capacity statistics in 2003-2005
age
fibre-grade
Bottle grade
Film grade
be equal to
2003
1 166.3
147
6.7
1320
2004
1598.3
197
2 1.7
18 17
2005
1657.3
27 1
3 1.7
1960
Polyester fiber, commonly known as polyester. Belonging to synthetic fibers in chemical fibers. Synthetic fiber manufacturing industry is the largest and most branched sub-industry in chemical fiber industry. Besides polyester, its products include acrylic fiber, nylon and spandex. In 2005, China's chemical fiber output was16.29 million tons, accounting for 37% of the world's total output of 44 million tons. The output of synthetic fiber accounts for 92% of the total chemical fiber, while polyester fiber accounts for 85% of synthetic fiber. Polyester is divided into filaments and staple fibers, with filaments accounting for about 62% and staple fibers accounting for about 38%. There are two methods to produce filaments and staple fibers: one is to produce chips from PTA and MEG and melt spinning; One is that PTA and MEG do not produce chips in the production process and spin directly.
Polyester can be used to make special materials, such as bulletproof vests, safety belts, tire cords, fishing nets, ropes, filter cloth and rim materials. But its main use is as a textile raw material. In domestic textile raw materials, cotton and chemical fiber account for 90% of the total. China's chemical fiber production ranks first in the world. In 2005, of the 26.9 million tons of fiber processing in China textile industry, the output of chemical fiber accounted for 6 1%. The polyester in chemical fiber accounts for nearly 80% of the total chemical fiber. Therefore, polyester is the main raw material of textile industry. Polyester filaments are used by textile enterprises to produce chemical fiber fabrics, and polyester staple fibers are generally blended with cotton. In general, cotton yarn accounts for 60% and polyester accounts for 30-35%. However, the consumption of both has been replaced by price changes. Simply put, the raw material of PTA is PX, and the source is petroleum. PTA accounts for 75% of the total polyester, while 78% of chemical fiber is polyester. This is the origin of the term "PTA".