The main foreign production brands of Fischer-Tropsch wax are SASOL of South Africa and Shell of the Netherlands. In recent years, China's research on Fischer-Tropsch synthesis technology has also begun to increase. Relying on the Fischer-Tropsch synthesis technology of coal-based oil with independent intellectual property rights, a series of coal-based oil products have been successfully developed.
Crude wax, one of coal-based synthetic oil series products, is the raw material for refining Fischer-Tropsch wax series products. Through advanced extraction and distillation technology, Fischer-Tropsch synthetic crude wax can be further cut to produce a series of Fischer-Tropsch synthetic waxes, generally named according to the melting point, the main product models are 60, 70, 95, 100, 105, 110, 115.
The key technology of Fischer-Tropsch wax production lies in catalysts. Commonly used catalysts are iron-based catalysts and cobalt-based catalysts. Iron-based catalysts are mainly used to produce Fischer-Tropsch synthetic waxes with a melting point below 105°C, and only cobalt-based catalysts can be used for Fischer-Tropsch synthetic waxes with higher melting points. The appearance and performance of Fischer-Tropsch wax produced by cobalt-based catalyst are better than those produced by iron-based catalyst.
Fischer-Tropsch waxes are mainly composed of linear, saturated high-carbon alkanes with relative molecular weights of 500-1000, which endow the chemical with a fine crystal structure, high melting point, narrow melting point range, low oil content, low penetration, low mobility, low melt viscosity, hardness, abrasion resistance and high stability.
According to needs, the Fischer-Tropsch process can synthesize alkanes with different chain lengths to change the molecular weight of the final product to form serialized products.
The significant difference between Fischer-Tropsch waxes and general-purpose polyethylene waxes (PE waxes) is: (a) Molecular weight. The molecular weight of Fischer-Tropsch wax is much lower than that of PE wax, with less branch chains and high crystallinity. (b) Fischer-Tropsch wax is a saturated straight-linked alkane without double bonds, with strong anti-oxidation ability and good weather resistance. (c) The viscosity of Fischer-Tropsch wax is much lower than that of PE wax, only about 10. The same lubrication effect can be achieved with less dosage. The usage amount is only 70-80% of PE wax.