Working principle

• Filtration Stage:

After the PTA hydrogenation reaction is completed, the reaction products enter the disc filter from the bottom of the reactor. The material is driven by a pressure difference and flows in a channel between the discs. Due to the presence of the filter media on the disc, the impurity particles in it are trapped on the surface or inside the filter media as the material passes through.

For example, trace metal impurities that may be present in the PTA reaction (such as palladium, cobalt, etc. in the catalyst) will be intercepted by the filter, while the pure PTA product can pass through the filter media and enter the outlet side of the filter.

• Backwash stage:

As the filtration process progresses, the impurities on the surface of the disc will gradually accumulate, resulting in an increase in filtration resistance and a decrease in filtration efficiency. When a certain pressure drop or filtration time is reached, the filter initiates a backwash program.

During backwashing, the clean fluid (such as hydrogen, deionized water or organic solvent, etc.) will be reversed from the outlet of the filter, so that the impurities on the disc will be washed away from the filter medium. The rinsed impurities are discharged out of the filter through a dedicated drain with the backwash fluid, thus restoring the filter's filtration capacity.

Advantages:

• Ensure product quality：It can effectively remove impurities in PTA products and significantly improve the purity of PTA. High-purity PTA is essential for subsequent processes such as polyester synthesis, because the presence of impurities may affect the polymerization reaction of polyester, resulting in a decrease in the quality of polyester products, such as reducing the strength, color and other properties of polyester fibers.

• Extend the life of the equipment: If the intercepted impurities enter the downstream equipment, they may cause wear and corrosion to the equipment. Disc filters can prevent the adverse effects of these impurities on subsequent equipment such as pipes, pumps, heat exchangers, etc., prolong the service life of equipment in the entire production system, reduce the frequency of equipment maintenance and replacement, and reduce production costs.

• Stable production process: Its stable filtration performance can ensure that the quality and flow of reaction products remain relatively stable during the PTA production process. It will not cause interruption or fluctuation of the production process due to the blockage of impurities, which is conducive to improving production efficiency and product consistency.

  
  

Application:

• In the PTA production process, disc filters play an indispensable role at the bottom of the hydrogenation reactor, whether it is the traditional high-temperature oxidation method combined with the hydrorefining process, or the emerging green chemical process to produce PTA. It can be applied to PTA production plants of different sizes, from small lab-scale plants to large-scale industrial production plants.

• Petroleum refining: In the process of hydrorefining, hydrocracking, etc., it is used to filter the oil after the reaction, remove the catalyst particles, metal impurities, sulfides, etc., improve the quality of the oil, and meet the requirements of subsequent processing and use.

• Chemical production field: For example, in the process of aromatic hydrogenation, olefin hydrogenation and other reactions, the reaction products are filtered to ensure the purity and quality of the product and prevent impurities from adverse effects on downstream equipment and processes.