Improvement of Cleaning Process for PET screen changer

In the production process of polyethylene terephthalate P (PET) by terephthalic acid and ethylene glycol acetylation, the following reasons often cause the material anomalies:

(1) the condensation time is too long, the material flow is not smooth, resulting in the dead angle resulting in yellow and black "pot scale";

(2) because of the leakage of the system, the temperature control is relatively high, which causes the thermal oxidation to increase the gel content;

(3) careless operation, the production worker. Unstable technology will cause fluctuation of material viscosity;

(4) uneven addition of additives such as titanium dioxide, resulting in precipitation and increase of granules. This requires the use of melt filters to remove impurities, agglomerations and other general contaminants in the melt in the production process, so that the melt through the melt filters can achieve a certain degree of uniformity and purity, and meet the requirements of downstream chips and spinning.

Melt filter (mesh screen changer) filter element is usually made of non-woven 304 stainless steel fiber felt, the diameter is about 0.1 mm, the filtering accuracy is from 20um to 100um, and it has the characteristics of high temperature, high pressure and corrosion resistance.