Method for separating and purifying polycarbonate glue solution

Abstract

The invention relates to a method for separating and purifying polycarbonate glue solution. By means of an efficient separation washing and purifying process of using two oblique plate separators, two centrifugal machines and a fiber bed coalescence separator, the method is quick and efficient in separation washing and effective, and aqueous phase separated from the centrifugal machines is further treated to simplify operations of the centrifugal machines. The aqueous phase discharged from the centrifugal machines and the oblique plate separators are mixed with cooling liquid of the centrifugal machines to extract the polycarbonate glue solution and then re-separated through the fiber bed coalescence separator to minimize organic phase loss, and accordingly loss of the polycarbonate glue solution is reduced. Further, the aqueous phase separated from the fiber bed coalescence separator can directly enter a waste water treatment system, so that difficulty in waste water treatment is lowered.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a method for separating and purifying polycarbonate glue. Background technique [0002] At present, the production of polycarbonate mainly includes phosgene interfacial polycondensation method and melt transesterification method, among which phosgene interfacial polycondensation method is currently the most widely used preparation method. The phosgene interface polycondensation reaction is simple, but the post-treatment is more complicated. The product after the reaction must be separated and purified, and the solvent can be removed to obtain the final product. The quality of the separation and purification effect is directly related to the quality of the polycarbonate product. [0003] After the phosgene interface polycondensation reaction is completed, the product exists in two phases, an organic phase and an aqueous phase. There are impurities such as sodium chloride, sodium c...

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Problems solved by technology

[0005] Chinese patent CN1461322A describes the method of using a tray decanter and a coalescer decanter in series, and then connecting a centrifuge to separate and purify the product after interfacial polycondensation, wherein at least one tray decanter or coalescer decanter is used , Three centrifuges, the polycarbonate resin glue contained in the separated water phase cannot be further processed, wasting materials, increasing the difficulty of wastewater treatment, decanting with a tray decanter or coalescer The device only reflects the function of separation, but fails to wash and purify the material, and does not further process the centrifuge coolant mixed with polycarbonate resin

[0006] Chinese patent CN1324375A describes the separation and washing method of a combination of a coalescing separator and a centrifuge or a full coalescing separator. In the separation and washing method of a combination of a coalescing separator and a centrifuge, a phase separation device, a coalescence Separator, one pump, three centrifuges, more dynamic equipment, which increases the difficulty of maintenance and the separated water phase is directly discharged without secondary separation, resulting in material loss

In the combination method of phase separation equipment and coalescence separator, at least 5 coalescence separators need to be used, and the separated materials all enter the previous separator, the separation efficiency is low, and it is difficult to guarantee the effect of washing and purification

[0007] Chinese patent CN1648153A also describes a separation and washing process combining static separation and coalescence separation, but because there is no high-efficiency mixing equipment, the material cannot be fully mixed with the washing liquid, and the washing and purification effect is poor. Ester glue, and no secondary extraction and separation, resulting in product loss

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