A method of falling film melt polycondensation reaction between rows of tubes for preparing high-viscosity melt and its reactor

Abstract

The invention discloses relates to a row-up pipe film falling melt phase polycondensation method for preparing high-viscosity melt and a reactor thereof. The row-up pipe film falling melt phase polycondensation method is characterized in that melt monomer blend or pre-polymer forms waterfall-type film falling flow among row-up inter-pipe film falling support pipes to realize melt polycondensation, melt falls off the pipes and gathers to the bottom of the reactor for further stirring and uniformizing, and materials are discharged after reaction. The reactor used in this method is of integral vertical structure and comprises a shell, a heating medium tank at the upper end, inter-pipe film falling support pipes connected with the heating medium tank, a material tank, a bottom shell at the lower end, and a blender and so on. The film falling support pipes with inner pipes inside are vertically hung and rowed up, and orifices are communicated with the heating medium tank for flowing of the heating medium. The reactor has the advantages of low flowing resistance, no dead corners, large filming area, and fast surface upgrading, and plug flow is realized. Moreover, the reactor is applicable to melt polycondensation of high-viscosity melt such as PET.

Description

technical field [0001] The invention relates to a falling film type melt polycondensation reaction method and melt polycondensation reaction equipment in the production of high-viscosity polymers. Background technique [0002] The polycondensation reaction is a reversible equilibrium reaction. With the progress of the polycondensation reaction, small molecular compounds need to be removed from the reaction system in a timely and effective manner, so that the molecular weight of the polymer is continuously increased, including polyethylene terephthalate (PET), poly Polypropylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyamide (PA) and polycarbonate (PC), etc. The polymers are prepared by polycondensation reaction. The implementation methods of polycondensation reaction mainly include melt polycondensation, solid-state polycondensation, solution polycondensation, etc. Among them, melt polycondensation is widely used because of ...

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Problems solved by technology

The tube-plate tower reactor mainly relies on the design of internal components to make the molten material form a film on the surface structure of the tube or plate. Compared with the traditional horizontal stirring polycondensation reactor, its film-forming area and surface renewal frequency are higher, but its The built-in structure is complex, and it is easy to generate stagnation areas, resulting in melt degradation, and it is difficult to produce high-viscosity materials.

The falling film reactor outside the tube can make the material flow down in the form of a film along the outer surface of the tube. Since the material flows down naturally by gravity, there will be no clogging problem. This type of reactor has a relatively simple structure, a large mass transfer interface and a Uniform temperature and other advantages, but because the liquid film of the wall-attached free falling film flow presents a semi-parabolic velocity distribution from the inside to the outside, the surface velocity of the melt film is much higher than that of the area near the wall, and the residence time of the outer film is too short and the inside The film residence time is too long

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