Studies On Miniemulsion Polymerization In Taylor Reactor

Process intensification is an important way to fulfill safety, green and high-efficiency in chemical process. Process intensification is one kind of chemical new technology to reduce volumes of equipments, shorten processes or increase the production, decrease the consumption of energy. Process intensification of reaction can be fulfilled by optimizing reactors to improve heat transfer and mass transfer during reaction. Improvement of momentum transfer is the foundation of improving heat and mass transfer, in other words, to improve flow fields firstly. Taylor reactor is one kind of reactors with special flow fields.As emulsion and mini-emulsion polymerization in Taylor reactor, some researchers found obvious process intensification phenomena, but some other researchers didn't find process intensification. In this paper, this problem was further identified and the mechanism was discussed.From the dimension of cold-model, the characters of resident time distribution in Taylor reactor in homogeneous system were investigated at first. The effects of Ta and Re on resident time distribution of fluids in Taylor reactor were further testified. The adjustability of resident time distribution through Ta and Re was testified. When fluids with high viscosity were used in Taylor reactor, the rules got from pure water fluid in other research weren't fit very well. The rules should be emended by viscosity. Second, Taylor vortex's effect on droplet size distribution of (mini-)emulsion in heterogeneous system was studied. Taylor vortex could reduce the average size of emulsion droplets, contrasted with stirring reactor. Taylor vortex's effect on mini-emulsion droplets was very special. It could induce size distribution to gradually become wider and eventually generate two peaks. This has strong relations with the flow field of Taylor vortex and definitely has obvious effects of polymerization.The studies of polymerization in Taylor reactor started with batch mini-emulsion polymerization compared with normal stirring tank reactor. As Ta is very high and the extent of turbulence in Taylor reactor is very high, the results in Taylor reactor were similar to that in stirring tank. But the decrease of particle size caused by homogeneous nucleation in Taylor reactor was more than that in stirring tank. This also implies the intensification of mass transfer between two phases in Taylor vortex. Next, continuous mini-emulsion polymerization in Taylor reactor was studied and compared with CSTR. When initiated by monomer-soluble initiator (AIBN), the process intensification was very dramatic. The conversion was much higher than that in CSTR. This result was mainly caused by the generation of two peaks of droplets. In the process of polymerization, the existence of polymers in particles blocks the coagulation of particles, so only smaller particles generate. This dramatically increases the total particle number and accelerates the polymerization rate. When initiated by water-soluble initiator (KPS), the process intensification was not very strong. But as the effect of Tanks-in-Series caused by resident time distribution, the conversion was still higher than CSTR. The reason is that the polarization of droplets and radical transfer from water phase to droplets intrigue a kind of mechanism similar to emulsion polymerization. The mechanism weakens the advantages of polarization of droplets and process intensification, too. At last, continuous emulsion polymerization in Taylor reactor was studied in the first step and no obvious process intensification was found.