MONOMER ELIMINATION IN SOLID PHASE POLYMERIZATION

PURPOSE:To readily eliminate monomers unreacted in a solid phase polymerization through the lower end of the chillers, by alternate changeover of two double-pipe chillers with fin for cooling the chillers after changeover to melt the monomers solidified within said chillers. CONSTITUTION:First, a granular polymer is fed to a polymerizer to carry out solid phase polymerization in a heated inert gas atmosphere. Thence, the impurity-contg. inert gas from the polymerizer is cooled in one (6a) of two parallel vertically installed double-pipe chillers with fin followed by eliminating the impurities in the adsorption column to bring said gas into recycling use. Along with this, when the chillers 6a clogged due to the solidification of the monomers unreacted caused by fall of temperature, changeover values 8a, 8b, 9a and 9b are switched to the other chiller 6b to continue the operation, as well as heating the chiller 6a clogged to melt the monomers solidified followed by discharge through the lower end of said chiller 6a by opening the stop valve 10a.