Polyethylene Furanoate Production from FDCA

The process under analysis comprises two major sections: (1) Melt-phase polymerization; and (2) Solid-state polymerization.

Melt-phase polymerization. MEG and FDCA are initially fed to the paste system which prepares, in batches, a uniform feed slurry for melt-polymerization downstream. The mixture then passes through two agitated and jacketed reactors, in which esterification takes place generating bis(2-hydroxyethyl)-2,5-furandicarboxylate (BHEF). The BHEF monomer is fed to an agitated, jacketed reactor. Here, vacuum and heat are applied for the removal of water and ethylene glycol, shifting the reaction equilibrium towards polymerization. Antimony glycolate is used as catalyst. This pre-polymerization generates PEF oligomers. In the polycondensation step, the PEF oligomers condensate, increasing the degree of polymerization. The reaction occurs at a rotating disc reactor under an even higher vacuum, removing water and excess MEG. Here, higher molecular weight PEF chains are generated, yielding a textile fiber-grade PEF. Gaseous effluents from all reactors are condensed and fed to a distillation column where MEG is recovered in the bottom and recirculated. The previous melt-phase polymerization is concluded by a Pelletizing step, in which the molten PEF is extruded, cooled, and chopped into cylindrical shapes. The amorphous PEF chips are screened, classified, dried and then conveyed to a silo.

Solid-state polymerization. The PEF chips are crystallized, to not stick together or agglomerate due to high polymerization temperatures downstream. The crystallized particles are then polycondensed in the SSP reactor, a long cylindrical hopper-type vessel. The bottle-grade PEF chips are fed to a fluidized-bed cooler, which cools down the PEF and removes dust. The PEF chips are homogenized and packed in bags.