MANUFACTURING METHOD FOR LACTIDE USING A TUBE BUNDLE FALLING FILM REACTOR AND AN AGITATED THIN FILM REACTOR

摘要

The present invention relates to a lactide manufacturing method comprising: an evaporation concentration step (step 1) of a lactic acid aqueous solution, an oligomerization step (step 2) of lactic acids and a depolymerization step (step 3) of lactic acid oligomers. The step 2 is performed in a tube bundle falling film reactor. And the step 3 is performed in the tube bundle falling film reactor and an agitated thin film reactor in order. The present invention allows liquid phase reactants with high viscosity to be evenly distributed to each vertical tube of the tube bundle falling film reactor even at low pressure, is capable of continuously manufacturing lactide at high yield and high efficiency by applying the tube bundle falling film reactor running down only inner wall of the vertical tube in a circumferential direction in a uniform thickness to the whole unit processes and prevents the deposition of carbonic materials during long term operation by sequentially performing a depolymerization process in the tube bundle falling film reactor and the agitated thin film reactor, thereby having excellent process efficiency and economical feasibility since an operation stop period is increased in order to perform device washing.