Method for preventing polymerization in thin-film type evaporating device

摘要

A method of effecting heat exchange on an easily polymerizable substance comprises supplying the distillate component at the vapor outlet to a recovering column disposed in the upper part of a thin-film type evaporating device and simultaneously, using at least part of the extracted liquid from a recovering column as the feed raw material. A method of effecting heat exchange on an easily polymerizable substance by supplying the distillate component at the vapor outlet to a recovering column disposed in the upper part of a thin-film type evaporating device (II) and simultaneously, using at least part of the extracted liquid from a recovering column as the feed raw material for (II), characterized by disposing a liquid sealing part utilizing the extracted liquid of the recovering column in the part of the pipe interconnecting the extract outlet of the recovering column and the thin-film type recovering device or supplying the extracted liquid of the recovering column under pressure to the thin-film type evaporating device. An independent claim is included for a method of preventing an easily polymerizable substance (I) from being polymerized in a thin-film type evaporating device (II) when supplying a solution of (I) to the evaporating heating surface of (II) by the centrifugal force of a stirring rotary shaft. The distilled vapor of (I) is mixed with a molecular oxygen containing gas (III) and the extracted liquid obtained from the bottom of the device or a solution (IV) having a lower viscosity than the extracted liquid is supplied to a feed raw material inlet thereby adjusting the quantity of a wetting liquid per unit length of the evaporating heating surfaces to 0.02-2 m 3>/mhr.