To restrain the occurrence of polymerization in a distillation column.
Distillation plates 10 are disposed in the distillation column 1 at appropriate intervals. A steam-mixed raw material (a) obtained by cracking naphtha is fed to the bottom of the column 1 from a naphtha cracker. The distillate component (b) is withdrawn from the top of the column 1 and sent to a quenching column. Fuel oil (c) is discharged from the bottom of the column 1. A support ring 11, a support beam 13 and a tray 14 of each of the plates 10 are made from a material having ≤10 μm surface roughness Ra. Since each of these members of the plates 10 has such smoothness, the liquid in the column 1 can flow on the plates 10 smoothly, the residence of the liquid on both sides of each of these members can be restrained to the utmost and polymerization can also be restrained. A heat exchanger 27, a magnet strainer 26 and other equipment are arranged on a circulation line 23 in the middle of the column 1 for removing iron content from the liquid passing through the strainer 26 by adsorption, so that the occurrence of the polymerization mainly caused by the iron content in the column 1 can be restrained.
HIROTO KENICHIRO
YAMANE KOYO
EBARA SEIJI
YASUDA KENTARO
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