Column treating process and apparatus thereof

A distillation process for an easily polymerizable compound in a distillation column, fluid circulating route and filtrating device, wherein the distillation column comprises a lower portion and an upper portion, an inlet for introducing a fluid to the distillation column, and a taking out outlet for taking a portion of the fluid after treatment out from the upper portion of the distillation column, wherein the fluid circulating route is in communication with the lower portion of the distillation column, wherein the fluid circulating route draws fluid from one part of the lower portion of the distillation column and returns said fluid, from which solid impurities have been removed, to another part of the lower portion of the distillation column, and wherein the filtrating device is in the fluid circulating route, wherein the distillation process comprises the steps of:

• a) purifying the fluid in the distillation column, wherein the fluid comprises an easily polymerizable compound, wherein the easily polymerizable compound is (meth)acrylic acid or (meth)acrylic acid ester, wherein the fluid that has been purified is taken out from said taking out outlet or is drawn out from said one part of the lower portion of the distillation column;
• b) drawing out a fluid portion including solid impurities directly from said one part of the lower portion of the distillation column into the fluid circulating route, wherein the solid impurities comprise polymers formed in the distillation column by a polymerization of the easily polymerizable compound;
• c) removing solid impurities, including polymers formed in the distillation column by a polymerization of the easily polymerizable compound, from said fluid portion in the fluid circulating route with the filtrating device;
• d) returning said fluid portion, from which said solid impurities have been removed, via the fluid circulating route back to said another part of the lower portion of the distillation column;
• and
• e) conducting the steps of purifying, drawing, removing and returning continuously.