| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preventing an apparatus for producing ethylene from fouling by which the optimal amount of a stable free radical compound to be added so as to suppress the polymerization and not to cause the fouling in the apparatus is determined from the total concentration of diene compounds in bottoms of a distillation column and process conditions in a separating and purifying step of the apparatus for producing the ethylene. SOLUTION: This method for preventing the apparatus for producing the ethylene from fouling comprises adding the stable free radical compound in an amount within the range higher than [D] determined by the formula, [D]= 3.5+5[exp(0.07T)]×C×(V/L)×10-6}/F wherein [D] denotes the amount (μ.mol/kg amount of fed raw material oil) of the stable free radical compound added to the amount of the oil fed to the distillation column; F denotes the functionality of the stable free radical compound, i.e. the number of radical sites in one molecule of the stable free radical compound; T denotes the column bottom temperature ( deg.C) of the distillation column; C denotes the total concentration (wt.%) of 1,3-butadiene, isoprene and cyclopentadiene in the bottoms of the distillation column; V denotes the volume (m3) of the column bottom of the distillation column; L denotes the flow rate (m3/min) taken out of the column bottom of the distillation column} and lower than [D] +3.5 to the amount of oil fed to the distillation column.
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