METHOD FOR PRODUCING ETHYLENE OXIDE

A method for producing ethylene oxide (EO), said method comprising the steps of: supplying a reaction product gas that contains EO, which is produced by oxidizing ethylene by catalytic vapor-phase oxidation using molecular oxygen in the presence of a silver catalyst, to an EO absorption column to bring the reaction product gas into contact with an absorption solution that is supplied to the absorption column, and then supplying a column bottom part solution in the EO-containing absorption column to an EO purification system to purify EO in the purification system; and supplying at least a portion of a carbon dioxide gas-containing gas, which is discharged through a column top part of the absorption column, to a carbon dioxide gas absorption column to bring the carbon dioxide gas-containing gas into contact with an absorption solution, then withdrawing a carbon dioxide gas-rich absorption product solution, which is produced as the result of the contact, as a column bottom part solution in the absorption column, then supplying the carbon dioxide gas-rich absorption product solution to a top part of a carbon dioxide gas diffusion column to diffuse a carbon dioxide gas from the carbon dioxide gas-rich absorption product solution, and then discharging the diffused carbon dioxide gas through a column top part of the diffusion column as a discharged gas. The method is characterized in that the purification system is equipped with an EO purification column having a reboiler provided at the lower part thereof, and a heating medium for heating the reboiler is heated by means of heat exchange between the heating medium and the discharged gas.