Method for producing purified gas, and equipment for producing the same

An apparatus for producing a purified gas containing carbon dioxide gas, comprising:

• a first concentration device that produces an intermediate gas having a higher concentration of carbon dioxide gas than a target gas, wherein the first concentration device includes a first adsorption tower that adsorbs carbon dioxide gas in the target gas containing carbon dioxide gas by vacuum regeneration pressure swing adsorption;
• and
• a second concentration device that produces a purified gas having an even higher concentration of carbon dioxide gas than the intermediate gas, wherein the second concentration device includes a second adsorption tower that adsorbs carbon dioxide gas in the intermediate gas by vacuum regeneration pressure swing adsorption or pressure swing adsorption or a membrane separation device that selectively passes carbon dioxide gas in the intermediate gas.