Method for treating exhaust gas, and facility for carrying out method

An exhaust gas treatment facility comprising:

• a dust collection filter device;
• an exhaust gas line capable of introducing an exhaust gas containing an acid gas that contains carbon dioxide into the dust collection filter device;
• and
• a reactant supplier capable of supplying a reactant capable of reacting with carbon dioxide into the exhaust gas,
• wherein the dust collection filter device includes a case in which an inlet through which a gas flows in and an outlet through which a gas flows out are formed, and a dust collection filter that partitions an inside of the case into an inlet-side space on a side of the inlet and an outlet-side space on a side of the outlet and has heat resistance of 250° C. or higher,
• the exhaust gas line is connected to the inlet of the dust collection filter device, and
• the reactant supplier is capable of supplying the reactant into the exhaust gas line or into the inlet-side space.