FLUE GAS PURIFYING DEVICE

摘要

A flue gas purifying device includes an exhaust pipe that guides flue gas discharged from an internal combustion engine; a catalytic unit that is arranged on a downstream side to the internal combustion engine in a flow direction of flue gas and includes a nitrogen-oxide storage-reduction catalyst that stores nitrogen oxides contained in flue gas and a support mechanism that is arranged in the exhaust pipe and supports the nitrogen-oxide storage-reduction catalyst in the exhaust pipe; a reducing-agent injecting unit that injects a reducing agent to the catalytic unit in the exhaust pipe; a concentration measuring unit that is arranged on a downstream side to the catalytic unit in the flow direction of flue gas and measures a concentration of nitrogen oxides in flue gas having passed through the nitrogen-oxide storage-reduction catalyst; and a control unit that controls whether to inject the reducing agent from the reducing-agent injecting unit based on a concentration of nitrogen oxides measured by the concentration measuring unit.