The present invention provides a method for the treatment of mercury present
in exhaust gas wherein, after a chlorinating agent is added to exhaust gas containing
nitrogen oxides, sulfur oxides and mercury, the exhaust gas is subjected to a reductive
denitration treatment in the presence of a solid catalyst and then to wet desulfurization
using an alkaline absorbing fluid, the method being characterized by measuring
the mercury concentration in the exhaust gas after the wet desulfurization; calculating
a predicted value of the inlet mercury concentration before the reductive denitration
treatment on the basis of the measured mercury concentration; and controlling the
feed rate of the chlorinating agent added prior to the reductive denitration treatment,
according to the deviation of the predicted value from a reference inlet mercury
concentration, as well as a system for the treatment of exhaust gas. Thus, the
present invention provides an exhaust gas treatment process permitting the removal
of mercury, and this process makes it possible to achieve efficient operation of
the system and maintain the performance thereof without exerting any adverse influence
the units within the system.
