Method and device for collaborative removal of mercury in flue gas

The invention discloses a method and device for the collaborative removal of mercury in flue gas, and belongs to the purification field of the flue gas in atmospheric pollutants of power plant boilers. The method comprises the following steps that: after primary hot air or secondary hot air of a temperature boiler is introduced to mix with a mercury removal oxidant and an SCR (selective catalytic reduction) denitration reductant, and then the flue gas is injected to mix again, an obtained mixture enters an SCR denitration device to denitrate along a flow path of the flue gas, and simultaneously, elemental mercury Hg0 is oxidated into gaseous bivalent mercury oxide Hg ; then, the gaseous bivalent mercury oxide Hg enters a dust remover to carry out dust removal, and simultaneously, granular mercury Hg is removed; and then, the obtained product is subjected to desulfurization in a wet flue gas desulfurization device, and simultaneously, the bivalent mercury oxide Hg is removed. The device comprises an SCR denitration system, and a device for mixing hot air, a mercury removal oxidant and the SCR denitration reductant. The method and the device for the collaborative removal of the mercury in the flue gas, disclosed by the invention, fully use the collaborative function of the existing SCR denitration system, the dust remover and the WFGD (wet flue gas desulfurization device), and are few in system changes and good in mercury removal effect.