Flue gas low-temperature denitration and semi-dry desulfurization process

The invention relates to a flue gas low-temperature denitration and semi-dry desulfurization process, which comprises the following steps of (1) feeding tail gas into a low-temperature SCR (Selective Catalytic Reduction) reactor, and reducing NOx in the tail gas to be N2 and H2O; (2) feeding gas obtained in the step (1) into a semi-dry desulfurization reaction system, spraying an absorbing agent into the reaction system to desulfurize, and removing acid gas in the tail gas; (3) feeding gas obtained in the step (2) into a dust collection device, thoroughly removing dust in the tail gas, and discharging obtained cleaned gas into atmosphere. The tail gas comprises NOx, SO2, SO3, HCl and the like, and the tail gas temperature is 100 to 260 DEG C. The process provided by the invention can be widely applied to treating the tail gas containing the NOx and the SO2 produced by enterprises such as electric power, steel and petrochemical industry; after treatment, in the cleaned tail gas, the SO2 is less than or equal to 35mg/Nm , the NOx is less than or equal to 50mg/Nm ,and the dust is less than or equal to 5mg/Nm ; the conversion rate of the SO2 is larger than or equal to 97 percent, and the conversion rate of the NOx is larger than or equal to 85 percent.