Desulfurization and denitrification purification device for flue gas in chimney

The invention relates to the technical field of flue gas purification, in particular to a desulfurization and denitrification purification device for flue gas in a chimney, which comprises a fixing device, a primary purification device, a secondary purification device and a cover plate which are stacked in the vertical direction, flue gas enters from the bottom end of the fixing device, passes through the primary purification device and the secondary purification device, and is discharged from the cover plate, a plurality of air outlet holes are formed in the cover plate; the fixing device comprises a base, at least six supporting rods, at least six limiting rods, nuts, limiting blocks, an auxiliary ring, a top block, blocking cloth and a fan, the base is of an annular structure, one end of each supporting rod is hinged to the annular outer wall of the base, and the number of the limiting rods is at least six; the fixing device is installed in the chimney, flue gas is desulfurized and denitrated in the smoke