Ultraviolet spectrum detection method and device for monitoring trace sulfur dioxide in blast furnace flue gas

The invention discloses an ultraviolet spectrum detection method and device for monitoring trace SO2 in blast furnace flue gas. The device comprises a light source (1), a spectroscope (9), a sample pool (2), a reference pool (3), a detector (4), an arithmetic unit (5) and a reflector (10). The incident light emitted by the light source (1) passes through the spectroscope (9) to be transmitted light and reflected light with the same light intensity, the transmitted light is incident to a mixed component in the sample pool 2; and the reflected light enters the reference pool (3) without the mixed component; the detector (4) detects the light intensity of the transmitted light and the reflected light; and the arithmetic unit (5) is used for carrying out differential treatment on the transmitted light intensity obtained by the detector (4) so as to obtain the gas component in the blast furnace flue gas. According to the method, the appropriate wavelength is selected for differential spectrum detection, and the in