CEMS-based carbon dioxide online monitoring method and system

The invention belongs to the technical field of carbon emission calculation, and discloses a carbon dioxide online monitoring method and system based on a CEMS (continuous emission monitoring system), and the method comprises the steps: calculating the fuel element carbon content according to a fuel element carbon content fitting equation, and calculating the phased carbon emission of a unit in combination with the operation data of a unit fuel management system; calculating the carbon dioxide concentration of the dry flue gas of the fire coal according to the oxygen content, monitored by the CEMS, in the dry flue gas after combustion of the fire coal, and calculating the accumulated carbon emission in the data stage of the CEMS in combination with the operation parameters of the CEMS; fitting analysis is carried out on unit stage carbon emission and CEMS data stage accumulated carbon emission, and calibration factors are obtained; and correcting the real-time carbon emission based on the CEMS data of the uni