ONLINE DETECTION DEVICE AND METHOD FOR SULFUR TRIOXIDE CONTAINED IN FLUE GAS

摘要

An online detection device and method for sulfur trioxide contained in flue gas. The device comprises: a flue gas sampling unit (100); a gas-liquid separator used for condensing SO₃ contained in the flue gas from the flue gas sampling unit into sulfuric acid droplets to separate same from a gas phase; a gas phase detection unit used for measuring a gas phase flow from the gas-liquid separator; a first solution pot (212) used for providing an absorption liquid in the gas-liquid separator to mix the sulfuric acid droplets so as to form a mixed liquid; a liquid phase detection unit used for measuring the quality of the converted SO₃ contained in the mixed liquid from the gas-liquid separator; and a digital control unit (300) used for calculating the concentration of the SO₃ contained in the flue gas according to the detection results of the gas phase detection unit and the liquid phase detection unit. The method realizes the online measurement of SO₃ contained in the flue gas, conducts sampling on the SO₃ contained in flue gas and analyzes the content of SO₃, so as to facilitate a coal-fired power plant in taking corresponding measures to control the content of SO₃ contained in the flue gas, thereby reducing the corrosion of a flue pipe and a device thereof, and meanwhile minimizing the thermal loss from a boiler in smoke emission.