Method and device for measuring sulfur trioxide in isopropanol solution by switching ion chromatography valve

Abstract

The invention relates to a device for measuring sulfur trioxide in an isopropanol solution by switching an ion chromatography valve. The device comprises a first pump, a second pump, a six-way valve I, a six-way valve II, a protection column, an analysis column, an inhibitor, a conductivity detector, an enrichment column, a trapping column, a quantitative loop, a sample injector and a waste liquidbottle; the second pump is connected with a point C of the six-way valve I through the trapping column; the quantitative loop is connected with a point D and a point A of the six-way valve I; the sample injector is connected with a point E of the six-way valve I, and a point F of the six-way valve I is connected with the waste liquid bottle; the first pump is connected with a point C of the six-way valve II; the enrichment column is connected with a point D and a point A of the six-way valve II, and a point E of the six-way valve II is connected with the waste liquid bottle. The device has the beneficial effects that 80% isopropanol absorption liquid is adopted to convert SO3 in a sample into SO4 < 2-> so as to inhibit the dissolution and oxidation of SO2 in the solution, so that the influence of SO2 on a determination result is reduced, and the influence of high-concentration isopropanol on the determination of SO4 < 2-> can be removed by virtue of a valve switching online pretreatment method.

Description

technical field [0001] The invention relates to a detection device for sulfur trioxide in flue gas, in particular to a method and a device for detecting sulfur trioxide in isopropanol solution by switching an ion chromatographic valve. Background technique [0002] The tail gas of thermal power plants contains soot, SO x , NO x , mercury and its compounds. Most of the sulfur oxides in flue gas are sulfur dioxide (SO 2 ), which has some SO 2 will be oxidized to SO 3 . SO 3 It is an extremely hygroscopic substance. The sulfuric acid mist formed after moisture absorption will adhere to the boiler equipment and the downstream equipment of the SCR system, and the formed H 2 SO 4 Will also be with NH 3 The reaction produces ammonium bisulfate [(NH 4 )HSO 4 ] and ammonium sulfate [(NH 4 ) 2 SO 4 ], will cause corrosion of pipelines, equipment and chimneys, resulting in opaque smoke exhaust, and SO 3 Discharged into the atmosphere will not only lead to smog and acid r...

AI Technical Summary

Problems solved by technology

Xiao Yuting and others used the precipitation titration method to determine SO in the flue gas of coal-fired power plants 3 There are certain limitations, there is a high concentration of SO in the flue gas 2 , in the presence of water vapor and high temperature, it is easy to oxidize and absorb water to form H 2 SO 3 , so that the measurement result is high, and the SO in the flue gas 3 The concentration is very low, and a small measurement error in the process of precipitation titration will bring a large relative error

Wang Jinxiu et al. used ultraviolet absorption spectroscopy to monitor SO in coal-fired power plants online 3 , the ultraviolet light beam that emits a specific spectrum penetrates the flue gas pool to be tested, and is detected according to the difference in the degree of light absorption by the flue gas, SO 3 with SO 2 There is a certain overlap in the absorption spectrum, the actual operation is due to the SO 2 Concentrations are much higher than SO 3 Concentration, and SO 3 It will combine with water molecules to form sulfuric acid and cannot be detected. This method has a great impact on the detection results

Huang Meifen and others used the hydrogen peroxide-barium chloride-thorium reagent method and the 80% isopropanol-barium chloride-thorium reagent method to absorb and simultaneously measure SO in flue gas. 2 and SO 3 concentration, not only the titration takes a long time but also has errors, and the amount of the indicator and the acidity of the solution will affect the test results, and the accuracy of the test results will be greatly reduced.

Images