Method for online monitoring of sulfur dioxide concentration in gas corrosion test box

Abstract

The invention discloses a method for online monitoring of sulfur dioxide concentration in a gas corrosion test box. The method comprises the following steps: (1) connecting an absorption bottle to theair outlet of a gas corrosion test box; (2) adding an absorbing liquid to the absorption bottle, and replacing the absorption bottle every 0.5 ~ 1 hour; (3) using the absorbing liquid replaced from the absorption bottle as a sample solution, filtering the sample solution and a blank solution through a 0.45 m microporous membrane, and sequentially injecting into an ion chromatograph for analysis;(4) filtering six groups of different concentrations of SO32- and SO42-mixed standard solution through a 0.45 m microporous membrane for ion chromatography analysis to determine the retention time andthe peak area of SO32- and SO42-, and drawing a standard curve; (5) calculating the content of SO32- and SO42- in the sample solution and the blank solution by a standard curve method, and combine the two as the content of SO2; and (6) expressing the SO2 by the mass of SO2 absorbed per liter of the solution.

Description

technical field [0001] The invention relates to a method for on-line monitoring of the concentration of corrosive gas in a sulfur dioxide gas corrosion test chamber by using a solution absorption method, in particular to a method for on-line monitoring of the concentration of sulfur dioxide in the gas corrosion test chamber. Background technique [0002] Gas corrosion test, especially SO 2 、H 2 The S gas corrosion test is an important test method for evaluating the corrosion resistance of metals, coated plates and other materials. At present, the concentration of corrosive gas in the gas corrosion test chamber is mainly calculated according to the pressure of the gas cylinder, the reading of the flow meter and the volume of the test chamber. This conversion is based on the assumption that "the gas cylinder pressure is a known constant" or "the gas cylinder pressure is a known linear change with time" and "the purity of the corrosive gas in the gas cylinder remains unchange...

AI Technical Summary

Problems solved by technology

However, since the pressure of the gas cylinder is a variable with the loss of gas in the cylinder, and the change of gas pressure is not a linear change with time, and it cannot be guaranteed that the purity of the corrosive gas in the gas cylinder will not change during the test, so There is a deviation between the converted concentration of corrosive gas in the test chamber and the actual concentration of corrosive gas in the test chamber

This deviation is particularly prominent in low-concentration (ppm level) gas corrosion tests, which will directly affect the judgment of technicians on the results of gas corrosion tests

Because it is difficult to obtain an accurate concentration of corrosive gas in the test chamber, it is difficult to accurately control the test time and test process

This problem has restricted the popularization and application of gas corrosion test methods in many industries such as automobiles, building materials, and coatings.

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