Measurement of high concentration sulfur dioxide SO2 concentration

Determination method of high concentration sulfur dioxide in gas 1. Determination purpose The sulfur dioxide content at the reactor outlet of the dimethyl ether pilot plant directly affects the selection of the sulfur dioxide reuse plan and the preparation of the feasibility report. By observing the changes in the sulfur dioxide concentration under quantitative conditions, it can be used as a basis for completely judging whether the reaction between methane and sulfur trioxide is good or bad. 2. Method summary: Use sodium hydroxide solution of known concentration to absorb sulfur dioxide gas. Measure the remaining gas volume and titrate the remaining alkali solution with sulfuric acid solution to calculate the sulfur dioxide content. 3. Reagents and solutions 1. 0.5mol/L NaOH standard solution ； 2. 0.5mol/L H2SO4 standard solution ； 3. 1% phenolphthalein indicator. 4. Instrument: A set of pipe-type high-concentration gas measuring instrument, see Figure 1: Pipe-type high-concentration sulfur dioxide measuring device 5. Measurement preparation Use a clean bladder to absorb high-concentration sulfur dioxide gas, leave it for several hours or overnight to allow the reaction between the gas and the bladder to fully proceed, and then discharge the gas for later use. 6. Determination procedure 1. Wash the pipe absorber with neutral water and add 20ml of 0.5mol/L NaOH standard solution. Use a small amount of neutral water to rinse the sodium hydroxide on the pipe wall (another effect is to make the alkali solution slightly dilute). Add 3-5 drops of 1% phenolphthalein indicator to fill the trachea with the sodium hydroxide solution without any bubbles. The volume of the solution contained shall not exceed 1/3 of the total volume of the pipe. 2. Absorb and connect the deflation tube to the bladder, empty it a little in the fume hood and then clamp it. Immediately insert the air nozzle into the sodium hydroxide solution, align it with the lower opening of the trachea, and deflate the air until the air flow speed is 2-3 bubbles per second. When 2/3 of the tracheal solution changes color and the residual gas volume can be seen, ventilation is stopped. Remove the bladder and read the residual air volume (the trachea should be vertical when reading). Then wash the vent tube with neutral water. Use 0.5 or 0.1 mol/L H2SO4 standard solution to drip back excess sodium hydroxide and read the acid consumption. 7. Calculate sulfur dioxide (%) = (V1×C1-V2×C2)×10.945 __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ×100 (V1×C1-V2×C2)×10.945+V×273/(273+t) where V1×C1——the number of milliliters of sodium hydroxide solution added and the concentration of the substance ； V2×C2——The number of milliliters of sulfuric acid solution and the concentration of the substance used in the back-drip of sodium hydroxide solution ； 10.945——The volume of millimolar mass of sulfur dioxide, milliliters ； V——Residual gas volume, milliliters ； t——Room temperature at the time of measurement, °C.

2# bdsp001 First of all, thank you for your participation, but I think this method has limitations. It can only measure the SO2 concentration of one layer of conversion. The SO2 concentration of the remaining parts is greatly affected by SO3, so the accuracy of the results is not very high.

For other parts, test data can be obtained according to the iodometric method.

So how should we test the furnace outlet before purification, or the electrostatic precipitator area? These areas should all contain SO3 4# bdsp001

For the interference of sulfur trioxide, you can absorb sulfur trioxide with water before testing the instrument and then analyze the sulfur dioxide content.