Theoretical And Experimental Study On The Determination Of SO₃ Concentration By Spectrophotometry

The selective catalytic reduction of NO_X with NH₃ is the most efficient and widely used technology for removing NO_X from stationary power station at present.However,the wide use of catalysts,in particular SO₃ produced through the oxidation of SO₂,will cause corrosion problems,health problem,and reduced boiler performance.But SO₃ is hard to be measured accurately.The problem is so serious that the study on SO₃ measurement is imperative.In this paper,isopropanol absorption method is used as the SO₃/H₂SO₄ Capture method.Compared with the traditional control condensation method,this method is easy to operate and has strong practicability.The flue gas is fully heated in the sampling gun,and then the flue gas is added into the isopropanol absorption liquid to absorb the SO₃/H₂SO₄.It can capture SO₃/H₂SO₄ and reduce the effect of SO₂ on the result to the maximum extent.spectrophotometry was used to detect the content of the collected SO₃/H₂SO₄.The principle test of barium chloranilate spectrophotometric method is carried out.The best reaction time of this method was studied.The maximum absorption wavelength of SO₃/H₂SO₄ solution was obtained.The standard curve was obtained,and the reliability of the method was analyzed.The actual sampling analysis is carried out in the power plant,and the accurate data result is obtained.The feasibility of online monitoring of SO₃ concentration based on spectrophotometry was studied.A set of SO₃ detection device was designed under laboratory conditions,including gas liquid mixing and separation device,chemical reaction and filtration device and photoelectric detection module.The influence of the size of the reaction bed,the height of the liquid level and the amount of the drug on the measurement results was experimentally studied on the sensitivity and accurac y of the device testing.Show the advantages compared with the double light path detection system for single beam detection system,explores the influence of laser intensity and mirror angle on the measurement results.SO₃ online monitoring is still in the laboratory research stage,and there are still a lot of difficulties to be solved.