Liquid Sulfuric Acid Test Method Research

This topic is one of the major projects of national special instrument "ultra-low emission monitoring instrument for coal-fired power plants",which ma inly s tudies the quantitative monitoring technology of SO3 and sulfur ic acid mist.By consult ing related references,It is found that there are several commonly used methods to measure SO3 and sulfuric acid mist.It is difficult to realize on-line real-time monitoring by using the non-optical detection method with the reaction process is slow.While using infrared absorption spectroscopy method under the heating condit ion could lead to corrosion of the Infrared lens by sulfuric acid mist.Therefore,this paper mainly uses UV absorption spectroscopy to monitor air pollut ion.UV absorption spectroscopy is a commonly used spectroscopic analysis based on the absorption spectra generated by intra-molecular electron transitions.With advantages like high sensitivity,low detection limit and high energy,it has become a commonly used visible absorption spectroscopy.The paper mainly carried out the practice of finding a method to solve corrosion of the infrared window lens by sulfuric acid mist.In actual measurement of infrared absorption spectrum of sulfur ic acid mist under the heating condit ion,corrosion of the infrared window CaF2 lens by sulfur ic acid have a big impact on subsequent research work.So we choose several corrosion and high temperature resisted infrared window lens and coating layer to design experiments,and verify which kind of the lens and coating material can be used in high temperature and acid environment.Ultimately by comparing,we consider sapphire lens and boron nitride lens to be suitable as an infrared window.The practice of measuring ultraviolet absorption spectra of liquid sulphuric acid was carried out.Build ultraviolet spectrum measurement system,measure ultraviolet absorption spectrum of liquid sulfur ic acid with different concentration and kinds.of characteristics of ultraviolet absorption spectrum,and the law of qualitative and quantitative analys is of the spectral features.Q ualitatively and quantitatively analysis the law of spectral characteristic pattern.By the contrast analys is,the results show that the UV absorption of sulfur ic acid can be seen at the wavelength of 190-200 nm.When the liquid sulfuric acid concentration is less than 1.5%,the law of light transmission conforms to Beer-Lambert’s law.When the liquid sulfuric acid concentration is less than 0.05%,the peak of absorption spectra is linear with the concentration.This paper mainly carried out the practice of measuring the ultraviolet absorption spectra of the liquid nitric acid and reducing the detection limit for detecting the absorption spectra of liquid sulfuric acid.In the process of actual measurement,Because the oxygen in the air and coal pipe of nitrogen oxides in the exhaust from coal pipe and nitric acid will influence on the measurement of liquid sulfuric acid ultraviolet absorption spectrum,a ultraviolet spectrum measurement system was designed and built to eliminate oxygen interference.Using such measures can reduce the detection limit of the measurement to 0.2 PPM.Also can calculate the absorption cross section of liquid sulfuric acid in the ultraviolet area.And then the spectrum measurement system was used to measure liquid nitric acid ultraviolet absorption spectrum of regularity and analyzes the spectrum characteristic.