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Flue gas analyzers have become essential analytical instruments in the industrial and environmental monitoring sectors of today’s society. They are widely used in industries such as petroleum, fertilizers, cement, metallurgy, thermal power plants, and CEMS, and are attracting increasing attention. Different flue gas analyzers may employ different analysis principles; here is a comparison of several flue gas analysis methods. The traditional method for flue gas analysis, namely the Orsat gas analysis instrument method, involves using different solutions to sequentially absorb various components in the gas sample: 40% sodium hydroxide is used to absorb carbon dioxide from the sample ； Absorb oxygen from the sample using a potassium pyrogallate solution ； An ammoniacal copper(II) chloride solution is used to absorb carbon monoxide in the sample. Then, the content of each component is calculated based on the change in the volume of the sample before and after absorption. The Austen gas analyzer is relatively simple; although its initial cost of purchase is low, its long-term operating costs are high. Excluding the cost of analysts, just the expense for reagents and glassware each year amounts to over 10,000 yuan. Moreover, it is necessary to manually sample the flue gas for analysis in the laboratory, and the operational skills and \"attitude\" of the analysts have a significant impact on the accuracy of the analyses. The Austen gas analyzer can only conduct detection and analysis for each component individually; it lacks the capabilities for multiple inputs and signal processing. As a result, the analysis is time-consuming, the operation is complicated, the response speed is slow, and the efficiency is low, making it difficult to analyze production conditions in real time. It is now gradually being replaced by fully automatic analytical instruments. Chromatographic analysis involves using a chromatography column with a single injection to separate all components in flue gas—oxygen, nitrogen, carbon monoxide, carbon dioxide—allowing the entire analysis process to be measured and recorded by a detector and recorder. The concentration of each component is then calculated through area normalization. Chromatography features high separation efficiency, low sample consumption, the ability to analyze multiple components, high analytical precision, and a long calibration period. However, the prices are high, the quality requirements for samples are stringent, and the skills required of operators are also high; as a result, it is difficult for small factories to afford this. Infrared analysis is simple and feasible. Its working principle is based on the property that certain gases selectively absorb infrared radiation of different wavelengths, with the degree of absorption depending on the concentration of the gas being measured. For different molecular compounds, each molecule can absorb infrared radiation within only a certain wavelength range; in other words, each molecular compound has one or several specific absorption frequencies, known as characteristic frequencies. CO and CO have their fixed characteristic frequencies, so the concentrations of CO and CO in flue gas can be easily detected. Infrared analyzers also have the following advantages: ① Good selectivity. For multi-component mixed gases, regardless of how the concentrations of interfering components in the background gas change, it only responds to the concentration of the component being measured ； ②Broad analysis scope ； ③Short analysis cycle and fast response time ； ④Several components can be measured simultaneously. However, it is not applicable to the analysis of symmetrically structured nonpolar diatomic and monatomic molecular gases. This post was last edited by Mobei Yihai on 2009-4-5 12:43.]