Analytical method for smoke analyzer

Flue gas analyzer In today's society, the environmental monitoring department has become an indispensable analytical instrument. It is widely used in petroleum, chemical fertilizer, cement, metallurgy, thermal power plant, CEMS, etc. The analysis principle using different flue gas analyzers may be different, and a comparison of several flue gas analysis methods is now made.

The traditional smoke analysis method, Austrian Gas Analysis Instrument Method, uses different solutions to successively absorb different components in a gas sample: absorb carbon dioxide in the sample with 40% sodium hydroxide; use potassium pyrolysate solution Absorb the oxygen in the sample; use ammoniacal cuprous chloride solution to absorb the carbon monoxide in the sample. The content of each component is then calculated based on the change in volume of the sample before and after absorption.

The Oxygen gas analyzer is simple enough. Although the cost of one-time acquisition is low but the long-term operating cost is high, the cost of analysts is removed, and only reagents and glassware are purchased at least 10,000 yuan per year, and the smoke must be sampled manually. Laboratory analysis, where analysts' operating skills and "attitude" have a great influence on the accuracy of the analysis. Oxygen gas analyzers can only perform single-component detection and analysis without multiple input and signal processing functions. The analysis is time-consuming, the operation is cumbersome, the response speed is slow, and the efficiency is low. It is difficult to analyze production conditions in real time. It is gradually being replaced by fully automatic analytical instruments.

The chromatographic method uses a column to inject a sample so that all components of the flue gas—oxygen, nitrogen, carbon monoxide, and carbon dioxide—are separated and detected by a detector and recorder. The whole analysis process is then recorded, and each area is then normalized to calculate each The content of the components. Chromatography provides high separation efficiency, low sample usage, multi-component analysis, high analytical accuracy, and long calibration cycles. However, the high price and high quality of the sample require high quality of the operator. Therefore, it is generally unbearable for small plants.

Infrared analysis method is simple and feasible. Its working principle is based on the selective absorption of certain gases to different wavelengths of infrared radiation, and the degree of absorption depends on the concentration of the gas being measured. For different molecular compounds, each molecule can only absorb infrared radiation energy of a certain wavelength range, that is, each molecule compound has one or several specific absorption frequencies, which are called characteristic frequencies. CO and CO have fixed characteristic frequencies, so the CO and CO content in the flue gas can be easily detected. Infrared analyzer also has the following advantages: 1 good selectivity. For multi-component mixed gases, no matter how the concentration of interfering components in the background gas changes, it only responds to the concentration of the measured components; 2 wide range of analysis; 3 short analysis cycle, fast response time; 4 can be measured simultaneously Several components. However, it is not suitable for analyzing non-polar diatomic molecules and monoatomic molecular gases in symmetric structures.