The hydrogen impurity analyzer is used to detect various impurity components in hydrogen gas, ensuring that the purity of hydrogen gas meets industrial application standards. Impurities may include moisture, oxygen, carbon monoxide, carbon dioxide, nitrogen, helium, etc. Common methods for impurity analysis in hydrogen include the following:
1. Gas chromatography (GC)
Principle: Gas chromatography is a commonly used gas analysis technique that utilizes the different distribution coefficients of gases to separate various components in gas samples.
Application: Suitable for detecting impurities such as oxygen, methane, carbon monoxide, and carbon dioxide in hydrogen gas.
Advantages: High sensitivity, good resolution, and the ability to quantitatively analyze various gas components.
Disadvantages: The operation is relatively complex and requires periodic maintenance.
2. Thermal conductivity cell method (TCD)
Principle: Thermal conductivity cell method is based on the difference in thermal conductivity of different gases to detect the concentration of different components in gas samples.
Application: Widely used for detecting moisture, nitrogen, and oxygen in hydrogen gas, especially suitable for detecting low concentration impurities.
Advantages: Simple equipment, low cost, real-time online monitoring, suitable for use in large-scale production.
Disadvantage: Low sensitivity to certain gases such as helium and hydrogen.
3. Infrared absorption method (NDIR)
Principle: Based on the absorption characteristics of different gases towards specific infrared wavelengths, the concentration of the gas is analyzed by measuring the absorption amount.
Application: Commonly used for detecting gases such as carbon dioxide and carbon monoxide in hydrogen gas.
Advantages: Fast analysis speed, high sensitivity, and suitable for online monitoring.
Disadvantage: It can only detect specific gases and requires relatively precise calibration.
4. Hydrogen specific sensor
Principle: By utilizing the electrochemical or semiconductor properties of hydrogen, an electrical signal is generated through the reaction between hydrogen and the sensor surface to measure hydrogen concentration.
Application: Mainly used for hydrogen concentration measurement and impurity detection, suitable for hydrogen production and storage fields.
Advantages: High sensitivity, fast response time, and relatively simple equipment, suitable for on-site use.
Disadvantage: Sensors may be affected by environmental factors such as temperature and humidity.
5. Mass spectrometry (MS)
Principle: Mass spectrometry can accurately measure impurities in hydrogen samples by ionizing gas molecules and analyzing them based on the mass charge ratio of the ions.
Application: Suitable for high-precision and high-sensitivity hydrogen impurity analysis, capable of detecting extremely low concentration impurities including helium, nitrogen, etc.
Advantages: High sensitivity, able to analyze various gas impurities, suitable for scientific research and high demand industrial applications.
Disadvantages: Expensive equipment and complex operation.
6. Electrochemical analysis method
Principle: By generating a current signal through chemical reactions on the electrode surface, impurities such as oxygen and carbon monoxide in hydrogen gas can be analyzed by measuring the changes in the signal.
Application: Suitable for detecting impurities such as oxygen and carbon dioxide in hydrogen gas.
Advantages: Simple equipment, low cost, easy operation, suitable for portable use.
Disadvantages: Sensitivity and selectivity may be low, and electrodes need to be replaced regularly.
7. Fourier Transform Infrared Spectroscopy (FTIR)
Principle: Transform the infrared spectral signal into easily analyzable data through Fourier transform for identifying and quantitatively analyzing gas components.
Application: Suitable for various impurity gases in hydrogen, including water, carbon dioxide, carbon monoxide, etc.
Advantages: High resolution, capable of detecting multiple gas components simultaneously.
Disadvantages: The equipment is relatively expensive and requires complex operations.
Summary:
Different impurity analysis methods have different advantages, disadvantages, and applicability. When choosing a hydrogen impurity analyzer, it is necessary to select the most suitable detection technology based on the actual application requirements (such as accuracy, real-time monitoring, cost, etc.). For high-precision applications, mass spectrometry and gas chromatography are common choices; For general industrial monitoring, thermal conductivity cell method and electrochemical sensors are more commonly used.