In the fields of industrial production, energy monitoring, and safety protection, accurate analysis of gas composition is the core link to ensure process stability, improve energy efficiency, and prevent accidents. Portable gas analyzers have become an indispensable "mobile laboratory" in modern industrial testing due to their high precision, fast response, and flexible deployment characteristics. Its technology integrates multimodal sensing principles such as non dispersive infrared (NDIR), thermal conductivity (TCD), and electrochemistry, and achieves synchronous analysis of multi-component gases through intelligent algorithms, providing efficient solutions for on-site detection in industries such as steel, chemical, and new energy.

1、 Technical principle: Precise collaboration of multimodal sensing

The core of portable gas analyzer lies in its multi technology fusion detection system. For heterogeneous atomic molecules such as CO, CO ₂, and CH ₄, the instrument uses non dispersive infrared (NDIR) technology to quantitatively analyze the absorption characteristics of gas molecules towards specific wavelengths of infrared light. The infrared absorption peaks of CO in the 4.6 μ m wavelength band, CO ₂ in the 4.26 μ m wavelength band, and CH ₄ in the 3.3 μ m wavelength band are captured by an optical filter and a high-sensitivity detector to measure the attenuation of light intensity, and the gas concentration is calculated using the Lambert Beer law. This technology has advantages such as strong selectivity, long lifespan, and no need for consumables, making it particularly suitable for detecting oxygen deficient environments or complex mixed gases.

The detection of H ₂ relies on the principle of thermal conductivity (TCD). Due to the higher thermal conductivity of hydrogen gas compared to other gases, when a hydrogen containing mixed gas passes through a thermal conductivity cell, the temperature change of the resistance wire inside the cell will cause a change in the resistance value. This change is converted into an electrical signal through a bridge circuit, achieving accurate measurement of H ₂ concentration. TCD technology is independent of NDIR systems, avoiding cross interference and ensuring the independence of H ₂ detection.

For the monitoring of O ₂, some models use electrochemical sensors. Oxygen undergoes a reduction reaction at the working electrode of the sensor, generating a current signal proportional to its concentration, which is amplified and displayed as a numerical value. This technology has the characteristics of fast response and good linearity, but requires regular calibration to maintain accuracy.

The multi technology collaborative architecture enables the instrument to simultaneously analyze six gases including CO, CO ₂, CH ₄, H ₂, O ₂, and CnHm (hydrocarbons), covering the core components of coal gasification, biogas, urban gas, and other scenarios. In the coal gasification process, the ratio of CO to H ₂ in the outlet gas of the gasifier directly reflects the reaction efficiency, while the residual O ₂ may pose an explosion risk. The synchronous detection capability of portable analyzers provides key data support for process optimization and safety control.

2、 Guide to using portable gas analyzer: complete process from startup to data application

1. Pre inspection and calibration

Before starting up, it is necessary to check whether the sampling tube and filter are clean, and whether the battery is fully charged. When using for the first time or when there are significant changes in environmental temperature and humidity, zero point calibration is required: place the instrument in clean air, start the automatic calibration program, and complete initialization after the baseline is stable. For high-precision detection scenarios, it is recommended to use standard gas for range calibration, introduce 5% CO standard gas, and adjust the instrument reading to the range of 5.00 ± 0.05%.

2. Sampling and analysis

Select the sampling method based on the detection scenario:

Pipeline direct sampling: Insert the sampling tube deep into the center of the pipeline to avoid the influence of edge turbulence, and control the flow rate at 0.5-2L/min;

Diffusion sampling: suitable for open spaces, place the instrument within 1 meter of the leakage point and wait for the concentration reading to stabilize;

Pump suction sampling: using a built-in sampling pump to extract distant gas, suitable for narrow spaces or high-altitude operations.

After sampling is completed, the instrument automatically starts the analysis program and displays the concentration and calorific value (low calorific value and high calorific value) of the six components within 10-30 seconds.