Misstep in Industrial Gas Detector Selection: Misclassifying Organic Gases as Combustible Gases for Detection
Analysis: Most combustible gas detectors on the market use the principle of catalytic combustion. The principle of catalytic combustion is to use combustible gases to generate low-temperature flameless combustion on detection components with catalytic performance. The heat of combustion causes the temperature of the components to rise, thereby increasing the resistance value of the components. The change in resistance value is detected by a Wheatstone bridge to achieve the purpose of detecting the concentration of combustible gases.
Although in principle, as long as it can burn and release heat, it can be detected, people often say that catalytic combustion sensors can theoretically measure any combustible gas.
However, catalytic combustion sensors are not suitable for measuring long-chain alkanes, such as high flash point gasoline, diesel, aromatic hydrocarbons, etc. Compounds with more than 5 carbon atoms, such as benzene, toluene, and xylene, especially hydrocarbon compounds with benzene ring structures, have strong carbon chains that are difficult to break during catalytic combustion, resulting in incomplete combustion. Unburned molecules will accumulate on the surface of the catalytic beads, leading to the occurrence of "carbon deposition" phenomenon and hindering the subsequent combustion of other molecules. When carbon deposition reaches a certain level, combustible gas will not be able to effectively contact the catalytic beads, resulting in insensitive or even unresponsive detection. This is determined by the properties of the sensor itself and belongs to a selection error in the early stage.
Conclusion: Common organic volatile gases such as benzene, alcohols, lipids, and amines are not suitable for detection using catalytic combustion principles, and PID photoionization principles should be used for detection. Before purchasing a gas detector, it is important to consult with the product company to avoid similar errors.
Misunderstanding: Changing the usage environment without authorization
Analysis: The gas detector is designed to measure gas concentration values in the environment, and online measurement of hydrogen sulfide concentration in pipelines belongs to changing the usage environment. The sensor of the hydrogen sulfide gas detector is based on the electrochemical principle, and the degree of electrolyte loss is positively correlated with the concentration of hydrogen sulfide in the environment. The more hydrogen sulfide content there is, the faster the electrolyte consumption and the shorter the lifespan. In a normal environment, the concentration of hydrogen sulfide is 0, and only leakage consumes electrolyte, so the lifespan can reach 1-2 years. There is always hydrogen sulfide in the pipeline, and the electrolyte is constantly consumed, greatly reducing its natural lifespan.
