Reasons for the Poisoning of Combustible Gas Detection Sensors and Protection Measures
Combustible gas detectors are commonly used safety protection instruments in the process industry. Currently, most of the detectors in use are catalytic combustion type combustible gas detectors. However, this type of detector has the phenomenon of catalytic element poisoning, which leads to the inability to perform its functions and poses a potential safety hazard. Therefore, it must be taken seriously. Today, let's follow Lanyue Measurement and Control to take a look at the causes of the poisoning of combustible gas detectors and the protection measures.
Causes of Poisoning
In the process industry, many chemical substances can be absorbed by the catalyst or react with the catalyst to form new compounds, thus inhibiting the catalytic reaction, even poisoning the catalytic element and causing its sensitivity to decline or even fail completely. When the sensor works in an environment with these chemical substances for a long time, the catalyst will be poisoned and deactivated, resulting in a significant decrease in the sensitivity of the catalytic element and shortening the lifespan of the element. The most common of these chemical substances are mainly two types: silicides and sulfides.
There are various reasons for the poisoning of combustible gas detection sensors. However, by selecting catalytic elements with strong anti-poisoning capabilities, installing filters, avoiding contact with harmful substances, reducing the exposure time, and following the installation and maintenance guidelines, the poisoning of sensors can be effectively prevented, ensuring their normal operation and the accuracy of monitoring. This is of great significance for preventing fire and explosion accidents and ensuring industrial safety.
1: Silicides
Silicides often exist in large quantities in compounds such as lubricating oils, cleaning agents, adhesives, and sealants, and are widely used in the petrochemical industry, which can significantly inhibit the response of the sensor. When the concentration of silicon compounds is in parts per million, the response degree of the sensor will decrease. Organosilicon will decompose the catalyst in a high-temperature environment and form a solid substance on the surface of the catalyst, resulting in a decrease in the sensitivity of the sensor. And organosilicon compounds at higher concentrations will immediately damage the gas detector.
2: Sulfides
Sulfides are easily oxidized into mineral acids, which corrode the catalytic element. In severe cases, it may even lead to the failure of the catalytic element. Hydrogen sulfide and many other sulfides may corrode the sensor when they are oxidized into inorganic acids. High-temperature organic acids (such as acetic acid), or direct exposure to acid vapors (such as hydrochloric acid vapor and sulfuric acid vapor) will also corrode the sensor in the same way.
