Petrochemical production, storage, and transportation create complex safety-critical working environments, with even more complex gas detection requirements and the need for fast VOC detection.
These safety-critical situations present serious demands to site operators as fast, accurate, and reliable gas detection helps protect the plant, equipment, revenue streams, and more importantly the workforce.
To maintain maximum plant and workforce safety, rapid detector response with accurate measurement and total detector reliability is key. That’s why astute plant operators choose Ion Science advanced patented Fence Electrode technology when evaluating and specifying VOC gas detection instrumentation.
One critical reason for this is the understanding that conventional photoionization (PID) technologies become increasingly inaccurate when subjected to contamination and relative humidity (RH). Although humidity is not just restricted to regions of the world where the high ambient humidity is a known issue, it can frequently be caused by such events as calibration of an instrument in an air-conditioned environment such as a site office before use outside in ambient temperatures.
This error can create considerable site safety hazards as under these circumstances’ measurements without Ion Science Fence Electrode Technology will become inaccurate at values of around 60% error at ≥90% relative humidity (RH). This can lead to significant danger when measuring or detecting solvents, fuels, chlorinated degreasers, benzene, and heat or transfer fluids for example, or when monitoring some inorganic vapors such as ammonia and hydrogen sulfide.
To mitigate error due to humidity, our competitors developed a range of humidity compensation tactics. These include fitting humidity sensors to the PID and using sensor data to provide a compensating algorithm, or using desiccant tubes placed in the sensor inlet to dry the gas stream, or humidifying the calibration gas by running it through a Nafion tube to equilibrate it with the ambient air humidity.
Generally, these workarounds have a poor effect on accuracy and reliability. They can significantly slow measurement response and clear-down times, which is a fast-unfolding petrochemical plant situation, which can cause a routine situation to become a hazardous one very quickly.