Fig 4. UGLD Gas Detectors
REDUCING RISK IN PETROCHEMICAL PLANTS WITH NEXT-GEN SAFETY TECHNOLOGIES
While the dangers and consequences of undetected hazardous gases in the petrochemical industries are well known by process and plant engineers, it doesn’t make protecting our talented people, sophisticated equipment and hard-working plants any easier. The consequences of a major accident caused by an unexpected hazard or unforeseen incident can still be devastating—especially when there is the loss of human life.
The technologies responsible for the latest generation of highly intelligent, effective gas monitoring equipment continue to advance in a number of areas. The objective is to make gas safety as effective, reliable, low maintenance and economical as possible. For that reason alone, the safety industry continuously innovates and focuses on developing new technologies, advanced materials and construction techniques (Fig 1).
So, we keep going and that is why it’s important for all of us to discuss the latest technological advances available today to everyone responsible for safety. In the safety arena, there are lots of changes and improvements that require process and plant engineers to spend considerable time staying up-to-date. For example, great strides in even the past one to three years are now being made in adopting and implementing the latest digital technologies.
The challenges
Plant teams generally express three concerns about fixed gas detection equipment: • Frequent sensor replacements • Installation and maintenance challenges • Integration with plant control systems
Under the best of circumstances, fixed combustible and toxic gas detection are difficult. Petrochemical processing plants are typically large and often have high-density layouts of tightly placed equipment, piping and tanks. Processing areas that require gas detection are often partially or fully exposed to the outdoors, subjecting gas monitors to heat, humidity, fog, rain and wind.
For these reasons, no single gas sensing technology is appropriate for all applications or situations or geographic location. Depending on the individual plant site, the surrounding environment and the nature of the leak source, a gas sensing technology that is appropriate in one place may not be appropriate in another. The differing chemistry of gases further complicates the detection method. For example, differences in density affect where a gas will pool inside a building or how a large cloud will move in the wind require a comprehensive approach.
Evolving gas sensor technologies
Compared to only 20 to 30 years ago, the most recent advances in fixed gas sensing technologies have led to more reliable and efficient plant safety monitoring systems. This includes all the major sensor technologies from all the safety industry suppliers, including electrochemical cells, catalytic bead, metal oxide semiconductor (MOS), infrared sensors and newer less well-known sensor technologies.
As effective as fixed-point gas sensors are, they still have one limitation: there is always the real possibility that leaking gas may not reach the gas sensors in sufficient concentration and in enough time to prevent a serious incident or accident. In general, the faster a gas sensing technology can detect a leak the quicker the safety system can respond and help to prevent a potential accident for a safer workplace.
This long-understood reality is leading to a new “layered” gas detection strategy for safety. This strategy begins with conventional fixed-point gas detectors and adds additional layers of newer gas sensing technologies such as ultrasonic gas leak detection (UGLD) and enhanced laser diode spectroscopy (ELDS) to provide more comprehensive protection.
technology with improved capabilities combined with intelligent features now includes non-intrusive touch button operation, better visual displays, extended calibration cycles, Bluetooth® wireless communication and multiple sensor capability (Fig 2).
These newer improved technologies now available with electrochemical sensors, for example, can expand calibration cycles up to 18 months (local calibration respected). Electrical pulse monitoring multiple times a day diagnostically determines the operational status of sensors in response to the effects of humidity, temperature, or pressure so they can automatically adjust themselves. When manual calibration is required, or sensor replacement is necessary, plant engineers are notified in time to complete the needed maintenance tasks without service interruption.
There are even some sensors that can warn if the sensor opening has become blocked and unable to detect a gas leak. By employing an acoustic mechanical design and algorithms, sound is measured
Electrochemical cells
The industry’s newest generation of fixed point electrochemical cell gas detection sensors has taken a giant step forward in the past 18 months. Electrochemical sensor
Fig 1. Risk Mitigation Scales Chart
OCTOBER / NOVEMBER •
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