Sorbent trap sampling presents inherent challenges, especially when environmental conditions are less than ideal. Whether faced with cold temperatures, high humidity, or excessive moisture in the stack, it is crucial to adopt a proactive approach to ensure accurate and reliable sampling results.
1. Ensure Proper Functionality of the Heated Umbilical
One of the most critical factors in colder conditions is ensuring that the heated umbilical line is functioning correctly. If the sample gas cools and condenses, it can lead to water bridging across the ¼” lines, which may cause high vacuum issues. This is particularly important in winter or wet conditions. Verifying that the heated umbilical is operational is essential to avoid such problems.
2. Pre-heat the Probe Before Installation
Before installing new sorbent traps, it is vital that the probe is adequately heated. If the probe remains cold during installation, even if a pre-leak check passes, material expansion during heating may result in leaks that cause a failed post-leak check. Ensuring the probe is warmed up before beginning the installation of traps is crucial for avoiding potential issues.
3. Monitor Moisture Knockouts and Gas Conditioners
Moisture knockouts and gas conditioners are integral in preventing excess moisture in the system, but they also require careful attention during colder weather. As temperatures drop, moisture in knockouts can freeze, causing blockages and high vacuum problems. Whether using collection bottles, peristaltic pumps, or cooling technologies such as Peltier cooling or refrigerant-based systems, it is imperative to ensure that cabinet heaters are functioning to maintain a stable temperature. This will help prevent freezing issues that may compromise system performance.
4. Wet Sorbent Traps and Their Impact on Analysis
Wet sorbent traps are a common issue, often caused by exposure to high-moisture stack conditions. While this may seem like a minor inconvenience, it can significantly disrupt analysis. For example, a failure in the temperature controller of a probe may result in moisture accumulation in the traps, which can then evaporate and condense inside the sample cell of the M324 analyzer. This can delay testing, require a full cleaning of the analyzer, and potentially necessitate recalibration.
Even a small amount of moisture can negatively impact analysis. Water entering the sample cell alters the baseline standard deviation, reducing the signal-to-noise ratio and diminishing sensitivity. This can lead to inaccurate results.
5. Prevent Moisture Entry in the M324 Sample Flow Path
In environments with moderate moisture, water may make its way into the sample flow path through the tubing, leading to condensation inside the sample cell. To mitigate this, it is recommended to kink or disconnect the lines during cleaning procedures to prevent moisture from entering critical components of the system.
6. Longer Traps to Improve Moisture Management
For those experiencing frequent moisture entrainment, using sorbent traps with extended lengths such as 450 mm is an effective solution. Longer traps provide more surface area for moisture to evaporate as the trap heats up, improving moisture management and reducing the likelihood of interference with analysis.
Conclusion: Proactive Measures for Consistent Sampling
Regardless of environmental conditions, effective sorbent trap sampling requires thorough preparation and attention to detail. By ensuring the proper functioning of heated umbilical lines, maintaining proper probe temperatures, and managing moisture effectively, many common issues can be avoided. Taking these preventative steps can significantly enhance the accuracy and reliability of sampling, ensuring high-quality results regardless of the challenges posed by external conditions.
For additional guidance tailored to specific testing conditions, feel free to contact us. Our team of experts is available and happy to offer advice and practical pointers to help optimize sorbent trap sampling and ensure the best possible outcomes in any environment.
