Continuous Emissions Monitoring


To protect the environment and reduce health issues for their citizens, government regulators around the world aim to limit the emission of harmful air pollutants, such as hydrogen chloride (HCl), hydrofluoric acid (HF), hydrogen sulfide (H2S) and ammonia (NH3), from power generation and industrial processes. The most recent targets of tighter HCl regulations in the US are coal-fired power plants and Portland cement plants. These plants now find that advanced spectroscopic gas analyzers can play an important role in ensuring compliance with new limits on HCl emissions in a simple and cost-efficient manner.

With their high precision, great sensitivity and freedom from cross-interference, Tiger Optics’ Cavity Ring-Down Spectroscopy (CRDS) analyzers are ideal analytical solutions to monitor such pollutants without interference from moisture, ozone, oxygen, SO2, and other compounds present in flue and stack gas. Tiger Optics analyzers have repeatedly outperformed traditional technologies, including FTIR, for this application in a variety of challenging comparison tests, and also proven their reliability and excellent performance in many CEM system installations. Because of the extremely low detection limits afforded by this advanced technology (e.g., 1 ppb HCl; 0.2 ppb HF; 3.5 ppb NH3) dilutive extraction can readily be used. This has several critical advantages vs. hot-wet measurements. High dilution ratios (e.g., 100:1) have the benefits:

  • Moisture interactions with the contaminant are minimized, greatly reducing corrosion and sample loss due to surface effects.
  • Unheated Teflon umbilicals can be used to transport the diluted stack gas long distances to a CEM shelter. Some customers use the same sample lines now feeding Mercury or other CEM monitors.

From trace HCl measurements to comply with US EPA rules, to continuous monitoring of ammonia slip for reducing the cost of abating NOx, Tiger units deliver reliably 24/7/365. The Tiger-i CEM has the ability to measure emissions in real-time both up on the stack and in CEM shelters on the ground. With its unmatched detection sensitivity, it can be integrated into existing CEMs dilution systems for easy installation and interference-free measurement.

Our HALO series (on which the Tiger-i is based) brings its signature accuracy and ease of use to makers of CEM calibration standards for continuous quality control. NIST, for example, used Tiger Optics technology to name their HCl reference gas standard.