The acronym CEMS is a very thorough descriptor if we consider the full meaning of the words it contains:

• Continuous—The system has to work all the time, without interruption.
• Emissions—Plural, pointing out there are multiple pollutants involved.
• Monitoring—Constantly measuring and recording data on regulated pollutants under varying conditions.
• System—There are multiple elements, including sample extraction and preparation before it reaches the analyzer(s).

All of these points hinge on the analyzer, or traditionally, the collection of various analyzer types, necessary to cover the range of pollutants dictated by the fuel, or fuels, a given installation may burn. This has long been a complex discussion since most analyzer types are highly specialized and only handle one or maybe two pollutants. Thanks to Emerson’s gas analyzer developments, this is no longer the case, as I describe in my article in Power magazine, Smart Systems Power Up Modern Emissions Monitoring.

So how are technologies changing? Think for a moment about how these systems have been working traditionally.

One of the most pronounced pain points end users face is the fragmented and maintenance-intensive nature of traditional CEMS. These conventional systems many times require separate analyzers for every target gas, such as NO_x, SO₂, CO, as well as carbon dioxide (CO₂) and oxygen (O₂). These setups depend on extractive sampling, where a gas sample is pulled from the emissions stack, cooled to remove moisture, and conditioned prior to analysis. This entire system is full of potential failure points.

The fact that more power generating applications are using a wider range of possible fuels than they used to, calls for greater CEMS flexibility with changing flue gas profiles, which, given the situation just described, isn’t easy. New laser-spectroscopy-based analyzer technologies are making designing a CEMS much easier as a single analyzer can now handle multiple pollutants.

Today’s leading CEMS solutions replace conventional complexity with a single integrated advanced laser spectroscopy platform. This modern approach provides better accuracy, greater reliability, and lower costs of ongoing ownership, particularly in the natural gas and emerging power sectors. These solutions feature both quantum cascade laser (QCL) and tunable diode laser (TDL) technologies working in tandem, enabling detection of a multitude of gases.

Here are three examples of analyzers that Emerson offers using TDL and QCL technology:

• Rosemount™ CT5100 Continuous Gas Analyzer is the first hybrid, laser-based analyzer developed for process gas analysis and emissions monitoring. It combines QCL and TDL technologies to provide fast, direct and highly selective and sensitive measurement of multiple gas components simultaneously. It is available to house up to six lasers to measure up to 10 gas components in real time.
• Rosemount™ CT5400 Continuous Gas Analyzer is also a hybrid, QCL and TDL analyzer. It expands gas analysis to both the near and mid-infrared range, covering many gas species using a unique intra-pulse spectroscopic method able to detect up to 10 different gases simultaneously while providing fast response time and sub-parts per million gas analysis.
• Rosemount™ X-STREAM Enhanced XEGP Continuous Gas Analyzer measures up to five components simultaneously in various combinations. Its versatile design allows physical benches to be installed in their own compartment, separate from the electronics. It comes in a 19 inch rack mount or tabletop enclosure.

These are only a few of the options available. We can explain the subtle but important differences to these choices, so ask us what we can do for your CEMS application.

When backed by dedicated lifecycle services from trusted suppliers, these offerings provide complete compliance solutions, empowering professionals in the power generation industry to move beyond the incremental fixes and workarounds that have characterized emissions monitoring for decades. This holistic strategy is powering smart CEMS, adaptable to any regulatory environment now and for the foreseeable future.

For more information, visit Emerson’s Engineered Solutions pages at Emerson.com.