A Dilution CEMS offers the lowest maintenance of any Continuous Emissions Monitoring Systems (CEMS) by its elimination of sample conditioners and pumps. Compressed air is used to "power" the Dilution CEMS. It is sent up the stack where it is mixed with the stack gas at a 100:1 ratio (typ.). The sample is then pushed down to the analyzers. Besides the stack gas being diluted, the moisture in the stack is also diluted allowing the sample to be measured directly in the analyzers without causing any harm.
Dilution CEMS have been used for 30+ years. They are still sold today in applications where the pollutant levels are high enough to be measured after dilution. If the NOx, SO2, and CO to be measured are over 30-40 ppm, you might be a candidate for a Dilution CEMS (moisture present is also a deciding factor). Dilution CEMS are not used for NH3 or THC measurement. Typical applications include coal and wood boilers.
Being a "wet" basis measurement, Dilution CEMS work in perfect conjunction with flow monitors which also measure on a wet basis. They eliminate the need for moisture correction with either a constant or a moisture analyzer.
Monitoring Solutions builds a superior Dilution CEMS utilizing our own dilution controller. An out-of-stack dilution probe makes modern Dilution CEMS even easier to service, and no sample conditioning equipment means a clean cabinet design with plenty of access for the limited maintenance required. Add our CEMDAS and you have a complete system to meet your compliance monitoring requirements.
You can read more about this application on our blog.