XCAM™ Extractive Continuous Ammonia Monitoring System
- Combines best of extractive and TDL measurement methods
- Provides benefits of TDL system without operational or alignment issues
- Accurate and reliable ammonia signal
- Maximize NOx reduction and minimize reagent consumption through integration with SNCR/SCR system controls
- Extractive probe design will allow average duct readings as well as specific area measurements
- Patent Pending
- Designed to minimize maintenance
Accurate ammonia monitoring combining the best of extractive and TDL measurement for SNCR and SCR applications
The Fuel Tech XCAM™ Extractive Continuous Ammonia Monitoring System is engineered to measure ammonia concentration for SNCR and SCR applications. The XCAM system utilizes a laser gas analyzer employing the Tunable Diode Laser Absorption Spectroscopy (TDLAS) method.
In a typical Tunable Diode Laser (TDL) installation, the transmitter and receiver are mounted directly to the ductwork. Since ammonia can convert to other compounds or be absorbed in ash at temperatures less than 500˚F, the ideal installation location for a TDL is upstream of the air heater. Installations of this type are difficult for a variety of reasons. Access is frequently difficult due to limited space existing between the economizer or catalyst outlet and the air heater inlet.
Benefits of TDL systems with the operational issues
The required alignment of the TDL device becomes very difficult, and thermal cycles can affect this alignment. Ash loading degrades the signal and in high ash environments, a longer TDL path length may not be possible. Maintenance is frequently difficult due to the installed location and the challenges with access.
XCAM systems are designed to solve the difficulties of a typical TDL installation. XCAM systems use a high temperature pressure blower to pull gas through a set of custom designed probes. The probes are specially designed for each application so that when gas is extracted, the sample is representative across the duct equally while minimizing the amount of ash extracted. A cyclonic separator isolates fly ash prior to TDL measurement. The extracted gas passes through the defined path length where the TDL measures the ammonia concentration. After passing across the TDL path, the gas is returned to the duct just downstream of the sample points along with the ash stream.
The output signal from Fuel Tech's XCAM modules can be directly fed into a SNCR or SCR control system allowing for online monitoring and urea or ammonia control adjustments. The extractive probe design allows for SNCR and SCR tuning. When all probes are in operation, the system measures the overall concentration of ammonia in the flue gas duct. Using the isolation valves, if the probes are selectively taken out of service, the extractive measurement can be used to indicate ammonia concentration in specific areas of the duct. In this way, the
XCAM system can essentially map the ammonia concentration in a cross section of the duct, and all of this for the same cost of one TDL device.
The XCAM system combines the accuracy and repeatability of a TDLAS measurement system with an extractive probe design. The system provides an ammonia concentration measurement averaged across the ductwork as opposed to a line of site reading. The probe design allows a mapping of the cross section without having to purchase multiple TDL analyzers. The extractive nature of the system provides for easy access, alignment and maintenance.