Combustion Analyser Offering Improved Process and Safety Functions

AMETEK Process Instruments (USA), a specialist in online analytical instrumentation, has introduced the next-generation in close-coupled extractive combustion analysers with the launch of the Thermox WDG-V combustion analyser for measuring oxygen, combustibles and methane levels in hot, wet flue gas.

The WDG-V analyser provides a reliable and cost-effective solution for monitoring combustion, reducing excess oxygen, lowering emissions of NOx, CO and CO₂ and improving operating efficiency. The reliable detection of low-combustion oxygen and/or high or low combustibles (CO) in a fired heater or boiler is critical to the effectiveness of burner management systems.

“We believe the WDG-V is the combustion analyser of the future,” comments Mike Fuller, Vice President of Marketing and Business Development for AMETEK Process Instruments & Analytical Instruments.  “The role of combustion analysers in control and safety functions is evolving rapidly. Maximising fuel efficiency, while reducing emissions from combustion processes, requires utilising aggressive operating set points that dictate the need for additional layers of safety for risk reduction.”

The addition of a WDG-V combustion analyser provides a layer of control and safety to a basic process control system, while significantly reducing the risk of an uncontrolled combustion event. The versatile instrument can enable control and safety permissive, interlock and shutdown functions for burner management and safety instrumented systems.

 “With the WDG-V, process plant operators have a highly reliable combustion analyser that reads accurately, verifies its accuracy and informs the operator what services are needed and when they are needed to maintain that accuracy,” notes Mr. Fuller.

“Our design goal with the WDG-V was to provide as much sensor and calibration performance monitoring, diagnostic self checks and operational data as possible to the user through graphical display, data logging and digital communication,” adds Mr. Fuller.

“The WDG-V analyser offers a complete solution for combustion process control and safety with redundancy and diagnostics that provide end users all of the information required to implement predictive and proactive maintenance programs.The instrument has been third-party certified for SIL-2 implementation into Safety Instrumented Systems.”

Among the unique features of the WDG-V combustion analyser are: An improved aspirator design with larger orifice sizes and improved response times even with flame arresters installed; Low-flow sample alarm that monitors combustion gas flow at the sensors and provides an indication of low sample flow; Automatic verification of cell and detector integrity for ensuring proper accuracy and operation; Cell and detector age tracking for proactive calibration or service scheduling.

The WDG-V can be installed as either as a stand-alone analyser with analogue/HART, discrete and Modbus RS-485 bi-directional communications or supplied in a typical “sensor/controller” configuration with the addition of an AME Vision HMI that provides a graphical display and membrane keypad, Modbus, TCP/IP Ethernet connection, embedded Web Enabled Interface and USB data collection port.

The Thermox WDG-V is based on a field-proven design pioneered by AMETEK more than 40 years ago.  Its close-coupled extractive sensor style is designed for fast response. It offers accuracy and ease of maintenance in a wide range of applications and is a superior alternative to in-situ probes, even in heavy particulate and high-temperature flue gas streams.

The WDG-V mounts directly to the process flange and is heated to maintain all sample wetted components above the acid dewpoint. Its air-operated aspirator draws a sample into the analyser and returns it to the process. A portion of the sample rises into the convection loop past the combustibles and oxygen cells and then back into the process.

This design gives a very fast response and is perfect for process heaters.  It features a reduced drift hot-wire catalytic detector that is resistant to sulphur dioxide (SO₂) degradation, and the instrument is suitable for process streams up to 3200^oF (1760^oC).