The Application:
Complex combustion systems and processes require besides a fast In-Situ O2- measurement to
control the combustion, a quality measurement to adjust the combustion system at a level which
avoids the generation of CO. The control level around the point of CO generation is the optimum of the
combustion. AMS offers for this application the COe In-Line Flue gas probe AMS 3211-1500 with a
dual sensor which allows the measurement of O2 and unburnt Hydrocarbons. The unburnt
Hydrocarbons are measured as CO equivalent (COe). Due to the fast response of the dual sensor the
plant control can make use of the additional control value COe. The COe In-Line Flue gas probe AMS
3211-1500 can be operated with the Transmitter AMS 3220. The Transmitters is available as Twin-
Version to supply separate signals for O2 and COe.
EN 14181 and EN ISO 14956.
The Measuring principle:
The Sensor of the COe In-Line Flue gas probe AMS 3211-1500 is made of a electrochemical solid
electrolyte sensor of partially stabilised Zircon dioxide ceramic. The sensor has three electrodes:
- O2-sensitive Platinum electrode
- CO / H2-sensitive electrode made of Platinum / Precious metal alloy
- Platinum reference electrode
The measurement of COe with the COe In-Line Flue gas probe AMS 3211-1500 is not a CO
measurement in the classical sense. The Flue gas probe AMS 3211-1500 measures in-situ the
concentration of the sum of all combustible (oxidising) flue gas components such as CO and H2. The
result of the measurement is displayed as COe. In applications with a known fuel at a constant
composition the true CO concentration can be determined within limits. The COe In-Line Flue gas probe AMS 3211-1500 can be used for the measurement of O2 and Coe in Natural gas, Fuel Oil # 4,
Lignite and Hard coal. The measuring range of the component COe is 1000 PPMv. For a quality
measurement this range is quite sufficient, since the main purpose of the measurement is to avoid the
generation of Carbon Monoxide. Due to the physical dimensions the sensor for measurement of O2
and COe can also be utilised with all other flue gas probes of AMS.
The Measuring system:
Typically continuous Oxygen measuring systems are consisting of a Flue gas probe with built in Zircon
dioxide sensor, a Transmitter and a Pneumatic unit. The Pneumatic unit supplies continuously
instrument air to the Zircon dioxide sensor which serves as Reference air. Via a second gas inlet port
at the probe flange the Zircon dioxide sensor can be supplied with calibration gas to verify and correct
the calibration of the sensor in regular intervals The Pneumatic unit and the Flue gas probe are
connected by two high pressure pneumatic hoses. A multi wire, protected cable connects the
Transmitter to the Flue gas probe electronically. To calibrate the COe In-Line Flue gas probe AMS
3211-1500 both components O2 and CO have to be verified against a certified standard gas.