Teledyne manual M201A Ammonia Analyzer, Principle of Operation

Teledyne API Model 201A NH3 Analyzer Instruction Manual, 04689, Rev. B1

1.0 M201A AMMONIA ANALYZER

This manual is to be used in conjunction with the M200A NOx Analyzer manual p/n 02246 supplied with this instrument.

The M201A Ammonia Analyzer consists of a modified M200A Nitrogen Oxides Analyzer and M501NH Ammonia Converter:

A functional block diagram of the system is shown in Figure 1.

The instrument comes in three pneumatic configurations:

•The basic system is shown in Figure 3;

•The M201A with Z/S valves is shown in Figure 4;

•The M201A with External Calibrator Option (ECO) is shown in Figure 5.

Figure 2 can be used to connect the M201A system for installation. Please note that for a M201A with either a Zero/Span or ECO option, you must connect the umbilical cord, 02255, between the analyzer and the converter assembly.

1.1 Principle of Operation

The Teledyne API Model 201A Analyzer measures ammonia by converting NH3 to nitric oxide by the following reaction:

4NH3 + 5O2 → 4NO + 6H2O

The resulting NO is then measured by the chemiluminescent reaction of NO with ozone. Consult Section 4.1 in the M200A manual (provided with this instrument) for more details on NO measurement.

A molybdenum converter is continuously in the pneumatic pathway, providing the TN channel signal. The M501NH ammonia converter is periodically switched so both converters are in series, creating the TNx signal.

The ammonia concentration is computed by the difference between the TNx and TN channels, as shown in the following equation:

NH3 → TNx - TN

See the pneumatic diagram in Figure 1.

The actual formula for computation of ammonia concentration is more complicated than the above equation, as it includes converter efficiencies, plus sample temperature and pressure. The difficulty in ammonia measurement is that the molybdenum converter

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