Understanding CDM Methodologies - SuSanA

Box 27: Ensuring accuracy of measurements in secondary catalytic N 2
O
abatement projects
Most complex
Monitoring
Procedure in CDM
AM0034 requires the utilization of the use of the European Norm EN 14181
“Quality assurance for automated measuring systems”. Simply speaking the
norm specifies a number of tests/calibrations that need to be performed on the
monitoring equipment for N 2
O concentration measurements in order to ensure
data accuracy to the highest standard possible. First of all, EN 14181 requires the
monitoring instruments to be used not to exceed pre-defined uncertainty ranges.
If equipment fails the test, it may not be usable for baseline and project campaign
measurements. This has led to the situation where project proponents needed
to revise parts of their monitoring system installed in the process in order to
comply with EN 14181. During the baseline campaign the installed measurement
equipment needs to be calibrated with the so called “Standard Reference
Method” by an independent testing laboratory to ensure reliable results of
monitoring. This also needs to be done during the first project campaign. During
project operation the monitoring system is subject to on-going quality assurance
(to be performed continuously by the plant owner) and annual surveillance test
(to be performed annually by an independent testing laboratory).
Monitoring shall be conducted on the following items:
Ex ante
The following data needs to be gathered for the previous five complete
campaigns before request for registration:
• Oxidation temperature and pressure and its normal range
• Ammonia to gas flow rates and ammonia to air ratio in the reactor
• Gauze supplier and composition
• Normal campaign length
• Regulations on N 2
O emission threshold, if any
Baseline Data
Requirements
The following data needs to be gathered during the baseline campaign (see
Box 28 for timing of baseline campaign):
• N 2
O concentration in the stack gas
• Volume flow rate of the stack gas
• Length of the baseline campaign
• Nitric acid production
• Oxidation temperature and pressure and its normal range
• Ammonia to gas flow rates and ammonia to air ration in the reactor
• Overall uncertainty of the monitoring system (combined uncertainty of all
monitoring equipment)
• Gauze supplier and composition
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