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05206H DCN5910 47
7.0 CALCULATING MOLY CONVERTER EFFICIENCIES
7.1 PURPOSE
To provide instructions on how to calculate the efficiency of a Moly converter
when using a GPT method of testing converters, by using the US EPA method,
where the actual concentration of ozone is not a factor in the accuracy of the
calculation of the converter efficiency. This procedure is based on the Code of
Federal Regulations, Title 40, Chapter I, subchapter C, Part 50, Appendix F.
7.2 TOOLS
API M700 calibrator with O3 Gen option (or equivalent)
7.3 PARTS
NONE
7.4 PROCEDURE
1. For the sake of numbers to input into this note, we have chosen 450 PPB NO
gas as our reference point, you don’t have to pick these values, they are just an
example. There is also an assumption that the analyzer has a good calibration
done @ 450 PPB NO span gas. If this is not the case, then once you are done
with the leak check on the analyzer input your 450 PPB NO span gas and
calibrate the analyzer.
NOTE: for the GPT to be performed correctly, there must be a minimum of 10%
MORE NO than O3 produced. For example, if the Ozone produced is 400 PPB
then the NO used must be 440 or more. Typically 450 PPB NO is made and 400
PPB of Ozone is produced.
2. Leak check machine to ensure that there are no leaks in the analyzer.
3. If you have input a CE factor into the instrument firmware (this would be in the
CAL-CONC-CONV-SET menu) other than 100%, change this back to 100% for
the duration of this test.
4. The first gas check is to test to see how much the converter is eating NO gas or
out gassing NO gas. Bypass the converter in the machine, by placing a short
piece of tubing in place of the converter. Perform a straight dilution with NO gas
and air as a diluent gas. Input this 450 PPB NO gas into the analyzer, allow the
machine to stabilize, and write down the NOx value on your data sheet on line 3.