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Instruction Manual
IM-105-3000, Rev 2.0
November 2008
Appendix A
OVERVIEW
CORRELATION WITH
PARTICULATE DENSITY
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Dust Density Calculation
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page A-1
Correlation with Particulate Density . . . . . . . . . . . . . . . . . page A-1
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page A-5
mg/m3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page A-8
Transmissometers are used throughout the world for continuous monitoring of
opacity and particulate concentrations (also known as 'Dust Density'). The
OPM 3000 Opacity/Dust Density Monitor when factory-equipped with the
mg/m dust density option provides continuous and reliable measurements of
particulate concentrations in the stack.
The following paragraphs discuss the correlation method used for measuring
and calculating dust densities, an applicable off-stack zero calibration
procedure, and remote control unit setup and operation displays applicable to
the monitor when equipped for dust density calculation.
According to Bouger's Law the particulate density within an optical path is
directly proportional to the measured optical density of the path. The constant
of proportionally differs with the gravimetric density of the particulate matter,
its size distribution, and its optical properties. The constant can be calculated
when these data are known. In most cases, however, all of the required data
is not known. In practice, it is much easier to experimentally determine the
proportionality constant and offsets for each installation. As the resulting data
may not correlate well with a regression line through the origin, an offset is
required.
The correlation coefficient and offset of the linear relationship between optical
density and particulate density, typically mg/nm
regression analysis of a data set including simultaneous measurements of
optical density and dust density. Such data should cover as large a range of
operating variables as possible. Calibration, in terms of dust loading, is valid
as long as the particle size distribution and composition do not change
significantly. This condition is generally fulfilled in emissions from sources with
high efficiency particulate control equipment.
To establish the accuracy of the calibration over a range of emission rates and
process conditions, a large number of calibration points (at least 12 to 15)
should be obtained by Method 5 or 17 Isokinetic. Then the regression line and
associated confidence limits can be obtained. A substantial amount of data
has been developed for correlating optical density with dust loading for a
variety of applications. This data can be used as a starting point for
characterizing any specific source.
OPM 3000
3
, is determined from a linear
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