Tip of the Week
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A Little
History |
Sometimes
we take certain procedures, equations and constants for granted in our business,
without ever wondering how these things became so entrenched. When the 1970
Clean Air Act was first implemented, emissions test methods and procedures had
to be developed concurrently with the enforcement of the emissions standards.
Simple procedures that we accept today as gospel had to proposed, tested and
peer-accepted before they could be used for regulatory purposes.
For
instance, we’re all familiar with the calculation of emissions in units of
lb/MMBtu using fuel-specific F-Factors. But when the Clean Air Act was first
enforced, the only acceptable approach for determining this was through using
actual heat input measurements, a cumbersome process that had a high margin of
error. It took over six years to develop the necessary procedures that we now
take for granted in Method
19.
Various USEPA papers were published in the mid-1970’s that
describe in great detail how the different F-Factor methods for calculating
power plant emission rates were developed. These papers were originally
published in the Source Evaluation Society Newsletter, and are available now in
Technical Information Document TID 020 on the EPA’s
EMC website (www.epa.gov/ttn/emc).
In addition
to describing the derivation and use of F-factors, these papers also describe
some of the problems and errors that arise in applying the F-Factor method, as
well as other less-known uses of the F-Factors. They contain a lot of
information than can be useful when trying to understand the relationships
between O2, CO2, thermal input and gas flow rate of
combustion processes.