Applications Note – CEM of Turbine and IC Engine Exhaust by FT-IR
Advanced Fuel Research, Inc. has demonstrated the FT-IR based MG-2010 from
On-Line Technologies, Inc. during shake-down testing and continuous emission
monitoring (CEM) of turbine and internal combustion (IC) engines. The MG-2010 is
unique in its ability to monitor many species simultaneously over a very wide
concentration range, from sub-ppm to percent, at a fraction of the cost of
traditional multi-species emission stations. The MG-2010 replaces the
traditional rack of several individual gas analyzers with a single compact
instrument. The MG-2010 is also able to perform speciation of hydrocarbons and
report concentrations on species previously considered difficult to measure,
such as formaldehyde.
A benchmark comparison of the MG-2010 to a rack of traditional analyzers was
performed on a turbine test rig fired with natural gas at an Air Force test
facility (see Figure 1). The exhaust gas supplied to the MG-2010 was extracted
from the test rig using the same sampling rake and transfer line used by the
traditional analyzers. The MG-2010 recorded concentrations at 30-second
intervals (840 points over the 7 hours), while the traditional gas analyzers
reported concentrations for a total of 36 different test points.
A data trace of the NO concentration measured with the MG-2010 compared to
the 36 test points is shown in Figure 2. Good agreements in measurements were
also obtained for CO, CO2, total hydrocarbons and total NOx, but a limited
dynamic range was exhibited for the traditional CO (1000 ppm upper limit) and
total hydrocarbon (3000ppm upper limit) analyzers. The traditional total
hydrocarbon analyzer, a flame ionization detector, is a nonspecific hydrocarbon
analyzer. The MG-2010, on the other hand, is capable of speciating
hydrocarbons. Methane, formaldehyde, ethylene, propylene, and methanol
concentrations were individually measured using the MG-2010. It is important to
note that formaldehyde, which is on the EPA list of hazardous air pollutants, is
difficult to measure on a real time basis using any technique other than FT-IR.
In addition to the above species, nitrous acid (HONO) and formic acid (HCO2H),
were measured with the MG-2010 during this combustor development test.
The MG-2010 measured thirteen compounds simultaneously during this
head-to-head test with the traditional rack of analyzers. Excellent performance,
coupled with a small footprint and moderate price, make the MG-2010 an ideal
instrument for routine monitoring of engine exhaust emissions. Since this
benchmark comparison, exhaust emissions monitoring in industrial scale IC and
turbine engines have been performed, including ammonia slip from catalytic
reduction systems. The MG-2010 provided accurate, quantitative measurements for
single digit ppm levels of NO, NO2, N2O and NH3.
For more details and information, contact: Jim Markham (jim@AFRinc.com)