The In-Plume Emission Test Stand: An Instrument Platform for the Real-Time Characterization of Fuel-Based Combustion Emissions

摘要

The In-Plume Emission Test Stand (IPETS) characterizes gaseous and particulate matter (PM) emissions from combustion sources in real time. Carbon dioxide (CO_2), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO_2), and other gases are quantified with a closed-path Fourier transform infrared spectrometer (FTIR). Particle concentrations, chemical composition, and other particle properties are characterized with an electrical low-pressure impactor (ELPI), a light-scattering particle detector, an optical particle counter, and filter samples amenable to different laboratory analysis. IPETS measurements of fuel-based emission factors for a diesel generator are compared with those from a Mobile Emissions Laboratory (MEL). IPETS emission factors ranged from 0.3 to 11.8, 0.2 to 3.7, and 22.2 to 32.8 g/kg fuel for CO, NO_2, and NO, respectively. IPETS PM emission factors ranged from 0.4 to 1.4,0.3 to 1.8,0.3 to 2.2, and 1 to 3.4 g/kg fuel for filter, photoacoustic, nephelometer, and impactor measurements, respectively. Observed linear regression statistics for IPETS versus MEL concentrations were as follows: CO slope = 1.1, r~2 = 0.99; NO slope = 1.1, r~2 = 0.92; and NO_2 slope = 0.8, r~2 = 0.96. IPETS versus MEL PM regression statistics were: filter slope = 1.3, r~2 = 0.80; ELPI slope = 1.7, r~2 = 0.87; light-scattering slope = 2.7, r~2 = 0.92; and photoacoustic slope = 2.1, r~2 = 0.91. Lower temperatures in the dilution air (～25℃ for IPETS vs. ～50 ℃ for MEL) may result in greater condensation of semi-volatile compounds on existing particles, thereby explaining the 30% difference for filters. The other PM measurement devices are highly correlated with the filter, but their factory-default PM calibration factors do not represent the sizernand optical properties of diesel exhaust. They must be normalized to a simultaneous filter measurement.