Remote quantification of smokestack effluent mass flow rates using imaging Fourier transform spectrometry

A Telops Hyper-Cam midwave infrared (1.5 - 5.5μm) imaging Fourier-transform spectrometer (IFTS) was used to estimate industrial smokestack total effluent mass flow rates by combining spectrally-determined species concentrations with flow rates estimated via analysis of sequential images in the raw interferogram cube. Measurements of the coalburning smokestack were made with the IFTS at a stand-off distance of 350m. 185 hyperspectral datacubes were collected on a 128(W)×64(H) pixel sub-window (11.4×11.4cm² per pixel) at a 0.5cm⁻¹ spectral resolution. Strong emissions from H₂O, CO₂, CO, SO₂, and NO were observed in the spectrum. A previously established single-layer radiative transfer model was used to estimate gas concentrations immediately above stack exit, and results compared reasonably with in situ measurements. A simple temporal cross-correlation analysis of sequential imagery enabled an estimation of the flow velocity at center stack. The estimated volumetric flow rate of 106±23m/s was within 4% of the reported value. Final effluent mass flow rates for CO₂ and SO₂ of 13.5±3.8kg/s and 71.3±19.3g/s were in good agreement with in situ rates of 11.6±0.1kg/s and 67.8±0.5g/s. NO was estimated at 16.1±4.2g/s, which did not compare well to the total NOx (NO +NO₂) reported value of 11.2±0.2g/s. Unmonitored H₂O, HCl , and CO were also estimated at 7.76±2.25kg/s, 7.40±2.00g/s, and 15.0±4.1 g/s respectively.