High-resolution FTIR analysis of coal gas

Abstract

Coal gas samples collected from a laboratory scale gasifier have been analysed using high-resolution (0.125 cm −1) Fourier transform infrared spectrometry (FTIR). The gas samples were introduced into an evacuated 8.76 m path-length gas cell and backfilled with nitrogen to 1 atm. Carbonyl sulphide and ammonia were quantified in samples with concentrations ranging from trace to 370 ppm, and non-detectable to 25 ppm, respectively. Other compounds identified in the coal gas samples include: methane, ethane, ethylene, ⪖C 3 hydrocarbons, acetylene, carbon monoxide, carbon dioxide, ethylene oxide, methane thiol, hydrogen cyanide, formaldehyde, cyanogen (?), ethane thiol (?), methanol, and nitric acid (?). Several compounds were sought but were not present in detectable quantities (less than ≈ 1 ppm). These include: nickel carbonyl, arsine, benzene, methyl chloride, methylamine, HCI, nitrogen oxides, and phosgene. Selected compounds, e.g. ammonia, were quantified by calibration with a standard gas. High resolution FTIR, a nearly universal detector, is especially useful for determining presence or absence of specific pollutants or interest which are not easily determined by routine gas chromatographie methods.