Infra-red gas analyzer

Photosynthesis under natural conditions was measured with ADC portable Infra-Red Gas Analyzer Type LCA. 

The material to be analyzed is pyrolyzed in an inert gas at 1100°C in the presence of carbon the carbon monoxide formed, if any, is either analyzed directly by chromatography or analyzed as carbon dioxide after oxidation by CuO. The CO2 is detected by infra-red spectrometry or by gas phase chromatography. 

The mass spectrometer sampling capillary or the dispersive infra-red analyzers used for continuous analysis and monitoring of the gas phase composition are situated between the reactor and the sampling valve, as close to the reactor as possible, in order to avoid any delay in the recording of changes in the composition of reactants or products. This delay should be taken into account when plotting simultaneously the time dependence of catalyst potential or current and gas phase concentration of the reactants or products. 

In the process of developing PRMs, it is necessary to study and establish measurement methods which are used to analyzed the purity of raw gases and verify the stability of the gas mixture kept in the cylinder. Up to now, NRCCRM has been equipped with several series of analytical techniques including atmospheric pressure ionization mass spectrometer, gas chromatograph, infra-red spectrophotometer with long-path gas cell, chemiluminescent, non-dispersive infra-red, minor 02 and H20 analyzer and so on. 

To check the hypothesis that steam causes volatilization of copper, nickel and cobalt, two experiments were performed with a clean X-AI2O3 slice above a NiO/a-Al2C>3 sample [29]. The sample and the slice were separated from each other by two pieces of platinum wire (0 0.25 mm). The experimental set-up is shown in the inset of fig, 6, After treatment at 1000 °C for 70 hours in N2/O2/30% HjO or a dry N2/O2 gas flow, the bottom side of the upper a-AI2O3 slice was analyzed with RBS (figure 6). Clearly, in the presence of steam some nickel had been deposited onto the slice, but when steam had been absent no nickel was detected. We thus conclude that some nickel species, formed under the influence of steam, disappeared from the Ni0/a-Al203 sample into the vapour phase. We attribute this loss to the formation of volatile metal hydroxides 29,30. This is supported by Fourier Transform Infra Red (FTIR) Spectroscopy experiments [31]. 

The product gas passed through a cyclone that captured fine catalyst particles and any char generated in the reactor, then two heat exchangers to remove excess steam. The condensate was collected in a vessel whose weight was continuously monitored. The outlet gas flow rate was measured by a mass flow meter and by a dry test meter. The concentrations of CO2, CO, and CH in the reforming gas composition were monitored by a non-dispersive infra-red analyzer (NDIR Model 300 from California Analytical... 

At this point, the sample is analyzed by gas chromatography (GC), the analytical method of choice for volatile halogenated hydrocarbons. Information on the analysis of these samples by GC is presented in Section 6.2, with a discussion of the advantages and disadvantages of each method. The technique of Antoine et al. (1986) showed a 5% variance on a series of 2 ppb spiked samples, and the analysis had a linear response ranging from 0.5 to 50 ppb. Although infra-red spectrometry has less sensitivity than electron capture detectors (ECD), Hall electroconductivity detectors (HECD), and mass spectrometrlc detectors (MS), it has been used to quantify the levels of... 

Other examples of instruments that can be used for real-time monitoring of VOCs are gas analyzers based on non-dispersive infra red (NDIR) detection and Fourier transform infrared (FTIR) detection. The use of FTIR technique may under certain circumstances enable identification and quantification of individual VOCs at low concentrations (Hicks et al., 1992 and Bunding Lee et al., 1993). 

The use of analytical instruments to detect, analyze and rate the emissions has been a convention in this field (Rock et ai, 2008 Yamazoe and Miura, 1995) examples include instruments such as infra-red (IR) spectroscopy, ultraviolet (UV) absorption, chemiluminescence (Yamazoe and Miura, 1995) and gas chromatography/mass spectrometry (GC/MS) (James et al, 2005). These analytical techniques are associated with good limits of detection and fast response times (Akbar et al., 2006 Szabo et aL, 2003) however, they do suffer from various disadvantages - such as maintenance requirements, as well as weight and portability issues (Akbar et aL, 2006). They tend to be expensive and therefore are unsuited for tn-situ analysis or continuous operation (Rock et al, 2008). Data gathering may also be time-consuming with these methods (Yamazoe and Miura, 1995), and the requirement for trained personnel to utilise the instruments and conduct analysis also limits their effectiveness (James et al, 2005). 

All samples are taken through a heated sample line and all monitors are calibrated daily using cylinders of gas with two certified concentration ranges (e.g. 200 and 400 ppm) of NO -If N2O has to be determined, a different type of analyzer would be required, that uses an infra red source, narrow bandpass filters and a solid state IR detector. 

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