Combustion product analysis

In gas-solid extractions the sample is passed through a container packed with a solid adsorbent. One example of the application of gas-solid extraction is in the analysis of organic compounds for carbon and hydrogen. The sample is combusted in a flowing stream of O2, and the gaseous combustion products are passed through a series of solid-phase adsorbents that remove the CO2 and 1T20. 

The high temperatures in the MHD combustion system mean that no complex organic compounds should be present in the combustion products. Gas chromatograph/mass spectrometer analysis of radiant furnace slag and ESP/baghouse composite, down to the part per biUion level, confirms this behef (53). With respect to inorganic priority pollutants, except for mercury, concentrations in MHD-derived fly-ash are expected to be lower than from conventional coal-fired plants. More complete discussion of this topic can be found in References 53 and 63. 

Cast analysis of carbon is not appropriate for Type I. Sheet products analysis is appropriate for checking proper type of material. Extremely low carbon levels can be checked accurately usiag carbon-combustion chromatographic-type analy2ers. 

In the simplified a/s analysis of Section 4.2 we assumed identical and constant specific heats for the two streams. Now we assume semi-perfect gases with specific heats as functions of temperature but we must also allow for the difference in gas properties between the cooling air and the mainstream gas (combustion products). Between entry states (mainstream gas 3g, and cooling air, 2c) and exit state 5m (mixed out), the steady flow energy equation, for the flow through control surfaces (A + B) and C, yields, for a stationary blade row,... 

The analysis of combustion products presents problems of complexity similar to that of feedstock and raw fuel analysis. A highly complex matrix of aliphatic material often exists (as unburnt fuel in the combustion exhaust), whilst the species of interest, for example, carcinogens or mutagens are often at very low concentrations. A classic example of multidimensional GC is its use in the analysis of flue-cured tobacco essential oil condensate. 

The analysis of industrial samples such as the pyrolysis products of Turkish lignites has been carried out by using GC, SEC and coupled HPLC/GC (16). The combustion products of lignites result in atmospheric pollution. The pyrolysis of... 

During flame propagation, a constantly increasing amount of propellant combustion products is added to the igniter products, thereby producing a constantly increasing mass velocity of total gas. As a first approximation to the real situation, the following expression has been used in the theoretical analysis to account for this effect ... 

Figure 3-14 shows a schematic view of an apparatus for combustion analysis. The stream of oxygen used to bum the substance carries the combustion products out of the reaction chamber and through a series of traps. Each trap is designed to collect just one combustion product. The mass of each trap is measured before and after combustion, and the difference is the mass of that particular product. 

Catalytic combustion experiments have been performed in a flow reactor operating below the lower explosion limits using HC/02/He mixtures. The product analysis was done by gas chromatography. FT-IR spectra have been recorded with a Nicolet Magna 750 instrument, using conventional IR cells connected with evacuation-gas manipulation apparatus. The powder was pressed into self-supporting disks, calcined in air at 773 K and outgassed at 773 K for 20 minutes before experiments. 

Simultaneous analysis of C, H, and N in liquid or solid organic materials may be carried out after combustion in an oxygen atmosphere at temperatures up to 1000 °C. The gaseous combustion products (CO2, H2O, N2) are flushed with a carrier gas (helium) through a reductant, and quantification is obtained by GC. For analysis of O, the combustion is performed in helium over platinised carbon. Carbon monoxide formed is converted to CO2 by passage over CuO, and measured in the same manner as for analysis of C. A 2-3 mg sample is required. 

The desired enthalpy of formation of 6,6-dimethylfulvene was determined by Roth citing measurement of hydrogenation enthalpies, and chronicled by Pedley citing enthalpies of combustion and vaporization. The two results differ by 7 kJ mol-1. We have opted for Roth s value because it is in better agreement with a value calculated using Roth s force field method. It is also to be noted that measurement cited by Pedley for the neat condensed phase could be flawed by the presence of partially polymerized fulvene and neither elemental abundance of the compound nor analysis of the combustion products would have disclosed this. Likewise, the measured enthalpy of vaporization would not have necessarily uncovered this contaminant. 

Aircraft turbines in jet engines are usually fabricated from nickel-based alloys, and these are subject to combustion products containing compounds of sulphur, such as S02, and oxides of vanadium. Early studies of the corrosion of pure nickel by a 1 1 mixture of S02 and 02 showed that the rate of attack increased substantially between 922 K and 961 K. The nickel-sulphur phase diagram shows that a eutectic is formed at 910 K, and hence a liquid phase could play a significant role in the process. Microscopic observation of corroded samples showed islands of a separate phase in the nickel oxide formed by oxidation, which were concentrated near the nickel/oxide interface. The islands were shown by electron microprobe analysis to contain between 30 and 40 atom per cent of sulphur, hence suggesting the composition Ni3S2 when the composition of the corroding gas was varied between S02 02 equal to 12 1 to 1 9. The rate of corrosion decreased at temperatures above 922 K. 

Calculation of enthalpies of formation from the enthalpies of combustion of reactants and products This method is generally applicable for any combustible material for which the gross molecular formula is known. The enthalpies of combustion may be determined in a calorimeter using excess oxygen. Analysis of the combustion products may be appropriate. 

Determination of heat of combustion and analysis of combustion products [45] I... 

Isotopic analysis of amino acids containing natural abundance levels of 15N was performed by derivatization, GC separation, on-line combustion and direct analysis of the combustion products by isotope-ratio MS. The N2 gas showed RSD better than 0.1%c for samples larger than 400 pmol and better than 0.5%o for samples larger than 25 pmol. After on-column injection of 2 nmol of each amino acid and delivery of 20% of the combustion products to the mass spectrometer, accuracy was 0.04%e and RSD 0.23%o19. 

A combustion test was performed at 20 atm in a hydrogen-oxygen system. Analysis of the combustion products, which were considered to be in equilibrium, revealed the following ... 

The aim of the present work was to design and operate an apparatus in which stationary combustion and flames can be produced and sustained to pressures of 2000 bar and with environmental temperatures up to 500°C. Visual observation of the interior of the reaction vessel should be possible. Arrangements had to be made by which a gas flow of only a few microlitres per second could be fed steadily into the reaction vessel at pressures to two kilobar. A similar provision was necessary to extract small samples for product analysis at constant conditions. The principle of design and operation will be described. First results will be given for experiments with oxygen introduced into supercritical water-methane mixtures. 

X-ray analysis results show the formation of MgN as a combustion product of Mg-GAP pyrolants. The reaction occurs with nitrogen gas formed by the decomposition of GAP according to ... 

At the high combustion and exhaust temps shown in Tables 2 4, many of the combustion products will dissociate (eg C02 = C0+5402 H2 = 2H, etc). The effects of product gas dissociation constitute the greatest source of inaccuracy in the above ideal rocket analysis... 

An elementary analysis, based on the simplifying assumptions that the generated combustion product gases are ideal and that their heat capacities and composition are independent of temperature and pressure, yields the following expression for specific impulse ... 

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