Carbon by combustion

A dry combustion-direct injection apparatus was applied to water samples by Van Hall et al. [51 ]. The carbon dioxide was measured with a non-dispersive infrared gas analyser. Later developments included a total carbon analyser [97], a diffusion unit for the elimination of carbonates [98], and finally a dual tube which measured total carbon by combustion through one pathway and carbonate carbon through another. Total organic carbon was then calculated as the difference between the two measurements [99]. 

The ACHEX data base (10) from monitoring stations at Dominguez Hills, Riverside and West Covina in summer and early fall of 1973 have been reexamined. Of particular Interest in this context are the aerosol samples (no size fractionation) with collection times ranging from 2 to 6 hours which were analyzed for total carbon by combustion and for lead by x-ray flourescence. These data, plotted in Figure 1, do not show any strong correlation. 

Firstly from a comparison of the integrated area ratios for the F ls and Cls levels and secondly from the individual components of the Cis levels. This readily establishes that the materials are copolymers of ethylene and tetrafluoroethylene which are largely alternating in character and that the outermost surface sampled by ESCA is identical in composition to the bulk. This is shown in Table 4 where a comparison is drawn with compositions determined by standard microanalysis (carbon by combustion, fluorine by potassium fusion). ESCA is highly competitive as a routine means of establishing compositions for fluoropolymers in particular, in terms of accuracy, nondestructive nature and speed. 

Adsorption by activated carbon is commonly employed for the removal of TNT from aq waste streams, eg, pink water formed in shell-loading operations. Low efficiency in regeneration of the carbon for reuse has led to a study of the factors involved (Ref 99), with conclusions as follows. The TNT is adsorbed at many of the numerous high-energy sites on the surface of the carbon. Basic materials, introduced during activation of the carbon by combustion and oxidation and also present at these sites, then induce oxidation-reduction reactions of the methyl with the nitro groups in the TNT. This is... 

An extensive literature exists on the characterization and structure—activity correlation of industrial copper-alumina oxychlorination catalysts [95-120]. At least two different major copper species have been identified. At low concentrations of copper (below ca 5 %), a well-dispersed copper species in intimate interaction with the alumina surface is formed. This species has a very low oxychlorination activity. At higher concentrations, a second species, probably formed by the de-position/precipitation of the copper chloro complexes, is observed. The latter gives rise to the active sites during the oxychlorination reaction. On the basis of an FTIR study of the oxychlorination reaction Finocchio et al. [42] postulated the formation of surface copper chloride-ethylene r-complex intermediates (which lead eventually to EDC) and weakly adsorbed HCl during oxychlorination. Formate species associated with copper and probable precursors for formation of the oxides of carbon by combustion were also identified. 

West, D.L., 1964. Determination of total carbon by combustion gas-chromatography. Anal. Chem., 36 2194—2195. 

The estimation of particulate carbon by combustion in o gen is a more accurate method for the determination of total carbon than the method previously described (IV.4.I). However, although the measurement of oxidized products other than carbon is avoided, care must be taken not to include inorganic carbon from carbonates in any method involving combustioa The apparatus required for the determination of carbon by combustion is much more extoisive than that required in the previous method, and is not particularly suitable for shipbome operations. 

Soil organic matter Total organic carbon by combustion... 

Hafnium metal is analy2ed for impurities using analytical techniques used for 2irconium (19,21,22). Carbon and sulfur in hafnium are measured by combustion, followed by chromatographic or in measurement of the carbon and sulfur oxides (19). Chromatographic measurement of Hberated hydrogen follows the hot vacuum extraction or fusion of hafnium with a transition metal in an inert atmosphere (23,24). 

SL/RN Process. In the SL/RN process (Fig. 4), sized iron ore, coal, and dolomite are fed to the rotary kiln wherein the coal is gasified and the iron ore is reduced. The endothermic heat of reduction and the sensible energy that is required to heat the reactants is provided by combustion of volatiles and carbon monoxide leaving the bed with air introduced into the free space above the bed. The temperature profile in the kiln is controlled by radial air ports in the preheat zone and axial air ports in the reduction zone. Part of the coal is injected through the centerline of the kiln at the discharge end. The hot reduced iron and char is discharged into an indirect rotary dmm cooler. The cooled product is screened and magnetically separated to remove char and ash. 

Generally, cmde sulfur contains small percentages of carbonaceous matter. The amount of this impurity is usually determined by combustion, which requires an exacting technique. The carbonaceous matter is oxidized to carbon dioxide and water the carbon dioxide is subsequently absorbed (18). Automated, on-stream determination of impurities in molten sulfur has been accompHshed by infrared spectrophotometry (35). 

Carbon. Most of the Earth s supply of carbon is stored in carbonate rocks in the Hthosphere. Normally the circulation rate for Hthospheric carbon is slow compared with that of carbon between the atmosphere and biosphere. The carbon cycle has received much attention in recent years as a result of research into the possible relation between increased atmospheric carbon dioxide concentration, most of which is produced by combustion of fossil fuel, and the "greenhouse effect," or global warming. Extensive research has been done on the rate at which carbon dioxide might be converted to cellulose and other photosyntheticaHy produced organic compounds by various forms of natural and cultivated plants. Estimates also have been made of the rate at which carbon dioxide is released to soil under optimum conditions by various kinds of plant cover, such as temperature-zone deciduous forests, cultivated farm crops, prairie grassland, and desert vegetation. 

Commercially produced barium is analyzed for metallic impurities by means of emission spectroscopy. Carbon content can be deterrnined by combustion, and nitrogen by the Kjeldahl method. Total barium can best be deterrnined gravimetricaHy by precipitation as the sulfate. 

Total carbon in beryUium is determined by combustion of the sample, along with an accelerator mixture of tin, iron, and copper, in a stream of oxygen (15,16). The evolved carbon dioxide is usuaUy measured by infrared absorption spectrometry. BeryUium carbide can be determined without interference from graphitic carbon by dissolution of the sample in a strong base. BeryUium carbide is converted to methane, which can be determined directly by gas chromatography. Alternatively, the evolved methane can be oxidized to carbon dioxide, which is determined gravimetricaUy (16). 

Commercially produced calcium metal is analyzed for metallic impurities by emission spectroscopy. Carbon content is determined by combustion, whereas nitrogen is measured by Kjeldahl determination. 

The formation of carbon black in a candle flame was the subject of a series of lectures in the 1860s by Michael Faraday at the Royal Institution in London (23). Faraday described the nature of the diffusion flame, the products of combustion, the decomposition of the paraffin wax to form hydrogen and carbon, the luminosity of the flame because of incandescent carbon particles, and the destmctive oxidation of the carbon by the air surrounding the flame. Since Faraday s time, many theories have been proposed to account for carbon formation in a diffusion flame, but controversy still exists regarding the mechanism (24). 

Hydrochloric acid may conveniently be prepared by combustion of hydrogen with chlorine. In a typical process dry hydrogen chloride is passed into a vapour blender to be mixed with an equimolar proportion of dry acetylene. The presence of chlorine may cause an explosion and thus a device is used to detect any sudden rise in temperature. In such circumstances the hydrogen chloride is automatically diverted to the atmosphere. The mixture of gases is then led to a multi-tubular reactor, each tube of which is packed with a mercuric chloride catalyst on an activated carbon support. The reaction is initiated by heat but once it has started cooling has to be applied to control the highly exothermic reaction at about 90-100°C. In addition to the main reaction the side reactions shown in Figure 12.6 may occur. 

Incineration The conversion of dewatered wastewater solids by combustion (burning) to ash, carbon dioxide, and water vapor. 

Determine the empirical formula of an organic compound containing carbon, hydrogen, and oxygen by combustion analysis (Example M.4). 

Which starting condition would produce the larger volume of carbon dioxide by combustion of CH4(g) with an excess of oxygen gas to produce carbon dioxide and water (a) 2.00 I. of CH4(g) (b) 2.00 g of CH4(g) Justify your answer. The system is maintained at a temperature of 75°C and 1.00 atm. 

Which starting condition would produce the larger volume of carbon dioxide by combustion of C>H4(g) with an excess of oxygen gas to produce carbon dioxide and water ... 

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