Carbon dioxide mixing ratios

Ethylene is to be converted by catalytic air oxidation to ethylene oxide. The air and ethylene are mixed in the ratio 10 1 by volume. This mixture is combined with a recycle stream and the two streams are fed to the reactor. Of the ethylene entering the reactor, 40% is converted to ethylene oxide, 20% is converted to carbon dioxide and water, and the rest does not react. The exit gases from the reactor are treated to remove substantially all of the ethylene oxide and water, and the residue recycled. Purging of the recycle is required to avoid accumulation of carbon dioxide and hence maintain a constant feed to the reactor. Calculate the ratio of purge to recycle if not more than 8% of the ethylene fed is lost in the purge. What will be the composition of the corresponding reactor feed gas ... 

Various workers have discussed the determination of total alkalinity and carbonate [ 10-12], and the carbonate bicarbonate ratio [ 12] in seawater. A typical method utilises an autoanalyser. Total alkalinity (T milliequivelents per litre) is found by adding a known (excess) amount of hydrochloric acid and back titrating with sodium hydroxide solution a pH meter records directly and after differentiation is used to indicate the end-point. Total carbon dioxide (C milliequivelents per litre of HCO3 per litre) is determined by mixing the sample with dilute sulfuric acid and segmenting it with carbon dioxide-free air, so that the carbon dioxide in the sample is expelled into the air segments. The air... 

The atmospheric composition of Venus is similar to that of Mars (see Table VIII—3). Carbon dioxide is the main constituent. The CO mixing ratio is about 5 x 10"5, but the Oz mixing ratio is less than 10 6. Minor constituents that are present in the Venus atmosphere but not in the Martian atmosphere are HC1 and HF in mixing ratios of 6 x 10 7 and 1.5 x 10 9, respectively. 

Ruthenium complexes with mixed bipyridyl ligands, immobilized inside a Nation film, may also be used as pH-sensitive sensor layers [90]. A completely different approach for a ratiometric imaging of pH sensor foils was developed for diagenetic studies of marine sediments, using the dual fluorescence excitation ratio of the pH-sensitive fluorophore 8-hydroxypyrene-l,3,6-trisulfonic acid (HPTS) [91]. Commonly used dual fluorophors with different absorption and emission maxima in the protonated and basic form for ratiometric measurements are the naphthofluorescein and seminaphthofluorescein derivates (SNARF and SNAFL) [92], It should be noted that ammonia or carbon dioxide can also be detected by some of these pH-sensitive materials [55,93]. 

Naphtha and other oils can be converted to substitute natural gas. The processes use mix naphtha with steam in a 1 2 ratio and gasify the mixture. The gas produced is methanated by the reaction of the carbon oxides with the hydrogen present. Purification requires the removal of any residual carbon dioxide. 

In the process, a 2 1 molar ratio of ammonia and carbon dioxide (excess ammonia) are heated in the reactor for 2 hours at 190°C and 1500 to 3000 psi (10.3 to 20.6 MPa)to form ammonium carbamate, with most of the heat of reaction carried away as useful process steam. The carbamate decomposition reaction is both slow and endothermic. The mix of unreacted reagents and carbamate flows to the reactor-decomposer. The reactor must be heated to force the reaction to proceed. For all the unreacted gases and undecomposed carbamate to be removed from the product, the urea must be heated at lower pressure (400 kPa). The reagents are reacted and... 

Butyllithium replaces with lithium both the hydrogen in l-chloro-1,2-difluoroethylene and the chlorine in another molecule of the same compound, in a ratio of 1 2. Subsequent treatment of the reaction mixture with carbon dioxide, water, and esterification with methanol gives a mix-... 

Other reagents and solvents were obtained from commercial sources. The samples were prepared by mixing various chiral bases with racemic acids in 0.5 1 molar ratio. A porous supporting material (Perfilt), impregnated with these mixtures, was put into the extractor vessel and extracted with supercritical carbon dioxide. 

Using formate, Sutton and Winterbourn [111,132,133] also presented evidence that the reaction of Fe2+-edta and aqueous, unchelated, iron(II) with hydrogen peroxide involves in part a higher oxidation state of iron. This experiment involves a chain of reactions, which on the basis of the known rate constants, would have a very large number of cycles before it would come to an end. Instead, fewer than 10 cycles were observed, see below. These experiments have been extended to other ligands. In rapid-mix experiments a solution of iron(II) complex [or iron(II)], formate and PQ + is mixed with hydrogen peroxide and the ratio of carbon dioxide produced per paraquat oxidised (the number of cycles) is determined. Alternatively, paraquat radicals are generated... 

Description Natural gas or another hydrocarbon feedstock is compressed (if required), desulfurized, mixed with steam and then converted into synthesis gas. The reforming section comprises a prereformer (optional, but gives particular benefits when the feedstock is higher hydrocarbons or naphtha), a fired tubular reformer and a secondary reformer, where process air is added. The amount of air is adjusted to obtain an H2/N2 ratio of 3.0 as required by the ammonia synthesis reaction. The tubular steam reformer is Topsoe s proprietary side-wall-fired design. After the reforming section, the synthesis gas undergoes high- and low-temperature shift conversion, carbon dioxide removal and methanation. 

At a one-to-one pressure ratio of ethylene to<arbon monoxide of around 1000 psig, the major product is succinate this is in contrast to the production of acrylic acid, where succinic add was not isolated. If the olefin is left out of the reaction mix, then oxalates are produced and this is a practical route to oxalates, particularly at carbon monoxide pressures above 500 psig. The formation of water is a severe problem for the stability and activity of the catalytic system, since in the presence of water there is a parallel reaction which produces considerable amounts of carbon dioxide. 

Fig. 8. Vertical distribution of molecular oxygen (Oj) mixing ratio in prebiological paleo-atmosphere. Calculations for molecular hydrogen (Hj) = 17 ppmv, carbon dioxide (CO2) = 280 ppmv, and three different solar ultraviolet fluxes.

A mixture of carbon monoxide, hydrogen, and carbon dioxide is produced by steam reforming, a process in which natural gas and steam are mixed and reacted in a reformer operated at 1.6 MPa. Natural gas may be assumed to consist entirely of methane (CH4), although other compounds may be present in small concentrations. In the present process, steam and natural gas are fed to the reformer in a ratio of 3.0 moles of steam per mole of methane. The reformer consists of an arrangement of vertical tubes filled with nickel-impregnated ceramic catalyst. Rows of these tubes are located inside an insulated firebox, where they are heated by the combustion of natural gas. 

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