Volatile species diagram

Figure 4.2 — (A) Schematic diagram of an ammonia-N-sensitive probe based on an Ir-MOS capacitor. (Reproduced from [20] with permission of the American Chemical Society). (B) Pneumato-amperometric flow-through cell (a) upper Plexiglas part (b) metallized Gore-Tec membrane (c) auxiliary Gore-Tec membrane (d) polyethylene spacer (e) bottom Plexiglas part (/) carrier stream inlet (g) carrier stream outlet. (C) Schematic representation of the pneumato-amperometric process. The volatile species Y in the carrier stream diffuses through the membrane pores to the porous electrode surface in the electrochemical cell and is oxidized or reduced. (Reproduced from [21] with permission of the American Chemical Society).

A PT diagram for the ethane/heptane system is shown in Fig. 12.6, and a yx diagram for several pressures for the same system appears in Fig. 12.7. According to convention, one plots as y and x the mole fractions of the more volatile species in the mixture. The maximum and minimum concentrations of the more volatile species obtainable by distillation at a given pressure are indicated by the points of intersection of the appropriate yx curve with the diagonal, for at these points the vapor and liquid have the same composition. They are in fact mixture critical points, unless y = x = 0 or y = x = 1. Point A in Fig. 12.7... 

Tits Schematic diagram of an integrated gas-diffusion separation optosensing detection system. A. acceptor stream with reagent S, reacted sample with generated volatile species ... 

E. A. Gulbransen and G. H. Meier, Themodynamic stability diagrams for condensed phases and volatility diagrams for volatile species over condensed phases in twenty metal-sulfur-oxygen systems between 1150 and 1450 K. University of Pittsburgh, DOE Report on Contract no. DE-AC01-79-ET-13547, May, 1979. 

It should be noted that bubbles in the extrudate are not only a sign of air entrapment, but it may also be an indication of moisture, surface agents, volatile species in the polymer itself, or degradation as shown in the fishbone diagram shown in Fig. 11.36. 

As the volatility diagrams indicate, in most cases a stable Si02 film is present on a SiC or Si3N4 substrate in all but the lowest oxygen potentials. At high temperatures, the silicon dioxide scale reacts with the SiC or Si3N4 substrate, generating volatile species as ... 

FIGURE 8.10 Activity coefficients for water-sulfuric acid at 200°C [8, p. 2-83]. Observe that the least volatile species, sulfuric acid, is chosen as species a. This is contrary to the standard convention, but the normal way of showing water-sulfuric acid diagrams. This equilibrium is complicated by the formation of several weak intermolecular compounds and by the presence of free SO3 in the equilibrium vapor. Nonetheless, it shows that for species that form such weakly-bonded quasi-compounds, the equilibrium activity coefficients can be quite small. 

Fig. 14.10 Reaction path diagram [149] illustrating major steps in volatile-N conversion in flames for different nitrogen species hydrogen cyanide (HCN), ammonia (NH3), cya-nuric acid (HNCO), acetonitrile (CH3CN), and pyridine (C5H5N). The diagram is based on chemical kinetic modeling at moderate fuel-N concentrations. Solid lines denote elementary reaction pathways, while dashed arrows denote routes that involve intermediates and reactions not shown.

Figure 10.49. Model calculation simulating changes in ocean composition as primary igneous rock minerals react with a solution containing the proportions of "excess volatiles" shown in Table 10.4. Concentrations of dissolved species are shown relative to 1 kilogram of water, and the extent of reaction is measured by the amount of igneous-rock minerals destroyed. Changes in slopes on diagram are due to formation of sedimentary minerals. (After Lafon and Mackenzie, 1974.)...

Aluminum hydroxy species, 65,69,160 Stability constants, 69 Stability diagrams, 78 pH of minimum solubility, 65, 71, 72 Ammonium, 326, 331 Volatilization, 330 Oxidation, 334-336,472 Nitrate, 334-336,472 Adsorption, 336,465-466 Metal-ammine complexes, 460—461, 465... 

For all other things to be equal, the amounts of the species must be the same and the relative volatility between all adjacent pairs of species must also be the same. For example, in the case of a four-species feed having equal amounts of each species (e.g., 1 kmol/h each) and relative volatilities of ad 1-2 = 1.728, bd = 1-2 = 1.44, q cd = 1-2 = 1.2, and Odd = 1.2 = 1, all other aspects of the problem [would be] equal. For each binary split (e.g., A/B or B/C), the McCabe-Thiele diagram would be drawn with the equilibrium curve based on a relative volatility of 1.2. 

The boundary is curved. This, too, can be partially predicted by noting that the infinite-dilution A -values for acetone and chloroform in lots of benzene indicate that acetone is more volatile. Therefore, chloroform acts like an intermediate species in the benzene-rich end of the diagram. The residue curves start out aiming at chloroform from benzene. 

The Global Mercury Cycle A recent review (Mason et al., 1994) on the global Hg cycling is diagrammed in Figure 10.24. The evasion of Hg from the ocean is balanced by the total oceanic deposition of Hg(II) from the atmosphere. The mechanisms, whereby reactive Hg species are reduced to volatile Hg in the oceans, are poorly known, but reduction appears to be biologically mediated. Deposition on land is the dominant sink for atmospheric Hg. Mason et al. (1994) estimate that over the last century anthropogenic emissions have tripled the concentration of Hg in the atmosphere and in the surface ocean. 

Consider the separation problem of Fig. 1.18, which is adapted from Heaven. Three essentially pure products and one binary product (pentanes) are to be recovered. Table 1.6 is a list of the five species ranked according to increasing normal boiling point. Corresponding approximate relative volatilities at 1 atm between species of adjacent boiling points, as determined from Fig. 1.17, are also included. At least three two-product separators are required to produce the four products. Because none of the relative volatilities are close to one, ordinary distillation is probably the most economical method of making the separations. As shown in the block flow diagrams of Fig. 1.19, five different sequences of three distillation columns each are possible, from which one must be selected. 

Fig. 5 Schematic diagram of a typical FI manifold with gas-diffusion separation and volume-based sampling. CR. carrier stream S, sample R. reagent for formation of volatile analyte species SP. membrane gas-diffusion separator, A. acceptor stream D, detector and W, waste outlets for donor and acceptor streams.

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