Residual gas composition

In freeze-fracture preparations made without consideration of the residual gas composition in relation to specimen temperature, water vapor can condense on the frozen specimen. This can occur nonrandomly on the fracture surface, giving the impression of membrane particles that aren t there or masking those that are. 

Furthermore, possibilities of influencing through manufacturing parameters were found e.g. [154]. These are substrate temperature, condensation rate, residual gas composition and pressure, angle of incidence of the vapour beam, and ion bombardment. 

Recompressor. Although not shown here, a similar comparison can be made for a case using recompression by choosing an estimated residue gas composition. The design basis is ... 

If the assumed areas are small enough, the feed and residue gas compositions for each AA are similar enough that the driving force for permeation can be based on the composition of the feed rather than on an average of the feed and residue compositions. The permeate composition for each incremental area must take into account the permeation rates of all components, but is not affected by permeate from the other areas. 

Synthesis Gas Preparation Processes. Synthesis gas for ammonia production consists of hydrogen and nitrogen in about a three to one mole ratio, residual methane, argon introduced with the process air, and traces of carbon oxides. There are several processes available for synthesis gas generation and each is characterized by the specific feedstock used. A typical synthesis gas composition by volume is hydrogen, 73.65% nitrogen, 24.55% methane, <1 ppm-0.8% argon, 100 ppm—0.34% carbon oxides, 2—10 ppm and water vapor, 0.1 ppm. 

The effect of synthesis gas composition on conversion, catalyst life, carbon black formation, etc. was determined in numerous tests. Characteristic variables in the synthesis gas composition are the H2/CO ratio, residual C02 content, and content of trace components in the form of higher hydrocarbons and catalyst poisons. 

A significant feature of the operation of the two plants is that only a small deviation in feed gas composition is tolerable when using a stoichiometric gas. Greater deviations in the H2/CO ratio and in the residual C02 content of the feed gas will cause serious problems regarding SNG specifications. Thus, methanation of a stoichiometric synthesis gas is reasonable only when there are no stringent requirements for SNG specification. 

Products of Combustion For lean mixtures, the products of combustion (POC) of a sulfur-free fuel consist of carbon dioxide, water vapor, nitrogen, oxygen, and possible small amounts of carbon monoxide and unbumed hydrocarbon species. Figure 24-10 shows the effect of fuel-air ratio on the flue gas composition resulting from the combustion of natural gas. In the case of solid and liquid fuels, the POC may also include solid residues containing ash and unbumed carbon particles. 

Area of the pay zone Thickness of the pay zone Open porosity Residual water saturation Initial reservoir pressure Reservoir temperature range Reservoir water salinity Water-free gas composition... 

Measurement of total pressure is insufficient for the characterisation of vacuum systems. Detailed information (system cleanliness, presence of leaks, etc.) can only be obtained by the identification of components present in the gas phase by means of residual gas analysis. Having established gas composition, however, the determination of partial pressures is relatively straightforward. 

The composite electrode was prepared from 100x4x6 graphite rods. Lanthanum carbonate was applied to the rod surface from aqueous suspension, dried at room temperature, mounted into a reactor (Fig. 1) and kept for 8-10 h in residual gas (10 2 Pa) and helium under DC of 50-70 A. To perform arc discharge process helium pressure, voltage and DC were maintained within the ranges of 2 104-3 104 Pa, 20-25 V and 100-150 A, respectively. 

C. Soaking Phase. The soaking phase takes place in the rest of the reactor, where the gas is at high temperature. Minor changes in gas composition occur due to secondary reactions of methane and carbon. As the reaction rates are relatively low, the methane content is higher than would be expected from equilibrium. During the soaking phase, a portion of the carbon also disappears by reactions with CO2 and steam. However, some carbon is always present in the product gas from the reactor in a quantity equivalent to about 1-3% wt of the oil feed. Natural gas feedstock produces only a very small amount of residual carbon i.e., about 0.02% wt of the gas feedstock. 

Values illustrating product yields and gas compositions from isothermal experiments are shown in Table II. The yield data shown were obtained after a reaction period of two hours at a reaction temperature of 450°C. The gas and liquid yields are higher and the residue yield is lower when a catalyst is present. The gas compositions with and without catalyst are fairly similar. However 13C NMR analyses showed that the liquid products obtained in the catalyzed experiment have a higher aromatic content than those formed in the absence of the catalyst. 

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