Propane energy density

Figure 9.3. Energy densities of various alternative fuels (LHY) (LPG 50% propane, 50% butane natural gas 83% methane).

The first generation of research involving surfactants in SCFs addressed water/oil (w/o) microemulsions (Fulton and Smith, 1988 Johnston et al., 1989) and polymer latexes (Everett and Stageman, 1978) in ethane and propane (Bartscherer et al., 1995 Fulton, 1999 McFann and Johnston, 1999). This work provided a foundation for studies in C02, which has modestly weaker van der Waals forces (polarizability per volume) than ethane. Consequently, polymers with low cohesive energy densities and thus low surface tensions are the most soluble in C02 for example, fluor-oacrylates (DeSimone et al., 1992), fluorocarbons, fluoroethers (Singley et al., 1997), siloxanes, and to a lesser extent propylene oxide. Since C02 is... 

Another application of rhodium carbenoid chemistry relates to the synthesis of strained-ring nitro compounds as high energy-density materials. Nitrocyclo-propanes are the simplest members of this class of compounds and catalyzed additions of a nitrocarbene to an olefin have only been described recently [40], Detailed studies have shown that the success of the reaction is, as expected, dependent on both the alkene and the nitrodiazo precursor. Consistently with the electrophilic character of rhodium carbenoids, only electron-rich alkenes are cyclopropanated. The reaction has been extended to the synthesis of nitrocyclo-propenes but the yields are good for terminal acetylenes only [41]. 

Pressure effects on surfactant systems containing conventional liquid alkanes have not often been studied because of the very low compressibility of liquids. Conflicting results have been reported [38-40]. It is likely that the changes in cohesive energy density (solubility parameter) of the phases over the pressure ranges used were too low to produce definitive trends in phase behavior. The solubility parameter of compressed liquid propane, however, is moderately adjustable with pressure, and therefore a propane-brine-AOT system could be expected to show pressure-driven phase transitions [20,22,41]. 

Since DME characteristics are similar to those of liquefied petrol gas (LPG), it can be used in typical LPG applications, e.g. power generation, propellants, domestic cooking fuels or automotive fuels. If DME is employed as admixture, LPG properties are not significantly affected up to a DME content of around 20%. Compared to LPG, the cetane number is much higher (55-60 in contrast to 5 and 10 for propane and butane) and DME is, in principle, a suitable fuel for diesel engines. However, DME can not be blended with fossil diesel and its energy density is much lower, so that engines have to be adapted. 

Natural gas is composed mostly of methane (85 to 90%) with only small amounts of ethane, propane, and butane. It is almost free of harmful contaminants and can bum efficiently, and may release only small amounts of harmful gases and vapors. However, the low energy density of natural gas retards its wide application as automobile fuel. One liter of petroleum on combustion produces about 3.5 x 10 KJ... 

Figure 6.7. The percentage destruction of 100 ppm propane ( ) and propene ( ) in an atmospheric air stream using a surface discharge plasma reactor as a function of plasma energy density. Adapted from. ...

Figure 6.8. Effect of catalyst on 100 ppm propane (left hand panel) and propene (right hand panel) destruction in air as a function of plasma energy density, plasma only (no catalyst), Ti02, y-Al203 and NaA.

The use of plasma catalysis can increase the energy efficiency of the abatement process for both propane and propene, but the effect of the addition of a catalyst is modest in the case of propane processing but quite dramatic for propene, as shown in Fig. 6.8, where 100% destruction can be achieved at a plasma energy density of 20 J litre The equivalent destruction for propene in the absence of a catalyst at this energy would be only 50%. In both cases, the most effective material was found to be y-alumina which may result from reactions involving surface OH species as was seen for DCM and also the effectiveness of y-alumina as an absorbent which will increase the processing time within the plasma. 

Fuel cell performance was studied by Kronemayer et al. (2007) as a function of a number of factors the fuel/air ratio in the gas mixture fed to the burner, the distance of the anode from the tip of the flame, and the temperature of the fuel cell itself. Methane, propane, and butane were used as fuels in these experiments. Values of the specific energy density of up to 120 mW/cm were attained under optimum conditions. 

The numerical jet model [9-11] is based on the numerical solution of the time-dependent, compressible flow conservation equations for total mass, energy, momentum, and chemical species number densities, with appropriate in-flow/outfiow open-boundary conditions and an ideal gas equation of state. In the reactive simulations, multispecies temperature-dependent diffusion and thermal conduction processes [11, 12] are calculated explicitly using central difference approximations and coupled to chemical kinetics and convection using timestep-splitting techniques [13]. Global models for hydrogen [14] and propane chemistry [15] have been used in the 3D, time-dependent reactive jet simulations. Extensive comparisons with laboratory experiments have been reported for non-reactive jets [9, 16] validation of the reactive/diffusive models is discussed in [14]. 

Grillet et al. (1991) studied mechanical properties of epoxy networks with various aromatic hardeners. It is possible to compare experimental results obtained for networks exhibiting similar Tg values (this eliminates the influence of the factor Tg — T). For instance, epoxy networks based on flexible BAPP (2-2 - bis 4,4-aminophenoxy phenyl propane) show similar Tg values ( 170°C) to networks based on 3-3 DDS (diamino diphenyl sulfone). However, fracture energies are nine times larger for the former. These results constitute a clear indication that the network structure does affect the proportionality constant between ay and Tg — T. Although no general conclusions may be obtained, it may be expected that the constant is affected by crosslink density, average functionality of crosslinks and chain... 

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