Superheated Ethane

The reaction is highly endothermic, so it is favored at higher temperatures and lower pressures. Superheated steam is used to reduce the partial pressure of the reacting hydrocarbons (in this reaction, ethane). Superheated steam also reduces carbon deposits that are formed by the pyrolysis of hydrocarbons at high temperatures. For example, pyrolysis of ethane produces carbon and hydrogen ... 

Carbon dioxide and water are the most commonly used SCFs because they are cheap, nontoxic, nonflammable and environmentally benign. Carbon dioxide has a more accessible critical point (Table 6.13) than water and therefore requires less complex technical apparatus. Water is also a suitable solvent at temperatures below its critical temperature (superheated water). Other fluids used frequently under supercritical conditions are propane, ethane and ethylene. 

FIGURE 1.3-2 Composition dependence of fogacity coefficient of hydrogen sulfide in binary mixtures with ethane at 300 K. Curves labeled V are for superheated vapors at 15 har. those labeled L are for subcooled liquids at 50 bsr, Ail curves are computed from the Soave-Redlich-Kwong equation, with values of interaction parameter kla as shown. 

Hydrocarbon feedstocks such as ethane, propane, butane and naphtha are sent together with superheated steam to the cracking fiimace, where endothermic reactions occm at high... 

Steam reforming consists of reacting natural gas (i.e., methane) or, to a lesser extent, other light hydrocarbons (e.g., ethane or propane), depending on availabihty at the plant location, with superheated steam in the presence of a suitable catalyst. The overall chemical reactions for methane and for a general hydrocarbon are ... 

Subsequently, Peters et al. continued these investigations. Their natural gas feed contained, besides methane, ethane, propane and butane, also 0.11 vol.% pentane and 0.1 vol.% higher hydrocarbons. Feed pre-heating, water evaporation and superheating to a temperature between 350 and 400 ° C was supplied with energy from the hot off-gas of a catalytic burner. The pre-reformer was then operated at temperatures between 536 and 785 °C. Around 20% methane conversion was achieved in the reactor, while the ethane conversion ranged between 40 and 50%. 

Substances considered in a compilation of the thermodynamic properties of refrigerants include hydrogen, parahydrogen, helium, neon, nitrogen, air, oxygen, argon, carbon dioxide, hydrocarbons (e.g. methane, ethane, propane, butane, isobutane, ethylene, and propene), and fluoro-and fluoro-chloro-hydrocarbons. Properties listed include those for the liquid and saturated vapour, superheated vapour, and unsaturated vapour. In addition, pressure-enthalpy, and in some instances pressure-entropy, diagrams are provided. 

Let us now look more closely at an element of superheated liquid mixture at the liquid/vapour interface during surface evaporation. The spent Uquid, after evaporating a methane rich vapour, has increased in density due to both evaporative latent heat of cooling and an increase in more dense ethane composition. The spent element is convectively unstable and sinks away from the surface. 

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