Ethane Ethylene

C2 fraction without acetylene to ethylene/ethane separation... 

Heat Pumps. Because of added capital and complexity, heat pumps are rarely economical, although they were formerly commonly used in ethylene/ethane and propylene/propane spHtters. Generally, the former spHtters are integrated into the refrigeration system the latter are driven by low level waste heat, cascading to cooling water. 

A dephlegmator process can be used to recover ethylene—ethane and heavier hydrocarbons from fluid catalytic cracking (FCC) unit off-gas (Fig. 7). Pretreated feed gas is cooled to about 230 K and then further cooled and rectified in a dephlegmator to recover 90 to 98% of the ethylene, 99 % of the... 

The dephlegmator process recovers a substantially higher purity C2+ hydrocarbon product with 50—75% lower methane content than the conventional partial condensation process. The C2+ product from the cryogenic separation process can be compressed and further separated in a de-ethanizer column to provide a high purity C3+ (LPG) product and a mixed ethylene—ethane product with 10—15% methane. Additional refrigeration for the deethanization process can be provided by a package Freon, propane or propylene refrigeration system. 

As discussed in Sec. 4, the icomplex function of temperature, pressure, and equilibrium vapor- and hquid-phase compositions. However, for mixtures of compounds of similar molecular structure and size, the K value depends mainly on temperature and pressure. For example, several major graphical ilight-hydrocarbon systems. The easiest to use are the DePriester charts [Chem. Eng. Prog. Symp. Ser 7, 49, 1 (1953)], which cover 12 hydrocarbons (methane, ethylene, ethane, propylene, propane, isobutane, isobutylene, /i-butane, isopentane, /1-pentane, /i-hexane, and /i-heptane). These charts are a simplification of the Kellogg charts [Liquid-Vapor Equilibiia in Mixtures of Light Hydrocarbons, MWK Equilibnum Con.stants, Polyco Data, (1950)] and include additional experimental data. The Kellogg charts, and hence the DePriester charts, are based primarily on the Benedict-Webb-Rubin equation of state [Chem. Eng. Prog., 47,419 (1951) 47, 449 (1951)], which can represent both the liquid and the vapor phases and can predict K values quite accurately when the equation constants are available for the components in question. 

Carbon monoxide, methane, ethylene, ethane, ethylene dichloride, aromatic solvent... 

The Cj plus bottoms from the demethanizer then go to the deethanizer. A propylene-propane bottoms product containing 90-92% propylene is obtained which may either be sold, used directly as propylene- 90, or further purified. The ethylene-ethane overhead from the deethanizer is separated in the splitter tower yielding a 99.8% overhead ethylene product at -25°F. The ethane bottoms at -l-18°F may either be sent to fuel gas or used as feed to an ethane cracking furnace. Overall ethylene recovery in these facilities is about 98%. The product is of very high purity with less than 50 parts per million of non-hydrocarbon contaminants and a methane plus ethane level below 250 ppm. 

Analogy between the Delocalized Orbitals of a Hydrocarbon Skeleton (Ethylene, Ethane, Allene, Propane, etc.) and the T Delocalized Orbitals of Conjugated Chains... 

Alkanes and Alkenes. For this study, C150-1-01 and C150-1-03 were tested under primary wet gas conditions with ethylene, ethane, propylene, and propane being added to the feed gas. This study was made in order to determine whether these hydrocarbons would deposit carbon on the catalyst, would reform, or would pass through without reaction. The test was conducted using the dual-reactor heat sink unit with a water pump and vaporizer as the source of steam. All gas analyses were performed by gas chromatography. The test was stopped with the poisons still in the feed gas in order to preserve any carbon buildup which may have occurred on the catalysts. 

Propylene Acetylene Propane Hydrogen Ethylene Ethane... 

Figure 4. Effect of methane conversion for 1=5 mA on ethylene, ethane and total Cg hydrocarbon selectivity and yield. Lines from kinetic model discussed below. Solid lines CgH j and C2Hg Dashed lines C2...

Figure 5. Effect of adsorbent mass in the molecular sieve trap on the ethylene, ethane and total C2 selectivity at a fixed methane conversion of 15%. Recirculation flowrate 220 cm3 STP/min...

The spontaneously explosive interaction of dichlorine oxide with methane, ethane, propane, ethylene or butadiene was investigated at 50-150°C. Self-heating occurs with ethylene, ethane and propane mixtures. 

More recently the flash photolysis of diethyl mercury has been re-investigated by Fischer and Mains92. At 1.54 torr and 24 °C the major products are butane (36 %), ethylene (32 %), ethane (22 %), propane (6 %) and hydrogen (4 %). Only traces of methane were detected. The addition of perfluorodimethylcyclo-butane vapour did not alter the extent of photolysis, but the butane yield increased approximately 25 % while the yield of ethylene, ethane, hydrogen and propane all decreased. The change in product distribution occurred as the inert gas pres-... 

Photolytic. The vacuum UV photolysis (X = 147 nm) and y radio lysis of ethylenimine resulted in the formation of acetylene, methane, ethane, ethylene, hydrogen cyanide, methyl radicals, and hydrogen (Scala and Salomon, 1976). Photolysis of ethylenimine vapor at krypton and xenon lines yielded ethylene, ethane, methane, acetylene, propane, butane, hydrogen, ammonia, and ethylene-imino radicals (Iwasaki et al, 1973). 

Ethyleneplatinous Chloride. Flynn and Hulburt (55) have shown that when toluene or acetone solutions of ethyleneplatinous chloride are reacted with hydrogen at temperatures below —10°, in the presence of an excess of ethylene, ethane may be formed without accompanying deposition of metalUc platinum. The reaction under these conditions appears to be homogeneous, and the following mechanism, which, however, requires substantiation, has been proposed ... 

Selwood (100,101) has also employed this technique to study the chemisorption of ethylene, ethane, benzene, and cyclohexane on supported nickel catalysts. Among the new information and important conclusions derived from these measurements are the following ... 

Acetylene is less stable thermodynamically relative to ethylene than ethylene is to ethane because AH for acetylene— ethylene is -177kJ/mol, while for ethylene— ethane it is -137kJ/mol. Therefore acetylene is more easily hydrogenated and the process can be stopped at the ethylene stage. In general, hydrogenation of alkynes can be stopped at the alkene stage. 

The preferential release of C3 and C4 as the smallest fragments is a relative matter ethylene, ethane, and methane can be produced under more drastic experimental conditions, and are produced in small amounts in ordinary catalytic cracking. The conventional process operates under conditions which maximize the desired type of splitting to the more useful gaseous products. To demonstrate the application of theory to practice, the predicted and experimental curves for the cracking of cetane (7) are shown in Figure 3. 

Fig. 5. Adsorption isotherms and composition of the gas phase for the adsorption of ethylene on (a) rhodium—silica and (b) palladium—silica at 20°C. o, Total molecules adsorbed , ethylene , ethane.

Catalyst Temp. (°C) D2/olefin Conversion (%) Ethylenes Ethanes ... 

In the absence of oxygen, about 82 peaks of hydrocarbon products were observed in the gas chromatogram, which showed that the main products consisted of C6 hydrocarbons (Table IV), hydrogen, methane, acetylene, ethylene, ethane, methylacetylene, allene, propane, 1-butene, and butadiene. 

Studiengesselschaft Kohle m.b.H. (2) reported the effect of temperature on solubility level in supercritical gas. The solubility is highest within 20 K of the critical temperature and decreases as temperature is raised to 100 K above the critical temperature. At temperatures near the critical temperature, a sharp rise in solubility occurs as the pressure is increased to the vicinity of the critical pressure and increases further as the pressure is further increased. Less volatile materials are taken up to a lesser extent than more volatile materials, so the vapor phase has a different solute composition than the residual material. There does not seem to be substantial heating or cooling effects upon loading of the supercritical gas. It is claimed that the chemical nature of the supercritical gas is of minor importance to the phenomenon of volatility amplification. Ethylene, ethane, carbon dioxide, nitrous oxide, propylene, propane, and ammonia were used to volatilize hydrocarbons found in heavy petroleum fractions. 

Figure 5.14. Selectivity dependence of alkylation on the ethylene-alkane ratio for the following reactions ethylene + methane ( ), ethylene + ethane (o), ethylene + propane (A), ethylene + n-hutane ( ).

Fig. 8.10 (a) Response of semiconductor gas sensors toward ethylene, ethane... 

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