Addition Of Ethane Research Articles

Synthesis Gas Production from Partial Oxidation of Methane with Air in AC Electric Gas Discharge

In this study, synthesis gas production in an AC electric gas discharge of methane and air mixtures at room temperature and ambient pressure was investigated. The objective of this work was to understand how the CH4/O2 feed mole ratio, ethane added, diluent gas, residence time, input power, applied frequency, and waveform, affected methane and oxygen conversions, product selectivities, and specific energy consumption. Methane and oxygen conversions increased with input power but decreased with increasing CH4/O2 feed mole ratio, flow rate, and gap distance. The experiments were performed at the frequency and power in the range of 200-700 Hz and 8-14 W, respectively, while the residence times were varied from 0.06 to 0.46 s. This study confirms that active oxygen is an important factor in enhancing methane conversion and energy efficiency in a discharge reactor. Ethane is the primary product that forms at short residence times and low energies. Methane conversion dropped dramatically but oxygen conversion increased with addition of ethane to the feed gas. Sinusoidal and square waveforms gave negligibly different results. Current was constant with varying CH4/O2 ratio and flow rate, but increased with increasing power and with decreasing gap distance and frequency. It was shown that the best condition was at 300 Hz and at the highest power used in each condition, since the maximum methane and oxygen conversions and synthesis gas selectivity as well as lowest specific energy consumption were found both with and without ethane in the feed gas. The minimum specific energy consumption, found at 300 Hz, were 21 and 14 eV/mc for the CH4/air system and the CH4/air/C2H6 system, respectively. When studying the effect of residence time by varying the flow rate, the minimum energy consumption of 21 eV/mc was found at 0.12 and 0.23 s. For any given input power or frequency, the CH4/air system had a higher specific energy consumption than the CH4/air/C2H6 system. Less energy was consumed to convert methane under the plasma environment with nitrogen as a diluent compared to helium, indicative of a third body effect.

Activation of ethane in the metathesis reaction on silica-supported tantalum hydride: a quantum-chemical study

The structures of the (H4Si2O5)O2TaR and (H4Si2O5)O2TaRH2 clusters (R = H, Me, or Et), which model the main structural units of the catalytic cycle of the ethane metathesis on silica-supported tantalum hydride, were studied using the density functional theory at the B3LYP level. Even at high temperatures, activation of ethane cannot proceed via a two-step mechanism involving the oxidative addition of ethane and reductive elimination of hydrogen to form pentavalent tantalum compounds.

The influence of inert gases on the high-pressure phase equilibria of EVA-copolymer/vinyl acetate/ethylene mixtures

Using a high-pressure autoclave the cloud point pressures of supercritical poly(ethylene-co-vinyl acetate) copolymer (EVA-copolymer) solutions were measured in the temperature range of 393–493 K. In this paper, we present the results for quasi-ternary mixtures consisting of a EVA-copolymer, ethylene and an inert compound (helium, nitrogen, CO 2, methane, ethane, propane, n-butane). Also the quasi-quaternary system EVA-copolymer/ethylene/vinyl/acetate/nitrogen is discussed. Experiments were carried out at vinyl acetate:ethylene mass ratios of 0, 1:3, 1:1 and 3:1. In all cases, helium, nitrogen, carbon dioxide and methane lowered the copolymer solubility. The antisolvent effect decreases in the order helium>nitrogen>methane>CO 2. Propane and n-butane were found to act as cosolvents, whereas the addition of ethane had no significant influence.

A Laboratory Study on Near-Miscible CO2 Injection in Steelman Reservoir

Abstract Miscible flooding is considered unsuitable for some reservoirs in southeast Saskatchewan because of high C)2 minimum miscibility pressure or operating pressure constraints. Therefore, the effectiveness of near-miscible C)2 injection was assessed for the Steelman reservoir in a laboratory study. The minimum miscibility pressures (MMP) were estimated for Steelman reservoir fluids with pure C)2 and C)2-hydrocarbon gas mixtures, the partially flashed reservoir fluids and the dead oils with pure C)2. The results of MMP studies demonstrated (1) addition of ethane or propane can reduce C)2 MMP greatly; and (2) achieving a miscible C)2 flood in the Steelman reservoir could be possible at a lower operating pressure than the measured C)2 MMP, by partially depleting the reservoir. Asphaltene flocculation tests showed that, after the onset point, flocculation increased linearly with gas concentration, but that the presence of brine had a negligible effect. Three tertiary C)2 coreflood tests were conducted with Steelman reservoir fluids at the reservoir temperature. These results showed that the microscopic displacement efficiency during the C)2 injection stage improved with the operating pressure in the near-miscible region, but no dramatic change in oil recovery was observed with a change in operating pressure. Introduction The Steelman pool, located about 200 km southeast of Regina, Saskatchewan, was discovered in 1954. Covering approximately 370 km2, the field was estimated to contain over 134 million m3 of light oil in the Frobisher and Midale beds located at a depth of about 1,400 m. Most of the reservoirs in the Midale beds, which contain about 83﹪ of the reserves of the pool, have been under waterflood for over 20 years and have nearly reached the estimated production limit by primary and waterflood(1). For achieving additional oil recovery and consequent financial benefits, the development of tertiary enhanced oil recovery (EOR) techniques, such as C)2 flooding, is essential. Miscible C)2 flooding is a proven enhanced oil recovery technique(2). Over the last decade, C)2 injection has become the leading EOR process for light oil(3). In Canada, the industry interest in C)2 flooding is evidenced by Shell Canada's C)2 pilot tests(4, 5), a miscible C)2 flood at Joffre field in Alberta(6), and the implementation of PanCanadian's Weyburn C)2 injection project(7). Additional field applications are expected to be initiated in southeast Saskatchewan and other regions when C)2 sources are available. Miscible C)2 displacement offers the greatest oil recovery potential, but it can only be achieved at a pressure greater than a certain minimum referred to as the minimum miscibility pressure (MMP). The effect of solution gas on the development of miscibility is not well understood, as is reflected by the lack of a consensus in the literature. Rathmell et al.(8) found that C)2 MMP is related to the volatile and intermediate fractions of the oil. Yelling and Metcalfe(9) found from their experimental study that, for a saturated reservoir oil, areal variation in gas-oil ratio (GOR) will result in an areal variation in the C)2 MMP. They pointed out that the C)2 MMP determined for a pilot area may not apply to the rest of the field.

Transition metal-catalyzed alkane dehydrogenation

A computational study of ethane dehydrogenation by the 14-electron complex Ir(PH 3) 2H ( 1) is presented. The first step is CH oxidative addition of ethane to 1. The intrinsic reaction coordinate (IRCs) for ethane CH oxidative addition are consistent with an experimental trajectory derived from analysis of the crystal structures of agostic complexes. Ethane binds to 1 as strongly as, if not stronger than, methane. However, calculation of the IRC suggests that for ethane, unlike methane, an alkane adduct of 1 does not lie along the path to CH oxidative addition. The product of oxidative addition is a non-agostic Ir III-ethyl complex. Oxidative addition is followed by β-H transfer to yield an Ir III-ethylene complex. Following the IRC for β-H transfer from the transition state towards reactants shows the reactant to be an agostic Ir III-ethyl isomer, ≈4 kcal mol − lower in energy than its non-agostic isomer (i.e., the product of oxidative addition). Thus, calculations support experimental suggestions about the importance of agostic interactions in β-hydride transfer (and the microscopic reverse, olefin insertion into MH bonds). After olefin dissociation, complex 1 is regenerated by H 2 reductive elimination to complete the catalytic cycle. The product of H 2 reductive elimination from the catalyst is an η 2-dihydrogen complex. The present calculations support the experimental inference that the HH distance remains constant along the IRC (at ≈ 0.82 Å) until very close to the transition state for oxidative addition, after which it undergoes rapid lengthening and scission.

Reactions of Fe +n clusters ( n = 2–11) with C 6H 6 and C 6D 6. Ligand isomerization in the benzene precursor ion Fe 4(C 2H 2) +3

Even though Fe + 4 clusters in the gas phase have been demonstrated to be able to induce the cylotrimerization of added C 2H 2 ligands to benzene, the precursor ion Fe 4(C 2H 2) + 3 has not yet been structurally characterized. To improve our understanding of this type of ion, we compare the products obtained by the direct reaction of benzene with bare Fe + n clusters ( n = 2–11) to those obtained by dehydrogenative addition of ethane. Additional mass spectrometric studies such as collision-induced dissociation (CID) and thermoneutral ligand exchange with C 6D 6 suggest that the reaction of C 2H 4 with Fe + 4 produces at least two types of structural isomers, with a performed benzene molecule existing only in one of them (Fe 4C 6H + 6).

The oxidative coupling of methane with cofeeding of ethane

The oxidative coupling of methane with cofeeding of ethane was investigated experimentally both in the absence and in the presence of a Sn/Li/MgO catalyst. Cofeeding ethane in the absence of catalyst results in a higher total radical concentration, explaining the strong increase of the observed feed conversions. The hydrogen-peroxy radical-concentration increase is more pronounced than the corresponding methyl radical concentration increase, resulting in a lower selectivity. The combined effect of feed conversion and selectivity is beneficial for inlet ethane-to-methane ratios lower than 4 mol%. Ethane cofeeding results in a slight increase of the oxygen conversion in the presence of a Sn/Li/MgO catalyst. This can be accounted for by a mechanism in which both the hydrogen abstraction from the hydrocarbon and the regeneration of the active sites are kinetically significant. The corresponding decrease of methane conversion results from competition between methane and the more reactive ethane for these sites. The addition of ethane does not result in a beneficial effect on conversions to ethane or C 2.

Effect of ethane addition on propane pyrolysis

AbstractPyrolysis of propane/argon mixture in the presence of trace quantities (0.1% and 0.9%) of ethane was investigated at reflected shock wave temperatures between 1200 and 2000K. Traces of ethane accelerated propane decomposition at high temperature. However, increase in the quantity of ethane added to propane/argon mixture did not result in the same increase of its accelerating influence. Ethylene, methane and acetylene were the main hydrocarbon reaction products, with small quantities of propylene and ethane detected only at lower temperatures. Below 1500K, addition of ethane slightly enhanced the yields of ethylene and methane at the expense of propylene and ethane respectively. The selectivity for acetylene increased with increasing temperature and with the decline of those for the other products. For none of the products, did the presence of ethane alter the relationship between product formation rates and temperature. The influence of ethane addition on propane pyrolysis at high temperatures was explained in terms of increased radical concentrations, especially hydrogen atoms and vinyl radicals, formed at high conversions. These accounted for the rapid acceleration of propane decomposition and the high yield of acetylene at high temperatures.

Addition of ethane to slowly reacting mixtures of hydrogen and oxygen at 500°C

Addition of traces of hydrocarbons to slowly reacting mixtures of H2+ O2 at 500°C can give information first on the reactions of H and OH with the hydrocarbon, and secondly, on the subsequent reactions of the alkyl radical produced. By combining with lower temperature studies, a value of k(OH + C2H6)= 8.7 × 1010 exp(–3520/RT) in 1. mol s, cal units, is obtained. The value obtained for H + C2H6 agrees closely with previous estimates. The analysis of reaction products indicates that 96 ± 2 % of C2H5 radicals react with O2 to give C2H4, and that only very small amounts of CH3CHO and C2H4O are produced. From these relative yields, the overall velocity constants for formation of CH3CHO and C2H4O can be obtained.

Role of OH and HO2 radicals in the slow combustion of mixtures of methane, ethane and ethylene

The combustion of methane is facilitated by the addition of ethane. The induction period is reduced and the maximum rate of combustion is increased. This effect is due to the formation of ethylene which in turn forms formaldehyde. Relative rate constants are deduced for the rates of reaction of hydroxyl radicals with methane, ethane and ethylene over the temperature range 461°C to 525°C. Thus, at 500°C hydroxyl radicals react 5 times as fast with ethylene and 10 times as fast with ethane as with methane. Less accurate rate constant ratios are obtained for the reaction of hydroperoxyl radicals with carbon monoxide, ethane and ethylene.

Synthesis and properties of polychloro dialkyl sulfides

1. A study was made of the addition of ethane- and 2-chlor-1-propane-sulfenyl chlorides to 3,3,3-trichlo-ropropene. The direction of addition was contrary to Markovnikov's rule. 2. 1,1,1,3-Tetrachloro-2-propanesulfenyl chloride readily adds to propene, isobutene, and styrene with formation of polychloro dialkyl sulfides.

PRELIMINARY STUDY OF PHOTOCHEMICAL BEHAVIOR IN THE SYSTEM NITROGEN DIOXIDE – ETHANE

The addition of ethane to nitrogen dioxide either during exposure to radiation transmitted by pyrex, or afterwards, reduces the amount of oxygen formed. At room temperature this is apparently due to the effectiveness of ethane in promoting the reverse reaction of nitric oxide and oxygen to form nitrogen dioxide. At temperatures over 100° there is a reaction which uses oxygen atoms produced in the primary process. Nitroethane (or nitrosoethane) is formed along with carbon monoxide, carbon dioxide, and some methane. The results suggest that acetaldehyde is an intermediate, but acetaldehyde could not be detected because it would react thermally with nitrogen dioxide. It is not possible to give a complete explanation of the results, but suggestions can be made which might form the basis for later work.