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1.
In this research, the reforming of simulated natural gas containing a high CO2 content under AC non-thermal gliding arc discharge with partial oxidation was conducted at ambient temperature and atmospheric pressure, with specific regards to the concept of the direct utilization of natural gas. This work aimed at investigating the effects of applied voltage and input frequency, as well as the effect of adding oxygen on the reaction performance and discharge stability in the reforming of the simulated natural gas having a CH4:C2H6:C3H8:CO2 molar ratio of 70:5:5:20. The results showed marked increases in both CH4 conversion and product yield with increasing applied voltage and decreasing input frequency. The selectivities for H2, C2H6, C2H4, C4H10, and CO were observed to be enhanced at a higher applied voltage and at a lower frequency, whereas the selectivity for C2H2 showed an opposite trend. The use of oxygen was found to provide a great enhancement of the plasma reforming of the simulated natural gas. For the combined plasma and partial oxidation in the reforming of CO2-containing natural gas, air was found to be superior to pure oxygen in terms of reactant conversions, product selectivities, and specific energy consumption. The optimum conditions were found to be a hydrocarbons-to-oxygen feed molar ratio of 2/1 using air as an oxygen source, an applied voltage of 17.5 kV, and a frequency of 300 Hz, in providing the highest CH4 conversion and synthesis gas selectivity, as well as extremely low specific energy consumption. The energy consumption was as low as 2.73 × 10−18 W s (17.02 eV) per molecule of converted reactant and 2.49 × 10−18 W s (16.60 eV) per molecule of produced hydrogen.  相似文献   

2.
The effect of stage number of multistage AC gliding arc discharge reactors on the process performance of the combined reforming and partial oxidation of simulated CO2-containing natural gas having a CH4:C2H6:C3H8:CO2 molar ratio of 70:5:5:20 was investigated. For the experiments with partial oxidation, either pure oxygen or air was used as the oxygen source with a fixed hydrocarbon-to-oxygen molar ratio of 2/1. Without partial oxidation at a constant feed flow rate, all conversions of hydrocarbons, except CO2, greatly increased with increasing number of stages from 1 to 3; but beyond 3 stages, the reactant conversions remained almost unchanged. However, for a constant residence time, only C3H8 conversion gradually increased, whereas the conversions of the other reactants remained almost unchanged. The addition of oxygen was found to significantly enhance the process performance of natural gas reforming. The utilization of air as an oxygen source showed a superior process performance to pure oxygen in terms of reactant conversion and desired product selectivity. The optimum energy consumption of 12.05 × 1024 eV per mole of reactants converted and 9.65 × 1024 eV per mole of hydrogen produced was obtained using air as an oxygen source and 3 stages of plasma reactors at a constant residence time of 4.38 s.  相似文献   

3.
Polyimide membranes derived from 6FDA-DAM:DABA and 6FDA-6FpDA:DABA copolymers have been used to separate 50/50 CO2/CH4 mixtures and multicomponent synthetic natural gas mixtures at 35 °C and feed pressures up to 55 atm. For 6FDA-DAM:DABA 2:1 membranes the effects of thermal annealing and covalent crosslinking are decoupled with respect to effects on permeabilities and selectivity. Crosslinking at 295 °C with 1,4-butylene glycol and 1,4-cyclohexanedimethanol increases CO2 permeabilities by factors of 4.1 and 2.4, respectively, at 20 atm feed pressure, without a loss in selectivity, relative to crosslinking at 220 °C. Thermal annealing and crosslinking also reduce CO2 plasticization effects. Crosslinking of DABA-containing copolymers, therefore, can produce membranes with tunable transport properties that offer significantly higher performance with better plasticization-resistance than that reported in the literature for the commercial polymers Matrimid® and cellulose acetate for CO2 removal from natural gas mixtures. Separation of complex mixtures containing CO2, CH4, C2H6, C3H8, and C4H10 or toluene results in a significant decrease of the CO2 permeability, but only a moderate decrease in the CO2/CH4 selectivity.  相似文献   

4.
Adsorption of each component of natural gas on adsorbent prepared from petroleum coke was studied. At 25 °C and 3.5 MPa, adsorption capacity of the components of natural gas are as follows: C3H8, H2S(0.980) > CO2(0.691) > C2H6(0.160) > CH4(0.136) > N2(0.096) (g/g). For natural gas, adsorption capacity is 145.2 (mL/mL) and delivery capacity is 105.7 (mL/mL). One equation between adsorption capacity and boiling point of adsorbed gas was firstly generalized. The adsorption capacity of different component like O2, N2, CH4, C2H6, CO2, H2S on adsorbents were predicted using the equation. The results fit well with the experimental data. The equation has significance in predicting the adsorption capacity for any component of natural gas. Charge-discharge tests were conducted 10 times, the result indicates that natural gas has significantly worse reversibility in adsorption and desorption in the adsorbent than that of CH4. The contents of the components after 10 charge-discharge show that the adsorption capacity drop of natural gas is due to the irreversible adsorption of heavy or polar components like C3H8, H2S.  相似文献   

5.
Thermal internal energy gaps, ΔE s−t; enthalpy gaps, ΔH s−t; Gibbs free energy gaps, ΔD s−t, between singlet (s) and triplet (t) states of R2C4H2M (M = C, Si, and Ge) were calculated at B3LYP/6-311++G** level of theory. The ΔG s−t of R2C4H2C was increased in the order (in kcal/mol): R = −CH3 (−10.51) > −H (−9.59) > i-Pr (−9.51) > t-Bu (−8.98). While, the ΔG s−t of R2C4H2Si and R2C4H2Ge were increased in the order (in kcal/mol): −CH3 (17.01) > i-Pr (15.30) > −H (15.26) > t-Bu (14.35) and -H (22.79) > −CH3 (22.69) > i-Pr (21.66) > t-Bu (21.01), respectively.  相似文献   

6.
A novel 3D metal‐organic framework BSF‐1 based on the closo‐dodecaborate cluster [B12H12]2? was readily prepared at room temperature by supramolecular assembly of CuB12H12 and 1,2‐bis(4‐pyridyl)acetylene. The permanent microporous structure was studied by X‐ray crystallography, powder X‐ray diffraction, IR spectroscopy, thermogravimetric analysis, and gas sorption. The experimental and theoretical study of the gas sorption behavior of BSF‐1 for N2, C2H2, C2H4, CO2, C3H8, C2H6, and CH4 indicated excellent separation selectivities for C3H8/CH4, C2H6/CH4, and C2H2/CH4 as well as moderately high separation selectivities for C2H2/C2H4, C2H2/CO2, and CO2/CH4. Moreover, the practical separation performance of C3H8/CH4 and C2H6/CH4 was confirmed by dynamic breakthrough experiments. The good cyclability and high water/thermal stability render it suitable for real industrial applications.  相似文献   

7.
Raw natural gas is a complex mixture comprising methane, ethane, other hydrocarbons, hydrogen sulfide, carbon dioxide, nitrogen, and water. For sour gas fields, selective and energy‐efficient removal of H2S is one of the crucial challenges facing the natural‐gas industry. Separation using nanoporous materials, such as zeolites, can be an alternative to energy‐intensive amine‐based absorption processes. Herein, the adsorption of binary H2S/CH4 and H2S/C2H6 mixtures in the all‐silica forms of 386 zeolitic frameworks is investigated using Monte Carlo simulations. Adsorption of a five‐component mixture is utilized to evaluate the performance of the 16 most promising materials under close‐to‐real conditions. It is found that depending on the fractions of CH4, C2H6, and CO2, different sorbents allow for optimal H2S removal and hydrocarbon recovery.  相似文献   

8.
Surface Compounds of Transition Metals. XXX. Fischer-Tropsch Analogous Reactions of CO/H2 and CO2/H2 on Surface Chromium(II) Surface chromium(II)/silicagel catalyzes the reduction of CO and CO2 by hydrogen to CH4, C2H6 and C3H8. The catalyst is partially desactivated by this reaction, but a permanent activity of ca. 30% remains. – The reaction can be formulated via the sequence formaldehyde complex → <CH2>-complex → alkane. If cycloalkenes or chlorobenzene are added simultaneously, these scavenger molecules are methylated by <CH2>.  相似文献   

9.
The solubilities of He, H2, N2, O2, CO2, CH4, C2H6, C3H8, and n‐C4H10 were determined at 35°C and pressures up to 27 atmospheres in a systematic series of phase separated polyether–polyamide segmented block copolymers containing either poly(ethylene oxide) [PEO] or poly(tetramethylene oxide) [PTMEO] as the rubbery polyether phase and nylon 6 [PA6] or nylon 12 [PA12] as the hard polyamide phase. Sorption isotherms are linear for the least soluble gases (He, H2, N2, O2, and CH4), convex to the pressure axis for more soluble penetrants (CO2, C3H8, and n‐C4H10) and slightly concave to the pressure axis for ethane. These polymers exhibit high CO2/N2 and CO2/H2 solubility selectivity. This property appears to derive mainly from high carbon dioxide solubility, which is ascribed to the strong affinity of the polar ether linkages for CO2. As the amount of the polyether phase in the copolymers increases, gas solubility increases. The solubility of all gases is higher in polymers with less polar constituents, PTMEO and PA12, than in polymers with more polar PEO and PA6 units. CO2/N2 and CO2/H2 solubility selectivity, however, are higher in polymers with higher concentrations of polar repeat units. The sorption data are complemented with physical characterization (differential scanning calorimetry, elemental analysis, and wide angle X‐ray diffraction) of the various block copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2463–2475, 1999  相似文献   

10.
Ion-exchange with different cations (Na+, NH4 +, Li+, Ba2+ and Fe3+) was performed in binderless 13X zeolite pellets. Original and cation-exchanged samples were characterized by thermogravimetric analysis coupled with mass spectrometry (inert atmosphere), X-ray powder diffraction and N2 adsorption/desorption isotherms at 77 K. Despite the presence of other cations than Na (as revealed in TG-MS), crystalline structure and textural properties were not significantly altered upon ion-exchange. Single component equilibrium adsorption isotherms of carbon dioxide (CO2) and methane (CH4) were measured for all samples up to 10 bar at 298 and 348 K using a magnetic suspension balance. All of these isotherms are type Ia and maximum adsorption capacities decrease in the order Li > Na > NH4–Ba > Fe for CO2 and NH4–Na > Li > Ba for CH4. In addition to that, equilibrium adsorption data were measured for CO2/CH4 mixtures for representative compositions of biogas (50 % each gas, in vol.) and natural gas (30 %/70 %, in vol.) in order to assess CO2 selectivity in such scenarios. The application of the Extended Sips Model for samples BaX and NaX led to an overall better agreement with experimental data of binary gas adsorption as compared to the Extended Langmuir Model. Fresh sample LiX show promise to be a better adsorption than NaX for pressure swing separation (CO2/CH4), due to its higher working capacity, selectivity and lower adsorption enthalpy. Nevertheless, cation stability for both this samples and NH4X should be further investigated.  相似文献   

11.
The hydrogen-bonded structures of the CH3OH complexes with CF4, C2F2, OC, Ne, and He are designated as the starting points for geometry optimizations without and with counterpoise (CP) correction at MP2 level of theory with the basis sets 6-31+G*, 6-31++G**, and 6-311++G**, respectively. Tight convergence criteria are applied throughout all geometry optimizations in order to reduce the computational errors. According to the optimizations without CP correction, a blue-shifted O–H···Y (where Y = F, O, Ne, or He) hydrogen bond exists in all these five complexes. The magnitudes of blue shifts of ν(O–H) of the former four complexes with respect to that of CH3OH are reduced greatly when the polarization and diffuse functions of the hydrogen atoms are added (results from 6-31+G* versus those from 6-31++G**). However, for the complexes CH3OH–CF4 and CH3OH–C2F2, our optimizations using the CP corrections did not find the hydrogen-bonded structure to be a stationary point. The energy minimum of both the complexes corresponds to a non-hydrogen-bonded structure.  相似文献   

12.
The new alkoxysilyl-functionalized alkynes [HC≡CCH2N(H)C(=O)N(H)(CH2)3Si(OEt)3] and [HC≡C(C6H4)–N(H)C(=O)N(H)(CH2)3Si(OEt)3] have been synthesized using literature methods. These have been reacted with Fe3(CO)12, Ru3(CO)12 and Co2(CO)8. With the iron carbonyl only decomposition was observed: with Ru3(CO)12 splitting of the alkynes into their parent components and formation of the complexes (μ-H)Ru3(CO)9[HC=N(CH2)3Si(OEt)3], (μ-H)Ru3(CO)9[C–C(C6H4)NH2] and (μ-H)2Ru3(CO)9[HC–CCH3] occurred. Finally, with Co2(CO)8 formation of complexes Co2(CO)6(HC2R) R=(C6H4)NH2, CH2NH(CO)NH(CH2)3Si(OEt)3, (C6H4)NH(CO)NH(CH2)3Si(OEt)3 containing the intact alkynes could be obtained.  相似文献   

13.
The electrochemical reduction of CO2 with a Cu electrode in methanol was investigated with sodium hydroxide supporting salt. A divided H-type cell was employed; the supporting electrolytes were 80 mmol dm−3 sodium hydroxide in methanol (catholyte) and 300 mmol dm−3 potassium hydroxide in methanol (anolyte). The main products from CO2 were methane, ethylene, carbon monoxide, and formic acid. The maximum current efficiency for hydrocarbons (methane and ethylene) was 80.6%, at −4.0 V vs Ag/AgCl, saturated KCl. The ratio of current efficiency for methane/ethylene, r f(CH4)/r f(C2H4), was similar to those obtained in LiOH/methanol-based electrolyte and larger relative to those in methanol using KOH, RbOH, and CsOH supporting salts. In NaOH/methanol-based electrolyte, the efficiency of hydrogen formation, a competing reaction of CO2 reduction, was suppressed to below 4%. The electrochemical CO2 reduction to methane may be able to proceed efficiently in a hydrophilic environment near the electrode surface provided by sodium cation.  相似文献   

14.
Direct on-line studies of a C2HCl3/He/O2 microwave discharge plasma made possible the evolution and detection of many unfamiliar ionic species. Numerous ionic chlorocarbons, chlorohydrocarbons, oxygenated chlorohydrocarbons, oxygenated hydrocarbon radicals, and simple hydrocarbon species were identified mass spectrometrically as by-products: C m Cl n (m = 1–4, 6, 8; n = 1–8), C m H n Cl x (m = 1–4, 6, 7, 10; n, x = 1–6), C m H n Cl x O y (m = 1–5, 12; n = 1–7; x = 1, 2, 4, 6; y = 1–3), C n H2n−1O (n = 2, 3), C m H n (m = 2, 4, 6, 8; n = 2, 4), and so on. The studies clearly showed the presence of various unfamiliar positive ionic O-containing species such as C2ClO2, CCl3CO, C2H2Cl4O2, and C4H2Cl6O3. It is apparent that positive-ion reactions play a significant role in producing many ionic species in the chemistry of C2HCl3 plasmas.  相似文献   

15.
The cation [CpRu(η6-C10H8)]+ was shown to exchange naphthalene for other arenes under visible-light irradiation to form the complexes [CpRu (η6-arene)]+ (arene = C6H6, 1,4-C6H4Me2, 1,3,5-C6H3Me3, or 1,2,4,5-C 6H2Me4) in 70–95% yields. The reaction rate of exchange decreases in the series arene = 1,4-C6H4Me2 > C6H6 > 1,3,5-C6H3Me3 > 1,2,4,5-C 6H2Me4 >> C6Me6 and increases with the coordinating ability of the solvent in the order CH2Cl2 < THF—CH2Cl2 mixture (1: 1) < acetone.  相似文献   

16.
During recent developments on the theories and experimental techniques of compressed liquids and liquid mixtures, it has been revealed that there exist some regularities. Among these, the regularity found by Huang and O'Connell is that the isotherms of reduced bulk modulus of compressed liquids as a function of molar volume intersect at a common point. This intersection is a useful tool for evaluating the reliability of an equation of state (EOS) for producing equilibrium properties of matter. This paper also deals with an extension of the above regularity to some liquefied natural gas (LNG) mixtures including: N2+CH4, N2+C2H6, CH4+C2H6, CH4+C3H8, and CH4+C4H10 at different temperatures. The present work gives a theoretical analysis for the common bulk modulus point in terms of a statistical‐mechanical equation of state for mixtures. In addition, we have calculated excess molar volume of N2+CH4 mixture in terms of temperature and compared it with experimental values.  相似文献   

17.
The ortho-metalated complex [Pd(x){κ 2 (C,N)-[C6H4CH2NRR′ (Y)}] (2a4a and 2b3b) was prepared by refluxing in benzene equimolecular amounts of Pd(OAc)2 and secondary benzylamine [a, EtNHCH2Ph; b, t-BuNHCH2Ph followed by addition of excess NaCl. The reaction of the complexes [Pd(x){κ 2 (C,N)-[C6H4CH2NRR′ (Y)}] (2a4a and 2b3b) with a stoichiometric amount of Ph3P=C(H)COC6H4-4-Z (Z = Br, Ph) (ZBPPY) (1:1 molar ratio), in THF at low temperature, gives the cationic derivatives [Pd(OC(Z-4-C6H4C=CHPPh3){κ 2 (C,N)-[C6H4CH2NRR′(Y)}] (5a9a, 4b6b, and 4b′6b′), in which the ylide ligand is O-coordinated to the Pd(II) center and trans to the ortho-metalated C(6)H(4) group, in an “end-on carbonyl”. Ortho-metallation, ylide O-coordination, and C-coordination in complexes (5a9a, 4b6b, and 4b′6b′) were characterized by elemental analysis as well as various spectroscopic techniques.  相似文献   

18.
Photolysis of a solution of Cp*RuCp (1) in CF3CO2H generates salt [CpRu(C5Me4CH2)]-(O2CCF3)(2 • O2CCF3). The reaction of compound 1 with oleum at 20 °C through the intermediate dication [η5-(CH2C5Me4)Ru(μ:η55-C5H4C5H5)Ru(C5Me4CH2)-η6]2+ leads to the triply charged cation η7CH2)2C5Me3Ru(μη55-C5H4C5H4)Ru(C5Me4CH2)-η6]3+. Synthesis of pentamethylmetallocene derivatives CpMC5Me4X (M = Ru, Fe; X = CHO, CH2OH, CH2An) has been accomplished. The reactions of 1-hydroxymethyl-2,3,4,5-tetramethylruthenocene with acids CF3CO2H, HBF4, CF3CO2H/NaB[C6H3(CF3)2]4, and picric acid C6H2(NO2)3OH afforded salts 2•X (X = CF3CO2, BF4, B[C6H3(CF3)2]4), and (2,3,4,5-tetram ethylruthenocenyl)methyl picrate [CpRu(C5Me4CH2)-η6][(C6H2(NO2)3O] (2•C6H2(NO2)3O). Structure of the latter was characterized by single crystal X-ray diffraction.  相似文献   

19.
Methane-intercalated fullerite (CH4)0.56C60 was obtained by low-temperature precipitation from solution. Methane transition from the gas phase to the octahedral void of fullerite is accompanied by a bathochromic shift of normal vibrational frequencies (by 19 and 8 cm−1 for ν3 and ν4, respectively). The methane 13C signal in the proton decoupling 13C NMR spectrum is observed as a singlet at δ−0.42. According to quantum chemical calculations using density functional theory, location of methane in the octahedral void of fullerite (C60)6 leads to a decrease in the total energy of fullerite by 4 kcal mol−1.  相似文献   

20.
Abstract  Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H2O)(NBD)][BF4] (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C9H96-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2. The reaction of [Cp*Ru(H2O)(NBD)][BF4] with 1,4-diphenylbutadiyne generates the unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C9H8–Ph in addition to the organometallic compound [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4]. [C9H96-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BPh4]2 is generated after the reaction of compound [C9H96-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2 with Na[BPh4]. The structure of this compound was confirmed by X-ray diffraction. A possible approach to form Ph–C≡C–C9H8–Ph and [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4] is suggested. Graphical Abstract  Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H2O)(NBD)]BF4 (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C9H96-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2. The reaction of [Cp*Ru(H2O)(NBD)][BF4] with 1,4-diphenylbutadiyne simply generates unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C9H8–Ph in addition to the organometallic compound [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4]. [C9H96-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BPh4]2 is generated after the reaction of compound [C9H96-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2 with Na[BPh4]. The structure of this compound was confirmed by X-ray diffraction. And the possible approach to form Ph–C≡C–C9H8–Ph and [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4] was suggested. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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