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Grand Canonical Monte Carlo (GCMC) simulation and Molecular Dynamics (MD) simulations were used to study the effects of temperature (310 K to 400 K), pressure (≤30 MPa) and water content (0 molecule/nm3 to 9 molecule/nm3) on the adsorption and diffusion behavior of CH4 and C2H6 in 3 nm kaolinite slit under supercritical conditions. The obtained adsorption capacity, isosteric adsorption heat, concentration distribution and diffusion coefficient were analyzed and compared. The simulation results show that the adsorption capacity of C2H6 is higher under low pressure conditions, and the adsorption capacity of CH4 is higher under high pressure conditions due to the small molecular radius and increased adsorption space. The addition of water molecules and the increase in temperature will reduce the adsorption capacity and isosteric adsorption heat of the two gases. We analyzed the changes in Langmuir volume and Langmuir pressure of the two gases under different temperature and water content conditions. The addition of water molecules and the increase in temperature will reduce the saturation adsorption capacity (which has a greater effect on C2H6) and the adsorption rate of the two gases in the kaolinite slit. The water molecules occupy the adsorption site of the gas molecules (limiting the diffusion of the gas molecules), which reduces the interaction between gas molecules and the wall surface, thus altering the distribution of the two gases in the slit. The increase in temperature will accelerate the oscillation of the gas molecules, increasing diffusion, and also leads to a reduction in the peak value of the adsorption peaks of the two gases.

Gas hydrates form at various facilities related to the natural gas and process equipment in oil and gas fields, refineries, petrochemical and facilities in the chemical industry, in the presence of both natural gas and water, at high pressure and low temperature. In the present study, the equilibrium conditions of gas hydrate mixture formation including methane and ethane and also pure ethane are investigated. The conditions for binary hydrate formation without the presence of inhibitors have been used and the empirical research available in the field has been used to evaluate the accuracy of the present modeling. Hydoff software was used for modeling and the hydrate formation pressure was calculated. In order to evaluate the accuracy of the modeling, the values related to the calculation error were calculated from the existing experimental research and the results showed that there are 11%, 14% and 0.08% errors with Deaton & Frost, McLeod & Campbell, Holder & Grigoriou research, respectively. Therefore, it can be concluded that the best case for modeling according to the experimental results is Holder & Grigoriou, and therefore a mathematical model is presented to estimate the formation conditions of the binary mixture of methane and ethane, which can be used with very high accuracy. Pure ethane was also tested with potassium chloride, sodium chloride and 5% methanol inhibitors and also without inhibitors and the results showed that the effect of adding methanol is greater than sodium chloride and potassium chloride, respectively, and ethane hydrate is formed at higher pressures.

Research in ultra-low temperature refrigeration applications has intensified in recent years after the appearance of vaccines in response to the COVID-19 pandemic. There are few current technologies for this low-temperature range, with reduced energy performance and high global warming potential refrigerants. This work analyses the introduction of the ejector in two-stage cascade cycles for ultra-low temperature refrigeration. The proposal includes the assessment of the behaviour of the ejector while implementing it in a single stage or simultaneously in both stages. The study is carried out with refrigerants R-290 in the high-temperature stage and R-170 in the low-temperature stage since these are natural refrigerants with very low global warming potential. The results show that the ejector is a component that causes improvements in the cycle when placed in the high-temperature and low-temperature stages. On the other hand, changing evaporation and condensation temperatures, the evaporation temperature is more critical regarding cycle energy performance. With the results obtained, a cascade cycle with an ejector in both stages is proposed, obtaining a 21% higher coefficient of performance than the standard cascade cycle. Also, the cycle with the ejector in both stages causes an improvement of 13.6% compared to the previous generation's refrigerants (R-23 and R-507A) in the same cycle. The carbon footprint analysis shows that this cycle emits less than half of the equivalent CO2 than actual cycles for ultra-low temperatures, also with a new refrigerant like R-472A.

A gas sensor based on light-induced thermo-elastic spectroscopy (LITES) capable to detect methane (C1) and ethane (C2) in a wide concentration range, from percent down to part-per-billion (ppb), is here reported. A novel approach has been implemented, exploiting a compact sensor design that accommodates both a custom 9.8 kHz quartz tuning fork (QTF) used as photodetector and the gas sample in the same housing. The resulting optical pathlength was only 2.5 cm. An interband cascade laser (ICL) with emission wavelength of 3.345 µm was used to target absorption features of C1 and C2. The effects of high concentration analytes on sensor response were firstly investigated. C1 concentration varied from 1% to 10%, while C2 concentration varied from 0.1% to 1%. These ranges were selected to retrace the typical natural gas composition in a 1:10 nitrogen dilution. The LITES sensor was calibrated for both the gas species independently and returned nonlinear but monotonic responses for the two analytes. These univariate calibrations were used to retrieve the composition of C1-C2 binary mixtures with accuracy higher than 98%, without the need for further data analysis. Minimum detection limits of ∼650 ppb and ∼90 ppb were achieved at 10 s of integration time for C1 and C2, respectively, demonstrating the capability of the developed LITES sensor to operate with concentration ranges spanning over 6 orders of magnitude.

Abstract The oil and gas (O&G) sector is estimated to be the largest contributor to anthropogenic methane (CH4) emissions in Colorado. Since 2004, the State of Colorado has implemented multiple regulations to significantly reduce emissions from the O&G sector. The Denver‐Julesburg Basin (DJ Basin) is a significant O&G producing region in northern Colorado, and O&G production here has steadily increased over the last decade. To assess CH4 trends in Northern Colorado, we selected CH4 retrievals from the NASA Atmospheric Infrared Sounder (AIRS) instrument for 2003–2020. The study grid cell includes Denver, Boulder, and much of the dense O&G production in the DJ Basin. We computed mean June‐August ascending node AIRS 700 hPa CH4 for each year and subtracted mean June–August CH4 sampled at NOAA's Niwot Ridge (NWR) station, a high‐altitude background site. Differences represent estimated enhancement over background. Linear regression shows an annual change of −2.84 ppb ± 0.8 ppb from 2012 to 2020 (R2 0.90) and an estimated reduction of 56% for 2012–2020, despite substantial increases in O&G production. Local CH4 enhancement is strongly correlated with surface measurements of ethane at Platteville which is in the center of the O&G fields (correlation coefficient 0.96), and this is evidence that reductions in O&G emissions are driving reductions in CH4. We conclude that AIRS CH4 can be used to measure the efficacy of emissions control programs in this region and that regulatory requirements are having an effect.

To break through the thermodynamic reaction limitation of ethane dehydrogenation to ethylene, the oxidative dehydrogenation in the presence of O2 and chemical looping oxidative dehydrogenation has been investigated with the oxygen storage oxide compound. LaMnO3 perovskite catalysts with large specific surface areas were prepared using citric acid-nitrate combustion. The oxygen vacancies and M4+ contents in the catalysts were improved by doping LaMnO3 as the active sites. The experimental results show that the catalyst not only promotes ethane dehydrogenation through selective hydrogen combustion but also promotes ethane conversion through activation of CH. The catalyst exhibits good stability in oxidative dehydrogenation reaction.

Adsorbed natural gas (ANG) is a promising solution for improving the safety and storage capacity of low-pressure gas storage systems. The structural–energetic and adsorption properties of active carbon ACPK, synthesized from cheap peat raw materials, are presented. Calculations of the methane–ethane mixture adsorption on ACPK were performed using the experimental adsorption isotherms of pure components. It is shown that the accumulation of ethane can significantly increase the energy capacity of the ANG storage. Numerical molecular modeling of the methane–ethane mixture adsorption in slit-like model micropores has been carried out. The molecular effects associated with the displacement of ethane by methane molecules and the formation of a molecule layered structure are shown. The integral molecular adsorption isotherm of the mixture according to the molecular modeling adequately corresponds to the ideal adsorbed solution theory (IAST). The cyclic processes of gas charging and discharging from the ANG storage based on the ACPK are simulated in three modes: adiabatic, isothermal, and thermocontrolled. The adiabatic mode leads to a loss of 27–33% of energy capacity at 3.5 MPa compared to the isothermal mode, which has a 9.4–19.5% lower energy capacity compared to the thermocontrolled mode, with more efficient desorption of both methane and ethane. [ABSTRACT FROM AUTHOR]

The study here presents data from the literature regarding the characteristic parameters of explosion propagation in gaseous ethane–air mixtures. The maximum explosion pressures, maximum explosion times, maximum rates of pressure increase, and deflagration indices from experimental measurements are discussed and analyzed against the initial pressure, initial temperature, and equivalence ratio, as well as the explosion vessel characteristics. Ethane is used for ethylene production, as a refrigerant in cryogenic systems, as an alternative clean fuel in the power generation industry and automotive propulsion, and for many other applications. Therefore, the explosion characteristics of its mixtures with air are of great interest for explosions occurring after accidentally forming flammable mixtures, as well as for the prediction of combustors' performances and/or engines that work in different conditions. [ABSTRACT FROM AUTHOR]

Geochemical studies of gases from low-permeability reservoirs have raised new questions regarding the chemical and stable isotope systematics of gas hydrocarbons. For instance, the possibility of thermodynamic equilibrium is recurrently in discussion. However, it is not clear whether there is anything "unconventional" in the way these systems continue to be studied. Using molecular and stable carbon isotope data from North American unconventional and conventional reservoirs, this research has applied two parameters that well describe key transformation stages during gas generation. The δ13C of ethane and the C2/C3 ratio increase from baseline values (<1%Ro, prominent kerogen cracking) until a first inflexion at 1.5%Ro. The same inflexion leads to 13C depletion of ethane and a rapidly increasing C2/C3 ratio as hydrocarbon cracking becomes prominent. The transition between these two stages is proposed to be a crossover from equilibrium to non-equilibrium conditions. There is no evidence for these characteristics to be limited to low-permeability reservoirs. Unconventional gas geochemistry should represent an approach that acknowledges that chemical and isotope distributions are not ruled by only one mechanism but several and at specific intervals of the thermal history. [ABSTRACT FROM AUTHOR]

Objective The co-cracking technology of ethane and propane is optimized. Methods The BSPA ethylene cracking evaluation test equipment of KBR company is used to optimize the separate cracking of ethane and propane and the blending cracking technology according to different ratios in the laboratory. Results When the blend proportion of ethane is 20 %- 90 %, t he yields of ethylene, diene and triene are increased. When the blend proportion of ethane is 80%-90%, the highest yields of ethylene, diene and triene are 55. 28 %, 56. 05 % and 58. 01 %, respectively. Conclusion T he optimized result is applied in industrial ethylene cracking plant, the total ethylene yield and the diene yield don't decrease when the proportion of light cracking feedst0ck in t he whole cracking feedstock reduced more than 10%, and the remarkable industrial application effect has been obtained. [ABSTRACT FROM AUTHOR]

Co/Al2O3 catalysts with different Co loadings and different calcination temperatures exhibit totally various catalytic performances for ethane dehydrogenation. At lower loadings, isolated Co2+ species in the framework of CoAl2O4 formed via strong interaction between Co and alumina leads to selective activation of C–H bond and the resulting high selectivity to ethylene. While a higher Co loading with the formation of aggregated metallic Co species through the in-situ reduction of Co3O4 on the catalyst surface results in C–C bond cracking to methane. Moreover, given the results of structural characterization and activity test, the increased calcination temperature enhances the interaction between Co species and alumina and facilitates the formation of CoAl2O4 even at a relatively high Co loading of 5%, contributing to the significant improvement of the catalytic behavior from undesired C–C bond breakage to C–H bond rupture. [ABSTRACT FROM AUTHOR]

Source attribution of natural gas emissions from fossil fuels in New Mexico's San Juan Basin (SJB) is challenging due to source heterogeneity and emissions transience. We demonstrate that ethane (C2H6) to methane (CH4) mixing ratios can identify and separate sources over different scales using various measurement techniques. We report simultaneous CH4 and C2H6 observations near a coal mine vent and oil and gas (O&G) emission sources using ground‐based in situ measurements in 2020/2021. During these campaigns, we observed a stable coal vent C2H6:CH4 ratio of 1.28% ± 0.11%, discernibly different than nearby O&G source ratios ranging from 0.9% to 16.8%. We analyze airborne observations of the SJB taken in 2014/2015 that exhibit similar coal vent ratios and further show the region's heterogeneity. We identify episodic O&G sources, including a gas plant source detected in 2014/2015 that is absent in our 2020/2021 data. We examine total column observations of C2H6 and CH4 made in 2013 with a solar spectrometer and find a C2H6:CH4 ratio of 1.3% ± 0.4% for the coal vent. The stable and unique coal vent ratio relative to other O&G sources in the region is used to demonstrate that consistent attribution is possible using various measurement methods at multiple scales across many years. Finally, we demonstrate that using C2H6 as a proxy for fossil CH4 inversions can inform detailed basin‐scale inversions, provided we understand source specific changes in the C2H6:CH4 ratio like we report in the SJB. Plain Language Summary: Oil, gas, and coal production processes are known to emit methane, a potent greenhouse gas, and other hydrocarbon air pollutants. Attributing these emissions to specific anthropogenic fossil sources is challenging in the vast and variable infrastructure. Ethane is often co‐emitted with methane and the ratio of ethane to methane in emission sources varies significantly with source types. By measuring this ratio with high sensitivity and accuracy, we can "fingerprint" gas sources by their unique ratio. We report simultaneous measurements of ethane and methane, and an empirical analysis of the ratio to demonstrate source specific attribution. Our varied measurement techniques spanning spatial scales (near‐source ground, airborne, and remote sensing) were used to sample sources in New Mexico's San Juan basin over 8 years. Despite a diverse and changing emissions environment, ethane to methane ratios were successfully used to identify and apportion several sources across scales in space and time. Specifically, our measurements show consistent and stable ethane to methane ratios from a large coal vent source in the study region. Our findings inform efforts seeking to characterize and quantify gas emissions in fossil extraction regions using multi‐scale data from diverse instruments. Key Points: Multiple measurement techniques across spatiotemporal scales show consistent and stable ethane:methane ratios from a coal vent shaftEthane:methane ratios are a valuable tool for source apportionment, plume separation, and oil and gas basin emissions characterizationA large gas plant source was identified in 2015 but abated in 2021 showing change with time and monitoring [ABSTRACT FROM AUTHOR]

[Display omitted] • ODH of ethane by CO 2 is an energy-efficient way of utilizing shale gas. • The reversion between Ce3+ and Ce4+ keeping the catalyst active and stable. • CsRu/CeO 2 has higher selectivity of light olefins than Ru/CeO 2. Oxidative and non-oxidative ethane dehydrogenation were studied and compared over Cs-promoted Ru/CeO 2 catalyst. The presence of CO 2 improved the ethane conversion to ethylene and led to the formation of C 3 and C 4 olefins as well. The olefin selectivity and yield in ODH were affected by reaction variables including CO 2 /C 2 H 6 ratio, temperature, and feed rate. The CsRu/CeO 2 remained stable activity for 93 days under reactive conditions wherein intermittent shutdowns and startups were performed. Mechanistically, the interaction between Cs and Ru with ceria in the crystalline structure facilitated reduction and oxidation cycles. It was postulated that Ce3+ had a strong tendency to react with CO 2 to form Ce4+, whereas Ce4+ was reduced by hydrogen from ethane dehydrogenation to form Ce3+. The redox cycle can be repeated during the ODH reaction keeping the catalyst active. Furthermore, in the ODH reaction, the CsRu/CeO 2 catalyst exhibited resistance to carbon deposition, evidenced by the carbon balance measurement. [ABSTRACT FROM AUTHOR]

In this work, a series of cobalt doped hexagonal mesoporous silica (Co‐HMS) with the different Co content were prepared by direct hydrothermal method and applied to oxidative dehydrogenation (ODH) reaction of ethane with carbon dioxide. Structural and chemical properties of the catalysts were characterized by nitrogen adsorption, X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), electron dispersive spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), and Raman and ultraviolet–visible (UV‐vis) spectroscopy. These characterizations showed that cobalt not only entered the framework of Co‐HMS catalysts but also was evenly dispersed in the bulk. The valence state and coordination mode of cobalt played an important role in the whole ODH reaction system of ethane with carbon dioxide. 2% Co‐HMS with dominant Co2+ had the highest conversion of ethane (26.0%). With the different cobalt content in the catalyst, the proportion of Co2+(Td) and Co2+(Oh) is also different. 1% Co‐HMS with more Co2+(Td) performed the highest ethylene selectivity of 86.7%, which was stable during the 10 h reaction time. [ABSTRACT FROM AUTHOR]

To achieve high selectivity in photocatalytic CO 2 reduction to C 2+ products, increasing the number of CO 2 adsorption sites and lowering the energy barriers for key intermediates are critical. A ZnIn 2 S 4 (ZIS)/MoO 3-x (Z-M) photocatalyst is presented, in which plasmonic MoO 3-x generates hot electrons, creating a multielectron environment in ZIS that facilitates efficient C─C coupling reactions. Density functional theory (DFT) calculations reveal that MoO 3-x reduces the formation energy of sulfur vacancies (S V ) in ZIS, thereby enhancing CO 2 adsorption and activation. The S V -rich surface lowers the energy barrier for forming HCOO * to -0.33 eV whereas the energy barrier for forming * COOH is 0.77 eV. Successive hydrogenation of HCOO * leads to * CH 2 , which converts to * CH 3 with an energy barrier of -0.63 eV. The energy barrier for * CH 3 -CH 3 coupling is 0.54 eV, which is lower than the 0.73 eV for * CH 2 -CH 2 coupling to form * C 2 H 4 . Thus, Z-M preferentially produces C 2 H 6 over C 2 H 4 . Under visible light, Z-M achieves a CO 2 -to-C 2 H 6 conversion rate of 467.3 µmol g -1 h -1 with 92.0% selectivity. This work highlights the dual role of plasmonic photocatalysts in enhancing CO 2 adsorption and improving C 2+ production in CO 2 reduction., (© 2024 Wiley‐VCH GmbH.)

Oil and natural gas (O&G) production and processing activities have changed markedly across the U.S. over the past several years. However, the impacts of these changes on air pollution and greenhouse gas emissions are not clear. In this study, we examine U.S. ethane (C 2 H 6 ) emissions, which are primarily from O&G activities, during years 2015-2020. We use C 2 H 6 observations made by the NOAA Global Monitoring Laboratory and partner organizations from towers and aircraft and estimate emissions from these observations by using an inverse model. We find that U.S. C 2 H 6 emissions (4.43 ± 0.2 Tg·yr -1 ) are approximately three times those estimated by the EPA's 2017 National Emissions Inventory (NEI) platform (1.54 Tg·yr -1 ) and exhibit a very different seasonal cycle. We also find that changes in U.S. C 2 H 6 emissions are decoupled from reported changes in production; emissions increased 6.3 ± 7.6% (0.25 ± 0.31 Tg) between 2015 and 2020 while reported C 2 H 6 production increased by a much larger amount (78%). Our results also suggest an apparent correlation between C 2 H 6 emissions and C 2 H 6 spot prices, where prices could be a proxy for pressure on the infrastructure across the supply chain. Overall, these results provide insight into how U.S. C 2 H 6 emissions are changing over time.

Redox conversion of ethane at 600 °C on Mo-containing oxide systems differing in the composition and preparation method was studied. The ethane conversion and the selectivity of the ethylene formation increase in the series of MoO3 samples supported on SiO2 (silica gel), TiO2 (anatase), and alumina. The efficiency of the MoO3/Al2O3 systems increased when HNO3 was added to a (NH4)6Mo7O24 solution used to impregnate the support, and also when γ-Al2O3 was replaced with Al(OH)3. Gallium oxide additives improve the properties of the MoO3/Al2O3 system, increasing the ethane conversion to 44% at ethylene formation selectivity of more than 96%. The systems under consideration are characterized by high stability and retain their activity after five reaction—regeneration cycles. Based on the data obtained during the reaction of ethane with the Mo systems and in the course of regeneration of the reduced samples with oxygen, the content of active oxygen corresponding to the MoO3 ↔ MoO2 transformation was assessed. [ABSTRACT FROM AUTHOR]

The potential of on‐purpose ethylene production, in parallel with CO2 conversion to CO, is of great interest. Iron oxide‐based catalysts supported on mixed oxides zNiO−MgO−ZrO2, z=0–10 wt%, are active for the CO2‐assisted oxidative dehydrogenation of ethane at 873 K and 101.3 kPa. Enhanced control of their selectivity towards C−H bond cleavage and not towards C−C bond cleavage can be achieved by adjusting the Ni/Fe ratio. Fine tuning Ni/Fe molar ratio results in stable catalytic performance, with selectivity towards C2H4 >65 % and C2H6 conversion >20 %. Density functional theory (DFT) calculations show a significant enhancement in activity due to decrease in the oxygen‐vacancy formation energy and the increase in hydrogen adsorption energy at the Ni oxide‐Fe oxide interface. The latter interface is the potential active site responsible for the enhanced performance that was experimentally exemplified for the Fe oxide/zNiO−MgO−ZrO2 catalysts vs Fe oxide/MgO−ZrO2. [ABSTRACT FROM AUTHOR]

Copyright of Safety & Fire Technology (2657-8808) is the property of Centrum Naukowo-Badawcze Ochrony Przeciwpozarowej and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We proposed a six-gas simultaneous detection system for methane (CH4), ethane (C2H6), acetylene (C2H2), ethylene (C2H4), carbon monoxide (CO) and carbon dioxide (CO2) based on wavelength modulation spectroscopy (WMS). Five different near infrared distributed feedback (DFB) lasers combined with a custom $5\times1$ wavelength division multiplexer were used to detect the six gases. The lasers were modulated at five different sinusoidal signals and the detection light intensity signals were demodulated with corresponding sinusoidal signals, which can be named frequency division multiplexing (FDM). Among them, CH4 and C2H6 were measured with one laser based on time division multiplexing (TDM). The principle of four multi-gas detection based on FDM was also derived. To miniaturize the device, a Raspberry Pi was used for data processing based on python, and the detected gas concentrations can be displayed directly on the screen. The six-gas sensing system exhibits detection limits of 247 ppb, 1.28 ppm, 126 ppb, 982 ppb, 2.55 ppm and 4.87 ppm with average time of 1 s for CH4, C2H6, C2H2, C2H4, CO and CO2, respectively. With an average time extended to 100 s, the measurement precision achieves 24 ppb, 135 ppb, 14 ppb, 141 ppb, 495 ppb and 608 ppb, respectively. With a fast response time, compact size and high detection sensitivity, the detection system is promising for dissolved gas analysis (DGA) in transformer oil and other material aging process. [ABSTRACT FROM AUTHOR]

[Display omitted] The photocatalytic reduction of carbon dioxide (CO 2) to fossil fuels has attracted widespread attention. However, obtaining the high value-added hydrocarbons, especially C 2+ products, remains a considerable challenge. Herein, gold (Au) nanoparticle-modified bismuth-rich bismuth oxybromide Bi 12 O 17 Br 2 nanotube composites were designed and tested. Au nanoparticles act as electron traps and thermal electron donors that promote the efficient separation and migration of carriers to form the C 2+ product. As a result, compared with the pure Bi 12 O 17 Br 2 nanotubes, Au@Bi 12 O 17 Br 2 composites can not only produce the carbon monoxide (CO) and methane (CH 4), but also covert CO 2 into ethane (C 2 H 6). In this study, Au@Bi 12 O 17 Br 2 -700 was used to obtain a C 2 H 6 production rate of 29.26 μmol h−1 g−1. The selectivities during a 5-hour test reached 94.86% for hydrocarbons and 90.81% for C 2 H 6. The proposed approach could be used to design high-performance photocatalysts to convert CO 2 into high value-added hydrocarbon products. [ABSTRACT FROM AUTHOR]

Summary: Ethane recovery is an important way to increase the economic benefits of unconventional natural gas, such as shale gas. However, current researches did not focus on obtaining high purity and high recovery rate of ethane. In this study, two pure refrigerant cascade natural gas liquefaction processes without (Process 1) or with (Process 2) flash gas recovery are proposed to coproduce high‐purity liquefied ethane gas (LEG) and liquefied natural gas (LNG). The proposed processes are combined with advanced distillation methods to reduce the energy consumption through process and energy integration. Aspen HYSYS V11 and genetic algorithm (GA) are used to simulate proposed processes and optimize the refrigeration cycles, respectively. To search the optimal conditions of distillation column, power consumption under different distillation pressure is comparatively analyzed, and the optimal distillation pressure is about 2.7 MPa. According to the optimization results, the specific power consumption of Process 1 is 0.4384 ~ 0.4584 kWh/Nm3(NG), and that of Process 2 is 0.4336 ~ 0.4503 kWh/Nm3(NG) when ethane content is 10% ~ 40%. Process 2 is preferred for lower power consumption and no material waste. Further study is conducted to research the effect of throttling temperature and ethane content on the system performance of Process 2. In addition, the feasibility exploration of cryogenic compression shows that re‐compression of natural gas after distillation is not energy saving for the proposed process. [ABSTRACT FROM AUTHOR]

The thermal pyrolysis of ethane and propane at a pressure of 1–3 atm was experimentally studied in a through-flow reactor. Kinetic modeling of the process under these conditions showed good agreement with experimental data in terms of both the conversion of alkanes and the yield of pyrolysis products, which allowed us to expand the modeling range of pressure. The results obtained show that the pressure change in the range of 1–15 atm has no noticeable effect on the pyrolysis of light alkanes. On this basis, we concluded that the previously established effect of pressure on the oxidative cracking of ethane was associated with its effect on the oxidative stages of the process. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heavy oil reserves in the world represent 5.5 trillion barrels, which are equivalent to five times the conventional crude oil reserves. Heavy oil reserves will be the main petroleum source for the world's future demand for energy. To enhance the recovery of heavy oil/bitumen, solvent‐based recovery seems to be one of the most promising alternatives to costly thermal methods. Phase behaviour studies of light gases in heavy oil are therefore very important when designing surface facilities and for enhanced oil recovery operations. In this study, we present solubility data for carbon dioxide and ethane in Lloydminster heavy oil. Measurements were carried out using a microbalance at 290.2, 298.2, and 313.2 K and at pressures varying from 200–2000 kPa. Experimental data were regressed with the Peng‐Robinson (PR) equation of state. We also report results of the fractionation of the heavy oil and its characterization in terms of SARA (saturates, aromatics, resins, and asphaltenes) fractions. Henry's law constants for gaseous solvents were also regressed and reported. As expected, ethane had a higher solubility than CO2 in the heavy oil at all temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface Cr6+ and oxygen species were enriched to form Cr 2 O 7 2−. • Niδ+ species catalyzed the reaction between CO 2 and carbon deposit. • Carbon cycle-assisted oxygen cycle improved stability of Cr-based catalysts. • The 1Ni1CrO x /ZrO 2 produced ethylene steadily over a prolonged period of 38 h. The CO 2 -assisted oxidative dehydrogenation of ethane (CO 2 -ODHE) is known as an ecologically beneficial process for ethylene generation and CO 2 utilization. However, the quick deactivation of traditional Cr-based catalysts remains a considerable challenge. Herein, we report that a 1Ni1CrO x /ZrO 2 catalyst could be high active and stable for the CO 2 -ODHE reaction; it showed CO 2 conversion of 15.4 % and kept stable for 38 h at 600 °C, while the productivity of ethylene approached 325 μmol·min−1·g cat −1. Kinetic evaluations found a low apparent activation energy of 87.2 kJ/mol on the 1Ni1CrO x /ZrO 2 catalyst. Surface Cr6+ and oxygen species were enriched to form Cr 2 O 7 2− with the introduction of NiO. In addition, NiO improved the surface alkalinity and the affinity for oxygen, promoting the strong adsorption and easy activation of CO 2. Importantly, Niδ+ species catalyzed the reaction between CO 2 and surface-deposited carbon by redox cycling (carbon cycle), promoting Mars-van Krevelen-type carbon elimination and Cr6+ regeneration. The carbon cycle-assisted oxygen cycle on the Ni-Cr oxide catalysts could obviously enhance the carbon resistance and stable ethylene production, demonstrating potential application of Cr-based catalysts for CO 2 -ODHE reaction. [ABSTRACT FROM AUTHOR]

Cobalt-exchanged ZSM-5 catalyzes the ammoxidation of ethane (2 C 2 H 6 + 3 O 2 + 2 NH 3 → 2 CH 3 CN + 6 H 2 O), yet the active form of cobalt, the role of the Brønsted acidic zeolite, and the reaction pathways remain elusive. Comparisons of rates and selectivities of reactions at distinctive cobalt sites (Co2+ at Al pair sites (CoZ 2), Co 3 O 4 , cobalt phyllosilicate, and cobalt aluminate) suggest sites that form from CoZ 2 provide the greatest rates and selectivities for CH 3 CN and C 2 H 4 formation. Significantly, we revealed a large fraction of CH 3 CN appears to form directly through a trimolecular reaction at cobalt ions without desorption of intermediates. In parallel, a more conventional sequential pathway dehydrogenates C 2 H 6 , aminates C 2 H 4 , and oxidatively dehydrogenates C 2 H 5 NH 2 to produce CH 3 CN. Combined rate measurements with temperature programmed reactions and in situ infrared spectra demonstrate that O 2 -derived intermediates at cobalt ions initiate both reaction sequences by abstracting H-atom from C 2 H 6. [Display omitted] • Standard synthesis creates different distributions of cobalt species within H-ZSM-5. • ZSM-5 with cobalt ions only at Al pair sites gives greatest rates and selectivities. • O 2 -derived intermediates abstract H-atoms from C 2 H 6 to initiate the reaction. • CH 3 CN forms by a trimolecular primary reaction among C 2 H 6 , NH 3 , and O 2 at cobalt. • A parallel pathway forms CH 3 CN by C 2 H 4 amination and dehydrogenation. [ABSTRACT FROM AUTHOR]

The vanadium (V)-nitrogenase of Azotobacter vinelandii catalyses the in vitro conversion of carbon monoxide (CO) to hydrocarbons. Here we show that an A. vinelandii strain expressing the V-nitrogenase is capable of in vivo reduction of CO to ethylene (C2H4), ethane (C2H6) and propane (C3H8). Moreover, we demonstrate that CO is not used as a carbon source for cell growth, being instead reduced to hydrocarbons in a secondary metabolic pathway. These findings suggest a possible role of the ancient nitrogenase as an evolutionary link between the carbon and nitrogen cycles on Earth and establish a solid foundation for biotechnological adaptation of a whole-cell approach to recycling carbon wastes into hydrocarbon products. Thus, this study has several repercussions for evolution-, environment- and energy-related areas.

Glycerin, a low-valued waste from biodiesel production, and dopamine were used as precursors for adsorbent materials. The study is centered on the preparation and application of microporous activated carbon as adsorbent materials in the separation of ethane/ethylene and of gases that are natural gas or landfill gas components (ethane/methane and carbon dioxide/methane). The activated carbons were produced by the following sequence reactions: facile carbonization of a glycerin/dopamine mixture and chemical activation. Dopamine allowed the introduction of nitrogenated groups that improved the selectivity of the separations. The activating agent was KOH, but its mass ratio was kept lower than one to improve the sustainability of the final materials. The solids were characterized by N2 adsorption/desorption isotherms, SEM, FTIR spectroscopy, elemental analysis, and point of zero charges (pHPZC). The order for adsorption of the different adsorbates (in mmolg−1) on the most well performing material—Gdop0.75—is methane (2.5) < carbon dioxide (5.0) < ethylene (8.6) < ethane (8.9).

Photocatalytic oxidative dehydrogenation of ethane to ethylene with a high selectivity is an attractive reaction. In this study, different types of heterojunctions between Pd/TiO 2 and a second metal oxide semiconductor were designed and synthesized to realize high activity conversion of C 2 H 6 to C 2 H 4. Pd/TiO 2 -AgO heterojunction was proved with best reaction performance. The addition of AgO facilitated the activation of reactant molecules. It enhanced directional transfer of electron-hole pairs and separation efficiency of photogenerated carriers. Pd/TiO 2 -5 % AgO heterojunction was proved with the best separation ability of photogenerated carriers and the largest number of surface hydroxyl groups. Detailed charge transfer path and reaction mechanism were proposed and discussed. [Display omitted] • Different heterojunctions were evaluated for photocatalytic ethane-to-ethylene. • Semiconductors with lower VB and CB are beneficial for ethylene formation. • Combined DFT and in situ-FTIR to Investigate the reaction mechanism. • Quantitatively assessed the influence of capture agents on different products. [ABSTRACT FROM AUTHOR]

Recent studies have discovered that laminar lifted flames (LLFs) can be stabilized within a triangular stabilization regime (TSR), defined by the parameters of normalized lift-off height and Reynolds number. The stabilization mechanism of an LLF could be explained by using an effective Schmidt number over an extended pressure range. In this study, the existence of LLFs of pure ethane was confirmed for the first time, and their characteristics were investigated. However, the corresponding TSR was significantly shrunk compared to propane and butane. The reasons were discussed in relation to the effective Schmidt number. The variation in effective Schmidt number depending on lift-off height and fuel type was theoretically predicted by considering the relative influence of the volume expansion on flow velocity and fuel concentration. Two additional stabilization modes near the turbulent transition were examined. One is the pathway from LLFs within the TSR to turbulent lifted flames at higher Reynolds numbers, and the criteria for this transition were explained. The other is an additional stabilization mode having much larger lift-off heights near the blowout conditions, and its stabilization mechanism was discussed. [ABSTRACT FROM AUTHOR]

Methane is the fundamental raw material of the C1 chemical industry, with abundant reserves. Its direct conversion into high-value-added chemicals has great scientific significance and broad commercial potential for the efficient use of methane resources. However, it is difficult to convert methane into more useful hydrocarbons and hydrogen, as the reaction usually requires external energy to overcome thermodynamic limitations. Non-oxidative coupling of methane to produce ethane and hydrogen is a promising supply technology. Catalysts which can be adapted to various energy sources are key to this technology. In recent years, considerable progress has been made in the design and application of these thermal and photocatalysts. This review outlines some typical catalysts, and reviews the progress in the understanding of reaction mechanisms. Finally, suggestions for the development of high-selectivity and high-stability catalysts for the future are presented.

• Bubble departure diameter of methane/ethane mixtures was experimentally studied • Twelve well-known correlations were compared with the experimental data • An improved model was developed considering mass transfer and Marangoni flow • The new model can predict well for experimental data with the deviation of 18.78% Methane and ethane are the main components of liquefied natural gas (LNG) and mixed-refrigerant liquefaction cycles. The pool boiling characteristics and bubble dynamic parameters of methane/ethane mixtures are important for the design and optimization of LNG systems. In this study, visual experiments were carried out to investigate the pool boiling of methane, ethane and their mixtures on a horizontal flat surface. Heat transfer characteristics and bubble departure diameters were acquired at 0.3 MPa for different concentrations of the mixtures. The bubble departure diameter increases with the increase in superheat temperature and dimensionless Jacob number for all concentrations of the mixture. The non-linear variation with concentrations of the bubble departure diameter can be observed due to the effects of mixtures. The bubble departure diameters for mixtures were predicted by twelve existing correlations, with Cole's correlation having the lowest mean absolute relative deviation (MARD) of 46.28%, with only 38.78% points within ±30% deviation. Therefore, a new model for mixtures was developed based on force equilibrium analysis in this study. Marangoni force is taken into account in the proposed model, as well as the effects of mass transfer on the bubble growth rate in mixtures. The MARD of the new model is 18.78%, which is better than all the twelve existing correlations. [ABSTRACT FROM AUTHOR]

Protonic ceramic ethane fuel cells fed by hydrocarbon fuels are demonstrated to be effective energy conversion devices. However, their practical application is impeded by a lack of anode materials combining excellent catalytic activity with good chemical stability and anti‐carbon deposition properties. In this work, in which Sr2Fe1.5Mo0.5O6‐δ (SFM) double perovskite oxide is used as the matrix framework, catalytic activity toward H2 and C2H6 oxidation is systematically investigated using Ba‐doping. It is found that the concentration of the oxygen vacancy is gradually improved with increased Ba content to significantly enhance catalytic activity toward H2 and C2H6 oxidation. From the series studied, Ba0.6Sr1.4Fe1.5Mo0.5O6‐δ exhibits the highest catalytic activity, while the power densities of the electrolyte‐supported Ba0.6SFM/BaCe0.7Zr0.1Y0.2O3‐δ (BCZY)/La0.58Sr0.4Co0.2Fe0.8O3‐δ (LSCF)‐Sm0.2Ce0.8O2‐δ (SDC) single cell reach 205 and 138 mW cm–2 at 750°C in H2 and C2H6, respectively. The ethane conversion rate of the experimental cell is shown to reach 38.4%, while simultaneously maintaining ethylene selectivity at 95%. Furthermore, the single cell exhibits no significant attenuation during stable operation for 20 h, as well as demonstrating excellent anti‐coking performance. The proposed results suggest that Ba0.6Sr1.4Fe1.5Mo0.5O6‐δ represents a promising anode material for efficient hydrocarbon‐related electrochemical conversion to realize the coproduction of ethylene and power in protonic ceramic ethane fuel cells. [ABSTRACT FROM AUTHOR]

A series of the layered double oxides supported molybdenum oxide catalysts were synthesized and evaluated in the oxidative dehydrogenation of ethane with CO2 (CO2-ODHE). The 22.3 wt% Mo/LDO catalyst delivered a 92.3%selectivity to ethylene and a 7.9% ethane conversion at relatively low temperatures. The molybdenum oxide catalysts were fully characterized by XRD, BET, SEM, TEM, UV–vis, Raman TG, and XPS. Isolated [MoO4]2− dominated on the surface of the fresh 12.5 wt% Mo/LDO catalyst. With the increase of the Mo content, the Mo species transformed from [MoO4]2− to [Mo7O24]6− and [Mo8O26]4− on the 22.3 wt% and 30.1 wt% Mo/LDO catalysts, respectively. The redox mechanism was proposed and three Mo species including [MoO4]2−, [Mo7O24]6−, and [Mo8O26]4− showed quite different functions in the CO2-ODHE reaction: [MoO4]2−, with tetrahedral structure, preferred the non-selective pathway; [Mo7O24]6−, with an octahedral construction, promoted the selective pathway; and the existence of [Mo8O26]4− reduced the ability to activate ethane. This work provides detailed insights to further understand the relationship between structure–activity and the role of surface Mo species as well as their aggregation state in CO2-ODHE. [ABSTRACT FROM AUTHOR]

The rapid deactivation caused by coke deposits is the major obstacle to the ethane aromatization of Zn-based catalysts. We have successfully synthesized a Zn-embedded inside HZSM-5 crystal catalyst (Zn@HZSM-5) by hydrothermal synthesis using preformed Zn/SiO2 as the only silicone source. Based on various characterization results, including in situ etching XPS, operando DRIFTS, as well as NMR, it is found that Zn(OH)+ and [Zn–O–Zn]2+ species are active sites for ethane aromatization for zinc-based catalysts, and their dynamic transformation significantly changes reaction performance of ethane dehydrogenation. For the Zn/HZSM-5 catalyst, the existence of a large number of [Zn–O–Zn]2+ species causes higher initial ethane conversion and higher selectivity of aromatics, resulting in a large amount of coke deposits. Moreover, [Zn–O–Zn]2+ species on the Zn/HZSM-5 catalyst fast transit to Zn(OH)+ species and subsequently form the sintered ZnO species, leading to rapid deactivation. For the Zn@HZSM-5 catalyst, the embedded structure contributes to forming more Zn(OH)+ species and delays the transformation of the Zn(OH)+ species to [Zn–O–Zn]2+ species, resulting in slowly increased selectivity of aromatics during the reaction. Therefore, the Zn@HZSM-5 catalyst realizes stable ethane conversion with dynamic selectivity. [ABSTRACT FROM AUTHOR]

The laminar burning velocity (SL) was measured at sub-atmospheric pressure (0.84 atm) and an environmental temperature of 295 ± 2 K for two high C2H6 content fuel mixtures, 75% CH4 – 25% C2H6 (mixture M1), and 50% CH4 – 50% C2H6 (mixture M2), as well as the pure constituent fuels. The equivalence ratios for the experiments ranged between 0.8 and 1.4. Numerical calculations predicting SL were performed using 3 detailed reaction mechanisms, finding GRI-Mech 3.0 to achieve the best agreement at the pressure conditions evaluated. The pre-exponential factor of reaction H + O2 = O + OH (R38) was modified in order to improve the numerical results at sub-atmospheric conditions. Kinetic analysis by means of the defined reaction factor ( F R , i ± j ) was carried out to identify the mechanism for SL changes at sub-atmospheric conditions. According to the experimental results, SL increased by 15.9% and 26.3% for mixtures M1 and M2, respectively, at 0.84 atm as compared to 1.0 atm. The reaction pathways elaborated employing FR indicate that the increase in SL at sub-atmospheric conditions is caused by increased CH3 radical production by reaction C2H5 + H = 2CH3 (R159), which increases the formation of H radical through reactions O + CH3 = H + CH2O (R10) and O + CH3 = H + H2 + CO (R284). The recombination reactions associated with the production of CH4 and C2H6 also contribute to SL increases at sub-atmospheric conditions. [ABSTRACT FROM AUTHOR]

Dual fueling is a successful model in the engine combustion area which perks up the performance and emission fronts. The combined effect of using biodiesel and gas dual fueling shall address the problem associated with emissions and depletion of fossil fuels. Fuel derived from Annona squamosa seeds is a creditable biofuel, which is resulted from waste seeds. This paper characterizes the gaseous exhaust emission and performance model of a dual-fueled, direct injection diesel engine fueled with ethane as gaseous fuel and Annona squamosa biodiesel as the base and liquid fuel. Ethane is supplied with air in the intake manifold at different flow rates (five lpm and ten lpm). Ethane supply at ten lpm lowered HC emissions by seven ppm, CO by 0.4% and smoke emission by 0.2 BSU for biodiesel. In addition, ethane supply to biodiesel lowered the BSFC by 13 kg/kW-h and enhanced the efficiency by 0.4%. Hence, dual-fueling ethane is an effective technique for improving the usage of biofuels in diesel engine applications. [ABSTRACT FROM AUTHOR]

In order to have an economic absorption process design with the lowest energy consumption, it is necessary to measure the solubility of the gas in the desired solvent and evaluate its non-ideality at different operating conditions. Thermodynamic modeling is also used to predict solubility so that it can be used with good confidence in a wide range of temperature and pressure. For this purpose, the solubility of pure ethane gas in N-methyl-2-pyrrolidone (NMP) solvent at different temperatures (278.1, 298.1, and 328.1 K) and different pressures up to 14 bars was investigated using a batch stirred experimental absorption pressure decaying setup. The kinetic and equilibrium data of the absorption including the solubility coefficient, heat of absorption, entropy, and Gibbs free energy changes were calculated at different temperatures. Then, the solubility was predicted after adjusting the binary interaction parameters using ϕ - ϕ and ϕ - γ approaches by implementing PR-EOS, Wilson and UNIQUAC activity coefficient models. The absolute mean deviations produced by the models were less than 18.5% for PR-PR, less than 12.3% for PR-Wilson, and less than 12.0% for PR-UNIQUAC, indicating the reliability of these thermodynamic models for the present chemical system. [ABSTRACT FROM AUTHOR]

Based on Materials Studio and Aspen Plus, the reaction mechanism of producing benzene and styrene from ethane steam heat lysis was investigated through the addition reaction of free radicals + alkenes or free radicals + alkynes to form large free radicals and then through the cyclization and dehydrogenation of large free radicals to form aromatic hydrocarbons. It was found the thermal cracking of ethane had 2 paths to form benzene and 1 path to form styrene. The 1st path to form benzene is that the product ethylene form C2H3• through a chain transfer, then C2H3• and ethylene additively react to form 1-C4H7•-4, which then reacts with ethylene to form C6H11•, and finally, benzene is produced by dehydrogenation and transfer of C6H11•. The 2nd path to form benzene is that acetylene is produced by dehydrogenation of C2H3•, and then acetylene reacts via two sub-paths to form 1,3-C4H5•-4, which is cyclized to form C6H9•, and finally, benzene is formed through dehydrogenation and transfer. The path to form styrene is that 1,3-C4H5•-4 and 1,3-butadiene are cyclized to form C8H11•, and styrene is finally formed through dehydrogenation and chain transfer. Comparative analysis with industrial data showed there were 3 cycles in the ethane thermal cracking reaction network. The simulation data were well consistent with the industrial production data.