High-precision methane gas detection is of great importance in industrial safety, energy production and environmental protection, etc. However, in the existing measurement techniques, the methane gas concentration inf...High-precision methane gas detection is of great importance in industrial safety, energy production and environmental protection, etc. However, in the existing measurement techniques, the methane gas concentration information is susceptible to noise, which leads to its useful signal being drowned by noise. A fusion algorithm of variational modal decomposition(VMD) and improved wavelet threshold filtering is proposed, which is used in combination with tunable diode laser absorption spectroscopy(TDLAS) to implement a non-contact, high-resolution methane gas concentration detection. The fusion algorithm can perform noise reduction and further segmentation of the methane gas detection signal. And the simulation and experiment verify the effectiveness of the fusion algorithm, and the experimental results show that for the detection of air containing 10 ppm, 30 ppm, 60 ppm, 80 ppm, and 99 ppm methane, the errors are 12.75%, 8.18%, 3.37%, 2.46%, and 1.78%, respectively.展开更多
Although two moulds for methane gas in coal with the free state and adsorption state have been popularly considered, the derivation between the real methane gas state equation in coal and the perfect gas state equatio...Although two moulds for methane gas in coal with the free state and adsorption state have been popularly considered, the derivation between the real methane gas state equation in coal and the perfect gas state equation has been fuzzily considered and the mechanism of interaction for coal aromatics and methane gas molecules has not been understood. Then these problems have been discussed in this paper applied the principle of statistical thermo mechanics and quantum chemistry as well as based on the numerical calculating of experiential data in quantum chemistry. Therefore, it is revealed by research results that the experience state equation for real methane gas in coal, which is put forward in this paper, is closer to actual situation and the interaction process for methane gas adsorption on the surface of coal aromatics can be formulated by Morse potential function. Furthermore it is most stable through this research that the structural mould for methane gas molecule adsorption on the surface of coal nuclear with one gas molecule on top of another aromatics in regular triangle cone has been understood, and it is a physical adsorption for methane gas adsorption with single layer molecule on the surface of coal nuclear.展开更多
Gas leakage is an important consideration in natural systems that experience gas hydrate accumulation.A number of velocity models have been created to study hydrate-bearing sediments,including the BGTL theory,the weig...Gas leakage is an important consideration in natural systems that experience gas hydrate accumulation.A number of velocity models have been created to study hydrate-bearing sediments,including the BGTL theory,the weighted equation,the Wood equation,the K-T equation,and the effective medium theory.In previous work,we regarded water as the pore fluid,which meant its density and bulk modulus values were those of water.This approach ignores the presence of gas,which results in a biased calculation of the pore fluid's bulk modulus and density.To take into account the effect of gas on the elastic wave velocity,it is necessary to recalculate the bulk modulus and density of an equivalent medium.Thus,a high-pressure reactor device for simulating leakage systems was developed to establish the relationship between wave velocity and hydrate saturation in methane-flux mode.A comparison of the values calculated by the velocity model with the experimental data obtained in this study indicates that the effective medium theory(EMT,which considers gas effects)is more applicable than other models.For hydrate saturations of 10%–30%,the result ranges between EMT-B(homogenous gas distribution)and EMT-B(patchy gas distribution).For hydrate saturations of 30%–60%,the results are similar to those of the EMT-B(homogenous gas distribution)mode,whereas hydrate saturations of 60%–70%yield results similar to those of the EMT-A mode.For hydrate saturations greater than 80%,the experimental results are similar to those of the EMT-B mode.These results have significance for hydrate exploitation in the South China Sea.展开更多
A three-stage methane gas （CH4） reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 9...A three-stage methane gas （CH4） reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 925, and 950℃ for 120 min. Precipitation of the a-MnO2 nanorods was performed in the temperature range of 25-90℃with a constant reaction time of 90 min. The morphology and particle size of the products were determined from scanning electron microscope （SEM） images and X-ray diffraction （XRD） patterns. The BET and BJH of the products were found out by the surface area analyzer. Reduction results indicated that MnO-rich phase is significantly formed at 950℃ as MnO2 phase disappears. Precipitation results also showed an average diameter size of - 50 nm for the embedding a-MnO2 nanorods with BET surface area of 174 m^2/g.展开更多
The municipal solid waste (msw) is a source of landfill gas (msw)—with methane gas content. Preoccupations for landfill gas (msw) management date back since 1976 when, at a landfill (msw) in California (USA), it turn...The municipal solid waste (msw) is a source of landfill gas (msw)—with methane gas content. Preoccupations for landfill gas (msw) management date back since 1976 when, at a landfill (msw) in California (USA), it turned out practically that the landfill gas (msw) with methane gas content contains a gas with high caloric value that can be collected and used for economic purposes. The landfill gas (msw) contains methane gas (30% - 60% volume), carbon dioxide (45% - 50% volume), hydrogen sulfide and other gases. Methane gas, carbon dioxide, nitrous oxide and other gases are listed in Kyoto Protocol as high greenhouse gases. Their ecological-rational management is both a national and global preoccupation. In terms of greenhouse gases, especially methane gas, the landfill (msw) is held responsible for 3.5% - 5% of the total global greenhouse gases. Practically, the quantitative estimation of the methane gas in a municipal solid waste landfill can be done by measuring the landfill gas (msw) flow in an extraction-collection well. In Romania, a quantitative estimation relationship of methane gas from deposits (msw) was made, approaching the problem in a different way. This paper presents the calculation formula, the working algorithm, the municipal waste landfill equation and the NOMOGRAMA of a municipal solid waste landfill (msw). The NOMOGRAMA allows us to define the values for parameter -m- (number of months needed for an amount of municipal solid waste (msw) to degrade, starting with the year from which the landfill gas (msw) emission with methane gas content is calculated). Taking into account the environmental conditions for each location of municipal solid waste landfill, the calculation uses various indexes and approximations, while the fundamental parameter remains -m- defined by the NOMOGRAMA of the municipal solid waste landfill (msw). A municipal solid waste landfill (msw) is a conglomerate of waste with various biodegradation periods between 2 - 3 years and 5 - 10 - 30 years. Degradation of waste (msw) in to dissolved organic carbon will take place in a number of months defined -m- starting with the year from which the methane gas emission with the NOMOGRAMA of the municipal solid waste landfill (msw) is calculated. The -m- values for the year of the quantitative emission of methane gas can be also done analytically, which requires good experience in the ecologic-rational management of the municipal solid waste (msw).展开更多
The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in ...The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in the sediment is consumed progressively for the decomposition of the organic matter and anaerobic methane oxidation. Below the sulfate-methane interface, the methane concentration increases continuously with the depth. Based on the variation characters of the sulfate and methane concentration around the sulfate-methane interface, it is feasible to estimate the intensity of the methane flux, and thereafter to infer the possible occurrence of gas hydrate. The geochemical data of the pore water taken from the northern slope of the South China Sea show the sulfate-methane interface is relatively shallow, which indicates that this area has the high methane flux. It is considered that the high methane flux is most probably caused by the occurrence of underlying gas hydrate in the northern slope of the South China Sea.展开更多
We report a 1.65μm square-Fabry–Pérot[FP]coupled cavity semiconductor laser for methane gas detection.The laser output optical power can reach 7.4 m W with the side mode suppression ratio about 40 d B.The wavel...We report a 1.65μm square-Fabry–Pérot[FP]coupled cavity semiconductor laser for methane gas detection.The laser output optical power can reach 7.4 m W with the side mode suppression ratio about 40 d B.The wavelength tuning range is 2 nm by adjusting the FP cavity injection current,covering the methane absorption line at 1653.72 nm.The lasing wavelength can also be tuned by adjusting the square microcavity injection current or temperature,respectively.Methane gas detection is successfully demonstrated utilizing this laser.展开更多
Natural gas hydrates are mostly formed in low-permeability and fractured muddy sedimentary formations.Adding suitable nanoparticles to the drilling fluid system can improve its filtrate resistance and fracture pluggin...Natural gas hydrates are mostly formed in low-permeability and fractured muddy sedimentary formations.Adding suitable nanoparticles to the drilling fluid system can improve its filtrate resistance and fracture plugging,and effectively weaken the invasion of drilling fluid into the reservoir.However,it is likely that nanoparticles promote hydrate formation and accumulation in wellbores which will induce accidents.Therefore,this study investigated the effect of hydrophilic silica nanoparticles with particle sizes of 30 nm,60 nm,and 80 nm and concentrations of 0.5e4.0 wt%on hydrate formation during upward migration of methane gas using a dynamic simulation system for hydrate formation in a wellbore.The experimental results show that under the condition of methane gas migration,hydrophilic silica nanoparticles inhibit hydrate formation.The inhibition effect increased with the growth in the particle size under a constant concentration,whereas it first increased and then decreased with increasing nanoparticle concentration under a constant particle size.The strongest inhibition effect was observed at a hydrophilic silica nanoparticle concentration of 2.0 wt%.The influence of hydrophilic silica nanoparticles on hydrate formation may be mainly determined by their hydrophilic properties,heat and mass transfer,and gas migration in the wellbore.Our research indicates that hydrophilic silica nanoparticles can be added to hydrate drilling fluid systems if their concentration can be properly controlled.展开更多
Oil and gas pipeline transportation,as a relatively safe way of oil and gas transportation,undertakes most of the transportation tasks of crude oil and natural gas.Oil and gas pipeline accidents affect a wide range of...Oil and gas pipeline transportation,as a relatively safe way of oil and gas transportation,undertakes most of the transportation tasks of crude oil and natural gas.Oil and gas pipeline accidents affect a wide range of consequences.Therefore,the oil and gas pipeline leakage detection is paid more and more attention.In this paper,ultra-low power methane gas sensor is selected to collect methane gas concentration in the air,and wireless network technology is used to build a wireless network sensor system with 4G function.Through the sensor distribution along the pipeline,it can intuitively and accurately judge whether there is a micro-leakage in the pipeline,and understand the diffusion situation after the leakage.The sensor system has high reliability and stability,and has high value of popularization and application.展开更多
With the enormous increase in the demand for crude oil,and decrease in the resources of conventional oil reservoirs,there is a great need to understand heavy or foamy oil-gas drive mechanism to maximize the oil and ga...With the enormous increase in the demand for crude oil,and decrease in the resources of conventional oil reservoirs,there is a great need to understand heavy or foamy oil-gas drive mechanism to maximize the oil and gas production.To analyze the real movement of non-viscous heavy oil flow,the characteristic features of the oil-gas mixture has to be estimated to forecast the future potential supply from a heavy oil reservoir.An important question in heavy oil flow under solution gas drive is whether the behaviour of depletion tests can be simulated to model the heavy oil flow behaviour.The main objective of this research is to develop a reliable numerical model for modelling heavy oil flow calibrated with controlled solution gas drive experiments,and that makes a novelty in this manuscript.In this paper,CMG-STARS model which is capable of simulating solution gas drive tests that matched the research experiments.This heavy oil recovery model can determine the relative permeability curves for oil and gas in the dualphase system using Corey’s relations.At a depletion rate of 0.0418 psi/min,the maximum cumulative oil and gas production was observed to be 13,000 cm^(3)and 8500 cm^(3),respectively.The results from the bottom hole pressure and the block pressure simulation runs indicate that the fluid properties such as surface tension plays a significant role in the gas bubble formation.These results are promising,and helps to understand the complex behaviour of heavy oil reservoirs and thus can improve heavy oil recovery.展开更多
Background： Modification of chemical composition of diets fed to dairy cows might be a good strategy to reduce methane（CH4） production in the rumen. Notable reductions of CH4 production compared to conventional hig...Background： Modification of chemical composition of diets fed to dairy cows might be a good strategy to reduce methane（CH4） production in the rumen. Notable reductions of CH4 production compared to conventional highroughages rations were more frequently observed for very concentrated diets or when fat supplements were used. In these cases, the reduction in the gas emission was mainly a consequence of an overall impairment of rumen function with a reduction of fiber digestibility. These strategies do not always comply with feeding standards used in intensive dairy farms and they are usually not applied owing to the risks of negative health and economic consequences.Thus, the present study evaluated the effects of seven commercial diets with contents of neutral detergent fiber（NDF）,protein and lipids ranging 325 to 435 g/kg DM, 115 to 194 g/kg DM, and 26 to 61 g/kg DM, respectively, on in vitro degradability, gas（GP）, and CH4 production.Results： In this experiment, changes in the dietary content of NDF, crude protein（CP） and lipids were always obtained at the expense or in favor of starch. A decreased of the dietary NDF content increased NDF（NDFd） and true DM（TDMd） degradability, and increased CH4 production per g of incubated DM（P 〈 0.001）, but not that per g of TDMd. An increase of the dietary CP level did not change in vitro NDFd and TDMd, decreased GP per g of incubated DM（P 〈 0.001）, but CH4 production per g of TDMd was not affected. An increased dietary lipid content reduced NDFd, TDMd,and GP per g of incubated DM, but it had no consequence on CH4 production per g of TDMd.Conclusions： It was concluded that, under commercial conditions, changes in dietary composition would produce small or negligible alterations of CH4 production per unit of TDMd, but greater differences in GP and CH4 production would be expected when these amounts are expressed per unit of DM intake. The use of TDMd as a standardizing parameter is proposed to account for possible difference in DM intake and productivity.展开更多
Effects of some methodological factors on in vitro measures of gas production（GP, mL/g DM）, CH4production（mL/g DM） and proportion（% CH4 on total GP） were investigated by meta-analysis. These factors were conside...Effects of some methodological factors on in vitro measures of gas production（GP, mL/g DM）, CH4production（mL/g DM） and proportion（% CH4 on total GP） were investigated by meta-analysis. These factors were considered：pressure in the GP equipment（0 = constant; 1 = increasing）, incubation time（0 = 24; 1 = ≥ 48 h）, time of rumen fluid collection（0 = before feeding; 1 = after feeding of donor animals）, donor species of rumen fluid（0 = sheep; 1 =bovine）, presence of N in the buffer solution（0 = presence; 1 = absence）, and ratio between amount of buffered rumen fluid and feed sample（BRF/FS; 0 = ≤ 130 mL/g DM; 1 = 130–140 mL/g DM; 2 = ≥ 140 mL/g DM）. The NDF content of feed sample incubated（NDF） was considered as a continuous variable. From an initial database of 105 papers, 58 were discarded because one of the above-mentioned factors was not stated. After discarding 17 papers,the final dataset comprised 30 papers（339 observations）. A preliminary mixed model analysis was carried out on experimental data considering the study as random factor. Variables adjusted for study effect were analyzed using a backward stepwise analysis including the above-mentioned variables. The analysis showed that the extension of incubation time and reduction of NDF increased GP and CH4 values. Values of GP and CH4 also increased when rumen fluid was collected after feeding compared to before feeding（＋26.4 and ＋9.0 mL/g DM, for GP and CH4）,from bovine compared to sheep（＋32.8 and ＋5.2 mL/g DM, for GP and CH4）, and when the buffer solution did not contain N（＋24.7 and ＋6.7 mL/g DM for GP and CH4）. The increase of BRF/FS ratio enhanced GP and CH4production（＋7.7 and ＋3.3 mL/g DM per each class of increase, respectively）. In vitro techniques for measuring GP and CH4 production are mostly used as screening methods, thus a full standardization of such techniques is not feasible. However, a greater harmonization of analytical procedures（i.e., a reduction in the number of available protocols） would be useful to facilitate comparison between results of different experiments.展开更多
An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydr...An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.展开更多
A low-viscosity emulsion of crude oil in water can be believed to be the bulk of a flow regime in a pipeline.To differentiate which crude oil would and which would not counter the blockage of flow due to gas hydrate f...A low-viscosity emulsion of crude oil in water can be believed to be the bulk of a flow regime in a pipeline.To differentiate which crude oil would and which would not counter the blockage of flow due to gas hydrate formation in flow channels,varying amount of crude oil in water emulsion without any other extraneous additives has undergone methane gas hydrate formation in an autoclave cell.Crude oil was able to thermodynamically inhibit the gas hydrate formation as observed from its hydrate stability zone.The normalized rate of hydrate formation in the emulsion has been calculated from an illustrative chemical affinity model,which showed a decrease in the methane consumption（decreased normalized rate constant） with an increase in the oil content in the emulsion.Fourier transform infrared spectroscopy（FTIR） of the emulsion and characteristic properties of the crude oil have been used to find the chemical component that could be pivotal in selfinhibitory characteristic of the crude oil collected from Ankleshwar,India,against a situation of clogged flow due to formation of gas hydrate and establish flow assurance.展开更多
Based upon an analysis of global energy developing trend,a discussion was made on the natural gas developing trend in China with the following pre-estimating results from multiple perspectives.(1)Natural gas will be s...Based upon an analysis of global energy developing trend,a discussion was made on the natural gas developing trend in China with the following pre-estimating results from multiple perspectives.(1)Natural gas will be strongly demanded and in 2050 it will be up to 650-700 billion cubic meters(bcm).(2)The high-medium-low peaking scenarios of natural gas production rate in 2030 will be 180 bcm,200 bcm and 220 bcm,respectively.(3)Up till now,the supply capacity of inland pipeline gas will be about 160 bcm.(4)LNG will be the main approach to filling the gap in the natural gas demand.(5)When the peak value of domestic production and pipeline gas is definite,LNG and storage gas will play an important role in the whole natural gas industrial chain in the future.Also,according to the basic condition of China,the strategies for future natural gas development were presented as follows:to enhance the capabilities of domestic gas productivity,pipeline transportation,gas storage(such as LNG terminals,UGS,etc.);to set up an early warning system for oil&gas peak security consumption with detailed supply and demand information based upon AI technology and big data analysis;to make breakthroughs in coal cleaning and new energy production technologies for lack of non-renewable oil and gas resources;and to get a better understanding of global energy developing trend and have an omni-direction strategic layout for national energy security thus to quicken the pace of a new tripartite confrontation era of coal,petroleum and new energy sources.展开更多
Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic （reversed A^2O） and anaerobic/anoxic/aerobic （A^2O）, were selected to investigate the emission characteristics of gr...Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic （reversed A^2O） and anaerobic/anoxic/aerobic （A^2O）, were selected to investigate the emission characteristics of greenhouse gases （GHG）, including carbon dioxide （CO2）, methane （CH4） and nitrous oxide （N2O）. Results showed that although the processes were different, the units presenting high GHG emission fluxes were remarkably similar, namely the highest CO2 and N2O emission fluxes occurred in the aerobic areas, and the highest CH4 emission fluxes occurred in the grit tanks. The GHG emission amount of each unit can be calculated from its area and GHG emission flux. The calculation results revealed that the maximum emission amounts of CO2, CH4 and N2O in the three wastewater treatment processes appeared in the aerobic areas in all cases. Theoretically, CH4 should be produced in anaerobic conditions, rather than aerobic conditions. However, results in this study showed that the CH4 emission fluxes in the forepart of the aerobic area were distinctly higher than in the anaerobic area. The situation for N2O was similar to that of CH4： the N2O emission flux in the aerobic area was also higher than that in the anoxic area. Through analysis of the GHG mass balance, it was found that the flow of dissolved GHG in the wastewater treatment processes and aerators may be the main reason for this phenomenon. Based on the monitoring and calculation results, GHG emission factors for the three wastewater treatment processes were determined. The A^2O process had the highest CO2 emission factor of 319.3 g CO2/kg CODremoved, and the highest CH4 and N2O emission factors of 3.3 g CH4/kg CODremoved and 3.6 g N2O/kg TNremoved were observed in the Orbal oxidation ditch process.展开更多
Multiple coal seams widely develop in the deep Chinese coal-bearing strata. Ground in situ stress and coal seam gas pressure increase continuously with the increase of the mining depth, and coal and gas outburst disas...Multiple coal seams widely develop in the deep Chinese coal-bearing strata. Ground in situ stress and coal seam gas pressure increase continuously with the increase of the mining depth, and coal and gas outburst disasters become increasingly severe. When the coal is very deep, the gas content and pressure will elevate and thus coal seams tends to outburst-prone seams. The safety and economics of exploited firstmined coal seams are tremendously restricted. Meanwhile, the multiple seams occurrence conditions resulted in different methane pressure systems in the coal-bearing strata, which made the reservoir reconstruction of coal difficult. Given the characteristics of low saturation, low permeability, strong anisotropy and soft coal of Chinese coal seams, a single hydraulic fracturing surface well for reservoir reconstruction to pre-drain the coalbed methane(CBM) of multiple seams concurrently under the different gas pressure systems has not yet gained any breakthroughs. Based on analyses of the main features of deep CBM reservoirs in China, current gas control methods and the existing challenges in deep and multiple seams, we proposed a new technology for deep CBM reservoir reconstruction to realize simultaneous high-efficiency coal mining and gas extraction. In particular, we determined the first-mined seam according to the principles of effectiveness and economics, and used hydraulic fracturing surface well to reconstruct the first-mined seam which enlarges the selection range of the first-mined seam. During the process of mining first-mined seam, adjacent coal seams could be reconstructed under the mining effect which promoted high-efficiency pressure relief gas extraction by using spatial and comprehensive gas drainage methods(combination of underground and ground CBM extraction methods). A typical integrated reservoir reconstruction technology, ‘‘One well for triple use", was detailed introduced and successfully applied in the Luling coal mine. The application showed that the proposed technology could effectively promote coal mining safety and simultaneously high-efficiency gas extraction.展开更多
A series of Fe2O3/Al2O3, Fe2O3/CeO2, Ce0.7Zr0.3O2, and Fe2O3/Ce1-xZrxO2（x = 0.1–0.4） oxides was prepared and their physicochemical features were investigated by X-ray diffraction（XRD）, transmission electron micro...A series of Fe2O3/Al2O3, Fe2O3/CeO2, Ce0.7Zr0.3O2, and Fe2O3/Ce1-xZrxO2（x = 0.1–0.4） oxides was prepared and their physicochemical features were investigated by X-ray diffraction（XRD）, transmission electron microscope（TEM）, and H2-temperature-programmed reduction（H2-TPR） techniques. The gas–solid reactions between these oxides and methane for syngas generation as well as the catalytic performance for selective oxidation of carbon deposition in O2-enriched atmosphere were investigated in detail. The results show that the samples with the presence of Fe2O3show much higher activity for methane oxidation compared with the Ce0.7Zr0.3O2solid solution,while the CeO2-contained samples represent higher CO selectively in methane oxidation than the Fe2O3/Al2O3sample. This suggests that the iron species should be the active sites for methane activation, and the cerium oxides provide the oxygen source for the selective oxidation of the activated methane to syngas during the reaction between methane and Fe2O3/Ce0.7Zr0.3O2. For the oxidation process of the carbon deposition, the CeO2-containing samples show much higher CO selectivity than the Fe2O3/Al2O3sample, which indicates that the cerium species should play a very important role in catalyzing the carbon selective oxidation to CO. The presence of the Ce–Zr–O solid solution could induce the growth direction of the carbonfilament, resulting in a loose contact between the carbon filament and the catalyst. This results in abundant exposed active sites for catalyzing carbon oxidation, strongly improving the oxidation rate of the carbon deposition over this sample. In addition, the Fe2O3/Ce0.7Zr0.3O2also represents much higher selectivity（ca. 97 %） for the conversion of carbon to CO than the Fe2O3/CeO2sample, which can be attributed to the higher concentration of reduced cerium sites on this sample. The increase of the Zr content in the Fe2O3/Ce1-xZrxO2samples could improve the reactivity of the materials for methane oxidation, but it also reduces the selectivity for CO formation.展开更多
Surface water methane （CH4） and nitrous oxide （N20） concentrations and fluxes were investigated in two subtropical coastal embayments （Bramble Bay and Deception Bay, which are part of the greater Moreton Bay, Aus...Surface water methane （CH4） and nitrous oxide （N20） concentrations and fluxes were investigated in two subtropical coastal embayments （Bramble Bay and Deception Bay, which are part of the greater Moreton Bay, Australia）. Measurements were done at 23 stations in seven campaigns covering different seasons during 2010-2012. Water-air fluxes were estimated using the Thin Boundary Layer approach with a combination of wind and currents-based models for the estimation of the gas transfer velocities. The two bays were strong sources of both CH4 and N2O with no significant differences in the degree of saturation of both gases between them during all measurement campaigns. Both CH4 and N2O concentrations had strong temporal but minimal spatial variability in both bays. During the seven seasons, CH4 varied between 500% and 4000% saturation while N2O varied between 128 and 255% in the two bays. Average seasonal CH4 fluxes for the two bays varied between 0.5 ± 0.2 and 6.0 ± 1.5 mg CH4/（m^2.day） while N20 varied between 0.4 ± 0.1 and 1.6 ± 0.6 mg N2O/（m^2-day）. Weighted emissions （t CO2-e） were 63%-90% N2O dominated implying that a reduction in N2O inputs and/or nitrogen availability in the bays may significantly reduce the bays＇ greenhouse gas （GHG） budget. Emissions data for tropical and subtropical systems is still scarce. This work found subtropical bays to be significant aquatic sources of both CH4 and N2O and puts the estimated fluxes into the global context with measurements done from other climatic regions.展开更多
Sawahlunto(SL-02) and Sangatta(KD-04) coals were analyzed for the presence of aliphatic hydrocarbon fraction biomarkers to assess their organic geochemistry and its implications for selecting exploration strategies fo...Sawahlunto(SL-02) and Sangatta(KD-04) coals were analyzed for the presence of aliphatic hydrocarbon fraction biomarkers to assess their organic geochemistry and its implications for selecting exploration strategies for coal bed methane(CBM). Structural identification using the gas chromatography-mass spectrometry(GC-MS) method revealed the distribution of n-alkanes, isoprenoids, sesquiterpenoids,and triterpenoids. The organic matter in both coal samples originated from higher terrigenous plants, as indicated by the dominance of long-chain n-alkanes, carbon preference index(CPI) values greater than 1,low vs. high carbon preference index(LHCPI) values less than 1, terrigenous/aquatic ratio(TAR) values over 5, and the dominance of 8β(H)-homodrimane over 8β(H)-drimane. An oxic depositional environment is suggested by a Pr/Ph ratio greater than 1, the presence of hopanes(C31 and C32), and the low abundance of 8β(H)-drimane in both samples. CPI values greater than 1, OEP values greater than 1, LHCPI values less than 1, the abundance of 17a(H),21β(H)-homohopane(22S) compared with that of17a(H),21β(H)-homohopane(22R), and the presence of several unsaturated biomarkers in the KD-04sample, such as olean-12-ene, olean-18-ene, and neohop-13(18)-ene, indicate that the coal is relatively immature. A cross plot of the Pr/n-C17 ratio against the Ph/n-C18 ratio in the Hunt diagram classifies the sample as humic coal derived from higher terrigenous plants, deposited in an oxic environment, and as a type III kerogen with gas-generating potential in both the SL-02 and KD-04 coals.These biomarker data and parameters are highly relevant for methane gas miners in SL-02 coal from the Sawahlunto coal mine, West Sumatra, and KD-04 coal from the Sangatta coal mine, East Kalimantan. The CBM is estimated to have a biogenic origin.展开更多
基金supported by the Project Grant from Heilongjiang Bayi Agricultural Reclamation University,Heilongjiang,China (No.XDB201813)。
文摘High-precision methane gas detection is of great importance in industrial safety, energy production and environmental protection, etc. However, in the existing measurement techniques, the methane gas concentration information is susceptible to noise, which leads to its useful signal being drowned by noise. A fusion algorithm of variational modal decomposition(VMD) and improved wavelet threshold filtering is proposed, which is used in combination with tunable diode laser absorption spectroscopy(TDLAS) to implement a non-contact, high-resolution methane gas concentration detection. The fusion algorithm can perform noise reduction and further segmentation of the methane gas detection signal. And the simulation and experiment verify the effectiveness of the fusion algorithm, and the experimental results show that for the detection of air containing 10 ppm, 30 ppm, 60 ppm, 80 ppm, and 99 ppm methane, the errors are 12.75%, 8.18%, 3.37%, 2.46%, and 1.78%, respectively.
文摘Although two moulds for methane gas in coal with the free state and adsorption state have been popularly considered, the derivation between the real methane gas state equation in coal and the perfect gas state equation has been fuzzily considered and the mechanism of interaction for coal aromatics and methane gas molecules has not been understood. Then these problems have been discussed in this paper applied the principle of statistical thermo mechanics and quantum chemistry as well as based on the numerical calculating of experiential data in quantum chemistry. Therefore, it is revealed by research results that the experience state equation for real methane gas in coal, which is put forward in this paper, is closer to actual situation and the interaction process for methane gas adsorption on the surface of coal aromatics can be formulated by Morse potential function. Furthermore it is most stable through this research that the structural mould for methane gas molecule adsorption on the surface of coal nuclear with one gas molecule on top of another aromatics in regular triangle cone has been understood, and it is a physical adsorption for methane gas adsorption with single layer molecule on the surface of coal nuclear.
基金supported financially by the National Key R&D Program of China(No.2017YFC0307600)the Qingdao National Laboratory for Marine Science and Technology(No.QNLM2016ORP0207)+3 种基金the National Natural Science Foundation of China(No.41906067)the China Postdoctoral Science Foundation(No.2018M632634)the Natural Science Foundation of Shandong Province of China(No.ZR2019BD051)the Marine Geological Survey Program(Nos.DD20190221 and DD20190231)。
文摘Gas leakage is an important consideration in natural systems that experience gas hydrate accumulation.A number of velocity models have been created to study hydrate-bearing sediments,including the BGTL theory,the weighted equation,the Wood equation,the K-T equation,and the effective medium theory.In previous work,we regarded water as the pore fluid,which meant its density and bulk modulus values were those of water.This approach ignores the presence of gas,which results in a biased calculation of the pore fluid's bulk modulus and density.To take into account the effect of gas on the elastic wave velocity,it is necessary to recalculate the bulk modulus and density of an equivalent medium.Thus,a high-pressure reactor device for simulating leakage systems was developed to establish the relationship between wave velocity and hydrate saturation in methane-flux mode.A comparison of the values calculated by the velocity model with the experimental data obtained in this study indicates that the effective medium theory(EMT,which considers gas effects)is more applicable than other models.For hydrate saturations of 10%–30%,the result ranges between EMT-B(homogenous gas distribution)and EMT-B(patchy gas distribution).For hydrate saturations of 30%–60%,the results are similar to those of the EMT-B(homogenous gas distribution)mode,whereas hydrate saturations of 60%–70%yield results similar to those of the EMT-A mode.For hydrate saturations greater than 80%,the experimental results are similar to those of the EMT-B mode.These results have significance for hydrate exploitation in the South China Sea.
基金financial supports of the Islamic Azad University of Zanjan
文摘A three-stage methane gas （CH4） reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 925, and 950℃ for 120 min. Precipitation of the a-MnO2 nanorods was performed in the temperature range of 25-90℃with a constant reaction time of 90 min. The morphology and particle size of the products were determined from scanning electron microscope （SEM） images and X-ray diffraction （XRD） patterns. The BET and BJH of the products were found out by the surface area analyzer. Reduction results indicated that MnO-rich phase is significantly formed at 950℃ as MnO2 phase disappears. Precipitation results also showed an average diameter size of - 50 nm for the embedding a-MnO2 nanorods with BET surface area of 174 m^2/g.
文摘The municipal solid waste (msw) is a source of landfill gas (msw)—with methane gas content. Preoccupations for landfill gas (msw) management date back since 1976 when, at a landfill (msw) in California (USA), it turned out practically that the landfill gas (msw) with methane gas content contains a gas with high caloric value that can be collected and used for economic purposes. The landfill gas (msw) contains methane gas (30% - 60% volume), carbon dioxide (45% - 50% volume), hydrogen sulfide and other gases. Methane gas, carbon dioxide, nitrous oxide and other gases are listed in Kyoto Protocol as high greenhouse gases. Their ecological-rational management is both a national and global preoccupation. In terms of greenhouse gases, especially methane gas, the landfill (msw) is held responsible for 3.5% - 5% of the total global greenhouse gases. Practically, the quantitative estimation of the methane gas in a municipal solid waste landfill can be done by measuring the landfill gas (msw) flow in an extraction-collection well. In Romania, a quantitative estimation relationship of methane gas from deposits (msw) was made, approaching the problem in a different way. This paper presents the calculation formula, the working algorithm, the municipal waste landfill equation and the NOMOGRAMA of a municipal solid waste landfill (msw). The NOMOGRAMA allows us to define the values for parameter -m- (number of months needed for an amount of municipal solid waste (msw) to degrade, starting with the year from which the landfill gas (msw) emission with methane gas content is calculated). Taking into account the environmental conditions for each location of municipal solid waste landfill, the calculation uses various indexes and approximations, while the fundamental parameter remains -m- defined by the NOMOGRAMA of the municipal solid waste landfill (msw). A municipal solid waste landfill (msw) is a conglomerate of waste with various biodegradation periods between 2 - 3 years and 5 - 10 - 30 years. Degradation of waste (msw) in to dissolved organic carbon will take place in a number of months defined -m- starting with the year from which the methane gas emission with the NOMOGRAMA of the municipal solid waste landfill (msw) is calculated. The -m- values for the year of the quantitative emission of methane gas can be also done analytically, which requires good experience in the ecologic-rational management of the municipal solid waste (msw).
文摘The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in the sediment is consumed progressively for the decomposition of the organic matter and anaerobic methane oxidation. Below the sulfate-methane interface, the methane concentration increases continuously with the depth. Based on the variation characters of the sulfate and methane concentration around the sulfate-methane interface, it is feasible to estimate the intensity of the methane flux, and thereafter to infer the possible occurrence of gas hydrate. The geochemical data of the pore water taken from the northern slope of the South China Sea show the sulfate-methane interface is relatively shallow, which indicates that this area has the high methane flux. It is considered that the high methane flux is most probably caused by the occurrence of underlying gas hydrate in the northern slope of the South China Sea.
基金supported by the National Key R&D Program of China(No.2017YFB0405301)。
文摘We report a 1.65μm square-Fabry–Pérot[FP]coupled cavity semiconductor laser for methane gas detection.The laser output optical power can reach 7.4 m W with the side mode suppression ratio about 40 d B.The wavelength tuning range is 2 nm by adjusting the FP cavity injection current,covering the methane absorption line at 1653.72 nm.The lasing wavelength can also be tuned by adjusting the square microcavity injection current or temperature,respectively.Methane gas detection is successfully demonstrated utilizing this laser.
基金the National Natural Science Foundation of China(Grant No.41672367,51704266,and 51874263)the National Key Research and Development Program of China(No.2018YFE0126400)+1 种基金the Special Project for Marine Economic Development(Six Major Marine Industries)of Department of Natural Resources of Guangdong Province(GDNRC[2020]047)the Fundamental Research Funds for National Universities,China University of Geosciences(Wuhan)(Grant No.CUGGC09).
文摘Natural gas hydrates are mostly formed in low-permeability and fractured muddy sedimentary formations.Adding suitable nanoparticles to the drilling fluid system can improve its filtrate resistance and fracture plugging,and effectively weaken the invasion of drilling fluid into the reservoir.However,it is likely that nanoparticles promote hydrate formation and accumulation in wellbores which will induce accidents.Therefore,this study investigated the effect of hydrophilic silica nanoparticles with particle sizes of 30 nm,60 nm,and 80 nm and concentrations of 0.5e4.0 wt%on hydrate formation during upward migration of methane gas using a dynamic simulation system for hydrate formation in a wellbore.The experimental results show that under the condition of methane gas migration,hydrophilic silica nanoparticles inhibit hydrate formation.The inhibition effect increased with the growth in the particle size under a constant concentration,whereas it first increased and then decreased with increasing nanoparticle concentration under a constant particle size.The strongest inhibition effect was observed at a hydrophilic silica nanoparticle concentration of 2.0 wt%.The influence of hydrophilic silica nanoparticles on hydrate formation may be mainly determined by their hydrophilic properties,heat and mass transfer,and gas migration in the wellbore.Our research indicates that hydrophilic silica nanoparticles can be added to hydrate drilling fluid systems if their concentration can be properly controlled.
基金The 2019 Ministry of Education industry-university cooperation collaborative education project“Research on the Construction of Economics and Management Professional Data Analysis Laboratory”(Project number:201902077020)。
文摘Oil and gas pipeline transportation,as a relatively safe way of oil and gas transportation,undertakes most of the transportation tasks of crude oil and natural gas.Oil and gas pipeline accidents affect a wide range of consequences.Therefore,the oil and gas pipeline leakage detection is paid more and more attention.In this paper,ultra-low power methane gas sensor is selected to collect methane gas concentration in the air,and wireless network technology is used to build a wireless network sensor system with 4G function.Through the sensor distribution along the pipeline,it can intuitively and accurately judge whether there is a micro-leakage in the pipeline,and understand the diffusion situation after the leakage.The sensor system has high reliability and stability,and has high value of popularization and application.
文摘With the enormous increase in the demand for crude oil,and decrease in the resources of conventional oil reservoirs,there is a great need to understand heavy or foamy oil-gas drive mechanism to maximize the oil and gas production.To analyze the real movement of non-viscous heavy oil flow,the characteristic features of the oil-gas mixture has to be estimated to forecast the future potential supply from a heavy oil reservoir.An important question in heavy oil flow under solution gas drive is whether the behaviour of depletion tests can be simulated to model the heavy oil flow behaviour.The main objective of this research is to develop a reliable numerical model for modelling heavy oil flow calibrated with controlled solution gas drive experiments,and that makes a novelty in this manuscript.In this paper,CMG-STARS model which is capable of simulating solution gas drive tests that matched the research experiments.This heavy oil recovery model can determine the relative permeability curves for oil and gas in the dualphase system using Corey’s relations.At a depletion rate of 0.0418 psi/min,the maximum cumulative oil and gas production was observed to be 13,000 cm^(3)and 8500 cm^(3),respectively.The results from the bottom hole pressure and the block pressure simulation runs indicate that the fluid properties such as surface tension plays a significant role in the gas bubble formation.These results are promising,and helps to understand the complex behaviour of heavy oil reservoirs and thus can improve heavy oil recovery.
基金the project “ARCHAEA - Feeding strategies to reduce methane emissions from dairy cows” – Veneto Region Rural Development Programme (RDP) 2007–2013
文摘Background： Modification of chemical composition of diets fed to dairy cows might be a good strategy to reduce methane（CH4） production in the rumen. Notable reductions of CH4 production compared to conventional highroughages rations were more frequently observed for very concentrated diets or when fat supplements were used. In these cases, the reduction in the gas emission was mainly a consequence of an overall impairment of rumen function with a reduction of fiber digestibility. These strategies do not always comply with feeding standards used in intensive dairy farms and they are usually not applied owing to the risks of negative health and economic consequences.Thus, the present study evaluated the effects of seven commercial diets with contents of neutral detergent fiber（NDF）,protein and lipids ranging 325 to 435 g/kg DM, 115 to 194 g/kg DM, and 26 to 61 g/kg DM, respectively, on in vitro degradability, gas（GP）, and CH4 production.Results： In this experiment, changes in the dietary content of NDF, crude protein（CP） and lipids were always obtained at the expense or in favor of starch. A decreased of the dietary NDF content increased NDF（NDFd） and true DM（TDMd） degradability, and increased CH4 production per g of incubated DM（P 〈 0.001）, but not that per g of TDMd. An increase of the dietary CP level did not change in vitro NDFd and TDMd, decreased GP per g of incubated DM（P 〈 0.001）, but CH4 production per g of TDMd was not affected. An increased dietary lipid content reduced NDFd, TDMd,and GP per g of incubated DM, but it had no consequence on CH4 production per g of TDMd.Conclusions： It was concluded that, under commercial conditions, changes in dietary composition would produce small or negligible alterations of CH4 production per unit of TDMd, but greater differences in GP and CH4 production would be expected when these amounts are expressed per unit of DM intake. The use of TDMd as a standardizing parameter is proposed to account for possible difference in DM intake and productivity.
基金financed by the project “ARCHAEA- Feeding strategies to reduce methane emissions from dairy cows,”Veneto Region Rural Development Programme (RDP) 2007–2013 “Progetto di Ateneo cod. CPDA 155250”, University of Padova, Italy
文摘Effects of some methodological factors on in vitro measures of gas production（GP, mL/g DM）, CH4production（mL/g DM） and proportion（% CH4 on total GP） were investigated by meta-analysis. These factors were considered：pressure in the GP equipment（0 = constant; 1 = increasing）, incubation time（0 = 24; 1 = ≥ 48 h）, time of rumen fluid collection（0 = before feeding; 1 = after feeding of donor animals）, donor species of rumen fluid（0 = sheep; 1 =bovine）, presence of N in the buffer solution（0 = presence; 1 = absence）, and ratio between amount of buffered rumen fluid and feed sample（BRF/FS; 0 = ≤ 130 mL/g DM; 1 = 130–140 mL/g DM; 2 = ≥ 140 mL/g DM）. The NDF content of feed sample incubated（NDF） was considered as a continuous variable. From an initial database of 105 papers, 58 were discarded because one of the above-mentioned factors was not stated. After discarding 17 papers,the final dataset comprised 30 papers（339 observations）. A preliminary mixed model analysis was carried out on experimental data considering the study as random factor. Variables adjusted for study effect were analyzed using a backward stepwise analysis including the above-mentioned variables. The analysis showed that the extension of incubation time and reduction of NDF increased GP and CH4 values. Values of GP and CH4 also increased when rumen fluid was collected after feeding compared to before feeding（＋26.4 and ＋9.0 mL/g DM, for GP and CH4）,from bovine compared to sheep（＋32.8 and ＋5.2 mL/g DM, for GP and CH4）, and when the buffer solution did not contain N（＋24.7 and ＋6.7 mL/g DM for GP and CH4）. The increase of BRF/FS ratio enhanced GP and CH4production（＋7.7 and ＋3.3 mL/g DM per each class of increase, respectively）. In vitro techniques for measuring GP and CH4 production are mostly used as screening methods, thus a full standardization of such techniques is not feasible. However, a greater harmonization of analytical procedures（i.e., a reduction in the number of available protocols） would be useful to facilitate comparison between results of different experiments.
基金financially supported by the Joint Fund of Coal, set up by National Natural Science Foundation of China and Shenhua Co., Ltd.(U1261104)the National Natural Science Foundation of China (21276041)+3 种基金the Program for New Century Excellent Talents in University (NCET-12-0079)the Natural Science Foundation of Liaoning Province (2015020200)the Fundamental Research Funds for the Central Universities (DUT15LK41)the Science and Technology Development Program of Hangzhou (20130533B14)~~
文摘An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.
基金the financial assistance provided by University Grants Commission, New Delhi, India, under Special Assistance Program (SAP) to the Department of Petroleum Engineering, Indian School of Mines, Dhanbad, India
文摘A low-viscosity emulsion of crude oil in water can be believed to be the bulk of a flow regime in a pipeline.To differentiate which crude oil would and which would not counter the blockage of flow due to gas hydrate formation in flow channels,varying amount of crude oil in water emulsion without any other extraneous additives has undergone methane gas hydrate formation in an autoclave cell.Crude oil was able to thermodynamically inhibit the gas hydrate formation as observed from its hydrate stability zone.The normalized rate of hydrate formation in the emulsion has been calculated from an illustrative chemical affinity model,which showed a decrease in the methane consumption（decreased normalized rate constant） with an increase in the oil content in the emulsion.Fourier transform infrared spectroscopy（FTIR） of the emulsion and characteristic properties of the crude oil have been used to find the chemical component that could be pivotal in selfinhibitory characteristic of the crude oil collected from Ankleshwar,India,against a situation of clogged flow due to formation of gas hydrate and establish flow assurance.
基金Project supported by National Major Science and Technology Project(No.2016ZX05047 and 2016ZX05015)National Program on Key Basic Research Project(973 Program)(No.2014CB239000).
文摘Based upon an analysis of global energy developing trend,a discussion was made on the natural gas developing trend in China with the following pre-estimating results from multiple perspectives.(1)Natural gas will be strongly demanded and in 2050 it will be up to 650-700 billion cubic meters(bcm).(2)The high-medium-low peaking scenarios of natural gas production rate in 2030 will be 180 bcm,200 bcm and 220 bcm,respectively.(3)Up till now,the supply capacity of inland pipeline gas will be about 160 bcm.(4)LNG will be the main approach to filling the gap in the natural gas demand.(5)When the peak value of domestic production and pipeline gas is definite,LNG and storage gas will play an important role in the whole natural gas industrial chain in the future.Also,according to the basic condition of China,the strategies for future natural gas development were presented as follows:to enhance the capabilities of domestic gas productivity,pipeline transportation,gas storage(such as LNG terminals,UGS,etc.);to set up an early warning system for oil&gas peak security consumption with detailed supply and demand information based upon AI technology and big data analysis;to make breakthroughs in coal cleaning and new energy production technologies for lack of non-renewable oil and gas resources;and to get a better understanding of global energy developing trend and have an omni-direction strategic layout for national energy security thus to quicken the pace of a new tripartite confrontation era of coal,petroleum and new energy sources.
基金supported by the National Natural Science Foundation of China (No. 51138009)
文摘Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic （reversed A^2O） and anaerobic/anoxic/aerobic （A^2O）, were selected to investigate the emission characteristics of greenhouse gases （GHG）, including carbon dioxide （CO2）, methane （CH4） and nitrous oxide （N2O）. Results showed that although the processes were different, the units presenting high GHG emission fluxes were remarkably similar, namely the highest CO2 and N2O emission fluxes occurred in the aerobic areas, and the highest CH4 emission fluxes occurred in the grit tanks. The GHG emission amount of each unit can be calculated from its area and GHG emission flux. The calculation results revealed that the maximum emission amounts of CO2, CH4 and N2O in the three wastewater treatment processes appeared in the aerobic areas in all cases. Theoretically, CH4 should be produced in anaerobic conditions, rather than aerobic conditions. However, results in this study showed that the CH4 emission fluxes in the forepart of the aerobic area were distinctly higher than in the anaerobic area. The situation for N2O was similar to that of CH4： the N2O emission flux in the aerobic area was also higher than that in the anoxic area. Through analysis of the GHG mass balance, it was found that the flow of dissolved GHG in the wastewater treatment processes and aerators may be the main reason for this phenomenon. Based on the monitoring and calculation results, GHG emission factors for the three wastewater treatment processes were determined. The A^2O process had the highest CO2 emission factor of 319.3 g CO2/kg CODremoved, and the highest CH4 and N2O emission factors of 3.3 g CH4/kg CODremoved and 3.6 g N2O/kg TNremoved were observed in the Orbal oxidation ditch process.
基金supported by the National Key Research and Development Program of China(No.2016YFC0801406)the National Natural Science Foundation of China(No.51674252)+4 种基金the Visitor Foundation of State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University)(No.2011DA105287-FW201405)the Qing Lan Projectthe Sponsorship of Jiangsu Overseas Research&Training Program for University Prominent Young&Middle-Aged Teachers and Presidentsthe Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities of China(No.106112015CDJXY240001)
文摘Multiple coal seams widely develop in the deep Chinese coal-bearing strata. Ground in situ stress and coal seam gas pressure increase continuously with the increase of the mining depth, and coal and gas outburst disasters become increasingly severe. When the coal is very deep, the gas content and pressure will elevate and thus coal seams tends to outburst-prone seams. The safety and economics of exploited firstmined coal seams are tremendously restricted. Meanwhile, the multiple seams occurrence conditions resulted in different methane pressure systems in the coal-bearing strata, which made the reservoir reconstruction of coal difficult. Given the characteristics of low saturation, low permeability, strong anisotropy and soft coal of Chinese coal seams, a single hydraulic fracturing surface well for reservoir reconstruction to pre-drain the coalbed methane(CBM) of multiple seams concurrently under the different gas pressure systems has not yet gained any breakthroughs. Based on analyses of the main features of deep CBM reservoirs in China, current gas control methods and the existing challenges in deep and multiple seams, we proposed a new technology for deep CBM reservoir reconstruction to realize simultaneous high-efficiency coal mining and gas extraction. In particular, we determined the first-mined seam according to the principles of effectiveness and economics, and used hydraulic fracturing surface well to reconstruct the first-mined seam which enlarges the selection range of the first-mined seam. During the process of mining first-mined seam, adjacent coal seams could be reconstructed under the mining effect which promoted high-efficiency pressure relief gas extraction by using spatial and comprehensive gas drainage methods(combination of underground and ground CBM extraction methods). A typical integrated reservoir reconstruction technology, ‘‘One well for triple use", was detailed introduced and successfully applied in the Luling coal mine. The application showed that the proposed technology could effectively promote coal mining safety and simultaneously high-efficiency gas extraction.
基金financially supported by the National Natural Science Foundation of China (Nos. 51004060, 51104074, and 51174105)the Natural Science Foundation of Yunnan Province (No. 2010ZC018)
文摘A series of Fe2O3/Al2O3, Fe2O3/CeO2, Ce0.7Zr0.3O2, and Fe2O3/Ce1-xZrxO2（x = 0.1–0.4） oxides was prepared and their physicochemical features were investigated by X-ray diffraction（XRD）, transmission electron microscope（TEM）, and H2-temperature-programmed reduction（H2-TPR） techniques. The gas–solid reactions between these oxides and methane for syngas generation as well as the catalytic performance for selective oxidation of carbon deposition in O2-enriched atmosphere were investigated in detail. The results show that the samples with the presence of Fe2O3show much higher activity for methane oxidation compared with the Ce0.7Zr0.3O2solid solution,while the CeO2-contained samples represent higher CO selectively in methane oxidation than the Fe2O3/Al2O3sample. This suggests that the iron species should be the active sites for methane activation, and the cerium oxides provide the oxygen source for the selective oxidation of the activated methane to syngas during the reaction between methane and Fe2O3/Ce0.7Zr0.3O2. For the oxidation process of the carbon deposition, the CeO2-containing samples show much higher CO selectivity than the Fe2O3/Al2O3sample, which indicates that the cerium species should play a very important role in catalyzing the carbon selective oxidation to CO. The presence of the Ce–Zr–O solid solution could induce the growth direction of the carbonfilament, resulting in a loose contact between the carbon filament and the catalyst. This results in abundant exposed active sites for catalyzing carbon oxidation, strongly improving the oxidation rate of the carbon deposition over this sample. In addition, the Fe2O3/Ce0.7Zr0.3O2also represents much higher selectivity（ca. 97 %） for the conversion of carbon to CO than the Fe2O3/CeO2sample, which can be attributed to the higher concentration of reduced cerium sites on this sample. The increase of the Zr content in the Fe2O3/Ce1-xZrxO2samples could improve the reactivity of the materials for methane oxidation, but it also reduces the selectivity for CO formation.
基金funded by the Australian Research Council (ARC), Healthy Waterways LtdSeqwater through an industry linkage grant (ARC Linkage project # LP100100325)
文摘Surface water methane （CH4） and nitrous oxide （N20） concentrations and fluxes were investigated in two subtropical coastal embayments （Bramble Bay and Deception Bay, which are part of the greater Moreton Bay, Australia）. Measurements were done at 23 stations in seven campaigns covering different seasons during 2010-2012. Water-air fluxes were estimated using the Thin Boundary Layer approach with a combination of wind and currents-based models for the estimation of the gas transfer velocities. The two bays were strong sources of both CH4 and N2O with no significant differences in the degree of saturation of both gases between them during all measurement campaigns. Both CH4 and N2O concentrations had strong temporal but minimal spatial variability in both bays. During the seven seasons, CH4 varied between 500% and 4000% saturation while N2O varied between 128 and 255% in the two bays. Average seasonal CH4 fluxes for the two bays varied between 0.5 ± 0.2 and 6.0 ± 1.5 mg CH4/（m^2.day） while N20 varied between 0.4 ± 0.1 and 1.6 ± 0.6 mg N2O/（m^2-day）. Weighted emissions （t CO2-e） were 63%-90% N2O dominated implying that a reduction in N2O inputs and/or nitrogen availability in the bays may significantly reduce the bays＇ greenhouse gas （GHG） budget. Emissions data for tropical and subtropical systems is still scarce. This work found subtropical bays to be significant aquatic sources of both CH4 and N2O and puts the estimated fluxes into the global context with measurements done from other climatic regions.
基金would like to express their gratitude to the Indonesian Endowment Fund for Education(LPDP)from the Ministry of Finance of the Republic of IndonesiaDirectorate of Research and Community Service(DRPM)ITS,Indonesia for their support in this research.
文摘Sawahlunto(SL-02) and Sangatta(KD-04) coals were analyzed for the presence of aliphatic hydrocarbon fraction biomarkers to assess their organic geochemistry and its implications for selecting exploration strategies for coal bed methane(CBM). Structural identification using the gas chromatography-mass spectrometry(GC-MS) method revealed the distribution of n-alkanes, isoprenoids, sesquiterpenoids,and triterpenoids. The organic matter in both coal samples originated from higher terrigenous plants, as indicated by the dominance of long-chain n-alkanes, carbon preference index(CPI) values greater than 1,low vs. high carbon preference index(LHCPI) values less than 1, terrigenous/aquatic ratio(TAR) values over 5, and the dominance of 8β(H)-homodrimane over 8β(H)-drimane. An oxic depositional environment is suggested by a Pr/Ph ratio greater than 1, the presence of hopanes(C31 and C32), and the low abundance of 8β(H)-drimane in both samples. CPI values greater than 1, OEP values greater than 1, LHCPI values less than 1, the abundance of 17a(H),21β(H)-homohopane(22S) compared with that of17a(H),21β(H)-homohopane(22R), and the presence of several unsaturated biomarkers in the KD-04sample, such as olean-12-ene, olean-18-ene, and neohop-13(18)-ene, indicate that the coal is relatively immature. A cross plot of the Pr/n-C17 ratio against the Ph/n-C18 ratio in the Hunt diagram classifies the sample as humic coal derived from higher terrigenous plants, deposited in an oxic environment, and as a type III kerogen with gas-generating potential in both the SL-02 and KD-04 coals.These biomarker data and parameters are highly relevant for methane gas miners in SL-02 coal from the Sawahlunto coal mine, West Sumatra, and KD-04 coal from the Sangatta coal mine, East Kalimantan. The CBM is estimated to have a biogenic origin.
