卡罗里纳陆隆富含甲烷羽流与气水化合物的关系

卡罗里纳陆隆富含甲烷羽流与气水化合物的关系ＣｈａｒｌｅｓＫ．Ｐａｕｌｌ等气水化合物是由水和低分子量气体在低温、高压及气体浓度足够高的条件下形成的结晶固体。尽管推测气水化合物是构成地球上ＣＨ＿４贮量的主要部分，目前关于气体和流体穿透含气水化合物沉积层的...

Hydrated coefficient of clathrates and its applications in determination of aqueous inclusions with multivolatile components

During the microthermometric measurement（cooling）of aqueous inclusions with multivolatile components,solid crystals of gas clathrates often occur with snow-flower-or soft-ice appearances.The structural formula of these solids is M·nH2O（where n≥5.67）.Many hydrocarbons,related compounds and their binary or multi-component mixtures may generate gas clathrates.This phenomenum is of fundamental importance to the study of inclusions with hydrocarbon aqueous solutions,because this is related to the determination of inclusion parameters and the computation of thermodynamic parameters. In the nature most aqueous inclusions contain not merely one volatile component but multi-volatile components.Therefore,the measurement of aqueous inclusions with multivolatile components is of universal significance and great importance.There have been many studies and available formula or figures about the computation of thermodynamic parameters for aqueous inclusions with one volatile component.Nevertheless,there are few studies concerning with muhivolatile components and it is very difficult to computate thermodynamic parameters for aqueous inclusions with these components. In this paper,hydrated coefficient K is introduced.Ki is the ratio of molar fraction of component i in the gas phase to that in the gas clathrate,or Ki=yi/xi.Because K is a function of temperatures and pressures,it can be used to evaluate the temperature-pressure conditions on the phase behavior with muhivolatile components. Based on the regression analysis of available experimental data,the authors have developed computational expression of hydrated coefficients in relation to temperature and pressure for most hydrocarbons and other volatile components,which is helpful to conveniently compute thermodynamic parameters on stability state for elathrates with volatile components.As aqueous inclusions with muhivolatile components are common in the nature,by the use of final melting temperatures of clathrates from mierothermometry and these formula,fluid density of gas phase with valotile components and bulk fluid density of inclusions can be accurately calculated. Furthermore,this method may provide foundations to determine the isochores of inclusions and to calculate trapping temperatures and pressures. Finally,detailed analyses for two computational examples about aqueous inclusions with muhivolatile components are presented.

Effects of salinity and body mass on oxygen consumption and ammonia excretion of mudskipper Boleophthalmus pectinirostris

We evaluated the effects of salinity and body mass on the oxygen consumption rate and ammonia excretion rate of mudskipper Boleophthalmus pectinirostris under laboratory conditions. Salinity and body mass had highly significant effects on the oxygen consumption rate （Ro） and ammonia excretion rate （RN） （P〈0.01）. The interactive effects between salinity and body mass on Ro and RN were insignificant （P〉0.05） and highly significant （P〈0.01）, respectively. Ro and RN of B. pectinirostris decreased significantly as the individual body mass increased. The relationship between Ro and body mass was represented by Ro=aWb （R^2=0.956, P〈0.01）. The relationship between RN and the body mass ofB. pectinirostris was represented by RN-cW^at （R^2=0.966, P〈0.01）. The Ro/RN （O：N） ratios increased significantly as the salinity increased from 12 to 27, but decreased as salinity increased from 27 to 32. The atomic O：N ratios were significantly higher at 27 than at other salinity levels. The average O：N ratio was 25.25. Lipid and carbohydrate were the primary energy sources and protein was the secondary energy significantly higher at 27 than at other salinity levels B, pectinirostris is 27. source within the salinity range 12 32. Ro andRN were Our results suggest that the optimum salinity level for B. pectinirostris is 27.

Catalytic Transformation of Oxygenated Organic Compounds into Pure Hydrogen

The continual growth in transportation fuels and more strict environmental legislations have led to immense interest in developing green biomass energy. In this work, a proposed catalytic transformation of oxygenated organic compounds （related to bio-oil） into pure hydrogen was desighed, involving the catalytic reforming of oxygenated organic compounds to hydrogen- rich mixture gas followed by the conversion of CO to CO2 via the water gas reaction and the removal of CO2. The optimization of the different reforming catalyst, the reaction conditions as well as various sources of oxygenated organic compounds were investigated in detail. The production of pure hydrogen, with the H2 content up to 99.96% and the conversion of 97.1%, was achieved by the integrated catalytic transformation. The reaction pathways were addressed based on the investigation of decomposition, catalytic reforming, and the water gas reaction.

Recovery of Hydrogen from Ammonia Plant Tail Gas by Absorption-Hydration Hybrid Method

In this work, the absorption-hydration hybrid method was used to recover （hydrogen ＋ nitrogen） from （hydrogen ＋ nitrogen ＋ methane ＋ argon） tail gas mixtures of synthetic ammonia plant through hydrate formation/dissociation. A high-pressure reactor with magnetic stirrer was used to study the separation efficiency. The in-fluences of the concentration of anti-agglomerant, temperature, pressure, initial gas-liquid volume ratio, and oil-water volume ratio on the separation efficiency were systematically investigated in the presence of tetrahydro-furan （THF）. Anti-agglomerant was used to disperse hydrate particles into the condensate phase for water-in-oil emulsion system. Since nitrogen is the material for ammonia production, the objective production in our separation process is （hydrogen ＋ nitrogen）. Our experimental results show that by adopting appropriate operating conditions, high concentration of （hydrogen ＋ nitrogen） can be obtained using the proposed technology based on forming hydrate.

Pulsed Corona Discharges and Their Applications in Toxic VOCs Abatement

Plasma processes are among the emerging technologies for volatile organic compounds (VOCs) abatement[1]. Both thermal plasmas and non-equilibrium plasmas (cold plasmas) are being developed for VOCs cleanup[2,3]. Particularly, pulsed corona discharges offer several advantages over conventional VOCs abatement techniques[4-7]. To optimize the existing technology and to develop it further, there is need to understand the mechanisms involved in plasma chemical reactions. Furthermore, it is strongly desirable to be able to predict the behavior of new VOCs in non-equilibrium plasma environment from the data known for a few representative compounds. Pulsed corona discharge technique is introduced here with citation of relevant literature. Fundamental principles, useful for predicting the VOCs' decomposition behavior, have been worked out from the published literature. Latest developments in the area, targeted to minimize the energy losses, improve the VOCs destruction efficiency and reduce the generation of unwanted organic and inorganic by-products, are presented.

Experimental Study of Natural Gas Storage in Hydrates

Hydrate formation rate plays an important role in the making of hydrates for natural gas storage. The effect of sodium dodecyl sulfate (SDS), alkyl polysaccharide glycoside (APG) and cyclopentane (CP) on natural gas hydrate formation rate, induction time and storage capacity was studied. Micellar surfactant solutions were found to increase hydrate formation rate in a quiescent system and improve hydrate formation rate and natural gas storage capacity. The process of hydrate formation includes two stages with surfactant presence. Hydrate forms quickly in the first stage, and then the formation rate is slowed down. Surfactants (SDS or APG) reduce the induction time of hydrate formation. The effect of an anionic surfactant (SDS) on gas storage in hydrates is more pronounced compared to a nonionic surfactant (APG). CP also reduces the induction time of hydrate formation, but can not improve the natural gas storage capacity in hydrates.

Carbon Dioxide Capture Using Gas Hydrate Technology

According to IPCC （Intergovemmental Panel on Climate Change） Fourth Report, carbon dioxide emissions from the combustion of fossil fuels have been identified as the major contributor to global warming and climate change. One of the new approaches for capturing carbon dioxide and subsequently lowering the emissions is based on gas hydrate crystallization. Gas hydrates have a large capacity for the storage of gases which also resemble an attractive method for gas filtration. The basis of the separation is the selective partition of the target component between the hydrate phase and the gaseous phase. It is expected that carbon dioxide is preferentially encaged into the hydrate crystal phase compared to the other components. In the present paper, after a comparison of gas hydrates with existing capture technologies, a novel apparatus for gas hydrate production is illustrated and results of a first set of experimental applications of the reactor for CO2 hydrate formation and separation are presented. In particular, the effects of two different promoters were investigated. Results show that the reactor allows a good level of temperature control, resulting in rapid hydrate formation and mild operating conditions. Results are a basis for setting up a procedure for CO2 separation and capture.

Physical Simulation of Water Dissolved Gas (WDG)During Migration

By using the equipment designed and developed by ourselves, experiment of investigating the influence of dissolution on some geo-chemical parameters (such as δ13C,δD,and iC4/nC4 in water-dissolved gas (WDG) during migration) was performed. The result shows that, with the increase of distance, 1) the relative abundance of non-hydrocarbon (CO2) and hydrocarbon (CH4) increase while the relative abundance of hydrocarbon (C2+) decreases (the relative abundance of hydrocarbon (C5+) can be basically negligible); 2) the relative abundance of benzene and methylbenzene increase in the initial time and then decrease. The carbon and hydrogen isotopes of methane vary slightly, which can be regarded as indicators of gas dissolved in water formation.

Variations of pore water sulfate gradients in sediments as indicator for underlying gas hydrate in Shenhu Area, the South China Sea

Shenhu Area is one of the most promising areas for gas hydrate exploration in the northern South China Sea （SCS）. Pore water sulfate gradient, sulfate-methane interface （SMI） depth, and sulfate flux were analyzed at 53 sites in this area. SO42- gradient ranges between 0.33 and 4.43 mmol L-L m-1. SMI depths are from 7.7 to 87.9 mbsf. Sulfate flux varies between 2.0 and 26.9 mmol m-2 yr L, with a mean of 11.7 mmol m-2 yr1. Correlation coefficient between SMI depth and methane flux for the 53 sites is -0.80, implying that methane flux regulates the rate of anaerobic methane oxidation （AMO）, SMI depth, and sulfate flux. Twelve anomalous fields with high methane flux and steep sulfate gradients were recognized. Bottom simulating reflector （BSR） is distributed mainly in areas where SMI depth is less than 50 mbsf or places with sulfate flux larger than 3.5 mmol m-2 yr-1. It is suggested that the Baiyun Sag and the Southern Uplift are potential areas for gas hydrate exploration.

Geochemistry and genesis of authigenic pyrite from gas hydrate accumulation system in the Qilian Mountain permafrost, Qinghai, northwest China

A type of authigenic pyrites that fully fill or semi-fill the rock fractures of drillholes with gas hydrate anomalies are found in the Qilian Mountain permafrost; this type of pyrite is known as ＂fracture-filling＂ pyrite. The occurrence of ＂fracture-filling＂ pyrite has a certain similarity with that of the hydrate found in this region, and the pyrite is generally concentrated in the lower part of the hydrate layer or the hydrate anomaly layer. The morphology, trace elements, rare earth elements, and sulfur isotope analyses of samples from drillhole DK-6 indicate that the ＂fracture-filling＂ pyrites are dominated by cubic ones mainly aligned in a step-like fashion along the surfaces of rock fractures and are associated with a circular structure, lower Co/Ni and Sr/Ba, lower ZREE, higher LREE, significant Eu negative anomalies, and 634ScDT positive bias. In terms of the pyrites＇ unique crys- tal morphology and geochemical characteristics and their relationship with the hydrate layers or abnormal layers, they are closely related with the accumulation system of the gas hydrate in the Qilian Mountain permafrost. As climate change is an important factor in affecting the stability of the gas hydrate, formation of fracture-filling pyrites is most likely closely related to the secondary change of the metastable gas hydrate under the regional climate warming. The distribution intensity of these py- rites indicates that when the gas hydrate stability zone （GHSZ） is narrowing, the hydrate decomposition at the bottom of the GHSZ is stronger than that at the top of the GHSZ, whereas the hydrate decomposition within the GHSZ is relatively weak. Thus, the zone between the shallowest and the deepest distribution of the fracture-filling pyrite recorded the largest possible original GHSZ.

Molecular dynamics simulations of the mechanisms of thermal conduction in methane hydrates

The thermal conductivity of methane hydrate is an important physical parameter affecting the processes of methane hydrate exploration,mining,gas hydrate storage and transportation as well as other applications.Equilibrium molecular dynamics simulations and the Green-Kubo method have been employed for systems from fully occupied to vacant occupied sI methane hydrate in order to estimate their thermal conductivity.The estimations were carried out at temperatures from 203.15 to 263.15 K and at pressures from 3 to 100 MPa.Potential models selected for water were TIP4P,TIP4P-Ew,TIP4P/2005,TIP4P-FQ and TIP4P/Ice.The effects of varying the ratio of the host and guest molecules and the external thermobaric conditions on the thermal conductivity of methane hydrate were studied.The results indicated that the thermal conductivity of methane hydrate is essentially determined by the cage framework which constitutes the hydrate lattice and the cage framework has only slightly higher thermal conductivity in the presence of the guest molecules.Inclusion of more guest molecules in the cage improves the thermal conductivity of methane hydrate.It is also revealed that the thermal conductivity of the sI hydrate shows a similar variation with temperature.Pressure also has an effect on the thermal conductivity,particularly at higher pressures.As the pressure increases,slightly higher thermal conductivities result.Changes in density have little impact on the thermal conductivity of methane hydrate.