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Surface characterization of ashtree wood meal by inverse gas chromatography
Inverse gas chromatography (IGC) is a sensitive and convenient method to characterize surface properties and thermodynamic parameters of solid materials. Surface properties of ashtree wood meal were determined by inverse gas chromatography in this work. The dispersive component of the surface free energy and acid-base parameters of the ashtree wood meal were characterized. The dispersive component of surface free energy was within 36-39 mJ/m2, the Lewis acidic number Ka was 0.53, and the basic number Kb was 0.21, respectively. The results show that ashtree is amphoteric and predominantly acidic wood....
2020-09-15 12:28:59浏览：42
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Experimental Research of Gas Hydrate Drilling Fluids Using Polyethylene Glycol as an Inhibitor
Low temperature is the key for maintaining the wellbore stability of the gas hydrate well and for ensuring the safety in the well. In this article, the characteristics of drilling in the permafrost containing gas hydrates are analyzed initially. And later, the relative properties and the inhibitory mech anisms of the polyethylene glycol and the hydrate inhibitor of the drilling fluids ensuring drilling safety are discussed. On the basis of these, the effects of the molecular weight and the content of the polyethy lene glycol, and its interaction with the salts on the performances of the four groups of drilling fluids un der low temperature are mainly analyzed. The results of these analyses show that for the relative drilling fluid system, the 5％ content of polyethylene glycol with a molecular weight of 10 000 combined with 15％ NaCl+5％ KCl or 20％ NaCl is suitable....
2020-09-15 12:28:59浏览：63
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Methane fluxes and gas hydrates as well as seismic activity in the Okhotsk Sea
The research works of methane concentration in water column of the Okhotsk Sea from 1984 to 2005 were reviewed. And some regularities of methane distribution in water column in the North-East Sakhalin slope of the Okhotsk Sea were concluded....
2020-09-15 12:28:59浏览：82
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Origins of High H2S-bearing Natural Gas in China
Natural gas containing hydrogen sulphide (H2S) has been found in several petroliferous basins in China, such as the Sichuan Basin, Bohai Bay Basin, Ordos Basin, Tarim Basin, etc. Natural gas with higher H2S contents (H2S ＞5% mol.) is mostly distributed in both the gas reservoirs of Dukouhe, Luojiazhai, Puguang and Tieshanpo, which belong to the Triassic Feixianguan Formation in the northeastern Sichuan Basin and those of the Kongdian-Shahejie formations in the northeastern Jinxian Sag of the Jizhong Depression, Bohai Bay Basin. In the Sichuan Basin, the H2S contents of natural gas average over 9% and some can be 17 %, while those of the Bohai Bay Basin range from 40 % to 92 %, being then one of the gas reservoirs with the highest H2S contents in the world. Based on detailed observation and sample analysis results of a total 5000 m of core from over 70 wells in the above-mentioned two basins, especially sulfur isotopic analysis of gypsum,brimstone, pyrite and natural gas, also with integrated study of the geochemical characteristics of hydrocarbons, it is thought that the natural gas with high H2S contents resulted from thermochemical sulfate reduction (TSR) reactions.Among them, the natural gas in the Feixianguan Formation resulted from TSR reactions participated by hydrocarbon gas,while that in the Zhaolanzhuang of the Jinxian Sag being the product of TSR participated by crude oil. During the consumption process of hydrocarbons due to TSR, the heavy hydrocarbons were apt to react with sulfate, which accordingly resulted in the dry coefficient of natural gas increasing and the carbon isotopes becoming heavier....
2020-09-15 12:28:59浏览：44
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Natural gas generation model and its response in accumulated fluids in the Yinggehai basin
The natural gases found in the Yinggehai basin have nitrogen gas content ranging from 3.5% to 35%, and carbon dioxide content ranging from 0.1% to 93%. The nitrogen and CO2 contents show a wide variation even in the same gas field. The natural gas generation and evolution model has been established based on the relationship among the contents of nitrogen, carbon dioxide and hydrocarbon gases in the discovered gas fields, and the results of simulation experiments. The thickness of the Tertiary and Quaternary in the Yinggehai basin is over 17 km, and gas generation stages from diagenesis (microbial methane) to metamorphism have been developed. Nitrogen in this basin is organic in origin, and has been generated mainly in the catagenetic stage, roughly synchronous with hydrocarbon gases. Carbon dioxide is mainly inorganic in origin, and has been generated from high-temperature decomposition of carbonates in the metamorphic stage. The Dongfang gas field shows strong inter-reservoir compositional heterogeneities, and different gas reservoirs have recorded the products of gas generation at different stages. It has been confirmed that the complexity in natural gas composition in the Yinggehai basin is the combined results of multi-stage natural gas generation and multi-stage gas injection and accumulation....
2020-09-15 12:28:59浏览：64
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Research on Axial Trail of High-Speed Gas Painting Automizor
The non-linear dynamic model is set up of one type of high-speed painting automizor with gas supporting system. The stability of motion and dynamic response of the gas painting automizor system are studied over a relatively wide range of rotating speed by numerical analytic method, the critical velocity under working condition is found, and rotate stability and critical condition are discussed in theory. Furthermore, the range of the critical parameter of the system when Hopf bifurcation occurs and the law between axis trace and bearing clearance are acquired, too....
2020-09-15 12:28:59浏览：40
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Feasibility of Gas Drive in Fang-48 Fault Block Oil Reservoir
The Fang-48 fault block oil reservoir is an extremely low permeability reservoir, and it is difficult to produce such a reservoir by waterflooding. Laboratory analysis of reservoir oil shows that the minimum miscibility pressure for CO2 drive in Fang-48 fault block oil reservoir is 29 MPa, lower than the formation fracture pressure of 34 MPa, so the displacement mechanism is miscible drive. The threshold pressure gradient for gas injection is less than that for waterflooding, and the recovery by gas drive is higher than waterflooding. Furthermore, the threshold pressure gradient for carbon dioxide injection is smaller than that for hydrocarbon gas, and the oil recovery by carbon dioxide drive is higher than that by hydrocarbon gas displacement, so carbon dioxide drive is recommended for the development of the Fang-48 fault block oil reservoir....
2020-09-15 12:28:59浏览：57
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Numerical Simulation of Flow in Flowrate Measurement Section of Natural Gas Pipelines
The orifice-plate flowmeter and ultrasonic flowmeter are used widely for natural gas flowrate measurement, and the measurement accuracy is affected greatly by flow state. Numerical simulation was used to study the flow of natural gas in the diffusion pipe, and the length of the irregular flow induced by the diffuser or rectifier was computed. Simulation results indicated that the flow in the diffusion pipe was three-dimensional turbulent flow and the steady state flow was restored at 17 pipe-diameters downstream of the diffuser. The rectifiers equipped in the diffusion pipe showed good rectification effect, notwithstanding the induced irregular flow. Downstream the rectifier, the flow became symmetrical and uniform in a shorter length than the case without a rectifier. For the diffusion pipe equipped with plate rectifier, tube rectifier and tube-plate rectifier, the lengths at which uniformly distributed flow was restored were 12, 6 and 5 pipe-diameters downstream the rectifier respectively. On the basis of simulation results, the minimum installation length for flowmeters equipped in the diffusion pipe was determined. This provides a new method for improving natural gas measurement accuracy....
2020-09-15 12:28:59浏览：48
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Generation and accumulation of Quaternary shallow gas in eastern Qaidam Basin, NW China
This study presents an overview on the geological setting and geochemical characteristics of Pleistocene shallow gas accumulations in eastern Qaidam Basin, NW China. Five largest gas accumulations discovered in this region have a combined enclosure area of about 87 km2 and 7.9 trillion cubic feet (tcf) of proven plus controlled gas reserves. The dominance of methane ( ＞99.9% ) and the δ13C and δD values of methane ( - 68.51‰ to - 65.00‰ and - 227.55‰ to - 221.94‰, respectively) suggest that these gases are biogenic, derived from the degradation of sedimentary organic matter by methanogens under relatively low temperatures ( ＜75℃ ). A sufficient supply and adequate preservation of organic matter in the Pleistocene sediments is made possible by the lake basin's high altitude (2600 -3000 m),high water salinity ( ＞15% ) and strong stratification. The deposition and extensive lateral occurrence of shore and shallow lake sands/silts in beach sand sheets and small sand bars provided excellent reservoirs for the biogenic gas generated from adjacent rocks. Effective but dynamic gas seals were provided by such factors as intermittent vertical variations in the sediment lithologies, hydraulic trapping due to mudstone water saturation, the hydrocarbon gradient created as a result of gas generation from potential caprocks,and the presence of a regional caprock consisting of 400 - 800-m-thick mudstones and evaporites. It appears that the most favorable traps for large gas accumulations occur on structural slopes near the major gas kitchen, and the prolific gas pools are often those large gentle anticlines with little faulting complication....
2020-09-15 12:28:59浏览：64
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Synthesis, Characterization and Evaluation of Sulfur Transfer Catalysts for FCC Flue Gas
In this work, Zr-M (M=Cu, Mn, Ce) type sulfur transfer agent was prepared by impregnation method. Under the condition similar to that in the regenerator of FCC units, the inlfuence of different active metal components and their con-tents on sulfur transfer agent were investigated. Moreover, the crystalline structure of sulfur transfer agent was characterized by X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FT-IR). The result showed that the Zr-Mn sulfur transfer agent could effectively reduce the SO2 content in FCC regenerator lfue gas, featuring high SO2 adsorption capacity. The sulfur transfer agent was inactivated in 40—60 min during the test. In the course of reduction reaction, after several re-action cycles, the formation of SO2 ceased and only H2S was detected as the reduction product....
2020-09-15 12:28:59浏览：35
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Fractal Analysis of Gas Diffusion Layer in PEM Fuel Cells
The aim of this study is to show how fractal analysis can be effectively used to characterize thetexture of porous solids.The materials under study were carbon papers, the backing material of the gas diffusion layer (GDL) in Proton Exchange Membrane Fuel Cell (PEMFC).The fractal dimensions were calculated byanalyzing data from mercury porosimetry.The polytotrafluoroethylene (PTFE) treated carbon paper shows a significantly high fractal dimension value than pure sample, and the high fractal dimension signifies that the physical complexity of the pore surface is enhanced.The fractal dimension can be used as a valid parameter to monitor the textural evolution of the samples ns the treatment progresses, ns this behaves in a similar way to other textural pa rameters.The use of fractal analysis in conjunction with the results of classical characterization methods leads to abetter understanding of textural modifications in the processing of materials....
2020-09-15 12:28:59浏览：83
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Advances in gas content based on outburst control technology in Huainan, China
The sudden and violent nature of coal and gas outbursts continues to pose a serious threat to coal mine safety in China. One of the key issues is to predict the occurrence of outbursts. Current methods that are used for predicting the outbursts in China are considered to be inadequate, inappropriate or impractical in some seam conditions. In recent years, Huainan Mining Industry Group (Huainan) in China and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia have been jointly developing technology based on gas content in coal seams to predict the occurrence of outbursts in Hua-inan. Significant progresses in the technology development have been made, including the development of a more rapid and accurate system in determining gas content in coal seams, the invention of a sam-pling-while-drilling unit for fast and pointed coal sampling, and the coupling of DEM and LBM codes for advanced numerical simulation of outburst initiation and propagation. These advances are described in this paper....
2020-09-15 12:28:59浏览：74
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Similarity theory for the physical simulation of natural gas hydrate reservoir development
In order to apply physical simulation results to natural gas hydrate reservoir parameters to provide a theoretical framework for the design of a development plan,an analytical equation method was used to obtain the similarity criteria of natural gas hydrate reservoir development by physical simulation,based on a mathematical model of natural gas hydrate development.Given the approach of numerical simulation,a sensitivity analysis for all parameters was carried out,which specifically demonstrated that initial temperature is the most important parameter.Parameters of thermal conductivity coefficients are not necessary for conducting the NGH dissociation process,which will fundamentally simplify the design and establishment of the model.The analysis provides a sound theoretical basis and design principles for particular similarity....
2020-09-15 12:28:59浏览：58
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Concentration profile of jet gas in the feed injection zone of a FCC riser
The concentration profiles of jet gas are investigated in the feed injection zone of a cold-model FCC riser by using a hydrogen trace technique.Experimental results demonstrate that four types of jet gas concentration profiles can be used to describe the mixing between the jet gas and pre-lift gas in the feed injection zone.The four types are a distinct M-shaped profile for weak mixing,an indistinct Mshaped profile for medium mixing,a sharp profile for strong mixing,and a parabolic profile for full mixing.The heights for regions of initial and full mixing reduce when decreasing the jet gas velocity or increasing the pre-lift gas velocity.Furthermore,the momentum ratio,Mj/Mr,(where Mj is the momentum of jet gas,Mr is the mixture momentum of pre-lift gas and solid particles) is introduced to describe the effects of gas-solid physical properties,operating conditions,and equipment configuration on the jet gas concentration distribution.The heights for regions of initial and full mixing between jet gas and pre-lift gas are found to be 0-0.375 and 0.375-0.675 m when Mj/Mr ＜ 0.29,0.375-0.675 and 1.075-1.375 m when Mj/Mr ＞ 0.54,and 0-0.375 and 0,675--1.075 m when Mj/Mr between 0.29 and 0.54,respectively....
2020-09-15 12:28:59浏览：65
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A Study on Inhibitors for the Prevention of Hydrate Formation in Gas Transmission Pipeline
Gas Hydrate is usually formed during the transportation and treatment of oil and gas,resulting in the plugging of gas pipeline and equipment. Three thermodynanic calculation formulas are analyzed to deal with this problem. The lowering of the freezing point of the inhibitors △T is used to calculate the formation temperature of natural gas hydrates. This is. considered to be a good approach because it is not limited by what kind and what concentration of inhibitors one uses. Besides, the rate of lowering of the freezing point could be easily measured. The result of testing methanol and mono-ethylene glycol in a reactor shows that adding 10% inhibitors to the reactor can prevent the hydrates formation.Kinetic inhibitors are favored in the present research. They are divided into two types, polymer and surface-active agents. Their characteristics, mechanisms, and application prospect are separately discussed.Polymer inhibitors exhibit better efficiency. The result of field application of VC-713 inhibiter is also given in this article. In practice, the combination of thermodynamic inhibitors and kinetic inhibitors gives better result....
2020-09-13 23:35:02浏览：28
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