共查询到20条相似文献，搜索用时 31 毫秒
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Arumugam Sakunthalai Ramadhas Chandrasekaran Muraleedharan Simon Jayaraj 《洁净——土壤、空气、水》2008,36(12):978-983
Biodiesel is a renewable alternative fuel that can be used as substitute for mineral diesel. The use of biodiesel in diesel engines reduces all of the exhaust emissions expect NOx. The higher temperature in the combustion chamber increases the NOx emissions. The recirculation of a small percentage of cooled exhaust gases into the combustion chamber through the intake manifold reduces the in‐cylinder temperature. Moreover, the cooling of exhaust gases before mixing with fresh air introduced to the engine does not affect its volumetric efficiency but it absorbs the heat of combustion. This leads to a reduction in NOx emissions and improves the engine brake thermal efficiency. This paper describes the investigation of the performance and emission characteristics of a biodiesel‐fueled, naturally aspirated, single cylinder diesel engine with cooled exhaust gas recirculation. 相似文献
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Analytical Solutions for Gas Flow Due to Gas Injection and Extraction from Horizontal Wells 总被引：2，自引：0，他引：2
Ronald W. Falta 《Ground water》1995,33(2):235-246
Analytical solutions are developed for modeling the transient and steady-state gas pressure and the steady-state streamfunction fields resulting from gas injection and extraction from a pair of parallel horizontal wells. These solutions apply to cases in which the ground surface is open to the atmosphere, and in which the porous media is anisotropic but homogeneous. By neglecting end effects due to the finite length of the wells, the three-dimensional gas flow field is approximated as a two-dimensional cross section perpendicular to the wells. These solutions may be used to develop estimates of the horizontal well system behavior and to analyze horizontal well gas pump tests, and are useful for numerical model verification. 相似文献
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Active faults are commonly associated with spatially anomalously high concentrations of soil gases such as carbon dioxide
and Rn, suggesting that they are crustal discontinuities with a relatively high vertical permeability through which crustal
and subcrustal gases may preferably escape towards the earth's surface. Many earthquake-related hydrologic and geochemical
temporal changes have been recorded, mostly along active faults especially at fault intersections, since the 1960s. The reality
of such changes is gradually ascertained and their features well delineated and fairly understood. Some coseismic changes
recorded in ``near field' are rather consistent with poroelastic dislocation models of earthquake sources, whereas others
are attributable to near-surface permeability enhancement. In addition, coseismic (and postseismic) changes were recorded
for many moderate to large earthquakes at certain relatively few ``sensitive sites' at epicentral distances too large (larger
for larger earthquakes, up to 1000 km or more for magnitude 8) to be explained by the poroelastic models. They are probably
triggered by seismic shaking. The sensitivity of different sites can be greatly different, even when separated only by meters.
The sensitive sites are usually located on or near active faults, especially their intersections and bends, and characterized
by some near-critical hydrologic or geochemical condition (e.g., permeability that can be greatly increased by a relatively
small seismic shaking or stress increase). Coseismic changes recorded for different earthquakes at a sensitive site are usually
similar, regardless of the earthquakes' location and focal mechanism. The sensitivity of a sensitive site may change with
time. Also pre-earthquake changes were observed hours to years before some destructive earthquakes at certain sensitive sites,
some at large epicentral distances, although these changes are relatively few and less certain. Both long-distance coseismic
and preseismic changes call for more realistic models than simple elastic dislocation for explanation. Such models should
take into consideration the heterogeneity of the crust where stress is concentrated at certain weak points (sensitive sites)
along active faults such that the stress condition is near a critical level prior to the occurrence of the corresponding earthquakes.
To explain the preseismic changes, the models should also assume a broad-scaled episodically increasing strain field. 相似文献
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使用SP3400气相色谱仪对腾冲大滚锅溢出气体进行气相色谱测定,发现在不同条件下一些气体组分含量有明显变化。为获得准确可靠的观测结果,对可能影响观测结果的各个环节进行实验。实验结果显示:铝箔气体样品袋对硫化物吸附较大,取样前用气样对气袋反复冲洗3次以上可以解决此问题;气样取回后放入冰箱冷冻20～30min能很好解决样品中水汽对仪器的影响;气体样品袋注入不同体积气体对测值基本没有影响;常规组分中H2、CO2、CH4稳定性很好,10天内测试最大相对误差在10%以内;O2组分在测试中偶然变化较大,无明显规律。 相似文献
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Many basaltic volcanoes emit a substantial amount of gas over long periods of time while erupting relatively little degassed lava, implying that gas segregation must have occurred in the magmatic system. The geometry and degree of connectivity of the plumbing system of a volcano control the movement of magma in that system and could therefore provide an important control on gas segregation in basaltic magmas. We investigate gas segregation by means of analogue experiments and analytical modelling in a simple geometry consisting of a vertical conduit connected to a horizontal intrusion. In the experiments, degassing is simulated by electrolysis, producing micrometric bubbles in viscous mixtures of water and golden syrup. The presence of exsolved bubbles induces a buoyancy-driven exchange flow between the conduit and the intrusion that leads to gas segregation. Bubbles segregate from the fluid by rising and accumulating as foam at the top of the intrusion, coupled with the accumulation of denser degassed fluid at the base of the intrusion. Steady-state influx of bubbly fluid from the conduit into the intrusion is balanced by outward flux of lighter foam and denser degassed fluid. The length and time scales of this gas segregation are controlled by the rise of bubbles in the horizontal intrusion. Comparison of the gas segregation time scale with that of the cooling and solidification of the intrusion suggests that gas segregation is more efficient in sills (intrusions in a horizontal plane with typical width:length aspect ratio 1:100) than in horizontally-propagating dykes (intrusions in a vertical plane with typical aspect ratio 1:1000), and that this process could be efficient in intermediate as well as basaltic magmas. Our investigation shows that non-vertical elements of the plumbing systems act as strong gas segregators. Gas segregation has also implications for the generation of gas-rich and gas-poor magmas at persistently active basaltic volcanoes. For low magma supply rates, very efficient gas segregation is expected, which induces episodic degassing activity that erupts relatively gas-poor magmas. For higher magma supply rates, gas segregation is expected to be less effective, which leads to stronger explosions that erupt gas-rich as well as gas-poor magmas. These general physical principles can be applied to Stromboli volcano and are shown to be consistent with independent field data. Gas segregation at Stromboli is thought likely to occur in a shallow reservoir of sill-like geometry at 3.5 km depth with exsolved gas bubbles 0.1–1 mm in diameter. Transition between eruptions of gas-poor, high crystallinity magmas and violent explosions that erupt gas-rich, low crystallinity magmas are calculated to occur at a critical magma supply rate of 0.1–1 m3 s− 1. 相似文献
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地震前兆观测是地震预报的基础。地震流体前兆观测在水资源过度开采的形势下,发展断层土壤气观测成为必然趋势。但地下流体观测技术规范未给出断层土壤气观测的集气-采气装置及采气条件的具体参数,而这些参数正是影响观测结果的重要因素。因此,本文对断层土壤气气氡观测的采气条件进行了实验研究及分析。结果表明,当日采气量一定时,集气室体积的大小对观测结果有较大影响。运用"采气率"这个概念来定量衡量断层土壤气观测装置系统的实用效果。集气室有效体积的大小应根据日采气量的多少来确定,采气量越大,集气室有效体积应越大,结合地震前兆观测实际,采气率应接近于1。本文实验研究结果对规范断层土壤气气氡观测提供了科学依据,也可供其它气体观测参考。 相似文献
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In the exploration of the hidden Haihe fault, radon and mercury in soil gas were measured by using FG-3017 radon detector and XG-4 mercury analyzer. In this paper, based on the measurement results of 12 fault gas profiles, and integrating with the exploration results of artificial seismic prospecting, the relationship between anomalous site of fault gas and fault location is analyzed. Using the relationship between anomalous strength of fault gas and fault activity, the activity of Haihe fault is studied, thus the location and activity segmentation of the Haihe fault in Tianjin region are presented. This study shows that the method of fault gas detection can not only identify the preliminary location of fault, but also make preliminary segmentation of fault activity. The fault detected by the method of fault gas measurement is shown as a band. Through contrasting with exploration results of artificial seismic prospecting and analyzing, we find that the fault is located inside the band. According to the measurements of soil gas radon, the Haihe fault can be divided into east and west segments and the activity of the east segment of Haihe fault is stronger than that of the west segment. This is only a relative result, and it is difficult to judge whether the fault is active or not with this result. 相似文献
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通过气体放置时间对观测结果影响的实验，得出气体放置时间对气体He、H2、O2、N2组分含量影响较小，而CO2组分含量随时间而衰减，其速度愈来愈慢的结论。 相似文献
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提出了直接找渍气的必要性和可能性,回顾了以往失误的原因,推荐了百灵软件,并期望各石油公司经理层能使用该软件,化较小的代价对地震资料进一步解释利用而提高钻井成功率,并最终降低油气成本。 相似文献
15.
Diisopropanolamine Biodegradation Potential at Sour Gas Plants 总被引：1，自引：0，他引：1
Lisa M. Gieg E. Anne Greene Debora L. Coy Phillip M. Fedorak 《Ground Water Monitoring & Remediation》1998,18(3):158-173
The potential for aerobic and anaerobic biodegradation of a sour gas treatment chemical, diisopropanolamine (DIPA), was studied using contaminated aquifer materials from three sour gas treatment sites in western Canada. DIPA was found to be readily consumed under aerobic conditions at 8°C and 28°C in shake flask cultures incubated with aquifer material from each of the sites, and this removal was characterized by first-order kinetics. In addition, DIPA biodegradation was found to occur under nitrate-, Min(IV)., and Fe(III)-reducing conditions at 28°C, and in some cases at 8°C, in laboratory microcosms, DIPA loss corresponded to consumption of nitrate, and production of Mn(II) and Fe(II) in viable microcosms compared to corresponding sterile controls. A threshold DIPA concentration near 40 mg/L was observed in the anaerobic microcosms. This report provides the first evidence that DIPA is biodegraded under anaerobic conditions, and our data suggest that biodegradation may contribute to DIPA attenuation under aerobic and anaerobic conditions in aquifers contaminated with this sour gas treatment chemical. 相似文献
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Hale Ozgun Mustafa Evren Ersahin Selime Erdem Burcu Atay Sema Sayili Esra Eren Pelin Hoshan Doga Atay Mahmut Altinbas Cumali Kinaci Ismail Koyuncu 《洁净——土壤、空气、水》2013,41(12):1175-1182
A reliable wastewater characterization is a prerequisite for the selection of an acceptable treatment strategy for produced water which exhibits significant differences due to the varied kinds of wells, seasonal changes, and formation types. A complete characterization of produced water generated from oil, gas, and oil–gas fields in Turkey was performed based on seasonal and locational variations. The results showed that the produced water generated from oil field wells was highly polluted and wastewater volume was higher in comparison to gas and oil–gas field wells. Besides, the characterization of produced water was varying in a wide range based on seasonal and locational variations. Useful relationships were observed between chloride, sodium, bromide, and total dissolved solids concentrations. The results can be used in the design, operation, and optimization of wastewater treatment systems of petroleum and oil industries for future studies. 相似文献
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A Model for Deepwater Oil/Gas Blowouts 总被引：1，自引：0，他引：1
When gas is released in deepwater, the high pressure and low temperature can convert the gases into hydrates, which are buoyant. As these hydrates travel upwards they will encounter regions of lower pressure and can decompose into free gas. The presence or absence of hydrates has a significant impact on the behaviour of the jet/plume due to the alteration of the buoyancy. The free gas may dissolve in water. This paper describes a computer model developed to simulate the behaviour of oil and gas released from deepwater locations in the ocean. The model integrates the hydrodynamics and thermodynamics of the jet/plume with kinetics and thermodynamics of hydrate formation/decomposition. Model formulation and comparison of results with laboratory data for hydrates is presented. Scenario simulations show the behaviour of oil/gas under different deepwater conditions. 相似文献
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The soil 222Rn concentration non-linear patterns are investigated by the application of various chaos methodologies based on 70 272 measurement data from the East Anatolian Fault Zone, which is one of the world’s most active faults. Among these methodologies are Lyapunov exponent, surrogate data, rescaled range (R/S) analysis, Fourier spectrum, phase space reconstruction, mutual information, false nearest neighbors, and correlation dimension. The results indicate that the nonlinear dynamical approach is convenient for characterization and prediction of the 222Rn concentration dynamics, which are in turn usually used as an earthquake precursor. Behaviour of 222Rn gas is important in earthquake prediction researches. 相似文献