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<正>2000年6月,日本政府设立了"天然气水合物开发研究委员会",并制订了《日本天然气水合物开发计划》(简称《计划》)。2002年3月,"天然气水合物资源开发研究财团"成立,吸引民间企业和大学等团体的研究人员参加天然气水合物勘探开发等综合研究。《计划》以推进天然气水合物的钻探和生产回收技术的研究为目的 ,2001~2018年将致力于实现6个目标。《计划》分为3个阶段:2001~2008年,探明日本周边海域的天然气水合物赋存状况和分布特征,预测可能海域的天然气 相似文献
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天然气水合物是一种分布广泛的新型清洁能源,是目前能源勘探界的研究热点之一。提升天然气水合物勘探技术以探测天然气水合物分布和进行资源量估算,对我国天然气水合物的开采和利用至关重要。本文对比总结了似海底反射(BSR)和海洋可控源电磁法(CSEM)识别天然气水合物的优势与局限性。结果表明,BSR是目前识别海洋天然气水合物的一种常用且重要的方法,但BSR与天然气水合物的存在并非一一对应,难以准确估算天然气水合物饱和度和资源量。海洋CSEM能相对准确地识别天然气水合物,并可通过获取储层电阻率估算天然气水合物饱和度和储量。两者的结合将有效提高天然气水合物的钻探成功率、降低勘探风险和节约勘探成本。 相似文献
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海域天然气水合物的聚集和分布呈现出明显的不均匀性。本文运用“天然气水合物油气系统”的理论和方法,从墨西哥湾、布莱克海台、水合物脊、南海海槽等国际典型水合物赋存区的稳定条件、气体组分和来源、流体运移、沉积条件四个方面解剖各区水合物的成藏控制因素。通过分析和对比认识到水合物赋存区的范围相对较小,海底温度和压力可视为均一条件,热成因气和生物成因气均可作为水合物的气体来源,同一个区域内的气体组分相对稳定,但有利沉积体和为含气流体运移提供通道的运移条件,也即“天然气水合物运聚体系”是控制水合物分布的关键因素。南海北部陆坡神狐海域水合物储集于颗粒相对较粗、孔隙空间相对较大沉积体中,而下部的气烟囱和断层构成了神狐海域的含气流体运移通道,这种有利的运聚体系有机结合可能是天然气水合物富集的关键因素。因此,针对水合物储集体的精细沉积学解释和流体运移通道的解剖,可能是南海北部陆坡天然气水合物勘探中需要引起重视的一个方向。 相似文献
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<正>2010年3月21日从青海省科技厅获悉,有关专家对中国科学院广州天然气水合物研究中心先期完成的《青海省天然气水合物勘探开发方案研究报告》进行了审查,指出青海省多年冻土区具备较好的天然气水合物找矿前景,并建议在青海建立一个陆地勘探开发技术方法试验基地,对我国天然气水合物勘探开发起到带动作用。天然气水合物是一种清洁能源,被誉为"后石油时代"最有希望的战略资源。有关研究资料显示,中国陆域天然气水合物主要存于青藏高原冻土带,专 相似文献
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《中外能源》2015,(4)
全球天然气水合物资源丰富,分布广泛,将在未来能源发展战略中占有重要地位。作为天然气水合物勘探开发的关键环节,测井技术不仅可为水合物地层识别和参数评价提供高分辨率、连续的数据资料,还有助于提高勘探效率,降低钻井风险。对全球天然气水合物研究进展和测井历程进行了调研,论述了电缆测井与随钻测井方法的主要作用和应用效果,得出随钻测井在准确评价天然气水合物分布情况方面具有明显优势,同时,利用电缆测井可对随钻测井数据进行校正,进而进一步提高测井作业的准确度和可靠性。结合日本Nankai海槽水合物项目、美国水合物海岭Hydrate Ridge的海洋钻探项目ODP 204航次及墨西哥湾的联合工业项目JIP等测井作业实例,系统分析了国外水合物测井整体概况,指出国外天然气水合物测井技术大多采用电缆测井与随钻测井相结合的模式。我国天然气水合物研究工作起步较晚,目前主要的水合物分布区包括南海北部陆坡的神狐海域及青海祁连山南缘的永久冻土带等,随钻测井主要依靠国外公司提供的相关技术,未来可在借鉴国外经验的基础上,加强天然气水合物测井基础理论、高新技术、仪器装备等方面的研究。 相似文献
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西南巴伦支海是挪威北极圈的一部分,具备天然气水合物富集成藏的有利地质条件,且存在明显的天然气水合物识别标志。本文收集和整理了巴伦支海西南地区与天然气水合物相关的资料,发现BSR、空白反射带和浅部气体聚集异常反射等地球物理标志主要在Loppa高地西部和Hammerfest盆地西部广泛分布;麻坑、气烟囱、断裂及其他气体渗漏构造地质标志主要在Asterias复合断裂带附近和Hammerfest盆地西部密集分布。因此,西南巴伦支海天然气水合物的有利勘探目标区主要是Loppa高地西部和Hammerfest盆地西部。结合区域地质背景分析上述各种识别标志的平面分布特征,推断该区天然气水合物的富集成藏与有效的含气流体运移通道密切相关。 相似文献
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Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden. 相似文献
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《热能动力工程》2014,(5)
正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%. 相似文献
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The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°, −5°, +5°, +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods. 相似文献
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A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified. 相似文献
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The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σred = σ1 β + (1 − β)σi, where: σ1-maximal principal stress, σi-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures. 相似文献
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Jaime Massanet-Nicolau Alan Guwy Richard Dinsdale Giuliano Premier Sandra Esteves 《International Journal of Hydrogen Energy》2010
Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H2 kg−1 VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min−1 successfully prevented a decline in hydrogen production and resulted in a yield of 27.0 L H2 kg−1 VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production. 相似文献
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As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied. 相似文献