排序方式： 共有44条查询结果，搜索用时 31 毫秒
1.
Zhang Guanglei Ranjith P. G. Perera M. S. A. Lu Yiyu Choi Xavier 《Natural Resources Research》2019,28(4):1639-1660
Natural Resources Research - High-volatile bituminous coal samples were reacted in deionized water with supercritical CO2 (ScCO2–water) under simulated in situ pressure and temperature... 相似文献
2.
A review of coal properties pertinent to carbon dioxide sequestration in coal seams: with special reference to Victorian brown coals 总被引：2，自引：1，他引：1
M. S. A. Perera P. G. Ranjith S. K. Choi A. Bouazza J. Kodikara D. Airey 《Environmental Earth Sciences》2011,64(1):223-235
This paper presents reviews of studies on properties of coal pertinent to carbon dioxide (CO2) sequestration in coal with specific reference to Victorian brown coals. The coal basins in Victoria, Australia have been
identified as one of the largest brown coal resources in the world and so far few studies have been conducted on CO2 sequestration in this particular type of coals. The feasibility of CO2 sequestration depends on three main factors: (1) coal mass properties (chemical, physical and microscopic properties), (2)
seam permeability, and (3) gas sorption properties of the coal. Firstly, the coal mass properties of Victorian brown coal
are presented, and then the general variations of the coal mass properties with rank, for all types of coal, are discussed.
Subsequently, coal gas permeability and gas sorption are considered, and the physical factors which affect them are examined.
In addition, existing models for coal gas permeability and gas sorption in coal are reviewed and the possibilities of further
development of these models are discussed. According to the previous studies, coal mass properties and permeability and gas
sorption characteristics of coals are different for different ranks: lignite to medium volatile bituminous coals and medium
volatile bituminous to anthracite coals. This is important for the development of mathematical models for gas permeability
and sorption behavior. Furthermore, the models have to take into account volume effect which can be significant under high
pressure and temperature conditions. Also, the viscosity and density of supercritical CO2 close to the critical point can undergo large and rapid changes. To date, few studies have been conducted on CO2 sequestration in Victorian brown coal, and for all types of coal, very few studies have been conducted on CO2 sequestration under high pressure and temperature conditions. 相似文献
3.
4.
5.
World energy resources are depleting at an alarming rate, and natural gas has been identified as an environmentally friendly energy resource, with shale gas being one option. However, the extremely low permeability of shale plays has caused them to fail to produce a commercially viable amount of gas. Therefore, appropriate production enhancement techniques, including hydro-fracturing, are required. This paper reviews the research on shale gas production enhancement using foam-based hydro-fracturing and focuses on research on shale deposit distribution around the world, the importance of shale gas recovery, major shale gas recovery enhancement techniques, the effectiveness of foam-based fracturing depending on the foam type used and the formation properties, advantages and limitations of foam-based fracturing compared to other fluids, and existing experimental and numerical studies and field studies. According to the available experimental and modelling studies on foam fracturing, N2-based foams are stronger than CO2-based foams. The effective viscosity that controls the foam rheology decreases with increasing temperature and decreasing pressure and foam quality, and fracture length reduces and fracture width increases with increasing foam quality. Although this technique has been tested in few shale plays worldwide, most studies have been performed in the USA and Canada. Therefore, the foam fracturing technique is still comparatively novel for other countries around the world. 相似文献
6.
V. Bhola F. Swalaha R. Ranjith Kumar M. Singh F. Bux 《International Journal of Environmental Science and Technology》2014,11(7):2103-2118
An economic and environmentally friendly approach of overcoming the problem of fossil CO2 emissions would be to reuse it through fixation into biomass. Carbon dioxide (CO2), which is the basis for the formation of complex sugars by green plants and microalgae through photosynthesis, has been shown to significantly increase the growth rates of certain microalgal species. Microalgae possess a greater capacity to fix CO2 compared to C4 plants. Selection of appropriate microalgal strains is based on the CO2 fixation and tolerance capability together with lipid potential, both of which are a function of biomass productivity. Microalgae can be propagated in open raceway ponds or closed photobioreactors. Biological CO2 fixation also depends on the tolerance of selected strains to high temperatures and the amount of CO2 present in flue gas, together with SOx and NOx. Potential uses of microalgal biomass after sequestration could include biodiesel production, fodder for livestock, production of colorants and vitamins. This review summarizes commonly employed microalgal species as well as the physiological pathway involved in the biochemistry of CO2 fixation. It also presents an outlook on microalgal propagation systems for CO2 sequestration as well as a summary on the life cycle analysis of the process. 相似文献
7.
A two-dimensional brittle creep model for rock provides insight into the initiation of shear fracture along weak discontinuities in rock. The model accounts for material heterogeneity and introduces the concept of a mesoscopic renormalization to capture the cooperative interaction between cracks in the transition from distributed to localized damage. A series of shear creep tests on rock with discontinuities were performed to simulate the initiation and propagation of crack along a pre-existing weakness under sustained shear stress and normal stress. The investigation showed that shear stress level and the normal stress level might have significant effect on the long-term behavior of rock with weak discontinuities. Moreover, a case study of rock slope instability was also investigated, where the numerically simulated instability failure of rock slope with discontinuities showed that both tensile and shear damage at the weakest elements are the trigger for the failure surface initiation in the rock slope. Once damage occurs, redistributed stress concentrations would then intensify fracture propagation and coalescence within these damage zones, leading to the progressive development of a failure surface. Moreover, failure surface extending is not only dominated by the properties and the position of discontinuities but also influenced remarkably by the complex interaction between existing discontinuities and fracture propagation. The results are of general interest because they can be applied to the investigation of time-dependent instability in rock masses, to the mitigation of associated rock hazards in rock engineering, and even to a better understanding of the physical phenomena governing the stability of rock slope. 相似文献
8.
Single phase water flow through rock fractures 总被引：7，自引：0，他引：7
Flow analysis plays a major role in various geotechnical applications, and the understanding of flow mechanisms is essential for the development of a hydro-mechanical flow model suitable for underground excavations in rock. Discrete flow analysis through discontinuities is reviewed including empirical and analytical flow models. The influence of external loading on joint deformation and single-phase flow show that the surface roughness and aperture size are the prime factors influencing flow rate. Nevertheless, the idealization of natural fractures as smooth parallel plate joints is still followed in many numerical models, because of the simplicity of the cubic law when applied to fracture networks. A numerical study of water flow through a network of joints employing Universal Distinct Element Code (UDEC) is used to quantify the effects of joint orientation and external stress acting on idealized joints.It is found that, for the same joint spacing, the flow rate into an excavation depends on the boundary block size (Ab) relative to the excavation size (Ae). The inflow becomes excessive if Ab/Ae is less than 4, but becomes very small if Ab/Ae exceeds 8. 相似文献
9.
Ha H. Bui Jayantha K. Kodikara Abdelmalek Bouazza Asadul Haque Pathegama G. Ranjith 《国际地质力学数值与分析法杂志》2014,38(13):1321-1340
Segmental retaining wall (SRW) systems are commonly used in geotechnical practice to stabilize cut and fill slopes. Because of their flexibility, these systems can tolerate minor movements and settlements without incurring damage or crack. Despite these advantages, very few numerical studies of large deformations and post‐failure behavior of SRW systems are found in the current literature. Traditional numerical methods, such as the finite element method, suffer from mesh entanglement, thus are unable to simulate large deformations and flexible behavior of retaining wall blocks in SRW systems. To overcome the above limitations, a novel computational framework based on the smoothed particle hydrodynamics (SPH) method was developed to simulate large deformations and post‐failure behavior of soils and retaining wall blocks in SRW systems. The proposed numerical framework is a hybrid continuum/discontinuum approach that can model soil as an elasto‐plastic material and retaining wall blocks as independent rigid bodies associated with both translational and rotational degrees of freedom. A new contact model is proposed within the SPH framework to simulate the interaction between the soil and the blocks and between the blocks. As an application of the proposed numerical method, a two‐dimensional simulation of an SRW collapse was simulated and compared to experimental results conducted under the same conditions. The results showed that the proposed computational approach provided satisfactory agreement with the experiment. This suggests that the new framework is a promising numerical approach to model SRW systems. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
10.