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Natural Gas
Published in Roy L. Nersesian, Energy Economics, 2016
Clathrate compounds are water molecules that under certain conditions bond to form an ice-like cage that encapsulates a gas molecule, which if methane is called methane hydrate.137 Methane hydrates are essentially natural gas molecules trapped in a lattice of ice whose structure is maintained in a low-temperature and moderate-to-high pressure environment. Methane hydrates can be shaped into an ice ball like those carefully sculpted by Calvin in the “Calvin and Hobbs” comic strip to throw at Suzie. The only difference is that a methane hydrate ice ball can be ignited. One cubic meter of methane hydrates contains enough embedded natural gas that, when released, expands to an incredible 160 cubic meters at atmospheric pressure.
Measuring stiffness of soils in situ
Published in Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto, Computer Methods and Recent Advances in Geomechanics, 2014
Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto
Gas hydrates are crystalline clathrate compounds made of water and a low molecular gas like methane. Gas hydrates are generally present in oil-producing areas and in permafrost regions. Methane hydrate deposits can lead to large-scale submarine slope failures, blowouts, platform foundation failures, and borehole instability. Gas hydrates constitute also an attractive source of energy as they are estimated to contain very large reserves of methane. Hydrate formation, dissociation and methane production from hydrate bearing sediments are coupled Thermo-Hydro-Mechanical (THM) processes that involve, amongst other, exothermic formation and endothermic dissociation of hydrate and ice phases, mixed fluid flow and large changes in fluid pressure. A comprehensive THM formulation is briefly presented here. Momentum balance, mass balance and energy balance equations take into consideration the interaction among all phases (i.e. solid, liquid, gas, hydrates and ice). Constitutive equations describe the intrinsic THM behavior of the sediment. Simulation results conducted for hydrate bearing sediments subjected to boundary conditions highlight the complex interaction among THM processes in hydrate bearing sediments.
Adsorption and biodegradation functions of novel microbial embedding polyvinyl alcohol gel beads modified with cyclodextrin: a case study of benzene
Published in Environmental Technology, 2019
Nan Wu, Xiaofang Li, Guoshuai Huang, Peng Pan, Chang Wang, Xinyuan Liu, Ming Zeng
Cyclodextrin (CD) is a kind of oligosaccharide composed of several D-glucopyranose units under a ring arrangement. The molecules are in a hollow cylinder with a narrow width and the inner cavity is relatively hydrophobic, while all hydrophilic groups stay outside the cylinder. This chemical compound can form a clathrate compound with other subject substances embedded in the inner cavity, including contaminants. Due to its low cost and appropriate inner diameter, β-CD is the most widely used. So far, CD polymers have been applied in the field of environmental protection, especially detoxification of heavy metals and organic contaminants [11]. For example, β-CD polymer was found to be capable of removing dissolved estrogens over a wide dose range in sewage effluent [12].