论文题目 | May sediments affect the inhibiting properties of NaCl on CH4 and CO2 hydrates formation? An experimental report |
论文题目(英文) | May sediments affect the inhibiting properties of NaCl on CH4 and CO2 hydrates formation? An experimental report |
作者 | 李艳 |
发表年度 | 2022-04 |
卷 | 359 |
期 | |
页码 | 119300 |
期刊名称 | Journal of Molecular Liquids |
摘要 |
在有或没有氯化钠的情况下,测量了甲烷和二氧化碳凝结水合物的平衡性。测试了两种不同的盐浓度:0.030和0.037 wt%。结果与文献中已经存在的这些物种的相平衡数据进行了比较。尽管有盐,但多孔介质被发现促进了这一过程,主要是增加了表面/体积比和改善了传热。在有盐的情况下,沙子随着温度的变化而对过程产生不同的影响:当温度高于3-5℃时,它促进了过程,而当温度低于这个范围,但仍高于冰点时,它就起到了抑制作用。然而,这些结果只有在温度高于冰点时才能被认为是真实的。 由于冰水与凝结水合物的相似性,拉曼微观测量被用来收集有关沉积物、盐和温度对水的OH拉伸振动的影响的信息。获得的结果允许阐明在不同的温度条件下(15℃和-15℃),向液态水中添加氯化钠和或沉积物是如何影响水的氢键的。具体来说,当与NaCl浓度相关时,OH拉伸振动的变化表明,沉积物的存在部分地抑制了冰水中的盐效应,这可能是由于与沉积物的硅醇基的亲水作用。SEM测量显示了在不同实验条件下沉积物和冰的形态信息。 |
摘要_英文 |
The equilibria of methane and carbon dioxide clathrate hydrates were measured in presence of a pure-quartz porous sand, with and without NaCl. Two different salt concentrations were tested: 0.030 and 0.037 wt%. Results were compared with phase equilibrium data already present in literature for these species. Despite salt, the porous medium was found to promote the process, mainly for the increased surface/volume ratio and for the improved heat transfer. In presence of salt, sand affected the process differently as a function of temperature: at values higher than 3 – 5 °C, it promoted the process, while for values lower than this range, but still greater than the ice-point, it acted as an inhibitor. However, these results can be considered true only for temperatures above the ice point. Due to similarity of ice water with clathrate hydrates, Raman microscale measurements were performed to gather information about the influence of sediments, salt, and temperature on OH-stretching vibrations of water. The obtained results allowed to clarify how the addition of NaCl, and or sediments to liquid water, under different temperature conditions (15 °C and ?15 °C), influenced the water hydrogen bonds. Specifically, the changes of OH-stretching vibrations, when correlated with the NaCl concentrations, demonstrated that the presence of sediments partially inhibited the salt effects in the ice water probably due to hydrophilic interactions with the silanol groups of sediments. SEM measurements showed morphological information on sediments and on ice in different experimental conditions. |
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