Intercalation of Gas Hydrates in Clays

Guggenheimeim-0207770该提案的工作假设是，粘土/甲烷-天然气水合物复合物将在低温和高气压下在适当的水饱和条件下形成。在一系列的初步实验中，我们获得了这些复合物确实可以在这些条件下形成的证据。 在这些实验中，我们使用了一个环境室，能够承受-100至200 oC的温度和75 bar的气压。 该室，我们开发的内部，允许X射线扫描从0到70度2 θ。我们建议检查Na交换和Ca交换蒙脱石和甲烷在适当的条件下形成粘土/甲烷气体水合物复合物。 此外，我们将研究甲烷和NH 4-交换蒙脱石之间可能的相互作用。我们的目的是确定粘土的组成范围，使气体水合物插入粘土结构。 然后，我们将确定这些粘土/气体水合物复合物形成的P-T条件，以及掺入粘土中的气体水合物的量。粘土/天然气水合物复合物的发现引入了一类新的材料，这应该是矿物学，地球化学和材料科学的兴趣。 与天然气水合物一样，这些新的复合物：（1）可能会出现在深海和极地地区（例如，永久冻土，南极冰），（2）可能涉及海底沉积物的稳定性，（3）可能存在于火星上。 粘土/天然气水合物复合物的稳定范围可能会扩展天然气水合物化合物的稳定范围。 此外，粘土/天然气水合物复合物可能储存大量的甲烷和其他碳氢化合物，因此，这些复合物可能在气候变化中发挥重要作用，就像已经提出的天然气水合物一样。

GuggenheimEAR-0207770The working hypothesis of this proposal is that clay/methane-gas hydrate complexes will form under appropriate water-saturated conditions at low temperatures and high gas pressures. In a series of preliminary experiments, we obtained evidence that these complexes indeed can form at these conditions. In these experiments we used an environmental chamber, capable of temperatures from -100 to 200 oC and gas pressures to 75 bars. This chamber, which we developed in-house, allows X-ray scans from 0 to 70 degrees two theta.We propose to examine Na-exchanged and Ca-exchanged montmorillonite and methane under the appropriate conditions to form clay/methane-gas hydrate complexes. In addition, we will examine possible interactions between methane and NH4-exchanged montmorillonite. Our intent is to determine the compositional range of clays that allow gas hydrates to intercalate into clay structures. We will then determine the P-T conditions where these clay/gas-hydrate complexes form, as well as the amounts of gas hydrates that are incorporated in the clay. The discovery of clay/gas-hydrate complexes introduces a new class of materials, which should be of interest in mineralogy, geochemistry, and materials science. As with gas hydrates, these new complexes: (1) may be expected to occur in deep ocean and polar regions (e.g., permafrost, Antarctic ice), (2) may be involved in submarine sediment stability, and (3) may be present on Mars. It is probable that the stability range of clay/gas-hydrate complexes will extend the stability range of gas-hydrate compounds. Also, clay/gas-hydrate complexes may store significant quantities of methane and other hydrocarbons, and thus, these complexes may play an important role in climate changes, much like what has been proposed for gas hydrates.