Towards Zero Carbon Emissions: Novel Low Pressure Molecular Natural Gas/CO2/H2 Storage and Separation using Semi-Clathrates

在该实验室中进行的最新工作已经揭示了相当大体积的低分子量气体，包括甲烷、CO2和氢气，可以掺入一类鲜为人知的笼形水合物的结构腔中（或“气体水合物”），即季铵盐的半笼形水合物（QAS，例如四正丁基溴化铵（TBAB），在非常低的压力（至大气压）和环境温度（30 ℃）下。除了热力学稳定性的有利条件之外，QAS水合物还具有许多其它有利的性质，包括：1.它们可以相对容易地形成/解离（通过适度的压力和/或温和的温度变化）2.储存大量气体的潜在能力（在我们的初步实验中，CH 4和H2分别达到62和52体积/体积）3.在气体吸收/水合物生长期间强烈区分不同气体的能力（由QAS类型和水溶液浓度控制）4.生产易于运输（例如在间歇反应器、管道中）的水合物-水浆的能力5。非常低的母液蒸气压（类似于普通盐溶液），这意味着水合物释放的气体具有非常高的纯度（不像其他挥发性有机水合物促进剂，如THF/四氢呋喃）6。与其它有机水合物促进剂（例如，THF）和气体处理中使用的化学品（例如，这些性质使QAS半包合物具有作为工业储存/运输和气体分离的新工具的显著潜力。基于迄今为止的结果，该技术已经申请了专利（GB 0511546.4：一种用于气体储存、运输、调峰和能量转换的方法（2005））。这里提出的工作的目的是通过一个密集的综合实验和理论研究，以评估这个家庭的水合物形成的潜力。该技术将使用三种气体进行研究，这三种气体是专门针对其在全球能源行业中的重要性而选择的，即天然气（NG）/甲烷（CH 4），二氧化碳（CO2）和氢气（H2）。

Recent work carried out in this laboratory has revealed that considerable volumes of low molecular weight gases, including methane, CO2 and hydrogen, can be incorporated into structural cavities of a class of little known clathrate hydrates (or 'gas hydrates'), namely the semi-clathrate hydrates of Quaternary Ammonium Salts (QAS, e.g. tetra-n-butylammonium bromide (TBAB) at very low pressures (to atmospheric) and ambient temperature (30 oC). In addition to favourable conditions of thermodynamic stability, QAS hydrates have numerous further advantageous properties, including:1. The relative ease with which they can be formed/dissociated (by modest pressure and/or gentle temperature change) 2. The potential capacity to store large volumes of gas (62 and 52 vol/vol achieved for CH4 and H2 respectively in our preliminary experiments)3. The capability to strongly discriminate between different gases during gas uptake/hydrate growth (controlled by QAS type and aqueous concentration)4. The ability to produce readily transportable (e.g. in batch reactors, pipelines) hydrate-water slurries5. A very low parent liquid vapour pressure (similar to common salt solutions), meaning gases released from hydrates are of a very high purity (unlike for other volatile organic hydrate promoters such as THF/tetrahydrofuran)6. A relatively low toxicity compared with other organic hydrate promoters (e.g., THF) and chemicals used in gas processing (e.g., amine solutions)These properties give QAS semi-clathrates significant potential as a novel tool for the industrial storage/transportation and separation of gases. Based on the strength of results to date, a patent for this technology has been filed (GB 0511546.4: A method for gas storage, transport, peak-shaving, and energy conversion (2005)). The aim of the work proposed here is to assess the potential of this family of hydrate formers through an intensive integrated experimental and theoretical study. The technology will be investigated using three gases chosen specifically for their current importance in the global energy industry, namely natural gas (NG)/methane (CH4), carbon dioxide (CO2) and hydrogen (H2).