【作者】 刘佳；

【导师】 周理；

【作者基本信息】 天津大学 ， 化学工程， 2013， 博士

【摘要】 气体水合物，作为种重要的笼型化合物，具有其独特的性质。随着这门学科的不断发展，气体水合物理论得到不断的丰富。目前人们已经开始将气体水合物应用到各化工领域当中。在这些应用当中，最具有代表性的便是油气领域的天然气存储。天然气作为一种清洁可再生能源，其在能源结构中的比例日益加大，传统的储运方式的不足日益显露。天然气水合物（NGH）存储方法一直以来作为比较有前途的新型储运方式，吸引了研究学者的广泛注意。利用多孔介质实现在纳米空间内进行的天然气湿储（WNG），克服了NGH以往的缺点，提高了天然气水合物的生成速率，微尺度下更有利于水合物分解，使充放气速度得到提升。采用此法，降低了存储压力，节约了储运成本。本文通过分析甲烷在多孔材料内生长情况，确立了最适于天然气湿储的孔径范围是1.6nm-3nm。基于此结果，本文尝试采用多种活化方法，最终发现，孔内水活化法可以对材料孔径进行较好的控制，并制得适用于天然气存储的材料WAC-4，其表面积高达3456m2/g，其1.6nm-3nm处孔容高达0.97ml/g。WAC-4湿炭上甲烷最高重量储量可达64%，在充放气实验中，10MPa下其最甲烷体积储量为202V/V（STP)。N2/CH4分离一直以来是吸附界的难题，我国目前加大了对煤层气页岩气的开发利用，对氮气甲烷高效分离技术的需求更为迫切。纳米空间内水合物法分离氮甲烷是一种新的尝试，文中通过添加四氢呋喃，降低了两种气体的水合物生成压力，使水合物法和变压吸附工艺结合成为可能。实验表明，在多孔物质内添加四氢呋喃溶液，甲烷水合物生成压力降到0.35MPa，氮气水合物生成压力降为1.5MPa，利用两者生成压力的明显差异，采用变压吸附的工艺，对浓度56.65%的原料气进行富集。在不同操作压力下得到最高富集浓度为75%。通过分析显示，在纳米尺度空间内，由于水合物尺寸极小，水合物笼型结构一旦生成，氮气甲烷分子均可进入笼内。故此法不宜用于N2/CH4分离乙烯作为唯一可在超临界区域内生成气体水合物的物质，其有着更为独特的应用领域，如超临界水合物萃取，本文对纳米空间内乙烯水合物进行了系统的研究，发现乙烯水合物在多孔炭材料上有着独特的水合物生成行为。乙烯在孔内生成气体水合物可分两步完成，首先是乙烯分子进入大笼内，构成水合物晶体，在压力足够大的时候，乙烯分子开始填充进小笼，而材料的孔径对水合物的这种行为有着重要的影响。随着孔径的增加，这种分步形成的现象，变得模糊，最终消失。CO2作为温室气体，其填埋一直是个重要的课题，以多孔硅胶模拟海地硅酸盐环境，研究CO2水合物的生成行为有着重要的意义。本文考察了三种硅胶上CO2水合物的生成行为，发现孔径对CO2水合物的生成有着重要的影响，当孔径过大时，水合物很难生成。更多还原

【Abstract】 The gas hydrate, an important clatherate compound.Along with its development,the gas hydrate theory obtains rich. At present people already started to apply the gashydrate in many chemical industry areas. The gas hydrate has many application, inwhich natural gas storage is representatively. The natural gas take one kind of cleanrenewable energy, the traditional storage and transport way is insufficiency. NaturalGas Hydrate storage method (NGH) take continuously the most promising way, whichattracted scholar’s widespread attention. NGH carried on in nanometer space (WNG)overcome the former shortcoming, WNG enhanced the hydrate production speed,improve the speed of charge/discharge process. Uses this way, under10MPa theuptake of methane reach150V/V(STP）at2oC, reduced about half pressure comparewith CNG, saved the cost. In present work，through analyzed the condition of methanehydrate in the porous material, we established the optimal pore size for WNG is1.6nm-3nm. Based on the result, many different method for material preparation wereattempted，finally the method which use water activated in pore was found beensuitable。By this method, the suitable material was obtain for WNG named WAC-4with surface area3456m2/g, and pore volume(1.6nm-3nm)0.97ml/g. The maximmethane uptake on wet WAC-4reach64%, the chargeable quantity of methane reach202V/V(STP) at10MPa.The separation of N2, CH4is always considered as a most difficult problem. Withthe strengthen of exploitation of coal bed methane and shale gas, the new efficienttechnology for N2/CH4separation is necessary. N2/CH4separation via gas hydrate innano-space is a neo attempt. In the article by add THF solution to the pore ofWAC-4, both gas hydrate formation pressures reduced, causes it possible to combinegas hydrate separation with the PSA craft. The result indicated, in THF solutions, themethane hydrate formation pressure in pore drop arrives0.35MPa, the nitrogenhydrate formation pressure reduces to1.5MPa, base on the obvious difference of twoformation pressure, methane concentration experiment via PSA craft were carried on.Under the different pressure the feed gas can enrich from56.5%to75%. Innano-space, the scale of hydrate cystal formed in the pore is much more small, onlyseveral cells, once hydrate cavities formed, the nitrogen and methane may both enterin the cage. Ethylene can form gas hydrate at its critical temperature, it have the more uniqueapplication such as supercritical gas hydrate extraction. In present work, ethylenehydrate formation behavior in nano-space were studied and discovered the uniquehydrate formation behavior. On the porous material, the ethylene hydrate formaitonprocess possible can divide into two steps, the first step the ethylene molecule entersin the L cage of hydrate crystal, the second step, the ethylene molecule fill into S cage,when pressure is enough. Pore size of material has an important influence on ethylenehydrate formation behavior. Along with the pore size increase, the phenomenon oftwo step formation becomes fuzzy, finally vanished.CO2a major greenhouse gas, which contribute to global warming. It’ssequestration method is always an important topic include buried in seabed.Submarine sediments are made of naturally porous materials that are very similar toporous silicates. Simulates submarine environment, CO2hydrate formation behavioron several types of silicon-gels were studied. The results indicate the pore size hasvery impormtant effect on CO2hydrate formation. When the pore size is7nm orgreater, such as in SG-C, the CO2hydrate formation is difficult since the impetus ofpore space for hydrate formation disappears.更多还原