多孔介质中气体水合物的成核研究

 研究气体水合物成核过程是水合物动力学研究的重要内容之一，有助于人们更好地认识气体水合物生成过程，掌握其动力学规律，进而有效的对水合物进行开发利用。本研究通过在实验室内模拟实验合成CO₂水合物，利用电学探测技术研究其成核过程，建立了水合物成核速率与阻抗关系的模型，并结合具体实验条件对模型进行拟合求解, 得到水合物成核速率变化趋势。同时发现水合物生成诱导时间受水分子记忆效应的影响。     

海底甲烷水合物溶解和分解辨析及其地质意义

甲烷水合物的溶解和分解过程是甲烷水合物成藏的关键科学问题，同时也是造成环境灾害事件的重要因素。近年来，在阅读甲烷水合物相关文献中发现有些作者对甲烷水合物溶解和分解的复杂动力学过程产生了一些混淆，并由此可能对甲烷水合物的成藏机理及其对环境气候变化影响的认识造成偏差。基于前人的大量研究成果，并结合作者多年对甲烷水合物形成和分解动力学过程的系统研究，认为海底存在一种甲烷气体的动态存储与排泄平衡作用，甲烷水合物的溶解和分解是海底甲烷气的主要排泄方式，也是甲烷水合物失稳后的2种不同的重要过程，同时，海底甲烷气的排泄量、运移方式和排放速率都与甲烷水合物成藏与否密切相关，因此深入认识甲烷水合物溶解和分解过程的控制机理，对海底甲烷水合物形成机制、成藏过程的研究和对全球碳循环、气候变化的评估有着重要的科学意义。     

氢氧化钠标准溶液制备和标定影响因素探讨

以0.1mol/L氢氧化钠标准溶液为例,对0.1mol/L氢氧化钠标准溶液制备和标定过程影响因素进行分析探讨并进行有效的控制,为分析检测提供技术保证。     

4,4,5-三甲基-4H-吡唑-3-甲酸甲酯的合成研究

本文介绍了4,4,5-三甲基-4H-吡唑-3-甲酸甲酯的合成方法。以乙酰丙酮酸甲酯为起始原料,碘甲烷为甲基化剂,碳酸铯为催化剂,在丙酮溶剂中进行甲基化,得到中间体3,3-二甲基-2,4-二氧-戊酸甲酯,然后直接与水合肼环化反应得到目标产物,总收率为73.1%,产物结构经过1H NMR、13C NMR确证。     

全球待发现油气资源分布及启示

油气资源具有不可再生性,随着常规油气资源不断枯竭,为满足人类日益增长的能源需求,必须寻找新的替代油气资源。本文综合多家能源研究机构的最新研究成果,认为全球待发现的油气资源主要来自深层、深水、非常规、北极、天然气水合物等,未来的油气勘探开发挑战主要表现在三个方面:一是需要开发的资源类型更加多样化,且不同类型的资源都面临着一定的技术挑战;二是待开发的油气资源储藏特征更为复杂,降低成本和提高效率的压力越来越大;三是管理安全与环境风险的任务越来越重。未来的资源机会极具挑战性,行业发展更加依赖技术创新。     

Tuning Surface Composition of Ni-Pt/CeO2 Catalyst for Hydrogen Generation from Hydrous Hydrazine DecompositionEI北大核心CSCD

Hydrous hydrazine (N2H4 center dot H2O) is a water-like liquid with a high hydrogen density (8%, mass fraction), relatively low cost, and satisfactory stability under ambient conditions. Owing to these favorable attributes, N2H4 center dot H2O has attracted considerable attention as a promising hydrogen carrier for on-board or portable applications. The synthesis of highly active and selective catalysts is a central issue in developing practical hydrous hydrazine-based hydrogen generation systems. The development of high-performance catalysts requires fundamental knowledge of the correlation between the surface composition of the catalyst and its catalytic performance. In the present work, a supported Ni-Pt/CeO2 bimetallic nanocatalyst was prepared by a one-pot co-reduction method, and its use for catalyzing hydrous hydrazine decomposition to generate hydrogen was reported. The surface composition of the Ni-Pt/CeO2 catalyst was regulated by heat treatments under different atmospheres, such as air, NH3, H-2, and CO and at different temperatures. It was found that changing the annealing conditions may result in altered Ni/Pt ratio at the catalyst surface, and as a consequence the catalytic performance can be tailored. When the molar Ni/Pt ratio at the catalyst surface was 0.8 similar to 1.14, the catalyst has been found to possess remarkable catalytic activity towards hydrous hydrazine decomposition. Additionally, it was found that incorporation of non-metallic N element on the catalyst surface may result in remarkably improved catalytic activity of NiPt/CeO2 towards hydrous hydrazine decomposition. This finding may open new avenues for the development of high-performance catalyst for promoting hydrogen generation from hydrous hydrazine.     

油水乳液强化分离矿井瓦斯的特性

为探究油水乳液体系瓦斯水合物分离特征,利用高压可视搅拌水合分离实验装置结合气相色谱仪,研究了2℃条件下油水体积比、驱动力对瓦斯水合物生长速率和CH4回收率的影响,计算了气体消耗量、水合物体积生成量、水的转化率。结果表明:油水乳液体系水合物浆液具有良好的流动性;相同温度压力条件下,油水体积比1∶1体系瓦斯水合物平均生长速率和CH4回收率均优于7∶3体系,但水合物浆液流动性不及7∶3体系;瓦斯水合物平均生长速率、气体消耗量、水合物体积生成量、水的转化率均随着驱动力的增大而增大;油水体积比1∶1条件下CH4回收率和分离因子随着驱动力的增大而先增大后减小,驱动力为3.0 MPa(压力为7.78 MPa)时CH4回收率最大为24.36%。     

广西及周边地区水合肼市场分析

介绍了水合肼产品及其应用领域,概述了水合肼的国内市场状况,分析了广西及周边地区水合肼的消费情况。市场分析结果表明水合肼作为一种液体产品,本公司虽有生产的原料优势,但市场销售优势并不明显,建设水合肼项目具有较大的市场风险。     

Chemical and phase equilibria calculation of α-pinene hydration in CO2-expanded liquid

Modeling of chemical and phase equilibria of α-pinene hydration in subcritical CO₂ was carried out by calculation. A simplified scheme of the conversion includes 6 reaction routes. Thermochemical and physicochemical parameters of individual compounds (T_cr, P_cr, T_b, (298.15 K), (298.15 K), C_p (T), ω) were preliminary estimated. Phase diagrams of the model reaction mixtures were calculated, coordinates of the critical point were found, and the region of subcritical parameters T and P, where the initial mixture divides into the gas phase and CO₂-expanded liquid, was located. Dependence of the products distribution and yield of CO₂-expanded liquid on the reaction temperature and pressure was studied. The reaction equilibrium as a function of temperature and pressure was determined, and heat effects of all reactions under consideration were calculated. The drift of critical parameters versus reaction mixture composition was examined. It was shown that during the hydration and alcohols accumulation the critical pressure of reaction mixture increases continuously, the critical temperature at first elevates and then begins to decrease, and the phase diagrams starts to degenerate. If amount of alcohols becomes more than 80 mol%, the mixture has no critical point and cannot pass to a supercritical state.     

Comparative study of hydrogen,argon, and xenon uptake into a propane hydrate

The rate of absorption of hydrogen, argon, and xenon into a Type II propane clathrate hydrate has been studied. The propane hydrate is synthesized from 250‐μm ice grains, is estimated to have a porosity of 65% and has roughly the consistency of chalk. Hydrogen is rapidly absorbed by the hydrate sample and approaches the equilibrium vapor pressure in an hour before a very slow residual absorption process ensues. For an initial hydrogen pressure of 1.5 MPa, about 4.5% of the available 5¹² cages are occupied by hydrogen after 1 h, and 4.9% after 18 h. In contrast, for both argon and xenon significantly more gas is absorbed by the hydrate but at a much slower rate: about 5% as fast for xenon and 1% as fast for argon. We conclude that hydrogen readily diffuses through the propane hydrate microcrystal structure, while argon and xenon are probably absorbed by growing new double hydrate while consuming the propane hydrate. Although considerably higher pressures would be required to store significant quantities of hydrogen in propane hydrate, it appears that the crystal can be loaded and emptied in relatively short times. © 2010 American Institute of Chemical Engineers AIChE J, 2010