EXPERIMENTAL INVESTIGATION ON GAS HYDRATE FORMATION IN PRESENCE OF ADDITIVE COMPONENTS

Additives were used to increase gas hydrate formation rate and storage capacity. Experimental tests of methane hydrate formation were carried out in surfactant water solutions in a high-pressure cell. Sodium dodecyl sulfate (SDS) and alkyl polysaccharide glycoside (APG) were used to increase hydrate formation. The effect of SDS on hydrate formation is more pronounced compared APG. Cyclopentane (CP) also improves hydrate formation rates while it cannot increase methane gas storage capacity.     

天然气水合物资源开采方法研究

自然界中存在大量的水合物,这些水合物已经被认为是将来重要的能源,本文分析了天然气水合物资源的特点,并综合介绍了现阶段提出的天然气水合物开采方法及模型,对比分析了典型开采方法,如热激发、降压和注抑制剂等的优缺点和经济性,评述了研究中存在的问题,并提出了今后研究的重点。     

外场作用下气体水合物形成分解试验研究

简述了磁场、微波、超声波的基本作用机理,介绍了国内外外场因素对气体水合物形成分解影响研究进展。最后指出开展相应研究的必要,并提出几点建议。     

甲烷水合物储气实验研究

1 INTRODUCTION Methane gas hydrates (MGH) are solid phase crystalline inclusion compounds (also called clathrates) that consist of a host water lattice with cavities in which methane gas is caged as a guest gas.Methane gas hydrate might contain 164 volumes (at standard pressure and temperature)of methane and 0.87 volumes of water per volume hydrate.     

在磁场作用下致冷剂气体水合物生成过程的图像

1 INTRODUCTION Gas hydrates are crystalline compounds that are formedfrom water and gas or volatile liquid such as natural gas, carbon dioxide and refrigerant[1].     

EFFECT OF MAGNETIZATION OF WATER ON INDUCTION TIME AND GROWTH PERIOD OF NATURAL GAS HYDRATE

The effect of diluted solution's magnetization on induction time and growth period of natural gas hydrate (NGH) has been investigated in quiescent reaction system at pressure of 4.5 MPa and temperature of 274 K with SDS as surfactant, by using volume fixed and pressure falling method. Experimental results show that magnetization will have effect on the induction time of NGH. After magnetization with magnetic field intensity of 0.33 T, the induction time of NGH has been reduced to 47 min (average) from 99 min (average) in which there is no magnetization. On the other hand, the induction time has been prolonged after magnetization of the diluted solution with magnetic field intensity of 0.05 T, 0.11 T, 0.22 T, 0.44 T. Especially with magnetic field intensity of 0.11 T, the induction time had even been prolonged to 431 min (average). The effect of magnetization on the growth period of NGH has not been found at the experimental condition.     

EXPERIMENTAL STUDY OF HFC-134a GAS HYDRATE FORMATION PROCESS

Refrigerant gas hydrates have brilliant prospects as cool storage material of air-conditioning system. In this paper, when the ratio of the weight of HFC-134a to that of water is 2.17%, systematic experiments have been carried out on the formation process of the HFC-134a gas hydrate including of the phase equilibrium, the influence of supercooling degree, and the influence of agitation. The results indicate that the critical decomposition temperature and the critical decomposition pressure of R134a hydrate is 283.4K and 414K respectively, the formation of gas hydrate was promoted with increasing the supercooling degree and the agitation. However, it is desired that the supercooling degree is smaller. Therefore, it is important problem that the study of optimum of supercooling degree for cool storage system.     

地面集输管线中水合物堵塞预测研究

天然气水合物一旦在地面集输管线中形成就会造成阀门堵塞、管道停输等严重事故,造成重大的经济损失。气流组成、温度、压力和含水量是影响地面集输管线中水合物形成的主要因素,此外,气井产量、管线长度、油管直径等对水合物的形成也有一定的影响。本文综合国内外有关水合物研究成果,并结合长庆气田某气藏生产过程中天然气水合物的生成条件及防治措施,对地面集输管线中天然气水合物堵塞的生成条件及预测模型进行了研究。     

H型气体水合物结构稳定性的分子动力学模拟

采用分子动力学模拟方法首次对H型气体水合物的晶体结构及稳定性进行了研究,得到H型气体水合物中各分子（原子）作用点之间的径向分布函数．在此基础上,通过计算水合物晶格上水分子的平动均方置换、取向均方置换以及取向自关联函数,考察了温度和客体分子对H型气体水合物结构稳定性的影响．结果表明：在水合物生成条件下,水合物晶体结构的稳定性依赖于晶体胞腔空穴中的客体分子;而对温度的变化则不太敏感．     

STUDY FOR NATURAL GAS HYDRATE CONVERSED FROM ICE

Natural gas hydrates are crystalline clathrate compounds composed of water and gases of small molecular diameters that can be used for storage and transport of natural gas as a novel method. In the paper a series of experiments of aspects and kinetics for hydrate formed from natural gas and ice were carried out on the industrial small scale production apparatus. The experimental results show that formation conditions of hydrate conversed from ice are independent of induction time, and bigger degrees of supersaturation and supercooling improved the driving force and advanced the hydrate formation. Superpressure is also favorable for ice particle conversion to hydrate. In addition, it was found there have an optimal reaction time during hydrate formation.     

EQUATION OF STATE BASED HYDRATE MODEL FOR NATURAL GAS SYSTEMS CONTAINING BRINE AND POLAR INHIBITOR

1 INTRODUCTIONIn the past two decades,as large reserves of hydrocarbons were discovered in the formof natural gas hydrates stored in deep oceans and permafrost regions such reserves mayturn out to become a tremendous energy source in the future.Among the challengingproblems emerged from offshore oil/gas exploration and production,hydrate research re-ceived new impetus.     

EQQUATION OF STATE BASED HYDRATE MODEL FOR NATURAL GAS SYSTEMS CONTAINING BRINE AND POLAR INHIBITOR

A new thermodynamic model for gas hydrates was established by combining the modified Patel-Teja equation of state proposed for aqueous electrolyte systems and the simplified Holder -John multi -shell hydrate model. The new hydrate model is capable of predicting the hydrate formation/dissociation conditions of natural gas systems containing pure water/formation water (brine) and polar inhibitor without using activity coefficient model. Extensive test results indicate very encouraging results.     

HCFC-141b制冷剂气体水合物生长过程的形态

通过实验观测了HCFC - 141b制冷剂气体水合物的生成过程 ,认为水相和制冷剂相在过冷的条件下在界面上局部成核 ,成核扩展至两相接触的整个界面 ,水合物的进一步生成是由于制冷剂相通过水合物层扩散到水相中形成的 .利用显微实验的生成图像计算了水合物晶体的生长速率 ,并与外冷实验中的晶体生长速率比较 ,认为扰动增大了制冷剂相和水相的两相相界面的接触维数 .     

天然气水合物开采模拟研究进展

介绍了天然气水合物(NGH)的结构及分解的基本特性;总结了电解质及沉积物对NGH形成及分解的影响,概括描述了NGH开采的几种可能方法;提出了NGH开采模拟进一步研究的方向。     

含氢气体水合物生成条件的测定和计算

利用全透明蓝宝石水合物静力学实验装置测定了12组含氢气体混合物（包括5个二元系、4个三元系和3个四元系）在纯水中的水合物生成条件.将Chen-Guo水合物模型应用于含氢体系水合物生成条件的计算,计算中选用PR状态方程以及刘昆元和汪文川提出的混合规则计算含氢气体混合物的组分逸度系数,并对混合规则中的二元交互作用参数进行了重新回归.实验测定的12组含氢气体混合物水合物生成条件的计算结果和实验结果符合得很好.     

EFFECT OF DIFFERENT OPERATION METHODS ON METHANE HYDRATE FORMATION

Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in gas hydrate. The relationships of hydrate rate, capacity and liquid temperature versus time were derived and three results were contrasted. The experimental results show lowtemperature and constant-pressure method is better than the other two methods because it's operation period is shorter and storage capacity is larger than the other two. Low-temperature and constant-pressure method is the best method. So new method will be new research objective.     

蓄冷空调及气体水合物蓄冷技术

从蓄冷空调的应用背景出发,简述了蓄冷空调技术的发展与现状,并在此基础上详细介绍了气体水合物蓄冷技术,从气体水合物蓄冷工质的选择、气体水合物结晶\熔解特性改善及气体水合物蓄冷装置设计3个方面对目前的研究现状进行了描述,最后提出了一些今后应该重点展开的研究方向     

添加剂对堇青石合成温度及热膨胀系数的影响

采用煤系高岭土、滑石、镁砂为原料合成堇青石,主要探讨了添加剂对合成堇青石的性能影响。通过X-Ray衍射(XRD)分析,用K值法求算合成堇青石矿物相含量,在保证矿物相含量的前提下,探讨添加剂对热膨胀系数的影响。研究结果表明:添加剂的使用均能降低合成堇青石的热膨胀系数,不加添加剂的热膨胀系数为2.04×10-6/℃(20～1100℃);加入碳酸钡热膨胀系数为α=1.84×10-6/℃(20～1100℃);加入碳酸锂热膨胀系数为α=1.86×10-6/℃(20～1100℃)。     

甲烷水合物在纯水中的生成动力学

引言一些低分子量气体,如石油和天然气中C_1～C_4轻烃、氮气、硫化氢、二氧化碳和惰性气体等,在一定压力和温度的条件下可与水形成一类笼形结构的冰状晶体,即所谓的气体水合物．气体水合物是一类较为特殊的包络化合物：主体水分子通过氢键相互结合形成一种内含空隙的笼形框架,客体分子则被笼罩于这些空隙中．主、客体分子之间的作用力为vanderWaals力．水合物晶体最为常见的两种结构分别称为结构I（体心立方构型）和结构Ⅱ（金刚石构型）．甲烷和水形成结构I水合物．文献阐述了开展水合物生成动力学研究的重要意义．但由于水合物生成…     

水合物法储存乙烯实验研究

提出了以水合物法储运乙烯,选用阴离子表面活性剂十二烷基硫酸钠(SDS)作为乙烯水合物的生成促进剂进行实验研究,考察了SDS对乙烯水合物生成的促进作用以及乙烯水合物在低温下的热稳定性。结果表明:SDS对乙烯水合物的生成速率和储气密度都有较大提高,对其促进原因进行了初步分析;实验测定乙烯水合物在263～269K的分解平衡压力范围是0.244～0.460MPa,在263～271K进行常压分解时,其分解率随温度升高而升高,在温度低于267K时,乙烯水合物的平衡分解率将降到23.7％以下,其中263K的分解率为5.6％。