氯化钠在乙二醇溶液中结晶动力学的研究

发布时间：2018-05-14 06:54

本文选题：氯化钠 + 乙二醇　；参考：《西南石油大学》2015年硕士论文

【摘要】：目前,越来越多的乙乙二醇再生脱盐系统被应用于深水气田开发的依托平台上,其中尤为关键的脱盐单元主要是将富乙二醇溶液中的固态盐颗粒及液态盐从乙二醇再生脱盐系统中去除,以减轻设备、管线的腐蚀。盐在乙二醇溶液中的结晶速率将直接影响脱盐系统的脱盐效率,同时所结晶出的盐颗粒的粒度大小也将影响分离设备的选择与参数的设定,为了提高脱盐系统的脱盐效率以及为设备选型提供理论依据,有必要对盐在乙二醇中的结晶行为进行系统的研究。本文以钠盐在乙二醇溶液中结晶的角度研究钠盐在乙二醇中的热力学性质、动力学性质以及不同因素对钠盐结晶动力学和粒度分布的影响规律,为脱盐工艺及设备的选择和参数的优化提供数据支撑和理论依据,对实现乙二醇再生脱盐系统设计国产化具有重要的意义。本文针对钠盐在乙二醇中的结晶过程,开展了以下几方面的研究： (1)采用静态法测定了不同温度下氯化钠在乙二醇中的溶解度,采用Ori西n软件对实验数据进行拟合,得到了溶解度经验方程。 (2)采用激光法测定了氯化钠在乙二醇中的超溶解度,继而得到了介稳区,并探讨了温度对介稳区宽度的影响。结果表明：在实验条件下,氯化钠在乙二醇溶液中的极限过饱和度较小；低于393.15K的介稳区宽度较宽且稳定,高于393.15K的介稳区宽度将随温度的升高而逐渐变窄。 (3)测定了氯化钠在乙二醇溶液中的诱导期,探讨了不同过饱和度对诱导期的影响。结果表明：过饱和度越高,诱导期越小。 (4)采用间歇动态法研究了氯化钠在乙二醇溶液中的结晶动力学,回归得到了氯化钠在乙二醇中的成核速率方程和生长速率方程,并在此基础上讨论了过饱和度、温度等因素对氯化钠结晶动力学的影响。结果表明：温度升高,生长速率与成核速率都会增大,且成核更容易发生；增大过饱和度,生长速率与成核速率都会变大；增大悬浮密度,成核速率也会随之变大。 (5)通过室内实验研究了温度、真空度等因素对氯化钠晶体粒度分布的影响规律。结果表明：在同等条件下,温度越高,晶体的粒度分布越分散,平均粒度越小；真空度越高,晶体的粒度分布越分散,平均粒度越小；固液比过高或过低都会导致晶体的平均粒度变小；停留时间过长或过短都将导致晶体的平均粒度变小。
[Abstract]:At present, more and more ethyleneglycol regenerative desalination systems have been applied on the platform of deep water gas field development. The most important desalting unit is the removal of solid salt particles and liquid salt from ethylene glycol regeneration desalination system in order to reduce the corrosion of equipments and pipelines. The crystallization rate of salt in ethylene glycol solution will directly affect the desalination efficiency of the desalination system, and the size of the salt particles will also affect the selection of separation equipment and the setting of parameters. In order to improve the desalting efficiency of desalting system and provide theoretical basis for equipment selection, it is necessary to systematically study the crystallization behavior of salt in ethylene glycol. In this paper, the thermodynamic properties, kinetic properties of sodium salts in ethylene glycol and the influence of different factors on the crystallization kinetics and particle size distribution of sodium salts in ethylene glycol solution were studied. It provides data support and theoretical basis for the selection of desalting process and equipment and the optimization of parameters. It is of great significance for the design of ethylene glycol regeneration desalting system. In this paper, the crystallization process of sodium salt in ethylene glycol has been studied in the following aspects: 1) the solubility of sodium chloride in ethylene glycol at different temperatures was determined by static method. The experimental data were fitted by Ori software and the empirical equation of solubility was obtained. (2) the supersolubility of sodium chloride in ethylene glycol was determined by laser method, and the metastable region was obtained, and the influence of temperature on the width of metastable zone was discussed. The results show that the limit supersaturation of sodium chloride in ethylene glycol solution is small under the experimental conditions, the width of the metastable zone below 393.15K is wider and stable, and the width of the metastable zone above 393.15K will become narrower with the increase of temperature. The induction period of sodium chloride in ethylene glycol solution was determined and the influence of supersaturation on induction period was discussed. The results showed that the higher the supersaturation, the smaller the induction period. The crystallization kinetics of sodium chloride in ethylene glycol solution was studied by intermittent dynamic method. The nucleation rate equation and growth rate equation of sodium chloride in ethylene glycol were obtained by regression, and the supersaturation was discussed. Effects of temperature and other factors on crystallization kinetics of sodium chloride. The results show that the growth rate and nucleation rate will increase with the increase of temperature, and the nucleation rate will increase with the increase of supersaturation, the growth rate and nucleation rate will increase with the increase of the supersaturation, and the nucleation rate will also increase with the increase of the suspension density. The effects of temperature, vacuum and other factors on the particle size distribution of sodium chloride crystal were studied by laboratory experiments. The results show that under the same conditions, the higher the temperature, the more dispersed the particle size distribution and the smaller the average particle size, the higher the vacuum degree, the more dispersed the particle size distribution and the smaller the average grain size. Too high or too low solid-liquid ratio will lead to the average particle size of the crystal become smaller, and if the residence time is too long or too short, the average particle size of the crystal will become smaller.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE39;O781

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