甲酸甲酯-甲醇汽液相平衡研究

测定了 1 0 1 3kPa以及 2 0 2 6kPa下甲酸甲酯 甲醇的二元汽液相平衡数据 ,并用Wilson、NRTL、UNIQUAC方程对数据行了关联。     

CH4- CO2体系固体CO2形成条件的预测模型

采用膨胀机制冷工艺回收天然气中的乙烷时,膨胀机出口与脱甲烷塔顶部的温度较低,容易发生CO₂冻堵,影响装置的正常运行。准确预测固体CO₂的形成条件,有助于及时采取相应的措施调整凝液回收装置的操作工况,避免CO₂冻堵。为此,分析了CO₂固体的形成条件,根据相平衡原理,采用标准形式的Peng Robinson状态方程建立了液固平衡模型（LSE）和气固平衡模型（VSE）,据此分别对CH₄-CO₂2气相体系和CH₄-CO₂2液相体系中的固体CO₂形成温度进行了计算,并与用HYSYS软件预测的固体CO₂形成温度进行了比较。结果表明：该计算模型的准确度较高,与实验数据的误差在2 ℃以内;而HYSYS软件预测的CH₄-CO₂气相体系的固体CO₂形成温度较实验数据偏高1～5 ℃,预测的CH₄-CO₂液相体系的固体CO₂形成温度较实验数据偏低1～6 ℃。     

水和载体对K2CO3催化甲醇与CO2合成碳酸二甲酯反应的影响

K2CO3催化剂在CO2与甲醇直接合成碳酸二甲酯(DMC)反应中表现出较高的催化活性,但催化作用机理仍不够明确,尤其是水在反应中的作用。实验考察了无脱水剂情况下向反应体系中加入少量水以及不同的载体对DMC合成反应的影响。结果表明:少量水的存在可以增加催化活性,但并不改变生成DMC的反应平衡,水在其中起到溶解K2CO3,增加其在甲醇中的溶解性的作用,从而增加其催化活性;载体对K2CO3催化剂活性有明显影响,以煤质柱状活性炭为载体的催化剂活性最高,且负载后的催化剂反应条件更温和。     

碳酸二甲酯-甲醇-邻二甲苯三元体系汽液相平衡研究

测定了DMC—CH3OH,DMC—C8H10,CH3OH—C8H10二元体系汽液平衡实验数据,利用二元体系的汽液平衡数据,运用C语言用Wilson状态方程模拟推算了碳酸二甲酯-甲醇-邻二甲苯三元体系在常压下的汽液平衡,为建立精馏分离碳酸二甲酯-甲醇二元共沸体系的数学模型提供了必要的VLE数据。     

CO2-CH4混合气体水合物相平衡实验研究

CO2置换开采天然气水合物是集温室气体储存和天然气水合物开采于一体的方法,已引起研究者的广泛关注。针对CO2置换法技术,本文利用建立的气体水合物相平衡测试装置,在273.7K～284.2K温度范围内测试了3组CO2-CH4混合气体的三相共存（H-V-LW）和较高四相点Q2（H-LW-LC-V）的相平衡特性。研究结果给出了实验温度范围内混合气体水合物随甲烷含量提高的相平衡压力特性,以及该混合气体水合物体系较高四相点Q2（H-LW-LC-V）稳定区的边界和混合气体水合物融化开始和融化结束时的Q2点。数据表明,混合气体中随着甲烷相对二氧化碳浓度的增加,Q2点随之增加,四相共存状态压力和温度范围也随着扩大。     

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天然气中常含有少量CO2气体。文章介绍低温下小分子量烃类混合物中CO2饱和浓度的理论计算方法,在计算过程中运用了能够准确反映气液相平衡的热力学状态方程。对于其它溶解物,只要可以准确得出固－气相平衡压力关系,该方法仍可实用。最后,将运用本方法所得计算结果与一些已有实验结果进行了比较,证明本方法用于LNG、LPG可以得到很好的结果。     

含盐和甲醇体系中气体水合物的相平衡研究：Ⅰ.平衡生成条件 …

在温度２６０．８￣２８１．５Ｋ和压力０．７８￣１１．１８ＭＰａ下，采用“压下搜索法”在自行设计和组建的实验装置上测定了一个合成天然气在含盐以及含盐和甲醇水溶液体系的水合物平衡生成条件，共１１个体系７２个数据点。结果表明，无论对于单盐或多盐水溶液体系，甲醇对天然气水合物的生成均有显著的抑制作用；当溶液中甲醇增加至２０％（质量）时，ＫＣｌ的抑制作用强于ＣａＣｌ２。     

水合物法分离CH4-C2H6-H2O体系的相平衡研究

本文进行了水合物法分离CH4-C2H6体系的气体-水合物相平衡实验研究,考察了水合物促进剂四氢呋喃（THF）和十二烷基硫酸钠（SDS）对水合物法分离CH4-C2H6体系的影响,通过改变原料气的组成,做出了水合物法分离CH4-C2H6体系的T-P-x—y曲线图。研究发现．在纯水体系中采用水合物法分离CH4-C2H6混合气体,分离效果不明显;当在水溶液中加入水合物促进剂四氢呋喃（THF）和十二烷基硫酸钠（SDS）后,水合物法可以很好地实现CH4-C2H2体系的分离,解决了采用传统深冷分离方法分离CH4-C2H6体系时,由于CH1、C2H6沸点较低而造成能耗较高的问题,开发出了一种新型分离CH4-：C2H6;体系的方法,所得结果对水合物法分离（CH4-C2H6）技术的开发与应用具有重要的指导意义。     

CO2含量对天然气高压物性及烃-水相平衡的影响

以实验测试为基础进行富含CO₂天然气藏的高压物性特征分析,同时按照中国石油行业标准“SY/T 6434-2000天然气藏流体物性分析方法”,建立适用于含CO₂天然气高压物性的测试方法,运用室内物理模拟方法给出在天然气藏中不同含量的CO₂对天然气物性的影响效果评价,并进行相态分析研究;通过对不考虑地层水和考虑地层水的含CO₂天然气进行PVT相态分析(单次闪蒸、等组成膨胀等)实验测试,全面地分析了含CO₂天然气藏地层流体相态变化特征,获得含CO₂天然气的偏差系数、体积系数、密度和压缩系数等物性参数变化规律,结果表明:CO₂-烃-水体系的相态特征很大程度上受到CO₂含量的影响;另外文章对在不同状态方程模型下,富含CO₂天然气偏差因子的计算精确度进行对比分析表明:PR状态方程精确度高,相对平均误差不超过1%,适应性好。     

夹带剂对CO_2-C_2H_5OH-H_2O体系相平衡的影响

用汽相循环法,在夹带剂乙二醇或丙三醇的存在下,测定了313.2K,10MPa下CO_2-C_2H_5OH-H_2O-夹带剂的四元相平衡数据,对试验数据进行了处理分析。结果表明:10mol％的夹带剂加入原料中,可提高二氧化碳对乙醇-水的分离选择性,但是还不能打破乙醇-水的常压恒沸点。     

Experimental and modeling asphaltene precipitation in presence of DBSA using PC-SAFT EOS

Asphaltene precipitation and subsequent deposition in production tubing and topside facilities present significant cost penalties to crude oil production. Therefore, it is highly desirable to predict their phase behavior and the efficiency of dispersants in preventing or delaying deposition. Very few studies have been carried out on the molecular interactions between asphaltenes and different dispersants. As a result, the mechanisms by which dispersants stabilize asphaltenes are still open to discussion. The authors introduced a new method to characterize asphaltenes in perturbed chain statistical association fluid theory equation of state (EOS; perturbed-chain statistical association fluid theory EOS [PC-SAFT-EOS]) and correctly model the effect of dodecyl benzene sulfonic acid (DBSA) dispersant on the thermodynamic behavior of asphaltenes. Using the filtration method the effect of the ionic dispersant (DBSA) on asphaltene precipitation for different concentrations of n-heptane was measured experimentally, then modeled through PC-SAFT EOS. In the approach only the hard-chain and the dispersion terms are taken into consideration, and PC-SAFT parameters were calculated based on Gonzales et al. (2007 Gonzalez, D. L., Hirasaki, G. J., Creek, J., and Chapman, W. G. (2007). Modeling of asphaltene precipitation due to changes in composition using the perturbed chain statistical associating fluid theory equation of state. Energy Fuels 21:1231–1242.[Crossref], [Web of Science ®] , [Google Scholar]) based on molecular weight (Mw) and aromaticity factor (γ). Additionally, the model could correctly predict the amount of asphaltene precipitation upon addition of DBSA dispersant.     

Fluid phase equilibrium prediction of acid gas solubility in imidazolium-based ionic liquids with the Peng-Robinson and the PC-SAFT models

In this research, the solubility of two single gases, hydrogen sulfide and carbon dioxide, in the sixteen ionic liquids ([emim][eFAP], [emim][EtSO₄], [emim][OTf], [emim][Tf₂N], [bmim][BF₄], [bmim][OTf], [bmim][PF₆], [bmim][Tf₂N], [hmim][PF₆], [hmim][Tf₂N], [omim][PF₆], [omim][Tf₂N], [HOemim][BF₄], [HOemim][OTf], [HOemim][PF₆] and [HOemim][Tf₂N]) are modeled using the Peng-Robinson and the PC-SAFT equations of state. For the ionic liquids, the pure component parameters of the PC-SAFT EoS have been obtained by the predictions of the model to both of experimental H₂S and CO₂ solubility data in ionic liquids as well as experimental liquid density data. Also, the critical properties and acentric factor of the ionic liquids were estimated using the modified Lydersen-Joback-Reid method. In the next step, the temperature-independent interaction parameters between the ionic liquids and the gases for both equations of state were calculated by fitting to the experimental VLE data and the obtained results were analyzed. In most of the studied binary systems, the percent average absolute deviation was lower than 10% that shows good agreement between the experimental and predicted values.     

Prediction of asphaltene precipitation from n-alkane diluted crude oil by using PC-SAFT equation of state

The precipitation tendency of heavy organics such as asphaltene has posed great challenges for petroleum industry, and thus study of asphaltene precipitation amount and formation conditions seems to be necessary. One of the most common approaches for prediction of asphaltene precipitation is using thermodynamic models. In this study a PC-SAFT equation of state (EOS) is used to predict asphaltene precipitation in two Iranian dead oil samples. Asphaltene content is obtained by filtration method of the oil samples diluted with specific concentrations of different normal alkanes. Also liquid-liquid equilibrium is used for characterization of oil sample into one heavy phase (asphaltene) and another light phase (saturates, aromatics, and resin). Calculations show that the developed model is highly sensitive to interaction parameter between oil fractions. Prediction results were improved due to using Chueh-Prausnitz equation. The results indicate good potential of PC-SAFT EOS in the prediction of asphaltene precipitation in crude oil samples diluted with different normal alkanes. The model error is <5% and the model precision is increased by reducing the number of normal alkane carbons.