降凝剂对原油石蜡沉积的影响

在石油开采和输送过程中由于石蜡沉积造成的经济损失每年达数十亿美元。添加化学降凝剂的方法可以避免或减小固相沉积造成的不利影响和危害,因此研究降凝剂对石蜡沉积的影响有非常重要的意义。从流变学和晶体学方面对降凝剂影响原油中的石蜡沉积进行了实验研究。实验数据显示,加剂后原油的析蜡点不变,析蜡峰温向低温方向移动,这是因为降凝剂的加入使得蜡晶的晶格结构由正交型转变为了旋转型,延缓了蜡晶的析出速率,且由于加剂后蜡晶颗粒变大,形状更接近于球形、使得蜡晶聚集体的絮凝能力减弱,原油的低温流动性得到了改善。     

石蜡沉积对储层渗透率的影响研究

油气开采过程中的蜡质、沥青质等有机固相沉积。严重影响着油田的正常生产。固相沉积物不仅堵塞油井、输油管线,而且也给油藏多孔介质造成一系列的伤害。如堵塞油藏孔隙、降低孔隙度和渗透率,改变油藏岩石的润湿性,从而影响原油采收率的提高。本文采用热力学理论建立了液固两相相平衡方程,模拟计算石蜡沉积量对储层孔隙度和渗透率影响,进而求出对油井产能的影响。     

原油管道蜡沉积预测模型研究进展

结合近年来国内外众多学者的蜡沉积研究经验,将各种蜡沉积热力学、动力学以及计算机训练等理论研究方向进行了较为详细的介绍,并对UNIQUAC局部活度系数模型、普适性结蜡模型以及人工神经网络模型等具有代表性的模型进行了比较分析,说明了相应模型的特性和优缺点,并给出了未来蜡沉积研究的发展建议。     

含自缔合流体混合物的分子热力学模型

缔合流体及其混合物的亥氏函数和压缩因子可表示为物理相互作用的贡献和化学缔合作用的贡献两部分之和。前者可采用作者建立的非缔合流体及其混合物的分子热力学模型;作者从分子间相互作用位能函数的粘滞球模型出发,利用统计力学方法确定了混合物中自缔合作用的贡献。模型中分子间的缔合参数完全可由纯物质性质确定,而只在混合物方阱位能参数的计算中引入可调的二元相互作用参数。对于含有一个自缔合组分的二元混合物常压和高压汽液平衡数据的关联结果令人满意。     

原油石蜡结晶与清除的研究进展

本文综述了含蜡原油中石蜡结晶的机理,介绍了国内外的几种清蜡技术,探讨了各种清蜡技术的优缺点,详细分析了清蜡效果的影响因素,提出环保、低成本、高效率、适应性强的新型清蜡剂将是未来清蜡剂的研究方向。     

链状流体的分子热力学模型(Ⅱ)──混合物汽液平衡

实际链状流体混合物的亥氏函数表示为参考流体（硬球链流体混合物）的贡献和由于链节间的方阱位能相互作用的贡献之和．前者直接用作者先前建立的硬球链流体混合物的分子热力学模型计算,不含混合规则;后者采用Alder等人的结果,用vanderWaals单流体理论计算混合物的能量参数.对于不含氢键作用的二元混合物,有一可调相互作用参数,需由实验数据拟合得到．本模型可以满意地关联小分子混合物和高分子溶液的汽液平衡。     

尿素合成的化工计算——热力学模型篇

通过热力学分析和体系简化,分别用PHS状态方程和实验活度系数模型来修正气液两相的非理想行为,以文献报道的实验数据为基础,建立了一个尿素合成反应过程中半经验半理论的热力学模型.该模型的计算值与实验数据和文献数据较一致,可用于尿素合成反应进程中、达化学平衡及高压分解时的气液平衡计算.     

热力学状态方程二元交互作用参数估算模型开发

基于气液平衡理论,建立了热力学状态方程二元交互作用参数估算模型。首先,结合气液平衡理论、状态方程以及相应的混合规则建立气液相平衡数学模型;然后以气相组成误差平方和与压力相对误差平方和之和作为目标函数,并使用计算机编程,利用单纯形法进行优化求解,实现了热力学状态方程二元交互作用参数估算模型的开发;最后,用该模型对5组二元气液平衡体系中的组分二元交互作用参数进行估算,并根据估算出的参数对各体系的气相组成进行预测,结果显示,预测值与实验值的平均相对偏差均小于1％,表明该模型计算结果准确,可应用于气液平衡计算中。     

煤气化过程热力学平衡模型研究进展

煤气化过程机理模型研究对实现煤的高效利用具有重要指导意义。热力学平衡模型在预测煤气化炉合成气组成方面具有简单实用等优点,经过多年的努力,国内外对气化炉的热力学平衡模型研究也取得较大程度进步,本文简要总结了截至到目前煤气化过程热力学平衡模型的研究情况,以期为气化炉设计及生产操作者提供一定参考。     

原油-水系统的三相闪蒸计算及其初值问题

水在油中的溶解度很低,常见的负压闪蒸原油稳定过程及井场的油、水与伴生气分离过程,实际上均为三相闪蒸过程。本文采用比较简单、实用、准确的汽液平衡模型,针对N-R法迭代过程中初值敏感的问题,经研究、计算,找到了油-水物系VLLE计算的初值规律,程序能根据规律自动确定初值,使相应的迭代过程准确、迅速收敛。     

戊二酸在冰醋酸和环己酮、环己醇及五种混合溶剂中的溶解度的测定

By using the laser-monitoring technique, solid-liquid equilibrium data of glutaric acid in cyclohexanol, cyclohexanone, their five mixed solvents and acetic acid were measured within the temperature range from 292.15K to 354.60K by dynamic method. Empirical formula and λh equation were used to correlate the solubilities of glutaric acid in eight solvents. The maximal average relative deviations were 1.15% and 2.20% by using the empirical formula and λh equation to correlate the solubility data. The results showed that the empirical formula and λh model could correlate the solubility data of glutaric acid in eight solvents. In addition, the solubility data of glutaric acid in five mixtures （cyclohexanone＋cyclohexanol） could be predicted with the NRTL equation utilizing the parameters of the binary systems. The total average relative deviation was 3.60%. The results indicate that the NRTL equation could well predict the solubilities of glutaric acid in the mixed solvents of cyclohexanone and cyclohexanol.     

染料残渣焚烧过程中微量元素的形态转化及其迁移分配的预测

The release of heavy metals from the combustion of hazardous wastes is an environmental issue of increasing concern. The species transformation characteristics of toxic heavy metals and their distribution are considered to be a complex problem of mechanism. The behavior of hazardous dyestuff residue is investigated in a tubular furnace under the general condition of hazardous waste pyrolysis and gasfication. Data interpretation has been aided by parallel theoretical study based on a thermodynamic equilibrium model based on the principle of Gibbs free energy minimization. The results show that Ni, Zn, Mn, and Cr are more enriched in dyestuff residue incineration than other heavy metals （Hg, As, and Se） subjected to volatilization. The thermodynamic model calculation is used for explaining the experiment data at 800℃ and analyzing species transformation of heavy metals. These results of species transformation are used to predict the distribution and emission characteristics of trace elements. Although most trace element predictions are validated by the measurements, cautions are in order due to the complexity of incineration systems.     

含蜡原油蜡沉积特性与清蜡周期研究

管道清管作为减小含蜡原油管输安全隐患的主要措施,一直是工程安全研究的重要方面。对原油蜡沉积机理的分析,明确了蜡沉积过程中的主要影响因素,并对个因素的影响效果进行了评价,描述了几种不同清蜡方法的作用效果,研究了含蜡原油管道清蜡周期的影响因素,为管道清管周期的确定提供理论支持。     

2，6-萘二甲酸二甲酯在有机溶剂中溶解度的测定与关联

Solubility of dimethyl-2,6-naphthalene dicarboxylate in acetic acid, N,N-dimethylfonnamide, N,N-dimethyl acetamide, dimethyl sulphoxide, and N-methyl-2-ketopyrrolidine were determined using a dynamic method. The measured systems were correlated by UNIFAC group contribution method. A new main group （aromatic ester, ACCOO） was defined to express the activity coefficients of the aromatic ester. New interaction parameters of the ACCOO group were expressed as the first-order function of temperature and were determined from the experimental data. The calculated results for the new interaction parameters were satisfactory. The measured systems were also correlated with the Wilson and 2-h models, and the results were compared with those of the UNIFAC model.     

SRK状态方程用于聚合物体系的汽液和气液平衡

A simple extension of cubic equations of state （EOS） to polymer systems has been proposed. The Soave-Redlich-Kwong （SRK） EOS was taken as a prototype to be used to describe the PVT behavior of polymer melts in a wide temperature and pressure range. Combined with a modified Huron-Vidal gE-mixing rule it was applied for modeling vapor-liquid equilibria of polymer-solvent solutions and the solubility of supercritical gases in polymer melts. Satisfactory results are obtained.     

Study on wax precipitation characteristics of wax deposit in pipes

Wax deposit properties are a significant concern in pipeline pigging during waxy crude oil transportation. In the present work, the impacts of flow conditions and oil properties on the wax precipitation characteristics of wax deposits are investigated. A flow loop apparatus was developed to conduct wax deposition experiments using four crude oils collected from different field pipes. The differential scanning calorimetry (DSC) technique was employed to observe the wax precipitation characteristics of crude oil and wax deposit. The results show that the wax content and the wax appearance temperature (WAT) of the deposits increase with shear stress and radial temperature gradient, and decrease with radial wax molecule concentration gradient near the pipe wall. The DSC tests on the wax deposits revealed that the deposit wax content is strongly correlated to the oil wax content. Furthermore, an empirical correlation was developed to predict the wax content and the WAT of the wax deposit. Verification of the empirical correlation using the different oils indicated that the average relative error of the wax content prediction and average absolute error of WAT prediction were 13.2% and 3.6°C, respectively.     

二氧化硫对石灰石的直接硫酸盐化作用的热重分析的研究与建模

The direct sulfation of limestone from different sources in Iran was studied in a thermogravimetric analyzer under atmospheric pressure. All limestone samples tested have higher than 97% CaCO3. Experimental conditions were as follows: particle size levels ranging from 1.6μm to 7.8μm, four level reaction temperatures (700°C,750°C, 800°C and 850°C), and two SO2 concentrations (2.4 × 10-3 and 3.2 × 10-3 mol.mol-i). The particle size and temperature showed dominant influences on the rate and level of conversion while the effect of SO2 concentration was weak. The shrinking core model can be used to describe the behavior of the sulfation process. The reaction kinetics and diffusion mechanism are both important in controlling the rate of the process. The two key parameters of the model, chemical rate constant Ks and effective diffusion coefficient Deff were obtained. Model predictions are in good agreement with the experimental data.     

空间质量作用模型预测小分子离子交换平衡

The steric mass-action (SMA) model has been widely reported in the literature for ion-exchange and metal-affinity interaction adsorption equilibrium of biomacromolecules. In this paper, the usefulness of SMA model is analyzed for describing micromolecule ion-exchange equilibrium onto cation exchangers, CM Sephadex C-25 and Streamline SP. Batch adsorption experiments with ephedrine hydrochloride as a model adsorbate are carried out to determine the model parameters, that is, steric factor, characteristic charge and equilibrium constant. The result shows that the SMA model parameters of micromolecule cannot be obtained using the nonlinear least-square fitting method as protein‘s due to the remarkable difference between the molecular mass and dimension of micromolecule and protein. It is considered that the small size of the adsorbates dealt with in this study justifies the neglect of steric hindrances arising from adsorbate bulkiness. Thus, the three-parameter SMA model is reduced to two-parameter one (i.e., steric factor is equal to zero) for describing micromolecule ion-exchange equilibrium. It is found that the equilibrium constant for CM Sephadex C-25 increases with increasing ionic strength, while the equilibrium constant for Streamline SP shows an opposite trend. This is probably due to the remarkable difference between the physicalpro perties of the two adsorbents. Then, the relationship between the equilibrium constant and ionic strength is described by an expression. The computer simulations show that, the theoretical model with the correlation is promising in the prediction of micromolecule adsorption decrease with increasing ionic strength in a wide range of salt concentration.     

高凝油油藏提高采收率技术研究

高凝油油藏在开发过程中,受到流动温度的变化,在地层和近井地带易析蜡和堵塞地层。通过对高凝油性能分析,利用高凝油对温度的敏感性,室内通过化学生热生气体系在油层中生成一定的温度和气体,使得油层温度高于高凝油的凝固温度。保证高凝油具有良好的流动能力,提高了高凝油油藏的开发效果。现场试验结果表明,热化学体系能够达到解堵增产增注的目的,并具有有单井处理用量少,成本低,施工简单等优点,是浅层高凝油油层解堵主要措施之一,为高凝低渗（能）油藏的后继开发指明了新的技术发展思路。