气-液-液-水合物多相平衡闪蒸的新算法

有水合物存在的多相闪蒸计算对于水合物法分离技术非常重要.提出了一个进行气-液-液-水合物四相闪蒸计算的新算法.其中气-液（富烃相）-液（富水相）三相平衡闪蒸计算采用Patel-Teja状态方程,Chen-Guo水合物模型用于气相与水合物相平衡的计算.此算法避免了求解复杂的方程组,因此使计算简单化.通过气体与纯水体系和有抑制剂体系的计算检验表明,此算法有很好的计算稳定性.     

费托合成浆态床反应器模型研究进展

基于文献中的热态研究成果,总结了费托合成浆态床反应器模型的研究进展,并根据流动状态的理想性、气泡分类、模型的维度和模型研究方法对相关的研究工作进行了梳理和总结. 经过分析归纳,认为费托合成浆态床反应器模型的复杂度日益提高,与实际反应情况越来越接近,结合CFD技术,以多维度、多气泡群、非理想流动为特征的模型是未来研究工作的趋势. 对模型建立过程中必需的气液平衡和产物分布计算方法进行了系统的调研与分析,认为Henry定律适于合成气溶解度计算,而状态方程适于产物分布计算.     

二氧化碳在二甲基甲酰胺及其水溶液中溶解度的测定

采用低压容量法气液平衡测定仪测定了不同温度下CO_2在纯水、纯二甲基甲酰胺(DMF)及其混合溶剂中的溶解度,并计算了Henry常数和Ostwald系数。该装置适用于恒温(室温以上)常压下的气体在纯溶剂和混合溶剂中的气液平衡数据测定。     

气体在含盐非水溶液中的溶解度——CO_2-CuAlCl_4·(C_6H_5CH_3)_n体系的气-液平衡

本文提出了拟二元模型和状态方程联用的方法,计算加压情况下CO_2-CuAlCl_4·(C_6H_5CH_3)_n体系的气-液平衡数据.选用拟一元模型得到的CuAlCl_4·(C_6H_5CH_3)_n的表观临界参数和表观偏心因子作为状态方程中含盐非水溶液的特征参数.由实测的气-液平衡数据拟合了状态方程中的二元可调参数.考察了两种混合规则对计算精度的影响,发现修正混合规则后的P-R方程比原始的P-R方程具有更高的关联精度.计算表明,能用拟二元模型和状态方程来描述该体系的气-液平衡关系.     

固-液平衡计算的进展

本文介绍了如何由气—液平衡、混合热、状态方程以及由基团贡献法,预计固—液平衡关系。文中所述及的方法,适用于简单低共熔体系。     

H_2S-H_2O体系汽液平衡的研究

用带压弹式静态法汽液平衡装置测定了H_2S-H_2O体系在37.80℃～104.3℃,2～17大气压下的液相平衡数据,提出了在0～104℃和中压范围内该体系的汽液平衡数据可用Henry和Raoult定律进行关联,计算结果分别与实测数据和文献值作了比较。提出了适用于0～104℃下硫化氢的Henry常数与温度的关联式。     

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。     

用Newton-Raphson法拟合水-乙醇气液平衡体系的Wilson方程参数

利用Newton-Raphson法拟合了气-液平衡计算中最困难的二元含水体系(水-乙醇体系)气液平衡组成的Wilson方程参数.结果表明,该方法简单,计算精度高,有理论和实际意义.在全部浓度范围内与实验值比较,结果说明,Wilson方程能很好地应用于该体系,计算结果令人满意.     

UNIFAC基团贡献法研究及应用进展

UNIFAC 基团贡献法是推箅组分活度系数应用最广泛的模型之一.介绍了UNIFAC基团贡献法的研究进展,分析了UNIFAC模型在气液平衡(气体溶解度、纯组分的蒸汽压、典型气液平衡预测)、液液平衡(液体混合物的表面张力、萃取精馏体系、聚合物溶液粘度的推算、典型液液平衡预测)、固液平衡(同分异构体的平衡体系、固体溶解度的计算)体系的应用领域及其局限性,并针对UNIFAC基团贡献法存在的问题,提出UNIFAC基团贡献法的研究方向和具体的研究内容.     

二氧化碳和丙烯酸酯体系的相平衡数据

利用可变体积高压釜,在313K、333K、353K和373K下,测定了二氧化碳分别与丙烯酸甲酯和丙烯酸丙酯二元体系的气液两相平衡数据。应用Peng-Robinson(P-R)状态方程对实验数据进行计算,计算结果与实验结果具有较高的一致性。本文还计算得到了不同温度和压力下二氧化碳在丙烯酸酯溶解过程中的Henry系数、偏摩尔焓变和偏摩尔熵变等热力学数据。     

The Performance of EOS Models in the Prediction of Vapor-Liquid Equilibria in Asymmetric Natural Gas Mixtures

The aim of this work is to apply cubic equations of state (EOS) to vapor-liquid equilibria calculations of gas- heavy hydrocarbon systems, which are asymmetric in molecular size and are usually found in natural gases. Investigation has been done to test the validity of the original PSRK and the cubic simplified perturbed hard-chain (CSPHC) models for global phase diagrams. The calculation results show that both equations overpredict vapor pressure in the near critical region. In the prediction of the solubilities of high molecular weight (MW) hydrocarbons in the natural gas, the PSRK model gives good agreement for the dew point pressure-vapor composition diagrams. Adjustment of the pure component parameters of the CSPHC EOS for heavy components to fit the vapor-liquid equilibrium (VLE) data has been proved to give significant promoting in prediction accuracy. However, further improvement of a van der Waals EOS, such as SRK, PT and DG models for the asymmetric systems by adjusting the three pure component properties, Tc, pc and ω, did not achieve satisfactory results for heavy components.     

超临界甲醇＋甘油＋脂肪酸甲酯体系气液相平衡算法的改进

提出了一个使用PR状态方程计算超临界甲醇＋甘油＋脂肪酸甲酯体系气液平衡的快速算法。基于威尔逊关联式,利用单纯性法优化了相平衡常数的初始值;提出了一个判断是否处于气液两相区域的有效判断方法。与常规多元相平衡算法相比,新方法显著地减少了迭代次数,并拓展了算法的应用范围,甚至可以计算接近于单相区的气液平衡问题。     

AN NEW GROUP-CONTRIBUTION EQUATION OF STATE AND ITS APPLICATION TO PHASE EQUILIBRIUM CALCULATIONS(Ⅲ)Application to Liquid-Liquid Equilibria

Based on the group interaction parameters determined from binary VLE data,the VDW-GC EOS developedin Part I~[13] is extended to binary and multicomponent liquid-liquid equilibrium calculations.Equilibrium phasecompositions and the temperature effects on LLE can be predicted with reasonable accuracy.     

一个非局部组成型活度系数方程

根据前文提出的液体混合的通用Gibbs自由能模型,导得了一个两参数非局部组成型活度系数方程.它适用于各种小分子液体混合物和高分子溶液,并能由二元参数预测多元系汽液平衡.对小分子液体混合物的泡点计算结果表明,除了醇/烃系统外,计算准确度不逊于局部组成型活度系数方程.它对高分子溶液的适用性则明显地优于UNIQUAC等方程.     

一个非局部组成型活度系数方程

根据前文提出的液体混合的通用Gibbs自由能模型,导得了一个两参数非局部组成型活度系数方程.它适用于各种小分子液体混合物和高分子溶液,并能由二元参数预测多元系汽液平衡.对小分子液体混合物的泡点计算结果表明,除了醇/烃系统外,计算准确度不逊于局部组成型活度系数方程.它对高分子溶液的适用性则明显地优于UNIQUAC等方程.     

Vapor-liquid equilibrium correlations for systems containing amines using a lattice fluid equation of state with hydrogen bonding

The nonrandom lattice equation of state with hydrogen bonding (NLF-HB EOS) was examined for the correlation of vapor-liquid equilibria (VLE) for binary amine and hydrocarbon mixture at various temperatures. For these mixtures, the consideration of hydrogen bondings in the lattice equation of state clearly improves the prediction for VLE. The amines were divided into four groups due to the different strength of the hydrogen bonding. For all groups, different hydrogen bonding parameters were obtained and evaluated. The effects of varying hydrogen bonding energies for NLF-HB EOS are discussed. For systems containing lower amines, the NLF-HB EOS showed excellent agreement with the experimental data. For the correlation of systems containing tertiary amine molecules, binary interaction parameter had to be involved instead of hydrogen bonding parameters.     

Taking advantage of available cubic equations of state

All available simple cubic equations of state (EOS) are developed for specific representations. An effort has been made to take advantage of these existing equations for binary vapor-liquid equilibrium (VLE) as well as density calculations by assigning different EOS to different components of the mixture under consideration. A four-parameter cubic equation was used for combining the equations in the calculation. The effect of substance-dependent Ω_ac on vapor-liquid equilibrium calculations was further investigated, using two sets of mixing rules. A criterion for selection of equations for VLE calculation by means of the proposed approach was suggested. The improvement in the prediction of liquid volumes for binary mixtures based on the fitting of pure component liquid volumes was very satisfactory.     

Liquid–liquid equilibrium correlations using lattice fluid equation of state with hydrogen bonding

The nonrandom lattice equation of state with hydrogen bonding (NLF-HB EOS) was examined for the correlation of liquid–liquid equilibria (LLE) for binary alcohol and hydrocarbon mixture in a wide pressure range. For hydrocarbon + alcohol mixtures the consideration of a hydrogen-bonding term in the lattice equation of state clearly improves the prediction for vapor–liquid equilibrium (VLE) as shown in previous works, but the prediction of LLE is still in question. In this paper, LLE data for alcohols (methanol and ethanol) + hydrocarbons (n-hexane to n-hexadecane) were correlated by NLF-HB EOS and results were compared with a cubic equation of state (Peng–Robinson EOS with the T–K Wilson based G^E model). Both equations of state showed similar degree of accuracies but with different number of adjustable parameters. The Peng–Robinson EOS based approach requires six temperature dependent coefficients for accurate calculation whereas NLF-HB EOS requires only two temperature dependent coefficients. The effects of varying hydrogen-bonding energies for NLF-HB EOS are discussed.     

Heterogeneous modeling for fixed-bed Fischer–Tropsch synthesis: Reactor model and its applications

A comprehensive one-dimensional heterogeneous reactor model is developed to simulate the performance of fixed-bed Fischer–Tropsch reactors for hydrocarbon production. The detailed mechanistic kinetics is combined into the reactor model along with considering the fact that the catalyst pores are filled with liquid wax under realistic conditions. The equilibrium between the gases in the bulk and the wax in the catalyst pores is correlated by using a modified SRK equation of state (MSRK EOS). The model is solved by using Gear method to integrate the reactor model with the embedded pellet model discretized by orthogonal collocation on finite elements. The validity of the reactor model is tested against the measured data from different-scale demonstration processes. Satisfactory agreements between model predictions and experiment results are obtained. Detailed numerical simulations are performed to investigate the effect of major process parameters on the reaction behavior of fixed-bed FTS systems with recycle operation.