基于元素和化学键的CPA EoS模型参数估算方法研究

极性和缔合物质是化工流程中的常见物质。结合立方型状态方程和先进缔合项得到的立方加缔合状态方程（CPA EoS）是极性和缔合物质在宽温度和压力范围内相平衡预测的有效方法，但CPA模型参数较少，缺乏通用的参数估算方法，限制了模型的预测能力。基于分子理论的元素和化学键方法可用于CPA模型参数估算。选定用于参数估算的CPA EoS模型后，建立纯物质元素和化学键拆分原则，优化元素和化学键估算纯物质参数的组合规则，用纯物质蒸汽压和液体密度实验数据以逐一优化法回归元素和化学键贡献值，以二元相平衡实验数据回归基团间交互作用参数，并用未参与参数回归的纯物质和二元、三元和多元相平衡实验数据检验模型预测能力。建立以理论模型与实验数据为基础的完善的CPA模型参数通用估算方法，提高CPA模型预测能力，扩大CPA模型应用范围，实现二元、三元、多元体系的相平衡预测，对化工流程模拟计算具有实用价值。

Polar and associating compounds are common fluids in chemical processes. Cubic plus association equation of state (CPA EoS) is proposed by combining the cubic equation of state with advanced association term. CPA EoS is an effective method for the estimation of the phase equilibrium of polar and associating compounds in a wide temperature and pressure range. However, CPA model has fewer parameters of pure compounds and are lack of general parameter estimation methods, which limits its estimation ability. The element and chemical bond method was proposed based on the molecular theory, and it has great capability for the CPA parameter estimation. In this project, after selecting a CPA model for the parameter estimation, the principle for dividing the compound into elements and chemical bonds will be built, and the combining rule of elements and chemical bonds for the compound parameter estimation will be optimized. The contribution value of the element and chemical bond will be fitted with the vapor pressure and liquid density of pure compounds by successive optimization. The interaction parameter will also be optimized with the experiment data of binary phase equilibrium. The estimation ability of the element and chemical bond method will be examined with experiment data of pure compounds, binary, ternary and multiple phase equilibrium that is not fitting the values of element and chemical bond. Based on the theory and experiment data, an effective parameter estimation method for CPA EoS will be built. The established parameter estimation method can improve the predictive capability and extend the application range of CPA EoS. It can be used to estimate the phase equilibrium of binary, ternary, and multiple systems. The parameter estimation method has great practical values for the calculation and simulation of chemical possesses.