GOALI: Combining Discontinuous Molecular Dynamics and Chemical Process Simulation

GOALI：结合不连续分子动力学和化学过程模拟

• 批准号: 0075883
• 负责人: J. Richard Elliott
• 金额: $ 10.99万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0075883&HistoricalAwards=false
• 关键词: GOALI; Combining; Discontinuous; Molecular; Dynamics

ABSTRACTCTS-0075883J. R ElliottIn this two-year exploratory grant prospects will be evaluated for integrating molecular modeling tools with a chemical process simulation package to provide a complete, rigorous, and accurate framework for physical property prediction and correlation. Chemical process simulators are becoming the primary interface for industry chemical knowledge. It has been recently discovered that perturbation theory is much more accurate than previously appreciated, especially for polyatomic molecules. Discontinuous molecular dynamics (DMD) simulation combines with perturbation theory and virial expansion to provide a basis for highly leveraged computational effort in all aspects of molecular modeling. An existing DMD program will run the minimal number of simulations necessary with reasonable speed on low-cost microprocessors. The resulting segmental potential models will act as molecular scale group contributions, analogous to conventional engineering group contribution models. Although these segmental potentials act essentially as first group contributions, higher order effects derived from molecular geometry will be explicitly addressed through the connectivity of the first order groups in the user-designated molecular structure.The initial goal will be to test the transferability of discontinuous potential models for the equilibrium properties of pure fluids and mixtures. A database of fluctuation populations for spheres, dimers, trimers, 6mers, 8mers, and benzene will be developed and be used to develop optimal step potentials for representing experimental values for vapor pressures, density, and internal energy for methane, ethane, n-hexane, n-octane, benzene, water, methanol and ethanol. The transferability of the resulting potentials will be evaluated in terms of the accuracy of predictions for n-butane, n-pentane, n-heptane, n-nonane, and n-decane. For mixtures, the transferability will be evaluated in terms of the accuracy of predictions for ternary mixtures and mixtures like n-propanol+methanol, for which the hydroxyl group in n-propanol was specifically regressed.The second goal will be to implement methods of calculating transport properties like viscosity, thermal conductivity, and diffusivity in addition to the equilibrium and coexistence properties that have been computed in the past. Resulting simulations will probe the extent to which potential models developed solely on the basis of equilibrium properties can be applied to estimating transport properties. It is sought to "dissect" model intermolecular potential functions in the sense of identifying which pieces of the potential correlate most strongly with specific physical properties. Also sought will be broadly applicable mappings of attractive effects on transport properties given DMD simulated properties for reference fluids, by analogy to the perturbation perspective for equilibrium properties. For example, the extent to which the diffusivity of n-decane can be predicted from correlated results for the diffusivity of n-octane and DMD simulations for purely repulsive n-decane will be examined. The work will be performed with collaboration between The University of Akron and ChemStations, Inc. If this exploratory work shows promise, the ultimate goal will be an internet site which clients can access for zero cost up front and relatively low hourly fees varying according to the intensity of the server side computation requested. Services provided will include molecular modeling of transport and equilibrium properties like vapor pressure, activity, water solubility, octanol partition coefficients, viscosity, and the ability to infer knowledge about one property from measurements of other properties through a common molecular model. Within the range of options will be a comprehensive collection of semi-empirical methods with estimates of the accuracy of each property. The scope of this project includes a thorough evaluation of the accuracy all the semi-empirical models and the molecular based models against a database of approximately 1300 compounds. Those evaluations will comprise a significant portion of the work beyond the exploratory phase. Also included in the web-accessible version will be flowsheeting and process simulation based on shortcut unit operation models. The sensitivity of the process capital and production costs to the estimated physical properties will be a menu option. The shortcut model will serve as a precursor for rigorous process simulations directly within a web-based environment.

Abstractcts-0075883J。 R Elliottin将评估这两年的探索性赠款前景，以将分子建模工具与化学过程仿真软件包集成在一起，以提供一个完整，严格且准确的框架，以实现物理属性预测和相关性。 化学过程模拟器已成为行业化学知识的主要界面。 最近发现，扰动理论比以前所欣赏的要准确得多，尤其是对于多原子分子。 不连续的分子动力学（DMD）模拟与扰动理论和病毒扩展相结合，为分子建模各个方面的高度杠杆计算工作提供了基础。 现有的DMD程序将在低成本微处理器上使用合理的速度运行最少的模拟数量。 由此产生的分段潜在模型将充当分子量表组贡献，类似于常规工程组贡献模型。 尽管这些分段电位基本上是作为第一组贡献，但通过用户指定的分子结构中一阶组的连通性明确解决了从分子几何形状得出的高阶效应。最初的目标是测试不连续电位的可转移性纯流体和混合物平衡特性的模型。 将开发用于球体，二聚体，三聚体，6mers，8mer和苯的波动群体的数据库，并用于开发最佳的步长电位，以代表蒸气压，密度，乙烷，乙烷，N-甲基烷，N-己烷的内部能量的实验值，N-辛烷，苯，水，甲醇和乙醇。 将根据N-丁烷，N-戊烷，N-己烷，N-氮烷和N-丹烷的预测准确性评估所得电位的可传递性。 对于混合物，将根据三元混合物和N-propanol+甲醇等三元混合物和混合物的预测准确性评估可转移性，为此，N-丙醇中的羟基被特别回归。第二个目标是实施计算方法除了过去已经计算出的平衡和共存特性外，粘度，导热率和扩散率等传输性能。 所得的模拟将探测仅根据平衡特性开发的潜在模型的程度，可以应用于估计运输特性。 它试图在识别哪些电势与特定物理特性最密切相关的意义上“剖析”模型间分子电位功能。 同样，通过类似于平衡性能的扰动透视图，所寻求的将是针对参考流体的DMD模拟特性的对传输特性的有吸引力效果的广泛适用映射。 例如，将检查N-DECANE的扩散率的扩散率可以从相关的结果中预测到N-辛烷值和DMD模拟对纯粹抑制性N-核心的扩散率的相关结果。 这项工作将与阿克伦大学和Chemstations，Inc.之间的合作进行。请求服务器端计算的强度。 提供的服务将包括传输和平衡特性的分子建模，例如蒸气压，活性，水溶性，辛烷值分配系数，粘度以及通过通用分子模型从其他特性的测量中推断出一种特性的知识的能力。 在选项范围内，将是半经验方法的全面集合，并估计每个属性的准确性。 该项目的范围包括对所有半经验模型的精度和基于分子模型的精度，相对于大约1300种化合物的数据库。 这些评估将包括探索阶段之外的很大一部分工作。 Web访问版本还包括基于快捷单元操作模型的流程图和过程仿真。 过程资本和生产成本对估计物理特性的敏感性将是菜单选项。 快捷方式模型将直接在基于Web的环境中直接作为严格过程模拟的先驱。