Xiaodong Liang

A Systematic Methodology for Property Model-Based Chemical Substitution from Chemical-based Products

Abstract In this paper, a general model-based methodology for chemical substitution, which takes into account different problem definitions depending on the objective for substitution, is presented. The associated property models and modeling tools are also described. The application of the methodology is shown through an example on substitution of a chemical from a chemical-based product. It is about finding a substitute for a non-biodegradable surfactant used in products from the cosmetics and personal care sector. Amino acid based surfactants are found to be particularly viable substitute candidates. However, this example requires the development of a set of new group contribution-based models for a number of useful properties of amino acids, which are also presented. Besides this, several other known substitution problems are solved using the developed methodology.

Energy Efficient Design of Ionic Liquid based Gas Separation Processes

Abstract Gas separation processes are among the most important operations in the oil and gas related industries. The most common separation technology applied is distillation, which consumes large amounts of energy. Because of the good stability, non-volatility, tunable viscosity and designable properties, ionic liquids (ILs) are regarded as novel potential solvents and alternative media for gas absorption. Therefore, a strategy for hybrid gas separation process synthesis where distillation and IL-based absorption are employed for energy efficient gas processing has been developed. In this work, a three-stage methodology proposed for hybrid gas separation process design and evaluation is proposed: IL screening, where a systematic screening method together with a database tool is established to identify suitable ILs; process design, where the important design issues (amounts of solvent needed, operating temperatures and pressures, evaporation conditions, etc.) are determined; process simulation and evaluation, where the final separation process results are concluded.

A General Model-based Methodology for Chemical Substitution

Abstract The paper presents a general methodology for model-based chemical substitution, which considers different problem definitions depending on the objective for substitution. The developed methodology makes use of validated property models and modeling tools, thus avoiding the resource intensive and time-consuming experimental procedures during the initial stages. First, data and the property models are used to identify the chemicals present in a product that do not satisfy the regulatory property (EH&S: environmental, health and safety) bounds. Next, candidate molecules are generated and evaluated in order to identify those that can serve as safe substitutes and which are compatible with the original product or process function. Practical examples on substitution of chemicals used in processes and products in various sectors like automobiles, coatings and solvents, and polymers have been solved (Jhamb et al., 2017). In this paper we illustrate the methodology with an example concerning the substitution of a solvent, which is toxic to the aquatic environment (Eurochlor.org, 2015) but commonly used for dissolution of ultrahigh molecular weight - polyethylene (UHMW-PE), in its gel spinning process.

Energy Efficient Hybrid Gas Separation with Ionic Liquids

Shale gas, like natural gas, contains H2, CO2, CH4 and that light hydrocarbon gases needs processing to separate the gases for conversion to higher value products. Currently, distillation based separation is employed, which is energy intensive. Hybrid gas separation processes, combining absorption and membranes together with distillation require less energy and have attracted much attention. With the property of non-volatility and good stability, ionic liquids (ILs) have been considered as new potential solvents for the absorption step. However, the enormous number of potential ILs that can be synthesized makes it a challenging task to search for the best one for a specific hybrid separation. In order to solve this problem, a systematic screening model for ILs is established by considering the needed properties for gas absorption process design. Rigorous thermodynamic model of IL-absorbed gas systems is established for process design-analysis. A strategy for hybrid gas separation process synthesis where distillation and IL-based absorption are employed for energy efficient gas processing is developed and its application is highlighted for a model shale gas processing case study.