Abstract:
Green process design extends the breadth of the design process to incorporate ecological and sustainability issues early in design. This means extending the traditional process design to include chemical and material selection decisions. This integration poses the challenging problem of discrete and continuous decisions, nonlinear and non-convex models, and uncertainties. This talk presents a computer-aided molecular design approach to greener chemical processes.
Computer-Aided Molecular Design (CAMD) is generally the reverse use of the group contribution method to generate molecules with desirable properties. A group contribution method (GCM) is a technique to estimate and predict thermodynamic and other properties from molecular structures. The optimization approach to CAMD involves combinatorial optimization methods as the resulting problem involves the combinatorial explosion of alternatives. This poses a challenge to optimization techniques. The possibility of obtaining local minima or maxima is very high in such problems as the problem is non-convex. New probabilistic methods like ant colony optimization can circumvent this problem. This talk presents a framework for CAMD for environmentally friendly process design. There are three real-world case studies presented in this work.Since GCMs for vapor-liquid equilibria have been established since the 1970s, I present the CAMD for an industrial case study of solvent selection and solvent recycling. The next two case studies involve solid-liquid systems and we had to establish a new GCM for CAMD. These case studies are related to fracking water and drinking water pollution.
The case studies are detailed below.
Solvents are widely used like dissolving, separating, drying, and cooling agents and as a reaction medium in chemical processing industries; numerous examples of applications can be found in bulk chemical, specialty chemical, and pharmaceutical industries, as well as solvent-based 35 industries (e.g., coating and painting). Solvents are essential in making these chemical processes economically feasible; however, used or waste solvents are a main source of pollution to air, water, and soil if they are not properly controlled. In addition, the generation of waste solvents norms economic performance because the formation of by-products or the loss 40 of raw materials reduces process yield and profit. Increasing public awareness of the environment, health, and safety issues drive governments and regulatory agencies to tighten environmental regulations and boost the number of new regulatory acts and laws. In this talk, I present a separation process for pollution prevention and waste minimization by recycling an in-process solvent (i.e., valuable solvent) from waste solvents with an environmentally benign solvent designed by computer-aided molecular design (CAMD).
Natural gas has become an essential energy resource in the U.S. due to the increasing demand for energy, the high oil prices, and foreign oil independence. The improvement in the drilling technology has allowed the rapid expansion in gas production, especially for unconventional gas such as shale gas. Shale gas is natural gas trapped within fine-grained sedimentary rocks called shale formations. Hydraulic fracturing is used to extract natural gas from these formations. Although natural gas is a cleaner-energy source than coal or oil, there is a lot of controversy due to the environmental impact related to water consumption and treatment. Hydraulic fracturing generates significant volumes of wastewater that contain dissolved chemicals, high content of salts, and significant levels of naturally occurring radioactive material (NORM). Hence, one of this industry's biggest challenges is developing techniques for the prevention, remediation, and appropriate disposal of NORM. This work uses CAMD to generate potential adsorbent candidates according to the properties developed by the new GCMs.Arsenic is a carcinogenic contaminant that pollutes the groundwater (and hence drinking water) due to poor arsenic disposal. Various techniques are used to remove Arsenic, such as oxidation, coagulation-flocculation, membrane filtration, ion exchange, and adsorption, among which adsorption is the most efficient method. Current Arsenic separating agents on the market have a limited adsorption capacity. In this talk, we present novel adsorbents designed using CAMD, which are order-of-magnitude better in the separation of Arsenic and cheaper than the current adsorbents. Experimental verification of these adsorbents will also be presented.
Bio:
Dr. Urmila Diwekar is the President of the Vishwamitra Research, a non-profit research institute that she founded to pursue multidisciplinary research in the areas of Optimization under Uncertainty and Computer-aided Design applied to Energy, Environment, and Sustainability. In chemical engineering, she has worked extensively in the areas of simulation, design, optimization, control, stochastic modeling, and synthesis of chemical processes. She has made major contributions to research on batch distillation, and this work is well recognized. She is the author of more than 190 peer-reviewed research papers, and has given over 420 presentations and seminars, and has chaired numerous sessions in national and international meetings. She wrote the first book on Batch Distillation in 1994, a second edition of the book was out in 2012. Besides publications, she is the author of four commercial software packages. In 2009, she was elected a Fellow of American Institute of Chemical Engineers (AIChE). In October 2011, she received the coveted Cecil Award for Environmental Chemical Engineering from the Environmental Division of AIChE. She is the first woman to receive this national award in its 39-year history. In 2015 she received one of the most prestigious awards of AIChE (an Institute award), the Energy and Sustainability award for leadership in research related to conventional energy, renewable energy, energy-water nexus, carbon capture and environmental control for energy, pollution prevention, and sustainability. In 2018 she received the Clarence Gerhold award (again a national award from the separations division of AIChE) which recognizes an individual’s outstanding contributions in research, development, or in application of separations technology for her pioneering work on batch distillation and green separations.