Grantee Research Project Results
2002 Progress Report: Engineering Environmentally Benign Solvent Systems
EPA Grant Number: R828169Title: Engineering Environmentally Benign Solvent Systems
Investigators: Broadbelt, Linda J. , Zhang, Qizhi , Khan, Shumaila
Institution: Northwestern University
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 2000 through August 31, 2002
Project Period Covered by this Report: September 1, 2001 through August 31, 2002
Project Amount: $223,199
RFA: Exploratory Research - Engineering, Chemistry, and Physics) (1999) RFA Text | Recipients Lists
Research Category: Safer Chemicals , Water , Land and Waste Management , Air
Objective:
This research project will develop the capability to construct complex chemical mechanisms for broad compound classes to allow the impact of an engineered solvent system on ozone formation to be probed. Ambient ozone in urban and regional air pollution represents one of the country's most pervasive and stubborn environmental problems. Strategies for pollution prevention in the chemical industry aimed at reducing the formation of ground level ozone have focused on identification of fugitive emissions, reduction of process chemicals, and elimination of organic solvents from product formulations. Less attention has been paid to engineering organic solvent systems with both the desired properties for a particular application and the environmental implications of the emissions in mind. Our inability to predict the ozone formation potential of a given solvent formulation rapidly and reliably is a limitation to effectively implementing this pollution prevention strategy. Because the number of experiments required to probe the impact of a given solvent formulation on ozone formation is prohibitive, prediction using detailed kinetic modeling is an attractive alternative that has been shown to successfully capture experimentally observed behavior. However, uncertainties remain in the application of chemical mechanisms over a wide range of conditions and to higher molecular weight species, aromatic compounds, and reaction of carbonyls, limiting their predictive capability.
This research project builds on our capability to generate complex reaction mechanisms via the computer. This automated model construction tool eliminates the tedious manual effort required to construct detailed kinetic models, links the reaction with computational quantum chemistry techniques and other theoretical approaches for estimating rate constants that are unavailable experimentally, and provides a solution capability.
Progress Summary:
We have developed the core algorithms for computer generation of reaction mechanisms for ozone formation. Specifically, we have identified the key reaction families that govern ozone formation and also have formulated reaction operators that we implemented in the software. These reaction families have been programmed into the mechanism generation software. To determine whether it was necessary to implement the reverse reactions of all the reaction families, order of magnitude estimates and error bounds have been determined for ratios of forward to reverse rates. One main emphasis of the past year has been to develop kinetic correlations for the different reaction families, allowing us to estimate unknown rate constants. We also have developed the interfaces between the mechanism generation algorithms and programs for estimating thermochemical properties and rate constants.
The progress to date on developing rate constant estimation routines for the different reaction families relevant to atmospheric chemistry is summarized in a manuscript that will be submitted to Atmospheric Environment shortly. (We can provide a hardcopy of this draft manuscript upon request.) We are conducting quantum chemical calculations to estimate missing groups from our thermodynamic group additivity database; these calculations will be completed soon. Our work in this area also will be presented at the upcoming meeting of the American Institute of Chemical Engineers in November via an oral presentation.
The work to develop the interface between the mechanism generation algorithms and the methods for calculating rate constants and thermodynamic properties is complete. If required, we will provide a hardcopy guide to the different executables that are available. We also have created a stand-alone version of the property query software that will be made available via our Web site.
Future Activities:
Because the rate constant estimation routines and the interface for querying rate constants and thermodynamic properties are in place, we can concentrate on generating mechanisms for ethane, acetone, methyl ethyl ketone, and mixtures of acetone and methyl ethyl ketone. This is the final main goal outlined in the original proposal. We anticipate that the mechanism growth will be explosive; therefore, we will concentrate our efforts on manipulating the reaction rules and using the rate-based criterion to control the generation.
Journal Articles:
No journal articles submitted with this report: View all 13 publications for this projectSupplemental Keywords:
air, ozone, global climate, tropospheric, volatile organic compound, VOC, solvents, organics, effluent, alternatives, environmentally conscious manufacturing, engineering, modeling., RFA, Scientific Discipline, Air, Toxics, INTERNATIONAL COOPERATION, Sustainable Industry/Business, air toxics, Environmental Chemistry, cleaner production/pollution prevention, VOCs, tropospheric ozone, Engineering, Chemistry, & Physics, Chemicals Management, air quality standards, urban air, exposure and effects, stratospheric ozone, atmospheric particles, environmentally conscious manufacturing, ozone, chemical composition, chemical kinetics, quantum chemistry, mathematical formulations, pollution dispersion models, urban air , pollution prevention, green chemistry, solventsRelevant Websites:
http://www.chem-eng.northwestern.edu Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.