(13e) Reduced & Optimized Chemical Kinetic Mechanisms for Energy & Combustion Applications

Reduced & Optimized Chemical Kinetic Mechanisms for Energy & Combustion Applications

Gudiyella, S., Massachusetts Institute of Technology

2^nd Year Postdoctoral Associate

Research Interests:

Solving the current energy/climate problem requires improvements in the energy infrastructure and design of combustion engines. The changing fuel landscape (e.g. natural gas, biomass and reserves of heavy fuel oil) creates the need to improve the feedstock pre-treatment processes, to generate fuels that can be used as â??drop-inâ?? fuels in existing engines. On the other hand, increasingly stringent emission regulations require design changes in the current engines to meet future regulations. The experimental part of my research will focus on developing new chemical processes for producing fuels from heavy crudes and biomass. The modeling part of my research will focus on developing accurate chemical kinetic models for predicting emissions from combustion engines or yield in chemical process industries. The models are built through a combination of experimental work and new fit-for-purpose modeling approaches, for implementation into Computational Fluid Dynamic (CFD) simulations or process simulation software.

The experiments will focus on process improvement to increase the yield of lower molecular weight fuels from upgrading of heavy crudes & biomass feedstocks. An important part of experiments is fuel characterization using gas chromatography (GCxGC-MS) and Nuclear Magnetic Resonance (NMR) techniques. The fuel characterization data will be used develop chemical kinetic models for practical fuels (diesel, gasoline, jet fuel etc.) using the surrogate fuel approach.

The chemical kinetic models will be constructed based on a methodology that exists in literature. For instance, for simpler fuels like jet fuels, the â??comprehensiveâ?? approach is to build a surrogate fuel for the jet fuel and develop detailed chemical kinetic mechanisms for the surrogate fuel. However the size of the mechanism is prohibitive for implementation into CFD simulations or process simulation software without performing extreme reduction. Recent studies have used a â??hybridâ?? approach wherein the fuel decay to major species will be formulated using global steps and the fuel decay is optimized to match the test data. Based on the end-use of the mechanism, global/elementary steps will be included in the mechanism to explain the decay of the major species.

The â??hybridâ?? approach has an advantage of developing compact mechanisms, whereas the â??comprehensiveâ?? approach has an advantage of accurate chemical kinetic description of the fuel. I propose to utilize the best elements of both the â??comprehensiveâ?? and the â??hybridâ?? approach under one framework by building a software called as Global Mechanism Generator (GMG). The software consists of modules to formulate the surrogate fuel (comprehensive approach), to generate a global mechanism and to optimize the mechanism against test data (hybrid approach).

The output of GMG will be a reduced/optimized chemical kinetic models, which can be implemented in CFD or Aspen Plus, to predict emissions from combustion engines or yield in chemical process industries.

Postdoctoral Project: â??Supercritical water upgrading of Arabian Heavy Crude Oilâ?

Under supervision of Prof. William H. Green, Hyot C. Hottel Professor of Chemical Engineering, Massachusetts Institute of Technology (MIT)

PhD Dissertation: â??An experimental and modeling study of the combustion of aromatic surrogate jet fuel componentsâ?

 Under supervision of Prof. Ken Brezinsky, Associate Dean for Research and Graduate Studies in the UIC College of Engineering, Department of Mechanical and Industrial Engineering, University of Illinois at Chicago (UIC)

 Teaching Interests:

My teaching philosophy is based on four aspects. They are exposure to academic and industrial research, use of active learning techniques, highlighting the importance of team-work and encouraging the students to learn beyond the classroom.

Students have to be knowledgeable about how to translate the concepts from a class room setting to an industrial setting. Given this need, my courses will start with the fundamentals and move towards real-world applications. I will expose the students to both academic and industrial research, by discussing relevant research publications and patents. I will also educate the students about the tools which can bridge the gap between academic and industrial research.

My mentoring experience in lab & in professional women's networks has made me realize that the overall development of a student continues beyond the walls of the classroom.

Based on the course being taught, I will also introduce the students to relevant research within the university by organizing an educational trip to the labs or nearby chemical process industries. I will also encourage my students to pursue research-oriented higher degrees, obtain internships and participate in conferences. By participating in conferences, the students will gain a better perspective of the problem-solving approaches adopted by accomplished researchers and also build professional connections.

In summary, I will provide students the required knowledge by designing courses that begin with fundamentals and move towards the â??appliedâ?? direction.

 Research Experience:

As a researcher I am trained in both high pressure, high temperature experimentation and chemical kinetic modeling. My PhD thesis on combustion of jet fuel, enhanced the understanding of soot formation in civil and military aircraft engines, by identifying the species and pathways responsible for the formation of soot. The combustion of jet fuel components was investigated in a High Pressure Single Pulse Shock Tube (HPST). I built detailed chemical kinetic mechanisms for combustion of jet fuel and validated the mechanisms against shock tube experimental data.

After my PhD, I joined General Electric (GE) as a Research Engineer. At GE Global Research, my major focus was developing reduced chemical kinetic mechanisms for fuels such as heavy fuel oil, natural gas and jet fuel. The reduced mechanisms were implemented into CFD to predict the temperature field in the combustor, and emissions and thereby propose combustor design modifications to lower the emissions.

After working for 3 years at GE, I joined the Green Group at MIT as a Postdoctoral Associate. At MIT, my primary project is crude oil upgrading with supercritical water to reduce sulfur impurities and to increase the yield of lower molecular weight fuels. During my postdoc, I expanded my analytical experience by using gas chromatography (GCxGC) and Nuclear Magnetic Resonance (NMR) Spectroscopy for analyzing complex crude oil mixtures.

 Teaching Experience:

I worked as a Teaching Assistant for the Chemical Engineering Laboratory I (CHE 381) and Chemical Engineering Laboratory II (CHE 382) courses at UIC. I taught the undergraduate students how to perform experiments on the distillation column, evaporator and solvent extraction setups etc. I also ensured that the students followed the laboratory health & safety protocols, while handling the chemicals and while working on the experimental setups. During my PhD, I mentored two undergraduate students. During my postdoc, I mentored 3 undergraduate students on the crude oil upgrading project and also work with 3 graduate students on diverse projects. I also completed the Kaufman Teachning Certificate Program in June 2016. The workshop has enabled me to design a course, plan and facilitate a class session.

I also explored external mentoring opportunities. I mentored an undergraduate student during my PhD as a part of UIC Women in Science in Engineering (WISE) Mentoring Program. I was also a mentee in 2016 American Women in Science (AWIS) Mentoring Circles. 

Publications:

S. Mosbach, J. Hyeong Hong, G. P. E. Brownbridge, M. Kraft, S. Gudiyella and K. Brezinsky, â??Bayesian Error Propagation of a Kinetic Model of n-Propylbenzene Oxidation in a Shock Tubeâ?, International Journal of Chemical Kinetics, 46 (2014) 389-404

T. Malewicki, S. Gudiyella and K. Brezinsky, â??Experimental and Modeling Study on the Oxidation of Jet-A and the n-Dodecane/Iso-octane/n-Propylbenzene/1,3,5-Trimethylbenzene Surrogate Fuelâ?, Combustion and Flame 160 (2013) 17-30

S. Gudiyella and K. Brezinsky, â??High Pressure Study of 1,3,5-Trimethylbenzene Oxidationâ?, Combustion and Flame, 159 (2012) 3264-3285

S. Gudiyella and K. Brezinsky, â??High Pressure Study of n-Propylbenzene Oxidationâ?, Combustion and Flame, 159 (2012) 940-958

S. Gudiyella, T. Malewicki, A. Comandini and K. Brezinsky, â??High Pressure Study of m-Xylene Oxidationâ?, Combustion and Flame, 158 (2011) 687-704

S. Gudiyella and K. Brezinsky, â??High Pressure Study of n-Propylbenzene Pyrolysisâ?, Proceedings of the Combustion Institute, 34 (2013) 1767-1774