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J.
Thomas McKinnon
Professor
BS
Cornell University
PhD Massachusetts Institute of Technology
Aromatic oxidation; pyrolysis chemistry, water mist fire suppression, chemical reaction engineering software development
Research
Description
Our
research is in engineering applications of high temperature, gas phase
chemical reactions. Most of our work is directly or peripherally related
to combustion processes.
Aromatics oxidation and molecular weight growth:Aromatics comprise a sizeable fraction of many fuels (e.g., approx. 35% of gasoline) and are formed in combustion processes even they are not originally present. They are important for their role in particulate (soot) formation in flames as well as their role in forming toxic polycyclic aromatic molecules (e.g., benzo(a)pyrene). In our lab we approach this problem experimentally and numerically. In our experiments, premixed, flat flames are probed with our molecular beam/mass spectrometer to obtain species profiles of stable molecules and free radicals. We also model aromatics combustion at two levels. First, using elementary reaction mechanisms we can simulate the flame on the computer in order to discern the important chemical steps. Second, when elementary reaction rates are not well known, we use quantum molecular orbital methods, such as RRKM, to estimate them.
Pyrolysis chemistry:Pyrolysis processes occur extensively in industry and in nature. Novel pyrolysis processes have been proposed for treating hazardous waste as well as mixed (radioactive waste contaminated with hazardous chemicals). We have ongoing research programs on pyrolysis of dichloroethane and cellulose. The former case is the industrial method for vinyl chloride production. In the latter case we are interested in the formation of toxic aromatic compounds from biomass pyrolysis.
Water
mist fire suppression:The manufacture of bromine-based chemical fire
suppression agents (e.g., halons) has been banned by international protocols
due to their ozone-destroying potential.
The lack of an acceptable chemical alternative has led to increasing
interest in fine water mist fire suppression systems for protection of
areas that previously had used halons š computer rooms, aircraft, ships,
historic buildings, etc. Water
mist fire suppression systems can extinguish fires with about an order
of magnitude less water than a conventional sprinkler system.
Our research is directed at understanding the detailed interaction
of the water mist with the flame front.
Our experimental program is centered around microgravity tests
to be carried out on the Space Shuttle (STS-107).
Removing gravity eliminates settling of the mist and buoyancy of
the flame, allowing more insights to made from the experimental results. We have a parallel numerical modeling effort
underway that allows us to computationally decouple such effects as the
heat of vaporization, dilution, heat capacity, and surface-mediated radical
recombination.
Chemical
reaction engineering software development: A wide variety of
software tools exist to aid in modeling and understanding gas-phase chemical
process operations. These tools include chemical reactor simulators that
allow the inclusion of thousands of elementary reactions, thermodynamic
property estimation tools (e.g., group additivity, molecular mechanics,
electronic structure), and rate constant estimation tools (e.g., RRKM). Despite the availability and power of these,
and other reaction engineering tools, we live in an electronic Tower of
Babel; the tools have incompatible data input and output formats which
makes integration of techniques difficult at best.
We, along with ten other university, industry, and national laboratory
collaborators, are developing the Computational
Chemistry and Reaction Engineering Workbench a software product that
with allow seamless integration of a wide variety of tools to facilitate
chemical reactor modeling.
1992 NSF Young Investigator Award
Contact
Information
J. Thomas McKinnon
423 Alderson Hall
Chemical Engineering Department
Colorado School of Mines
Golden, CO 80401
Office: (303) 273-3098
FAX: (303) 273-3730
jmckinno@mines.edu
