Workshop on Synchrotron Tools for Studies of Combustion and Energy conversion

Transcription

1 Workshop on Synchrotron Tools for Studies of Combustion and Energy conversion Program Tuesday, Dec 7, 2010 Time Program Presenter Introduktion / Scope of the meeting Marcus Aldén, LU / Jesper Andersen, MAX-lab Technical description of MAX-lab, present and future TBA Break x15 min from poster abstract To be decided Coffee break Synchrotron investigations of fundamental combustion chemistry Craig Taatjes, Sandia, ALS Combustion Study with Synchrotron VUV Photoionization Mass Fei Qi, Hefei Synchrotron Spectrometry Break Photoelectron- and photoionisation mass spectrometry at the SLS Thomas Gerber, PSI, SLS VUV beamline for the determination of thermochemical data x15 min - from poster abstract To be decided Break x15 min - from poster abstract To be decided Dinner Reception and Poster session Wednesday, Dec 8, 2010 Time Program Presenter Some Viewpoints on Spray Measurements Using Synchrotron Mark Linne, CTU Radiation SAXS and NEXAFS as complementary techniques of Laser Light Stefano di Stasio, CNR Scattering for the study of structure and hierarchical clustering of soot nanoparticles Coffee break Particles and Precursors To be decided Discussions Lunch Lab visists, MAX-lab and Combustion Physics Conclusions

2 Combustion Study with Synchrotron VUV Photoionization Mass Spectrometry Fei Qi National Synchrotron Radiation Laboratory, University of Science and Technology of China (KN) Abstract: This presentation reports recent applications of synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) in various research topics of combustion chemistry. The wide tunability of synchrotron photon energy can facilitate the selective identification of isomeric intermediates and near-threshold detection of radicals to avoid fragmentation interference; and the convenient combination of SVUV-PIMS with various laboratory-based combustion approaches demonstrates its universality in combustion studies. Recent experimental achievements have demonstrated the successful applications of this technique in premixed flame, oxidation in jet-stirred reactor, pyrolysis in flow reactor, coflow diffusion flames, catalytic oxidation, plasma diagnostics, and analysis of polycyclic aromatic hydrocarbons (PAHs) and soot. More applications of SVUV-PIMS are expected in near future, not only in combustion studies, but also in other research topics of chemistry such as analytical chemistry, photochemistry, biochemistry, etc. In all applications, combustion intermediates including isomers and radicals can be distinguished unambiguously, which extends our knowledge of intermediate pools and provide more precise targets for quantum chemical calculations of significant reaction channels. The observed mass range covers both small combustion products and large ones such as PAHs with two to five carbonic rings, which present clues to understand molecular growth process from fuel to PAHs and consequently soot in fuel-rich hydrocarbon flames. Furthermore, quantitative analyses of chemical structure are available in most applications, e.g. concentration profiles of flame species versus position in premixed flames, or versus temperature in pyrolysis and oxidation, with objectives to validate current kinetic models and develop new kinetic models. References C. A. Taatjes, N. Hansen, A. McIlroy, J. A. Miller, J. P. Senosiain, S. J. Klippenstein, F. Qi, L. S. Sheng, Y. W. Zhang, T. A. Cool, J. Wang, P. R. Westmoreland, M. E. Law, T. Kasper, K. Kohse-Höinghaus, Enols are common intermediates in hydrocarbon oxidation, Science 308, (2005). F. Qi, R. Yang, B. Yang, C. Q. Huang, L. X. Wei, J. Wang, L. S. Sheng, Y. W. Zhang, Isomeric identification of polycyclic aromatic hydrocarbons formed in combustion with tunable vacuum ultraviolet photoionization, Review of Scientific Instruments 77, (2006). B. Yang, P. Osswald, Y. Y. Li, J. Wang, L. X. Wei, Z. Y. Tian, F. Qi, K. Kohse-Höinghaus, Identification of combustion intermediates in isomeric fuel-rich premixed butanol-oxygen flames at low pressure, Combustion and Flame 148, (2007). Y. Y. Li, F. Qi, Recent Applications of Synchrotron VUV Photoionization Mass Spectrometry: Insight into Combustion Chemistry, Accounts of Chemical Research 43, (2010).

3 T. C. Zhang, L. D. Zhang, X. Hong, K. W. Zhang, F. Qi, T. H. Ye, P. H. Zhao, Y. L. Chen, C. K. Law, An experimental and theoretical study of toluene pyrolysis with tunable synchrotron VUV photoionization and molecular-beam mass spectrometry, Combustion and Flame 156, (2009). F. Battin-Leclerc, O. Herbinet, P.-A. Glaude, R. Fournet, Z. Y. Zhou, L. L. Deng, H. J. Guo, M. F. Xie, F. Qi, Experimental confirmation of the low-temperature oxidation scheme of alkanes, Angewandte Chemie International Edition 49, (2010). K. Kohse-Höinghaus, P. Oßwald, T. A. Cool, T. Kasper, F. Qi, C. K. Westbrook, P. R. Westmoreland, Aspects of the detailed combustion chemistry of biofuels, Angewandte Chemie International Edition 49, (2010).

4 Synchrotron investigations of fundamental combustion chemistry Craig A. Taatjes and David L. Osborn Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, CA USA Abstract: The understanding of complex networks of hydrocarbon reactions, for example in combustion, tropospheric oxidation of organic compounds, or the chemistry of extraterrestrial atmospheres, demands knowledge not only of overall rate coefficients but of the product branching fractions of key reactions. Tunable synchrotron photoionization mass spectrometry permits isomerspecific probing of product branching fractions. In this seminar I will highlight recent advances in the application of synchrotron photoionization methods to measurements of product formation in hydrocarbon radical reactions relevant to combustion. I will discuss the potential of synchrotron photoionization to probe otherwise elusive intermediates of importance to tropospheric and combustion chemistry. Finally, I will investigate possible areas in which new light sources could enable important research in fundamental combustion chemistry.

5 Photoelectron- and photoionisation mass spectrometry at the SLS VUV beamline for the determination of thermochemical data. Thomas Gerber Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland Abstract: Synchrotron radiation in the VUV range is used for the ionization and dissociation of radicals and molecules. The tunability of synchrotron light makes it a versatile tool for the determination of formation enthalpies of ionic and neutral molecular fragments. Our own research aims at the investigations of molecules relevant for combustion. The installed PEPICO endstation, equipped with a differential pumping scheme allowing pressures up to 10 mbar in the interaction region offers external users the possibility to perform studies in many fields of gas-phase dynamics.

6 SAXS and NEXAFS as complementary techniques of Laser Light Scattering for the study of structure and hierarchical clustering of soot nanoparticles. Stefano di Stasio CNR-IM Aerosol & Nanostructures Lab, Istituto Motori, Via Marconi Napoli, Italy Abstract: Laser light scattering techniques are used successfully since many decades to probe combustion flames. The properties of particles coming to existence in the combustion processes are still widely unknown. Optical methods are sensitive to the variations of the refractive index of the sample confined in the measurement volume. One of the limits of the laser experiments is represented by the fact that the complex refractive index does change continuously during the process owing to the change of free electron concentration owing to the progressive decreasing of the ratio between the species hydrogen and carbon. H/C ratio affect also other molecular properties such as, for instance, the mean free path and the orbital hybridization of Carbon which has consequence on the microstructure order at level of crystallinity. The advent of X-ray synchrotron techniques fostered significantly the research in this field. High-brilliance and soft X-rays focussed at hundred micron spot made possible to probing the variations of electron concentration on micron scale of the matter sample. Apart from the concept of a different contrast with respect to laser techniques, X-ray scattering preserves the same advantages of laser light scattering, i.e., to be an in-situ non invasive technique and to be sensitive to the topology of the scattering objects through Fourier inversion of scattered intensity for sufficiently diluted systems. Independently from the shape of the scattered both light and X-ray scattering are able to return the radius of gyration in the Guinier regime and different power exponent in the Power regime, which carry information on the mass and surface, in the fractal and Porod regimes, respectively. Small Angle X-ray Scattering (SAXS) has the advantage vs. Laser Light Scattering (LLS) of a spatial resolution that is one order of magnitude smaller. Moreover SAXS is sensitive to the internal porosity structure of the matter (pore size and density) about which LLS is blind. SAXS can be also used in combination with WAXS to yield information about crystal order. Near Edge Fine Structure Absorption (NEXAFS) is an additional techniques, which is very useful for flame carbon samples to distinguish the level of graphite contents by comparison between the - and - peaks near edge of absorption. In this talk we will give an overview of the potentiality of use the X-ray techniques cited above and further, we will describe some studies on flame soot in which information from LLS has been complemented by the one from SAXS and NEXAFS.

7 Some Viewpoints on Spray Measurements Using Synchrotron Radiation Mark Linne Applied Mechanics, Combustion, Chalmers University of Technology, SE-41296, Gothenburg, Sweden Abstract: Professor Linne will discuss needs for spray research and what could potentially be done using high brightness, collimated x-ray radiation. He will then present and discuss prior spray results from the Advanced Photon Source at Argonne National Labs, and related techniques now in use at the Advanced Light Source at Lawrence Berkeley Labs (both located in the US). Following that, he will speculate on what measurement capabilities could prove useful for a new synchrotron source in Lund.