Time filter

Source Type


Jia L.,University of Lorraine | Le-Brech Y.,University of Lorraine | Shrestha B.,University of Lorraine | Frowein M.B.-V.,Photonion GmbH | And 7 more authors.
Energy and Fuels | Year: 2015

The real-time analysis of volatiles (primary tar) produced during the fast pyrolysis of biomass in a microfluidized bed reactor (MFBR) is achieved by online single photoionization mass spectrometry (SPI-MS). The effect of biomass composition (Douglas fir, oak, and miscanthus), particle shape and size (cylinder, lamella, or powder), bed temperature, and fluidizing gas flow-rate on primary tar composition is studied. Principle component analysis is conducted on the major ions analyzed by SPI-MS to evidence the significant differences between conditions. The variance in obtained SPI-MS spectra reveals the important effect of biomass composition and temperature on volatiles composition. The effect of particle size on volatiles composition is clearly evidenced. Typical pyrolysis regimes are defined according to specific markers which are key chemical compounds to characterize biomass fast pyrolysis. SPI-MS combined with a MFBR is an interesting tool to unravel the effects of biomass composition and of heat and mass transfers on biomass fast pyrolysis processes. © 2015 American Chemical Society. Source

Jia L.,CNRS Reactions and Process Engineering Laboratory | Le Brech Y.,CNRS Reactions and Process Engineering Laboratory | Mauviel G.,CNRS Reactions and Process Engineering Laboratory | Qi F.,Shanghai JiaoTong University | And 7 more authors.
Energy and Fuels | Year: 2016

The online analysis of volatiles from biomass pyrolysis (or gasification or combustion) is interesting because it has the ability to sample the volatiles directly from their reactive environment. The photon ionization (PI) is an efficient and soft ionization method for online analysis of biomass pyrolysis volatiles. Here, we review recent developments conducted in our groups on PI-mass spectrometry (MS) analysis of biomass pyrolysis volatiles by (1) synchrotron light PI-MS and (2) various commercial PI-MS techniques combined with various pyrolysis reactors. The fundamentals of PI-MS applied to biomass tar are briefly presented. The effect of photon energy on mass spectra from biomass volatiles is studied by synchrotron PI-MS. Different sources of PI-MS are then compared on vapors produced from fast pyrolysis in a microfluidized bed, namely, argon electron-beam-pumped excimer light (EBEL) vacuum ultraviolet (VUV) lamp single photon ionization (SPI)-MS (126 nm and 9.8 eV), laser Xe cell-SPI-MS (118 nm and 10.5 eV), laser resonance-enhanced multiphoton ionization (REMPI)-MS (266 nm). The suitability of these different ionization techniques for tar online analysis is discussed. The high potential of PI-MS to unravel the mechanisms of biomass pyrolysis is highlighted by some examples of applications. A VUV lamp SPI-MS has been combined to a fixed bed reactor to study the evolution of chemical markers from lignin, cellulose, and hemicelluloses as functions of biomass types and temperature of pyrolysis. It has also been combined to a microfluidized bed to study the fast pyrolysis of different sizes, shapes, and composition of biomass particles. Principal component analysis of the various MS "fingerprints" reveals interesting markers of some pyrolysis regimes. © 2016 American Chemical Society. Source

Fischer M.,Helmholtz Center Munich | Wohlfahrt S.,Helmholtz Center Munich | Saraji-Bozorgzad M.,Photonion GmbH | Matuschek G.,Helmholtz Center Munich | And 5 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2013

A simultaneous thermogravimetry/differential scanning calorimetry device (STA) was coupled to single photon ionization time of flight mass spectrometry (SPI-TOFMS) for evolved gas analysis (EGA). Thermal resolution with thermogravimetric signals (TG/DTG) is delivered by STA. On-line coupled EGA with SPI-TOFMS retains the thermal information from the STA and substantiates these with correlating mass spectra. The application of vacuum ultraviolet (VUV)-photons (8-12 eV) for soft ionization, allows almost fragment-free ionization. Thus, it becomes possible to interpret mass spectra of complex matrices, like natural products evolving simultaneously several molecules, without an additional separation step. The STA-SPI-TOFMS on-line coupling offers the possibility to track subset mass traces during one STA run. Focusing on material-depended mass traces, differentiation of organic matrices is obvious. In this work two types of research cigarettes, 3R4F and CM6 were used. While the 3R4F cigarette is composed of a blend of different tobacco sorts and different curing methods, the CM6 research cigarette consists of pure flue cured tobacco. The advantages of coupling on-line chemical analysis methods to thermal analysis (TA) are in the context of the achieved thermo-molecular signatures. © 2013 Akadémiai Kiadó, Budapest, Hungary. Source

Fischer M.,Helmholtz Center Munich | Fischer M.,University of Rostock | Wohlfahrt S.,Helmholtz Center Munich | Wohlfahrt S.,University of Rostock | And 7 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2014

The applicability of thermogravimetry (TG) coupled to single photon ionization time-of-flight mass spectrometry (TG-SPI-TOFMS) for evolved gas analysis (EGA) of coffee is demonstrated in this study. Coffee is a chemically well-known complex food product of large scientific and commercial interest. The roasting process of single green coffee beans (Arabica, Robusta) was simulated in the TG-SPI-TOFMS device, and the chemical composition of the evolved roasting gases was monitored on-line. Additionally, roasted and ground coffee powders of different types and brands as well as instant coffee were successfully investigated. For example, the diterpenes cafestol and kahweol can be detected among many other roasting products. These compounds can be of particular interest for quality control of coffee. It is shown that kahweol can be used as a tracer compound to discriminate arabica coffee species from robusta species. © Akadémiai Kiadó, Budapest, Hungary 2014. Source

Czech H.,University of Rostock | Schepler C.,University of Rostock | Klingbeil S.,University of Rostock | Klingbeil S.,Helmholtz Virtual Institute of Complex Molecular Systems in Environmental Health HICE | And 6 more authors.
Journal of Agricultural and Food Chemistry | Year: 2016

Coffee beans of two cultivars, Arabica (Mexico) and Robusta (Vietnam), were roasted in a small-scale drum roaster at different temperature profiles. Evolving volatile compounds out of the roasting off-gas were analyzed by photoionization mass spectrometry at four different wavelengths, either with single-photon ionization (SPI) or resonance-enhanced multiphoton ionization (REMPI). The different analyte selectivities at the four wavelengths and their relevance for the examination of the roasting process were discussed. Furthermore, intensities of observed m/z were grouped by non-negative matrix factorization (NMF) to reveal the temporal evolutions of four roasting phases ("evaporation", "early roast", "late roast", and "overroast") from NMF scores and the corresponding molecular composition from the NMF factor loadings, giving chemically sound results concerning the roasting phases. Finally, linear classifiers were constructed from real mass spectra at maximum NMF scores by linear discriminant analysis to obtain quantities which are simple to measure for real-time analysis of the roasting process. © 2016 American Chemical Society. Source

Discover hidden collaborations