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The aim of this study is to apply a new approach to the quantitative analysis of the formation of gaseous products generated during the thermochemical conversion of wood waste samples of different fineness by using thermogravimetric analysis with mass spectrometry (TGA‐MS). Profiles of the release of gaseous components in the process of thermochemical conversion of wood samples were obtained based on data from the combined use of mass spectrometry and thermogravimetry. The resulting mass spectrometric data were processed according to the proposed methodology and the characteristics of the released gases were noted. The kinetic coefficients of the gases' formation were calculated from the processed data. [ABSTRACT FROM AUTHOR]

This article proposes a method for processing data obtained using the TA-MS complex. To search for calibration coefficients, the method includes solving a quadratic programming problem. To test the method of searching for calibration coefficients, a simulation was done and the inverse problem was solved, and it was found out that the problem was ill-conditioned.

At present, the screw reactor pyrolysis is a promising and rapidly developing technology, because it helps obtain the end product, which is charcoal, tar, and synthesis gas. Additionally, pyrolysis can be considered as a preliminary stage for making the charcoal of the preset conversion for its further gasification when obtaining coal-derived gas. This research aims at establishing relationships between the operational parameters of pyrolysis and obtaining of the charcoal of preset conversion by means of mathematical modeling, full-scale experiment, and instrumental studies. Such comprehensive research ensures the accurate initial data, verification of the model, and optimal parameters for obtaining the product with preset properties as well as for further scaling of the reactor. In terms of design the pyrolyzer represents a recuperative heat exchanger where a mix of stack and recirculation gases is considered as a heat carrier. To prevent sintering of particles the screw transportation of fuel is used. The Comsol Multiphysics Software is used as a simulation environment. Heat exchange in the process of pyrolysis is simulated considering physical properties (porosity, permeability, etc.) of the medium. The constructed calculated mesh consisted of 604 thousand elements of three types (tetrahedrons, prisms and pyramids) and had the minimum size of 0.2 mm.

Stereochemical structure of nine Z-2-(vinylsulfanyl)ethenylselanyl organyl sulfides has been investigated by means of experimental measurements and second-order polarization propagator approach calculations of their 1H-1H, 13C-1H, and 77Se-1H spin-spin coupling constants together with a theoretical conformational analysis performed at the MP2/6-311G** level. All nine compounds were shown to adopt the preferable skewed s-cis conformation of their terminal vinylsulfanyl group, whereas the favorable rotational conformations with respect to the internal rotations around the C-S and C-Se bonds of the internal ethenyl group are both skewed s-trans. Stereochemical trends of 77Se-1H spin-spin coupling constants originating in the geometry of their coupling pathways and the selenium lone pair effect were rationalized in terms of the natural J-coupling analysis within the framework of the natural bond orbital approach. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Stereochemical structure of nine Z-2-(vinylsulfanyl)ethenylselanyl organyl sulfides has been investigated by means of experimental measurements and second-order polarization propagator approach calculations of their (1)H-(1)H, (13)C-(1)H, and (77)Se-(1)H spin-spin coupling constants together with a theoretical conformational analysis performed at the MP2/6-311G** level. All nine compounds were shown to adopt the preferable skewed s-cis conformation of their terminal vinylsulfanyl group, whereas the favorable rotational conformations with respect to the internal rotations around the C-S and C-Se bonds of the internal ethenyl group are both skewed s-trans. Stereochemical trends of (77)Se-(1)H spin-spin coupling constants originating in the geometry of their coupling pathways and the selenium lone pair effect were rationalized in terms of the natural J-coupling analysis within the framework of the natural bond orbital approach., (Copyright © 2012 John Wiley & Sons, Ltd.)