Authors:I. Pitkänen, J. Huttunen, H. Halttunen, and R. Vesterinen
FTIR spectrometry combined with TG provides information regarding mass changes in a sample and permits qualitative identification
of the gases evolved during thermal degradation. Various fuels were studied: coal, peat, wood chips, bark, reed canary grass
and municipal solid waste. The gases evolved in a TG analyser were transferred to the FTIR via a heated teflon line. The spectra
and thermoanalytical curves indicated that the major gases evolved were carbon dioxide and water, while there were many minor
gases, e.g. carbon monoxide, methane, ethane, methanol, ethanol, formic acid, acetic acid and formaldehyde. Separate evolved
gas spectra also revealed the release of ammonia from biomasses and peat. Sulphur dioxide and nitric oxide were found in some
cases. The evolution of the minor gases and water parallelled the first step in the TG curve. Solid fuels dried at 100C mainly
lost water and a little ammonia.
Although thermogravimetric analysis (TG) has become an indispensable tool for the analysis and characterization of materials,
its scope is limited as no information is obtained about the qualitative aspects of the evolved gases during the thermal decomposition.
For processes involving mass loss, a powerful technique to provide this missing information is Fourier transform infrared
spectroscopy (FT-IR) in combination with TG. It supplies a comprehensive understanding of thermal events in a reliable and
meaningful way as data are obtained from a single sample under the same conditions.
The coupling TG/FT-IR is used in fuel analysis for the identification of residual volatiles, to determine their sequence of
release and to resolve thermogravimetric curves. In this work, the usefulness of TG/FT-IR for characterizing middle distillate
fuel residues is illustrated with some typical examples of recent application. A Bio-Rad FTS 25 FT-IR spectrometer coupled
with a TA Instruments TGA 2950 thermogravimetric analyzer was used for data aquisition.
The results obtained demonstrate the utility of this combined technique in determining the decomposition pathway of tarry
materials at various stages of pyrolysis, thereby allowing new insights into the complex thermal behaviour of hydrocarbon
unconventional fuels in generator processes. Much of the waste is a mixture of composite, not suitable for processing recycled material. However, if they have an energetic potential (due to containing chemical energy), then thermal processes stand in the
Authors:G. Timofeev, V. Gabeskiria, G. Simakin, V. Mishenev, A. Bevz, and A. Rykov
As a rule the analysis of nuclear oxide fuel includes the determination of uranium, plutonium, their isotopic composition,
cation impurities, carbon, nitrogen, chlorine, fluorine, oxygen coefficient. In this paper we discuss different methods for
the a analysis of unirradiated uranium and plutonium oxide fuelds used in the laboratories of the Analytical Chemistry Department:
coulometry, emission analysis, chromatography, X-ray analysis. Much consideration is being given to the analysis of uranium
and plutonium oxide samples and uranium-plutonium mixed fuels irradiated in the BOR-60 using mass-spectrometric (isotope dilution
method) and radiometric techniques. The results of uranium and plutonium determination by these methods are compared. The
main analytical characteristics of the methods are given.
Authors:S. Casu, S. Galvagno, A. Calabrese, G. Casciaro, M. Martino, A. Russo, and Sabrina Portofino
Summary Refuse derived fuels (RDF) characterization and pyrolysis behaviour, carried out by means of thermogravimetric analysis, infrared and mass spectroscopy, are presented. Thermal degradation of RDF takes place through three main mass loss stages; the analyses of evolved gas allow us to discriminate the contributions of the different fractions (paper, LDPE, wood, rubber, etc.) to the global decomposition. Furthermore thermogravimetry (TG) was used for the determination of kinetic parameters, using the differential method. In order to set up the conditions of production of a good quality pyrolysis gas, the operating conditions of RDF in a pyrolysis reactor have been simulated. Data show that the volatile fraction grows with the temperature, together with the relative conversion, and that light volatile fraction (hydrogen, ethyne, etc.) gets richer, at the expense of superior homologous hydrocarbons.
Fire safety on fuel containers
can be improved at its initial stage if flame spreading can be controlled.
Therefore, the understanding of the fundamental processes that control flame
spreading will help us to determine a few control parameters that could be
useful to improve security in fuel deposits. A series of experiments have
been conducted in different fuel containers that helped to understand the
basic mechanisms involved. A new phenomenon of convection ahead of the flame
is observed in liquid fuels that do not appear in solid fuels. Finally, two
control factors have been found useful to control fire spread: the initial
fuel surface temperature and the convection zone observed in front of the
flame. The first experimental results observed controlling these two factors
led flame to spreading velocities of order 1 cm s–1
and, in some cases, flame extinguishes.
Authors:Q. Kwok, D. Jones, G. Nunez, J. Charland, and S. Dionne
Three bio-fuels with or without additives and their fly ash samples were characterized using simultaneous Thermogravimetry-Differential
Thermal Analysis-Fourier Transform Infrared Spectrometry-Mass Spectrometry (TG-DTA-FTIR-MS), X-ray Diffraction (XRD), X-ray
Fluorescence (XRF), and Scanning Electron Microscopy-Energy Dispersive Spectrometry (SEM-EDS). The results show that the additives
increase the reactivity of the bio-fuel during combustion. The additives also significantly decrease the amount of unburned
carbon in the fly ash. The additives affect the compounds formed in the fly ash sample, and consequently the thermal behaviour
of the fly ash. The fly ash samples are thermally stable in air up to 100C. The fly ash samples contain fine particles with
irregular shape, small round particles, and large hollow spherical particles with entrapped gases.