4 research outputs found
Handheld probe illustration.
No full text<p>(a) Probe compared to a quarter coin (H: height 37.24 mm, W: width 32.43 mm, L: length 136.7 mm). (b) Optics layout inside the probe. (c) Image of the probe held by hand.</p
Potential of Using Coal Tar as a Quenching Agent for Coal Gasification
No full textTo
reduce water usage and wastewater treatment in coal gasification
processing, the use of non-aqueous quenching agents was proposed.
The purpose of this study is to assess the potential of using coal
tar as a quenching agent for the Luger coal gasification. A low-temperature
gasification-derived coal tar and an ethylene tar obtained from the
petroleum naphtha cracking process in ethylene production were subjected
to thermal aging tests to determine the effect of thermal severity
on their viscosity and chemical composition. The viscosities of coal
tar and ethylene tar as a function of the aging time were similar
and relatively constant at 200 °C. At 250 °C, the coal tar
was more unstable and had a shorter viscosity increase onset time
than the ethylene tar. The tar samples before and after thermal aging
tests were subjected to gas chromatography–mass spectrometry
(GC–MS) and Fourier transform ion cyclotron resonance mass
spectrometry (FT-ICR MS) to determine the molecular composition. The
results indicated that olefins, especially aromatic olefins in the
coal tar, were unstable, which likely caused polymerization of coal
tar species during thermal aging and resulted in a short viscosity
increase onset time. By adding a polymerization inhibitor, the viscosity
increase onset time of coal tar was prolonged. The coal tar is potential
for use as a quenching agent for coal gasification
Characterization of Middle-Temperature Gasification Coal Tar. Part 2: Neutral Fraction by Extrography Followed by Gas Chromatography–Mass Spectrometry and Electrospray Ionization Coupled with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
No full textA commercial lignite gasification-derived middle-temperature
coal tar (MTCT) was subjected to acid–base extraction to obtain
acidic, basic, and neutral fractions. The neutral fraction was characterized
by mass spectrometry (MS) for hydrocarbon-group-type analysis and
further fractionated by extrography into six subfractions, which were
characterized by gas chromatography–mass spectrometry (GC–MS).
Saturate, aromatic, and resin fractions of the neutral fraction accounted
for 16.4, 47.6, and 36.0 wt %, respectively. The GC–MS analysis
showed that the first neutral subfraction (15.7 wt %) contained alkanes,
alkenes, and cycloalkanes; the second subfraction (52.0 wt %) contained
1–6-ring aromatics; the third subfraction (4.6 wt %) contained
neutral nitrogen compounds, such as indoles, carbazoles, and benzocarbazoles;
the fourth subfraction (8.2 wt %) contained neutral polar compounds,
such as C<sub>8</sub>–C<sub>28</sub> alkyl nitriles and aliphatic
and aromatic ketones, such as 4-, 5-, and 6-ketones and phenyl ketones,
derived from a series of propiophenone to decanophenone; the fifth
subfraction (14.9 wt %) contained 2-ketones and aromatic ketones,
such as acetophenones, indanones, and acetonaphthones; and most of
the sixth subfraction (1.3 wt %) cannot be eluted from GC. Electrospray
ionization (ESI) coupled with Fourier transform ion cyclotron resonance
mass spectrometry (FT-ICR MS) was used to analyze the third neutral
subfraction, which was enriched with neutral nitrogen compounds. In
addition to indoles, carbazoles, and benzocarbazoles, FT-ICR MS analysis
showed that dibenzocarbazoles and tribenzocarbazoles with various
carbon numbers were present in the third neutral subfraction
Characterization of Middle-Temperature Gasification Coal Tar. Part 3: Molecular Composition of Acidic Compounds
No full textCoal tar has been considered as a potential energy alternative
because of dwindling supplies of petroleum. To determine if the coal
tar could be refined and upgraded to produce clean transportation
fuels, detailed investigation of its composition is necessary, particularly
for identifying the acidic components that account for about one-quarter
of the weight of the coal tar. A middle-temperature coal tar (MTCT)
and its fractions were characterized by gas chromatography–mass
spectrometry (GC–MS) and negative-ion electrospray ionization
(ESI) Fourier transform ion cyclotron resonance mass spectrometry
(FT-ICR MS) with different ion transmission modes for high- and low-mass
ions. Analytical results of narrow distillation fractions from FT-ICR
MS agreed reasonably well with those from GC–MS, although each
technique has its own advantages and disadvantages. In this work,
FT-ICR MS was demonstrated to be capable of characterizing small molecules
of <100 Da using appropriate operation conditions, thus yielding
mass distributions to compare to GC–MS results. A continuous
distribution in double bond equivalent (DBE) and carbon number was
observed with the distillates of increasing boiling point, while the
composition of the distillation residue was much more complex than
that of distillates. Acidic compounds containing 1–7 oxygen
atoms were observed in the MTCT by FT-ICR MS, with O<sub>1</sub> and
O<sub>2</sub> classes being dominant. Various phenolic compounds with
1–4 aromatic rings were identified on the basis of literature
references, including some molecules having structures resembling
known biomarkers in petroleum and coal
