Pine
cone (PC) is a potential biomass energy source and is rich
in nonstructural substances (NSS). To understand the impact of these
NSS on the pyrolysis behavior and its products, in this study, phenol
alcohol extraction was used for the separation of NSS from PC (the
PC after separation of NSS was labeled as A-PC), and then thermogravimetric
analysis −Fourier transform infrared and PY-gas chromatography/MS
detection techniques were used to conduct a systematic comparison
of the thermal degradation behaviors and kinetics parameters of PC
and A-PC. Results showed that the N content of PC was higher than
that of other biomass, and the activation energies of PC and A-PC
generally decreased at first and then increased as the conversion
rate increased. Furthermore, the activation energy of PC decreased
with conversion rates in the range of 0.25–0.30, while A-PC
lagged significantly behind PC. On the other hand, the maximum absorption
peak of CH4 for PC was higher than that of A-PC, and the
maximum absorption peak of CO2 was quite the opposite.
After extracting NSS from the PC, its activation energy was significantly
increased.
Using apricot shell lignin as a raw material,
the effects of torrefaction
temperatures (160, 200, 240, and 280 °C) on the properties of
torrefied products were studied, and the catalytic pyrolysis experiments
of the torrefied lignin under the HZSM-5 catalyst were carried out.
The results showed that the oxygen content in lignin was greatly reduced
and the higher heating values (HHV) gradually increased, the absorption
peak of oxygen-containing functional groups gradually became weaker,
and the content of the β-O-4 bond gradually decreased. At 280
°C, the C/O ratio reaches the maximum value of 2.17, and the
calorific value increases to 24.22 MJ/kg. The removed oxygen element
is converted into oxygen-containing components in the gas (mainly
CO2 and H2O) and liquid products (mainly guaiacol
phenol). After catalytic pyrolysis of torrefied lignin, it was found
that with the increase of torrefaction temperature, the relative content
of aromatics increased first and then decreased slightly; the aromatics
reached the maximum value of 60.63% at 240 °C; acids decreased
significantly; ketones, aldehydes, and furans changed little; and
torrefaction played a positive role in the conversion of lignin to
aromatics.
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