TY - JOUR
T1 - Release of P from Pyrolysis, Combustion, and Gasification of Biomass - A Model Compound Study
AU - Lidman Olsson, Emil O.
AU - Glarborg, Peter
AU - Leion, Henrik
AU - Dam-Johansen, Kim
AU - Wu, Hao
PY - 2021
Y1 - 2021
N2 - Phosphorus-rich biomass can cause operational problems in combustion
units. Na-phytate, a model compound used to simulate phosphorus in
biomass, was studied in a laboratory-scale reactor under temperature and
gas atmosphere conditions relevant for pyrolysis, combustion, and
gasification in fixed bed or fluidized bed reactors to understand the P
and Na release behavior. Solid residues from Na-phytate thermal
conversion were analyzed using ICP with optical emission spectrometry in
order to quantify the P and Na release. The release mechanism was
evaluated based on FTIR spectroscopy analysis of the residues,
measurement of the flue gas CO/CO2 concentration,
characterization of flue gas particles using SEM with EDS, and
thermodynamic equilibrium calculations. Na-phytate decomposed in several
steps under a nitrogen atmosphere, starting with condensation of the
phosphate OH groups, followed by carbonization in the temperature range
300–420 °C. In the carbonization process, the phosphate units detached
from the carbon structure and formed cyclic NaPO3. Above 800 °C, the C in the char reacted with the melted NaPO3
to form CO and gaseous elemental P. When the char produced from flash
pyrolysis of Na-phytate at 800 °C for 10 min was exposed to 1% O2, 10% CO2, or 10% H2O (in N2),
the release of Na and P to the gas phase in the temperature range
800–1000 °C was around 0–7%. However, the release of P in an inert
atmosphere, with a holding time of 2 h or until full char conversion had
been achieved, increased from around 4% at 800 °C to almost 30% at 1000
°C. The results indicated that carbothermic reduction reaction is
responsible for the release of P and that NaPO3 vaporization
is not the dominating mechanism for P and Na release at temperatures
below 1000 °C. A small amount of P was released in the O2, CO2, and H2O containing gases because these gas species consumed the char and thereby inhibited the release of P.
AB - Phosphorus-rich biomass can cause operational problems in combustion
units. Na-phytate, a model compound used to simulate phosphorus in
biomass, was studied in a laboratory-scale reactor under temperature and
gas atmosphere conditions relevant for pyrolysis, combustion, and
gasification in fixed bed or fluidized bed reactors to understand the P
and Na release behavior. Solid residues from Na-phytate thermal
conversion were analyzed using ICP with optical emission spectrometry in
order to quantify the P and Na release. The release mechanism was
evaluated based on FTIR spectroscopy analysis of the residues,
measurement of the flue gas CO/CO2 concentration,
characterization of flue gas particles using SEM with EDS, and
thermodynamic equilibrium calculations. Na-phytate decomposed in several
steps under a nitrogen atmosphere, starting with condensation of the
phosphate OH groups, followed by carbonization in the temperature range
300–420 °C. In the carbonization process, the phosphate units detached
from the carbon structure and formed cyclic NaPO3. Above 800 °C, the C in the char reacted with the melted NaPO3
to form CO and gaseous elemental P. When the char produced from flash
pyrolysis of Na-phytate at 800 °C for 10 min was exposed to 1% O2, 10% CO2, or 10% H2O (in N2),
the release of Na and P to the gas phase in the temperature range
800–1000 °C was around 0–7%. However, the release of P in an inert
atmosphere, with a holding time of 2 h or until full char conversion had
been achieved, increased from around 4% at 800 °C to almost 30% at 1000
°C. The results indicated that carbothermic reduction reaction is
responsible for the release of P and that NaPO3 vaporization
is not the dominating mechanism for P and Na release at temperatures
below 1000 °C. A small amount of P was released in the O2, CO2, and H2O containing gases because these gas species consumed the char and thereby inhibited the release of P.
U2 - 10.1021/acs.energyfuels.1c02397
DO - 10.1021/acs.energyfuels.1c02397
M3 - Journal article
SN - 0887-0624
VL - 35
SP - 15817
EP - 15830
JO - Energy and Fuels
JF - Energy and Fuels
IS - 19
ER -