(534f) Studies of Hydrogen Loss Measurements in Biomass Pyrolysis Using Neutron Scattering and Optical Techniques
AIChE Annual Meeting
2024
2024 AIChE Annual Meeting
Forest and Plant Bioproducts Division
Synthesis and characterization of biomass-derived nanomaterials
Wednesday, October 30, 2024 - 2:00pm to 2:18pm
Pyrolysis of biomass is an interesting method to produce biofuel and char. During the pyrolysis at
temperatures above ca 200 °C there is a continuous loss of hydrogen (H) which can be measured in
situ by neutron radiography. Neutron radiography is a powerful tool to monitor hydrogen atoms inside
the bulk of the biomass. This is possible because neutrons show very strong attenuation to hydrogen,
compared to heavier elements such as carbon and oxygen. Gravimetry and differential
thermogravimetry show similar trends to H-release, however at temperatures above the main release
region differences appear. H-loss continues as temperature is raised, whereas mass loss mainly
determine by C and O loss is considerably weak. In order to get a better understanding of the
chemistry, one can use inelastic neutron scattering and vibrational spectroscopy (INS-NVS) to monitor
how the spectrum changes during pyrolysis. Up to ca 350 °C the composition can be fairly well
described as a superposition of the pseudo-components, hemicellulose (HC), cellulose (CE) and lignin
(LI). From the composition of the spectrum, these components appear to break down in order the
mentioned order, i.e., HC, CE and LI. LI appears to be the last component to fully break down. One
observes that the signal decreases as temperature is raised and that the spectrum in the lower energy
region acquires similarities to that of imperfect graphene-like structures reported by other
researchers’ studies on hydrogenated graphene. In conclusion, we can say that neutron scattering,
which is sensitive to hydrogen, is a powerful technique to monitor and measure changes in the amount
of H and how H is chemically bound. Another important point is that neutrons allow us to measure H
inside the bulk of pyrolyzing and carbonizing biomass, which is kept inside metal containers during the
experiments. Neutron scattering results are also be compared with Raman scattering and Fourier
transform infrared radiation spectroscopy results.
These studies and results that are presented are based on collaborative work between different
researchers from the Oak Ridge National Laboratory, the European Spallation Source and Lund
University, Sweden, where the presenter is employed. The presenter wants to specially acknowledge
and thank the collaborators for their support.
temperatures above ca 200 °C there is a continuous loss of hydrogen (H) which can be measured in
situ by neutron radiography. Neutron radiography is a powerful tool to monitor hydrogen atoms inside
the bulk of the biomass. This is possible because neutrons show very strong attenuation to hydrogen,
compared to heavier elements such as carbon and oxygen. Gravimetry and differential
thermogravimetry show similar trends to H-release, however at temperatures above the main release
region differences appear. H-loss continues as temperature is raised, whereas mass loss mainly
determine by C and O loss is considerably weak. In order to get a better understanding of the
chemistry, one can use inelastic neutron scattering and vibrational spectroscopy (INS-NVS) to monitor
how the spectrum changes during pyrolysis. Up to ca 350 °C the composition can be fairly well
described as a superposition of the pseudo-components, hemicellulose (HC), cellulose (CE) and lignin
(LI). From the composition of the spectrum, these components appear to break down in order the
mentioned order, i.e., HC, CE and LI. LI appears to be the last component to fully break down. One
observes that the signal decreases as temperature is raised and that the spectrum in the lower energy
region acquires similarities to that of imperfect graphene-like structures reported by other
researchers’ studies on hydrogenated graphene. In conclusion, we can say that neutron scattering,
which is sensitive to hydrogen, is a powerful technique to monitor and measure changes in the amount
of H and how H is chemically bound. Another important point is that neutrons allow us to measure H
inside the bulk of pyrolyzing and carbonizing biomass, which is kept inside metal containers during the
experiments. Neutron scattering results are also be compared with Raman scattering and Fourier
transform infrared radiation spectroscopy results.
These studies and results that are presented are based on collaborative work between different
researchers from the Oak Ridge National Laboratory, the European Spallation Source and Lund
University, Sweden, where the presenter is employed. The presenter wants to specially acknowledge
and thank the collaborators for their support.