Magnetic resonance imaging characterization of intact smoked cigarettes

Axelson, David E.; Wooten, Jan B.

doi:10.1016/j.jaap.2006.07.005

Cited by 7 publications

(5 citation statements)

References 24 publications

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“…During pyrolysis, K increases the formation of the low‐molecular‐weight species by fragmentation, ring opening, and dehydration reactions and inhibits the formation of anhydrosugars . During biomass pyrolysis, the formation of a liquid intermediate phase has been observed . This intermediate is very important for the chemical mechanisms that occur during pyrolysis because it is a precursor of gas/volatiles/char and it can control the composition of the products strongly.…”

Section: Introductionsupporting

confidence: 77%

“…[37,42] During biomass pyrolysis, the formation of al iquid intermediate phase has been observed. [43][44][45][46] This intermediate is very important for the chemical mechanisms that occur during pyrolysis because it is ap recursor of gas/volatiles/char and it can control the composition of the products strongly. The composition of the liquid intermediate phase produced during cellulose fast pyrolysis has been analyzed by LØdØ et al [47] and Piskorz et al [48] Our group has provided the first experimental evidencea nd quantification of this intermediate liquid phase by in situ 1 HNMR spectroscopy (or protonm agnetic resonancet hermala nalysis; PMRTA [49] )d uringb iomass pyrolysis.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques

et al. 2016

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Complementary analytical methods have been usedto study the effect of potassium on the primary pyrolysis mechanisms of cellulose and miscanthus. Thermogravimetry, calorimetry, high temperature 1 H NMR (in-situ and real time analysis of the fluid phase formed during pyrolysis) and water extraction of quenched char followed by SEC/MS-ELSD (size exclusion chromatography coupled with mass spectrometry and evaporative light scattering detector have been combined). Pyrolysis was conducted under fixed bed conditions to impose similar mass transfer conditions as TGA/DSC and 1 H NMR to produce charfor SEC/MS. Potassium impregnated in cellulose suppresses the formation of anhydro-sugars measuredby SEC/MS, reduces the formation of mobile protons as observed by in-situ 1 H NMR and gives rise to a mainly exothermic signal (by calorimetry). Interestingly, the evolution of mobile protons formed from Kimpregnated cellulose follows with a very similar pattern the evolution of the mass loss rate with the mobile protons are formed before mass loss commences during pure cellulose pyrolysis. This methodology has been also applied to miscanthus, demineralised miscanthus, potassium re-impregnated miscanthus after demineralization, raw oak and douglas fir. We discuss the mechanism of primary pyrolysis of biomass and notably highlight the importance of the intermediate liquid phase.

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques

et al. 2016

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“…20,24 Magnetic resonance imaging has been used at room temperature to study combustion in burning cigarettes after quench of cigarettes. 25 Imaging methods were employed to monitor substances with high molecular mobility, such as water, smoke condensate, and waxy materials, and more rigid components, such as tobacco cell wall polysaccharides and cellulose acetate fibers inside the filter. This advanced imaging method gave two-dimensional distribution of combustion and pyrolysis products deposited on the unburned portion of tobacco.…”

Section: Introductionmentioning

confidence: 99%

“…This advanced imaging method gave two-dimensional distribution of combustion and pyrolysis products deposited on the unburned portion of tobacco. 25 Real time imaging of biomass pyrolysis in the hot stage of a microscope also gave important new findings on the evolution of biomass tissue such as cell wall expansion, contraction, and evolution of macroporosity during pyrolysis. 20 To the best of our knowledge, this work is the only one dealing with in situ observations and liquid products formation in relation to cell wall evolution.…”

Section: Introductionmentioning

confidence: 99%

In Situ Analysis of Biomass Pyrolysis by High Temperature Rheology in Relations with¹H NMR

et al. 2012

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The extent of softening during biomass pyrolysis is of high importance for fundamentals and reactors design but was not yet quantified in situ. We provide the first in situ rheology and 1H NMR analysis during the pyrolysis of biomass (Miscanthus), microgranular cellulose, ethanol organosolv lignin, and xylan. In situ rheology reveals the viscoelastic behavior of the materials. The softening, resolidification (char formation), swelling, and shrinking behaviors are quantified during pyrolysis in real-time. These phenomena are discussed. The 1H NMR analysis gives the mobility of protons developed during pyrolysis. A viscous and mobile material is formed during cellulose and xylan pyrolysis, even at a slow heating rate (5 K min–1), by products at liquid phase under reaction temperatures. For lignin, a soft material and mobility are first formed by glass transition phase, then overlapped with covalent bond scission, leading to a completely mobile material. The comparison between 1H NMR and rheology results shows that mobile liquid-like products are trapped inside elastic solid-like cavities. Strong interactions between polymers in the native biomass network are evidenced. Cellulose tends to impose its visco-elastic behaviors to the polymers network during biomass pyrolysis. Rheological signatures are also of practical interest to design feeders and reactors for polymers biosourcing, biomass gasification, or combustion.

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“…One of the main conclusions of in situ X-ray analysis of cellulose pyrolysis is that the mobility of the xylan and lignin polymers might strongly influence the cellulose decomposition in its native form. [12] The formation of a liquid or mobile intermediate phase has been known for about a century for wood pyrolysis [2] and has been evidenced mainly by microscopic analysis [5c,e, 13] and by NMR imaging, [14] but not yet from in situ high-temperature NMR analysis. Although it is very important for chemical mechanisms, [10,12,15] mass transfer [13d-g] and consequently the selectivity of the thermochemical processes, [3d, 13g, 16] the mobility of these intermediate species and its origin have not been investigated.…”

Section: Introductionmentioning

confidence: 99%

The Origin of Molecular Mobility During Biomass Pyrolysis as Revealed by In situ ¹H NMR Spectroscopy

Dufour

Castro-Dı́az

Brosse³

et al. 2012

ChemSusChem

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The thermochemical conversion of lignocellulosic biomass feedstocks offers an important potential route for the production of biofuels and value-added green chemicals. Pyrolysis is the first phenomenon involved in all biomass thermochemical processes and it controls to a major extent the product composition. The composition of pyrolysis products can be affected markedly by the extent of softening that occurs. In spite of extensive work on biomass pyrolysis, the development of fluidity during the pyrolysis of biomass has not been quantified. This paper provides the first experimental investigation of proton mobility during biomass pyrolysis by in situ (1)H NMR spectroscopy. The origin of mobility is discussed for cellulose, lignin and xylan. The effect of minerals on cellulose mobility is also investigated. Interactions between polymers in the native biomass network are revealed by in situ (1)H NMR analysis.

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Magnetic resonance imaging characterization of intact smoked cigarettes

Cited by 7 publications

References 24 publications

Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques

Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques

In Situ Analysis of Biomass Pyrolysis by High Temperature Rheology in Relations with¹H NMR

The Origin of Molecular Mobility During Biomass Pyrolysis as Revealed by In situ ¹H NMR Spectroscopy

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Magnetic resonance imaging characterization of intact smoked cigarettes

Cited by 7 publications

References 24 publications

Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques

Effect of Potassium on the Mechanisms of Biomass Pyrolysis Studied using Complementary Analytical Techniques

In Situ Analysis of Biomass Pyrolysis by High Temperature Rheology in Relations with1H NMR

The Origin of Molecular Mobility During Biomass Pyrolysis as Revealed by In situ 1H NMR Spectroscopy

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In Situ Analysis of Biomass Pyrolysis by High Temperature Rheology in Relations with¹H NMR

The Origin of Molecular Mobility During Biomass Pyrolysis as Revealed by In situ ¹H NMR Spectroscopy