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Thermogravimetric monitoring of oil refinery sludge
26 September 2013,
06:14:49
Publication date: Available online 23
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Agustín G. Barneto , Julia Moltó , José Ariza , Juan A. Conesa
The present work has two dimensions: analytical and environmental. On the one hand we proved that thermogravimetric analysis can be used to perform fast characterization of oil refinery sludge. To this end, thermogravimetric curves were deconvoluted by using autocatalytic kinetics to take into account acceleratory phases in a thermal degradation performed in oxygen-containing atmosphere or at high heating rates. Based on thermogravimetric results, oil refinery sludge was modeled in terms of various fractions (pseudo-components) which degrade as major oil cuts. On the other hand, as an alternative to landfill, we have seen that Soxhlet extraction allows recovery almost half of the weight of sludge as a mixture of hydrocarbons, similar to gas-oil, which burns without residue. This ensures both, waste inerting and significant reduction in sludge volume.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Agustín G. Barneto , Julia Moltó , José Ariza , Juan A. Conesa
The present work has two dimensions: analytical and environmental. On the one hand we proved that thermogravimetric analysis can be used to perform fast characterization of oil refinery sludge. To this end, thermogravimetric curves were deconvoluted by using autocatalytic kinetics to take into account acceleratory phases in a thermal degradation performed in oxygen-containing atmosphere or at high heating rates. Based on thermogravimetric results, oil refinery sludge was modeled in terms of various fractions (pseudo-components) which degrade as major oil cuts. On the other hand, as an alternative to landfill, we have seen that Soxhlet extraction allows recovery almost half of the weight of sludge as a mixture of hydrocarbons, similar to gas-oil, which burns without residue. This ensures both, waste inerting and significant reduction in sludge volume.
Flame retardancy and thermal degradation behaviors of polypropylene composites with novel intumescent flame retardant and manganese dioxide
26 September 2013,
06:14:49
Publication date: Available online 23
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Caimin Feng , Yi Zhang , Dong Liang , Siwei Liu , Zhenguo Chi , Jiarui Xu
The flame retardancy and thermal degradation behavior of polypropylene composites containing ammonium polyphosphate (APP), novel charring agent (CNCA-DA) and manganese dioxide (MnO2) were characterized by limiting oxygen index (LOI), UL-94 measurement, cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). It was found that a small amount of MnO2 could dramatically increase the LOI value, UL rating of the PP/IFR systems, and reduce the combustion parameters of PP/IFR system from CCT test, including peak heat release rate (p-HRR), total heat release (THR), and smoke production rate (SPR). The catalytic effectivity (CAT-EFF) results showed that when 1wt. % MnO2 was added, it had the highest CAT-EFF, and could promote the LOI value of the composites from 27.1 to 30.7. The TGA data revealed that MnO2 could change the degradation behavior of the IFR and PP/IFR, improve the thermal stability of the PP/IFR systems at high temperature and increase the char residue. The morphological structures observed by digital photos and SEM indicated that MnO2 could effectively help to form more continuous and compact intumescent char layer on the outer surface to protect the underlying materials from burning. The EDS results illustrated that the existence of MnO2 could promote to remain more P and O in the char layer.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Caimin Feng , Yi Zhang , Dong Liang , Siwei Liu , Zhenguo Chi , Jiarui Xu
The flame retardancy and thermal degradation behavior of polypropylene composites containing ammonium polyphosphate (APP), novel charring agent (CNCA-DA) and manganese dioxide (MnO2) were characterized by limiting oxygen index (LOI), UL-94 measurement, cone calorimeter test (CCT), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). It was found that a small amount of MnO2 could dramatically increase the LOI value, UL rating of the PP/IFR systems, and reduce the combustion parameters of PP/IFR system from CCT test, including peak heat release rate (p-HRR), total heat release (THR), and smoke production rate (SPR). The catalytic effectivity (CAT-EFF) results showed that when 1wt. % MnO2 was added, it had the highest CAT-EFF, and could promote the LOI value of the composites from 27.1 to 30.7. The TGA data revealed that MnO2 could change the degradation behavior of the IFR and PP/IFR, improve the thermal stability of the PP/IFR systems at high temperature and increase the char residue. The morphological structures observed by digital photos and SEM indicated that MnO2 could effectively help to form more continuous and compact intumescent char layer on the outer surface to protect the underlying materials from burning. The EDS results illustrated that the existence of MnO2 could promote to remain more P and O in the char layer.
Mössbauer studies on thermal decomposition of rubidium bis(citrato)ferrate(III) precursor prepared by precursor method
26 September 2013,
06:14:49
Publication date: Available online 23
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Manik Gupta , Munish Gupta , Vivek Sheel Jaswal , B.S Randhawa
Thermal decomposition studies of rubidium bis(citrato)ferrate(III) trihydrate precursor has been carried out in flowing air atmosphere from ambient temperature to 900°C. The precursor material was prepared by using solution based precursor method and different physico-chemical techniques i.e. simultaneous Thermogravimetry- Differential Thermogravimetry - Differential Thermal Analysis (TG-DTG-DTA), X-Ray Diffraction (powder), Transmission Electron Microscopy (TEM), Infra-red (IR) and Mössbauer spectroscopy have been employed to characterize the intermediates and end product. After dehydration, anhydrous precursor undergoes exothermic decomposition to yield various intermediates like metal carbonate, metal oxide and α-Fe2O3, followed by a solid-state reaction to form final ferrite product above 800°C. XRD study reveals the formation of pure and nanosized rubidium ferrites with α-LiFeO2 type geometry. TEM micrograph confirms the nanosized particles with average size of 65nm. For the sake of comparison, similar ferrite has also been prepared by the combustion method at a comparatively lower temperature (600 0C) and in less time.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Manik Gupta , Munish Gupta , Vivek Sheel Jaswal , B.S Randhawa
Thermal decomposition studies of rubidium bis(citrato)ferrate(III) trihydrate precursor has been carried out in flowing air atmosphere from ambient temperature to 900°C. The precursor material was prepared by using solution based precursor method and different physico-chemical techniques i.e. simultaneous Thermogravimetry- Differential Thermogravimetry - Differential Thermal Analysis (TG-DTG-DTA), X-Ray Diffraction (powder), Transmission Electron Microscopy (TEM), Infra-red (IR) and Mössbauer spectroscopy have been employed to characterize the intermediates and end product. After dehydration, anhydrous precursor undergoes exothermic decomposition to yield various intermediates like metal carbonate, metal oxide and α-Fe2O3, followed by a solid-state reaction to form final ferrite product above 800°C. XRD study reveals the formation of pure and nanosized rubidium ferrites with α-LiFeO2 type geometry. TEM micrograph confirms the nanosized particles with average size of 65nm. For the sake of comparison, similar ferrite has also been prepared by the combustion method at a comparatively lower temperature (600 0C) and in less time.
Pyrolysis of propane for CVI of pyrocarbon Part IV: Main Pathways involved in and pyrocarbon deposit
26 September 2013,
06:14:49
Publication date: Available online 23
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): I. Ziegler-Devin , R. Fournet , R. Lacroix , P.M. Marquaire
A detailed kinetic mechanism modeling both gas and surface reactions involved in Chemical Vapor Deposition (CVD) of pyrocarbon has been developed. Simulated results have been validated by comparison with experimental data. Pyrolytic carbon deposit was realized on carbon fibers by the pyrolysis of propane at low pressure (< 3kPa) and high temperature (≈ 1200K). The kinetic mechanism consists in 608 gaseous and 275 surface elementary steps, and is efficient to predict both pyrocarbon deposit rate and gas phase composition vs. temperatures, residence time ranging and fibers surface to reactant volume ratio. In this paper, the main pyrocarbon deposition pathways are proposed by using flow rate and sensitivity analyses. In our experimental conditions, pyrocarbon seems to be mainly formed by the deposition of small unsaturated species (such as acetylene and ethylene) and methyl radicals. Pyrocarbon deposition rate is controlled by the gas phase composition (H2, CH3, C2H2 and C2H4) and a few surface key reactions.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): I. Ziegler-Devin , R. Fournet , R. Lacroix , P.M. Marquaire
A detailed kinetic mechanism modeling both gas and surface reactions involved in Chemical Vapor Deposition (CVD) of pyrocarbon has been developed. Simulated results have been validated by comparison with experimental data. Pyrolytic carbon deposit was realized on carbon fibers by the pyrolysis of propane at low pressure (< 3kPa) and high temperature (≈ 1200K). The kinetic mechanism consists in 608 gaseous and 275 surface elementary steps, and is efficient to predict both pyrocarbon deposit rate and gas phase composition vs. temperatures, residence time ranging and fibers surface to reactant volume ratio. In this paper, the main pyrocarbon deposition pathways are proposed by using flow rate and sensitivity analyses. In our experimental conditions, pyrocarbon seems to be mainly formed by the deposition of small unsaturated species (such as acetylene and ethylene) and methyl radicals. Pyrocarbon deposition rate is controlled by the gas phase composition (H2, CH3, C2H2 and C2H4) and a few surface key reactions.
Hydrothermal wood processing using borax decahydrate and sodium borohydride
26 September 2013,
06:14:49
Publication date: Available online 21
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Kubilay Tekin , Mehmet K. Akalın , Sema Bektaş , Selhan Karagöz
Hydrothermal liquefaction experiments were carried out at 250, 300 and 350°C with the use of an additive (either borax decahydrate (Na2B4O7.10H2O) or sodium borohydride (NaBH4).) The effects of both temperature and types of additives on the product distributions and bio-crude compositions were viewed. The use of additives (either Na2B4O7.10H2O or NaBH4) increased bio-crude yields at all liquefaction temperatures. The highest bio-crude yield was achieved with Na2B4O7.10H2O at 300°C. The use of additives (either Na2B4O7.10H2O or NaBH4) decreased the char yield at 300 and 350°C. The heating values of ether extracts from all experimental runs including the runs without additives were close to each other. However, the heating values of the acetone extracts from chemical runs were higher than the heating values of the non-chemical run. The highest heating value of the acetone extract was 28.05MJ.kg−1 and it was obtained from the run with Na2B4O7.10H2O at 300°C. The identified compounds in ether extracts and acetone extracts were mainly oxygenated compounds. The compositions of ether extracts and acetone extracts were affected when using additives.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Kubilay Tekin , Mehmet K. Akalın , Sema Bektaş , Selhan Karagöz
Hydrothermal liquefaction experiments were carried out at 250, 300 and 350°C with the use of an additive (either borax decahydrate (Na2B4O7.10H2O) or sodium borohydride (NaBH4).) The effects of both temperature and types of additives on the product distributions and bio-crude compositions were viewed. The use of additives (either Na2B4O7.10H2O or NaBH4) increased bio-crude yields at all liquefaction temperatures. The highest bio-crude yield was achieved with Na2B4O7.10H2O at 300°C. The use of additives (either Na2B4O7.10H2O or NaBH4) decreased the char yield at 300 and 350°C. The heating values of ether extracts from all experimental runs including the runs without additives were close to each other. However, the heating values of the acetone extracts from chemical runs were higher than the heating values of the non-chemical run. The highest heating value of the acetone extract was 28.05MJ.kg−1 and it was obtained from the run with Na2B4O7.10H2O at 300°C. The identified compounds in ether extracts and acetone extracts were mainly oxygenated compounds. The compositions of ether extracts and acetone extracts were affected when using additives.
Graphical abstract
Thermal Deoxygenation and Pyrolysis of Oleic Acid
26 September 2013,
06:14:49
Publication date: Available online 20
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Justice Asomaning , Paolo Mussone , David C. Bressler
The primary objective of this work was to study the pyrolytic conversion of mono unsaturated fatty acids to hydrocarbon products for use as renewable chemicals and fuels. Oleic acid (cis-9-octadecenoic acid) was selected as a model mono unsaturated compound. Batch pyrolysis reactions were conducted over a combination of temperatures from 350 to 450°C and times ranging from 0.5 to 8h. Gas chromatography and mass spectroscopy were used to analyze and identify products in the gas and liquid product fractions. Analysis of the gas phase showed concurrent production of CO and CO2, indicating that deoxygenation reaction proceeded through both decarbonylation and decarboxylation mechanisms. The gas product contained also alkanes and alkenes with carbon numbers ranging from C1 to C5. Analysis of the liquid fraction revealed series of n-alkanes, alkenes and fatty acids, including stearic acid. The presence of the unsaturation resulted in cracking at the allylic C-C and predominance of C6 to C10 hydrocarbons and C9 and C10 fatty acids. This work uncovers the dominant reaction pathways in the pyrolysis of mono unsaturated free fatty acids and demonstrates the viability of this non-catalyzed conversion technology to produce renewable hydrocarbons compatible with the existing petrochemical infrastructure.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Justice Asomaning , Paolo Mussone , David C. Bressler
The primary objective of this work was to study the pyrolytic conversion of mono unsaturated fatty acids to hydrocarbon products for use as renewable chemicals and fuels. Oleic acid (cis-9-octadecenoic acid) was selected as a model mono unsaturated compound. Batch pyrolysis reactions were conducted over a combination of temperatures from 350 to 450°C and times ranging from 0.5 to 8h. Gas chromatography and mass spectroscopy were used to analyze and identify products in the gas and liquid product fractions. Analysis of the gas phase showed concurrent production of CO and CO2, indicating that deoxygenation reaction proceeded through both decarbonylation and decarboxylation mechanisms. The gas product contained also alkanes and alkenes with carbon numbers ranging from C1 to C5. Analysis of the liquid fraction revealed series of n-alkanes, alkenes and fatty acids, including stearic acid. The presence of the unsaturation resulted in cracking at the allylic C-C and predominance of C6 to C10 hydrocarbons and C9 and C10 fatty acids. This work uncovers the dominant reaction pathways in the pyrolysis of mono unsaturated free fatty acids and demonstrates the viability of this non-catalyzed conversion technology to produce renewable hydrocarbons compatible with the existing petrochemical infrastructure.
Pyrolysis Temperature-Dependent Release of Dissolved Organic Carbon from Plant, Manure, and Biorefinery Wastes
26 September 2013,
06:14:49
Publication date: Available online 19
September 2013
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Minori Uchimiya , Tsutomu Ohno , Zhongqi He
Limited information is available to understand the chemical structure of biochar's labile dissolved organic carbon (DOC) fraction that will alter soil organic carbon (SOC) composition. This study utilized the high sensitivity of fluorescence excitation-emission (EEM) spectrophotometry to understand the structural changes in biochar-derived DOC as a function of (1) chemical property of feedstock and (2) pyrolysis temperature (350-800°C). Regardless of feedstock (almond shell, broiler litter, lignin, cottonseed hull, and pecan shell), low temperature (350-400°C) pyrolysis shifted EEM of hot water (80°C for 16h) extracts towards longer emission wavelengths, higher aromaticity regions. Five component parallel factor (PARAFAC) modeling of EEM afforded: (C1) (poly)phenolic pyrolysis products and other water-soluble aromatic structures similar to fulvic-like SOC; (C2-C3) aromatic structures similar to humic-like SOC having low water solubility that decomposed above 350°C; (C4) carboxyl and other transient thermochemical conversion intermediates that decomposed above 500°C; and (C5) thermally stable DOC fraction of lignin-rich biomass (pecan shell and lignin). Relative contribution of fulvic-like component exceeded that of humic-like components, and increased as a function of pyrolysis temperature. The C4 showed disproportionately high contributions to 500°C broiler litter and cottonseed hull biochars. The carboxyl-enriched DOC of biochars pyrolyzed at 350-500°C can have diverse environmental consequences, including the mobilization of heavy metals.
Source:Journal of Analytical and Applied Pyrolysis
Author(s): Minori Uchimiya , Tsutomu Ohno , Zhongqi He
Limited information is available to understand the chemical structure of biochar's labile dissolved organic carbon (DOC) fraction that will alter soil organic carbon (SOC) composition. This study utilized the high sensitivity of fluorescence excitation-emission (EEM) spectrophotometry to understand the structural changes in biochar-derived DOC as a function of (1) chemical property of feedstock and (2) pyrolysis temperature (350-800°C). Regardless of feedstock (almond shell, broiler litter, lignin, cottonseed hull, and pecan shell), low temperature (350-400°C) pyrolysis shifted EEM of hot water (80°C for 16h) extracts towards longer emission wavelengths, higher aromaticity regions. Five component parallel factor (PARAFAC) modeling of EEM afforded: (C1) (poly)phenolic pyrolysis products and other water-soluble aromatic structures similar to fulvic-like SOC; (C2-C3) aromatic structures similar to humic-like SOC having low water solubility that decomposed above 350°C; (C4) carboxyl and other transient thermochemical conversion intermediates that decomposed above 500°C; and (C5) thermally stable DOC fraction of lignin-rich biomass (pecan shell and lignin). Relative contribution of fulvic-like component exceeded that of humic-like components, and increased as a function of pyrolysis temperature. The C4 showed disproportionately high contributions to 500°C broiler litter and cottonseed hull biochars. The carboxyl-enriched DOC of biochars pyrolyzed at 350-500°C can have diverse environmental consequences, including the mobilization of heavy metals.
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