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Polycyclic aromatic hydrocarbons (PAH), soot and light gases formed in the pyrolysis of acetylene at different temperatures. Effect of fuel concentration
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Nazly E. Sánchez, Ángela Millera, Rafael Bilbao, María U. Alzueta
The effect of different inlet hydrocarbon concentrations (10000, 20000 and 30000 ppmv) and reaction temperatures (873-1323K) on PAH and soot formation from acetylene pyrolysis has been studied. 16 PAH considered by Environmental Protection Agency (EPA) as priority pollutants, together with light gases present at the outlet gas stream, have been quantified. Soot formed was collected on a filter at the reactor outlet. PAH found in the different phases (at the gas phase, adsorbed on soot, and/or sticked on reactor walls) were analysed by means of gas chromatography-mass spectrometry (GC-MS). Increasing fuel concentration and reaction temperature resulted in the increase in soot production together with decrease in the light gases at the reactor outlet. The acetylene conversion and the hydrogen concentration increased with the temperature, whereas benzene and the total PAH quantified showed a maximum around 1123 and 1223K, respectively. In all cases, the concentration of products such as hydrogen, benzene, PAH and soot at the reactor outlet and the acetylene conversion increased with the reactant concentration. The temperature, at which the benzene showed a maximum concentration, was similar to the temperature where soot and PAH started to be formed. This suggests that benzene consumption leads to form PAH, which subsequently form soot, by following the well-known HACA (hydrogen abstraction/acetylene addition) mechanism.
Source:Journal of Analytical and Applied Pyrolysis
Nazly E. Sánchez, Ángela Millera, Rafael Bilbao, María U. Alzueta
The effect of different inlet hydrocarbon concentrations (10000, 20000 and 30000 ppmv) and reaction temperatures (873-1323K) on PAH and soot formation from acetylene pyrolysis has been studied. 16 PAH considered by Environmental Protection Agency (EPA) as priority pollutants, together with light gases present at the outlet gas stream, have been quantified. Soot formed was collected on a filter at the reactor outlet. PAH found in the different phases (at the gas phase, adsorbed on soot, and/or sticked on reactor walls) were analysed by means of gas chromatography-mass spectrometry (GC-MS). Increasing fuel concentration and reaction temperature resulted in the increase in soot production together with decrease in the light gases at the reactor outlet. The acetylene conversion and the hydrogen concentration increased with the temperature, whereas benzene and the total PAH quantified showed a maximum around 1123 and 1223K, respectively. In all cases, the concentration of products such as hydrogen, benzene, PAH and soot at the reactor outlet and the acetylene conversion increased with the reactant concentration. The temperature, at which the benzene showed a maximum concentration, was similar to the temperature where soot and PAH started to be formed. This suggests that benzene consumption leads to form PAH, which subsequently form soot, by following the well-known HACA (hydrogen abstraction/acetylene addition) mechanism.
Effect of nano Ni-Fe alloy addition on flash pyrolysis of poly(ethylene glycol)
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Z.K. Lin, D.L. Han, S.F. Li
Flash pyrolysis of p-PEG (pure PEG) and PEG/NiFe (mixture of PEG and nano Ni-Fe alloy) was carried out in argon atmosphere, aiming to study the effect of nano Ni-Fe alloy on the behavior and mechanism of PEG pyrolysis. A special combinational system was designed to perform pyrolysis experiment and collect pyrolysis products, while GC/MS was employed to identify the products. The experimental results showed that nano Ni-Fe alloy changed not only the relative contents but also the series of PEG pyrolysis products. It was interesting that all of 15 possible series of PEG pyrolysis products in theory were detected from p-PEG and/or PEG/NiFe pyrolysis in the present work. Six product series disappeared and two new product series were detected after adding nano Ni-Fe alloy. Based on quantitative analysis of the end groups of products, the effect of nano Ni-Fe alloy on PEG pyrolysis process as well as the mechanism was discussed. Ni and Fe played quite different roles in the process of PEG pyrolysis. Fe made end group -O-CH2-CH3, -O-CH=CH2, -OH and -O-CH3 transfer to -O-CH2-CHO by inducting hydrogen transfer and O-C bond cleavage; Ni made -O-CH=CH2 transfer to -O-CH2-CH3 by inducting hydrogenation.
Source:Journal of Analytical and Applied Pyrolysis
Z.K. Lin, D.L. Han, S.F. Li
Flash pyrolysis of p-PEG (pure PEG) and PEG/NiFe (mixture of PEG and nano Ni-Fe alloy) was carried out in argon atmosphere, aiming to study the effect of nano Ni-Fe alloy on the behavior and mechanism of PEG pyrolysis. A special combinational system was designed to perform pyrolysis experiment and collect pyrolysis products, while GC/MS was employed to identify the products. The experimental results showed that nano Ni-Fe alloy changed not only the relative contents but also the series of PEG pyrolysis products. It was interesting that all of 15 possible series of PEG pyrolysis products in theory were detected from p-PEG and/or PEG/NiFe pyrolysis in the present work. Six product series disappeared and two new product series were detected after adding nano Ni-Fe alloy. Based on quantitative analysis of the end groups of products, the effect of nano Ni-Fe alloy on PEG pyrolysis process as well as the mechanism was discussed. Ni and Fe played quite different roles in the process of PEG pyrolysis. Fe made end group -O-CH2-CH3, -O-CH=CH2, -OH and -O-CH3 transfer to -O-CH2-CHO by inducting hydrogen transfer and O-C bond cleavage; Ni made -O-CH=CH2 transfer to -O-CH2-CH3 by inducting hydrogenation.
Highlights
► Flash pyrolysis of pure PEG and PEG/Ni-Fe was studied in argon atmosphere. ► A special combinational system was designed to perform pyrolysis experiment and collect pyrolysis products. ► Nano Ni-Fe alloy changed relative contents and series of PEG pyrolysis products. ► The mechanism about effect of nano Ni-Fe alloy on PEG pyrolysis was discussed.Co-gasification of crude glycerol with lignocellulosic biomass for enhanced syngas production
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Vassiliki K. Skoulou, Anastasia A. Zabaniotou
The present work concerns the co-gasification of crude glycerol (CG), a by-product of biodiesel industry, with locally available lignocellulosic biomass aiming at the production of syngas and further promotion of power production in dedicated bioenergy units. Co-gasification of CG with olive kernel (OK), an agro-residue issued from the intensive olive oil production sector in Southern East Europe, was performed in a laboratory fixed bed reactor at T=750-850οC with λ=0.2-0.4 and in the three different mixing levels of 24 wt%, 32 wt% and 49 wt% CG in OK. Co-gasification of CG with OK found to favor the gas yield which increased from 0.4 up to 1.2 Nm3/kg for the mixture of 49wt% of CG in biomass. Additionally H2 concentration increased from 19 to 33%vv in the gasification gas while the tar yield decreased from 19.5 to 2.4 wt% at conditions of T=850οC and λ=0.4.
Source:Journal of Analytical and Applied Pyrolysis
Vassiliki K. Skoulou, Anastasia A. Zabaniotou
The present work concerns the co-gasification of crude glycerol (CG), a by-product of biodiesel industry, with locally available lignocellulosic biomass aiming at the production of syngas and further promotion of power production in dedicated bioenergy units. Co-gasification of CG with olive kernel (OK), an agro-residue issued from the intensive olive oil production sector in Southern East Europe, was performed in a laboratory fixed bed reactor at T=750-850οC with λ=0.2-0.4 and in the three different mixing levels of 24 wt%, 32 wt% and 49 wt% CG in OK. Co-gasification of CG with OK found to favor the gas yield which increased from 0.4 up to 1.2 Nm3/kg for the mixture of 49wt% of CG in biomass. Additionally H2 concentration increased from 19 to 33%vv in the gasification gas while the tar yield decreased from 19.5 to 2.4 wt% at conditions of T=850οC and λ=0.4.
Thermal Degradation of Poly(isobornyl acrylate) and Its Copolymer with Poly(methyl methacrylate) via Pyrolysis Mass Spectrometry
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Suriye Ozlem, Evren Aslan-Gürel, Rene M. Rossi, Jale Hacaloglu
In this work, the thermal degradation characteristics of poly(isobornyl acrylate) (PIBA), and its copolymer with PMMA, P(MMA-co-IBA) were investigated via direct pyrolysis mass spectrometry. Thermal degradation behavior of poly(isobornyl methacrylate) (PIBMA) was also studied for a better understanding of thermal degradation mechanism of PIBA. For both PIBA and PIBMA, γ-H transfer from the isobornyl ring to the carbonyl group was predominantly effective in thermal degradation. As a consequence of evolution of isoborylene, poly(acrylic acid) was produced. Trans-esterification reactions due to intermolecular interactions lead to evolution of H2O. Upon loses of CO2 and CO crosslinked units with higher thermal stabilities were generated. In case of P(MMA-co-IBA), intermolecular interactions between PIBA and PMMA chains were detected. Based on evolution of methanol, a trans-esterification reaction between the MMA and acrylic acid units generated by loss of isobornylene from PIBA chains was proposed.
Source:Journal of Analytical and Applied Pyrolysis
Suriye Ozlem, Evren Aslan-Gürel, Rene M. Rossi, Jale Hacaloglu
In this work, the thermal degradation characteristics of poly(isobornyl acrylate) (PIBA), and its copolymer with PMMA, P(MMA-co-IBA) were investigated via direct pyrolysis mass spectrometry. Thermal degradation behavior of poly(isobornyl methacrylate) (PIBMA) was also studied for a better understanding of thermal degradation mechanism of PIBA. For both PIBA and PIBMA, γ-H transfer from the isobornyl ring to the carbonyl group was predominantly effective in thermal degradation. As a consequence of evolution of isoborylene, poly(acrylic acid) was produced. Trans-esterification reactions due to intermolecular interactions lead to evolution of H2O. Upon loses of CO2 and CO crosslinked units with higher thermal stabilities were generated. In case of P(MMA-co-IBA), intermolecular interactions between PIBA and PMMA chains were detected. Based on evolution of methanol, a trans-esterification reaction between the MMA and acrylic acid units generated by loss of isobornylene from PIBA chains was proposed.
Highlights
► Evolution of isoborylene during the degradation of PIBA generates poly(acrylic acid). ► Poly(acrylic acid) decomposes by trans-esterification reactions eliminating H2O. ► Intermolecular interactions between PIBA and PMMA are effective.Preliminary Laboratory Production and Characterization of Biochars from Lignocellulosic Municipal Waste
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Perry J. Mitchell, Travis S.L. Dalley, Robert J. Helleur
Converting lignocellulosic municipal waste to biochar represents a carbon sequestration mechanism and a production route that diverts potentially useful feedstocks from landfills. In this preliminary investigation, slow pyrolysis to 480°C was used to produce biochars from eighteen different wastes which were characterized by proximate analysis to determine ash, volatile matter and fixed carbon content. Desirable soil amendment properties such as cation exchange and gas adsorption capacities and pH were also measured. Pristine wood and several closely related products exhibited low ash and high fixed carbon content while paper and cardboard products were found to have higher ash and volatile matter content. Cation exchange capacity (CEC) values were comparable to activated carbon (AC) and within a similar range for most feedstock biochars, with grass and cardboard biochars having the highest CEC. All biochars were found to have similar gas adsorption capacities (GAC) that were lower than AC while newsprint biochar had a GAC twice as high as other samples. All biochars showed neutral to slightly alkaline pH values. In general, lignocellulosic municipal waste biochars exhibited a diverse range of potentially beneficial properties and should be further investigated as prospective soil amendments.
Source:Journal of Analytical and Applied Pyrolysis
Perry J. Mitchell, Travis S.L. Dalley, Robert J. Helleur
Converting lignocellulosic municipal waste to biochar represents a carbon sequestration mechanism and a production route that diverts potentially useful feedstocks from landfills. In this preliminary investigation, slow pyrolysis to 480°C was used to produce biochars from eighteen different wastes which were characterized by proximate analysis to determine ash, volatile matter and fixed carbon content. Desirable soil amendment properties such as cation exchange and gas adsorption capacities and pH were also measured. Pristine wood and several closely related products exhibited low ash and high fixed carbon content while paper and cardboard products were found to have higher ash and volatile matter content. Cation exchange capacity (CEC) values were comparable to activated carbon (AC) and within a similar range for most feedstock biochars, with grass and cardboard biochars having the highest CEC. All biochars were found to have similar gas adsorption capacities (GAC) that were lower than AC while newsprint biochar had a GAC twice as high as other samples. All biochars showed neutral to slightly alkaline pH values. In general, lignocellulosic municipal waste biochars exhibited a diverse range of potentially beneficial properties and should be further investigated as prospective soil amendments.
Highlights
► Biochars were produced from lignocellulosic municipal waste by slow pyrolysis. ► Proximate and elemental analyses were conducted for all biochars. ► Cation exchange and gas adsorption capacities and pH were also measured. ► Woody plant tissue and low-processed paper biochars were similar to wood biochars. ► High ash content biochars result from highly processed paper and cardboard feedstocks.Solid state synthesis, thermodynamics and catalytic combustion effect of a high energy nickel(II) coordination compound
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Qi Yang, Qing Wei, San-Ping Chen, Guo-Chun Zhang, Chun-Sheng Zhou, Sheng-Li Gao
Self-assembly of Ni(II) with 3,5-diamino-1,2,4-triazole resulted in a 3D supramolecular compound [Ni3(Hdatrz)6(fma)2(H2O)4]fma·11H2O (1) in the presence of coligand fumaric acid (Hdatrz=3,5-diamino-1,2,4-triazole, H2fma=fumaric acid). X-ray structural analysis reveals that three nickel ions are bridged by six neutral Hdatrz ligands, and abundant lattice water molecules exist in 1. Based on the structural framework and TG curve of 1, a new energetic compound [Ni3(Hdatrz)6(fma)2(H2O)4]fma (2) with 35.5% of nitrogen content was readily prepared through dehydration of 1 at 398K under N2 atmosphere. The enthalpy change of the reaction of formation for 1 was determined to be (-23.24 ± 0.05) kJ·mol-1 by microcalorimetry at (298.15 ± 0.01) K. Thermodynamic and thermokinetic parameters k, E, n, Δ S ≠ θ , Δ H ≠ θ and Δ G ≠ θ of the reaction of formation for 1 were obtained. Thermoanalytical kinetics of the reaction of formation for 2 was further investigated. The sensitivity experiment results indicated that 2 was more sensitive to impact and friction stimuli that 1. As an additive, 2 effectively promoted the thermal decomposition of ammonium perchlorate (AP), which projected the potential application of the compound 2 as combustion modifier in solid propellants.
Source:Journal of Analytical and Applied Pyrolysis
Qi Yang, Qing Wei, San-Ping Chen, Guo-Chun Zhang, Chun-Sheng Zhou, Sheng-Li Gao
Self-assembly of Ni(II) with 3,5-diamino-1,2,4-triazole resulted in a 3D supramolecular compound [Ni3(Hdatrz)6(fma)2(H2O)4]fma·11H2O (1) in the presence of coligand fumaric acid (Hdatrz=3,5-diamino-1,2,4-triazole, H2fma=fumaric acid). X-ray structural analysis reveals that three nickel ions are bridged by six neutral Hdatrz ligands, and abundant lattice water molecules exist in 1. Based on the structural framework and TG curve of 1, a new energetic compound [Ni3(Hdatrz)6(fma)2(H2O)4]fma (2) with 35.5% of nitrogen content was readily prepared through dehydration of 1 at 398K under N2 atmosphere. The enthalpy change of the reaction of formation for 1 was determined to be (-23.24 ± 0.05) kJ·mol-1 by microcalorimetry at (298.15 ± 0.01) K. Thermodynamic and thermokinetic parameters k, E, n, Δ S ≠ θ , Δ H ≠ θ and Δ G ≠ θ of the reaction of formation for 1 were obtained. Thermoanalytical kinetics of the reaction of formation for 2 was further investigated. The sensitivity experiment results indicated that 2 was more sensitive to impact and friction stimuli that 1. As an additive, 2 effectively promoted the thermal decomposition of ammonium perchlorate (AP), which projected the potential application of the compound 2 as combustion modifier in solid propellants.
Highlights
► A new energetic compound 2 was prepared via thermo-dehydration of compound 1. ► Thermodynamics and thermokinetics for both compounds were investigated. ► 2 was more sensitive than 1, which would provide an insight for storage of high-energy materials. ► 2 efficiently accelerated the thermal decomposition of AP.m2.Thermal behavior and gaseous emission analysis during co-combustion of ethanol fermentation residue from food waste and coal using TG-FTIR
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Wei Su, Hongzhi Ma, Qunhui Wang, Jin Li, Jingyi Ma
Thermal characteristics and kinetics of coal and fermentation residue from food waste, including their blends, were evaluated using a non-isothermal thermogravimetric method (TGA). The ratio of fermentation residue to the blends by mass was set as 1/6, 2/6, 3/6, 4/6, and 5/6. The sample with 4/6 ratio exhibited the lowest final temperature and highest complex burning index of 2.24×10−6 °C−3·min−2, which was determined as the optimum ratio. The kinetic analysis demonstrated that the first-order and phase-boundary-controlled reaction models could well describe the burning process with higher correlation index. The gaseous emission analysis by using the coupled fourier transform infrared (FTIR) measurements were used for HCl, SO2, CO2. The results for the sample with ration of 4/6 demonstrated that HCl and SO2 decreased much more than those other ratio, which indicated that the blends could be regarded as an environmental-friendly fuel.
Source:Journal of Analytical and Applied Pyrolysis
Wei Su, Hongzhi Ma, Qunhui Wang, Jin Li, Jingyi Ma
Thermal characteristics and kinetics of coal and fermentation residue from food waste, including their blends, were evaluated using a non-isothermal thermogravimetric method (TGA). The ratio of fermentation residue to the blends by mass was set as 1/6, 2/6, 3/6, 4/6, and 5/6. The sample with 4/6 ratio exhibited the lowest final temperature and highest complex burning index of 2.24×10−6 °C−3·min−2, which was determined as the optimum ratio. The kinetic analysis demonstrated that the first-order and phase-boundary-controlled reaction models could well describe the burning process with higher correlation index. The gaseous emission analysis by using the coupled fourier transform infrared (FTIR) measurements were used for HCl, SO2, CO2. The results for the sample with ration of 4/6 demonstrated that HCl and SO2 decreased much more than those other ratio, which indicated that the blends could be regarded as an environmental-friendly fuel.
Highlights
► TG-FTIR for ethanol fermentation residue mixed with coal. ► Optimum mixture ratio and pollution emission characteristic was analyzed. ► Kinetic analysis determined the model for the two stage combustion process.Bromine fixation by metal oxide in pyrolysis of printed circuit board containing brominated flame retardant
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
O. Terakado, R. Ohhashi, M. Hirasawa
Pyrolysis study of a printed circuit board (FR-4 type, epoxy resin reinforced by glass fibres) under the presence of metal oxide, such as ZnO, Fe2O3, La2O3, CaO and CuO, has been carried out in the view of the emission control of wastes of electric and electronic equipment (WEEE) containing brominated flame retardants by metallurgical wastes like slags and dusts. The oxide content is of 2-10 mass % to the printed circuit board on the basis of the stoichiometric reaction of oxide and bromine to the corresponding metal bromide or oxybromide. It has been revealed that the formation of hydrogen bromide and brominated organic compounds is significantly suppressed by the addition of ZnO and La2O3. The bromine fixation ability of various oxides is compared and discussed.
Source:Journal of Analytical and Applied Pyrolysis
O. Terakado, R. Ohhashi, M. Hirasawa
Pyrolysis study of a printed circuit board (FR-4 type, epoxy resin reinforced by glass fibres) under the presence of metal oxide, such as ZnO, Fe2O3, La2O3, CaO and CuO, has been carried out in the view of the emission control of wastes of electric and electronic equipment (WEEE) containing brominated flame retardants by metallurgical wastes like slags and dusts. The oxide content is of 2-10 mass % to the printed circuit board on the basis of the stoichiometric reaction of oxide and bromine to the corresponding metal bromide or oxybromide. It has been revealed that the formation of hydrogen bromide and brominated organic compounds is significantly suppressed by the addition of ZnO and La2O3. The bromine fixation ability of various oxides is compared and discussed.
Highlights
► A printed circuit board is pyrolysed under the presence of metal oxide. ► Examined oxides include ZnO, Fe2O3, La2O3, CaO and CuO. ► The oxide content is of 2-10 mass % to the printed circuit board. ► ZnO and La2O3 suppress the yield of HBr and brominated organic compounds. ► The mechanism is considered as the reaction of oxide and flame retardants.Microporous activated carbon from Siris seed pods by microwave-induced KOH activation for metronidazole adsorption
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Muthanna J. Ahmed, Samar K. Theydan
In this study, microwave-assisted KOH activation was adopted for preparation of a microporous activated carbon from an agricultural waste, Siris seed pods. Carbon with high BET surface area of 1824.88 m2/g and 0.782cm3/g total pore volume has been obtained from these precursors. The influences of radiation time, radiation power, and impregnation ratio on yield and iodine number of prepared carbon have been studied and the best conditions were determined. The sorption mechanisms of a nitroimidazole antibiotic, metronidazole (MNZ), onto such carbon have been investigated. The adsorption data of MNZ were analyzed by Langmuir, Freundlich, and Temkin isotherms and the best correlation was achieved by the Langmuir isotherm with maximum capacity of 196.31mg/g. The analyses of kinetic data showed that the adsorption of MNZ on prepared carbon follow closely the pseudo-second order model. Results of thermodynamic studies showed endothermic and spontaneous natures of MNZ adsorption under examined conditions.
Source:Journal of Analytical and Applied Pyrolysis
Muthanna J. Ahmed, Samar K. Theydan
In this study, microwave-assisted KOH activation was adopted for preparation of a microporous activated carbon from an agricultural waste, Siris seed pods. Carbon with high BET surface area of 1824.88 m2/g and 0.782cm3/g total pore volume has been obtained from these precursors. The influences of radiation time, radiation power, and impregnation ratio on yield and iodine number of prepared carbon have been studied and the best conditions were determined. The sorption mechanisms of a nitroimidazole antibiotic, metronidazole (MNZ), onto such carbon have been investigated. The adsorption data of MNZ were analyzed by Langmuir, Freundlich, and Temkin isotherms and the best correlation was achieved by the Langmuir isotherm with maximum capacity of 196.31mg/g. The analyses of kinetic data showed that the adsorption of MNZ on prepared carbon follow closely the pseudo-second order model. Results of thermodynamic studies showed endothermic and spontaneous natures of MNZ adsorption under examined conditions.
Highlights
► Microporous carbon with BET surface area of 1824.88 m2/g was prepared. ► Siris seed pods were used as precursors. ► Microwave technique was adopted for preparation using KOH. ► Sorption mechanisms of metronidazole antibiotic MNZ was illustrated. ► Maximum capacity of 196.31mg/g was reported for MNZ.Analytical pyrolysis as an instrument to study the chemical transformations of hydrothermally modified wood
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Juris Grinins, Bruno Andersons, Vladimirs Biziks, Ingeborga Andersone, Galina Dobele
In the present study, changes in the chemical structure of the components of deciduous wood species, i.e., birch (Betula spp.), aspen (Populus tremula) and grey alder (Alnus incana) wood, after hydrothermal modification (HTM) were investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and wet chemical analysis. The objective of this study was to elucidate the chemical changes in HTM deciduous wood dependent on the treatment parameters using chemical analysis and analytical pyrolysis and to evaluate the differences between the tree species. The results of both chemical and analytical pyrolysis studies demonstrate the effect of HTM on the chemical composition of deciduous wood. Wet chemical analyses showed that the hemicellulose content in wood decreased considerably (by 60-75%), whereas the cellulose and lignin contents increased by 6-20% and ∼50%, respectively. The thermal destruction of hemicelluloses during HTM was also indicated by the water condensates, which contained acids and sugars. As a result of the HTM, wood transitions from a solid state to an aggregate state, in which the chemical composition of the gases (gas mixture) depends on the chemical composition of the wood. Py-GC/MS can quantitatively and promptly detect changes in the chemical composition of wood after HTM. As a result of the high HTM of wood above 160°C, hemicelluloses are thermochemically destroyed and the primary products are acids (e.g., acetic acid and formic acid). Cellulose and lignin are more thermally stable than the hemicelluloses, as evidenced by the analytical pyrolysis results, which showed that the hemicellulose content in the wood decreased and the lignin content increased by revealing that the acid, ester and ether content in the gases decreased (by 24-33%) and the guaiacyl and syringyl derivative content increased (by 5-7%). Analytical pyrolysis is a promising method for understanding chemical transformations in HTM wood.
Source:Journal of Analytical and Applied Pyrolysis
Juris Grinins, Bruno Andersons, Vladimirs Biziks, Ingeborga Andersone, Galina Dobele
In the present study, changes in the chemical structure of the components of deciduous wood species, i.e., birch (Betula spp.), aspen (Populus tremula) and grey alder (Alnus incana) wood, after hydrothermal modification (HTM) were investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and wet chemical analysis. The objective of this study was to elucidate the chemical changes in HTM deciduous wood dependent on the treatment parameters using chemical analysis and analytical pyrolysis and to evaluate the differences between the tree species. The results of both chemical and analytical pyrolysis studies demonstrate the effect of HTM on the chemical composition of deciduous wood. Wet chemical analyses showed that the hemicellulose content in wood decreased considerably (by 60-75%), whereas the cellulose and lignin contents increased by 6-20% and ∼50%, respectively. The thermal destruction of hemicelluloses during HTM was also indicated by the water condensates, which contained acids and sugars. As a result of the HTM, wood transitions from a solid state to an aggregate state, in which the chemical composition of the gases (gas mixture) depends on the chemical composition of the wood. Py-GC/MS can quantitatively and promptly detect changes in the chemical composition of wood after HTM. As a result of the high HTM of wood above 160°C, hemicelluloses are thermochemically destroyed and the primary products are acids (e.g., acetic acid and formic acid). Cellulose and lignin are more thermally stable than the hemicelluloses, as evidenced by the analytical pyrolysis results, which showed that the hemicellulose content in the wood decreased and the lignin content increased by revealing that the acid, ester and ether content in the gases decreased (by 24-33%) and the guaiacyl and syringyl derivative content increased (by 5-7%). Analytical pyrolysis is a promising method for understanding chemical transformations in HTM wood.
Highlights
► Hydrothermal modification–modification in a saturated steam environment at superatmospheric pressure. ► The relative amount of hemicelluloses in the modified wood decreases, but that of cellulose and lignin increases. ► Hemicelluloses–the most thermally unstable component of the cell wall. ► Water condensate–a mixture of the products of thermal destruction of hemicelluloses. ► In lignin pyrolysis products, the content of compounds with a short aliphatic chain increases.Fluidised bed pyrolysis of lignocellulosic biomasses and comparison of bio-oil and micropyrolyser pyrolysate by GC/MS-FID
14 November 2012,
10:49:28
Publication year:
2012
Source:Journal of Analytical and Applied Pyrolysis
Eoin Butler, Ger Devlin, Dietrich Meier, Kevin McDonnell
The fast pyrolysis of Spruce (Picea abies), short rotation willow coppice (Salix alba), Miscanthus (Miscanthus x giganteus), and wheat straw (Triticum aestivum) was compared on a laboratory scale bubbling fluidized bed reactor at 460-475°C. The presence of ash, ranging from 0.26wt. % for spruce to 3.76wt. % for wheat straw (moisture free basis) favoured decomposition of cell-wall constituents to char (spruce [11.4wt. %]< Salix [16.2wt. %]< Miscanthus [21.8wt. %]<wheat straw [21.5wt. %]) with a reduction of liquid organic product (spruce [53.8wt. %]> Salix [45.4wt. %]> Miscanthus [37.3wt. %]> wheat straw [37.2wt. %]). Bio-oils from Miscanthus and wheat straw were inhomogeneous. Differences between absolute masses of compounds determined by GC/MS-FID of the bio-oils compared with Py-GC/MS-FID suggested a greater role of secondary reactions at the fluidised bed scale, with reduced concentrations of certain lignin-derived, furan and pyran compounds.
Source:Journal of Analytical and Applied Pyrolysis
Eoin Butler, Ger Devlin, Dietrich Meier, Kevin McDonnell
The fast pyrolysis of Spruce (Picea abies), short rotation willow coppice (Salix alba), Miscanthus (Miscanthus x giganteus), and wheat straw (Triticum aestivum) was compared on a laboratory scale bubbling fluidized bed reactor at 460-475°C. The presence of ash, ranging from 0.26wt. % for spruce to 3.76wt. % for wheat straw (moisture free basis) favoured decomposition of cell-wall constituents to char (spruce [11.4wt. %]< Salix [16.2wt. %]< Miscanthus [21.8wt. %]<wheat straw [21.5wt. %]) with a reduction of liquid organic product (spruce [53.8wt. %]> Salix [45.4wt. %]> Miscanthus [37.3wt. %]> wheat straw [37.2wt. %]). Bio-oils from Miscanthus and wheat straw were inhomogeneous. Differences between absolute masses of compounds determined by GC/MS-FID of the bio-oils compared with Py-GC/MS-FID suggested a greater role of secondary reactions at the fluidised bed scale, with reduced concentrations of certain lignin-derived, furan and pyran compounds.
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