Inhibition Effect of Ammonium Dihydrogen Phosphate on the Thermal Decomposition Characteristics and Thermal Sensitivity of Ammonium Nitrate J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-15 Man Yang, Xianfeng Chen, Bihe Yuan, Yujie Wang, Ali S. Rangwala, Huiqi Cao, Yi Niu, Ying Zhang, Ao Fan, Shuhui Yin
In order to analyze the inhibition effect of the additive on the thermal decomposition characteristics of ammonium nitrate (AN), thermal stability and thermal decomposition behavior of AN and its mixtures with various concentrations of ammonium dihydrogen phosphate (ADP) are systematically investigated by DSC-TG, DSC-TG-QMS and TG-FTIR. Breaking point value of the samples is obtained as an evaluation parameter for thermal safety. Experimental results show that the AN-ADP mixtures show higher onset decomposition temperatures, narrower reaction temperature region and lower enthalpy values than those of pure AN. The main evolved decomposition gases of AN are NH3, H2O, NO, N2O, NO2 and HNO3, while the major gaseous products of the AN mixture with ADP are NH3, H2O, NO, N2O and NO2. Furthermore, the generation of NO and NO2 is obviously postponed in the AN mixture. In addition, the breaking point value of AN is markedly improved by ADP. The decomposition mechanism of AN-ADP mixture is concluded and the inhibition mechanism of ADP is proposed. It is concluded that ADP is an effective inhibitor for AN and its thermal stability is effectively enhanced.
Segmented catalytic co-pyrolysis of biomass and high-density polyethylene for aromatics production with MgCl2 and HZSM-5 J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-13 Xiangfei Xue, Zeyou Pan, Changsen Zhang, Dengtai Wang, Yunyun Xie, Ruiqin Zhang
Improvement of pyrolysis oil obtained from co-pyrolysis of WPCBs and compound additive during two stage pyrolysis J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-13 Ziwei Ye, Fan Yang, Weixiong Lin, Shuiyu Sun
In order to improve the combustion of pyrolysis oil, recovery of low brominated and lightweight oil was investigated through the pyrolysis of waste printed circuit boards (WPCBs) with the addition of Fe3O4 and 4 A. Variations in the pyrolysis process were studied via by analyses of TG/MS data, three-phase pyrolysis product distributions, organic bromine content, oil content and heat value (HV), the number distribution of carbon atoms and oil composition of experimental product fractions. Results show that the pyrolysis of WPCBs can be divided into three stages: evaporation stage (≤280℃), decomposition stage (280~500℃) and stabilization stage (≥500℃), according to the TG/DTG curve. Phenol, 2-methyl phenol, and 2,6-dimethyl phenol were the major products based on the MS data. The liquid product and HV were up to 30% and 33.27 MJ/kg, respectively, and the organic bromine content was reduced to 10.45 mg/g. Moreover, the number distribution of carbon atoms showed that the oil had more C6, C9 and C12 fractions, and less C15 fraction. The main components of oil were phenol, phenol,4-(1-methylethyl)-, and phenol,4,4'-(1-methylethylidene)bis-. The oil produced in this way has more potential in combustion and other fields.
Waste and Virgin high-density poly(ethylene) into Renewable Hydrocarbons Fuel by pyrolysis-catalytic cracking with a CoCO3 Catalyst J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-12 Man Vir Singh
Conversion of waste and virgin high-density poly(ethylene) (HD-PE) into renewable fuel/petrochemicals were carried out using a basic cobalt carbonate (CoCO3) catalysts by a pyrolysis-catalytic cracking process. The pyrolysis-catalytic cracking process provides an alternative clean fuel and also minimizes to the environmental problems by waste plastics. Renewable hydrocarbons fuel were analyzed by 2D-GC × GC/TOFMS, FT-IR spectroscopy, 1H NMR spectroscopy, CHNS/O analyzer, inductively coupled plasma (ICP) and its results found absolutely good hydrocarbon compounds as (in fuel were petrochemicals obtained from virgin plastic and waste HD-PE). Catalytic conversion rates of four experiments as virgin HD-PE into renewable hydrocarbons fuel was found 80%, 84.40%, 88.22%, 92 %, light gases 19.69%, 15.35%, 11.53%, 7.77%, residues 0.31%, 0.28%, 0.25%, 0.30 recovered from the overall production. Catalytic conversion rates of four experiments as waste HD-PE into renewable hydrocarbons fuel was found 79%, 82%, 84%, 91 %, light gases 20.50%, 17.55%, 15.65%, 8.59%, residues 0.50%, 0.49%, 0.35%, 0.41. Renewable hydrocarbon fuel was analyzed using ICP for sulfur contents, it was found very low sulfur content than ordinary fuel. It was observed that it is the only degradation of virgin and waste HD-PE but not creating any other reactions.
Thermal Degradation of Flame-retarded high-voltage Cable Sheath and Insulation via TG-FTIR J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-05 Changjian Wang, Haoran Liu, Jiaqing Zhang, Shenlin Yang, Zhi Zhang, Weiping Zhao
In energy application system, electrical energy is economic, practical, clean and easy to control and transfer. Electrical cables, especially high-voltage cables have been extensively and increasingly applied in industries, and however their fire safety deserves more attention. Thermal behaviours of flame-retarded high-voltage Cable Sheath and Insulation were studied using SDT Q600 thermal analyser. The cable sheath pyrolysis profiles show three peaks while the insulation has only one peak. Possible reaction pathways and activation energy evolution with various conversion rate were analysed using both model-free and model-fitting methods. Evolved gas analysis by Fourier transform infrared spectroscopy (FTIR) shows that the amount of six main components produced in the order of most to least is CO2> C-H stretching > C-H bending > C-H aliphatic bending > CH2 deformation > C-Cl stretching for cable sheath while the relationship of C-H stretching > C-H scissor vibration > CO2 > C = O & C = C stretching is determined for the cable insulation.
Catalytic mechanism of sulfuric acid in cellulose pyrolysis: A combined experimental and computational investigation J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-05 Bin Hu, Qiang Lu, Yu-ting Wu, Zhen-xi Zhang, Min-shu Cui, Ding-jia Liu, Chang-qing Dong, Yong-ping Yang
Enhanced corrosion resistance and antibacterial activity of Zn-HA decorated MWCNTs film coated on medical grade 316L SS implant by novel spray pyrolysis technique J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-04 D. Sivaraj, K. Vijayalakshmi
With the increase of bioimplants surgery, there is need to develop the new bioactive materials with good antibacterial activity and corrosion resistance of implants made of stainless steel. In the present work, we report the bioactivity of HA/CNT and the hybrid Zn-HA/MWCNT thin films prepared on medical grade 316 L SS substrate by spray pyrolysis technique. The coated films were characterized using X-ray diffraction, FTIR, and FE-SEM. The structural analysis of the film shows change in the lattice parameter and crystallite size after Zn addition into the HA/MWCNT composite. The shifting in the FTIR spectra at the range of 400- 900 cm-1 confirms the successful doping of Zn. SEM micrograph shows the transformation of spherical HA particle to hexagonal rod like particle bundled around the carbon nanotubes beneficial for bioimplant applications. Gram negative bacteria revealed higher zone of inhibition of 16 mm for zinc substituted sample compared with the value of 13 mm recorded for with HA/MWCNT. Potentialdynamic polarisation spectra of the hybrid Zn-HA/MWCNT coated implant revealed a higher Ecorr and Icorr values of −278 mV and 4.2 µA compared to bare HA/MWCNT. The polarisation and antibacterial study confirms that the Zn modified HA/MWCNT coated implant prevents the formation of bio-film, bacterial adhesion and release of metal ions from the implant.
Thermal pretreatment of a high lignin SSF digester residue to increase its softening point J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2016-03-24 Daniel Howe, Manuel Garcia-Perez, Danny Taasevigen, James Rainbolt, Karl Albrecht, Hui Li, Liqing Wei, Armando McDonald, Michael Wolcott
Residues high in lignin and ash generated from the simultaneous saccharification and fermentation of corn stover were thermally pretreated in an inert (N2) atmosphere to study the effect of time and temperature on their softening points. These residues are difficult to feed into gasifiers due to premature thermal degradation and formation of reactive liquids in the feed lines, leading to plugging. The untreated and treated residues were characterized by proximate and ultimate analysis, and then analyzed via TGA, DSC, 13C NMR, Py-GC–MS, CHNO/S, and TMA. Interpretation of the compositional analysis indicates that the weight loss observed during pretreatment is mainly due to the thermal decomposition and volatilization of the hemicelluloses and amorphous cellulose fractions. Fixed carbon increases in the pretreated material, mostly due to a concentration effect rather than the formation of new extra poly-aromatic material. The optimal processing time and temperature to minimize the production of carbonyl groups in the pretreated samples was 300 °C at a time of 30 min. Results showed that the softening point of the material could be increased from 187 °C to 250 °C, and that under the experimental conditions studied, pretreatment temperature plays a more important role than time. The increase in softening point was mainly due to the formation of covalent bonds in the lignin structures and the removal of low molecular weight volatile intermediates.
Study on molecular structure and property of highly purified natural rubber J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-01 Bei L. Zhang, Hong H. Huang, Yong Z. Wang, Li Ding, Yue Liang
The molecular structure, mechanical property and dynamic mechanics performance of highly purified natural rubber (highly purified NR) were studied. The FTIR results showed that there was no stretching vibration absorption peak of N-H group on 3280 cm-1 and vibration compound peak of C-N group and N-H group in amide group on 1540 cm-1 in highly purified NR compared to natural rubber (NR). The pyrolytic products of highly purified NR are less than that of NR. The main pyrolytic products of highly purified NR are limonene, 1,3-pentadiene and 4-ethenyl-1,4-dimethyl-cyclohexene, which contained 58.98% of the total pyrolytic products by mass fraction. Curing time t90 of highly purified NR prolonged, and crosslinking density and tensile strength decreased. Elongation at break increased and anti-aging performance significantly decreased compared to NR. Dynamic mechanics performance of highly purified NR is rather different from that of NR.
Contribution of single coal property to the changes of structure and reactivity of chars from blending coking J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-06-01 Haili Jiao, Meijun Wang, Jiao Kong, Dong Yan, Jiang Guo, Liping Chang
This study investigates the contribution of single coal in blends on the properties of the char produced. Three kinds of coals with varying rank and caking ability were used for the preparation of the chars at 1150 °C in muffle furnace. Char reactivity towards carbon dioxide (CRI) and char strength after reaction (CSR) were tested through the fixed-bed reactor in a laboratory scale and the tumbler, respectively. X-ray diffraction (XRD), scanning electron microscope (SEM), and nitrogen adsorption test were applied to obtain the information for the chemical and physical structures of the char. The study results show that the CRI of char increases with the increase of subbituminous coal content in blends for its role in increasing the surface area and decreasing the crystallite height (Lc) of the chars; the increase of fat coal content in coal blends causes the decrease of the CRI of chars for its contribution to the more ordered crystallite structure and less surface area. The contribution of single coal property in blends to the CSR of chars is just contrary compared to its contribution to the CRI of the chars. Coal blends with high volatile yield and low GR.I value would cause higher surface area and lower crystallite height of char. The CRI of the char can be well predicted by GR.I value and volatile yield of the coal blends quantitatively: CRI(%)=-0.029GR.I+1.995Vdaf−57.937CRI(%)=-0.029GR.I+1.995Vdaf−57.937, which is of certain theoretical guiding significance for gasification of char from coal blends.
Effect of Infrared Laser Radiation on Gas-Phase Pyrolysis of Ethane J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-31 N. Masyuk, A. Sherin, V.N. Snytnikov, Vl.N. Snytnikov
Pyrolysis of hydrocarbons is widely used for the production of light olefins. The pyrolytic processes are energy-consuming, proceeding at high wall reactor temperature and producing large amounts of undesired carbonaceous side-products. There is a demand for the search of lower temperature regimes together with the reduction of side products at high conversion efficiencies. The objective of our research is to decrease the temperature of walls of the pyrolytic reactor for the ethane thermal decomposition by CO2-laser radiation. Gas-phase laser induced pyrolysis of ethane was studied in a continuous flow tubular reactor. Introduction of infrared laser radiation into the pyrolysis reactor results in significant reduction of the reaction temperature threshold and noticeable increase of the ethane conversion at temperatures 870-970 K. At low-temperature range, 760-920 K, significant increase of ethane conversion was observed in the presence of ethylene comprising 5 to 10 % vol. of the initial gas mixture. Similar shift of temperature threshold was also observed with the increase of radiation power density. Analysis of volatile products demonstrated minor differences in the product content for both conventional and laser-induced pyrolysis, thus confirming the laser radiation function as an additional energy source without significant interference in the gas phase reactions. From practical point of view the laser induced pyrolysis opens the possibility to save energy on the account of reduced temperature. The low-temperature pyrolysis could additionally be promoted by the introduction of unsaturated hydrocarbons.
The Thermal Decomposition Mechanism of Irbesartan J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-31 Jin Zong You, Cheng Jie Wu, Xue Jie Wang
Irbesartan (IBS) is an inhibitor of angiotensin II receptor. In order to study the thermal stability and the thermal decomposition mechanism of IBS, the thermal decomposition processes of IBS in nitrogen and in air atmospheres were studied by means of thermogravimetry (TG) and differential scanning calorimetry (DSC), the evolved gaseous products from thermal decomposition were identified with thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR), and the residues of thermal decomposition at various temperatures were analyzed with infrared spectra, high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). The molecular bond orders were calculated by GAMESS program of quantum chemistry, and the thermal decomposition mechanism of IBS was discussed. The results indicated that the thermal decomposition of IBS is a three-stage process and the initial temperatures of the decomposition are 204.7 and 201.0 °C in nitrogen and in air, respectively. The initial step of the decomposition is the partial decomposition of imidazolone and tetrazol sections. The thermal stability of IBS is quite good in the routine temperature.
Thermocatalytic conversion of non-edible Neem seeds towards clean fuel and chemicals J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-29 Ranjeet Kumar Mishra, Kaustubha Mohanty
In this work, a non-edible seed Neem (Azadirachta indica) was used to find out it’s potential to produce fuels and chemicals using thermo-catalytic pyrolysis. The physiochemical characterization confirmed the seed’s bioenergy potential. Thermal and catalytic pyrolysis were carried out at optimum conditions (500 °C temperature, 80 °C min-1 heating rate, 0.5 mm particle size and 80 mL min-1 nitrogen gas flow rate) which produced maximum liquid yield (49.53 wt. % at thermal, 54.06 wt. % and 52.08 wt. % for K2CO3 and Zeolite respectively at Biomass/Catalyst ratio 8:1). The comparative study of thermal and catalytic pyrolytic liquid confirmed that the yield as well as fuel properties of pyrolytic liquid were enhanced with the use of catalysts. It was also noticed that the energy content of gases increased with increasing pyrolysis temperature. Further, with increase in pyrolysis temperature, the amounts of hydrogen and hydrocarbons increased significantly, but at the same time, the formation of carbon dioxide was reduced.
Molecular characterization of digestates from Solid-State Anaerobic Digestion of pig slurry and straw using analytical pyrolysis J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-26 Ornella Cavallo, José María de la Rosa, José Antonio González-Pérez, Heike Knicker, Daniela Pezzolla, Giovanni Gigliotti, Maria Rosaria Provenzano
Straw and pig slurry Solid-State Anaerobic Digestion (SS-AD) was carried out in a pilot-scale apparatus using percolate recirculation technology. The digestion experiments were performed using 1, 2 and 4 recirculations per day; an additional experiment without percolate recirculation was used as control. The initial mixture and the digestates were analysed by means of chemical analyses and Pyrolysis–Gas Chromatography/Mass Spectrometry (Py-GC/MS), a direct analytical technique that allows investigating the changes in the organic matter (OM) composition of digestates and the effect of percolate recirculation frequency. Chemical analyses suggested a positive effect of percolate recirculation on OM degradation. The highest values of OM loss were found with 2 (26%) and 4 (31%) recirculation cycles per day, that also corresponded with the lowest values of the hydrophilic water extractable organic matter fraction (5.5 and 6.3% respectively). Py-GC/MS showed that the anaerobic digestion proceeded with progressive polysaccharide degradation (from c. 19% in the initial mixture to 10-8% with 2-4 recirculation cycles) and selective enrichment of lignin derived compounds (from c. 58% in the initial mixture to 67-69% with 2-4 recirculation cycles). In addition, a shift in the fatty acids distribution was observed with a decrease in the long/short chain ratio of fatty acid methyl esters. These results indicate that under our experimental conditions, percolate recirculation had a positive effect on the OM degradation. Also OM stabilization is observed with relative increases in recalcitrant lignin at the expense of the more liable polysaccharide fraction. This paper represents the first attempt to apply Py-GC/MS to evaluate the OM quality in digestates obtained by SS-AD of pig slurry and straw optimized by percolate recirculation.
Comparison of thermochemolysis and classical chemical degradation and extraction methods for the analysis of carbohydrates, lignin and lipids in a peat bog J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-26 K. Younes, L. Grasset
Published data from different techniques used in the analysis of the main biomolecular families (lignin, carbohydrates and lipids) in 100 cm depth peat cores from the Sagnes peat bog (Limousin, France) were compared. Thermochemolysis using tetramethylammonium hydroxide was compared with the classical chemical degradation methods for lignin (CuO-NaOH oxidation) and carbohydrates (acid hydrolysis with HCl), and the Bligh and Dyer extraction method for lipids. Differences observed between the methods are mostly due to the different degradation mechanisms involved in each method. For lignin, the selective cleavage of β-O-4 aryl ether bonds during thermochemolysis allowed identification of a more oxidized/degraded lignin pool in the deepest part of the peat core. For carbohydrates, the capacity of thermochemolysis to detect free (or terminal) carbohydrates showed an increase in microbial contribution at the interfaces between three distinct peat layers: the acrotelm, the upper part of the peat permanently above the water table; the mesotelm, the layer where water table fluctuations occur; and the catotelm, the bottom layer of peat that is permanently below the water table. For the lipid fraction, thermochemolysis revealed a lipid pool that was more influenced by microbial reworking. These results imply that, depending on the techniques used, the interpretation of the extent of degradation or source could differ. Therefore, TMAH thermochemolysis could be viewed and used as a complementary method of analysis, offering additional molecular data and contributing to a better understanding of the nature and sedimentation processes of organic matter in peat bogs.
Experimental and DFT studies for the kinetics and mechanism of the pyrolysis of 2-(4-phenoxy-substituted)tetrahydro-2H-pyranes in the gas-phase J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-12 Alvaro Alvarez-Aular, Loriett Cartaya, Alexis Maldonado, Yeljair Monascal, David Santiago Coll, Gabriel Chuchani
The gas-phase pyrolysis kinetics of tetrahydropyranyl phenoxy ethers: 2-(4-cyanophenoxy)tetrahydro-2H-pyran, and 2-(4-bromophenoxy)tetrahydro-2H-pyran were studied in a static system, with allyl bromide as surface-effect deactivator, and in the presence of toluene to inhibit chain reactions. The temperature and pressure were 350–440 °C and 25–89 Torr, respectively. The pyrolysis is homogeneous, unimolecular, and consistent with the first-order rate law yielding 3,4-dihydro-2H-pyran (DHP) and the corresponding 4-substituted phenol. The Arrhenius equations were found as follows: 2-(4-cyanophenoxy)tetrahydro-2H-pyran log k1 (s−1) = (14.76 ± 0.12) − (232.1 ± 1.3) kJ mol−1 (2.303 RT)−1 2-(4-bromophenoxy)tetrahydro-2H-pyran log k1 (s−1) = (14.08 ± 0.15) − (209.1 ± 1.8) kJ mol−1 (2.303 RT)−1 DFT theoretical calculations were performed to 2-(4-substituted-phenoxy) tetrahydro-2H-pyranes with groups −H, −CH3, −C(CH3)3, −CN and Br. The calculated values for thermodynamic parameters using the WB97XD/6–311 + +G(d,p) level have a good agreement with the experimental values except for the cyano compound. Experimental and theoretical data suggest a mechanism with four-membered cyclic transition state (TS). The results indicate a small increment of rate constants values with raising electron donating ability groups in the phenoxy ring, and a slight decrease effect with electron withdrawing substituents. The effect of resonance structures giving by the phenyl ring seems to be the main factor in the TS stabilization. The assistance of the oxygen atom belonging to the phenoxy group in the pyranyl hydrogen abstraction exerts influence on the rate constants, but the polarization of Cδ+⋯δ−OPh bond is proposed as the rate determining process.
Microwave-assisted catalytic pyrolysis of Chinese Tallow kernel oil for aromatic production in a downdraft reactor J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-12 Zhenting Yu, Yunpu Wang, Lin Jiang, Leilei Dai, Yuhuan Liu, Roger Ruan, Dengle Duan, Yue Zhou, Liangliang Fan, Yunfeng Zhao, Rongge Zou
Microwave-assisted pyrolysis of Chinese tallow kernel oil with silicon carbide (SiC)-foamed ceramic catalyst in a downdraft reactor was carried out in this study. In this paper, we studied the influence of catalytic temperature, catalyst-to-feed ratio, and feeding rate on product distribution and chemical components of bio-oil. The aromatic proportion reached a maximum value of 89.707 wt% when catalytic conditions were set as follows: 300 °C catalytic temperature, 1:2 catalyst/feedstock ratio, and 1 ml/min feed rate. Fourier-transform infrared spectra were consistent with the results obtained from gas chromatography–mass spectrometry. Their outstanding thermal stability allowed SiC-foamed ceramics to perform well in five cycles of repeated experiments under optimal conditions. These results indicate that the SiC-foamed ceramics are promising catalysts for aromatic production in microwave-assisted pyrolysis of Chinese tallow kernel oil in a downdraft reactor. This pathway can also improve the application prospects of microwave pyrolysis technology.
Thermogravimetric analysis coupled with mass spectrometry of spent mushroom substrate and its fractions J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-12 Radoslaw Slezak, Liliana Krzystek, Stanislaw Ledakowicz
This study aimed at determination of the char, tar and gas production yield during pyrolysis of the spent mushroom substrate left after cultivation, as well as its individual components, namely the casing layer and the mushroom substrate. The pyrolysis process was carried out in a thermobalance combined with a mass spectrometer. Based on the analysis of mass losses, it was found that the largest amount of flammable gases and tar were released during pyrolysis of the spent mushroom substrate. The yield of char, tar and gas during pyrolysis at 600 °C were respectively equal to 57.1, 14.4 and 14.5 wt.%. The loss of mass at temperature above 600 °C was associated with thermal decomposition of calcium carbonate, calcium sulfate, and oxidation of the char. The deconvolution of DTG curves and volatile products such as H2, CH4, CO, CO2, H2O and tar allowed to determine the decomposition of the compounds contained in the spent mushroom substrate during the pyrolysis process. The kinetic parameters were calculated from the isoconversional model for thermal degradation of biomass. The results could aid in managing organic wastes including the energy production.
Characterization of fast pyrolysis bio-oil properties by near-infrared spectroscopic data J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-12 Torbjörn A. Lestander, Linda Sandström, Henrik Wiinikka, Olov G.W. Öhrman, Mikael Thyrel
Pyrolysis transforms bulky and heterogeneous lignocellulosic biomass into more easily-handled oils that can be upgraded into bio-based transportation fuels. Existing systems for monitoring pyrolysis processes and characterizing their products rely on slow and time-consuming wet chemical analyses. On-line near-infrared (NIR) spectroscopy could potentially replace such analyses, providing real-time data and reducing costs. To test the usefulness of NIR methods in characterizing pyrolysis oils and processes, biomass from conifers, Salix, and reed canary grass was milled and pyrolyzed at 675, 750, and 775 °C. Two separate pyrolytic fractions (aerosol and condensed) were produced in each experiment, and NIR spectra were collected for each fraction. Multivariate modelling of the resulting data clearly showed that the samples’ NIR spectra could be used to accurately predict important properties of the pyrolysis oils such as their energy values, main organic element (C, H and O) contents, and water content. The spectra also contained predictive information on the samples’ origins, fraction, and temperature treatment, demonstrating the potential of on-line NIR techniques for monitoring pyrolytic production processes and characterizing important properties of pyrolytic oils from lignocellulosic biomass.
Thermo-analytical study of 2,2,2-trinitroethyl-formate as a new oxidizer and its propellant based on a GAP matrix in comparison with ammonium dinitramide J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-11 Mohamed Abd-Elghany, Ahmed Elbeih, Thomas M. Klapötke
A new high energy dense oxidizer (HEDO) 2,2,2-trinitroethyl-formate (TNEF) was prepared and characterized by nuclear magnetic resonance (NMR). A new propellant based on glycidyl azide polymer (GAP) and TNEF was prepared. Thermo-analytical study of TNEF in comparison with ammonium dinitramide (ADN) and their propellant formulations based on GAP were investigated. The decomposition gaseous products and the combustion characteristics of the propellants were determined by using thermodynamic code (EXPLO5_V6.03). Scanning electron microscope (SEM) technique was applied to clarify the crystal morphology of the oxidizers in addition to the homogeneity of the propellants ingredients. Impact and friction sensitivities of the oxidizers and the GAP binder were measured. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques were used to study the pyrolysis of the oxidizers as well as the prepared propellants. The decomposition kinetics were determined by Kissinger and Kissinger–Akahira–Sunose (KAS) methods The thermal degradation of ADN is faster than TNEF oxidizer. ADN and TNEF have melting temperatures at 95.5 and 127.1 °C and maximum decomposition temperature at 183.5 and 210.1 °C respectively. In addition, TNEF has activation energy in the range of 131–146 kJ mol−1, while ADN has activation energy in the range of 114–117 kJ mol−1. TNEF has specific impulse (250.1 s) higher than ADN (202.4 s). TNEF is a promising oxidizer to be used in composite solid rocket propellants.
Valorizing Municipal Solid Waste: Waste to Energy and Activated Carbons for Water Treatment via Pyrolysis J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-03 Chitanya Gopu, Lihui Gao, Maurizio Volpe, Luca Fiori, Jillian L. Goldfarb
Globally, as societies urbanize and demand for energy increases, the need to manage mounting quantities of municipal solid waste (MSW), produce renewable energy, and insure clean water supplies becomes more pressing each year. These issues could be addressed by integrating pyrolysis of MSW to recover liquid and gaseous biofuels and a solid biochar, with CO2 activation of the latter to produce activated biochars for water treatment. This potential conversion pathway is experimentally demonstrated by pyrolyzing a model MSW stream at 408 °C, the peak mass loss rate pyrolysis temperature and compared to pyrolysis at 900 °C. As pyrolysis temperature increases, we see conversion of plastic intermediaries into paraffins and polycyclic aromatic compounds, though the desirable gas components (methane, hydrogen, carbon monoxide) of the pyrolysis gas increase substantially. The CO2 activated biochars (activated at 600 °C and 900 °C) show surface areas over 300 m2/g, with the lower pyrolysis temperature and higher activation temperature yielding the highest areas. Adsorption experiments were performed with methylene blue to determine the ability of the activated MSW-biochar to remove organic pollutants from water. Adsorption is well described by the Langmuir isotherm, with equilibrium adsorption capacities upwards of 250 mgdye/g for all activated biochars.
Analytical pyrolysis to gain insights into the protein structure. The case of ovalbumin J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-01 Sibilla Orsini, Emilia Bramanti, Ilaria Bonaduce
We report a novel study based on analytical pyrolysis coupled with mass spectrometry to investigate, at the molecular level, the formation of aggregates and cross-linked structures in ovalbumin (OVA). For this scope, OVA was dissolved in water at different concentrations and temperatures (up to 80 °C), and was added with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC). The formation of β-sheets and intermolecular aggregates, which are stabilized by weak hydrophobic and hydrogen bonds, is favoured in OVA by higher protein concentration and temperatures. The cross-linker (EDC) gives the formation of covalent bonds randomly distributed in the protein, inducing significant portions of random coil structures in OVA. FTIR-ATR spectroscopy was employed to study the protein conformation. Evolved gas analysis coupled with mass spectrometry (EGA-MS) and pyrolysis coupled with gas chromatography mass spectrometry (Py-GC-MS) were used to characterise the gaseous compounds evolved during pyrolysis at the different temperatures. Aggregation and cross-linking increase the thermal stability of OVA and significantly affect its pyrolytic profile. The study reveals that analytical pyrolysis coupled to mass spectrometry can be used to gain insights into the protein structure.
The Effect of Temperature, Heating Rate, Initial Cross-linking and Zeolitic Catalysts as Key Process and structural Parameters on the Degradation of Natural Rubber (NR) to Produce the Valuable Hydrocarbons J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-05-01 Zaher Tamri, Ali Vaziri Yazdi, Mehdi Nekoomanesh Haghighi, Mehrdad Seifali Abbas-Abadi, Amir Heidarinasab
In this study, the effects of different zeolite based catalysts, initial crosslinking, temperature and heating rate as key process and structural parameters on the thermal degradation of natural rubber (NR) were investigated. The product composition containing liquid, gas and coke yield as well as the varied components of liquid product as a function of the studied parameters in the stirred reactor were compared. The degradation temperature, heating rate, initial crosslinking and catalyst type affected on the formation of aromatic and aliphatic products appreciably. The results showed that the thermal pyrolysis of natural rubber tended to follow the un-zipping and Diels-Alder mechanisms significantly though the catalytic pyrolysis reduced the unzipping share and enhanced the Diels-Alder reactions. Meanwhile, the results showed that the non-vulcanized sample produced the maximum condensed hydrocarbons at 450 °C and the medium heating rate in the studied range. The studied degradation mechanism using TGA instrument indicated that the ratio of crosslinking over chain scission and unzipping decreased with increase in temperature and heating rate. Generally, it showed that the double bond in the polymer structure beside the heating rate could played an important role in the degradation mechanism and the products. The results indicated that activation energy decreased with increasing the heating rate (171.06–136.51 kJ mol−1).
Microwave-assisted catalytic co-pyrolysis of soybean straw and soapstock for bio-oil production using SiC ceramic foam catalyst J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-27 Yunpu Wang, Lin Jiang, Leilei Dai, Zhenting Yu, Yuhuan Liu, Roger Ruan, Guiming Fu, Yue Zhou, Liangliang Fan, Dengle Duan, Yunfeng Zhao
Microwave-assisted catalytic co-pyrolysis of soybean straw and soapstock was investigated by using silicon carbide ceramic foam as catalyst. The study determined the effects of catalytic temperature, feed-to-catalyst ratio, and soybean straw-to-soapstock ratio on product yield and chemical composition. Experimental results indicated high yield and ratio of hydrocarbon in bio-oil were observed at a catalytic temperature of 350 °C. The use of a catalyst enhanced the hydrocarbon proportion at the expense of decreased in bio-oil yield. A significant synergistic effect was observed during co-pyrolysis of soybean straw and soapstock, and this effect facilitated hydrocarbon production from bio-oil.
Effect of thermal pretreatment on the extraction of potassium salt from alga Saccharina japonica J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-27 Patrick Boakye, Divine D. Sewu, Seung H. Woo
Interests in conversion of macroalgae to bioenergy via thermal treatment, namely pyrolysis or combustion has increased due to their distinctive composition and high photosynthetic rates. The resulting char byproducts could serve as a trove of precious mineral resources. Thermal pretreatment was compared with direct extraction of potassium salts from alga Saccharina japonica using deionized water for use as food additive, agricultural or pharmaceutical applications. Biomass was pyrolysed with fixed bed reactor or combusted with muffle furnace at 300, 450, 600 °C, and extracted using deionized water in shaker at 150 rpm and 30 °C for 2 h. Overall potassium salts recovery efficiency from raw biomass (52.55 ± 2.79%) was relatively lower than from 450 °C chars from pyrolysis (75.30 ± 0.81%) and combustion (62.07 ± 0.56%). Extracts from pyrolysed char at 600 °C had highest purity of KCl which is most abundant mineral in all products. SEM-EDX and ICP-OES elemental analysis confirmed absence of heavy metals such as As, Cu, Cd and Pb in extracts. Ratios of organic to inorganic fractions in extracts from thermally pretreated samples were much lower (∼ 0.1) than that of raw biomass (8.42).
Proximate Analysis of Coal by Micro-TG method J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-25 Krzysztof M. Czajka
The presented paper examines the feasibility of the application of micro-TG for the sake of proximate analysis of coal. It is aimed to develop a reliable and versatile procedure which allows to determine the content of each coal constituent during one experimental run. Among several investigated factors (i.e. temperature, heating rate, residence time, etc.), a special focus is given to the procedure of purging the TG furnace, which is claimed to be a possible source of erroneous moisture content determination. Analysis performed for nine samples indicates that the proposed method provides results close to these given by standardized approach, while discrepancies in the amount of measured moisture, volatile matter, fixed carbon and ash are not higher than 0.2%, 0.6%, 1.0% and 1.0% respectively.
Catalytic fast pyrolysis of rice husk: effect of coupling leaching with torrefaction pretreatment J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-25 Shuping Zhang, Shuguang Zhu, Houlei Zhang, Tao Chen, Yuanquan Xiong
The effect of coupling leaching with torrefaction pretreatment process on bio-oil production from catalytic fast pyrolysis using ZSM-5 zeolite catalyst was evaluated by Py-GC/MS. During coupling leaching with torrefaction pretreatment, the fuel characteristics and structural characteristics of rice husk samples were changed, which were evaluated using proximate, ultimate, and calorific analyses, Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD) techniques. The experimental results of catalytic fast pyrolysis indicated that coupling leaching with torrefaction pretreatment further improved the relative contents of BTX (benzene, toluene and xylene) compounds in bio-oil compared to that of raw rice husk sample. It was mainly ascribed to the effective removal of metallic species during leaching process. In addition, the selective removal of hemicellulose fraction and the increasing lignin fraction and changes in the structure of lignin (cleavage of ether linkages and demethoxylation) during torrefaction process also plays positive roles. Severe torrefaction process resulted in the cross-linking and charring of sample, thus reducing the formation of BTX compounds. Thus, coupling leaching with middle torrefaction pretreatment process was the optimum pretreatment conditions for catalytic fast pyrolysis of rice husk samples.
Formation of synthetic sludge as a representative tool for thermochemical conversion modelling and performance analysis of sewage sludge – Based on a TG-FTIR study J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-24 Wei Ping Chan, Wang Jing-Yuan
Feasibility of thermochemical conversion processes to convert sewage sludge into valuable products such as pyrolytic oil, synthetic gases and biochar is attracting great research interests. However, uncertainty in kinetics analysis and conversion modelling of sludge is considered as a significant barrier for accurate determination and understanding of its conversion pathways, kinetic parameters, and process optimisation. This is caused by the heterogeneity and complexity in composition of sludge since multiple thermal degradation reactions of different components occurred concurrently. Therefore synthetic sludge study is carried out to establish a component-based methodology to produce a representative tool for sludge conversion modelling and to address these issues. Synthetic sludge is formed based on an analytical survey on sludge samples collected from Water Reclamation Plants (WRPs) in Singapore and selective screening of model compounds. Dried sludge (CsY) collected from Changi Water Reclamation Plant (WRP) is used as a reference waste sample in this study. Thermochemical properties, multiple heating rates thermogravimetric analysis (TG-DTG), kinetics study, products evolution analysis, Fourier-Transform Infrared Spectroscopy (FTIR) spectra obtained from synthetic sludge and collected real sludge samples were analysed and compared. Acceptable representation with improved consistency was achieved with discrepancy identified for further improvement on composition analysis and model compounds selection. With this modifiable tool, synthetic sludge of controllable composition could then be applied in complex thermochemical process analysis as a representative compound to improve consistency of the results. Composition of sludge could also be manipulated as a control parameter to develop study on impacts of feedstock properties to the performance and optimisation of thermochemical conversion processes.
Bio-oil production via catalytic microwave co-pyrolysis of lignin and low density polyethylene using zinc modified lignin-based char as a catalyst J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-22 Hervan Marion Morgan Jr., Jianghui Liang, Kun Chen, Lishi Yan, Kui Wang, Hanping Mao, Quan Bu
In order to improve the product quality and make the process more sustainable, lignin-based char was used as a catalyst during microwave co-pyrolysis of lignin and low density polyethylene (LDPE). Lignin-based char modification using zinc transition metal proved to be beneficial by improving the porosity and selectiveness of the prepared catalyst. General selectivity of lignin-based char catalyst was observed to produce bio-oil with high selectivity of valued compounds. GC/MS analysis proved that the major chemical components of the bio-oil were hydrocarbons, ketones, alcohols, phenols and guaiacols(∼70%). A central composite experimental design (CCD) was used to optimize the product yield and component composition. The optimum condition to produce the highest quantity and quality of bio-oil was 450 °C and 12.5% LDPE/lignin ratio. GC analysis of the syn-gas revealed that the valued compounds were H2, CO and CH4, the content of which was about 40%, 20% and 5%, respectively.
Nitrogen retention of biochar derived from different feedstocks at variable pyrolysis temperatures J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-21 Simeng Li, Vanessa Barreto, Runwei Li, Gang Chen, Yuch P. Hsieh
Pyrolysis temperature is known to affect the potential of biochar as a nutrient-holding soil amendment, but the mechanism is unclear. In this study, physiochemical properties of biochar derived from switchgrass, water oak and biosolid at different pyrolysis temperatures were characterized using multiple techniques. In addition, biochar sorption of nitrogen nutrients in forms of ammonium (NH4+), nitrite (NO2−) and nitrate (NO3−) was investigated. The results indicated that the profound effects of pyrolysis temperature on biochar physiochemical properties were feedstock-specific. Similarly, biochar derived from different feedstocks at different temperatures exhibited different strengths to retain NH4+, NO2− and NO3−. The maximum NH4+ retention capacities were found with the biochar of switchgrass produced at 800 °C (10.47 mg g−1), biochar of water oak at 400 °C (3.82 mg g−1), and raw biosolids (43.29 mg g−1). Meanwhile, biochar was found to have limited (switchgrass and water oak) and negative (biosolids) retention for NO2− and NO3−. The cation exchange capacity (CEC) and morphological characteristics (e.g., porosity) were found to be the predominant factors affecting biochar NH4+ sorption.
Effects of extractable compounds on the structure and pyrolysis behaviours of two Xinjiang coal J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-21 Ping Zhu, Anqi Luo, Feng Zhang, Zhiping Lei, Jinli Zhang, Jianshu Zhang
The extractable compounds are a very important part of coal and play an important role in the pyrolysis of coal. To further understand the effect of the extracts on the structure and pyrolysis behaviours of coal, Naomaohu (NMH) lignite and Hutubi (HTB) bituminous coal were extracted with pyridine and swollen with its solvent vapor. The pyrolysis process was performed in a fixed-bed reactor. Thermogravimetric analysis (TGA) of the coal samples was carried out on a thermogravimetric (TG) analyser. The pore structure characteristics of the coal samples and their chars obtained from pyrolysis at different temperatures were measured by the mercury intrusion porosimetry (MIP) method. The components of the pyrolysis gas were detected by gas chromatography (GC). It was found that the extraction and swelling processes enlarged the pore size and improved the porosity of the coals to some extent. Compared with the pyrolysis of the raw coal, that of the swollen coal resulted in a higher tar yield owing to the destruction of the cross-linked structure and the variations in the coal structure; the tar yield for the pyrolysis of all the residues decreased significantly, but the gas yield increased, where the volume of the CO gas mainly increased. The NMH residue char obtained from pyrolysis of the residue at different temperatures had a lower proportion of micropores than the HTB residue char. The extractable compounds will be converted to gas-phase (e.g. volatiles) and liquid-phase (e.g. colloids) products during the pyrolysis process, which could stabilise the free radical fragments, form coke in the pore structure of the char and increase the number of new micropores formed.
Plasma upgrading of guaiacol as lignin pyrolytic-oil model compound through a combination of hydrogen production and hydrodeoxygenation reaction J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-20 Hamed Taghvaei, Mohammad Reza Rahimpour
In this study, hydrodeoxygenation reaction is conducted without using hydrogen as a feed. The required hydrogen was provided in situ through plasma decomposition of methoxyl and methyl radicals which exist in the chemical structure of lignin pyrolytic-oil at room temperature. Operating parameters including applied voltage, Ar flow rate and discharge length were carefully studied in order to maximize the conversion and degree of deoxygenation. A guaiacol conversion of 81% and deoxygenation degree of 52% were achieved at an applied voltage of 12 kV and a discharge length of 20 cm without using any catalyst and hydrogen. By optimizing discharge length and Ar flow rate, conversion increase by 36% and power consumption reduced by 33%. Unlike previous studies in which catechol was produced as a major product, in this study phenol is produced selectively through direct demethoxylation rather than demethylation reaction. Due to operation at low temperature and atmospheric pressure no hydrogenation of aromatic ring was observed. Results show that the non-thermal plasma is capable for the upgrading of guaiacol and may pave the way towards the hydrogen-free hydrodeoxygenation reaction.
Catalytic fast co-pyrolysis of biomass and fusel alcohol to enhance aromatic hydrocarbon production over ZSM-5 catalyst in a fluidized bed reactor J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-20 Bo Zhang, Zhaoping Zhong, Jing Zhang, Roger Ruan
In order to enhance aromatic hydrocarbon production, catalytic fast co-pyrolysis (co-CFP) of corn stover and fusel alcohol is conducted with ZSM-5 catalyst in a fluidized bed reactor. Effects of co-CFP temperature, catalyst loading and mass ratio of fusel alcohol to biomass on aromatic hydrocarbon yields are investigated and the experimental results show that bio-derived aromatic hydrocarbons can be formed through Diels-Alder cycloaddition and catalyst-induced hydrocarbon pool. It is found that co-CFP temperature of 550 °C results in the maximum aromatic hydrocarbon yield and the carbon and hydrogen yields of individual and total aromatic hydrocarbons increase dramatically with an elevated catalyst loading amount. Additionally, an apparent synergy between biomass and fusel alcohol is observed during co-CFP. With the consideration of aromatic hydrocarbon yields in bio-oil, the mass ratio of fusel alcohol to biomass of 1:1 in the blends is the best option. Moreover, isotopic labeling technique is utilized to unearth the origin of carbon and hydrogen in aromatic hydrocarbons, and the results demonstrate that carbon and hydrogen atoms from both feedstocks can coexist in the individual aromatic hydrocarbon and make up the targeted products during co-CFP of the blends.
Atmospheric hydrodeoxygenation of bio-oil oxygenated model compounds: A review J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-20 Hamed Pourzolfaghar, Faisal Abnisa, Wan Mohd Ashri Wan Daud, Mohamed Kheireddine Aroua
Hydrodeoxygenation (HDO) of various bio oil oxygenated model compounds in low H2 pressure has been discussed in this study. Because of the high yield of aromatic mixtures in bio-oil, they carry great potential for fuel efficiency. Nevertheless, due to its high viscosity, abundance of acid, and heteroatom contaminants, the bio-oil ought to be upgraded and hydrotreated in order to be applied as an alternative fuel. A continuous low H2 pressure HDO of bio-oil is favored as it could be simply integrated with conventional pyrolysis systems, functioning at low pressures, as well as supporting a flexible plan for serial processing in respective bio-refineries. Additionally, such a process is cheaper and safer in comparison with the high pressure set ups. This review meticulously elaborates on the operation conditions, challenges, and opportunities for using this process in an industrial scale. The operating temperature, the H2 flow ratio, the active site, and the catalyst stability are some important factors to be considered when it is intended to reach a high conversion efficiency for the HDO in low H2 pressure.
Association of chemical structure and thermal degradation of lignins from crop straw and softwood J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-13 Yanqin Huang, Huacai Liu, Hongyou Yuan, Xiuzheng Zhuang, Song Yuan, Xiuli Yin, Chuangzhi Wu
The structural characteristics of crop straw (wheat straw, WS) lignin and softwood (pine wood, PW) lignin prepared using the enzymatic/mild acid hydrolysis method (EMAL) were deeply elucidated by FTIR (Fourier transform infrared), 13C-1H 2D-NMR (nuclear magnetic resonance), and quantitative 31P-NMR combined with DFRC (derivatization followed by reductive cleavage). Then, the association of chemical structure and thermal degradation was evaluated by means of TG-FTIR-MS (thermo-gravimetric-FTIR-mass spectrometry) and Py-GC/MS (pyrolysis-gas chromatography/mass spectrometry). The results showed that the functional groups and aromatic unit compositions of WS-EMAL were distinct from those of PW-EMAL, identifying the former as a HGS-lignin and the latter as a typical G-lignin. Both WS-EMAL and PW-EMAL were mainly cross-linked by β-O-4 linkages but had different contents. The amount of uncondensed β-O-4 linkages in WS-EMAL was 1168 μmol/g, which was lower than that in PW-EMAL (1297 μmol/g). These distinctions in structure caused a large difference in thermal stability, evolution behavior of typical volatiles and selectivities of G-, S-, H-, C-phenols between the two lignins. The mechanistic influence of structural features on pyrolysis behavior was intensively discussed, and a correlation between the two lignins was obtained.
Application of TG-FTIR analysis to superfine pulverized coal J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-12 Jun Shen, Jiaxun Liu, Yanfeng Xing, Hai Zhang, Lei Luo, Xiumin Jiang
Thermogravimetric test combined with FTIR analysis is conducted to reveal the yield profile of gaseous species and functional groups, both for conventional and superfine pulverized coal (average particle size below or around 20 μm). Generally speaking, the yield of CO2 is less for superfine pulverized coal particle compared with conventional particle size. Since the content of carbonyl group is reduced, the amount of CO2 released during the pyrolysis is more for coal of lower rank (i.e. Neimenggu bituminous coal). CO yield of Neimenggu coal is greater than Shenhua coal, because more side chains and hydroxyl groups are owned by coal of lower rank (i.e. Neimenggu bituminous coal). As CO group is likely to be linked to the same compound as CC group, the profile of CO group is similar to CC group. H2O evolution of superfine pulverized coal is higher than conventional particle size, for the impact of mechanochemical force for finer particle may be more prominent. With the decrease of the coal particle size, yield trend of CH4 gradually decreases, indicating that superfine pulverized coal is possibly engaged in NO reduction at the early stage of pyrolysis.
Distribution of PCDD/Fs over the three product phases in wet sewage sludge pyrolysis J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-10 Qianjin Dai, Junming Wen, Xuguang Jiang, Liyan Dai, Yuqi Jin, Fei Wang, Yong Chi, Jianhua Yan
Pyrolysis of wet sewage sludge was conducted using (1) conventional pyrolysis (CP) by electric heating and (2) microwave pyrolysis (MP) by microwave heating separately to obtain the emission characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during pyrolysis. Tests were conducted in parallel on two set-ups. The 4 to 8-chlorinated PCDD/Fs were determined by gas chromatography/mass spectroscopy (GC/MS) in each of the resulting product phases (gas, liquid and solid phase). During the evolution of PCDD/Fs mainly migration rather than formation of congeners was observed, while liquid phase were dominant for PCDD/Fs amount. Effects of distillation and dechlorination appeared in the yield of gas and liquid phase. Totally chlorinated congeners such as OCDD and OCDF were mostly dechlorinated to lower chlorinated congeners. PCDD/Fs in gas phase and liquid phase increased along with power increase for MP and peaked before 700 °C for CP, while the amount differed little for solid phase. It was indicated from CP that PCDD/Fs were decomposed at 800 °C for wet sewage sludge pyrolysis. PCDD/Fs distribution in the three resulting product phases can be well explained by the boiling point, wherein OCDF was always relatively more difficult to be distillated than other congeners. MP produced equivalent quantity of PCDD/Fs compared with CP, which indicated the absence of special effect (nonthermal effect) of microwave heating on PCDD/Fs evolution.
Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-09 Tong Han, Nanta Sophonrat, Panagiotis Evangelopoulos, Henry Persson, Weihong Yang, Pär Jönsson
Study of the thermal behavior, kinetics, and product characterization of biomass and low-density polyethylene co-pyrolysis by thermogravimetric analysis and pyrolysis-GC/MS J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-07 Yunwu Zheng, Lei Tao, Xiaoqing Yang, Yuanbo Huang, Can Liu, Zhifeng Zheng
The present study aims to improve the yields and selectivity of aromatic hydrocarbons in the catalytic pyrolysis of biomass by the addition of low-density polyethylene (LDPE), which has a higher hydrogen-carbon ratio than biomass. We have investigated the thermal decomposition behavior and kinetics, as well as the product distribution, of the co-pyrolysis of biomass (cellulose and pine sawdust) and plastic (LDPE) both with and without a catalyst (HZSM-5) using thermogravimetric analysis (TGA) and analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Our results, based on the weight loss difference (△W), show that there is a positive and synergistic interaction between the biomass and LDPE. After the addition of LDPE, the synergistic reactions inhibited catalyst coking effectively and decreased the formation of solid residues. In addition, the ZSM-5 catalyst improved the reaction activity and reduced the activation energy, although the reaction mechanism is not changed. At the same time, the Flynn-Wall-Ozawa (FWO) method was used to fit the kinetic data for both non-catalytic and catalytic co-pyrolysis of biomass and LDPE, and the activation energies (Ea) of the cellulose + LDPE + catalyst and pine + LDPE + catalyst systems were found to be 168.81 and 185.87 kJ/mol, respectively. The co-pyrolysis of biomass and LDPE effectively improved the yield and selectivity of aromatics and increased the selectivity for benzene, toluene, xylene, and ethylbenzene (BTXE). The addition of LDPE can effectively improve the selectivity for naphthalene family products (methylnaphthalene and 2-methylnaphthalene) in the catalytic pyrolysis of biomass and decrease the content of aromatic hydrocarbons larger than C10.
Structural transformations of wood and cereal biomass components induced by microwave assisted torrefaction with emphasis on extractable value chemicals obtaining J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-07 Maris Lauberts, Liga Lauberte, Alexandr Arshanitsa, Tatiana Dizhbite, Galina Dobele, Oskars Bikovens, Galina Telysheva
A comparative study of the modification of chemical structure of wheat straw and aspen wood initiated by microwave (MW) assisted torrefaction at different temperatures (150 − 300 °C) was carried out using Py-GC/MS-FID, FTIR, GC-FID and wet chemistry procedures as the main analytical tools. Differences in wood and wheat straw thermal transformations in the course of MW assisted torrefaction were revealed. Formation of extractable chemicals as the result of biomasses torrefaction was established. The most significant increase in formation of hydrophilic extractable chemicals was found for the both biomasses after torrefaction in the range of 250 − 280 °C. Antioxidant activity of extracts was assessed by the test with a free radical DPPH . The UPLC-ESI-MS/MS analysis of extracts from the both torrefied biomasses showed the presence of lignin-carbohydrate complex fragments. It was detected that a flavonoid monomer tricin and its derivatives were the dominant compounds in hydrophilic extracts from wheat straw. The results of the study provide useful information for valorization of potentially valuable lignocellulosic destruction products, which can be extracted from torrefied wood and cereal biomass.
Comparison of the thermal degradation behaviors and kinetics of palm oil waste under nitrogen and air atmosphere in TGA-FTIR with a complementary use of model-free and model-fitting approaches J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-05 Zhongqing Ma, Junhao Wang, Youyou Yang, Yu Zhang, Chao Zhao, Youming Yu, Shurong Wang
Palm oil waste from palm oil industry is a promising biomass resource for bio-fuels and bio-chemicals production by biomass thermochemical conversion technology. In this paper, thermogravimetric analyzer coupled with fourier transform infrared spectrometry (TGA-FTIR) were used to investigate the difference of the thermal degradation behaviors and kinetics of palm kernel shell under nitrogen and air atmosphere. Based on the TG analysis, the weight loss in the third stage with the air atmosphere was higher than the nitrogen atmosphere, presenting as weight loss of 12.4 wt.% in the carbonization stage of nitrogen atmosphere and 36.9 wt.% in combustion stage of air atmosphere. Based on the 3D-FTIR analysis, the dominant components in the nitrogen atmosphere was CO2, C O bond contained organics, and C H or C O bond contained organics, while CO2 and H2O in the air atmosphere. The evolution and formation mechanism of non-condensable inorganic gaseous components (H2O, CH4, CO2 and CO) in the two atmospheres were remarkably different. The H2O and CO2 were mainly contributed by the breakage of OH group and the cracking/reforming reaction of C O and COOH groups in the nitrogen, however higher contents of H2O and CO2 were observed because of the combustion reaction in the air. The CH4 and CO were mainly contributed by the decomposition of OCH3, CH3, CH2 groups and the cracking of carboxyl group in the nitrogen, while the content of CH4 decreased by the diluting of H2O and CO2, and the CO increased by the incomplete combustion reaction in the air. The kinetic triple (mechanism function, activation energy, and pre-exponential factor) was estimated by the combined use of model-free (Ozawa and Kissinger) and model-fitting (Šatava-Šesták) method.
Ni-doped high silica HZSM-5 zeolite (Si/Al = 200) nanocatalyst for the selective production of olefins from methanol J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-05 Mohammad Rostamizadeh, Fereydoon Yaripour, Hossein Hazrati
This study deals with the modification of high silica H-ZSM-5 zeolite by different transition metals (nickel, iridium and silver). The nanocatalysts were characterized by XRD, FE-SEM, FT-IR, NH3-TPD, Pyridine adsorption IR spectra (Py-IR) and N2 adsorption-desorption. The metal (0.5 wt.%) was introduced by wet impregnation technique including multi-steps. The promoter species were uniformly distributed on the nanocatalyst without significant damage of the structure. The nickel impregnation resulted in the high crystallinity (97.2%) and well-adjusted acidity (strong/weak acidity = 0.98). The results showed that the nickel impregnation not only modulated the concentration of acid sites but also regulated the acid type. The highest methanol conversion (99.9%), light olefins selectivity (84%) and the lowest C5+ selectivity (<10%) showed the high efficient performance of the nickel-doped ZSM-5 nanocatalyst in methanol to olefin (MTO) reaction for long time on stream.
Coupling pyrolysis with mid-infrared spectroscopy (Py-MIRS) to fingerprint soil organic matter bulk chemistry J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-04-04 Nkwain Y. Funkuin, Michael S. Demyan, Frank Rasche, Marie-France Dignac, Elke Schulz, Thomas Kätterer, Torsten Müller, Georg Cadisch
A novel method coupling pyrolysis with mid-infrared spectroscopy (Py-MIRS) was developed to characterize soil organic matter (SOM) chemistry in soils. The pyrolyzer was interfaced to the MIR spectrometer by means of a Brill cell™ (CDS Analytica). The set-up generates pyrolysis fingerprint spectra from which individual pyrolysis products can be related to SOM bulk chemistry. Py-MIRS development involved the testing of experimental conditions like pyrolysis temperature (550, 700, 1000 °C), heating rate (20 °C s−1 and 20 °C ms−1) and time (15, 30 and 60 s) using reference standard compounds ranging from carbohydrates to phenols varying in chemical and structural composition like levoglusogan, gluten, tannin, syringol, pectin and leucine falling within different compound categories (carbohydrates, amino acids, proteins, phenols, etc) as well as soil samples. Pyrolysis yields of prominent specific functional groups, like aliphatics (C-H stretching at 2930 cm−1) and C C aromatics (1510 cm−1), varied with pyrolysis temperature, heating rate and time. The preferred settings for high pyrolysis yield and minimized secondary reactions were obtained at a pyrolysis temperature of 700 °C, heating rate of 20 °C ms−1 and heating time of 30 s. The suitability of Py-MIRS to detect changes in SOM composition was evaluated by comparing Py-MIRS results to Diffuse Reflectance Fourier Transform mid-Infrared Spectroscopy (DRIFTS) results. Soil samples taken from the Static Fertilization Experiment, Bad Lauchstädt, Germany (Chernozem) revealed a major SOM contribution of the peak at 1750 cm−1 (C O), followed by peaks at 950 (C-H), 1510 (C C), 1176 (C-H, O-H) cm−1, with smaller contributions from the 2930 (C-H) and 3015 (CH4) cm−1 peaks, apart from a dominant CO2 peak. Using the preferred pyrolysis settings, Py-MIRS as well as DRIFTS results further indicated that soils receiving organic (e.g. farmyard manure) inputs were highly enriched in aliphatic groups, while their absence favored the accumulation of carboxyl and aromatic groups as well as polysaccharides. Py-MIRS allowed via semi-quantification of pyrolysis products a rapid monitoring of SOM bulk chemistry with a high degree of reproducibility. It was concluded that Py-MIRS represents a fast, effective and reproducible technique to characterize changes in the SOM bulk chemistry as a result of management practices. It also allows to minimize acknowledged constraints of other analytical techniques used to characterize SOM bulk chemistry such as mineral interferences and associated secondary reactions.
Forensic comparison of pyrograms using score-based likelihood ratios J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-31 Agnieszka Martyna, Grzegorz Zadora, Daniel Ramos
The comparative analysis of chromatographic profiles of materials is the subject of interest in many scientific fields, including forensic science. Plastic microtraces collected during hit-and-run accidents and examined with pyrolysis gas chromatography mass spectrometry (Py-GC-MS), may serve as an example. The aim of comparing the recovered and control samples is to help reconstruct the event by commenting on their common, or not, sources. The objective is to report the evidential value of data in the context of two competing hypotheses: H1-both samples share common origins (e.g. car) and H2-they do not share common origins. The likelihood ratio approach (LR) addresses this idea as an acknowledged method within the forensic community. However, conventional feature-based LR models (using e.g. signal intensities of the chromatographically separated compounds) suffer from the curse of multidimensionality. Their considerable complexity can be reduced in the score-based LR models. In this concept the evidence expressed by the score, computed as a distance between the recovered and control samples characteristics, is evaluated using LR. A score solely based on a distance or a measure of similarity, without taking into account typicality, may not reflect the differences between similar samples clearly in a highly multidimensional space. Here we show that boosting the between-samples variance (B) whilst minimising the within-samples variance (W) helps distinguish between samples and improves the score-based LR models performance. Instead of computing the distances in the feature space, the authors use the space defined by ANOVA simultaneous component analysis, regularised MANOVA and ANOVA target projection that find directions with the magnified differences between B and W. The concept was successfully illustrated for 22 plastic containers and automotive samples, examined using Py-GC-MS. The research shows that this so-called hybrid approach combining chemometric tools and score-based LR framework yields a performing solution for the comparison problem for Py-GC-MS chromatograms.
Thermogravimetry and evolved gas analysis for the investigation of ligand-exchange reaction in thiol-functionalized gold nanoparticles J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-30 Federico Locardi, Ester Canepa, Silvia Villa, Ilaria Nelli, Chiara Lambruschini, Maurizio Ferretti, Fabio Canepa
Mechanism of Thermal Degradation of Aryl Bisphosphates and the Formation of Polyphosphates J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-29 Chuanchuan Liu, Qiang Yao
Thermal decomposition of yttrium propionate: Film and powder J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-27 Silvia Rasi, Susagna Ricart, Xavier Obradors, Teresa Puig, Pere Roura, Jordi Farjas
The processes involved in the thermal decomposition of yttrium propionate in oxidizing and inert atmosphere were analyzed with thermoanalytical techniques (thermogravimetry and evolved gas analysis) and with the help of structural characterization (X-ray, diffraction, infrared spectroscopy and elemental analysis) of intermediate and final products. Samples in the form of films and powders were analyzed. The decomposition behavior studied as a function of the particles’ size and the film thickness was investigated. We conclude that, as a consequence of the gas and heat transport, films decompose differently than powders. Finally, two decomposition mechanisms are proposed that are in agreement with the observed volatiles and intermediate phases.
A Novel Solar Powered Biomass Pyrolysis Reactor for Producing Fuels and Chemicals J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-26 Asif H. Rony, Daniel Mosiman, Zhao Sun, Dengfeng Qin, Yuan Zheng, John H. Boman IV, Maohong Fan
Thermo-Catalytic Reforming of Co-form® Rejects (Waste Cleansing Wipes) J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-22 Miloud Ouadi, Charles Greenhalf, Nils Jaeger, Lais Galileu Speranza, Andreas Hornung
Co-form® products are typically used for personal hygiene care (cleansing wipes), household cleaning (pads and mops) and absorbent applications. Co-form® is a thermo-bonded multilayer nonwoven composite and Kimberly-Clark patented its process in 2008. Co-form® rejects are composed of 30% plastic polypropylene and 70% wood pulp fibre. It is difficult to recycle and to-date no research articles explore pyrolytic valorisation for its energy recovery. This paper investigated pyrolytic valorisation of co-form® rejects into energy vectors. Pelletised co-form® rejects obtained from a secondary fibre paper mill were processed using a laboratory scale 2 kg/h Thermo-Catalytic Reforming (TCR®) reactor. The TCR® process combines intermediate pyrolysis, using an auger reactor to heat the material under moderate temperatures (350–450 °C) and moderate solid residence times (minutes) in the complete absence of Oxygen, with post catalytic reforming in a fixed bed reactor at 700 °C. Pelletised co-form® rejects were successfully converted into 12 wt% bio-oil, 9 wt% aqueous phase liquid, 8 wt% char and 71 wt% syngas products. The bio-oil higher heating value was found to be 39.36 MJ/kg, comparable to biodiesel. Naphthalene was found to be the most abundant aromatic compound within the oil, with a relative abundance of 15.22% measured by GC-MS. Oleic acid methyl ester (15.86%) was the most abundant long chain hydrocarbon detected. The higher heating value of produced gas was 11.02 MJ.Nm3 and char 30.79 MJ/kg. TCR® conversion of co-form® rejects proved to be a feasible route for the valorisation of this waste stream into sustainable energy vectors. In previous works, gasification processes could not successfully convert organic waste streams with a high plastic content, without implications attributed to agglomeration and melting of plastics. The TCR® process overcome these issues with no evidence of agglomeration or melting of plastics present within the reactor. The success was believed to be through applying moderate heating rates (°C/min) and temperatures (max 700 °C), as well as the mechanical effect of continuous mixing of material within the reactor via the internal auger screw. Overall, TCR® is a promising future route for the valorisation of co-form® rejects to produce energy vectors.
Synthesis and Thermal decomposition study of Dysprosium Trifluoroacetate J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-19 Y.A. Opata, J.-C. Grivel
A study of the thermal decomposition process of dysprosium trifluoroacetate hydrate under flowing argon is presented. Thermogravimetry, differential thermal analysis, evolved gas analysis and ex-situ x-ray diffraction techniques have been employed in the investigation. Three main stages were identified: dehydration, decomposition and phase transformation from DyF3 to DyFO. The dehydration takes place in 2 steps and the decomposition also occurs in two stages. The observed residual mass demonstrated a discrepancy with the calculated value for DyF3 formation. Observations on quenched samples at temperatures just above the decomposition step and at 828 °C showed a variation in the sample color, being dark in the first case and rather bright at the higher quenching temperature. Based on this fact, we concluded that some carbon remains in the sample up to 800 °C. With the temperature reaching 1300 °C, a plateau is observed in the TG signal, which mass value agrees with the formation of DyFO as verified by the ex-situ x-ray data of quenched powder. Using the FTIR and MS spectra of released gases during the process and the TG data, a decomposition scheme is suggested.
THERMAL CRACKING OF N-BUTYLBENZENE AT HIGH PRESSURE: EXPERIMENTAL STUDY AND KINETIC MODELLING J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-15 N.C. Leguizamon Guerra, J.C. Lizardo Huerta, C. Lorgeoux, R. Michels, R. Fournet, B. Sirjean, A. Randi, R. Bounaceur, V. Burklé-Vitzthum
Chemical recycling of crosslinked poly(methyl methacrylate) and characterization of polymers produced with the recycled monomer J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-15 Rayany Stôcco Braido, Luiz Eduardo Pizarro Borges, José Carlos Pinto
The chemical recycling of crosslinked poly(methyl methacrylate) wastes, PMMA, used as dental resins, was investigated for recovery and polymerization of the methyl methacrylate monomer, MMA. At temperatures of 400 °C in laboratory and pilot plant installations, PMMA could be depolymerized by pyrolysis to produce more than 90 wt% of liquid, containing more than 98 wt% of MMA. Gas chromatography (GC) and coupled gas chromatography – mass spectrometry (GC–MS) analyses were carried out to characterize the obtained liquid fraction. PMMA powders produced with different quantities of recycled MMA were prepared, after purification of the liquid through distillation, leading to polymer resins with properties that were similar to the ones obtained with virgin commercial MMA, as characterized by particle size, Fourier transform infrared (FT-IR), gel permeation chromatograph (GPC) and scanning electron microscopy (SEM) analyses.
Sludge as a Relinquishing Catalyst in Co-Pyrolysis with Palm Empty Fruit Bunch Fiber J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-13 Li Wen Chow, Shu Anne Tio, Jia Yun Teoh, Chu Gen Lim, Yen Yee Chong, Suchithra Thangalazhy-Gopakumar
Co-cracking of bio-oil distillate bottoms with vacuum gas oil for enhanced production of light compounds ☆ J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-13 Yong S. Choi, Yaseen Elkasabi, Paul C. Tarves, Charles A. Mullen, Akwasi A. Boateng
Seamless co-processing of pyrolysis bio-oil within existing petroleum refineries is the most synergistic and economic way to improve biorefinery output. Coprocessing bio-oil with vacuum gas oil (VGO) is one logical pathway. Bio-oil has a viscosity and molecular weight range similar to that of VGO, and the hydrogen-rich nature of VGO can chemically complement the bio-oil hydrogen deficiency. Distillation of biomass pyrolysis oils produces solid residues with a significant fraction of fixed carbon and heavy volatiles. Maximization of yields of light compounds like olefins and gasoline-range aromatics are crucial for both attainment of desired product output levels as well as to follow methods that mimic petroleum-based methods and chemistries. Herein we discuss a systematic study on the additive coprocessing of specific bio-oil distillation bottoms with VGO. Tail-gas reactive pyrolysis (TGRP) bio-oils from spirulina, switchgrass, and guayule biomasses were distilled, and their bottoms were subject to analytical experiments in mixtures with VGO over different zeolite catalysts (no catalyst, HZSM-5, Y-zeolite). Switchgrass-based bottoms exhibit greater hydrogen deficiency and higher oxygen content compared with that of spirulina or guayule. Switchgrass-based bottoms, with or without VGO, produced more aromatics and less olefins and alkanes, compared with spirulina or guayule bottoms. When compared across different mixing ratios, thermal cracking of a 10:1 guayule/VGO mixture resulted in higher aromatics yields than even the VGO by itself. Addition of more VGO up to a 1:1 ratio of VGO/switchgrass bottoms nearly tripled the production of BTEX compounds. For hydrogen-rich bottoms spirulina and guayule, LPG-range olefins yields increased nearly 50% for 1:1 VGO/bottoms blends, compared with theoretical yields.
Prediction of elemental composition, water content and heating value of upgraded biofuel from the catalytic cracking of pyrolysis bio-oil vapors by infrared spectroscopy and partial least square regression models J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-12 A. Veses, J.M. López, T. García, M.S. Callén
Thermochemical conversion of sugarcane bagasse by fast pyrolysis: High yield of levoglucosan production J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-12 Geraldo F. David, Oselys Rodriguez Justo, Victor Haber Perez, Manuel Garcia-Perez
Ex-situ catalytic microwave pyrolysis of lignin over Co/ZSM-5 to upgrade bio-oil J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-10 Wei Xie, Jianghui Liang, Hervan Marion Morgan Jr., Xiaodong Zhang, Kui Wang, Hanping Mao, Quan Bu
The present study aims to produce bio-fuel from lignin via catalytic upgrading of vapors from lignin microwave pyrolysis. The effects of cobalt modified ZSM-5 catalysts on products yield and chemical selectivity of bio-oils were investigated. A central composite experimental design (CCD) was used to optimize the reaction conditions for bio-fuel production. The effects of the reaction temperature and ratio of catalyst to lignin on products (bio-oil, gas and volatiles) yield distribution and chemical composition of bio-oil were investigated. Response surface analysis indicated that the obtained models were able to predict the products yield distribution and the major chemical compound distribution of the bio-oil. GC/MS analysis revealed that the main chemical compounds were ketones, furans, phenols and guaiacols, which accounted for more than 85% in the detected bio-oil. GC analysis showed that the major components of the gas were H2 and CO (about 60%).
Stability of crude bio-oil and its water-extracted fractions J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-10 Shoujie Ren, X. Philip Ye
Fractionation of crude bio-oil into an organic phase and an aqueous phase by simply adding water and research strategies targeted at producing hydrogen, fuels, or other value-added chemicals from the fractions have been proposed. However, the stability of the bio-oil fractions has not been comprehensively investigated. The objective of this study was to comparatively investigate the stability of crude bio-oil and its two fractions by evaluating their physicochemical properties during long-term storage at room temperature and accelerated aging at 40 °C and 60 °C. Comparing with crude bio-oil, the resulted aqueous phase is more stable; for the organic phase, the stability is also improved in terms of the changes in viscosity and average molecular weight, but not in terms of the increasing water content and total acid number. In overview for all the crude bio-oil and its two fractions, the water content, viscosity, total acid number, and average molecular weight increased with the increase of aging time and temperature; except for acetic acid and propionic acid, which slightly increased in content at all aging conditions, all the other 13 measured chemical contents decreased with the increasing aging time and temperature, indicating that the aging process involved all the six chemical groups of anhydrosugars, carboxylic acids, alcohols, furans, ketones, and phenolics, accelerated at higher temperature.
Sulfur Removal from Petroleum Coke during High- Temperature Pyrolysis. Analysis from TG-MS Data and ReaxFF Simulations J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-10 Qifan Zhong, Qiuyun Mao, Jin Xiao, Adri van Duin, Jonathan P. Mathews
Petroleum coke (petcoke) contains high carbon and low ash qualities, but with an undesirably high sulfur content. High-temperature (>1000 K) calcination produces a coke, suitable for many industrial uses, with an acceptable S content. Here the sulfur removal behavior during high-temperature pyrolysis was evaluated by combining high-temperature thermogravimetric analysis with product gas mass spectrometry (TG-MS), and reactive molecular dynamics (ReaxFF) simulations. From the TG-MS data the pyrolysis temperature of >1000 K significantly affected the S rejection. Three petcokes under 1273–1773 K in six different particle sizes (≤6 mm) were pyrolyzed to determine the desulfurization initiation temperature and desulfurization extent. A non-uniform behavior across the particle size ranges was obtained. Six Qingdao petcoke samples with cut sizes of <0.038, 0.07–0.05, 0.11–0.09, 0.25–0.15, 1.18–0.88, and 5.00–6.00 mm all achieved a similar desulfurization extent (∼80%) at >1673 K. However, considerable variability was shown in larger particles (1.18–0.88 and 5.00–6.00 mm) for Qingdao, Zhenhai, and Qilu petcoke between 1473–1773 K. The products included water (presumably from coke quench, 350–410 K), volatiles (430–550 K), CO2 and H2 (>800 K, mainly), CO and SO2 (>1200 K, mainly), and trace quantities of CS2 (>1400 K). The stable sulfur-containing products of this petcoke during high-temperature pyrolysis were SO2 and trace amounts of CS2. However, COS and H2S pyrolysis products were absent or below the detection limits. The pyrolysis behavior was explored using ReaxFF on a macromolecular petcoke structure with the S atoms in thiophene-like functional groups. The mechanism of S loss, under the simulation conditions, involved molecular rearrangement and thermolysis into intermediate states (C2S and CNS) and COS. These were explored for 250 ps for 3000, 3500, and 4000 K with the constant volume/temperature (NVT) ensemble. The sulfur removal transformation during pyrolysis is generally followed: thiophene sulfur → COS, C2S, or CNS → HS → SO2 or CS2.
Catalytic upgrading of volatile from coal pyrolysis over faujasite zeolites J. Anal. Appl. Pyrol. (IF 3.471) Pub Date : 2018-03-09 Yujie Liu, Lunjing Yan, Yonghui Bai, Fan Li
Catalytic upgrading of volatile from coal pyrolysis is a promising approach to convert heavy components to light aromatic hydrocarbons. In this work, four faujasite zeolites with different porosity and acidity, NaY, HY and two dealuminated Y zeolites including hydrothermal treatment Y (HTY) zeolite and hydrothermal treatment-acid leaching Y (HTY-AL) zeolite, were studied to upgrade coal pyrolysis volatile using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results show that they can significantly improve the yield of light aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, and naphthalene (BTEXN). Compared to NaY and HY zeolite, HTY and HTY-AL zeolite have better catalytic performance for the formation of light aromatics, with the yield of BTEXN increases from 0.78 wt% (raw coal pyrolysis) to 3.63 wt% and 5.31 wt%, respectively. The polycyclic aromatics are cracked remarkably, especially for anthracene with cracking ratio around 60%. The excellent performance of dealuminated Y zeolites correlates directly with their wider range of pore size distribution and suitable acid properties. This work provides a feasible approach of optimizing the acid and textural properties of catalysts to upgrade coal pyrolysis volatile and obtain a high yield of BTEXN.
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