Production, Prospects and Potential Application of Pyroligneous Acid in Agriculture J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-15 Arshdeep Grewal, Lord Abbey, Lokanadha Rao Gunupuru
Pyrolysis of plant biomass is a promising way to produce charcoal (solid), tar and pyroligneous acid, and other gaseous products. These products are of great import as they are alternative to traditional fuels and inorganic chemicals. In this review, main emphasis has been given to properties of pyroligneous acid and its potential benefits in agriculture. Pyroligneous acid is a crude condensed, highly oxygenated organic liquid which is a by-product of pyrolysis of plant biomass. It mainly consisted of aliphatic, aromatic, and naphthenic hydrocarbons and other oxygenated compounds such as alcohols, aldehydes, ketones, furans, acids, phenols and ethers. Pyroligneous acid exhibits antioxidant and scavenger properties and has been used in agriculture as antimicrobial agent, insecticide, and seed germination and plant growth. This review takes a critical look at some of the production principles, roles of pyroligneous acid in plant growth, development and defense, and the prospects and broader application of pyroligneous acid in agriculture. It is envisaged that this review will generate global discussion and create awareness for the numerous opportunities in pyroligneous acid research and global use.
High-pressure pyrolysis of isoprenoid hydrocarbon p-menthane in a tandem micro-reactor with online GC-MS/FID J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-14 Siyuan Gong, Yutong Wang, Hongyan Wang, Xiangwen Zhang, Guozhu Liu
Isoprenoids have been synthesized in large quantities through metabolic engineering method using some microorganisms as hosts and biomass as carbon resources. An isoprenoid cyclic hydrocarbon, p-menthane, is considered as a promising “drop-in” fuel to substitute traditional cycloalkane components, however, its pyrolysis data is lacking so far which is a significant part of the fuel combustion chemistry, especially under high pressures. In this work, pyrolysis experiments of p-menthane were carried out in a tandem micro-reactor under temperature of 450-800 °C and pressure of 2 MPa. 39 species were identified and quantified by online GC-MS/FID, based on which some initial pyrolysis pathways were determined. The early production of 4-methyl-1-cyclohexene and 1-isopropyl-1-cyclohexene indicates that methyl and isopropyl scission happen at the initial stage followed by H-transfer reaction and dehydrogenation. The activation energy Ea and pre-exponential factor A of the overall reaction were calculated as 225 kJ mol-1 and 1.17×1012 s-1, respectively. For secondary reactions, many conjugated dienes such as 1,3-butadiene and 2-methyl-1,3-butadiene and small olefins such as ethylene and propene are generated through the ring-opening pathways. Benzene and toluene are the most abundant products among aromatics detected which are formed through dehydrogenation and demethylation of some early species like 4-methyl-1-cyclohexene and side-chain scission of aromatics. A particular product 1,3-hexadien-5-yne was detected which is generated through ring-opening pathways followed by H-transfer and demethylation reactions and could isomerized to benzene. A lumped kinetic model was proposed to describe the pyrolysis of p-menthane which exhibited good agreement with the experimental data.
Hydrothermal Liquefaction of Typical Livestock Manures in China: Biocrude Oil Production and Migration of Heavy Metals J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-12 Hugang Li, Jianwen Lu, Yuanhui Zhang, Zhidan Liu
Thermal investigations of biologically important fused azaisocytosine-containing congeners and the crystal structure of one representative J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-12 Łyszczek Renata, Bartyzel Agata, Głuchowska Halina, Mazur Liliana, Sztanke Małgorzata, Sztanke Krzysztof
The thermal properties of nine biologically important fused azaisocytosine-containing congeners, e.g. 3-(thiophen-2-yl)-8-(R-phenyl)-7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-ones (1-9), were studied by means of different thermal analysis methods (TG-DTG-DSC and TG-FTIR). The influence of heating atmosphere (air and nitrogen) on the pathways of thermal decomposition was investigated. The thermal stability of the investigated compounds in air can be ordered (in relation to the substituent attached at the phenyl moiety and denoted as R) as follows: 2-CH3O < 2-CH3 < 2,3-(CH3)2 ≈ 2-Cl = 4-CH3 < H ≈ 3-Cl = 4-Cl ≈ 3,4-Cl2. The two-stage thermal decomposition of compounds 1-9 in air was preceded by the melting process. One significant mass loss was observed during compounds pyrolysis under nitrogen atmosphere. The main volatile products of compounds degradation such as: carbon oxides, carbon oxysulfide, ammonia, isocyanic acid and its derivatives as well as methane and aromatic hydrocarbons were identified by the FTIR spectra. The impact of substituent types on the thermal behaviour of the studied congeners was described. The crystal structure of 8-(2-methoxyphenyl)-3-(thiophen-2-yl)-7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-one (5) was determined by the single-crystal X-ray diffraction method.
Efficient Removal of Oil from Spent Hydrodesulphurization Catalysts Using Microwave Pyrolysis Method J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-10 Cheng Yang, Jialiang Zhang, Yongqiang Chen, Chengyan Wang
Spent hydrodesulphurization (HDS) catalysts generally contain about 20% oil, the presence of which hinders the metallurgical processes for recovering valuable metals. In this study, a new approach was developed to remove oil from spent HDS catalysts by microwave pyrolysis. Firstly, the effects of the pyrolysis temperature and time on removing oil were investigated using microwave and conventional pyrolysis. The results show that removing oil using microwave pyrolysis was superior to using conventional pyrolysis in terms of energy savings, speed, and removal ratio. Under the optimum pyrolysis conditions (700 °C, 30 min, and an inert atmosphere), about 64% and 25% removal of carbon and sulfur, respectively, and 25% weight loss were achieved with the proposed method, while using conventional pyrolysis, only 40% and 18% removal of carbon and sulfur, respectively, and 20% weight loss were achieved. The properties of the raw spent HDS catalysts and pyrolysis products, including their morphologies and elemental states, were investigated using SEM-EDS, XPS, and FTIR. The results of these analyses indicate that the proposed method not only removes oil efficiently, but can also remove elemental carbon from spent catalysts. Finally, the main components of recovered oil and gas were investigated using FTIR, GC-MS, and GC-TCD analyses.
Analytical characterization of artist’s paint systems based on emulsion polymers and synthetic organic pigments J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-10 Theodora Fardi, Valentina Pintus, Elli Kampasakali, Eleni Pavlidou, Manfred Schreiner, Giorgos Kyriacou
The identification of artworks’ constituent materials is a prerequisite for the development of appropriate art conservation methodologies, as well as for addressing authenticity issues. The present study focuses on the characterization of acrylic emulsion paints, with the use of Pyrolysis coupled with Gas Chromatography / Mass Spectrometry (Py-GC/MS), in combination with Fourier Transform Infrared in ATR mode (FTIR-ATR) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS). Commercial paints manufactured by Liquitex (USA) and Rembrandt series of Royal Talens (NL) were chosen for the study; the four paints selected contained the synthetic organic pigments, Hansa yellow (PY3), diketopyrrolopyrrole (PR264), phthalocyanine blue (PB15) or phthalocyanine green (PG7). The results provide clear evidence of recent changes in the paint formulations regarding the polymeric binder, with the addition of styrene to the co-polymer nBA/MMA. Furthermore, different dispersants/surfactants were detected within the paints from the two different brands. Additional information was acquired on the additives incorporated in the paint, such as UV absorbers, optical brighteners, antioxidants and biocides. With regards to the identification of the synthetic organic pigments, several new molecular fragments were recorded using the applied experimental set-up at 600 °C, as compared to previous works. The products formed by the pyrolysis of the pigments are presented and discussed, showing evidence of different thermal fragmentation pathways as regards the synthetic organic pigments, when mixed in the emulsion paints.
Microwave pyrolysis of pecan nutshell and thermogravimetric, textural and spectroscopic characterization of carbonaceous products J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-07 G. Durán-Jiménez, V. Hernández-Montoya, M.A. Montes-Morán, S.W. Kingman, T. Monti, E.R. Binner
Pyrolysis of methyl ricinoleate by microwave-assisted heating coupled with atomization feeding J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-06 Shangzhi Yu, Ying Duan, Xiaoning Mao, Qinglong Xie, Gaoxiang Zeng, Meizhen Lu, Yong Nie, Jianbing Ji
A stable high-temperature reaction site and the uniformity and speed of heating the feedstocks play a key role in pyrolysis processes. In this study, microwave-assisted heating coupled with atomization feeding was used to pyrolyze methyl ricinoleate (MR) for the efficient, continuous production of undecylenic acid methyl ester (UAME) and heptanal (HEP). The effects of feed mode, reaction temperature and preheating temperature on microwave-assisted pyrolysis (MAP) were examined. The maximum selectivities of HEP and UAME could reach 91.4 wt.% and 76.6 wt.%, respectively, at the reaction and preheating temperatures of 500°C and 150°C, respectively, using atomization feeding. The gas, liquid and solid products were determined by gas chromatography (GC), GC-mass spectrometry (MS) and Fourier transform infrared (FT-IR), and the gas, liquid and solid yield reached 7.0 wt.%, 89.0 wt.% and 0.1% wt.%, respectively, with an error of 3.9 wt.% at 500°C. The pyrolysis of MR via microwave-assisted heating coupled with atomization feeding was found to be more efficient than the conventional pyrolysis process. In addition, the theoretical and actual heat for MAP of MR was 1461 kJ/kg and 2629 kJ/kg at 500 °C, respectively. The material balance and heat analysis results can be used to guide the design of an amplifying device.
Potential of Pyrolysis of Spacecraft Solid Waste for Water Recovery and Plant-Growth Media Production J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-06 Jacey L. Payne, Nayan N. Bhakta, Sarah Lyons, Ruba A.M. Mohamed, C. Carroll Kenneth, Catherine E. Brewer
Manned spaceflight outside of low-Earth orbit requires significant advances in closed-loop life support systems, especially the recycling of solid and liquid wastes to produce oxygen, food, and fresh water. Here, moderate temperature (400-600 °C) slow pyrolysis was tested to transform a high-fidelity spacecraft solid waste simulant into nutrient-rich crop growth medium for food production in space, while recovering water and carbon dioxide. Qualitative results indicated that water recovered from a simple drying process was of poor quality. Produced biochars approximated the characteristics of saline-sodic soils with P, K and micronutrients, low nitrogen, and no meaningful heavy metals, which suggests applicability as growth media. Before being used as growth media, biochar would likely need to be rinsed to remove sodium and supplemented with a source of nitrogen. If uncatalyzed slow pyrolysis is to be used, observations suggest that the produced volatiles should be directly combusted and water recovered from the flue gas, rather than trying to condense and separate the watery bio-oil product. This proof of concept study determined that low-temperature pyrolysis can be used to generate biochar-based soil, which may support agriculture during spaceflight while recycling nutrients and water from waste materials.
Comparison between in-situ and ex-situ catalytic pyrolysis of sawdust for gas production J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-05 Xiaodong Huo, Jun Xiao, Min Song, Li Zhu
In this work, in-situ and ex-situ catalytic pyrolysis (CP) of sawdust by Ni-based and Cu-based catalysts are compared in a two-stage fixed bed reactor. Alkali metal K and alkaline earth metal Mg are used to modify the catalysts for comparison. The ex-situ configuration plays a more dominant role in reducing tar while increasing gas production for all catalysts. Reduced Ni shows the best catalytic activity for hydrogen production, obtaining 36.4 vol.% of hydrogen with a yield of 13.6 mmol/g-bio in ex-situ CP. With the increase of temperature, ex-situ CP has a more significant effect on improving gas product and reducing liquid product than in-situ CP. K presents better modification effect than Mg, resulting in a higher yield of gaseous products. Also, TG and Raman analysis indicate that K can decrease the amount of coke deposition on catalysts and make the coke easier to be removed.
Comparative investigation between co-pyrolysis characteristics of protein and carbohydrate by TG-FTIR and Py-GC/MS J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-05 Xiaoyu Wei, Xiaoqian Ma, Xiaowei Peng, Zhongliang Yao, Fan Yang, Minquan Dai
The interaction of mass ratios on the co-pyrolysis characteristics of protein with carbohydrate was studied by TG-FTIR and Py-GC/MS. Soybean protein and corn starch were chosen as the model compounds for the research. Iso-conversional model-free methods including FWO and KAS were used to study pyrolysis kinetics of blends. Pyrolysis kinetics displayed positive synergy in 70SP and negative synergy in 10SP and 30SP. Positive ΔH and ΔG was obtained for pyrolysis of all blends. Results displayed strong synergistic effect among functional groups and gaseous products including CO2, CH4, -COOH, C = C, H2O, CO, HCN, HCNO, NH3 and C-O from the TG-FTIR inspection. Maillard reaction enhanced the yields of cyclic ketones including five-membered and six-membered, O-heterocyclic compounds and N-heterocyclic compounds through the combination of N-containing products and carbonyl group in reducing sugar from Py-GC/MS analysis.
Catalytic Fast Pyrolysis with Metal-Modified ZSM-5 Catalysts in Inert and Hydrogen Atmospheres J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-05 Alexander R. Stanton, Kristiina Iisa, Matthew M. Yung, Kimberly A. Magrini
The objective of this work was to determine the impact of hydrogen-activating metals on catalytic fast pyrolysis over ZSM-5 with and without hydrogen addition. Ga-, Ni-, Cu-, Co-, and Pt-modified ZSM-5 catalysts with metal-to-aluminum molar ratios of 2 were prepared by incipient wetness method. The catalysts were evaluated for hydrocarbon and oxygenate yields and for deactivation by analytical pyrolysis (Py-GC-MS), and post-reaction catalysts for characterization were prepared in a larger fixed-bed reactor. In inert atmosphere, there was a linear correlation between both the hydrocarbon yield and coke formation and density of strong acid sites, and the main impact of the metals was occlusion of active sites in ZSM-5, leading to proportional reductions in hydrocarbon and coke yields. With the addition of hydrogen, several metals (Pt, Ni, Cu, Co) activated hydrogen and further reduced coke formation, leading to improvements in the ratio of hydrocarbons to coke. No metal-modified catalyst out-performed fresh unmodified ZSM-5 in terms of hydrocarbon yield; however, Ni/ZSM-5 and Cu/ZSM-5 in hydrogen produced comparable hydrocarbon yields to ZSM-5 while reducing coke formation.
Bio-char and bio-oil characteristics produced from the interaction of Enteromorpha clathrate volatiles and rice husk bio-char during co-pyrolysis in a sectional pyrolysis furnace: A complementary study J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-03 Shuang Wang, Ding Jiang, Bin Cao, Lili Qian, Yamin Hu, Lu Liu, Chuan Yuan, Abd El-Fatah Abomohra, Zhixia He, Qian Wang, Bo Zhang
Catalytic coal hydrogasification by cobalt-calcium catalyst in a pressurized fluidized bed: role of hydropyrolysis and catalysis process J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-09-01 Shuai Yan, Jianshu Zhang, Xiaoqiang Yan, Dengfeng Pan, Hui Ren, Xuan Qu
Coal pyrolysis, hydropyrolysis and hydrogasification were performed in a lab-scale pressurized fluidized bed with or without cobalt-calcium bimetallic catalyst (Co-Ca) to preliminarily discern the role of hydropyrolysis, Co-Ca catalyst and H2 in the course of coal catalytic hydrogasification (CCHG). The hydrogasification reactivity and chemical structure of the coal chars generated after hydropyrolysis were also analyzed by means of pressurized thermogravimetric analyzer (P-TGA), FT-Raman and FT-IR, etc. Results indicate that Co-Ca catalyst possesses catalytic depolymerization and hydrogenation effect on coal during hydropyrolysis, which resulted in the promoted yield of CH4, tar and the high hydrogasification reactivity of the generated char. Co-Ca catalyst alone and H2 alone are hardly to fracture the C = C bonds in condensed aromatic rings of coal, but the union of them yields a superior bonds cleavage ability. The catalytic cleavage of C-C bonds is the crucial step of CCHG at the temperature above 800 °C with the hydrogen pressure above 1 MPa. Moreover, the CCHG process over Co-Ca catalyst is discussed and the probable pathways of the catalytic cleavage of C-C bonds are proposed.
Fast screening for hydrolysable and condensed tannins in lignocellulosic biomass using reactive Py-GC/MS with in situ silylation J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-31 Marco Mattonai, Erika Ribechini
Rapid screening techniques for lignocellulosic biomass are required for the development of efficient conversion strategies in the field of biofuels and value-added chemicals. This is particularly true for tannins, which are highly valuable in the tannery and nutraceutical industries. In the present work, we propose a quick method based on reactive pyrolysis with in situ hexamethyldisilazane (HMDS) derivatization followed by GC/MS analysis for the qualitative determination of tannins in lignocellulosic biomass. Different pyrolysis times were used to study pyrolysis mechanisms of tannins. Reference compounds belonging to hydrolysable and condensed tannins, both in monomeric and polymeric forms, were used to select specific pyrolysis products that could be used as markers. When pyrolysis time was increased, hydrolysable tannins were found to be highly thermostable, while condensed tannins showed extensive degradation. An optimal pyrolysis time was determined to reduce the number of peaks and increase the abundances of the most characteristic components. The results were applied to assess the presence of tannins in four different biomass: oak gall nuts, hazelnut cuticles, grape seeds and pomegranate bark.
Activity of water in pyrolysis oil – experiments and modelling J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-30 Yannik Ille, Fabian Kröhl, Alexis Velez, Axel Funke, Selva Pereda, Karlheinz Schaber, Nicolaus Dahmen
Fast pyrolysis is an option to convert lignocellulosic biomass into a large fraction of liquid bio-oil besides some char/ash and non-condensable gas. When ash-rich material is used, this usually results in a higher water content of the pyrolysis oil and a possible phase separation. To avoid phase separation, fractional condensation systems have been developed. Choosing appropriate condensation temperatures is essential to adjust the desired water content and bio-oil composition. For the modelling of such systems, detailed knowledge about the phase equilibrium of bio-oils is necessary, especially when aerosol formation is considered. This study presents the development of a model that is capable of describing the highly non-ideal behavior of these complex biomass derived mixtures.Straw based bio-oils from the bioliq® fast pyrolysis process are investigated. The required vapor liquid equilibrium data is measured in a phase equilibrium cell. The results are used for the development of suitable surrogate mixtures by studying about 200 possibly suited components to represent the heavy fraction of the bio-oil. For the calculation of the activity coefficients the gE-model Modified UNIFAC is used. Experimental and calculated data is presented and compared, with the focus on the activity of water as a key property for the thermodynamic behavior. The measured activity of water validates its strong non-ideal behavior in bio-oil. For the bio-oil investigated in this work, and according to the predictions of UNIFAC, a pseudo component formed by 3 groups of aromatic alcohol and 12 aromatic carbons (as in 3,4,4'-biphenyltriol) shows the thermodynamic behavior that best represents the unknown fraction of bio-oil. Depending on the choice of the surrogate mixture, the results can differ more than 100 %. This demonstrates the importance of a carefully chosen model as an essential tool for simulating fractional condensation systems.
FTIR and GCMS analysis of epoxy resin decomposition products feeding the flame during UL 94 standard flammability test. Application to the understanding of the blowing-out effect in epoxy/polyhedral silsesquioxane formulations J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-30 Wenchao Zhang, Alberto Fina, Giuseppe Ferraro, Rongjie Yang
A novel method was developed for the sampling of volatiles produced by polymer decomposition during UL-94 standard flammability tests, allowing collecting, separating and analyzing the precise composition of the fuel mixture feeding the flame in the real flaming conditions. The system was validated on epoxy resin/Polyhedral Oligomeric SilSesquioxanes (POSS) and found extremely informative for the understanding of the flame retardancy mechanisms previously referred to as the “blowing-out effect”. Collected products were analyzed by infrared spectroscopy and gas chromatography/mass spectroscopy, to identify the gaseous and liquid decomposition products, allowing depicting a comprehensive decomposition pathway for the epoxy resin. Lightweight volatiles, gaseous at room temperature, showed limited differences as a function of DOPO-POSS (polyhedral oligomeric silsesquioxane functionalized with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), whereas mixtures of liquid products evidenced for dramatic changes in the relative concentration as a function of DOPO-POSS. In pristine epoxy resin, the most abundant products were recognized as benzene, phenol, naphthalene and toluene, along with several tens of other aromatic products observed in lower amounts. The presence of DOPO-POSS at low concentration (2.5%) radically changes the composition of the aromatic volatiles mixture, as no significant amount of benzene is produced, while phenol becomes the main product, accounting for about half of the total, isopropyl phenol and bisphenol A, along with several tens of other products in lower concentrations. Such modification of the fuel mixture feeding the flame provided an explanation for the lower flammability of this formulation, as well as for the phenomenology of the blowing out effect.
Experimental and Computational Investigation on the Decomposition Kinetics and Uni-Molecular Degradation of (Z)-N,2,2,2-tetranitroacetimidic acid J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-28 Parimi Ashutosh, Anuj A. Vargeese
Tetranitroacetimidic Acid (TNAA) is a potential environmental friendly energetic oxidizer, which exhibits keto-enol tautomerism and a peculiar decomposition behavior. The decomposition process was first experimentally analyzed by using thermogravimetry (TG), differential scanning calorimetry (DSC) and then, theoretically evaluated the stability of different tautomeric forms of the molecule. Calculations are done in the gas-phase to understand the decomposition phenomenon, the removal of nitro groups and the proton shift is mainly targeted in this study. The study has identified the tautomer which undergoes the high temperature thermal decomposition. The kinetic analysis showed unification of the multistep reactions and is supported by the computational studies. Interestingly, TNAA is found to exhibit three different interchangeable structures and the cleavage of N-NO2 bond requires more energy than that of C-NO2 bond cleavage. The total energies of the radicals are analyzed and the possible pathway of decomposition is deduced with respect to the results.
Effect of chitosan on the fire retardancy and thermal degradation properties of coated cotton fabrics with sodium phytate and APTES by LBL assembly J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-27 Yun Liu, Quan-Quan Wang, Zhi-Ming Jiang, Chuan-Jie Zhang, Zhong-Fang Li, Hua-Qi Chen, Ping Zhu
Chitosan was added to cotton fabrics coated with sodium phytate and 3-Aminopropyl triethoxysilane (APTES) to further enhance the fire retardant property by the layer-by-layer (LBL) assembly. The surface morphologies before and after flaming and structure of coated cotton fabrics were evaluated by scanning electron microscopy and Fourier transform infrared analysis. The thermal degradation properties, fire retardancy, and combustion properties of this system were investigated by Fourier transform infrared analysis, thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) in the N2 atmosphere, the thermogravimetric analysis in air atmosphere, limiting oxygen index test (LOI), vertical burning test and cone calorimeter test, respectively. Sodium phytate, chitosan and hydrolyzed APTES were successfully deposited and well distributed on the surface of cotton fibers. The LOI value of the coated cotton fabric with 15BL was 29.0%, and it extinguished at once in the vertical burning test, while the coated cotton fabrics with 5BL and 10BL were burned out. The deposition of sodium phytate, chitosan and hydrolyzed APTES led to the decrease of heat release rate, total heat release, total smoke release and smoke production rate. The promoted fire retardancy was assigned to thermally stable residuals formed on the surface of cotton fibers, which prohibited heat/mass transfer from combustion zone to polymer degradation zone. TG-FTIR results indicated that flame retardant cotton fabrics produced more nonflammable gases (CO2 and H2O) and less combustible gases than them of the control sample did, increasing flame retardant properties of flame retardant cotton fabrics.
Fractional condensation and aging of pyrolysis oil from softwood and organosolv lignin J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-24 Alex Moutsoglou, Brian Lawburgh, James Lawburgh
Softwood and organosolv lignin were pyrolized in a fluidized bed reactor. In each case, fractional condensation was achieved through two cyclonic condensers, maintained at different temperatures, and separated by an electrostatic precipitator. The produced oil was analyzed for liquid yield, water content, acidity, calorific value, carbon-hydrogen-nitrogen-oxygen content, viscosity, and rheology. To assess the effects of aging on the quality of the bio-oil, these tests were repeated after one-, two-, three- and nine- month intervals. The organosolv lignin is found to provide lower oil yields (30%) than softwood (50%). It is shown that higher carbon and lower oxygen content in the feedstock correlates to better bio-oil quality. Lignin, with a higher carbon and lower oxygen content than softwood, results in bio-oil with less water, lower acidity, higher heating values, and higher dynamic viscosities. Increasing the condensing temperature of the first condenser delays the condensation of water and light organics in the condensing train, affecting the properties of bio-oil, especially for the softwood. Tests on aging of the bio-oil demonstrate that viscosity is the only property significantly affected by the shelf life of the oil. Present data are favorably compared with available published data, for both feedstock types.
SELF-CATALYZING PYROLYSIS OF OLIVE POMACE J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-24 Dinc Gamze, Yel Esra
In this study, catalytic effect of intrinsic inorganics was evaluated by comparing pyrolysis end products obtained from pyrolysis of olive pomace (OP) in three different initial weights (30,100 and 200 grams). Pyrolysis of OP with higher weights led to self-catalyzing pyrolysis resulting in approximately 20% bio-oil quantity increment when pyrolyzed OP weight increased from 30 grams to 200 grams. Additionally, both intrinsic inorganic percentages remained in pyrolysis chars and organic compounds in pyrolysis liquids altered with pyrolyzed OP weights. While the lowest inorganic percentage in chars was found at the pyrolysis of the highest OP weight, the highest belonged to 30 grams OP pyrolysis. Moreover, while oxygenated compounds, namely aldehydes and ketones, in pyrolysis bio-oil decreased explicitly at 200 grams OP pyrolysis, variety in alkane and alkene compounds enhanced at higher weights OP pyrolysis. Finally, the effects of temperature, heating rate and retention time on pyrolysis products were evaluated. Results showed that liquid products increased at 5 °C/min heating rate and decreased at 1 °C/min heating rate as pyrolysis temperature increased from 450 to 600 °C in the pyrolysis without retention time. However, reverse tendency was observed in liquid product quantities in the case of pyrolysis with retention time. Furthermore, while effect of temperature increment on pyrolysis gas and liquid was mostly opposite to each other in all pyrolysis conditions, bio-chars' quantity irregularly altered as to pyrolysis conditions.
Synthesis of a novel mono-component intumescent flame retardant and its high efficiency for flame retardant polyethylene J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-24 Siyu Xia, Zhiyong Zhang, Yang Leng, Bin Li, Miaojun Xu
Characterization and pyrolysis behavior of the green microalga Micractinium conductrix grown in lab-scale tubular photobioreactor using Py-GC/MS and TGA/MS J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-25 Shuang Wang, Benjamin Bernard Uzoejinwa, Abd El-Fatah Abomohra, Qian Wang, Zhixia He, Yongqiang Feng, Bo Zhang, Chi-Wai Hui
Co-deoxy-liquefaction of willow leaves and waste tires for high-caloric fuel production J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-25 Weipeng Lu, Yanchuan Guo, Bing Zhang
Sulfur is widely present in waste tires and causes difficulty to recycle waste tires as a fuel, while removal of oxygen in biomass is an important premise for its effective utilization. In this study, high caloric fuel (HCF) was prepared by co-deoxy-liquefaction of willow leaves and waste tires. The influence of mixing ratio (0-100%) and temperature (300-500℃) on the product yields and chemical compositions of HCF were investigated. Results showed that the HCF obtained at 400 ℃with mixing ratio of 80/20 (willow leaves : waste tires, m/m) possessed the highest HHV (45.52 MJ/kg), highest alkane content (56.24%) and lowest oxygen content (1.79%). Preliminary analysis of mechanisms indicated that co-deoxy-liquefaction of the mixture inhibited the formation of liquid sulfur compounds, with much of the S element being eliminated from waste tires in the form of SO2, thus improving the quality of the HCF. Experiments also suggested that the overall efficiency of the deoxy-liquefaction of biomass and the desulfur-liquefaction of waste tires were both enhanced by adding waste tires to biomass. So, co-deoxy-liquefaction of biomass and waste tires presents a promising way of producing high caloric fuel with high quality in the future.
Effects of low-temperature rapid pyrolysis treatment on the improvement in caking property of a Chinese sub-bituminous coal J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-25 Xiangchun Liu, Qiang Ling, Zhigang Zhao, Ruilun Xie, Delei Yu, Qingping Ke, Zhao Lei, Ping Cui
We proposed a low-temperature rapid pyrolysis treatment (LTRP) to modify the caking property of a sub-bituminous coal. The coal was thermally treated in a rotating furnace in the temperature range 320–500 °C at a heating rate of ca. 80 °C/min. We also conducted an integrated investigation on some physicochemical properties, which were characterized by ultimate analysis, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, pore volume, scanning electron microscopy, and thermogravimetry, of the treated coal to determine the modification mechanism. Caking and coking properties were evaluated by caking index (G) and crucible coking experiments, respectively. The results showed that LTRP significantly increased G, which reached the maximum at 410 °C, implying the existence of an optimum temperature. Crucible coking experiments showed that structure strength and micro-strength indices of the resulting cokes were also improved by LTRP treatment. A mechanism was proposed for the modification of the caking property. Suitable upgrading degree with suitable molecular masses and low melting donor hydrogen rich species presented within the coal, which dominated the development of caking property, was important. The synergistic effect of pore volume and the contents of total acidity groups, volatile matter, hydrogen, and oxygen in the coal determined the suitable upgrading degree.
New complexes of light lanthanides with the valsartan in the solid state: Thermal and spectroscopic studies J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-25 Bruno Ekawa, Wilhan Donizete Gonçalves Nunes, José Augusto Teixeira, Marco Aurélio Cebim, Elias Yuki Ionashiro, Flávio Junior Caires
New lanthanides complexes with valsartan drug (H2Val) with stoichiometry Ln2(Val)3⋅nH2O (Ln = La, Ce, Pr, Nd and Sm) were obtained by reacting a solution of the lanthanide nitrate with a solution of valsartan sodium salt. The complexes were characterized by simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) in dry air and nitrogen atmospheres, Evolved gas analysis (EGA) by TG-DSC-FTIR, Elemental Analysis (EA), complexometry with EDTA, Fourier transform Infrared and Raman (FTIR and FT-Raman) spectroscopy, UV-Vis spectroscopy and Powder X-Ray Diffraction (PXRD). The thermal decomposition of the complexes differed in dry air atmosphere with four steps for Ce, five for La and Pr and six for Nd and Sm. In nitrogen atmosphere all the complexes had a similar behavior, with three mass loss steps up to 1000 °C, leading to the formation of a mixture of carbonized material and metal oxide. The main gaseous products released during the thermal decomposition of these compounds were nitrous oxide, carbon dioxide and carbon monoxide (in air atmosphere), ammonia, nitrous oxide, carbon dioxide, carbon monoxide, and an unsaturated ketone or a mixture of unsaturated hydrocarbon and a ketone (in nitrogen atmosphere). The PXRD data suggest that the compounds are amorphous; the FTIR spectra suggests coordination of the ligand by the tetrazole ring, and by the carboxylate group as monodentate ligand; finally, the UV-Vis spectra of the Pr, Nd and Sm complexes provided information about the degree of covalence of each compound.
Integration of time and spatially resolved in-situ temperature and pressure measurements with soft ionisation mass spectrometry inside a burning superslim cigarette J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-26 Huapeng Cui, Sven Ehlert, Fuwei Xie, Jan Heide, Nan Deng, Bin Li, Chuan Liu, Kevin McAdam, Andreas Walte, Ralf Zimmermann
Background Accurate diagnostics of key thermophysical and thermochemical parameters in multi-phased combustion phenomena is essential for understanding formation mechanisms of reaction products. Aim To combine simultaneous temperature and pressure measurements with fast in-situ chemical sampling techniques within a superslim cigarette to: (1) obtain detailed physical and chemical information from this dynamic combustion system in response to an externally applied air flow, and (2) demonstrate the comprehensive capabilities of the approach in deducing mechanistic information about complex chemical reactions. Methods A micrometre sampling stage was used to accurately position the in-situ sampling probes for insertion into the cigarette. An array of 0.254-mm thermocouples (for gas-phase temperature) and multiple 0.35-mm diameter quartz tubes connected to transducers (to measure pressure), were inserted into the superslim cigarette. For chemical analysis, a single heated 0.5-mm chemical sampling microprobe was also inserted, and coupled to a single-photon soft ionisation (SPI) mass spectrometer through a heated transfer line. The different measurement techniques were synchronised by mapping two probes at a time (e.g. temperature/pressure or temperature/chemistry); the physical and chemical events were visualised and mapped using dedicated software to integrate the various data sets. Results The highly heterogeneous combustion system was characterised using a series of temperature, gas flow velocity maps. The complex and dynamic variations in thermochemical events occurring within the cigarettes were monitored by following three marker compounds, NH3, indole and nicotine. The time- and spatially resolved formation maps for these compounds illustrated the operation of thermal desorption, pyrolysis and combustion-led processes within the cigarette, following application of an externally applied air flow. Conclusion By integrating two physical sensors with fast chemical sampling, the burning of a superslim cigarette has studied in-situ in unparalleled detail. The experimental setup enabled complex combustion diagnostics within a confined but dynamic geometry.
Demethylation as a mechanism for isotopic reversals of shale gas generated at over maturity J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-23 Jingkui Mi, Huitong Wang, Kun He, Jingfang Bai, Changyue Liu
This paper investigates demethylation as a possible mechanism leading to isotopic reversals of shale gas during the thermal degradation using a model compound representative of methylated monoaromatic hydrocarbons presented in over-mature organic matter. The model compound used is 1,3,5-Trimethylbenzene (TB), which was subjected to isothermal pyrolysis experiments at three temperatures of 400 °C, 425 °C and 450 °C holding from 24 to 480 hours at 300 bar. During the process of TB pyrolysis, heavy hydrocarbon gas was generated in addition to methane and hydrogen. Some aromatic compounds-bearing ethyl and propyl were also detected in the liquid products. The series of carbon isotope of hydrocarbon gas shows a reversal feature (i.e. δ13C1>δ13C2) at TB conversion below 80%. The reversal feature is replaced by normal isotopic distribution when the TB conversion is above 80%. According to the yields variation of different products during TB cracking, heavy hydrocarbon gas appears to have generated via two pathways, (1) combination among the CH3 radicals from demethylation and (2) cleavage of long aliphatic chains formed by combination between CH3 radicals and methyl linked on aromatic rings during TB cracking. The reversal of carbon isotope between CH4 and C2H6 was caused by carbon isotopic fractionation during the heavy hydrocarbon gas generation. The TB cracking experiments indicates that demethylation is one of the factors causing the isotopic reversals of shale gas generated at over maturity. The change of carbon isotope from reversal to normal distribution is attributed to the cracking of C2H6 generated at higher thermal dynamics. It is deduced that the phenomenon of isotopic reversal of shale gas would disappear and be replaced by normal isotopic distribution with further decreasing of natural gas wetness.
Flash vacuum pyrolysis of oxo-stabilised phosphonium ylides containing methoxythiophene and methylthiophene groups J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-23 R. Alan Aitken, Alasdair N. Garnett
Benzoic acid recovery via waste poly(ethylene terephthalate) (PET) catalytic pyrolysis using sulphated zirconia catalyst J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-23 Laura S Diaz-Silvarrey, Andrew McMahon, Anh N. Phan
Two-stage catalytic pyrolysis and debromination of printed circuit boards: Effect of zero-valent Fe and Ni metals J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-18 Chuan Ma, Tohru Kamo
Pyrolysis of poplar, cellulose and lignin: Effects of acidity and alkalinity of the metal oxide catalysts J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-18 Chenting Zhang, Xun Hu, Hongyu Guo, Tao Wei, Dehua Dong, Guangzhi Hu, Song Hu, Jun Xiang, Qing Liu, Yi Wang
This study investigated the effects of the acidity/alkalinity of seven oxides (Al2O3, SiO2, ZnO, K2O, MgO, CaO, La2O3) on the pyrolysis of poplar, cellulose and lignin. The results showed that the basic supports such as CaO and MgO promoted the formation of gaseous products. CO, CO2, and CH4 were the main gaseous products in the pyrolysis of poplar, cellulose and lignin, and CO was formed first, followed by CO2 and CH4. Some H2 was also formed from the dehydrogenation reactions over CaO with cellulose as the feedstock. The acidic oxides promoted the tar formation, while the basic oxides suppressed tar formation. The oxides like CaO could remarkably suppress the production of phenolic compounds. The coke formation over the basic oxides were also much more significant than that over the acidic oxides, and the tar from cellulose contributed more towards coking. The heating of the coke in inert gas released CO2, CO, H2, CH4 via probably decarboxylation/decarbonylation, dehydrogenation and etc. The coke from the pyrolysis of lignin was much more stable. CaO and La2O3 reacted with the CO2 produced in pyrolysis and form the carbonates, while MgO could not. The TPO–MS characterization showed that the coke species were multiple types over CaO, and a single type over MgO. The cellulose–derivatives and the lignin–derivatives have distinct effects on the structural configuration of the coke.
Sustainable N-containing Biochars obtained at Low Temperatures as Sorbing Materials for Environmental Application: Municipal Biowaste-Derived Substances and Nanosponges Case Studies J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-18 Anastasia Anceschi, Federico Guerretta, Giuliana Magnacca, Marco Zanetti, Paola Benzi, Francesco Trotta, Fabrizio Caldera, Roberto Nisticò
The use of high density polyethylene (HDPE) as a co-feeding feedstock on the catalytic pyrolysis of yellow poplar over over Al-MCM-48 and Al-MSU-F J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-18 Young-Kwon Park, Hyung Won Lee, Young-Min Kim
High density polyethylene (HDPE) was applied as a co-feeding feedstock on the catalytic co-pyrolysis (CCP) of yellow polar (YP) over mesoporous catalysts, Al-MCM-48 and Al-MSU-F. Compared to non-catalytic thermogravimetic (TG) analysis of HDPE, catalytic TG analysis of HDPE had a much lower decomposition temperature, 407 °C over Al-MCM-48 and 446 °C over Al-MSU-F. On the other hand, the decomposition temperatures of HDPE increased up to 460 °C over Al-MCM-48 and 492 °C over Al-MSU-F by applying a mixture of HDPE and YP as the feedstock on the catalytic TGA. The experimental yields of aromatic hydrocarbons on the CCP of HDPE and YP over both Al-MCM-48 and Al-MSU-F were much higher than their theoretical yields. Al-MCM-48 produced a larger amount of aromatic hydrocarbons on the CCP of HDPE and YP than Al-MSU-F and had a greater synergistic effect on the formation of aromatic hydrocarbons than Al-MSU-F at 600 °C. The higher synergistic effect was obtained by applying 3:1 YP/HDPE ratio in the feedstock, higher catalyst/sample ratio (4:1), and higher reaction temperature (600 °C).
Pyrolysis of three different categories of automotive tyre wastes: Product yield analysis and characterization J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-18 Rohit Kumar Singh, Biswajit Ruj, Anusua Jana, Sourav Mondal, Banibrata Jana, Anup Kumar Sadhukhan, Parthapratim Gupta
Thermal pyrolysis of three automobile tyre waste (ATW’s) - light vehicle tyre (LVT), medium vehicle tyre (MVT) and heavy vehicle tyre (HVT), was investigated in a thermogravimetric analyser and a batch reactor. Such investigations on the effect of the fractions of natural and synthetic rubbers on product yield and the type of tyres on the pyrolysis process and products have not reported in the literature. The product yields were influenced strongly by the reactor temperature with higher temperature favouring the formation of more gases and more char being formed at lower temperatures. The range of degradation temperature was found to be the smallest for LVT as it contained mostly natural rubber (NR), while it was the largest for HVT due to the presence of NR and synthetic butyl rubber(SBR), having widely different degradation temperatures. In the batch reactor, maximum liquid yields of 51%, 45% and 63.5% were obtained for LVT, MVT and HVT at the optimum temperatures of 650 °C, 750 °C and 750 °C respectively at a heating rate of 20 °C/min. The oil obtained from LVT shows high aromatic content while the oil from MVT and HVT has a high presence of napthelinic component. The reactor pressure profile showed that the LVT started producing the non-condensable gaseous fraction earliest due to faster degradation. More secondary reactions for MVT generated more gases, leading to the highest final reactor pressure and high concentration of non condensable gases. Gas chromatographic (GC) analysis indicated that H2, CO, CO2, CH4, C2, C3H8 and C4 were the main gases obtained for all type of tyre wastes. Cracking of heavier hydrocarbons to the lighter ones and H2 was more dominant in MVT, while this was least prominent in HVT, producing less H2 and added oil. The activation energies for the pyrolysis reaction of LVT, MVT and HVT wastes were estimated to be 53.185, 62.489 and 64.574 kJ/mol respectively.
The synergistic mechanism on microwave and MoS2 in coal pyrolysis J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-16 Jun Zhou, Lei Wu, Kun Liang, Qiuli Zhang, Yonghui Song, Yuhong Tian, Xinzhe Lan
Microwave pyrolysis has been widely studied as a new type of coal thermal processing. In this research, we applied different amounts of MoS2 to the coal microwave pyrolysis and observed the consequent product effects to see if a higher pyrolysis efficiency and tar quality can be achieved. The catalytic action of MoS2 in solid, liquid, and gas products was further studied using both conventional and microwave pyrolysis, and a synergistic mechanism of microwave and MoS2 for coal pyrolysis was proposed. In a self-developed coal-gas microwave co-pyrolysis system, Proximate and ultimate analysis methods, X-ray diffraction, Scanning electron microscopy, Energy dispersive spectrometry, Fourier transform infrared spectroscopy, Gas chromatography-mass spectrometry and Gas analyzer were all employed to test and analyze pyrolysis products. The experimental results showed that when the amount of MoS2 was 8.3%, in microwave pyrolysis, the yield of liquid product was 28.4% with the light oil yield of 67.55%, and the yield of hydrogen was 22.19%. Compared with conventional pyrolysis, conventional pyrolysis with 8.3%MoS2 and microwave pyrolysis, a tighter structure of solid product, a higher yield of liquid product with an obvious light oil content increase could be obtained. The content of hydrogen in gas product decreased, while the valuable content of gas (CH4+CO+H2) and calorific value increased. The contrast experiments of coal pyrolysis showed that there was a synergetic effect of microwave and MoS2, and it improved the coal pyrolysis efficiency and tar quality.
The thermal decomposition mechanism and kinetics of tenoxicam J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-16 You Jin-zong, Wu Cheng-jie, Wang Xue-jie
Tenoxicam (TNX) is a non-steroidal anti-inflammatory drug. Its thermal decomposition processes were studied with thermogravimetry and differential thermal analysis. The produced gaseous products and residues during decomposition were detected and characterized using Fourier transform infrared spectroscopy. Combining with the molecular bond order distribution obtained from the quantum chemistry calculation, the thermal decomposition mechanism of TNX has been speculated. The kinetic parameters for thermal decomposition, such as activation energy Eα and the pre-exponential factor A, were obtained using the ATSM E1641 method. The prospective lifetime of TNX was estimated using the ATSM E1877 method. The results indicated that the thermal decomposition of TNX is a three-stage process. During the first stage of thermal decomposition, the main part of the molecule, including sulfamide, thiophene and amide, decompose simultaneously, and to form gasifiable small molecules and carbonized residues. The initial decomposition temperature in either nitrogen or air is about 204 °C. For decomposition in nitrogen, the Eα and A for the initial thermal decomposition are 174.8 kJ mol-1 and 2.512 × 1017 min-1, respectively. For decomposition in air, the corresponding Eα and A are 179.4 kJ mol-1 and 7.943 × 1017 min-1, respectively. The TNX has good thermal stability under routine temperature.
TGA-FTIR analysis of upper assam oil shale, optimization of lab-scale pyrolysis process parameters using RSM J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-14 Bhargav Baruah, Pankaj Tiwari, Parash Thakur, Rupam Kataki
A pyrolysis approach for characterizing and assessing degradation of polyurethane foam in cultural heritage objects J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-15 Jacopo La Nasa, Greta Biale, Barbara Ferriani, Maria Perla Colombini, Francesca Modugno
Specific analytical tools are needed to investigate the composition and degradation processes of the synthetic materials in the cultural heritage, and recent advancements in pyrolysis-based analytical techniques have great potential for the characterisation of synthetic polymers. We applied evolved gas analysis mass spectrometry (EGA-MS) and double shot pyrolysis coupled with chromatography and mass spectrometry (Py-GC/MS) to investigate polyurethane foam micro-samples from the Italian pop-art sculpture “Contenitoreumano n.1” (1968) by Ico Parisi (1916-1996) and Francesco Somaini (1926-2005). The chemical analysis aimed to assess the chemical composition and of the state of preservation of the PU foam by acquiring information on its thermal degradation behaviour and identifying the pyrolysis products produced at different temperatures. A preliminary ATR-FTIR analysis was also carried out. The multi-analytical approach enabled us to identify the isocyanate and polyol precursors as 2,6-toluenediisocyanate and polypropylene glycol, respectively. The plasticizers used in the production of the PU foam were also identified in the first shot of a double shot Py-GC/MS experiment. A comparison of a sample of better preserved foam with a sample of degraded foam from the surface of the object highlighted that the more degraded part of the PU foam featured an increase in the thermal degradation temperature of the soft-fragments of the PU network, related to cross-linking phenomena. Moreover, loss of plasticizers and formation of NH2 functional groups was observed in the degraded foam.
Thermo-oxidative decomposition of lime, bergamot and cardamom essential oils J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-09 E. Jakab, M. Blazsó, E. Barta-Rajnai, B. Babinszki, Z. Sebestyén, Zs. Czégény, J. Nicol, P. Clayton, K. McAdam, C. Liu
The thermal decomposition of three essential oils has been studied at 300 °C, using a 9% oxygen in nitrogen atmosphere, to mimic the thermal environment of flavours under low-temperature tobacco heating conditions. The starting compositions of the lime, bergamot and cardamom oils were determined by gas chromatography/mass spectrometry (GC/MS). The thermo-oxidative decomposition was evaluated by applying on-line pyrolysis-GC/MS. The main constituents of the oils studied were cyclic and linear monoterpenoids; however, the relative intensities of these components were characteristically different between oils. Lime oil was dominated by monoterpene hydrocarbons, while the other citrus oil, bergamot oil contained in addition a significant number of esters and alcohols. Oxygen-containing monoterpenoids were the dominant constituents of cardamom oil. The relative proportion of the constituents of all three essential oil samples significantly altered during oxidative pyrolysis at 300 °C. The strained rings of bicyclic monoterpenes (pinenes, sabinene, and thujene) underwent scission, resulting in the formation of monocyclic monoterpenes (limonene etc.). Both linear and cyclic terpene acetates decomposed via elimination of acetic acid, so linalyl acetate produced myrcene and ocimene, while terpinyl acetate formed mostly limonene and terpinolene. The relative intensities of linalool and eucalyptol were reduced during pyrolysis, which can be explained by dehydration reactions resulting in the formation of myrcene and ocimene, or limonene and terpinolene, respectively. The chemical reactions that occurred were explained by bond splitting and intramolecular rearrangement mechanisms, with oxygen playing a role in the initiation processes.
ADVENTURES IN PYROLYSIS II, Modeling Pyrolysis Peaks of Petroleum Source Rocks J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-08 Richard J. Drozd
Programmed pyrolysis is an integral part petroleum source rock evaluation. The analysis is used to determine the potential of a source rock to generate further petroleum, and with other geochemical measurements, how much it may have generated in the past. An important part of the overall evaluation is an estimate of the source rock thermal maturity. Unfortunately, the addition of any extraneous, non-native hydrocarbons can negatively impact the yield of the samples, and more important, the thermal maturity determination. These extraneous hydrocarbons can be petroleum previously generated and retained within the source rock, fluids that migrated in the subsurface into the rocks, or organic material added during the drilling process. The objective of this study was to determine if mathematical methods could be used to remove these extraneous contributions from the true source rock yields, and arrive at a better determination of thermal maturity. Eighteen samples were studies using the standard pyrolysis method applied in the geochemical services industry. Two aliquots of each sample were analyzed: one as-received and a second after solvent extraction solvents to remove soluble organic matter but not kerogen. The pyrograms typically associate with the conversion of native organic matter in the rock were considered as the sum of up to three underlying components which could be recovered by non-linear least squares methods. Four distribution functions were used to model the pyrograms: classical Gaussian distribution, the Cauchy function, the Logistic function and the Weibull distribution. In addition to the ability of each model to match the measured data, each was evaluated for ease of use. All models reproduced the total pyrolysis yields of the test samples, and generated Tmax values with agreed within 2 °C. • The Gaussian model was marginally better at fitting the measurements than the Logistic or Weibull models, and distinctly better than the Cauchy model. Based upon experience, the Gaussian model was the most forgiving in the choice of initial parameters. • The Cauchy model performed the poorest at fitting the measurements and had the largest differences between extracted and unextracted Tmax values. The deviations from the measured values were most pronounced at high and low temperatures due the longer tail of the Cauchy function. • The Logistic model has marginally lower ability to fit the measured data than the Gaussian model, and similar to the Weibull model. However, the Logistic model was more sensitive to the choice of initial values than the Gaussian model, but less sensitive than the Weibull model. • The Weibull model was marginally poorer at fitting the measurements than the Gaussian model and similar to the Logistic model. It did less well at fitting the four component model for the more complex samples. It was most sensitive to the accurate choices for the initial conditions to insure convergence. For some samples sequential manual choices for these parameters was needed before the Gauss-Newton method could be employed.
Characteristics and inorganic N holding ability of biochar derived from the pyrolysis of agricultural and forestal residues in the southern China J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-08-03 Fen Liao, Yang Liu, Qiang Li, Yang-Rui Li, Li-Tao Yang, Mohammed Anas, Dong-Liang Huagn
Biochar not only provides an important way to utilize agricultural and forestry waste, but also plays an important role in soil improvement and soil carbon sequestration. This study mainly investigated the effect of pyrolysis temperatures(300, 500 and 650 °C) and feedstock types including Banana Leaf (BL), Banana Stalk (BS), Banana Pseudo stem (BP), Sugarcane Leaf (SL), Sugarcane Stalk (SS), Cassava Stem (CS), Mulberry Stalk (MS), and Eucalyptus Branches (EB) on the biochar properties an its inorganic N holding ability. The results showed that the physical properties of biochar were more affected by agricultural and forestal residues types e.g; herbaceous feedstock materials resulted in lower surface area (2-70 m2/g) while woody materials obtained relatively higher surface area (200-380 m2/g). However, the chemical properties of biochar were affected by pyrolysis temperature, as results indicated that BL biochar obtained pH 10.0 at 650 °C, while 8.45 at 300 °C, BS got highest CEC value 13.79 cmol kg−1 at 650 °C, while 6.83 cmol kg−1at 300 °C. NH4+-N sorption amount was ranging from 609.59 to 2040.40 mg/kg by different biochars, BS biochar adsorbed the highest amount of NH4+-N (1668.11 to 2040.4 mg/kg) among all the feedstock materials. Biochar derived from herbaceous biomass had relatively lower yield and C content as compared with that of wooden biomass. However, herbaceous biochars showed relatively better chemical properties than that of wooden biochars. The inorganic nitrogen holding ability of biochar was significantly affected by feedstock resources.
A study on catalytic co-pyrolysis of cellulose with seaweeds polysaccharides over ZSM-5: Towards high-quality biofuel production J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-31 Bin Cao, Zhen Xia, Shuang Wang, Abd El-Fatah Abomohra, Ning Cai, Yamin Hu, Chuan Yuan, Lili Qian, Lu Liu, Xinlin Liu, Bin Li, Zhixia He, Qian Wang
Microwave-assisted co-pyrolysis of microwave torrefied biomass with waste plastics using ZSM-5 as a catalyst for high quality bio-oil J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-31 Quan Bu, Yuanyuan Liu, Jianghui Liang, Hervan Marion Morgan, Lishi Yan, Fuqing Xu, Hanping Mao
This study aims to produce high quality bio-oil by microwave co-pyrolysis of torrefied biomass (rice straw) and low density polyethylene (LDPE) using ZSM-5 as a catalyst. A central composite experimental design was used to optimize the reaction condition by response surface methodology analysis. The effects of reaction temperatures and catalyst dosages on the product yield and chemical selectivity of bio-oil were investigated. Results suggested that bio-oil obtained from torrefied biomass contained a lower water content compared with the control.The major chemical compounds of bio-oil were hydrocarbons, ketones, phenols, esters and alcohols (~80%).Bio-oils with high hydrocarbon content (~40% in the bio-oil) were obtained in the development of this experiment. Quadratic models were used to predict the bio-oil yield and chemical selectivity of the bio-oil obtained during the reactions.
Pyrolysis of rapeseed oil cake in a fixed bed reactor to produce bio-oil J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-31 E. David, J. Kopac
With increasing environmental issues, production of bio-fuel represents a viable source of renewable energy and constitutes an alternative for the replacement of fossil fuel and reducing greenhouse gas emissions. In this paper, the effect of particle size, pyrolysis temperature, carrier gas flow rate (N2) was analyzed for obtaining of bio-oil from pyrolysis process of rapeseed oil cake. Optimum parameters obtained for the maximum liquid quantity and bio-oil yield (≈49.8% and 38.7%, respectively) were particle size range ≤ 0.5 mm, 500OC and 100 mL/min (N2) carrier gas flow rate. The calorific value of bio-oil was of 36.25 MJ/kg and the characterization of bio-oil was performed by FTIR, GC-MS and NMR and this demonstrates that can be a viable alternative fuel for public transport and agriculture sectors.
Surface Chemistry of Electronic Cigarette Electrical Heating Coils: Effects of Metal Type on Propylene Glycol Thermal Decomposition J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-26 Najat A. Saliba, Ahmad El Hellani, Edward Honein, Rola Salman, Soha Talih, Joseph Zeaiter, Alan Shihade
Bromine fixing ability of electric arc furnace dust during thermal degradation of tetrabromobisphenol: Experimental and thermodynamic analysis study J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-24 Mohammad Al-Harahsheh, Mohammednoor Altarawneh, Mohannad Aljarrah, Fahed Rummanah, Kameel Abdel-Latif
This work reports on the bromine fixing ability of a typical electric arc furnace dust (EAFD) upon its co-pyrolysis with tetrabormobisphenol (TBBA), the most widely used brominated flame retardant) both experimentally and theoretically following thermodynamic calculations. Experimentally, the following variables were considered in this investigation: EAFD: TBBA mass ratio (1:1, 1:2 and 1:3), pyrolysis heating rate and its final temperature and the effect of the NaCl and KCl presence in the dust. In the thermodynamic analysis the same parameters were studied excluding the heating rate. According to thermodynamic calculations, it was found that almost 100% of bromine, released as HBr during the thermal decomposition of TBBA, can be fixed by EAFD as metal bromides when 1:1 and 1:2 ratios where used. These metal bromides remain mainly in the solid form below 400⁰C; above this temperature they commence evaporation leaving the reaction system. At 1:3 ratio almost 10% of the initial bromine contents is released in HBr gaseous form. Experimentally, it was found that about 70% of HBr is captured by EAFD when 1:1 and 1:2 ratios were used at temperatures below 350⁰C, however, only 53% were captured when ratio 1:3 was used. At all conditions, the escaped gaseous HBr was as low as 6%. It was also found that high heating rates negatively affected the metal oxides ‘capacity to capture emitted HBr.
Soot formation during biomass pyrolysis: effects of temperature, water-leaching, and gas-phase residence time J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-24 Xuebin Wang, Shengjie Bai, Qiming Jin, Shuaishuai Li, Yukun Li, Yan Li, Houzhang Tan
Soot particles from biomass incomplete combustion, as a major source of particulate matter, arouse significant concerns due to its harmful impacts on environment and human health. In this paper, the effects of pyrolysis temperature, volatile residence time and water-leaching of biomass on soot formation during biomass pyrolysis were studied in a lab-scale furnace. The physicochemical characteristics of soot particles were comprehensively analyzed. Results show that soot is formed by the secondary reactions of volatiles from biomass thermal-cracking requiring a certain high temperature and long volatile residence time. With a short volatile residence time of 0.2 s, no soot is formed at 900-1200 °C. When the residence time increases to 2 s, soot is significantly formed at >1000 °C, when onion-like shell/core structures is observed. With pyrolysis temperature increasing, the soot particle size decreases and becomes uniform, the carbon content in soot increases, and the ordered structure of carbonization is enhanced, which leads to the degradation of soot oxidation reactivity. The water-leaching pretreatment for biomass leads to the increases of soot yield, particle size, and carbon content, as well as the KCl absence in soot and significantly lowered oxidation reactivity of soot. This indicates strong catalysis of potassium on soot production and consumption. Both gas and tar analyses support soot formation mechanism: (1) H2 yield increases due to formation of soot, but C2H2 yield reaches peak at 1000-1100 °C; (2) tar is dominated by PAHs, which molecules grow with the increase of temperature and residence time.
Characterisation and Py-GC/MS analysis of Imperata Cylindrica as potential biomass for bio-oil production in Brunei Darussalam J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-24 Hidayat Syarif, Muhammad S. Abu Bakar, Yang Yang, Phusunti Neeranuch, Bridgwater A.V.
Bio-oil production from renewable sources has been seen as suitable alternative to supply future energy demand. Perennials grasses are currently being developed as a suitable second-generation biofuel feedstock. It has advantages such as rapid growth rate, easy to grow, minimal maintenance and utilise marginal land without competing with food supply. Taking into account of the various challenges attributed to the transformation of second-generation biomass for energy production, this work systematically looks at the ecological perspective and the availability for bioenergy production from Imperata Cylindrica in Brunei Darussalam. Biomass characterisation was carried out to determine the properties and energy content, meanwhile py-GC/MS study was conducted to identify building blocks of value-added chemical from I. cylindrica. The physicochemical properties of feedstock was thoroughly evaluated using thermogravimetric analysis, proximate analysis, elemental analysis, compositional analysis, calorific value, and analytical pyrolysis interfaced with gas chromatograph (Py-GC/MS). Characterisation results indicate that Imperata Cylindrica has a calorific value of 18.39 MJ/kg, with low ash content and high percentage of volatile matter. Py-GC/MS analysis revealed the presence of furfural, 2,3-dihydrobenzofuran, 4-vinylguaiacol, propenylguaiacol, guaiacol and 4-ethylphenol. The fixed-bed pyrolysis experiment of imperata cylindrica showed that the yield of bio-oil increases with the increase of temperature and it reached a peak of 37.16% at 500 °C. These results show that Imperata Cylindrica is suitable as feedstock for bio-oil production via pyrolysis process.
Effect of process conditions on bio-oil obtained through continuous hydrothermal liquefaction of Scenedesmus sp. microalgae J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-23 Mariusz Wądrzyk, Rafał Janus, Mathijs P. Vos, Derk Willem Frederik Brilman
Hydrothermal liquefaction of biomass in near-/supercritical water has attracted great attention in recent years. Although this technology seems to be promising for transformation of microalgal biomass, the information on the impact of feedstock and processing variables of continuous hydrothermal liquefaction on the properties of bio-oil provided in previous literature is scarce. Herein, the low-lipid Scenedesmus sp. biomass has been transformed to bio-oils through continuous hydrothermal liquefaction under various process conditions. The influence of temperature and residence time on bio-oil characteristic was discussed based on characterization by FT-IR, GC–MS and gel permeation chromatography. The relative degree of branching of carbon chain of bio-oils components was estimated based on the deconvolution of methyl and methylene FT-IR absorption bands. The presumptive pathways of the reactions have been postulated. Finally, it was found that the parameters of bio-oil may be tailored by adjustment of processing variables, however, possible subsequent/parallel effects must be considered while designing the process.
Flash Vacuum Pyrolysis of Sulfamoyl Azides and Chlorides: Facile Gas-phase Generation of Transient N-sulfonylamines J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-23 Yan Lu, Hongmin Li, Huabin Wan, Qian Liu, Guohai Deng, Xiaoqing Zeng
Two sulfamoyl azides, H2NS(O)2N3 and MeN(H)S(O)2N3, have been isolated as neat substances and characterized. The solid-state structure of the parent molecule H2NS(O)2N3 has been established with X-ray crystallography. The thermal decomposition of both azides has been studied by combining flash vacuum pyrolysis (FVP, 400 °C) and matrix-isolation IR spectroscopy. In addition to the complete dissociation fragments for H2NS(O)2N3 (SO2, N2, and H2) and MeN(H)S(O)2N3 (SO2, N2, and CH2NH), the retro-ene decomposition products HN3 and N-sulfonylamines HNSO2 and MeNSO2 form, respectively. Alternatively, quantitative yield of both N-sulfonylamines in the gas phase occurs when sulfamoyl chlorides H2NS(O)2Cl and MeN(H)S(O)2Cl are used as the FVP precursors (400 °C). Consistent with these experimental observations, computational studies on the potential energy profiles for the decomposition of the two azides at the CCSD(T)/aug-cc-pVTZ//B3LYP/6-311++G(3df,3pd) level conclusively suggest that the N2-elimination is energetically more favorable than the HN3-elimination through either retro-ene reaction or 1,2-elimination. In contrast, the facile HCl-elimination from sulfamoyl chlorides provides a general method for the gas-phase generation of N-sulfonylamines, which were known as transient reactive intermediates in synthetic chemistry.
Py-GC/MS based analysis of the influence of citric acid leaching of sugarcane residues as a pretreatment to fast pyrolysis J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-21 Lizet Rodríguez-Machín, Luis E. Arteaga-Pérez, Jop Vercruysse, Raúl Alberto Pérez-Bermúdez, Wolter Prins, Frederik Ronsse
Sugarcane trash (SCT) and sugarcane bagasse (SCB) are prospective feedstock materials for fast pyrolysis. However, their relatively high inorganic content, especially alkali and alkaline earth metals (AAEMs), affects the quality of the produced bio-oil. This study evaluates the effect of SCT and SCB leaching by citric acid (CA) on the chemical composition of pyrolysis vapors, viz. by applying micro-pyrolysis (Py-GC/MS). Comparison was made between CA and well-known leaching agents including H2SO4, HCl and water. Accordingly, biomass samples were previously leached at different temperatures and leaching times. The results indicate that leaching with either citric acid or well-known inorganic acids causes the yields of levoglucosan in the pyrolysis vapors to increase by 5–8 fold. The mild structural changes in the lignocellulosic matrix, caused by hydrolysis during leaching, demonstrated to be as important for subsequent thermal degradation behavior (and thus increased anhydrosugars production) as the suppression of the intrinsic catalytic effect of the inorganic constituents by their removal during leaching. CA treatment generally favored the reduction in the total production of ketones and furans independently of leaching conditions (temperature, time). Differences in the range of leaching conditions tested (T = 25 – 50 °C; t = 1 – 12 h) had only minor influence on the composition of the pyrolysis vapors derived from CA pretreated sugarcane residues.
Two-stage ex-situ catalytic pyrolysis of lignocellulose for the production of gasoline-range chemicals J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-21 Devy K. Ratnasari, Weihong Yang, Pär G. Jönsson
The appropriate system is needed to produce a scalable and economically viable renewable energy from biomass. The objective of this study is to improve the quality of bio-oil, in terms of Organic Liquid Product (OLP), water content, acidity, favourable fractions, as well as gasoline-range chemicals. The influence of a staged layered catalyst system consists of a mesoporous catalyst, Al-MCM-41, and a microporous catalyst, HZSM-5, on the bio-oil quality was investigated. Additionally, the effect of reaction temperatures in the range of 400-600 °C with the optimum staged catalyst system on the catalytic pyrolysis product was analysed. The experiments of lignocellulosic biomass pyrolysis and catalytic pyrolysis were performed using a fixed bed reactor equipped with oil condensers and a gas collection sample bag. The quality of bio-oil produced from the thermal pyrolysis of lignocellulosic biomass, catalytic pyrolysis with single catalysts, catalytic pyrolysis with the staged catalyst system, as well as catalytic pyrolysis with mixed catalyst system was studied. The results show that Al-MCM-41 with HZSM-5 in the staged catalyst system enhanced the production of favourable compounds: hydrocarbons, phenols, furans, and alcohols. The favourable compounds yield that boosted 5.25-6.43% of that with single HZSM-5 catalyst was produced with HZSM-5:Al-MCM-41 mass ratio of 3:1 and 7:1. The pyrolysis and catalysis temperature of 500 °C with HZSM-5:Al-MCM-41 ratio of 3:1 obtained the optimum quality of bio-oil with 11.08 wt.% of OLP, 76.20% of favourable fractions, 41.97 wt.% of water content, low TAN of 43.01 mg-KOH/g, high deoxygenation, as well as high gasoline-range production of 97.89%.
Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-18 Jari Hyväluoma, Markus Hannula, Kai Arstila, Hailong Wang, Sampo Kulju, Kimmo Rasa
Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar porosity with x-ray tomography which provides quantitative information on the micrometer-range porosity. We imaged willow dried at 60 °C and biochar samples pyrolysed in three different temperatures (peak temperatures 308, 384, 489 °C, heating rate 2 °C min-1). Samples were carefully prepared and traced through the experiments, which allowed investigation of porosity development in micrometre size range. Pore space was quantified with image analysis of x-ray tomography images and, in addition, nanoscale porosity was examined with helium ion microscopy. The image analysis results show that initial pore structure of the raw material determines the properties of micrometre-range porosity in the studied temperature range. Thus, considering the pore-size regime relevant to the storage of plant available water, pyrolysis temperature in the studied range does not provide means to optimize the biochar structure. However, these findings do not rule out that process temperature may affect the water retention properties of biochars by modifying the chemical properties of the pore surfaces.
Enhancement of aromatics production from catalytic pyrolysis of biomass over HZSM-5 modified by chemical liquid deposition J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-18 Gongxin Dai, Shurong Wang, Shuqiong Huang, Qun Zou
The catalytic pyrolysis of biomass is a promising technology for producing high-quality fuels and value-added chemicals. However, the development of this technology has been hindered by high coke formation and low target product yield. In this study, chemical liquid deposition (CLD) was adopted to improve the catalytic performance of HZSM-5 in the catalytic pyrolysis of biomass. The changes of the characteristics, including crystallographic structure, porosity and acidity, of the HZSM-5 zeolite after modification were analyzed by XRD, N2 adsorption-desorption, FTIR and NH3-TPD. The results showed that CLD modification reduced the mesopore volume, pore opening size and the number of external acid sites without changing the micropore structure. Py-GC/MS (a pyrolyzer equipped with a gas chromatography-mass spectrometer) and kinetic analysis were used to analyze the catalytic performance of the parent and CLD-modified zeolites. It was found that the production of aromatics increased first and later decreased, reaching optimal levels at a 4% deposition of SiO2, while the selectivity of monoaromatics increased continuously. Additionally, CLD modification raised the energy barriers for the char/coke formation reactions and could inhibit its production. The deposition amount of 4% showed the best char/coke inhibitory effects for catalytic pyrolysis of cellulose, while the char/coke formation decreased continuously with the increase of the deposited amount of SiO2 for catalytic pyrolysis of lignin.
Thermo-oxidative degradation of aromatic flavour compounds under simulated tobacco heating product condition J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-17 M. Blazsó, B. Babinszki, Zs. Czégény, E. Barta-Rajnai, Z. Sebestyén, E. Jakab, J. Nicol, C. Liu, K. McAdam
A modified pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) method was used to evaluate the thermo-oxidative degradation of 34 flavour compounds containing aromatic sub-units, in 9% oxygen / 91% nitrogen at 300 °C with 5 min isothermal holding. This set of pyrolysis parameter was used to simulate heated tobacco products. The main types of reactions of these aromatic species under these conditions were relatively mild oxidation and thermal division resulting in the formation of benzaldehyde and other aldehydes, ketones, and styrene. The highest yield of these products was estimated to be around 10%, occurring where the molecular structure and reactivity of the compound was susceptible to oxidation or bond scission. Representative reaction schemes were proposed to explain the formation of the detected products. The results proved that styryl moiety present in some aromatic flavour compound did not decompose to styrene under the conditions applied, rather, styrene was generated from phenylacetic acid and phenylethyl esters by thermal cleavage at 300 °C.
Study on the pyrolysis of ammonium thiocyanate and its product formation characteristics in H2 J. Anal. Appl. Pyrol. (IF 3.468) Pub Date : 2018-07-17 Shuting Zhang, Guoqiang Li, Hongyu Wang, Chao Li, Tao Li, Yongfa Zhang
The thermal decomposition and products generation characteristics of ammonium thiocyanate (NH4SCN) have been studied in Ar and H2 by thermogravimetry - differential scanning calorimetry, thermogravimetry -Fourier transform infrared spectroscopy, Fourier transform infrared spectroscopy and X- ray diffraction. The results show that NH4SCN undergoes four endothermic processes between 40-850 °C in Ar and H2. The first two processes are dominated by the crystal transformation of NH4SCN, melting, and sublimation, and the isomerization of NH4SCN occurred in the third stage due to the pyrolysis process. H2 can inhibit the isomerization slightly and obviously promote the pyrolysis of NH4SCN. The pyrolysis end temperature in H2 was reduced to 603.80 °C, which is 120.55 °C lower than that using an Ar atmosphere. This difference is due to the higher thermal conductivity of H2 than Ar and the participation of H2 in the generation of HNCS and NH3. The main gaseous products are HNCS, NH3, CS2, and H2S. They were found to peak at 240.61 °C, which is 24.62 °C lower than in Ar. Thiourea, guanidine thiocyanate, cyanamide, dicyandiamide and melamine are main intermediates, while graphitic carbon nitride (g-C3N4) was formed at the end of pyrolysis.
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 3.468) 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 12.4wt.% in the carbonization stage of nitrogen atmosphere and 36.9wt.% in combustion stage of air atmosphere. Based on the 3D-FTIR analysis, the dominant components in the nitrogen atmosphere was CO2, CO bond contained organics, and CH or CO 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 CO 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.
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 3.468) 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.
Association of chemical structure and thermal degradation of lignins from crop straw and softwood J. Anal. Appl. Pyrol. (IF 3.468) 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.
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