The effects of various catalysts on the composition of volatile pyrolysis products of a plastic waste and biomass mixture (1:1) were studied, by pyrolyzing the mixture sample using slow and fast heating rate. Various zeolite catalysts (β-and Y-zeolites, ZSM-5 and FCC) and nickel-molybdenum catalyst on alumina support were applied to find suitable catalysts for upgrading the quality of the thermal decomposition products of the waste mixture. A sample to catalyst ratio of 2:1 was used in the experiments. The rate of evolution of the decomposition products under slow pyrolysis was measured by thermogravimetry/mass spectrometry (TG/MS). The composition of the pyrolyzates was analyzed in detail by pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) method. The influence of all applied catalysts was more pronounced on the plastic content of the sample than on biomass. The pyrolysis experiments revealed that the catalysts promoted the cracking reactions of the evolved hydrocarbons; furthermore, the formation of aromatic products was enhanced remarkably in the presence of all zeolite catalysts. Beta-zeolite and ZSM-5 catalysts were found the most effective in cracking hydrocarbons to gaseous products and in aromatization, while the highest CO 2 formation was obtained by FCC from the biomass part of the studied waste mixture. NiMo catalyst promoted the H 2 production from the plastic part; furthermore, slight aromatization and cracking effects were also observed.

•The effect of torrefaction and HTC was compared on Azolla filiculoides.•HTC at 260 °C resulted in more severe degradation than torrefaction at 300 °C.•Sources of aromatics are the most stable components during torrefaction and HTC.•Carbohydrate products and phytosterols derived from the thermally least stable parts.•Torrefaction mainly preserved the sources of aliphatics, but HTC hydrolyzed them.

The thermal decomposition of three essential oils has been studied at 300 degrees 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 degrees 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.

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 degrees 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 degrees C.

The chemical properties of laboratory-generated tar ball (Lab-TB) particles produced from dry distillate (wood tars) of three different wood species in the laboratory were investigated by analytical techniques that had never been used before for their characterization. The elemental compositions of laboratory-generated tar balls (Lab-TBs) from three tree species were very similar to one another and to those characteristic of atmospheric tar balls (TBs) collected from the savanna fire during the SAFARI 2000 sampling campaign. The O ∕ C and H ∕ C molar ratios of the generated Lab-TBs were at the upper limit characteristic of soot particles. The Fourier transform infrared spectroscopy (FT-IR) spectra of the generated Lab-TBs were very similar to one another as well and also showed some similarity with those of atmospheric humic-like substances (HULIS). The FT-IR measurements indicated that Lab-TBs have a higher proportion of aromatic structure than HULIS and the oxygen atoms of Lab-TBs are mainly found in hydroxyl and keto functional groups. Whereas Raman activity was detected in the starting materials of the Lab-TBs (wood tars) in the range of 1000–1800 cm−1, the Raman spectra of TBs were dominated by two pronounced bands with intensity maxima near 1580 (G band) and 1350 cm−1 (D band), indicating the presence of sp2-hybridized carbon structures and disorder in them, respectively. In the Py-GC-MS chromatograms of the Lab-TBs mostly aromatic compounds (aromatic hydrocarbons, oxygenated aromatics and heterocyclic aromatics) were identified in accordance with the results of Raman and FT-IR spectroscopy. According to organic carbon ∕ elemental carbon (OC ∕ EC) analysis using EUSAAR_2 thermal protocol, 22 % of the total carbon content of Lab-TBs was identified as EC, contrary to expectations based on the current understanding that negligible if any EC is present in this sub-fraction of the brown carbon family. Our results suggest that spherical atmospheric TBs with high C ∕ O molar ratios are closer to BC in many of their properties than to weakly absorbing HULIS.

The catalytic effect of HZSM-5 zeolite was studied on the thermal decomposition of model waste mixtures of plastics and biomass. The influence of temperature and catalyst ratio as well as the hindering effect of cellulose and lignin on the catalytic decomposition of plastic waste was studied applying low and high heating rate by thermogravimetry/mass spectrometry (TG/MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), respectively. HZSM-5 catalyst reduced the thermal stability of plastic waste, but the catalytic effect was blocked in the presence of 50% cellulose or 10% lignin. Principal component analysis (PCA) has been applied to reveal correlations between the composition of pyrolysis products, pyrolysis temperature and proportion of the applied catalyst. The hindering effect of biomass can be compensated by applying higher catalyst ratio.

An experimental method of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) is proposed to evaluate the fate of selected flavour compounds in low-temperature (300 degrees C) tobacco heating conditions. The thermal behaviour of five flavouring compounds (citronellol, menthol, tartaric acid, cinnamic acid, and guaiacol) was studied under conditions to simulate low-temperature tobacco heating at 300 degrees C, and compared with results obtained using simulated cigarette-combustion conditions with a temperature programme up to 900 degrees C. The impact of oxygen and nitrogen atmospheres on the thermal transfer and breakdown patterns was also investigated.It was established that the four flavouring compounds of high volatility (citronellol, menthol, cinnamic acid, and guaiacol) evaporated to a high degree (88-100%) during the low- and high-temperature experiments, as well. Guaiacol was the most stable compound under the test conditions; only 0.3% decomposition was detected at 900 degrees C with the oxidative atmosphere. Thermal decomposition reactions were substantially less extensive at the low-temperature heating conditions than with the high-temperature pyrolysis and simulated cigarette combustion. Citronellol and cinnamic acid produced about 1.5% decomposition products, while menthol produced 0.8%. In general, dehydrogenation reactions were more pronounced in the oxidative atmosphere, while aromatisation was significant in the nitrogen atmosphere, and at high temperatures. More oxo-compounds and less aromatic hydrocarbons were formed in the oxidative atmosphere.Other types of reactions took place with tartaric acid, due to its low volatility. Extensive formation of light carboxylic acids was observed at the low temperature, and cyclic compounds were also formed in addition to carbon oxides and Water under both nitrogen and oxidative atmospheres. Intermolecular reactions are proposed to explain these observations. At high temperatures the pyrolysis products of tartaric acid were the same as at low temperatures, but in the oxidative atmosphere more carboxylic acids and less aldehydes were formed than in pure nitrogen.These results demonstrate the flavour compound's thermal stability depends strongly on the exact thermal history (heating temperature, heating duration and gas atmosphere) that they are exposed to. The information obtained will be of interests in understanding the thermal behaviour of these and other flavour compounds used in tobacco heating products. (C) 2016 The Authors. Published by Elsevier B.V.

Autoroncsok motortereből szarmazo harom gumi minta osszetetelet es termikus tulajdonsagait tanulmanyoztuk termoanalitikai modszerekkel.

In this work the temperatures of the thermal decomposition of model waste mixtures were determined with and without catalysts under slow heating conditions applying thermogravimetry-mass spectrometry (TG/MS) technique. The catalytic effect of HZSM-5 and Ni-Mo catalysts were tested on the thermal stability of model waste mixtures. Significantly decreased thermal decomposition temperature (by about 200°C) was observed in case of plastic mixture in the presence of 10 % HZSM-5 catalyst. The catalytic effect of HZSM-5 catalyst was hindered when the domestic waste model mixtures contained biomass components as well. The effect of cellulose and lignin on the catalytic activity of HZSM-5 catalyst was tested and significant poisoning effect was observed in both cases. The presence of 50% cellulose or 10% lignin in the waste mixture completely deactivates the HZSM-5 catalyst.

The underlying chemical processes of the unexpected thermal decomposition behavior of poly(N-vinylimidazole)-l-poly(tetrahydrofuran) amphiphilic conetworks were investigated by thermogravimetric analysis and thermogravimetry-mass spectrometry.

Thermal decomposition of polyvinylchloride (PVC)–wood and wood component mixtures were examined under slow and fast heating by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and thermogravimetry/mass spectrometry(TG/MS) techniques in order to clarify the chemical interaction of biomass materials and PVC during thermal decomposition. A hardwood and a softwood (beech and pine), their lignin and two types of cellulose (Avicel and Whatman) were chosen as natural polymer components. Comparing the gaseous and liquid pyrolysis products of pure samples to those of mixtures it was found that considerably lower amount of several reactive compounds have been produced when the biomass sample was mixed with PVC. On the other hand significant amount of chloromethane appeared in the pyrolysate of wood and lignin samples mixed with PVC under fast and slow pyrolysis conditions as well, but only in traces of chlorinated organic compounds were detected from cellulose mixtures. It was concluded that the methoxy groups at phenolic rings in lignin are the methyl source of chloromethane formation, and this reaction consumed most of the HCl evolved from PVC.

In the present study, changes in the chemical structure of the components of deciduous wood species, i.e., birch (Betula spp.), aspen (Populus tremula) and grey alder (Alnus incana) wood, after hydrothermal modification (HIM) were investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and wet chemical analysis. The objective of this study was to elucidate the chemical changes in HTM deciduous wood dependent on the treatment parameters using chemical analysis and analytical pyrolysis and to evaluate the differences between the tree species. The results of both chemical and analytical pyrolysis studies demonstrate the effect of HIM on the chemical composition of deciduous wood. Wet chemical analyses showed that the hemicellulose content in wood decreased considerably (by 60-75%), whereas the cellulose and lignin contents increased by 6-20% and similar to 50%, respectively. The thermal destruction of hemicelluloses during HTM was also indicated by the water condensates, which contained acids and sugars. As a result of the HTM, wood transitions from a solid state to an aggregate state, in which the chemical composition of the gases (gas mixture) depends on the chemical composition of the wood. Py-GC/MS can quantitatively and promptly detect changes in the chemical composition of wood after HIM. As a result of the high HTM of wood above 160 degrees C, hemicelluloses are thermochemically destroyed and the primary products are acids (e.g., acetic acid and formic acid). Cellulose and lignin are more thermally stable than the hemicelluloses, as evidenced by the analytical pyrolysis results, which showed that the hemicellulose content in the wood decreased and the lignin content increased by revealing that the acid, ester and ether content in the gases decreased (by 24-33%) and the guaiacyl and syringyl derivative content increased (by 5-7%). Analytical pyrolysis is a promising method for understanding chemical transformations in HIM wood. (c) 2012 Elsevier B.V. All rights reserved.

The thermal decomposition of brominated epoxy oligomer (BrEpoxy)–natural polymer mixtures were examined by Py-GC/MS and TG/MS techniques in order to clarify the reactions between the components of the mixtures. The natural polymer components were: pine and beech wood, pine and beech milled wood lignin and two types of cellulose (Avicel and Whatman cellulose). It was found that the decomposition of both celluloses shifts to the temperature range of BrEpoxy decomposition. Significantly decreased formation of hydroxyacetaldehyde, hydroxypropanone and levoglucosan and increased yield of levoglucosenone was observed from cellulose–BrEpoxy mixtures. Drastically increased evolution of bromomethane was found from lignin or wood–BrEpoxy mixtures, indicating a radical scavenging reaction of lignin leading to the formation of bromomethane and phenoxy radicals.

Waste electric and electronic equipments (WEEE) and automotive plastic shredder contain nitrogen-containing polymers such as polyamides and polyurethanes. Thermal decomposition of these polymers leads to pyrolysis oil in which unwanted N-containing compounds are also present. Catalytic pyrolysis can be a way to reduce the oil's N-content or to obtain valuable products. We have examined the slow heating rate pyrolysis of zeolite–polyamide and zeolite–polyurethane mixtures by thermogravimetry-mass spectrometry (TG-MS), moreover flash pyrolysis of the mixtures at three different temperatures were carried out by pyrolysis-gas chromatography mass spectrometry (Py-GC/MS). In TG-MS experiments thermal decomposition characteristics of polyamides are hardly affected by the presence of acidic zeolites, nevertheless, MS ion curves show that the nature of the evolved volatile compounds have changed considerably. Similarly different pyrolysis products have been obtained from pure polyurethanes and polyurethane–zeolite mixtures, but polyurethane–zeolite mixtures have noticeably dissimilar thermal behaviour than the pure polymer. Py-GC/MS measurements have revealed that the pyrolysis temperature significantly affects the pyrolysis product distribution of the investigated polymers and also that of their mixtures with acidic zeolites. For zeolite–polyamide-6,6 1:1 mixtures it was concluded that hexanedinitrile is the main pyrolysis product and its predominance is the highest at 500°C. Main pyrolysis products of zeolite–polyamide-6 mixtures of 1:1 ratio are dihydro-azepine isomers. Their amount does not increase over 450°C, however with rising temperature aromatic compounds are also formed. In case of polyurethane–zeolite mixtures the ether and ester segments are decomposed mainly to monomers, while diisocyanate units are converted to N-containing aromatic compounds. The amount of these compounds is varying with temperature, moreover increasing the pyrolysis temperature (450°C or higher) the formation of aromatic hydrocarbons (benzene and naphthalene compounds) and light unsaturated hydrocarbons are favoured. Flash pyrolysis of polyurethane–NH4Y zeolite mixtures indicated that ammonia notably affects the decomposition of polyester segments leading to hexanedinitrile formation at as low temperature as 400°C.

A palyazat celjanak megfelelően műanyaghulladekokbol nyert pirolizisolajokat modositottunk szilard fazisu katalizatorok segitsegevel a nitrogen- es a halogentartalom csokkentese erdekeben. Megallapitottuk, hogy az Y es s zeolitok tobbnyire megvaltoztatjak a polimerek hőbomlastermek vegyuleteit, magat a hőbomlas reakciojat azonban kevesse befolyasoljak. Gyengen savas zeolit katalizatoragyon a pirolizistermek molekulak heteroatomot (nitrogent es oxigent) tartalmazo csoportjai leszakadnak, igy a pirolizatum nitrogentartalma a gazfazisba kerul, mig a szenhidrogen szegmensek egy- es ketgyűrűs aromas szenhidrogen vegyuletekke alakulnak. A natrium-zeolit kisebb molekulakra tordeli, es gyűrűbe zarja a hőbomlas termekeit, de nem bontja a szen-nitrogen koteseket; igy ez a katalizator alig csokkenti a pirolizisolaj nitrogentartalmat. A foszfortartalmu gyengen savas szervetlen egesgatlok jelentős hatassal vannak a polimerek hőbomlasi folyamataira es azok termekeire, azonban a pirolizisolaj nitrogentartalmat nem befolyasoljak. A natriumionos Y es s zeolitok altalaban alkalmasak a klor- es bromtartalmu pirolizisolajok halogentartalmanak merseklesere, de halogenmentesitő aktivitasuk jelentősen elterő a kulonboző tipusu szerves klor- es bromvegyuletek eseteben. Tanulmanyoztuk a deaktivalodott zeolitok regeneralhatosagat is. A katalitikus aktivitas elveszteset okozo szenes lerakodas minősege elterőnek bizonyult a protonos es a natriumion tartalmu zeolitoknal. | In accordance with the goals of the project pyrolysis oils of plastics waste have been converted over solid catalysts in order to decrease their nitrogen and halogen content. Our observations showed that the thermal decomposition reactions of polymers are hardly altered, but their products are mostly modified by Y and s zeolite. The heteroatom (N and O) containing groups of the pyrolysis product molecules are cleaved over zeolites of weak acidity, thus the nitrogen content of the pyrolysate is moved to the gas phase, while the hydrocarbon parts are converted to aromatic hydrocarbons of one and two rings. Over sodium-zeolites the pyrolysis product molecules are either split at C-C bonds or cyclised. But the C-N bonds are not cleaved, so the nitrogen content of the pyrolysis oil has hardly decreased over these zeolites. The inorganic phosphor containing flame retardants of weak acidity proved to influence the thermal decomposition process of the polymers, however, the nitrogen content of the pyrolysis oil has not been changed by them. Our experiments revealed that Na-Y and Na-s zeolite can be applied for dehalogenating pyrolysis oils of chlorine and bromine containing polymers, nevertheless their catalytic activity considerably differ for various types of organic chloro-and bromo-compounds. The regeneration of the deactivated zeolites has been also studied. The quality of the deposited coke proved to be different on the surface of protonated and sodium forms of zeolite.

The thermal decomposition of various mixtures of acrylonitrile butadiene styrene copolymer (ABS), ABS containing brominated epoxy resin flame retardant and Sb2O3, poly(ethylene terephthalate) (PET) and poly(vinyl chloride) (PVC) has been studied in order to clarify the reactions between the components of mixed polymers. More than 40 halogen-containing molecules have been identified among the pyrolysis products of mixed samples. Brominated and chlorinated aromatic esters were detected from the mixtures containing PET and halogen-containing polymers. A series of chlorinated, brominated and mixed chlorinated and brominated phenols and bisphenol A molecules have been identified among the pyrolysis products of polymer mixtures containing flame retarded ABS and PVC. It was established that the decomposition rate curves (DTG) of the mixtures were not simple superpositions of the individual components indicating interactions between the decomposition reactions of the polymer components. The maximal rate of thermal decomposition of both ABS and PET decreases significantly if the mixture contains brominated epoxy flame retardant and Sb2O3 synergist. The dehydrochlorination rate of PVC is enhanced in the presence of ABS or PET. (C) 2012 Elsevier B.V. All rights reserved.

A potential thermochemolysis reagent has been tested for the pyrolysis gas chromatographic identification of polyether, polyester and polyether- or polyester-based thermoplastic polyurethane. The main advantage of ammonium Y zeolite over liquid reagents is that it does not react prior to pyrolysis, and its reactions have no incomplete products. The procedure of the thermochemolysis is as simple as running a pyrolysis-GC/MS analysis sampling a powder mixture of roughly equal mass of polymer and ammonium Y zeolite. The GC/MS chromatograms obtained show that the products of thermochemolysis are specific to the diol and dicarboxylic units of the polymer. It was observed that ethanal or 1,4-dioxane forms from ethylene oxide components of polyethers and polyesters, tetrahydrofuran from butylene oxide units, hexanedinitrile from adipate groups, and benzodinitrile from terephthalate groups.