Schnellpyrolyse von Rohmontanwachs

Rapid Pyrolysis of Raw Montana Wax Montana wax of different origins has been subjected to rapid pyrolysis in a quartz apparatus according to the method reported by Romová?ek and Kubát, and the products of fragmentation have been identified chromatographically. The thermal splitting was generally carried out at 650° C, however, with the montana wax of Russian origin temperatures between 500° and 900° C were chosen. The individual products were identified and determined quantitatively.     

Thermal and catalytic pyrolysis of a synthetic mixture representative of packaging plastics residue

A synthetic mixture of real waste packaging plastics representative of the residue from a material recovery facility (plasmix) was submitted to thermal and catalytic pyrolysis. Preliminary thermogravimetry experiments coupled with Fourier transform infrared spectroscopy were performed to evaluate the effects of the catalysts on the polymers’ degradation temperatures and to determine the main compounds produced during pyrolysis. The thermal and catalytic experiments were conducted at 370°C, 450°C and 650°C using a bench scale reactor. The oil, gas, and char yields were analyzed and the compositions of the reaction products were compared. The primary aim of this study was to understand the effects of zeolitic hydrogen ultra stable zeolite Y (HUSY) and hydrogen zeolite socony mobil-5 (HZSM5) catalysts with high silica content on the pyrolysis process and the products’ quality. Thermogravimetry showed that HUSY significantly reduces the degradation temperature of all the polymers—particularly the polyolefines. HZSM5 had a significant effect on the degradation of polyethylene due to its smaller pore size. Mass balance showed that oil is always the main product of pyrolysis, regardless of the process conditions. However, all pyrolysis runs performed at 370°C were incomplete. The use of either zeolites resulted in a decrease in the heavy oil fraction and the prevention of wax formation. HUSY has the best performance in terms of the total monoaromatic yield (29 wt-% at 450°C), while HZSM5 promoted the production of gases (41 wt-% at 650°C). Plasmix is a potential input material for pyrolysis that is positively affected by the presence of the two tested zeolites. A more effective separation of polyethylene terephthalate during the selection process could lead to higher quality pyrolysis products.     

Characterization of the Organic Matter of Humic Acids by Pyrolytic Gas Chromatography–Mass Spectrometry

The results of the pyrolytic analysis of products of the organic matter of Sphagnum fuscum, fuscum peat, and humic acids separated from peat with the use of pyrolysis–chromatography–mass spectrometry in the Rock-Eval version are presented. It was shown that Sphagnum fuscum and peat differed only slightly in the degrees of chemical transformation. Benzene, phenol, and their alkyl-substituted homologues predominated in the thermal desorption products of humic acids upon pyrolysis to 400°C. Acetic acid, monohydric phenols, syringol, and guaiacol, which are the basic compounds in the high-temperature fraction, were formed on the pyrolysis humic acids to 700°C from the carbohydrate, phenylpropionic, and guaiacylpropane structural fragments.     

Investigations of the action of flame retardants in cellulose. II: Investigation of the flame-retardant action of polyphosphonitride in cellulose

Pure regenerated cellulose fibers and those containing various amounts of phosphorus nitride were pyrolyzed under different conditions in the temperature range of 150–440°C. Easily volatile liquid pyrolysis products, the tar fraction of limited volatility, and the charred residue were determined gravimetrically. The liquid volatiles were analyzed by combined gas chromatography/mass spectrometry for their water content. The tarnfraction and the charred residue were inspected by infrared (IR) spectroscopy. The studies revealed that the phosphorus nitride flame retardant enhances the onset of the pyrolytic decomposition and the release of water at substantially lower temperatures as observed for pure cellulose. The water release favors the carbonization and its extent reduces the formation of levoglucosan as a precursor of easily flammable pyrolysis products. Thus phosphorous nitride must be classified into the water release favoring flame retardants.     

Experimental and theoretical investigations of thermal degradation behaviors of poly(aryl ether sulfone)s

Density functional theory (DFT) calculation and pyrolysis gas chromatography mass spectrometry (PyGC/MS) analysis were combined to investigate the thermal degradation behavior of polysulfone, poly(ether sulfone) and poly(phenylene sulfone). A series of pyrolysis temperatures from 500°C to 700°C with the interval of 50°C were chosen for their PyGC/MS analyses, and the obtained results indicate that phenol as a pyrolysis product is preferentially generated over SO₂ during their pyrolysis. In DFT calculations, their bond dissociation energies and first-stage fragmentation products diradicals at various temperatures were calculated by the M05-2x method, and their preferentially produced pyrolysates estimated from the obtained results are in accordance with the experimental findings.     

Vacuum pyrolysis of polystyrene oligomers

Oligomers of polystyrene (PS) obtained from initial degradation studies of an anionic polymerized styrene have been degraded in vacuo using the molecular still method at temperatures between 150 and 250°C. The volatile decomposition products were separated and characterized by gel permeation chromatography, gas liquid chromatography, infrared spectroscopy, mass spectroscopy, and nuclear magnetic resonance. The products of pyrolysis showed that at 150°C the major component formed was the dimer, whereas at 250°C, the trimer was the major component. © 1993 John Wiley & Sons, Inc.     

Bio-oil from olive oil industry wastes: Pyrolysis of olive residue under different conditions

Olive residues were pyrolysed in a fixed bed reactor under different pyrolysis conditions to determine the role of final temperature, sweeping gas flow rate and steam velocity on the product yields and liquid product composition with a heating rate of 7 °C/min. Final temperature range studied was between 400 and 700 °C and the highest liquid product yield was obtained at 500 °C. Liquid product yield increased significantly under nitrogen and steam atmospheres. Liquid products obtained under the most suitable conditions were characterised by elemental analyses, FT-IR and ¹H-NMR. In addition, column chromatography was employed and the yields of the sub-fractions were calculated. Gas chromatography was achieved on n-pentane fractions. The results show that it is possible to obtain liquid products similar to petroleum from olive residue if the pyrolysis conditions are chosen accordingly.     

Bio-oil from olive oil industry wastes: Pyrolysis of olive residue under different conditions

Olive residues were pyrolysed in a fixed bed reactor under different pyrolysis conditions to determine the role of final temperature, sweeping gas flow rate and steam velocity on the product yields and liquid product composition with a heating rate of 7 °C/min. Final temperature range studied was between 400 and 700 °C and the highest liquid product yield was obtained at 500 °C. Liquid product yield increased significantly under nitrogen and steam atmospheres. Liquid products obtained under the most suitable conditions were characterised by elemental analyses, FT-IR and ¹H-NMR. In addition, column chromatography was employed and the yields of the sub-fractions were calculated. Gas chromatography was achieved on n-pentane fractions. The results show that it is possible to obtain liquid products similar to petroleum from olive residue if the pyrolysis conditions are chosen accordingly.     

Study on characterization of pyrolysis and hydrolysis products of poly(vinyl chloride) waste

Poly(vinyl chloride) PVC pyrolysis and hydrolysis are conducted in a fixed bed reactor and in an autoclave, respectively, under different operating conditions such as the temperature and time. The product distribution is studied. For the PVC pyrolysis process, the main gas product is HCl (55% at 340°C), there is 9% hydrocarbon gas (C₁–C₅), the liquid product fraction is about 5% (at 340°C), and the solid residue fraction is about 31% (at 340°C). For the hydrolysis process, the main gas product is HCl (55.8% at 240°C) and the solid residue is about 49.6% (at 240°C). The pyrolysis liquid product is analyzed by using gas chromatography with magic‐angle spinning. Aromatic hydrocarbons are the main class (90%), of which the major part is benzene (33%). The residue produced through pyrolysis and hydrolysis is investigated by high‐resolution solid‐state ¹³C‐NMR. These details revealed by the high‐field NMR spectra provide importmant information about the chemical changes in the PVC pyrolysis and hydrolysis process. The mechanism of PVC hydrolysis dechlorination is also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3252–3259, 2003     

Fixed-bed pyrolysis of cotton stalk for liquid and solid products

The pyrolysis of cotton stalk was studied for determining the main characteristics and quantities of liquid and solid products. Particular variables investigated were temperature (from 400 °C to 700 °C), particle sizes (from 0.25 mm to 1.8 mm) and nitrogen gas flow rate (from 50 and 400 cm³/min). All experiments were performed at a heating rate of 7 °C/min. The results showed that particle size and nitrogen flow rate did not exert a significant influence, whereas temperature was very significant. The liquid products and the subfractions of pentane-soluble fraction were characterized by elemental analysis, FT-IR spectroscopy, ¹H-NMR spectroscopy, and the pentane subfraction was analysed by gas chromatography. The characterization of char was performed in terms of its elemental composition, surface area and FT-IR spectroscopy. The H/C and O/C ratios of the chars decreased with the rise in the temperature. FT-IR showed that results the hydroxyl and carbonyl functionalities were lost at high temperatures. According to the experimental results the liquid products can be used as liquid fuels, whereas the solid products can be transformed to activated carbon for adsorption processes.     

Pyrolysis properties and kinetics of mandarin peel

The thermal property of the pyrolysis reaction of mandarin peel was studied using thermogravimetric analysis (TGA). Thermogravimetric analyses with temperature increases of 10, 20 and 40 °C/min showed large weight losses within the temperature range 150–590 °C. Differential thermogravimetric (DTG) analysis curves illustrated that the pyrolysis of mandarin peel was a multi-step process, consisting of water desorption, the decomposition of pectin, hemicellulose, cellulose and lignin, and devolatilization of the residual char. The apparent activation energies ranged between 119 and 406 kJ/mol, depending on the pyrolytic conversion. The pyrolysis products were analyzed, using pyrolyzergas chromatography/mass spectrometry (Py-GC/MS), to evaluate mandarin peel as a renewable source of valuable industrial chemicals. The pyrolysis products of mandarin peel contained high portions of methanol and acetic acid, as well as valuable compounds, such as limonene and vitamin E.     

The pyrolysis of cellulose and the action of flame-retardants

In further work on the vacuum pyrolysis of cotton cellulose, alone or with flame-retardants, at temperatures usually near 420°, products have been identified and determined. In the tar, laevoglucosan has been determined by an infra-red absorption method, and by gas-liquid chromatography of its trimethylsilyl ether; 5-(hydroxymethyl)furfural and 1,6-anhydro-β-D -glucofuranose have been identified and determined similarly by gas-liquid chromatography. By thin-layer chromatography of the 2,4-dinitrophenylhydrazones, 19 carbonyl compounds have been identified in the products from pure cotton; fewer were found from cotton treated with flame-retardants. The distribution of boron, nitrogen, phosphorus and chlorine from appropriate flame-retardants has been determined among the products of pyrolysis of cotton. It is concluded that borax/boric acid, and APO-THPC, act predominantly in the solid phase; Proban appears to act partly in the vapour phase. Mechanisms of pyrolysis are proposed. In a pure cotton cellulose, 1,2-anhydroglucoses are regarded as important intermediates.     

Thermal degradation of polymers. XXIV. Vacuum pyrolysis of poly(p-N,N-diethylaminostyrene); the residue and the fraction volatile at pyrolysis temperature,involatile at room temperature

Comparative studies were made of the residue and the fraction volatile at pyrolysis temperature, involatile at ambient temperature obtained from polystyrene and poly(p-N,N-diethylaminostyrene) degraded under identical conditions. Poly(p-N,N-diethylaminostyrene) yielded a crosslinked glassy residue after pyrolysis at temperatures greater than 250°C, and crosslinking is accompanied by N-alkyl group scission as shown by mass spectrometry. The components of the fraction volatile at pyrolysis temperature, involatile at ambient temperature were separated and identified by GPC and mass spectrometry. Mechanisms involving N-alkyl and N-aryl bond scission are proposed to account for the observed products. Quantitative studies on the effect of pyrolysis temperature and polymer molecular weight on the residue and the volatile fraction are described and discussed. No molecular weight dependence was observed for this system in the range studied.     

The Chemical and Physical Structure of Peat Bitumens

Peat bitumen obtained by solvent extraction of Irish high moor peat was subjected to chemical, structural and rheological characterisation. The bitumen was fractionated on the basis of solubility in n-heptane, toluene and ethyl acetate into wax, resin and asphaltene; each of these major constituent groups was further separated into sub-fractions by column chromatography using solvents of increasing polarity. All materials were chemically characterised by C, H, N and O content and infra-red spectroscopy. Molecular size distribution of the materials was determined by gel permeation chromatography and vapour pressure osmometry. Heats of fusion, measured using the differential scanning calorimeter, indicated that crystalline species were concentrated in the wax fraction. The rheological properties of the bitumen were investigated between 10 and 50°C, and the fractions were examined at 20°C. Following analysis as yield pseudoplastic fluids, flow behaviour was described in terms of yield stress, flow and consistency indices. The measured flow parameters were examined in the light of the structural implications of the calorimetry and the results of the chemical analysis. Carboxylic acids and esters which are found principally in the wax fraction are considered to be the dominating rheological influence in the bitumen, affecting physical behaviour through their ability to crystallise at low temperature and thus mechanically hinder flow, and through secondary bonding increasing viscosity in the liquid phase.     

Production of hydrocarbons by pyrolysis of methyl esters from rapeseed oil

The pyrolysis of a mixture of methyl esters from rapeseed oil has been studied in a tubular reactor between 550 and 850°C and in dilution with nitrogen. A specific device for the condensation of cracking effluents was used for the fractionated recovery of liquid and gaseous effluents, which were analyzed on-line by an infrared analyzer and by gas chromatography. The cracking products in the liquid effluent were identified by gas chromatography/mass spectrometry coupling. The effects of temperature on the cracking reaction were studied for a constant residence time of 320 ms and a constant dilution rate of 13 moles of nitrogen/mole of feedstock. The principal products observed were linear 1-olefins,n-paraffins, and unsaturated methyl esters. The gas fraction also contained CO, CO₂, and H₂. The middle-chain olefins (C₁₀–C₁₄ cut) and short-chain unsaturated esters, produced with a high added value, had an optimum yield at a cracking temperature of 700°C.     

Chemical Recycling of Polyolefins with the Molten Metal Reactor at 460 °C

This paper describes the pyrolysis of high-density polyethylene (HDPE) in a molten metal reactor, where the HDPE is initially in direct contact with molten metal at 460 °C. Due to the equal temperature across the molten metal, secondary reactions are minimised, and long-chain waxes with boiling points over 600 °C accumulate on the molten metal. Once enough wax has accumulated, further HDPE pyrolysis occurs within the wax in a direct heat transfer reaction.     

Slow pyrolysis of pistachio shell

In this study, pistachio shell is taken as the biomass sample to investigate the effects of pyrolysis temperature on the product yields and composition when slow pyrolysis is applied in a fixed-bed reactor at atmospheric pressure to the temperatures of 300, 400, 500, 550, 700 °C. The maximum liquid yield was attained at about 500–550 °C with a yield of 20.5%. The liquid product obtained under this optimum temperature and solid products obtained at all temperatures were characterized. As well as proximate and elemental analysis for the products were the basic steps for characterization, column chromatography, FT-IR, GC/MS and SEM were used for further characterization. The results showed that liquid and solid products from pistachio shells show similarities with high value conventional fuels.     

Pyrolysis of pitch derived from hydrocracked athabasca bitumen

Results of isothermal and temperature-programmed pyrolysis experiments in an inert atmosphere and at temperatures from 350 to 1000 °C are presented. Thermogravimetric techniques using a recording microbalance were employed for following the weight changes occurring during the pyrolysis. Several techniques including ¹³C n.m.r., gas chromatography, mass spectrometry and standard ASTM methods were used to analyse the decomposition products and the unreactive char. The bulk of the weight loss, as much as 35% by weight of the original sample, occurs at temperatures below 500 °C. The mechanism of pyrolysis can be adequately described as proceeding in two stages. During the first stage, when about 20% of the sample decomposes, the pyrolytic reactions follow overall firstorder kinetics. During this stage the apparent activation energy and the pre-exponential factor both increase with increasing extent of reaction and exhibit a kinetic compensation effect. During the remainder of the pyrolysis, the activation energy decreases with increasing extent of reaction and the kinetics become complex.     

Value-added products from waste: Slow pyrolysis of used polyethylene-lined paper coffee cup waste

The objectives of this study were to examine how to recycle cup waste efficiently and effectively and to determine if cup waste can be converted into liquid, solid, and gas value-added products by slow pyrolysis. The characteristics and potential utilizations of the pyrolysis products were investigated. The study included the effects of temperature, heating rate, and different feedstocks. The yield of pyrolysis oil derived from cup waste increased from 42% at 400°C to 47% at 600°C, while the yield of char decreased from 26% at 400°C to approximately 20% at 600°C. Acetic acid and levoglucosan were identified as the main components of the pyrolysis oil. The char obtained at 500°C was physically activated at 900°C for 3 h with CO₂. The adsorption capacity of the activated char was investigated with model compounds, such as methyl orange, methylene blue, ibuprofen, and acetaminophen. The results showed that the adsorption capacity of the activated char was similar to that of commercial activated carbon produced from peat. The higher heating value of the produced gas stream calculated at 400°C was 19.59 MJ/Nm³. Also, conventional slow pyrolysis (CSP) and microwave-assisted pyrolysis (MAP) technologies were compared to determine the differences in terms of products yields, composition and characteristics of the pyrolysis oil, and their potential applications. The CSP yields higher liquid products than MAP. Also, the pyrolysis oil obtained from the CSP had significantly more levoglucosan and acetic acid compared to that of the MAP.     

Component composition of deresined brown coal wax

The products of the alkaline hydrolysis of wax isolated from brown coal from the Sergeevskoe deposit were studied using chromatography and IR and NMR spectroscopy. It was found that hydrocarbons, alcohols, acids, and a representative fraction of unsaponifiable esters were the constituents of wax. High-molecular-weight fatty alcohols and acids were identified as the constituents of wax with the use of thin-layer chromatography.