Showing papers on "Pyrolysis published in 2001"

Thermal Degradation Chemistry of Alkyl Quaternary Ammonium Montmorillonite

Abstract: The thermal stability of organically modified layered silicate (OLS) plays a key role in the synthesis and processing of polymer-layered silicate (PLS) nanocomposites. The nonoxidative thermal degradation of montmorillonite and alkyl quaternary ammonium-modified montmorillonite were examined using conventional and high-resolution TGA combined with Fourier transform infrared spectroscopy and mass spectrometry (TG−FTIR−MS) and pyrolysis/GC−MS. The onset temperature of decomposition of these OLSs was approximately 155 °C via TGA and 180 °C via TGA−MS, where TGA−MS enables the differentiation of water desorbtion from true organic decomposition. Analysis of products (GC−MS) indicates that the initial degradation of the surfactant in the OLS follows a Hoffmann elimination reaction and that the architecture (trimethyl or dimethyl), chain length, surfactant mixture, exchanged ratio, or preconditioning (washing) does not alter the initial onset temperatures. Catalytic sites on the aluminosilicate layer reduce ther...

In situ thermal processing of a hydrocarbon containing formation to produce a hydrocarbon condensate

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. Hydrocarbons, H 2 , and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat input into the formation may be controlled to raise a temperature of the formation at a selected rate.

Progress in Thermochemical Biomass Conversion

Abstract: Combustion: Co-combustion of coal and biomass wastes in fluidised bed Development of catalytic wood fired boiler The mathematical modelling of biomass pyrolysis in a fixed bed and experimental verification Operating parameters for the circulating fluidised bed (CFB) processing of biomass Combustion properties of a fuel bed - Experimental and modelling study Summary of recent parametric studies of small-scale domestic biomass combustion Combustion processes in a biomass fuel bed - Experimental results of the influence of airflow and of particle size and density Influence of the ash composition in slagging and defluidisation in a biomass fired commercial CFB boiler A new type of a boiler plant for dry and wet biofuel Gasification: Modern technologies of biomass conversion Redox process for the production of clean hydrogen from biomass Dynamic Modelling of Char Gasification in a Fixed-Bed A two stage pyrolysis/gasification process for herbaceous waste biomass from agriculture Fundamental fluid-dynamic investigations in a scaled cold model for biomass-steam gasification Biomass Power Generation: Sugar Cane Bagasse and Trash Biomass and waste to energy conversion in the Netherlands by means of (in) direct co-combustion: Status, projects and future applications in the Dutch utility sector Gasification study of biomass mixed with plastic wastes The development of methanol synthesis with biomass gasification Final report: Varnamo demonstration programme Design of a moving bed granular filter for biomass gasification Pyrolysis: Bagasse pyrolysis in a wire mesh reactor BCO/Diesel oil emulsification: Main achievements of the emulsification process and preliminary results of tests on diesel engine Overview of fast pyrolysis Production of hydrogen from biomass-derived liquids Levoglucosenone - A product of catalytic fast pyrolysis of cellulose Pyrolysis and gasification of black liquors from alkaline pulping of straw in a fixed bed reactor Thermal efficiency of the HTU process for biomass liquefaction Low-temperature pyrolysis as a possible technique for the disposal of CCA treated wood waste Mathematical modelling of the flash-pyrolysis process for wood particles Flash pyrolysis of biomass in a conical spouted bed. Kinetic study in the 400-500C range Scale up effect on plastics waste pyrolysis Research on the rotating cone reactor for sawdust flash pyrolysis Thermal desorption technology: Low temperature carbonisation of the biomass for manufacturing of activated carbon Scaling-up and operation of a flash-pyrolysis system for bio-oil production and applications on basis of the rotating cone technology Systems: Utilisation of bagasse residues in power production Barriers for the introduction of biomass in the Netherlands Assessment of the techno-economic viability of a bioelectricity demonstration plant in Spain Innovative components for decentralised combined heat and power generation from biomass gasification A role of bioenergy utilization technologies considering bioenergy supply potential and energy systems using a global energy and land use model

Electroanalytical performance of carbon films with near-atomic flatness.

Abstract: Physicochemical and electrochemical characterization of carbon films obtained by pyrolyzing a commercially available photoresist has been performed. Photoresist spin-coated on to a silicon wafer was pyrolyzed at 1000 °C in a reducing atmosphere (95% nitrogen and 5% hydrogen) to produce conducting carbon films. The pyrolyzed photoresist films (PPF) show unusual surface properties compared to other carbon electrodes. The surfaces are nearly atomically smooth with a root-mean-square roughness of <0.5 nm. PPF have a very low background current and oxygen/carbon atomic ratio compared to conventional glassy carbon and show relatively weak adsorption of methylene blue and anthraquinone-2,6-disulfonate. The low oxygen/carbon ratio and the relative stability of PPF indicate that surfaces may be partially hydrogen terminated. The pyrolyzed films were compared to glassy carbon (GC) heat treated under the same conditions as pyrolysis to evaluate the electroanalytical utility of PPF. Heterogeneous electron-transfer ki...

Microwave-Induced Pyrolysis of Plastic Wastes

Abstract: The performance of a novel microwave-induced pyrolysis process was evaluated by studying the degradation of high-density polyethylene and aluminum/polymer laminates in a semibatch bench-scale apparatus. The results showed that the new process has the same general features as other, more traditional, pyrolytic processes but with the advantage that it is able to deal with problematic wastes such as laminates. Degradation experiments were performed between 500 and 700 °C and the relationship between temperature, residence time of the pyrolytic products in the reactor, and the chemical composition of the hydrocarbon fraction produced was investigated. Toothpaste tubing was used as an example of a laminated material to be treated with the novel process. Clean aluminum was recovered together with hydrocarbons and the trial proved that the process has excellent potential for the treatment of plastic wastes on a commercial scale.

Thermal cross-linking and pyrolytic conversion of poly(ureamethylvinyl)silazanes to silicon-based ceramics

Abstract: The aim of this work was to study the pyrolytic conversion of a novel commercial polysilazane, poly(ureamethylvinyl)silazane (PUMVS; Ceraset™, Allied Signal Composites Inc., USA), into silicon-based ceramics. The precursor was thermally cross-linked and pyrolyzed between 200 and 1700 °C under argon or nitrogen atmosphere and the products were investigated by spectroscopic techniques (FTIR and Raman spectroscopy, solid-state NMR), elemental analysis and simultaneous thermal analysis coupled with mass spectrometry. Upon heating under argon, the starting liquid precursor transformed into an infusible solid polymer at T > 250 °C with a conversion yield of >95 wt%. The cross-linking solidification occurred predominantly through hydrosilylation or addition reaction involving vinyl groups. Subsequent pyrolysis of the cross-linked products around 1000 °C in argon yielded amorphous silicon carbonitride ceramics with a composition of SiN0.82C0.86. The overall ceramic yield (with respect to the starting PUMVS) was around 70 wt%, which was found to be independent of the initial cross-linking step. Solid-state NMR (29Si and 13C) revealed that the amorphous silicon carbonitrides contain predominately CSiN3 units. There is evidence for the formation of free amorphous carbon between 700 and 800 °C. Graphitic phases were detected by X-ray diffraction in the samples heated to T > 1000 °C at high heating rates. Upon annealing at T > 1500 °C, the excess carbon reacted completely with the silicon (carbo)nitride to form SiC and nitrogen. The final ceramics contained a large amount of crystalline SiC (∼90 wt%), and were free of excess carbon or silicon. Therefore, PUMVS is an ideal precursor for the formation of high-quality SiC-based ceramics. Copyright © 2001 John Wiley & Sons, Ltd.

Decomposition of H2O2 on activated carbon obtained from olive stones

Abstract: Activated carbons were prepared from olive oil solid wastes by treatment in different schemes: impregnation with H3PO4 followed by pyrolysis at 300–700 °C, by steam pyrolysis at 600–700 °C, or by conventional steam activation at 850 °C. Porosity characteristics were determined by analysis of nitrogen adsorption isotherms, and carbons of widely different properties and surface pH values were obtained. Decomposition of H2O2 in dilute unbuffered solution was followed by measuring evolved oxygen volumetrically. First-order kinetics was followed, and the catalytic rate coefficients were evaluated. The carbons tested showed appreciable activity where evolved oxygen attained ≈10% of the stoichiometric amount in 1 h. The degree of decomposition showed inverse dependence on surface area, pore volume and mean pore dimensions. The chemical nature of the surface, rather than the porosity characteristics, was the principal factor in enhancing the disproportionation of H2O2 on the activated carbon surface. © 2001 Society of Chemical Industry