Search results for "Pyrolysi"
showing 10 items of 170 documents
Sewage Sludge Derived Materials for CO2 Adsorption
2021
The study tried to contribute to solving two serious environmental issues: CO2 reducing and sewage sludge disposal. Thus, sewage-sludge-derived materials were obtained in order to be evaluated for CO2 adsorption capacity. Therefore, the char resulted after the sewage sludge pyrolysis was subjected to oxidation and chemical activation processes by using different quantities of alkaline hydroxide. One of the obtained materials, activated with a lower quantity of alkaline hydroxide, was also treated with acid chloride. Further, the materials were structural and texturally characterized, and material treated with acid chloride was used for CO2 adsorption tests, due to high surface area and pore…
Influence of Temperature on Characteristics of Particulate Matter and Ecological Risk Assessment of Heavy Metals during Sewage Sludge Pyrolysis
2021
The formation process of Particulate Matter (PM) during sludge pyrolysis at different temperatures (300–700 °C) and the ecological risks of heavy metals were studied. The results showed that the particulate matter is mainly condensed on the quartz film in a carbon-based organic matter when the pyrolysis temperature was between 200–500 °C in a volatilization process. Inorganic particles was found in the particulate matter when the temperature was raised to 500–700 °C in a decomposition stage. Heavy metals were enriched in particulate matter with increase in pyrolysis temperature. When the temperature reached 700 °C, the concentration of Pb and Cd in the particulate matter significantly incre…
Strukturuntersuchung von Polyestern durch direkten Abbau im massenspektrometer, 5. Polyester aus Terephthalsäure und/oder Bernsteinsäure und Hydrochi…
1978
The structure and thermal degradation behaviour of polyesters from terephthalic and/or succinic acid and hydroquinone were investigated by pyrolysis mass spectrometry. Poly(oxysuccinyloxy-1,4-phenylene) (2) undergoes cleavage of the ester bond (Eq. (vii)) as a very selective pyrolysis mechanism at 310°C, whereas the thermally more stable poly(oxyterephthaloyloxy-1,4-phenylene) (1) starts to degrade above 400°C and yields pyrolysis products with phenyl (Eq. (iv)), p-hydroxyphenyl (Eq. (iii)), benzoyl (Eq. (iiv)) and carboxylic end groups. A calibration curve of the intensities of monomer specific fragments, obtained from pyrolysis mass spectra of polyesters from terephthalic acid, succinic a…
Characterization of acrylic resins used for restoration of artworks by pyrolysis-silylation-gas chromatography/mass spectrometry with hexamethyldisil…
2006
A procedure based on the technique of the pyrolysis-GC/MS has been applied, in this work, in order to determine the composition of synthetic acrylic resins employed in artworks. The method is based on the on line derivatization of these resins using hexamethyldisilazane (HMDS). Results obtained have been compared with those others from direct pyrolysis and in situ thermally assisted hydrolysis and methylation with tetramethylammonium hydroxide (TMAH). Sensitivity using HMDS as derivatising reagent is found similar to that from direct pyrolysis and methylation with TMAH. Better resolution of the most representative peaks has been also obtained. Additionally, this method reduces the formation…
Analytical characterization of diterpenoid resins present in pictorial varnishes using pyrolysis–gas chromatography–mass spectrometry with on line tr…
2005
Abstract A procedure based on the technique of the pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) has been applied, in this work, in order to determine the composition of diterpenoid resin employed in art works. The method is based on the on line derivatization of these resins using hexamethyldisilazane (HMDS). Results obtained were compared with those previously reported in literature from Venice turpentine, Strasbourg turpentine, colophony, sandarac and Manila copal using this same method and with those others from in situ thermally assisted hydrolysis and methylation with tetramethylammonium hydroxide (TMAH). Canada balsam, copper resinate and Copaiba balsam have been also ana…
Pyrolysis study of sol-gel derived TiO2powders
2004
An amorphous TiO2 gel was obtained by hydrolysing titanium(IV) isopropoxide with a stoichiometric amount of water using SnCl2 as catalyst. In these operative conditions, a TiO2 gel matrix containing a lower fraction of organic residual was obtained with respect to samples prepared by previously modifying the titanium alkoxide precursor with chelating ligands. Dried gel powders were characterized by N2 adsorption analyses, FT-IR and XRD measurements. Thermogravimetric (TG) and differential thermal analysis (DTA) coupled with mass spectrometric (MS) and gas chromatographic (GC) measurements were performed in order to identify the organic products released from TiO2 gel pyrolysis. The Tg-MS se…
The effect of feedstock origin and temperature on the structure and reactivity of char from pyrolysis at 1300–2800 °C
2018
This study reports the effect of feedstock origin, residence time, and heat treatment temperature on CO2 and O2 reactivities, nanostructure and carbon chemistry of chars prepared at 1300, 1600, 2400, and 2800 °C in a slow pyrolysis reactor. The structure of char was characterized by transmission electron microscopy and Raman spectroscopy. The CO2 and O2 reactivity of char was investigated by thermogravimetric analysis. Results showed that the ash composition and residence time influence the char reactivity less than the heat treatment temperature. The heat treatment temperature and co-pyrolysis of pinewood char with biooil decreased the CO2 reactivity, approaching that of metallurgical coke…
Upgrade of citrus waste as a biofuel via slow pyrolysis
2015
Abstract Slow pyrolysis (200–650 °C) experiments on citrus residues (orange peel waste “OP” and lemon peel waste “LP”) were carried out in lab scale fixed bed batch reactor. Bio-oil and bio-char obtained by thermal degradation are more stable, more homogeneous and higher energy content fuels when compared to the parent feedstock. Thermogravimetric analysis (TGA) showed higher stability of LP waste, which appears related to the higher lignin content . Mass and energy yields of solid and liquid products (i.e., char and oil) were measured to determine the effects of peak temperature on feedstock. A linear correlation between Gross Calorific Value (GCV), peak temperatures and mass loss (ML) all…
A salt-induced mechanism for the swelling of black liquor droplet during devolatilization
2017
Abstract Black liquor (BL) from the pulp and paper industry is a significant bioenergy source. Swelling of BL droplet during the pyrolysis stage of combustion and gasification is a profound phenomenon affecting various boiler processes. However, the mechanism for droplet swelling has remains a puzzle due to an insufficient understanding of the formation of the plastic droplet at the pyrolysis stage of the thermal conversion. Thermogravimetric studies with model aliphatic carboxylates unraveled the melting and decomposition behavior of the complex mixture of BL salts during pyrolysis, indicating that the melting of salts forming a liquid state may be the primary cause for the development of …
Characterization and reactivity of charcoal from high temperature pyrolysis (800-1600°C)
2019
This study presents the effect of wood origin and heat treatment temperature on the CO2 reactivity, nanostructure and carbon chemistry of chars prepared at 800, 1200, and 1600 °C in slow pyrolysis reactors. The structure of charcoal was characterized by transmission electron microscopy, Raman spectroscopy, mercury intrusion porosimetry and N2 adsorption. The CO2 reactivity of char was investigated by thermogravimetric analysis. Results showed that spruce and oak chars have similar reactivity at all heat treatment temperatures. The oak char prepared at 1600 °C contained long and flat graphene layers and interplanar distance that is similar to graphite and thus, was more ordered t…