Search results for "combustion"
showing 10 items of 232 documents
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 …
On the self-heating behavior of upgraded biochar pellets blended with pyrolysis oil: Effects of process parameters
2020
Abstract Biochar obtained from biomass pyrolysis is a promising carbon neutral material which can be used in substitution of fossil coal and coke in metallurgical applications. Biochar’s mechanical properties improve significantly without compromising reactivity, when upgraded by densification with pyrolysis oil and reheated. However, upgraded biochar pellets use in the industry is limited due to the risks associated with self-heating. This issue must be seriously considered for further industrial production of upgraded biochar pellets. Self-heating oven tests are generally time-consuming and limit the possibility of testing various potential solutions. The aim of this work was both to inve…
Thermal and thermo-oxidative stability of reprocessed poly(ethylene terephthalate)
2013
An exhaustive assessment of the behaviour of virgin and mechanically reprocessed poly(ethylene terephthalate) (PET) facing thermal and thermo-oxidative decomposition processes is presented in this work, as an approach for the energetic valorisation of post-consumer PET goods. Multi-rate linear-non-isothermal thermogravimetric (TGA) experiments under inert (Ar) and reactive (O2) conditions were performed to virgin PET and its recyclates in order to simulate the thermal behaviour of the materials facing pyrolysis and combustion processes. The release of gases was monitored by evolved gas analysis of the fumes of the TGA experiment, by in-line Fourier-transform infrared (IR) analysis, with the…
Thermal Stability and Flame Retardancy of Polypropylene Composites Containing Siloxane-Silsesquioxane Resins
2018
A novel group of silsesquioxane derivatives, which are siloxane-silsesquioxane resins (S4SQ), was for the first time examined as possible flame retardants in polypropylene (PP) materials. Thermal stability of the PP/S4SQ composites compared to the S4SQ resins and neat PP was estimated using thermogravimetric (TG) analysis under nitrogen and in air atmosphere. The effects of the non-functionalized and n-alkyl-functionalized siloxane-silsesquioxane resins on thermostability and flame retardancy of PP materials were also evaluated by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and by cone calorimeter tests. The results revealed that the functionalized S4SQ resins may for…
Ceria-based electrolytes prepared by solution combustion synthesis: The role of fuel on the materials properties
2016
Ce0.8Sm0.2O2 â xpowders were synthesized by solution combustion synthesis using citric acid, cellulose and sucrose as single, or intimately mixed, fuels. The powders were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2sorption at â196 °C, H2-temperature programmed reduction and thermogravimetric analyses. Textural properties of the powders were shaped by the peculiar employed fuel. The study of reducibility revealed that oxygen vacancies formation is mainly influenced by both parameters, specific surface area and total pore volume. The different tendency toward reduction played a key role in sintering under reducing atmosphe…
Thermogravimetric analysis as express tool for quality assessment of refuse derived fuels used for pyro-gasification
2019
The development of pyro-gasification technologies makes necessary the development of new express analytical methods that are able to deal with the variability of feedstock and problems arising from it. Thermogravimetric proximate analysis of refuse derived fuels is a very fast, cheap and simple method for the determination of proximate and fractional composition. Development of this analytical approach may result in a very cost-effective method to describe wholesome composition and characteristics of feedstock used for pyrolysis and gasification processes in real time. The aim of this study was the development of such analytical method. Refuse derived fuel samples produced in Latvia and Est…
Characterization of the light-absorbing properties, chromophore composition and sources of brown carbon aerosol in Xi'an, northwestern China
2020
The impact of brown carbon aerosol (BrC) on the Earth's radiative forcing balance has been widely recognized but remains uncertain, mainly because the relationships among BrC sources, chromophores and optical properties of aerosol are poorly understood. In this work, the light absorption properties and chromophore composition of BrC were investigated for samples collected in Xi'an, northwestern China, from 2015 to 2016. Both absorption Ångström exponent (AAE) and mass absorption efficiency (MAE) show distinct seasonal differences, which could be attributed to the differences in sources and chromophore composition of BrC. Three groups of light-absorbing organics were found to be important Br…
Measurement report: PM<sub>2.5</sub>-bound nitrated aromatic compounds in Xi'an, Northwest China – seasonal variations an…
2021
Abstract. Nitrated aromatic compounds (NACs) are a group of key chromophores for brown carbon (light-absorbing organic carbon, i.e., BrC) aerosol, which affects radiative forcing. The chemical composition and sources of NACs and their contributions to BrC absorption, however, are still not well understood. In this study, PM 2.5 -bound NACs in Xi'an, Northwest China, were investigated for 112 daily PM 2.5 filter samples from 2015 to 2016. Both the total concentrations and contributions from individual species of NACs show distinct seasonal variations. The seasonally averaged concentrations of NACs are 2.1 (spring), 1.1 (summer), 12.9 (fall), and 56 ng m −3 (winter). Thereinto, 4-nitrophenol …
The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content
2011
Abstract Immediately following a wildfire, a layer of ash and charred material typically covers the ground. This layer will gradually be reduced, being redistributed by rainfall, wind or animals, by partial dissolution and by incorporation into the soil. Ash can increase or decrease the post-fire runoff and erosion response, depending upon the soil and ash properties and the ash thickness. One aspect of ash that has remained unknown and which may affect the variability in the hydrological response of the burned soil is its wettability. This study examines the wettability of ash using the Water Drop Penetration Time (WDPT) test, its relationship with total organic carbon (TOC) content and co…